Testicular damage after surgical groin exploration for elective herniorrhaphy

BACKGROUND/PURPOSE

Controversy exists whether to explore the contralateral groin in boys during unilateral herniorrhaphy. Proponents claim there is minimal risk of injury to the cord structures and developing testicle with contralateral exploration. However, findings have shown testicular atrophy occurred in 1% to 2% of patients after herniorrhaphy, and vasal damage is possible after routine manipulation of the spermatic cord. This study investigated the effect of routine surgical exploration of the prepubertal groin on testicular development and future fertility.

METHODS

Twenty-four prepubertal Wistar rats were divided equally into 2 groups. Group 1 (sham) rats underwent unilateral inguinoscrotal incision only. Group 2 (experimental) rats underwent unilateral inguinoscrotal exploration with manipulation of the cord structures as in human inguinal exploration. At maturation, the fertility and fecundity of the males were assessed. After mating, testes were examined for mass, volume, mean seminiferous tubule diameter (MSTD), and mean testicular biopsy score (MTBS). The vasa were examined for histological injury and vasal diameter. Statistical comparisons were made by paired t test and Mann-Whitney rank sum test.

RESULTS

There was a difference between the volumes of the testes when comparing the operative and nonoperative side of the 2 groups (experimental, deltavol = -0.063+/-0.123; sham, deltavol = +0.067+/-0.137; P = .029). There also was a trend toward a smaller testicular mass when comparing the two sides (experimental, deltamass = -0.045+/-0.101; sham, Amass = +0.048+/-0.123; P = .057) but did not reach significance. The MSTD and MTBS were similar between the ipsilateral and contralateral testes in both groups. Likewise, the MSTD and MTBS were similar when comparing the 2 groups. All male rats in both groups were fertile. The number of offspring produced and the number of female rats impregnated were similar between the 2 groups. There was no histological evidence of vasal injury in any of the experimental spermatic cords. The vasal diameters were similar between the 2 groups.

CONCLUSION

Surgical manipulation of the prepubertal spermatic cord imparts a small, but statistically significant morphological change in testicular size without a deleterious effect on testicular development, fertility, or fecundity.

Serum CTX: a new marker of bone resorption that shows treatment effect more often than other markers because of low coefficient of variability and large changes with bisphosphonate therapy

Serum CrossLaps is a new assay for measuring carboxy-terminal collagen crosslinks (CTX) in serum. This measurement is reported to be more specific to bone resorption than other measurements. However, the utility of this and other markers in monitoring patients on antiresorptive therapy depends on how often changes anticipated with therapy exceed changes attributable to random variability. In a study where subjects received either placebo or pamidronate, we calculated the minimum significant change (MSC), that is, the change that was sufficiently large that it was unlikely to be due to spontaneous variability. We also examined the changes in markers of bone turnover in subjects treated with pamidronate (APD) (30 mg i.v. in 500 ml D5W over 4 hours) to see how often observed changes in turnover after treatment exceeded the MSC. The MSC for serum CTX was 30.2%, and was significantly (P < 0.05) lower than the MSC for urinary NTX (54.0%), and not significantly different from the MSC of urinary DPD (20.6%). Ninety percent of subjects treated with APD had a decline in serum CTX that exceeded the MSC, compared with 74% for bone-specific alkaline phophatase (BSAP), 57% for urinary N-telopeptide cross-links (NTX), and 48% for free deoxypyridinoline. Changes in serum CTX correlated reasonably well with changes in spine BMD after 2 years (r = 0.47), but this correlation did not quite reach statistical significance because of the small number of subjects. In conclusion, the serum CTX assay shows greater utility for assessing efficacy of antiresorptive treatment than some previously described markers.

Production and molar yield of 2-phenylethanol by Pichia fermentans L-5 as affected by some medium components

In this study, the effects of carbon sources and various levels of sucrose (0-30%) yeast extract (0-1.25%) and phenylalanine (0-0.2%) on the production of 2-phenylethanol by Pichia fermentans L-5 were investigated. Results revealed that among the 11 carbon sources tested, glycerol and sucrose were suitable carbon sources for P. fermentans L-5 resulting in production of higher amounts of 2-phenylethanol. In the medium that contained 18% sucrose, P. fermentans L-5 produced the highest amount of 2-phenylethanol, 283.4 mg/l with a molar yield of 0.77, was noted among the various levels of sucrose tested. Increasing the amount of phenylalanine added to the culture medium to 1.0% resulted in increased production of phenylethanol. Enhanced production of 2-phenylethanol, 453.1 mg/l by P. fermentans L-5 with a molar yield of 0.71 for phenylethanol was obtained in the medium containing 18% sucrose, 0.25% yeast extract and 0.1% phenylalanine after 16 h of fermentation.

Interaction between developmental and cell cycle regulators is required for morphogenesis in Aspergillus nidulans

In Aspergillus nidulans, mutation of the transcriptional regulator brlA arrests formation of asexual spore-forming structures called conidiophores but does not hinder vegetative hyphal growth. During conidiophore development a 6-fold, brlA-dependent increase in the kinase activities of NIMX(cdc2) and NIMA occurs. A similar level of kinase induction was promoted by ectopic expression of brlA. Northern and Western analysis revealed marked induction of nimX(cdc2) mRNA after ectopic expression of brlA and increased amounts of NIMX(cdc2). Therefore, nimX(cdc2) is developmentally regulated by brlA indicating a direct role for brlA in the regulation of cell cycle genes. That correct regulation of nimX(cdc2) is important for normal development was further supported by analysis of conidiophore development and septation in cell cycle specific mutants. Most noticeably, the nimX(cdc2AF) mutation promoted inappropriate septation and hindered the switch from filamentous growth to budding growth seen during conidiophore development. Therefore, in contrast to the situation previously reported for other multicellular eukaryotes, interaction between developmental regulators and cell cycle regulators is essential for normal morphogenesis in A.nidulans.

Characterization of the mUBC9-binding sites required for E2A protein degradation

Mammalian Ubc9 (mUbc9) is required for rapid degradation of the E2A proteins E12 and E47 by the ubiquitin-proteasome system. We have shown elsewhere that mUbc9 interacts with amino acids 477-530 of E12/E47. Here we test the hypothesis that this region, rich in proline, glutamic acid, serine, and threonine (PEST) residues, serves as the E2A protein degradation domain (DD). An E2A protein lacking this region, E47Delta(478-531), was significantly more stable than wild-type E47(half-life of more than 6 h versus 55 min). Deletion of the E2A DD had no effect on the E-box-binding and transcriptional activity of E47. We mapped two discreet mUbc9-interacting regions within the E2A DD: amino acids 476-494 and 505-513. E2A(505-513) interacted with mUbc9 but not with human Ubc5, MyoD, Id3, or the polymyositis-scleroderma autoantigen. Substitution of the E2A(505-513) central hydrophobic residues with basic residues abolished interaction with mUbc9. Also, full-length E47 lacking the second mUbc9-interacting region was significantly more stable than wild-type E47. Reintroduction of the E2A DD into the long-lived, naturally occurring chimeric oncoprotein E2A-HLF (hepatic leukemic factor) destabilized it, suggesting that this domain can transfer a degradation signal to a heterologous protein. E2A-HLF-DD chimeric protein was stabilized by the proteasome inhibitor LLNL, indicating the role of the ubiquitin-proteasome system mediating degradation through the E2A degradation domain. Our experiments indicate that the E2A DD mediates E2A protein interactions with the ubiquitin-proteasome system and that the E2A DD is required for metabolism of these widely expressed proteins.

