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Biomedical subjects

B F King

Publications and source records attributed to B F King.

At least 127 records · Page 7Linked to original sources
PubMed1991

Advances in gynecologic imaging and intervention.

Advances in diagnostic imaging of the female genital tract facilitate characterization of many pelvic masses. Preoperative assessment of gynecologic malignant tumors provides information that may alter the surgical approach or timing of radiation therapy. Image-guided biopsy accurately confirms recurrent malignant lesions. Transcervical techniques have improved diagnostic assessment of infertile couples; thus, effective and inexpensive treatment options can be offered. Postoperative complications of gynecologic procedures can be detected with imaging, and many can be treated with image-guided techniques.

Female↗
PubMed1991

Magnetic resonance imaging for calf deep venous thrombophlebitis.

STUDY OBJECTIVE: To compare magnetic resonance imaging (MRI) of the calf with venography for patients with suspected calf deep venous thrombophlebitis (DVT). DESIGN: Ten consecutive adult patients with suspected calf DVT received venography and, within 48 hours, MRI scans. The tests were reviewed blindly by two radiologists, and results of the tests were compared. SETTING: The emergency department of a large teaching hospital with an annual census of 60,000 patients. MAIN RESULTS: All patients with negative venograms had no suggestion of DVT on MRI scan. Two of these patients had other significant demonstrable abnormalities. Four of the five patients with positive venograms had positive calf MRI scans. One patient with a venogram that was difficult to interpret had no DVT on MRI. A thigh DVT was seen on his venogram and was suggested by MRI findings. CONCLUSION: MRI may replace ascending venography as the standard for diagnosis of calf DVT.

Emergency Medicine↗
PubMed1991

Cell-mediated infection of human placental trophoblast with HIV in vitro.

In order to investigate how human immunodeficiency virus (HIV) gains entry to the placenta, we have performed in vitro experiments in which highly purified trophoblast cells isolated from term human placentas were examined for their susceptibility to HIV infection. Trophoblast cells were exposed to cell-free HIV-1 for up to 24 h, after which the cultures were monitored by p24 antigen capture assay, reverse transcriptase assay, and electron microscopy for evidence of virus uptake and replication. None was found. In the second series of experiments, trophoblast cells were cocultured with HIV-infected MOLT-4 cells for 24 h, stained using an anti-HIV antibody, and examined by immunofluorescence microscopy. The MOLT cells were strongly positive, as expected, but many trophoblast colonies also showed a punctate staining pattern. Examination of similar cultures using the electron microscope revealed MOLT cells adherent to trophoblast but no evidence of cell-cell fusion. Virions were observed in coated pits at the trophoblast cell surface and in endosomes or multivesicular bodies in the cytoplasm. These observations are consistent with an endocytosis-mediated mechanism of virus entry. Virions were also observed budding from the trophoblast plasma membrane, indicating that these cells can support HIV replication. To our knowledge, these results show for the first time that HIV can infect placental trophoblast cells in vitro. The results suggest that the placenta could become infected with HIV by the interaction of virus-infected maternal lymphocytes with syncytiotrophoblast bordering the maternal blood in the intervillous space.

Female↗
PubMed1991

Congenital cystic disease of the seminal vesicle.

Thirteen cases of congenital seminal vesicle cysts with pathologic correlation were diagnosed between 1970 and 1988. Twelve of the 13 patients had ipsilateral renal anomalies. Intravenous urography, performed in 11 of the 13 patients, demonstrated associated renal anomalies. Computed tomography, performed in nine of the 13 patients, demonstrated associated renal anomalies and displayed the cystic seminal vesicles. Transabdominal or endorectal ultrasonography, performed in eight patients, allowed characterization of the seminal vesicle masses as cystic. Magnetic resonance imaging, performed in three of the 13 patients, accurately demonstrated dilated ejaculatory ducts into which ectopic ureters inserted. The fluid in the seminal vesicle cysts had an increased signal intensity on T1- and T2-weighted sequences. Seminal vesiculographic study demonstrated anomalous communications with the seminal tract. Cystic disease of the seminal vesicles can be either congenital or acquired; congenital cysts are associated with anomalies of the ipsilateral mesonephric duct.

Adult↗
PubMed1991

Vasculogenic impotence. Duplex and color Doppler imaging.

Varicoceles, although only occasionally symptomatic, are reported to occur in 20% to 50% of infertile or subfertile men. Ligation or occlusion of the spermatic vein in these patients has improved semen quality in many instances. Recently, it has been recognized that varicoceles can be bilateral or subclinical and thus detected only by imaging. Sonographic diagnosis of varicoceles and percutaneous occlusive therapy are reviewed in this article.

