Ovine osteopontin: II. Osteopontin and alpha(v)beta(3) integrin expression in the uterus and conceptus during the periimplantation period

Osteopontin (OPN) is an acidic 70-kDa glycoprotein that is cleaved by proteases to yield 45-kDa and 24-kDa fragments. The 70-kDa and 45-kDa proteins contain a Gly-Arg-Gly-Asp-Ser (GRGDS) sequence that binds to cell surface integrins (primarily alpha(v)beta(3) heterodimer) to promote cell-cell attachment and cell spreading. A 70-kDa acidic protein was previously detected by two-dimensional (2D) PAGE in Day 17 pregnant endometrial cytosolic extracts using Stainsall and identified as immunoreactive OPN using Western blotting. Three forms of immunoreactive OPN proteins (70, 45, and 24 kDa) were detected by 1D PAGE and Western blot analysis of endometrial extracts. OPN protein in endometrial extracts did not differ between cyclic and pregnant ewes. However, the amount of 45-kDa OPN increased in uterine flushings from pregnant ewes between Days 11 and 17. Immunoreactive OPN was localized to luminal and glandular epithelia of both cyclic and pregnant ewes, and to trophectoderm of Day 19 conceptuses. The alpha(v) and beta(3) integrins were detected on Day 19 endometrium and conceptuses by immunofluorescence. It was reported that OPN mRNA increases in the uterine glands of pregnant ewes and secretion of OPN protein into the uterine lumen increases during early pregnancy. The present results demonstrate accumulation of OPN protein on endometrial LE and conceptus trophectoderm. Therefore, it is hypothesized that progesterone and/or interferon-tau induce expression, secretion and/or proteolytic cleavage of OPN by uterine epithelium. Secreted OPN is then available as ligand for alpha(v)beta(3) integrin heterodimer on trophectoderm and uterus to 1) stimulate changes in morphology of conceptus trophectoderm and 2) induce adhesion between luminal epithelium and trophectoderm essential for implantation and placentation.

Spatially resolved measurements of hyperpolarized gas properties in the lung in vivo. Part I: diffusion coefficient

In imaging of hyperpolarized noble gases, a knowledge of the diffusion coefficient (D) is important both as a contrast mechanism and in the design of pulse sequences. We have made diffusion coefficient maps of both hyperpolarized (3)He and (129)Xe in guinea pig lungs. Along the length of the trachea, (3)He D values were on average 2.4 cm(2)/sec, closely reproducing calculated values for free gas (2.05 cm(2)/sec). The (3)He D values measured perpendicular to the length of the trachea were approximately a factor of two less, indicating restriction to diffusion. Further evidence of restricted diffusion was seen in the distal pulmonary airspaces as the average (3)He D was 0.16 cm(2)/sec. An additional cause for the smaller (3)He D in the lung was due to the presence of air, which is composed of heavier and larger gases. The (129)Xe results show similar trends, with the trachea D averaging 0.068 cm(2)/sec and the lung D averaging 0.021 cm(2)/sec. Magn Reson Med 42:721-728, 1999.

Differential effects of intrauterine and subcutaneous administration of recombinant ovine interferon tau on the endometrium of cyclic ewes

Interferon tau (IFNtau) is the antiluteolytic signal produced by the conceptus of ruminants. Intrauterine administration of recombinant ovine IFNtau suppresses expression of endometrial estrogen receptor (ER) and oxytocin receptor (OTR) in the luminal and superficial glandular epithelia to abrogate the production of luteolytic prostaglandin F(2alpha) (PGF(2alpha)) pulses. Subcutaneous (s.c.) injections of recombinant ovine (o) IFNtau appear to extend the interestrous interval by altering uterine PGF(2alpha) response to oxytocin. The present study tested the hypothesis that antiluteolytic effects of roIFNtau injected into the uterine lumen (paracrine) or s.c. (endocrine) are equivalent in suppressing expression of endometrial ER and OTR and inducing uterine expression of type I IFN-regulated Mx and ubiquitin cross-reactive proteins (UCRP). Sixteen cyclic ewes were fitted with uterine catheters on Day 5 (Day 0 = estrus), were assigned randomly to receive treatment with control proteins or roIFNtau (2 x 10(7) antiviral units/day) by either intrauterine or s.c. injections from Days 11 to 15, and were ovariohysterectomized on Day 16. Results indicated that expression of ER and OTR mRNAs in endometrial epithelium was suppressed by intrauterine but not by s.c. injections of roIFNtau. Intrauterine injections of roIFNtau increased expression of Mx and UCRP mRNA in the endometrium. Subcutaneous injections of roIFNtau increased endometrial Mx mRNA levels but not UCRP mRNA. Unexpectedly, intrauterine and s.c. injections of roIFNtau were equally effective in inducing expression of Mx and UCRP mRNA in the corpus luteum. Although s.c. injections of roIFNtau induced Mx mRNA in the endometrial epithelium, s.c. injections of roIFNtau did not abrogate activation of the uterine luteolytic mechanism by suppressing epithelial ER and OTR expression. Therefore, results of this study failed to support the assumption that endocrine roIFNtau mimics antiluteolytic effects of paracrine IFNtau to improve pregnancy rates in sheep.

