Solution (1)H NMR study of the influence of distal hydrogen bonding and N terminus acetylation on the active site electronic and molecular structure of Aplysia limacina cyanomet myoglobin

The sea hare Aplysia limacina possesses a myoglobin in which a distal H-bond is provided by Arg E10 rather than the common His E7. Solution (1)H NMR studies of the cyanomet complexes of true wild-type (WT), recombinant wild-type (rWT), and the V(E7)H/R(E10)T and V(E7)H mutants of Aplysia Mb designed to mimic the mammalian Mb heme pocket reveal that the distal His in the mutants is rotated out of the heme pocket and is unable to provide a stabilizing H-bond to bound ligand and that WT and rWT differ both in the thermodynamics of heme orientational disorder and in heme contact shift pattern. The mean of the four heme methyl shifts is shown to serve as a sensitive indicator of variations in distal H-bonding among a set of mutant cyanomet globins. The heme pocket perturbations in rWT relative to WT were traced to the absence of the N-terminal acetyl group in rWT that participates in an H-bond to the EF corner in WT. Analysis of dipolar contacts between heme and axial His and between heme and the protein matrix reveal a small approximately 2 degrees rotation of the axial His in rWT relative to true WT and a approximately 3 degrees rotation of the heme in the double mutant relative to rWT Mb. It is demonstrated that both the direction and magnitude of the rotation of the axial His relative to the heme can be determined from the change in the pattern of the contact-dominated heme methyl shift and from the dipolar-dominated heme meso-H shift. However, only NOE data can determine whether it is the His or heme that actually rotates in the protein matrix.

Signaling pathways mediating anti-apoptotic action of neurotrophins

Neurotrophins promote survival and suppress apoptosis in many populations of neurons. Currently, phosphatidylinositol-3 kinase (PI-3K) is recognized as the main mediator of this protective effect. However, most of the data collected so far on the anti-apoptotic signaling of neurotrophins were obtained using trophic withdrawal paradigms. Recent data from our and other groups indicate that extracellular-signal-regulated kinase 1/2 (Erk 1/2) may play a critical role in suppressing neuronal apoptosis triggered by cellular damage. Thus, it appears that either Erk1/2 or PI-3K, depending on the nature of the death-inducing stimulus, can mediate anti-apoptotic signaling of neurotrophins. In this review, we discuss the contribution of Erk1/2 and PI-3K to neuroprotection by neurotrophins. We also present data suggesting possible mechanisms by which these pathways might suppress neuronal death.

1H NMR investigation of the distal hydrogen bonding network and ligand tilt in the cyanomet complex of oxygen-avid Ascaris suum hemoglobin

The O(2)-avid hemoglobin from the parasitic nematode Ascaris suum exhibits one of the slowest known O(2) off rates. Solution (1)H NMR has been used to investigate the electronic and molecular structural properties of the active site for the cyano-met derivative of the recombinant first domain of this protein. Assignment of the heme, axial His, and majority of the residues in contact with the heme reveals a molecular structure that is the same as reported in the A. suum HbO(2) crystal structure (Yang, J., Kloek, A., Goldberg, D. E., and Mathews, F. S. (1995) Proc. Natl. Acad. Sci. U. S. A. 92, 4224-4228) with the exception that the heme in solution is rotated by 180 degrees about the alpha,gamma-meso axis relative to that in the crystal. The observed dipolar shifts, together with the crystal coordinates of HbO(2), provide the orientation of the magnetic axes in the molecular framework. The major magnetic axis, which correlates with the Fe-CN vector, is found oriented approximately 30 degrees away from the heme normal and indicates significant steric tilt because of interaction with Tyr(30)(B10). The three side chain labile protons for the distal residues Tyr(30)(B10) and Gln(64)(E7) were identified, and their relaxation, dipolar shifts, and nuclear Overhauser effects to adjacent residues used to place them in the distal pocket. It is shown that these two distal residues exhibit the same orientations ideal for H bonding to the ligand and to each other, as found in the A. suum HbO(2) crystal. It is concluded that the ligated cyanide participates in the same distal H bonding network as ligated O(2). The combination of the strong steric tilt of the bound cyanide and slow ring reorientation of the Tyr(30)(B10) side chain supports a crowded and constrained distal pocket.

The antidepressants imipramine, clomipramine, and citalopram induce apoptosis in human acute myeloid leukemia HL-60 cells via caspase-3 activation

Some widely used antidepressants such as imipramine, clomipramine, and citalopram have been found to possess antineoplastic effects. In the present study, these compounds were found to induce apoptotic cell death in human acute myeloid leukemia HL-60 cells. Apoptosis induced by the antidepressants was identified by electron microscopy and conventional agarose gel electrophoresis and was quantitated by propodium iodide staining and the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) via flow cytometry. Treatment with apoptosis-inducing concentrations of the antidepressants (80 microM imipramine, 35 microM clomipramine, or 220 microM citalopram) caused induction of caspase-3/caspase-3-like activity, which was monitored by the cleavage of poly(ADP-ribose) polymerase (PARP), the loss of the 32 kD caspase-3 (CPP32) precursor, and the cleavage of the fluorescent CPP32-like substrate PhiPhiLux. Pretreatment with a potent caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl-ketone (zVAD-fmk) inhibited antidepressant-induced CPP32/CPP32-like activity and apoptosis. Furthermore, activation of caspase induced by the antidepressants was preceded by the hypergeneration of intracellular reactive oxygen species (ROS). These results suggested that the antidepressants may induce apoptosis via a caspase-3-dependent pathway, and induction of apoptosis by the antidepressants may provide a clue for the mechanism of their antineoplastic effects.