Expression of mRNAs encoding full-length and truncated TrkB receptors in rat dorsal root ganglia and spinal cord following peripheral inflammation

Peripheral inflammation induces an increased brain-derived neurotrophic factor (BDNF) synthesis in the dorsal root ganglion (DRG) and an elevated anterograde transport of BDNF to axon terminals in the spinal dorsal horn. To characterize whether expression of trkB is modulated in response to BDNF elevation in these areas, we evaluated changes in expression of full-length and truncated trkB (trkB.FL and trkB.T) mRNAs after injection of complete Freund's adjuvant into the hind paw of the rat. Reverse transcription-polymerase chain reaction analysis revealed that BDNF and trkB.T mRNAs levels in the DRG increased, while no change of expression of trkB.FL mRNA was observed. There was no detectable change in both trkB.FL and trkB.T mRNAs levels in the spinal cord. Considering that trkB.T mRNA is expressed mainly in the perineuronal satellite cells, these results suggest a possible paracrine role of BDNF within the DRG in addition to an important role related with nociception following peripheral inflammation.

Perihepatic packing of major liver injuries: complications and mortality

HYPOTHESIS

Perihepatic packs used to control hemorrhage after liver injury increase the risk of complications and this risk increases the longer packs are left in place.

DESIGN

Retrospective case series.

SETTING

University level I trauma center.

PATIENTS

Consecutive patients with hepatic injury.

MAIN OUTCOME MEASURES

Liver-related complications (biliary leak and abscess), rebleeding, and mortality.

RESULTS

One hundred twenty-nine of 804 patients with liver injuries were treated with perihepatic packing. Of the 69 who survived more than 24 hours, 75% lived to hospital discharge. Mortality rates were 14% and 30% in patients with and without liver complications, respectively (P = .23). Liver complication rates were similar (P = .83) when packs were removed within 36 hours (early [33%]) or between 36 and 72 hours (late [29%]) after they were placed; the rebleeding rate was greater in the early group (21% vs 4%; P<.001).

CONCLUSIONS

Liver complications associated with perihepatic packing did not affect survival. Removing liver packs 36 to 72 hours after placement reduced the risk of rebleeding without increasing the risk of liver-related complications.

Acute cholecystitis secondary to hemobilia

Invasive diagnostic and therapeutic techniques such as percutaneous transhepatic cholangiography, endoscopic retrograde cholangiopancreatography (ERCP), transjugular intrahepatic portosystemic shunting, and laparoscopic cholecystectomy have led to a rise in hemobilia. Most complications from hemobilia are attributable to acute blood loss; other complications are secondary to thrombus formation in the biliary tree. We present a case report of acute cholecystitis secondary to hemobilia after percutaneous liver biopsy. The role of ERCP in the diagnosis and treatment of this exceedingly rare event is discussed.

Serotonin stimulates mitogen-activated protein kinase activity through the formation of superoxide anion

Our previous studies have shown that, through an active transport process, serotonin (5-HT) rapidly elevates O(-)(2). formation, stimulates protein phosphorylation, and enhances proliferation of bovine pulmonary artery smooth muscle cells (SMCs). We presently show that 1 microM 5-HT also rapidly elevates phosphorylation and activation of the mitogen-activated protein (MAP) kinases extracellular signal-regulated kinase (ERK) 1 and ERK2 of SMCs, and the enhanced phosphorylation is blocked by the antioxidants Tiron, N-acetyl-L-cysteine (NAC), and Ginkgo biloba extract. Inhibition of MAP kinase with PD-98059 failed to block enhanced O(-)(2). formation by 5-HT. Chinese hamster lung fibroblasts (CCL-39 cells), which demonstrate both 5-HT transporter and receptor activity, showed a similar response to 5-HT (i.e., enhanced mitogenesis, O(-)(2). formation, and ERK1 and ERK2 phosphorylation and activation). Unlike SMCs, they also responded to 5-HT receptor agonists. We conclude that downstream signaling of MAP kinase is a generalized cellular response to 5-HT that occurs secondary to O(-)(2). formation and may be initiated by either the 5-HT transporter or receptor depending on the cell type.

Behavioural responses of cockerels to semen collection and their influence on semen characteristics

One-hundred-and-twenty cockerels of Strain L2 Taiwan Country chicken from the National Chung-Hsing University were tested for their behavioural responses to semen collection at 21 to 30, 34 to 43 and 57 to 66 weeks of age. At every age period, semen was collected from every cockerel 4 times within a 1-week period. 2. Cockerel performances on most semen traits, including volume, concentration, total number of sperm, ease of collection and sensitivity to massage were very consistent within each age period. 3. Males that did not respond nervously to handling or were less sensitive to massage appeared to produce less semen. However, contamination was more serious in males that responded very nervously or were very sensitive to massage. 4. Sensitivity to massage, like semen volume, is an invariant character as indicated by the high correlation between measures taken at different age periods.

Reduction of endothelial cell related TGFbeta activity by thiols

Transforming growth factor beta (TGFbeta) may play an important role in diseases characterized by pulmonary fibrosis. We have previously demonstrated that thiols inhibit the pro-oxidant effects of TGFbeta1 in bovine pulmonary artery endothelial cells (BPAEC). To help define the mechanism of this observation we have examined the effect of reduced (GSH) and oxidized (GSSG) glutathione, N-acetyl cysteine (NAC) and cysteine (CYS) on the biological activity of a) TGFbeta released by bovine pulmonary artery endothelial cells (BPAEC) into culture medium, and b) commercially available porcine platelet TGFbeta1. The biological activity of TGFbeta (following activation) released into the medium from cultured BPAEC was significantly reduced when the cells were cultured in the presence of 10 mM GSH or 10 mM NAC for 24 h (10 mM GSH: 85.7 +/- 50 pg/ml/10(6) cells and 10 mM NAC: 127.3 +/- 35 pg/ml/10(6) cells, compared with control: 541 +/- 8.9 pg/ml/10(6) cells; p < 0.05). Thiols (10 mM GSH, 10 mM NAC and 5 mM cysteine), added directly to cell-free conditioned medium or to a commercially available preparation of porcine platelet TGFbeta1 for 6-24 h had a similar inhibitory effect on the biological activity of TGFbeta and altered the structure of porcine platelet TGFbeta1 as determined by mass spectroscopy. These thiols failed to reduce the expression of TGFbeta mRNA in BPAEC as measured by a competitive polymerase chain reaction assay. Incubating endothelial cells or cell-free conditioned medium with GSSG did not alter the biological activity of TGFbeta. Lower doses of thiols (0.1-1 mM), that we have shown inhibit the antiproliferative and pro-oxidant effects of exogenous TGFbeta1 on BPAEC, had no direct effect on TGFbeta bioactivity. In summary, thiols are capable of reducing the effects of TGFbeta in biological systems through a direct effect on the TGFbeta molecule. However, this action appears to be dose-dependent, and at low doses (0.1-1 mM) thiols may also inhibit the actions of exogenous TGFbeta1 in cell culture through a mechanism involving the cellular redox status.