Expression of the interferon tau inducible ubiquitin cross-reactive protein in the ovine uterus

Ubiquitin cross-reactive protein (UCRP) is a 17-kDa protein that shows cross-reactivity with ubiquitin antisera and retains the carboxyl-terminal Leu-Arg-Gly-Gly amino acid sequence of ubiquitin that ligates to, and directs degradation of, cytosolic proteins. It has been reported that bovine endometrial UCRP is synthesized and secreted in response to conceptus-derived interferon-tau (IFNtau). In the present studies, UCRP mRNA and protein were detected in ovine endometrium. Ovine UCRP mRNA was detectable on Day 13, peaked at Day 15, and remained high through Day 19 of pregnancy. The UCRP mRNA was localized to the luminal epithelium (LE), stromal cells (ST) immediately beneath the LE, and shallow glandular epithelium (GE) on Day 13, but it extended to the deep GE, deep ST, and myometrium of uterine tissues by Day 15 of pregnancy. Western blotting revealed induction of UCRP in the endometrial extracts from pregnant, but not cyclic, ewes. Ovine UCRP was also detected in uterine flushings from Days 15 and 17 of pregnancy and immunoprecipitated from Day 17 pregnant endometrial explant-conditioned medium. Treatment of immortalized ovine LE cells with recombinant ovine (ro) IFNtau induced cytosolic expression of UCRP, and intrauterine injection of roIFNtau into ovariectomized cyclic ewes induced endometrial expression of UCRP mRNA. These results are the first to describe temporal and spatial alterations in the cellular localization of UCRP in the ruminant uterus. Collectively, UCRP is synthesized and secreted by the ovine endometrium in response to IFNtau during early pregnancy. Because UCRP is present in the uterus and uterine flushings, it may regulate endometrial proteins associated with establishment and maintenance of early pregnancy in ruminants.

In vivo diffusion-weighted magnetic resonance microscopy of rat spinal cord: effect of ischemia and intrathecal hyperbaric 5% lidocaine

BACKGROUND AND OBJECTIVES

Pathophysiologic mechanisms underlying persistent neurologic deficits after continuous spinal anesthesia using hyperbaric 5% lidocaine are still not well understood. It has been suggested that high-dose intrathecal lidocaine induces irreversible conduction block and even ischemia in white matter tracts by breakdown of the blood-nerve barrier. In this study, we use diffusion-weighted magnetic resonance microscopy to characterize the effect of intrathecal hyperbaric 5% lidocaine in rat spinal cord. The parameter measured with DWM, is an "apparent diffusion coefficient," (ADC), which can be used to exclude the presence of ischemia.

METHODS

Female Fischer CDF rats were used. Group 1 (n = 5) was exposed to ischemia, group 2 (n = 7) was exposed to intrathecal 5% hyperbaric lidocaine, and group 3 (n = 5) was exposed to intrathecal 7.5% glucose. Diffusion-weighted MR images in group 1 were acquired before and after ischemia induced by cardiac arrest and in groups 2 and 3 rats prior to and during perfusion of the spinal catheter with either 5% hyperbaric lidocaine or 7.5% glucose.

RESULTS

Ischemia decreased the ADC by 40% in gray matter and by 30% in white matter of spinal cord. Continuous intrathecal anesthesia with hyperbaric 5% lidocaine did not affect the spinal cord ADC. Further, 7.5% intrathecal glucose had no effect on ADCs in gray or white matter of spinal cord.