Color↗
PubMed1990

Isolation and morphologic differentiation in vitro of villous cytotrophoblast cells from rhesus monkey placenta.

Trophoblast is the major functional cell type of the placenta. The purpose of this study was to devise a means to isolate trophoblast cells from the monkey placenta and to examine their capacity to differentiate in vitro. Methods originally devised for the isolation of human cytotrophoblast cells produced poor yields and a low degree of purity when applied to the near-term rhesus monkey placenta. However, a procedure has been developed which allows the isolation of a cell population consisting of more than 95% cytotrophoblast based on intermediate filament immunocytochemistry. The cells sedimented between densities of 1.040 and 1.053 g/ml on continuous Percoll density gradient centrifugation. When maintained in culture the cells adhered and formed aggregates of mononuclear cells by 24 h. By 5 d in culture, immunofluorescent staining using antidesmoplakin and antinuclear antibodies revealed that most colonies consisted of large multinucleated masses similar to syncytiotrophoblast. These results demonstrate trophoblast cells from monkey placental villi can be isolated with a high degree of purity and undergo morphologic differentiation in vitro. This preparation should enable investigators to study many functional characteristics of these cells throughout gestation.

Animals↗
PubMed1990

Differentiation of human trophoblast cells in vitro as revealed by immunocytochemical staining of desmoplakin and nuclei.

The differentiation of isolated human cytotrophoblast cells has been studied by staining cells with anti-desmoplakin antibodies, to reveal cell boundaries, and with anti-nuclear antibodies, to reveal nuclei. During the first 24 h after plating in Ham's/Waymouth medium, mononucleated cytotrophoblast cells began to spread and aggregate, forming colonies. This was accompanied by progressive changes in the pattern of desmoplakin staining. In single cells, desmoplakin was dispersed throughout the cytoplasm. As cells aggregated, desmoplakin was redistributed and formed linear, punctate arrays at regions of cell-cell contact, consistent with desmosome formation. A pavement-like staining pattern was maintained even at 5 days. Double staining for desmoplakin and nuclei revealed that most cells within colonies were mononucleated. When plated in a growth medium originally formulated for keratinocytes, cytotrophoblast cells aggregated and formed desmosomes normally. However, after 48 h, cell diameters were increased and nuclei changed from being evenly distributed to forming clusters within large cells, consistent with syncytiotrophoblast formation. While cells grown in Ham's/Waymouth medium for 2 days could be induced to differentiate by switching to keratinocyte growth medium, cells cultured for 5 days before switching were resistant to the differentiation-inducing effects of the keratinocyte medium. Desmosome-type junctions within colonies of trophoblast cells were unstable and, even after 5 days in culture, could be disrupted by lowering the extracellular Ca2+ concentration. While syncytiotrophoblast formation in keratinocyte growth medium (which contains epidermal growth factor, insulin and hydrocortisone) was accompanied by a 15- to 20-fold increase in chorionic gonadotropin secretion, syncytiotrophoblast formation occurred to a similar extent in keratinocyte basal medium (which does not contain these factors) but with only a twofold increase in chorionic gonadotropin release. These results support the notion that biochemical and morphological differentiation of trophoblast are independent events.

Antibodies, Monoclonal↗
PubMed1990

Value of MR imaging in differentiating benign from malignant soft-tissue masses: study of 95 lesions.

MR imaging has largely replaced CT as the technique of choice for preoperative staging of patients with soft-tissue masses. Whether MR imaging can be used to differentiate benign from malignant masses is controversial. Our experience suggests that MR imaging often can characterize soft-tissue masses accurately. To evaluate this question further, we studied 95 consecutive lesions (50 benign and 45 malignant). Consecutive cases were selected to simulate our clinical practice. Surgical proof was available for all masses except hematomas, for which clinical follow-up confirmed the diagnosis. MR images were interpreted twice by three radiologists. The first review was accomplished without any clinical history and the second review with clinical history. Reviewers were asked to classify the lesion as benign or malignant on the basis of their clinical knowledge and analysis of MR image features (size, lesion margin, signal homogeneity, and neurovascular or bone involvement). Although interpretation varied somewhat because of the experience of the reviewers, the specificity and accuracy of diagnosis averaged 90% for both benign and malignant lesions. Negative predictive value for malignancy averaged 94% among the three reviewers. MR imaging is the technique of choice for identification and characterization of soft-tissue masses. The nature of the lesion (benign vs malignant) can be determined in the majority of cases.

Diagnosis, Differential↗
PubMed1989

Isolation of pure villous cytotrophoblast from term human placenta using immunomagnetic microspheres.