Too much versus too little: the implications of current iodine intake in the United States

Iodine intake influences the health of Americans today, but in different ways than it has in the past. In the early 1900s, iodine deficiency was responsible for widespread endemic goiter in the United States. The incidence of goiter was markedly reduced by the introduction of iodine supplementation of salt and other foods in the 1920s. By the middle of this century iodine-related problems in the Unites States were more likely to be associated with too much rather than too little of this essential nutrient. Recent and disturbing new data suggest that there has been a sharp decline in iodine intake during the last 20 years, especially in women of reproductive age. A brief comparison of thyroid response to insufficient and excessive intakes in normal and diseased thyroid tissue is presented. The population affected and the implications for therapy are also reviewed.

p53 deficiency rescues the adverse effects of telomere loss and cooperates with telomere dysfunction to accelerate carcinogenesis

Maintenance of telomere length and function is critical for the efficient proliferation of eukaryotic cells. Here, we examine the interactions between telomere dysfunction and p53 in cells and organs of telomerase-deficient mice. Coincident with severe telomere shortening and associated genomic instability, p53 is activated, leading to growth arrest and/or apoptosis. Deletion of p53 significantly attenuated the adverse cellular and organismal effects of telomere dysfunction, but only during the earliest stages of genetic crisis. Correspondingly, the loss of telomere function and p53 deficiency cooperated to initiate the transformation process. Together, these studies establish a key role for p53 in the cellular response to telomere dysfunction in both normal and neoplastic cells, question the significance of crisis as a tumor suppressor mechanism, and identify a biologically relevant stage of advanced crisis, termed genetic catastrophe.

A study of adult T-cell leukemia/lymphoma incidence in central Brooklyn

Adult T-cell leukemia/lymphoma (ATL), a rare outcome of infection with human T-lymphotropic virus (HTLV-I), is endemic in central Brooklyn, which has a large Caribbean migrant population. Previous studies have suggested that HTLV-I prevalence in central Brooklyn may be similar to that recorded in the Caribbean islands. We established a pilot 1-year surveillance program to identify cases of ATL in 7 of 10 hospitals serving the residents of 18 zip codes of central Brooklyn with a combined population of 1,184,670. Of the 6,198 in-patient beds in the catchment area, approximately 83% were covered. Twelve incident cases of ATL were ascertained, all among persons of Afro-Caribbean descent, indicating an annual incidence in African-Americans in this community of approximately 3.2/100,000 person-years. Unexplained hypercalcemia was the most useful screening method, identifying 3 of 5 patients not referred for possible ATL by a local hematologist. The female:male ratio was 3:1. The age pattern was different from that reported in the Caribbean Basin and closer to the pattern seen in Japan. Our study supports evidence that HTLV-I infection and ATL are endemic in central Brooklyn and suggests that a more intensive surveillance program for this disease coupled with intervention efforts to reduce HTLV-I transmission are warranted.

Multiscale curvature-based shape representation using B-spline wavelets

This paper presents a new multiscale curvature-based shape representation technique with application to curve data compression using B-spline wavelets. The evolution of the curve is implemented in the B-spline scale-space, which enjoys a number of advantages over the classical Gaussian scale-space, for instance, the availability of fast algorithms. The B-spline wavelet transforms are used to efficiently estimate the multiscale curvature functions. Based on the curvature scale-space image, we introduce a coarse-to-fine matching algorithm which automatically detects the dominant points and uses them as knots for curve interpolation.

Phase-domain processing of optical coherence tomography images

In optical coherence tomography (OCT), images are usually formed from the envelope of the measured interference signal. Computation of the absolute magnitude of the signal for measurement of the envelope is a nonlinear process that destroys phase information. This study explores the idea of recording and processing the phase of the OCT interference signal before calculation of the magnitudes for display. Processing the partially coherent OCT signals in the complex domain provides the opportunity to correct phase aberrations responsible for speckle noise in OCT images. We describe an OCT system that incorporates a quadrature-demodulation scheme for accurate recording of the phase and amplitude of OCT signals from single or multiple detectors. A speckle-reduction technique that works in the complex domain, called the zero-adjustment procedure (ZAP), is investigated as an example of complex-domain processing. After demonstrating its speckle-correction properties mathematically and in numerical simulations, we apply ZAP to OCT images of living skin. The results show that ZAP reduces speckle contrast in regions where scatterer density is high and expands the range of gray values in the image. However, as presently implemented, ZAP tends to blur sharp boundaries between image features. © 1999 Society of Photo-Optical Instrumentation Engineers.

Post-therapy iodine-131 localization in unsuspected large renal cyst: possible mechanisms

Sensitive and specific, whole-body 131I scintigraphy remains an important technique for diagnosing metastases from differentiated papillary or follicular thyroid carcinoma. False-positive 131I localization is well recognized and can occur in a variety of conditions. We present a case of intense 131I localization in a previously unsuspected large renal cyst; the lesion was not visualized on routine preablation diagnostic 131I scintigraphy but was obvious on post-therapeutic whole-body imaging, underscoring the value of post-therapy imaging in detecting abnormalities not apparent on diagnostic studies. Radioiodine within the urinary bladder or, at times, the renal collecting system is expected, because 131I excretion is primarily by glomerular filtration. In the case presented here, 131I activity within the renal cyst supports the concept that iodide is subject to an active secretory process by the renal tubule.

Utility of biochemical markers of bone turnover in the follow-up of patients treated with bisphosphonates

Biochemical markers of bone turnover are often measured in patients treated with antiresorptive agents to monitor the effects of therapy. In order for a change in these markers to clearly indicate treatment effect, the change in the markers must exceed the amount of spontaneous variation typically seen with no treatment. Based on the measured long-term variability of markers in untreated patients, we defined a minimum significant change (MSC), that is, a change that was sufficiently large that it was unlikely to be due to spontaneous variability. We also examined the changes in markers of bone turnover in subjects treated with pamidronate to see how often observed changes in turnover after treatment exceeded the MSC. We found that urinary markers of bone resorption are best measured on 2-hour fasting samples, because results on random urine showed poor precision and less decline with therapy. We also found that of all the markers, urinary N-telopeptide cross-links (NTX) had the greatest decline after therapy (58%), although it also had the highest long-term variability (29.5%). The marker that most often showed a decline with treatment that exceeded the MSC was serum bone-specific alkaline phosphatase where 74% of observed changes exceeded the MSC. Other markers that often showed a decline with treatment that exceeded the MSC were 2-hour fasting urine NTX and free deoxypyridinoline, where 57% and 48%, respectively, of changes in therapy exceeded the MSC. The ideal marker would combine the large decline after treatment characteristic of NTX (60-70%) with the good precision of bone-specific alkaline phosphatase.

Epidemiology of bovine ephemeral fever virus infection in Taiwan

Sick animals with excessive nasal discharges and protruding tongue as a result of dyspnea were observed in the August of 1996. Eight strains of BEF virus were isolated from heparinized blood samples of the affected cattle. Most of the affected cattle were difficult to be treated and had a poor prognosis. A total of 516 farms in the 9 districts of Taiwan were affected in 1996. Among a population of 110,247 dairy cattle, 14,993 (13.6%) cattle were found to be clinically ill. During the epidemic, 1,685 (11.3%) affected cattle were culled or dead after the onset of the disease. Furthermore, a strain of Ibaraki virus was isolated from the blood sample of a sick cattle that showed pyrexia, labored respiration and solitary behavior in the affected farm. The cattle with Ibaraki virus infection had typical symptoms of BEF at the early stage of the disease, but neither stomatitis nor pharyngoesophageal paralysis was observed at the onset of the disease. The outbreak was presumably brought about by the low level or non-immune status of a large cattle population due to the negligence of BEF vaccination. Therefore, the disease easily recurred in Taiwan after a typhoon episode in the August of 1996, which resulted in the proliferation of biting midges in the field. No difference in the antigenicty was found between the new and the previous isolates of BEF virus. As analyzed by cross neutralization test, the isolated BEF viruses showed no relationship to the Kimberley and Berrimah viruses that were isolated from the blood of cattle and related to BEF virus in Australia. We have tried to advise farmers that they must vaccinate their cattle annually to prevent BEF outbreak in the future.