CONCLUSIONS

Ischemia reduced the ADC in both spinal cord white and gray matter. Hyperbaric 5% lidocaine did not affect the spinal cord ADC during the first 1.5 hours. We suggest that 5% hyperbaric lidocaine does not induce irreversible neurologic deficits by causing spinal cord ischemia.

Endometrial ISG17 mRNA and a related mRNA are induced by interferon-tau and localized to glandular epithelial and stromal cells from pregnant cows

The interferon stimulated gene product, ISG17, conjugates to bovine uterine proteins in response to conceptus-derived interferon (IFN)-tau. The objectives of the present experiments were to examine induction of ISG17 (0.65 kb) and a related 2.5 kb mRNA in response to IFN-tau and pregnancy using Northern blotting procedures, and to determine cell types in the endometrium that expressed ISG17 mRNA using in situ hybridization. RNA was isolated from endometrial explants or from bovine endometrial (BEND) cells cultured in the absence (control) or presence of 25 nM recombinant (r) bolFN-tau for 0, 3, 6, 12, 24, or 48 h. The major ISG17 0.65 kb mRNA and a minor 2.5 kb mRNA were induced (p<0.05) after 6 h (explants) or 3 h (BEND cells) treatment with rboIFN-tau. Both mRNAs were present in endometrium from day 18 pregnant cows, but were absent in endometrium from nonpregnant cows. The ISG17 mRNA was localized to stromal and glandular epithelial cells on d 18 of pregnancy. The 2.5 kb mRNA may encode a novel ISG17 homolog, or a unique polyISG17 repeat that is similar in structure to the polyubiquitin genes. Because ISG17 mRNA is induced in stromal and glandular epithelial cells, it could be assumed that ISG17 has a role in regulating intracellular proteins in both cell types.

Magnetic resonance angiography with hyperpolarized 129Xe dissolved in a lipid emulsion

Hyperpolarized (HP) 129Xe can be dissolved in biologically compatible lipid emulsions while maintaining sufficient polarization for in vivo vascular imaging. For xenon in Intralipid 30%, in vitro spectroscopy at 2 T yielded a chemical shift of 197 +/- 1 ppm with reference to xenon gas, a spin-lattice relaxation time T1 = 25.3 +/- 2.1 sec, and a T2* time constant of 37 +/- 5 msec. Angiograms of the abdominal and pelvic veins in the rat obtained with 129Xe MRI after intravenous injection of HP 129Xe/Intralipid 30% into the tail demonstrated signal-to-noise ratios between 8 and 29. An analysis of the inflow effect on time-of-flight images of two segments of the inferior vena cava yielded additional information. The mean blood flow velocity was 34.7 +/- 1.0 mm/sec between the junction of the caudal veins and the kidneys and 13.3 +/- 0.8 mm/sec at the position of the diaphragm. The mean volume flow rates in these segments were 7.2 +/- 3.4 ml/min and 11.0 +/- 2.8 ml/min, respectively. Intravenous delivery of HP 129Xe dissolved in a carrier may lead to novel biomedical applications of laser-polarized gases.

A high-temperature superconducting Helmholtz probe for microscopy at 9.4 T

The design and operation of a high-temperature superconducting (HTS) probe for magnetic resonance microscopy (MRM) at 400 MHz are presented. The design of the probe includes a Helmholtz coil configuration and a stable open-cycle cooling mechanism. Characterization of coil operating parameters is presented to demonstrate the suitability of cryo-cooled coils for MRM. Specifically, the performance of the probe is evaluated by comparison of signal-to-noise (SNR) performance with that of a copper Helmholtz pair, analysis of B1 field homogeneity, and quantification of thermal stability. Images are presented to demonstrate the SNR advantage of the probe for typical MRM applications.

Sensitivity and resolution in 3D NMR microscopy of the lung with hyperpolarized noble gases

Three-dimensional magnetic resonance images of the guinea pig lung were acquired in vivo using hyperpolarized (HP) noble gases and radial projection encoding (PE). Results obtained with 3He (voxel size 17 microl) demonstrated high image quality showing airway structure down to the 5th or 6th generations. Signal-to-noise ratios (SNRs) of 129Xe images (voxel size 40 microl) were lower by about 1 order of magnitude as a consequence of the smaller gyromagnetic ratio, a more rapid relaxation in the gas reservoir, and lower polarization and isotope abundance. Comparison between experimentally obtained SNRs and results from calculations based on a model that accounts for the three-dimensional PE acquisition scheme and the non-equilibrium situation in HP gas imaging yielded excellent agreement for small flip angles. A theoretical examination of the potential resolution in HP gas MR microscopy of the lungs suggests that in vivo visualization of alveolar clusters distal to respiratory bronchioles may be possible.