A procedure has been developed which yields a pure population of villous cytotrophoblast from term human placenta. As a first step, a cell preparation highly enriched for cytotrophoblast (identified by positive cytokeratin staining) was obtained using a modification of the method of Kliman et al. (1986). The remaining contaminating cells (identified by positive vimentin staining) were then removed by treatment with mouse monoclonal antibodies against class I and class II major histocompatibility antigens followed by magnetic microspheres coated with goat anti-mouse IgG. The rationale for this step was based on the fact that villous trophoblast fails to express HLA antigens whereas cells from the villous mesenchyme do express these surface antigens. Rosetted cells were immobilized using a magnet allowing the non-rosetted cells to be easily withdrawn by pipette. When the non-rosetted cells were placed in primary culture, no HLA-positive or vimentin-positive cells could be detected using immunofluorescence microscopy, indicating complete removal of these components by the immunomagnetic separation procedure. The cells were positive for cytokeratin and, after 24 h, showed positive staining for pregnancy-specific beta 1-glycoprotein (SP1) and human chorionic gonadotropin. Recovery of cytotrophoblast was greater than 92% with only a slight loss of viability.

Animals↗
PubMed1989

Immunohistochemical localisation of a gastrin-releasing peptide-like material in area postrema, nucleus of the solitary tract and vagal motor nucleus in the brainstem of rat.

The presence of an endogenous gastrin-releasing peptide (GRP)-like peptide in the hindbrain of rat was demonstrated immunohistochemically using antisera directed against the N-terminus and C-terminus of GRP. N-terminal and C-terminal-like immunoreactive material were distributed throughout the nucleus of the solitary tract (NTS), dorsal motor nucleus of the vagus (DMV) and tractus solitarius (TS), as well as in areas postrema (AP) and substantia gelatinosa separating AP from NTS. Positive immunostaining was localised to a dense network of nerve fibres which project longitudinally along the neuraxis. Immunolabelled cell bodies were observed rostral to the obex, principally in the mediolateral subnucleus of NTS. These immunopositive neurones project their axons caudally and longitudinally towards the commissural subnucleus of the NTS. Immunolabelled cell bodies also were found in AP; they projected their axons caudally and ventrally towards NTS. Positive immunostaining was blocked by pre-adsorbing antisera with either GRP (1 nmol/ml) or bombesin (3 nmol/ml), but was unaffected by substance P (30 nmol/ml) and spared by capsaicin pretreatments which deplete sensory nerves of their peptide content. The results indicate that NTS neurons containing a GRP-like peptide connect the rostral and caudal regions of the dorsal vagal complex by way of longitudinal nerve tracts descending NTS and TS. Some neurons in AP also contain a GRP-like peptide and appear to connect with the dorsal vagal complex.

Animals↗
PubMed1989

Low-osmolality contrast media: a current perspective.

Intravascular radiographic contrast media play a major role in diagnostic imaging. Recently, low-osmolality contrast media (LOCM) have become available in the United States. Because of their lower osmolality, these new agents cause fewer undesirable physiologic effects and fewer adverse reactions than do conventional agents after intravascular administration. Unfortunately, the cost of LOCM is substantially higher than the cost of conventional contrast media. Appropriate use of these newer, more expensive contrast agents must be based on a thorough knowledge and understanding of their chemistry, physiologic features, and relative safety. Some questions remain about these new agents. Further studies are needed to determine the nephrotoxicity of LOCM relative to that of conventional agents. In addition, LOCM have less anticoagulant capacity than do the conventional media; therefore, clotting may occur when the LOCM and blood mix in syringes and small catheters. This potential decrease in anticoagulation and its clinical implications should be further investigated. Finally, the mortality rate associated with use of LOCM needs to be determined in future studies in large numbers of patients.

Contrast Media↗
PubMed1989

Intracellular recordings from pancreatic ganglia of the cat.