Superoxide scavenging effect of Ginkgo biloba extract on serotonin-induced mitogenesis

We have reported previously that serotonin (5-HT) stimulates the mitogenesis of bovine pulmonary artery smooth muscle cells (SMCs) through active transport of 5-HT and cellular signaling that includes elevation of superoxide (O2.-) and enhancement of protein tyrosine phosphorylation. Ginkgo biloba extract 501 (EGb 501), which has been demonstrated to act as an antioxidant, was found to block both the elevated O2.- and the proliferative and hypertrophic influences of 5-HT on SMCs, but not to directly inhibit the associated activation of NAD(P)H oxidase or the stimulation of phosphorylation of GTPase-activating protein (GAP). A similar effect of Ginkgo biloba extract 501 occurred on Chinese hamster lung fibroblasts (CCL-39), where 5-HT receptor, as opposed to transporter, action has been associated with mitogenesis. We conclude from these studies that Ginkgo biloba extract 501 quenches O2.- formation by 5-HT, thereby blocking its mitogenic effect. Stimulation of protein tyrosine phosphorylation of GAP by 5-HT appears to precede the elevation of O2.-.

Characterization of the circadian system of NGFI-A and NGFI-A/NGFI-B deficient mice

The genes NGFI-A (also known as EGR-1, zif/268, and Krox-24) and NGFI-B (nur/77) have previously been shown to be induced in the SCN of rats and hamsters by photic stimulation during the subjective night. The purpose of this study is to determine whether these genes are also induced in the SCN of mice and, if so, to characterize the circadian system of animals in which either NGFI-A or both NGFI-A and NGFI-B were eliminated by homologous recombination. In wildtype mice, NGFI-A mRNA was found to be induced in the SCN as in other rodent species. Therefore, wheel-running activity was recorded from null mutants and wildtype controls under LD 12:12 and DD conditions. Mice of all three strains appeared to entrain normally to LD 12:12 and could re-entrain to both phase advances and phase delays of the light cycle. The response of the circadian pacemaker of all three genotypes to acute light pulses appeared to be normal. The retinal innervation of the SCN in NGFI-A-/- mice and the photic induction of Fos in the SCN of both NGFI-A-/- and NGFI-A-/-/B-/- mice were indistinguishable from wildtype mice. These results indicate that induction of NGFI-A and NGFI-B is not required for photic entrainment or phase shifting of the mouse circadian system.

Tissue factor transcription driven by Egr-1 is a critical mechanism of murine pulmonary fibrin deposition in hypoxia

Local hypoxemia and stasis trigger thrombosis. We have demonstrated previously that in a murine model of normobaric hypoxia pulmonary fibrin deposition is a result of expression of tissue factor, especially in oxygen-deprived mononuclear phagocytes (MPs). We now show that transcription factor early-growth-response gene product (Egr-1) is rapidly activated in hypoxia, both in vitro and in vivo, and is responsible for transcription and expression of tissue factor in hypoxic lung. MPs and HeLa cells subjected to hypoxia (pO2 approximately 13 torr) had increased levels of tissue factor transcripts (approximately 18-fold) and an increased rate of transcription (approximately 15-fold), based on nuclear run-on analysis. Gel-shift analysis of nuclear extracts from hypoxic MPs and HeLa cells demonstrated increased DNA-binding activity at the serum response region (SRR; -111/+14 bp) of the tissue factor promoter at Egr-1 motifs. Using 32P-labeled Egr consensus oligonucleotide, we observed induction of DNA-binding activity in nuclear extracts from hypoxic lung and HeLa cells because of activation of Egr-1, by means of supershift analysis. Transient transfection of HeLa cells with chimeric plasmids containing wild-type or mutant SRR from the tissue factor promoter showed that intact Sp1 sites are necessary for basal promoter activity, whereas the integrity of Egr-1 sites was required for hypoxia-enhanced expression. A central role for Egr-1 in hypoxia-mediated tissue factor expression was confirmed by experiments with homozygous Egr-1 null mice; wild-type mice subjected to oxygen deprivation expressed tissue factor and showed fibrin deposition, but hypoxic homozygous Egr-1 null mice displayed neither tissue factor nor fibrin. These data delineate a novel biology for hypoxia-induced fibrin deposition, in which oxygen deprivation-induced activation of Egr-1, resulting in expression of tissue factor, has an unexpected and central role.

Randomized trial of pamidronate in patients with thyroid cancer: bone density is not reduced by suppressive doses of thyroxine, but is increased by cyclic intravenous pamidronate

Patients taking suppressive doses of T4 are thought to have accelerated bone loss and increased risk of osteoporosis. We therefore randomize 55 patients taking suppressive doses of T4 to treatment with pamidronate (APD) 30 mg i.v. every 3 months for 2 yr (APD/T4), or placebo (placebo/T4). Patients had measurements of bone mineral density (BMD) of the spine, hip, radius, and total body every 6 months for 2 yr. There was no significant bone loss at any site in the placebo/T4 group. Ninety five percent confidence intervals excluded a rate of bone loss > 0.89%/yr for the spine and > 0.31%/yr at the total hip. When men were excluded from the analysis, there still was no significant bone loss for the placebo/T4 group, and confidence intervals did not change. The APD/T4 group showed increases in spine (4.3%, P = 0.0001), total hip (1.4%, P < 0.05), and trochanteric (3.0%, P = 0.0001) BMDs. In conclusion, premenopausal women and men on suppressive therapy with T4 do not lose bone rapidly, and are not at increased risk of developing osteoporosis. A regimen of 30 mg APD given every 3 months for 2 yr causes significant suppression of bone resorption and increases in BMD, and may be an acceptable alternative treatment for osteoporosis in patients who cannot tolerate oral bisphosphonates.

Thy-1, a novel marker for angiogenesis upregulated by inflammatory cytokines

We identified the cell surface glycoprotein Thy-1 on the endothelium of newly formed blood vessels in four models of angiogenesis in adult rats. Anti-Thy-1 staining showed that Thy-1 was upregulated in adventitial blood vessels after balloon injury to the carotid artery. Preabsorption with a rat Thy-1-Ig fusion construct eliminated all immunoreactivity and thus confirmed the specificity of the Thy-1 staining. Thy-1 was also expressed in the endothelium of small blood vessels formed after tumor implantation in the cornea, in periureteral vessels formed after ligation of the renal artery, and in small blood vessels of the uterus formed during pregnancy. In contrast with its expression during adult angiogenesis, Thy-1 was not expressed in the endothelium of blood vessels during embryonic angiogenesis. In vitro, the inflammatory cytokines interleukin-1beta and tumor necrosis factor-alpha upregulated Thy-1 mRNA by 8- and 14-fold, respectively. Vascular endothelial growth factor, basic fibroblast growth factor, transforming growth factor-beta, and platelet-derived growth factor-BB had no effect on Thy-1 mRNA. Thus, Thy-1 appears to be a marker of adult but not embryonic angiogenesis. The upregulation of Thy-1 by cytokines but not growth factors indicates the importance of inflammation in the pathogenesis of adult angiogenesis.