Functional MR microscopy of the lung using hyperpolarized 3He

A new strategy designed to provide functional magnetic resonance images of the lung in small animals at microscopic resolution using hyperpolarized 3He is described. The pulse sequence is based on a combination of radial acquisition (RA) and CINE techniques, referred to as RA-CINE, and is designed for use with hyperpolarized 3He to explore lung ventilation with high temporal and spatial resolution in small animal models. Ventilation of the live guinea pig is demonstrated with effective temporal resolution of 50 msec and in-plane spatial resolution of <100 microm using hyperpolarized 3He. The RA-CINE sequence allows one to follow gas inflow and outflow in the airways as well as in the distal part of the lungs. Regional analysis of signal intensity variations can be performed and can help assess functional lung parameters such as residual gas volume and lung compliance to gas inflow.

3-Dimensional visualization of lesions in rat brain using magnetic resonance imaging microscopy

High-resolution (< 50 microm) magnetic resonance imaging microscopy (MRM) has been used to identify brain regions and localization of excitotoxin-induced lesions in fixed rat brains, subsequently confirmed using standard histology. The anatomical extent of lesions identified by MRM was identical to that seen in histological sections and various histopathological changes could be visualized. In contrast to the time involved in preparing and examining histological sections, lesions in intact brains could be rapidly identified and visualized in three dimensions by examining digitally generated sections in any plane. This study shows that MRM has tremendous potential as a prescreening tool for neurotoxicity and neuropathology. These observations suggest that MRM has the potential to affect pathology much as conventional MRI has influenced clinical imaging.

Prehospital triage and communication performance in small mass casualty incidents: a gauge for disaster preparedness

Because of their infrequency, disasters are difficult to train for. Emergency prehospital personnel frequently participate in small mass casualty incidents (MCIs) (3 to 50 victims). This study sought to examine prehospital performance in small MCIs in areas that are frequently mismanaged in disasters. Prospective data from the resource physician and retrospective data from tape recorded prehospital conversations were collected for a 9-month period. Clinical patient data, patient demographics, emergency medical services squad characteristics, and triage information were recorded. Forty-five consecutive MCIs were studied. Most of these were motor vehicle accidents. Prehospital providers included paid providers, nonpaid providers, and air and ground transport. The mean number of victims first identified (4.6%) was greatly different than the mean number of victims eventually transported from a scene (7.1%). Most patients were treated at a level 1 trauma center. Frequent errors included having multiple communicators on site (38%), misidentifying the number of victims (56%), and having unclear information for the resource physician (43%). Only 38% of events had prehospital triage information that was deemed appropriate in total. These results show that scene and triage errors are frequent in MCIs of small scale. This information can be used to assay a system's readiness for disasters.

Identification and characterization of glycosylation-dependent cell adhesion molecule 1-like protein expression in the ovine uterus

Glycosylation-dependent cell adhesion molecule 1 (GlyCAM-1) is an endothelial glycoprotein secreted in lymph nodes that serves as a ligand for leukocyte cell surface selectin and mediates lymphocyte extravasation. In the present studies, rabbit anti-rat GlyCAM-1 IgG was used in immunochemical analyses of GlyCAM-1-like protein in the ovine uterus. In cyclic ewes, GlyCAM-1 expression increased in the endometrial luminal epithelium (LE) and shallow glandular epithelium (cGE) between Days 1 and 5 and then decreased between Days 11 and 15. In pregnant ewes, GlyCAM-1 in the LE and cGE was low on Days 11 and 13, increased on Day 15, and was abundant on Days 17 and 19. Immunoreactive GlyCAM-1 was also detected in the conceptus trophectoderm on Days 13-19. Staining for GlyCAM-1 in the smooth muscle of the vasculature and myometrium was constitutive, and no staining was detected in the stroma. An immunoreactive protein of approximately 45 kDa was identified in endometrial extracts and uterine flushings from cyclic and pregnant ewes. In pregnant ewes, the relative amount of immunoreactive GlyCAM-1 in uterine flushings was low on Days 11 and 13 but high on Days 15 and 17. Results suggest that a GlyCAM-1-like protein may be a secretory product of the endometrial epithelium and/or conceptus trophectoderm. Patterns of distribution observed for immunoreactive GlyCAM-1-like protein in the endometrial epithelium, combined with proposed functions for lymphoid GlyCAM-1, suggest that this mucin glycoprotein may be involved in conceptus-maternal interactions during the periimplantation period of pregnancy in sheep.