1. The anatomy, morphology, and electrophysiology of parasympathetic ganglia of cat pancreas were studied in vitro. 2. Pancreatic ganglia existed as an interconnected plexus of small ganglia (ten to fifty cells) lying in the interlobular connective tissue. Occasionally smaller ganglia (four to ten cells) were observed lying on or within nerve trunks. 3. Electron micrographs revealed the presence of neurones and satellite cells as well as unmyelinated axons and nerve terminals. Nerve terminals contained small clear vesicles and/or large, dense-cored vesicles. 4. Intracellular recording of electrical activity revealed the presence of two types of ganglion cells. Type I ganglion cells exhibited resting membrane potentials that ranged from -40 to -63 mV and input resistances that ranged from 8 to 168 M omega. They responded to intracellular depolarizing current with action potentials, and received synaptic inputs which when activated caused fast and slow depolarizing responses. Type I cells were considered to be ganglionic neurones. Type II ganglion cells had higher resting membrane potentials that ranged from -61 to -83 mV, lower input resistances that ranged from 5 to 83 M omega and were electrically unexcitable. Repetitive stimulation of preganglionic nerves evoked a slow depolarization that was frequency dependent. Type II cells were considered to be satellite cells. 5. Stimulation of nerve trunks both central and peripheral to the ganglia evoked multiple, subthreshold, fast EPSPs in all type I cells tested. Fast EPSPs were blocked by the nicotinic antagonist hexamethonium. 6. Antidromic potentials were also observed following stimulation of either central or peripheral nerve trunks but never both. 7. In type I cells repetitive stimulation of both central and peripheral nerve trunks resulted in a slow, synaptically mediated depolarization which persisted during superfusion with nicotinic and muscarinic receptor antagonists. 8. Periods of low-frequency, spontaneous fast EPSPs and action potentials were observed in all type I cells tested. 9. It was concluded that parasympathetic neurones in cat pancreatic ganglia receive convergent fast and slow synaptic inputs from central and possibly peripheral sources and may function in vivo as sites of integration. The occurrence of spontaneous synaptic potentials in pancreatic ganglia suggests the possibility of intrinsic neural control of pancreatic function.

Animals↗
PubMed1989

Seminal vesicle imaging.

The purpose of this paper is to enhance the understanding of CT, MRI and US images of the seminal vesicles. Accurate interpretation of images requires knowledge of normal anatomy, embryology and pathology. Anatomy and a spectrum of abnormalities are reviewed and discussed. Cases are from an analysis of clinical and surgical files to show the diagnostic features of various cystic diseases of the seminal vesicles. Tissue characteristics of the seminal vesicles on CT, MRI and US images are emphasized.

Adult↗
PubMed1989

Peripheral reflex pathways involving abdominal viscera: transmission of impulses through prevertebral ganglia.

In neurophysiological terms, divergence describes the transmission of impulse traffic from a single afferent line, through an integrating nervous system, and out into multiple efferent lines. This feature has been ascribed to the vertebrate central nervous system and invertebrate ganglionic systems but has not yet been associated with the autonomic nervous system in mammals. Therefore, this study investigated the degree of divergence of afferent impulse traffic through a mammalian autonomic ganglion, the inferior mesenteric ganglion (IMG) in guinea pig. Multiunit discharges were recorded extracellularly from the peripheral nerves, which emerge from the IMG, to determine the lines of efferent outflow (i.e., divergence) of impulse traffic generated by stimulating central efferent and peripheral afferent nerves. Pathways interrupted by a cholinergic ganglion synapse were identified by using hexamethonium. Pathways running directly through the IMG were identified by studying the effects of dividing nerves surgically. A complex arrangement of ascending and descending pathways was revealed, showing a neural network that interconnects the upper gastrointestinal tract, distal colon, and pelvic viscera via prevertebral ganglia.

Animals↗
PubMed1989

Duplex and color Doppler sonographic evaluation of vasculogenic impotence.

One hundred eighty patients with suspected vasculogenic impotence were evaluated with conventional penile duplex sonography with spectral analysis and color Doppler imaging. Measurements of mean peak systolic and end-diastolic velocities were obtained from the cavernosal arteries before and after intracavernosal injections of papaverine. Sixty-one patients were examined with dynamic cavernosography and cavernosometry, and 12 patients were studied with selective internal pudendal and penile arteriography. All five patients with abnormal arteriography had mean peak systolic velocities in the cavernosal arteries of less than or equal to 25 cm/sec (sensitivity, 100%; 95% confidence interval, 48-100%) after the injection of papaverine. Six of the seven patients with normal arteriography had mean peak systolic velocities of greater than 25 cm/sec (specificity, 85.7%; 95% confidence interval, 42-100%) after injection of papaverine. By using data from a receiver-operating-characteristic curve, we determined that end-diastolic velocities in the cavernosal arteries of greater than or equal to 5 cm/sec after the injection of papaverine correctly identified patients with excessive venous leakage on cavernosometry; the sensitivity was 90% (95% confidence interval, 77-97%) and the specificity was 56% (95% confidence interval, 30-80%). The addition of color Doppler sonography made the detection of vessels easier and the correction of the Doppler angle more accurate, resulting in more rapid and accurate acquisition of data. Penile duplex sonography with spectral analysis and color Doppler imaging are sensitive and noninvasive means of examining patients with potential vasculogenic impotence.

Adolescent↗