Superoxide as an intermediate signal for serotonin-induced mitogenesis

Serotonin (5-HT) stimulates tyrosine phosphorylation and proliferation of bovine pulmonary artery smooth muscle cells (SMC) through its active transport (Lee et al, 1991). The present studies show that 5-HT also rapidly elevates O2.- formation by these cells within 10 minutes as measured by a lucigenin-enhanced chemiluminescence assay. The O2.- free radical quencher, Tiron, and N-acetyl-cysteine, a substrate for glutathione, block both the 5-HT-induced formation of O2.- and cellular proliferation. Similarly, inhibition of 5-HT transport with imipramine or treatment of cells with diphenyliodonium, a NAD(P)H oxidase inhibitor, block both 5-HT-induced elevation of O2.- and cellular proliferation. Alpha-hydroxyfarnesylphosphonic acid, an inhibitor of p21ras, also blocks 5-HT-induced proliferation. Endothelial cells from the same vessel show neither 5-HT-induced proliferation nor stimulation of O2.- formation. We conclude that 5-HT induced cellular proliferation of SMC through signaling pathways that utilize its transport system and O2.- formation.

Toxic nodular goiter. Toxic adenoma and toxic multinodular goiter

Solitary toxic adenoma and toxic multinodular goiter are very common forms of thyrotoxicosis around the world. Advances in molecular biology and genetics have led to new insights into the pathogenesis of these disorders. Current theories on autonomy in the thyroid are discussed in this article. The therapeutic roles of surgery, radioiodine ablation, and percutaneous ethanol administration also are reviewed.

Molecular cloning of a novel potassium-dependent sodium-calcium exchanger from rat brain

We have isolated a novel cDNA clone from rat cerebral cortex encoding a protein of 670 amino acids (NCKX2) that has significant similarity to the 1199-amino acid-long Na/Ca-K exchanger of bovine rod outer segment (NCKX1). NCKX2 transcripts are 10.5 kilobase pairs in length and are expressed abundantly in neurons throughout the brain and with much lower abundance in selected other tissues. The predicted topology of the rat NCKX2 protein is very similar to that of bovine NCKX1, beginning with a solitary transmembrane segment (M0), which is removed as a "signal peptide" in bovine NCKX1, an extracellular loop, a cluster of five transmembrane spanning segments (M1 to M5), a long cytoplasmic loop, and a final hydrophobic cluster (M6 to M11). Within the hydrophobic clusters, rat NCKX2 shares 80% identity and 91% similarity with bovine NCKX1. The two larger hydrophilic loops are much shorter in NCKX2 than in NCKX1, accounting largely for the difference in length between the two proteins, and are dissimilar in sequence except for a 32-amino acid stretch with 69% identity in the cytosolic loop. NCKX2 was epitope-tagged in the extracellular domain and was shown to be expressed at the surface of transfected HEK cells. Analysis of NCKX2 function by fluorescent imaging of fura-2-loaded transfected cells demonstrated that NCKX2 is a potassium-dependent sodium/calcium exchanger.

Alternative promoters and cardiac muscle cell-specific expression of the Na+/Ca2+ exchanger gene

Many studies have investigated the regulation of the Na+/ Ca2+ exchanger, NCX1, but limited data exist on transcriptional regulation of the NCX1 gene. We have identified the transcription start sites of three tissue-specific alternative promoters of NCX1 transcripts from rat heart, kidney, and brain. We have characterized the cardiac NCX1 promoter, from which the most abundant quantities of NCX1 transcripts are expressed. Transfection of primary cardiac myocytes, CHO cells, and COS-7 cells with overlapping genomic DNA fragments spanning the NCX1 cardiac transcription start site has uncovered a cardiac cell-specific minimum promoter from -137 to +85. The cardiac NCX1 promoter is TATA-less but has putative binding sites for cardiac-specific GATA factors, an E box, and an Inr as well as multiple active enhancers. The kidney NCX1 promoter has a typical TATA box and binding sites for several tissue-specific factors. The brain NCX1 promoter is very GC-rich and possesses several Sp-1 binding sites consistent with its ubiquitous expression.

A new diagnostic approach to biliary atresia with emphasis on the ultrasonographic triangular cord sign: comparison of ultrasonography, hepatobiliary scintigraphy, and liver needle biopsy in the evaluation of infantile cholestasis

BACKGROUND/PURPOSE

The authors evaluated prospectively the utility of ultrasonography, Tc-99m-DISIDA hepatobiliary scintigraphy, and liver needle biopsy in differentiating biliary atresia (BA) from intrahepatic cholestasis in 73 consecutive infants who had cholestasis.

METHODS

Sixty three ultrasonographic examinations of 61 infants with 7.0-MHz transducer were carried out, focusing on the fibrous tissue at the porta hepatis. The authors defined the triangular cord (TC) as visualization of a triangular or tubular shaped echogenic density just cranial to the portal vein bifurcation on a transverse or longitudinal scan.

RESULTS

Although 17 of 20 ultrasonographic examinations from infants who had BA denoted TC, 43 ultrasonographic examinations from infants with either neonatal hepatitis (NH) or other causes of cholestasis denoted no TC, showing a diagnostic accuracy of 95% with 85% sensitivity and 100% specificity. Investigation with Tc-99m-DISIDA hepatobiliary scintigraphy showed that 24 of 25 infants who had BA had no gut excretion, and 16 of 46 infants who had either NH or other causes of cholestasis had gut excretion, showing a diagnostic accuracy of 56% with 96% sensitivity and 35% specificity. Therefore, gut excretion of tracer excluded BA, but no gut excretion of tracer needed further investigations as liver needle biopsy. Forty-four liver needle biopsies were carried out in 19 infants who had BA and 24 infants who had either NH or other causes of cholestasis. Although 18 of 20 biopsy findings in infants who had BA were correctly interpreted as having BA, 23 of 24 biopsy results in infants who had either NH or other causes of cholestasis were correctly diagnosed, showing a diagnostic accuracy of 93% with 90% sensitivity and 96% specificity.

CONCLUSIONS

Since the introduction of ultrasonographic TC sign in the diagnosis of BA by our institution, we have found that it seemed to be a simple, time-saving, highly reliable, and non-invasive tool in the diagnosis of BA from other causes of cholestasis. The authors propose a new diagnostic strategy in the evaluation of infantile cholestasis with emphasis on ultrasonographic TC sign as first priority of investigations. When the TC is visualized, prompt exploratory laparotomy is mandatory without further investigations. When the TC is not visualized, hepatobiliary scintigraphy is the next step. Excretion of tracer into the small bowel actually rules out BA. Liver needle biopsy is reserved only for the infants with no excretion of tracer. The authors believe that a correct decision regarding the need for surgery can be made in almost all cases with infantile cholestasis by this multidisciplinary approach.