Performance of a high-temperature superconducting probe for in vivo microscopy at 2.0 T

The use of a high-temperature superconducting probe for in vivo magnetic resonance microscopy at 2 T is described. To evaluate the performance of the probe, a series of SNR comparisons are carried out. The SNR increased by a factor of 3.7 compared with an equivalent copper coil. Quantitative measures of the SNR gain are in good agreement with theoretical predictions. A number of issues that are unique to the application of HTS coils are examined, including the difficulty in obtaining homogenous excitation without degrading the SNR of the probe. The use of the HTS probe in transmit-receive mode is simple to implement but results in nonuniform excitation. The effect of using the probe in this mode of operation on the T1 and T2 contrast is investigated. Methods for improving homogeneity are explored, such as employing a transmit volume coil. It is found that the cost of using an external transmit coil is an increased probe noise temperature and a reduced SNR by approximately 30%. Other important aspects of the probe are considered, including the effect of temperature on probe stability. Three-dimensional in vivo imaging sets are acquired to assess the stability of the probe for long scans. High-resolution images of the rat brain demonstrate the utility of the probe for microscopy applications.

Magnetic resonance imaging of embryos: an Internet resource for the study of embryonic development

The recent amassing of gene expression data to study development in mammals has led to an increased demand for access to human embryological data. The difficulty of obtaining well-preserved human embryos presents an important challenge to studying human development. The Multidimensional Human Embryo project is generating an image data set based on magnetic resonance microscopy of specimens from the highly respected Carnegie Collection of Human Embryos. The data are available from a web site to facilitate the work of clinicians, investigators, and students of human development. A consequence of the project will be to preserve a highly respected, yet impermanent, collection of human embryos and minimize the need for collecting new specimens.

A phase II trial of isotretinoin and alpha interferon in patients with recurrent squamous cell carcinoma of the cervix: a Gynecologic Oncology Group study

From January 1993 through January 1996, 37 patients with unresectable squamous carcinoma of the cervix were entered on study and scheduled to receive oral isotretinoin 1 mg/kg per day with subcutaneous alpha interferon 6,000,000 units/day. A course was defined as 4 continuous weeks of therapy. The mean number of four-course cycles delivered was 1.8. One patient was ineligible because of wrong cell type and two were never treated. Thus, 34 patients were evaluable for toxicity. Eight patients were inevaluable for response. Five did not receive a complete 4-week course and three did not have additional tumor measurements; thus 26 were evaluable for response. Prior radiotherapy had been given to 25 patients and prior chemotherapy to 23 patients. There was no grade 4 neutropenia. The incidence of Gynecologic Oncology Group (GOG) grade 3 granulocytopenia and thrombocytopenia was 8.8% and 5.8%, respectively. Six patients (17.6%) developed grade 3 or worse nausea and vomiting. Four (11.7%) patients developed grade 3 neurologic symptoms. There were no complete responses and one partial response. The overall response rate was 3.8% (95% confidence interval, 0.1-19.6%). In this pretreated population, isotretinoin and alpha interferon in the dose and schedule employed exhibit minimal activity.

Spinal cord neural anatomy in rats examined by in vivo magnetic resonance microscopy

BACKGROUND AND OBJECTIVES

Magnetic resonance microscopy (MRM) is a technique that is worthwhile for anesthesiologists because it allows spinal cord and plexus anatomy to be visualized three dimensionally and followed over time in the same animal. For example, the long-term effect of indwelling intrathecal or plexus catheters can be studied in situ, and convective and diffusive forces within intrathecal, epidural, or nerve sheath spaces can be investigated. Further, diffusion-weighted MRM, which measures an "apparent diffusion coefficient" (ADC), can be used to track the presence of ischemia, hypoperfusion, or cytotoxic edema. This study investigates problems associated with the use of in vivo MRM for spinal cord and peripheral nerve studies in the rat.