New inhibitors of thrombin and other trypsin-like proteases: hydrogen bonding of an aromatic cyano group with a backbone amide of the P1 binding site replaces binding of a basic side chain

Highly effective thrombin inhibitors have been obtained by preparing boronic acid analogues of m-cyano-substituted phenylalanine and its incorporation into peptides. The cyano group enhances binding by several orders of magnitude. For example, Ac-(D)Phe-Pro-boroPheOH binds to thrombin with a Ki of 320 nM and the Ki of Ac-(D)Phe-Pro-boroPhe(m-CN)-OH is 0.79 nM. Protein crystal structure determination of trypsin complexed to H-(D)Phe-Pro-boroPhe(m-CN)-OH indicates that the aromatic side chain is bound in the P1 binding site and that the cyano group can act as a H-bond acceptor for the amide proton of Gly219. Enhanced binding for inhibitors containing the m-cyano group was observed for coagulation factor Xa and for the factor VIIa.tissue factor complex [Ki values of Ac-(D)Phe-Pro-boroPhe(mCN)-OH are 760 and 3.3 nM, respectively]. This result is consistent with the sequence homology of these two enzymes in the P1 binding site. Two enzymes lacking the strict homology in the P1 binding site, pancreatic kallikrein and chymotrypsin, did not exhibit significantly enhanced binding.

Inhibitory effect of heparin on serotonin-induced hyperplasia and hypertrophy of smooth muscle cells

Serotonin (5-HT) produces both hyperplastic and hypertrophic effects on smooth muscle cell (SMC) in culture. Heparin is known to inhibit serum-induced hyperplasia of SMC but has not been previously tested on the stimulatory effect of 5-HT on SMC. Our present data show that at 24 h heparin inhibited by 50% the stimulation of 3H-thymidine incorporation into bovine pulmonary artery SMC and at 7 days totally reversed both cellular proliferation and enlargement of SMC produced by 1 microM 5-HT. Heparin failed to alter 5-HT uptake by SMC, but inhibited the stimulation of tyrosine phosphorylation of GTPase-activating protein, a proposed intermediate in the 5-HT stimulatory process. Thus heparin inhibits both hyperplastic and hypertrophic effects of 5-HT on SMC, perhaps through the inhibition of a phosphorylated intermediate protein.

A new role for an old molecule: serotonin as a mitogen

Serotonin (5-hydroxytryptamine) has been known for the last half century to influence vasoactivity and to participate in neurotransmission. More recently, this compound has been recognized to cause proliferation of a variety of cells in culture, including those of vascular smooth muscle. Furthermore, the proliferative effect is synergistic with that of more conventional growth-producing polypeptides. A hypertrophic, as well as a proliferative response, has been shown to occur in some smooth muscle cells. Whether the mitogenic effect is initiated through a cell surface receptor or a serotonin transporter, or both depending on the cell type, is currently unresolved. Most evidence indicates that cellular cyclic nucleotides play an important role in the intracellular signaling process for growth regulation by serotonin, and newer studies point to protein phosphorylation pathways as being important in the mitogenic response. It has been proposed that, through these signaling pathways, serotonin plays an important role in remodeling of both the pulmonary and systemic circulations.

Association of Tyr phosphorylation of GTPase-activating protein with mitogenic action of serotonin

We have previously shown that serotonin (5-HT) induces both hyperplasia and hypertrophy of pulmonary artery smooth muscle cells (SMC) but not of endothelial cells (EC) through its high-affinity uptake. The present studies demonstrate rapid enhancement by 5-HT of Tyr phosphorylation of proteins, including p120, which also occurs in SMC but not in EC. The p120 protein was identified as GTPase-activating protein (GAP) by immunoprecipitation. Its phosphorylation occurred within minutes and preceded other events associated with 5-HT-induced mitogenesis. Tyr kinase (TK) and 5-HT uptake inhibitors and 8-bromoadenosine 3',5'-cyclic monophosphate blocked both the 5-HT-induced DNA synthesis and Tyr phosphorylation of GAP. Vanadate elevated DNA synthesis and Tyr phosphorylation of GAP of both control and 5-HT-treated cells. 5-HT failed to alter Tyr phosphorylation of GAP in cellular homogenates, as opposed to intact cells. In the presence of 3-isobutyl-1-methylxanthine, 5-HT inhibited cellular growth, presumably through its action on 5-HT1A or 5-HT4 receptors and elevation of adenosine 3',5'-cyclic monophosphate, but this was not associated with an alteration of Tyr phosphorylation of GAP. Similarly, a 5-HT1 or 5-HT2 receptor agonist failed to stimulate Tyr phosphorylation or DNA synthesis of SMC. Stimulation of cellular proliferation and enlargement produced by 1 microM 5-HT were totally abolished by TK inhibitors that did not affect 5-HT uptake. These data indicate that Tyr phosphorylation of GAP may act as an intermediate signal in 5-HT-induced mitogenesis of SMC which requires cellular internalization of 5-HT rather than its action on a membrane receptor.

Does increased spending on alcoholism treatment lead to lower cirrhosis death rates?

The purpose of this study was to see if recent changes in the funding of alcoholism programmes in the United States were related to changes in liver cirrhosis death rates. Data on per-capita spending, per-capita alcohol consumption and cirrhosis death rates were gathered from various sources for the years 1979 and 1989 for the 50 states and the District of Columbia. Regression analysis showed that greater increases in spending on alcoholism across US states were associated with greater declines in cirrhosis mortality rates. Since alcohol-related deaths cause large productivity losses and treatment is relatively cheap this creates large savings for society.

Luteinizing hormone deficiency and female infertility in mice lacking the transcription factor NGFI-A (Egr-1)

The immediate-early transcription factor NGFI-A (also called Egr-1, zif/268, or Krox-24) is thought to couple extracellular signals to changes in gene expression. Although activins and inhibins regulate follicle-stimulating hormone (FSH) synthesis, no factor has been identified that exclusively regulates luteinizing hormone (LH) synthesis. An analysis of NGFI-A-deficient mice derived from embryonic stem cells demonstrated female infertility that was secondary to LH-beta deficiency. Ovariectomy led to increased amounts of FSH-beta but not LH-beta messenger RNA, which suggested a pituitary defect. A conserved, canonical NGFI-A site in the LH-beta promoter was required for synergistic activation by NGFI-A and steroidogenic factor-1 (SF-1). NGFI-A apparently influences female reproductive capacity through its regulation of LH-beta transcription.

Unimpaired macrophage differentiation and activation in mice lacking the zinc finger transplantation factor NGFI-A (EGR1)

The zinc finger protein NGFI-A (also called EGR1, Krox24, or zif268) is a candidate regulator of myeloid cell differentiation. Evidence supporting this hypothesis is twofold. First, NGFI-A antisense oligonucleotides prevent macrophage differentiation in HL-60 and U937 myeloid leukemia cell lines and in normal bone marrow cells. Second, enforced expression of NGFI-A blocks granulocytic differentiation and promotes macrophage differentiation in HL-60 cells and in the hematopoietic progenitor cell line 32D. We sought to determine the effect of NGFI-A deficiency on macrophage differentiation and function in vivo by examining native bone marrow cells from mice homozygous for a disrupted allele of NGFI-A derived from gene-targeted ES cells. Macrophages were observed in peripheral blood and several tissues, indicating that NGFI-A was not required for the formation of a variety of macrophage compartments. No differences in myeloid cell differentiation were observed between wild-type and NGFI-A-/- bone marrow cells cultured in the presence of macrophage, granulocyte-macrophage, or granulocyte colony-stimulating factor (M-CSF, GM-CSF, or G-CSF). Activation of NGFI-A-/- macrophages was comparable to that of wild-type macrophages as determined by nitric oxide production and increased cell surface expression of class II major histocompatibility complex molecules. Moreover, NGFI-A-/- mice showed no increased mortality or bacteria] burden when challenged with Listeria monocytogenes. Together, these results indicate that NGFI-A is not required for macrophage differentiation or activation.