METHODS

Twenty-one anesthetized female Fisher CDF rats were used. Group 1 (n=7) was used for anatomic three-dimensional studies. Groups 2 (n=4), 3 (n=4), and 4 (n=6) were used for measurements of the ADC. Group 2 served as controls, group 3 received lumbar intrathecal catheters, and group 4 received cervical intrathecal catheters.

RESULTS

Cervical spine, lumbar spine, and spinal nerves and ganglia were accurately visualized with MRM. As a rule, spinal cord gray and white matter were better demonstrated using diffusion-weighted proton stains. By contrast, T2-weighted proton staining superiorly demonstrated structures surrounding the spinal cord. In groups 3 and 4, indwelling intrathecal catheters did not affect the spinal cord ADC, indicating normal blood flow and no cytotoxic edema. Contrast studies revealed nonhomogeneous distribution of contrast predominately in the lateral and ventral intrathecal space.

CONCLUSION

Three-dimensional diffusion-weighted MRM displays cervical and lumbar spine anatomy accurately in vivo. Apparent diffusion coefficients measurements are feasible in rat cervical spinal cord with intrathecal catheters. Spinal cord ADCs are unaffected by intrathecal catheters, indicating normal spinal cord perfusion.

Signal dynamics in magnetic resonance imaging of the lung with hyperpolarized noble gases

The nonequilibrium bulk magnetic moment of hyperpolarized (HP) noble gases generated by optical pumping has unique characteristics. Based on the Bloch equations, a model was developed describing the signal dynamics of HP gases used in magnetic resonance imaging (MRI) of the lung with special consideration to the breathing cycle. Experimental verification included extensive investigations with HP 3He and 129Xe during both inspiration and held breath in live guinea pigs. Radial acquisition was used to investigate the view variations with a temporal resolution of 5 ms. Agreement between theoretical predictions and in vivo results was excellent. Additionally, information about effects from noble gas diffusion and spin-lattice relaxation was obtained. In vivo results for T1 were 28.8 +/- 1.8 s for 3He and 31.3 +/- 1.8 s for 129Xe. Comparison with in vitro data indicated that relaxation in the pulmonary gas space is dominated by dipolar coupling with molecular oxygen. The results provide a quantitative basis for optimizing pulse sequence design in HP gas MRI of the lung.

AB-180 circulatory support system: summary of development and phase I clinical trial

The AB-180 Circulatory Support System (AB-180 CSS; Cardiac Assist Technologies, Pittsburgh, PA) is a left ventricular assist system for investigational use in patients with postcardiotomy cardiogenic shock who are refractory to standard treatment with an intra-aortic balloon pump, pharmacologic treatment, or both. The intent of the AB-180 CSS is to provide temporary (up to 14 days) mechanical circulatory support until the heart recovers adequate mechanical function. The system consists of a small implantable centrifugal pump and a controller. A unique infusion system produces a hydrodynamic bearing between rotational and stationary components of the AB-180 CSS pump. This infusion system also provides a source of heparin for localized anticoagulation. Extensive bench and animal work has illustrated anticoagulation requirements, established operating guidelines, and demonstrated safety and efficacy. An investigational device exemption has been granted for a Phase I, five patient feasibility study at Allegheny General Hospital in Pittsburgh, Pennsylvania. To date, the pump has been implanted in one patient. The results from this first case are presented here.

In vivo magnetic resonance vascular imaging using laser-polarized 3He microbubbles

Laser-polarized gases (3He and 129Xe) are currently being used in magnetic resonance imaging as strong signal sources that can be safely introduced into the lung. Recently, researchers have been investigating other tissues using 129Xe. These studies use xenon dissolved in a carrier such as lipid vesicles or blood. Since helium is much less soluble than xenon in these materials, 3He has been used exclusively for imaging air spaces. However, considering that the signal of 3He is more than 10 times greater than that of 129Xe for presently attainable polarization levels, this work has focused on generating a method to introduce 3He into the vascular system. We addressed the low solubility issue by producing suspensions of 3He microbubbles. Here, we provide the first vascular images obtained with laser-polarized 3He. The potential increase in signal and absence of background should allow this technique to produce high-resolution angiographic images. In addition, quantitative measurements of blood flow velocity and tissue perfusion will be feasible.