5-Oxo-eicosanoids and hematopoietic cytokines cooperate in stimulating neutrophil function and the mitogen-activated protein kinase pathway

The newly defined eicosatetraenoates (ETEs), 5-oxoETE and 5-oxo-15(OH)-ETE, share structural motifs, synthetic origins, and bioactions with leukotriene B4 (LTB4). All three eicosanoids stimulate Ca2+ transients and chemotaxis in human neutrophils (PMN). However, unlike LTB4, 5-oxoETE and 5-oxo-15(OH)-ETE alone cause little degranulation and no superoxide anion production. However, we show herein that, in PMN pretreated with granulocyte-macrophage or granulocyte colony-stimulating factor (GM-CSF or G-CSF), the oxoETEs become potent activators of the last responses. The oxoETEs also induce translocation of secretory vesicles from the cytosol to the plasmalemma, an effect not requiring cytokine priming. To study the mechanism of PMN activation in response to the eicosanoids, we examined the activation of mitogen-activated protein kinase (MAPK) and cytosolic phospholipase A2 (cPLA2). PMN expressed three proteins (40, 42, and 44 kDa) that reacted with anti-MAPK antibodies. The oxoETEs, LTB4, GM-CSF, and G-CSF all stimulated PMN to activate the MAPKs and cPLA2, as defined by shifts in these proteins' electrophoretic mobility and tyrosine phosphorylation of the MAPKs. However, the speed and duration of the MAPK response varied markedly depending on the stimulus. 5-OxoETE caused a very rapid and transient activation of MAPK. In contrast, the response to the cytokines was rather slow and persistent. PMN pretreated with GM-CSF demonstrated a dramatic increase in the extent of MAPK tyrosine phosphorylation and electrophoretic mobility shift in response to 5-oxoETE. Similarly, 5-oxoETE induced PMN to release some preincorporated [14C]arachidonic acid, while GM-CSF greatly enhanced the extent of this release. Thus, the synergism exhibited by these agents is prominent at the level of MAPK stimulation and phospholipid deacylation. Pertussis toxin, but not Ca2+ depletion, inhibited MAPK responses to 5-oxoETE and LTB4, indicating that responses to both agents are coupled through G proteins but not dependent upon Ca2+ transients. 15-OxoETE and 15(OH)-ETE were inactive while 5-oxo-15(OH)-ETE and 5(OH)-ETE had 3- and 10-fold less potency than 5-oxoETE, indicating a rather strict structural specificity for the 5-keto group. LY 255283, a LTB4 antagonist, blocked the responses to LTB4 but not to 5-oxoETE. Therefore, the oxoETEs do not appear to operate through the LTB4 receptor. In summary, the oxoETEs are potent activators of PMN that share some but not all activities with LTB4. The response to the oxoETEs is greatly enhanced by pretreatment with cytokines, indicating that combinations of these mediators may be very important in the pathogenesis of inflammation.

Pathways for degradation of the catalytic subunit of cAMP-dependent protein kinase differ in wild-type and kinase-negative S49 mouse lymphoma cells

The catalytic subunit of cAMP-dependent protein kinase radiolabeled with [35S]methionine in wild-type S49 mouse lymphoma cells was degraded with half-lives of approximately 9.2 h in unstimulated cells and approximately 4.5 h in cells stimulated with a membrane-permeable cAMP analog. Turnover in kinase-negative mutant cells was about three times faster than in stimulated wild-type cells and appeared to involve a unique 47-kDa intermediate. Levels of catalytic subunit protein revealed by Western immunoblotting were consistent with the measured differences in turnover, but whereas the protein was mostly soluble in wild-type cell extracts, it was almost entirely insoluble in the mutant cell extracts. A substantial fraction of the catalytic subunit labeled in a 5-min pulse was soluble in kinase-negative cell extracts, but most of this material was rendered insoluble by incubating the cells for an additional 30 min before extraction. Degradation of the catalytic subunit in kinase-negative, but not in wild-type, cells was inhibited strongly by two specific peptide aldehyde inhibitors of the proteasomal chymotrypsin-like activity. An inhibitor of the proteasomal protease that prefers branched-chain amino acids had less of an effect on catalytic subunit degradation in the mutant cells.

5-Oxo-eicosatetraenoate is a broadly active, eosinophil-selective stimulus for human granulocytes

5-Oxo-eicosatetraenoate (5-oxoETE) is gaining recognition as a chemotactic factor for eosinophilic (Eo) as well as neutrophilic (Neu) polymorphonuclear leukocytes. We found that the eicosanoid was far stronger than C5a, platelet-activating factor (PAF), leukotriene B4 (LTB4), or FMLP in stimulating Eo chemotaxis. Moreover, it had weak intrinsic degranulating effects on otherwise unstimulated Eo, produced prominent degranulation responses in Eo primed by granulocyte-macrophage CSF, and enhanced the Eo-degranulating potencies of PAF, C5a, LTB4, and FMLP by up to 10,000-fold. Low picomolar levels of 5-oxoETE also induced Eo to activate mitogen-activated protein kinases (MAPKs), as defined by shifts in the electrophoretic mobility and tyrosine phosphorylation of two immunodetectable proteins, p44 and p42. 5-OxoETE was > or = 100-fold weaker or unable to stimulate any of these responses in Neu. Finally, 5-oxo-15-hydroxy-ETE and 5-hydroxy-ETE activated both cell types, but were weaker than 5-oxoETE and had Eo/Neu potency ratios approaching unity. 5-OxoETE, thus, is uniquely potent and selective in promoting Eo not only to migrate, but also to release granule enzymes and activate MAPKs. By triggering MAPK activation, the eicosanoid may also influence the production of anaphylactoid lipids (e.g., PAF), arachidonic acid metabolites, and cytokines. 5-OxoETE therefore possesses a biologic profile well suited for mediating Eo-dominated allergic reactions in vivo.

5-Oxo-eicosatetraenoate is a broadly active, eosinophil-selective stimulus for human granulocytes

5-Oxo-eicosatetraenoate (5-oxoETE) is gaining recognition as a chemotactic factor for eosinophilic (Eo) as well as neutrophilic (Neu) polymorphonuclear leukocytes. We found that the eicosanoid was far stronger than C5a, platelet-activating factor (PAF), leukotriene B4 (LTB4), or FMLP in stimulating Eo chemotaxis. Moreover, it had weak intrinsic degranulating effects on otherwise unstimulated Eo, produced prominent degranulation responses in Eo primed by granulocyte-macrophage CSF, and enhanced the Eo-degranulating potencies of PAF, C5a, LTB4, and FMLP by up to 10,000-fold. Low picomolar levels of 5-oxoETE also induced Eo to activate mitogen-activated protein kinases (MAPKs), as defined by shifts in the electrophoretic mobility and tyrosine phosphorylation of two immunodetectable proteins, p44 and p42. 5-OxoETE was &gt; or = 100-fold weaker or unable to stimulate any of these responses in Neu. Finally, 5-oxo-15-hydroxy-ETE and 5-hydroxy-ETE activated both cell types, but were weaker than 5-oxoETE and had Eo/Neu potency ratios approaching unity. 5-OxoETE, thus, is uniquely potent and selective in promoting Eo not only to migrate, but also to release granule enzymes and activate MAPKs. By triggering MAPK activation, the eicosanoid may also influence the production of anaphylactoid lipids (e.g., PAF), arachidonic acid metabolites, and cytokines. 5-OxoETE therefore possesses a biologic profile well suited for mediating Eo-dominated allergic reactions in vivo.

Nitroprusside inhibits serotonin-induced mitogenesis and tyrosine phosphorylation of smooth muscle cells

Serotonin (5-hydroxytryptamine, 5-HT) produces hyperplasia and hypertrophy of bovine pulmonary artery smooth muscle cells (SMC) in culture. The growth responses are associated with early elevations of c-myc and actin gene expressions and are blocked by agents that elevate cellular adenosine 3',5'-cyclic monophosphate or inhibit 5-HT transport or tyrosine phosphorylation. A rapid enhancement of tyrosine phosphorylation of a 120-kDa protein (p120) is associated with the 5-HT-induced mitogenesis. In the present studies, sodium nitroprusside (SNP, 10-100 micromol/l), a NO-generating agent, dose dependently inhibited 5-HT-induced thymidine incorporation by SMC. Inhibition of the 5-HT stimulatory effect was also observed with isosorbide dinitrate and nitroglutathione, which are also NO donors. Incubation of cells with 8-bromoguanosine 3',5'-cyclic monophosphate (1 micromol/l) mimicked the antimitogenic action of SNP. The antiproliferative effect of SNP was inhibited by hemoglobin (50 micromol/l) and potentiated by superoxide dismutase (200 U/ml), supporting the role of NO in the process. Enhancement of tyrosine phosphorylation of p120 by 5-HT was prevented by preincubation with SNP or exogenously added guanosine 3',5'-cyclic monophosphate. The data indicate that 5-HT acts as a mitogen for SMC through a signal transduction pathway involving tyrosine phosphorylation. SNP likely prevents the 5-HT-induced mitogenesis of SMC through elevation of intracellular guanosine 3',5'-cyclic monophosphate and inhibition of tyrosine phosphorylation of p120.

Methods for studying synthesis, turnover, and phosphorylation of catalytic subunit of cAMP-dependent protein kinase in mammalian cells

Because of the low abundance of the two major isoforms (C alpha and C beta) of catalytic (C) subunit of cAMP-dependent protein kinase, it has been difficult to monitor their expression and virtually impossible to quantify their synthesis, phosphorylation, and turnover in intact mammalian cells. We now describe sensitive and quantitative immunochemical methods using a goat antibody raised against the recombinant C alpha isoform of murine C subunit that enable studies of the expression and metabolism of C subunit in cultured cells. The antibody reacts well with C alpha and C beta isoforms of murine C subunit and with C subunits from rat, hamster, and human cell lines, so it should have widespread utility. Immunoreactivity with bovine heart C subunit was substantially weaker. For quantitation of C subunit radioactivity in extracts of cells labeled metabolically with [35S]methionine, we developed a two-cycle immunoadsorption protocol that reduces nonspecific adsorption to negligible levels. A tritium-labeled, truncated C subunit marker protein is added to extracts as an internal marker to monitor C subunit recoveries in different samples. For analysis of expression of C subunit isoforms in different cells or tissues, we describe a nonradioactive Western immunoblot procedure that can quantitate C subunit in amounts as low as 12 pg. Using extraction conditions that either stabilize or destabilize the phosphate on Thr-197, we show how the relative expression and phosphorylation of C alpha and C beta isoforms can be estimated from SDS-gel patterns resulting from either immunoblot or immunoadsorption procedures.

Dehydration natriuresis in male rats is mediated by oxytocin

In a previous study in rats we demonstrated the existence of osmoregulatory natriuretic mechanisms distinct from the natriuretic mechanisms that are dependent on volume stimulation. At the same time, we found that oxytocin (OT) receptors were important mediators of natriuresis induced by hypernatremia but not of that induced by isotonic volume expansion. In the present study, the role of OT in dehydration natriuresis was examined in conscious rats. Dehydration for 24 h caused hypernatremia (from 142.1 +/- 0.4 to 147.7 +/- 0.7 mmol/l) and natriuresis accompanied by an approximately 30% spontaneous reduction of food intake. In conjunction with renal retention of water caused by an increase in circulating vasopressin, the natriuresis and probably the reduction of food intake can help to counteract the rise in body fluid osmolality. This natriuresis could not be fully explained by the reduction in plasma aldosterone. Plasma OT concentration had increased from 15.5 +/- 1.2 to 23.8 +/- 2.0 pg/ml at the end of 24 h of dehydration. Intravenous infusion of a selective OT-receptor antagonist [Mpa1,D-Tyr(Et)2, Thr4, Orn8]-OT using osmotic minipumps prevented dehydration natriuresis. It is concluded that in a dehydration-induced hypernatremic state OT is released, inducing natriuresis and facilitating sodium homeostasis. This mechanism is activated by Na osmoreceptors, but is not primarily dependent on the volume status.

31P nuclear magnetic resonance spectroscopic evidence that canine nucleus pulposus and anulus fibrosus cells differ in principal organophosphorus biomolecules

STUDY DESIGN

31P Nuclear magnetic resonance spectroscopy was used to compare amounts and types of principal organophosphorus biomolecules in canine intervertebral disc tissues ex vivo.

OBJECTIVE

The goal of this study was to compare principal organophosphorus biomolecules in nucleus pulposus, anulus fibrosus, and in isolated nucleus pulposus and anulus fibrosus cells.

SUMMARY OF BACKGROUND DATA

There is no published information on principal organophosphorus biomolecules in disc tissues for any animal.

METHODS

Canine nucleus pulposus and anulus fibrosus were shown by hematoxylin-eosin staining to be healthy tissues characteristic of adult dogs. Viable cells liberated from these disc tissues by sequential protease digestion were directly visualized by light microscopy of wet mounts. 31P nuclear magnetic resonance spectra were recorded at room temperature for 12 hours according to conventional published methods.

RESULTS

No resonances were detected for intact nucleus pulposus and anulus fibrosus tissue. 31P nuclear magnetic resonance spectra of viable chondrocyte-like cells from anulus fibrosus featured two distinctive resonance peaks consistent with phosphomonoesters and phosphodiesters. After undigested anulus fibrosus was removed, no resonances were detected. 31P nuclear magnetic resonance spectra of viable chondrocyte-like cells from nucleus pulposus before and after removal of undigested tissue featured only one resonance peak consistent with phosphodiesters.

CONCLUSIONS

A phosphomonoester-containing biomolecule is present in healthy canine anulus fibrosus tissue but not in nucleus pulposus tissue, nor in nucleus pulposus cells or anulus fibrosus cells. A phosphodiester-containing biomolecule is present principally in nucleus pulposus cells. This study demonstrated that canine chondrocyte-like cells from nucleus pulposus and anulus fibrosus are phenotypically distinctive in principal organophosphorus biomolecules.