Complex induction of bovine uterine proteins by interferon-tau

Interferon-tau (IFN-tau) is released by the conceptus and induces two uterine proteins during early pregnancy: ubiquitin cross-reactive protein (UCRP) and granulocyte chemotactic protein-2 (GCP-2). The present experiments were designed to determine whether detection (Western blot) of cytosolic UCRP and release of GCP-2 could be used to examine IFN-tau signal transduction in cultured endometrial explants and primary epithelial cells. Recombinant (r) type 1 IFNs (rboIFN-tau and rboIFN-alpha; 5, 25, 100 nM) induced UCRP, but only rboIFN-tau induced GCP-2 in explant culture. Recombinant boIFN-tau and conceptus secretory proteins containing native IFN-tau induced UCRP and GCP-2 in cultured primary epithelial cells. All concentrations of rboIFN-alpha (25, 50, 100 nM) induced UCRP, but only the highest concentration induced GCP-2 in cultured primary epithelial cells. Interestingly, phorbol ester (100, 500, 1000 ng/ml) induced GCP-2, but it had no effect on UCRP. Because type 1 IFNs induce UCRP, IFN-tau probably interacts with the janus kinase (Jak)-associated IFN-alpha receptor to phosphorylate signal transducers and activators of transcription (STAT) and/or interferon regulatory factor-1 (IRF-1). However, IFN-tau-specific induction of GCP-2 may involve a variant type 1 receptor subunit or activators of transcription that are associated with protein kinase C and the Jak/STAT/IRF-1 pathway.

Hyperpolarized 3He NMR lineshape measurements in the live guinea pig lung

Spatially localized lineshapes of hyperpolarized (HP) 3He in guinea pig lungs have been measured in vivo. Three different axial slice locations, each containing different compositions of airway sizes and orientations, were studied. Gas peaks from major bronchi (2 ppm) and alveoli (-2 ppm) were distinguished. The gas phase spectra show structural features that are a result of frequency shifts caused by bulk magnetic susceptibility. For a given slice, the spectral lineshapes reflect the airway composition within the slice location, according to theory. The peak assignments given here also agree with previous studies done by Wagshul et al. with HP 129Xe. At each of the slice locations, data were acquired during two phases of the breathing cycle, resulting in a relative frequency shift of approximately 0.3 ppm in the superior slices. Spectra obtained over a number of breaths show the dynamics of the gas buildup in the lung and provide further evidence supporting the peak assignments.

Measuring the progression of foreign-body reaction to silicone implants using in vivo MR microscopy

We used in vivo magnetic resonance (MR) microscopy to follow the growth of fibrous capsule as a foreign body reaction to silicone implants in rats. Anesthetized rats were imaged 1, 7, 14, and 28 days after silicone-coated MR imaging coils were sutured to their neck muscles. On the twenty-eighth day, rats were sacrificed and coils and adjacent tissues were removed en bloc and fixed in formalin, reimaged with MR, and sectioned for conventional histology. Three-dimensional (3-D) spin-echo [3DFT] acquisition gave in-plane resolution of 32 x 32 microns in vivo and 16 x 16 microns ex vivo. All MR images showed a diffuse band of elevated signal intensity between the silicone of the coil and adjacent tissue. The border of the hyperintense band was thin and not well defined at seven days post-implantation. From 7-28 days, the band showed relatively homogeneous signal intensity and its thickness increased 44% on the rectus muscle side and 78% on the subcutaneous side. The capsule thickness determined either by MR in vivo and ex vivo microscopy or conventional histology was not significantly different, and there was a significant correlation between thickness measurements among those methods. MR in vivo microscopy provides sufficient resolution and spatial information to serially evaluate the growth of the foreign body fibrous capsule over time, thus achieving greater accuracy and consistency in measurements.

Time-course imaging of rat embryos in utero with magnetic resonance microscopy

Magnetic resonance (MR) microscopy was used to noninvasively investigate the development of live rat embryos in utero. The difficulty in making sequential observations of a developing mammalian embryo has frustrated developmental biologists for many years. Most current technologies analyze normal and abnormal development by observing end point phenotypes (in fixed specimens) rather than investigating the live embryo. MR microscopy was adapted to allow rat litters to be scanned three times each (at 1- to 3-day intervals) and has produced images of live developing embryos. It was demonstrated that repeated anesthesia and imaging protocols produced no gross malformations in the rat pups that were subsequently delivered and observed. Three-dimensional projection encoding with phase rewinders produced isotropic [256(3)] image data sets in about 30 minutes with excellent tissue contrast arising from steady-state effects in the amniotic fluid.