Neuroprotection by brain-derived neurotrophic factor is mediated by extracellular signal-regulated kinase and phosphatidylinositol 3-kinase

Apoptosis is a form of programmed cell death that plays a pivotal role during development and in the homeostasis of the adult nervous systems. However, mechanisms that regulate neuronal apoptosis are not well defined. Here, we report that brain-derived neurotrophic factor (BDNF) protects cortical neurons against apoptosis induced by camptothecin or serum deprivation and activates the extracellular-signal-regulated kinase (ERK) and the phosphatidylinositol 3-kinase (PI 3-kinase) pathways. Using pharmacological agents and transient transfection with dominant interfering or constitutive active components of the ERK or the PI 3-kinase pathway, we demonstrate that the ERK pathway plays a major role in BDNF neuroprotection against camptothecin. Furthermore, ERK is activated in cortical neurons during camptothecin-induced apoptosis, and inhibition of ERK increases apoptosis. In contrast, the PI 3-kinase pathway is the dominant survival mechanism for serum-dependent survival under normal culture conditions and for BDNF protection against serum withdrawal. These results suggest that the ERK pathway is one of several neuroprotective mechanisms that are activated by stress to counteract death signals in central nervous system neurons. Furthermore, the relative contribution of the ERK and PI 3-kinase pathways to neuronal survival may depend on the type of cellular injury.

Pregnancy after tubal sterilization with bipolar electrocoagulation. U.S. Collaborative Review of Sterilization Working Group

OBJECTIVE

To determine risk factors for pregnancy after tubal sterilization with bipolar electrocoagulation.

METHODS

A total of 2267 women who had bipolar electrocoagulation were followed for up to 8 to 14 years as part of a multicenter, prospective, cohort study conducted in medical centers in nine United States cities. We used proportional hazards analysis and cumulative life-table probabilities to assess pregnancy risk in these women.

RESULTS

The 5-year cumulative probability of pregnancy for women sterilized in 1978-1982 was 19.5 per 1000 procedures (95% confidence interval [CI], 12.2, 26.9); the comparable probability for women sterilized in 1985-1987 was significantly lower, 6.3 per 1000 procedures (95% CI, 0.0, 13.5) (one-tailed P = .01). Women enrolled in 1985-1987 who had fewer than three sites of coagulation had a probability of failure of 12.9 per 1000 procedures (95% CI, 0.0, 38.0); by contrast, women who had three or more sites coagulated had a probability of failure of 3.2 per 1000 procedures (95% CI, 0.0, 9.6) (one-tailed P = .01).

CONCLUSION

The long-term probability of pregnancy after tubal sterilization with bipolar coagulation was very low when three or more sites of the fallopian tube were coagulated. Bipolar coagulating systems can be highly effective for sterilization when the fallopian tube is coagulated adequately.

Synthesis and biological evaluation of butanoate, retinoate, and bis(2,2,2-trichloroethyl)phosphate derivatives of 5-fluoro-2'-deoxyuridine and 2',5-difluoro-2'-deoxyuridine as potential dual action anticancer prodrugs

A group of 3'-O-butanoyl, 5'-O-butanoyl, and 3',5'-di-O-butanoyl esters of 5-fluoro-2'-deoxyuridine (FDU), and 2',5-difluoro-2'-deoxyuridine (DFDU), 3'-O-retinoyl, and 3',5'-di-O-retinoyl esters of FDU, and 5'-O-bis(2,2,2-trichloroethyl)phosphoryl-FDU and its 3'-O-butanoyl ester, was synthesized. These compounds were designed to act as double prodrugs that would serve as a depot to release two active drugs that act through different mechanisms. Thus, a nucleotide derivative of FDU or DFDU could act as a competitive inhibitor for thymidylate synthase, whereas retinoic acid and butyric acid would be expected to induce cell differentiation. The in vitro anticancer activities for these prodrugs were determined against a panel of nine tumor types (leukemia, non-small cell lung, colon, CNS, melanoma, ovarian, renal, prostate, breast) that encompassed about 60 human tumor cell lines. Structure-activity relationships indicate that O-butanoyl esters of FDU are approximately equipotent to FDU, the O-butanoyl esters of DFDU are less active than FDU, and the retinoyl and bis(2,2,2-trichloroethyl)phosphate derivatives of FDU exhibit comparable activity to FDU. In addition to their cytotoxic effect, 3'-O-retinoyl-FDU (12) and 3'-O-butanoyl-5'-O-bis(2,2,2-trichloroethyl)phosphoryl-FD U (16) also induced in vitro cell differentiation of promyelocytic leukemia HL60 cells. These combined cytotoxic and cell differentiation effects exhibited by 12 and 16 produced greater morphological drug-induced granulation and neutrophil vacuolation, and more cell apoptosis, than observed upon exposure to either retinoic acid or sodium butanoate. Dose-escalation studies in mice showed that 12 or 16 did not induce any acute or chronic toxicity, change in plasma clinical chemistry parameters, or gross histapathological changes at 60 days following an initial dosage regimen of 0.013 mmol/kg i.p. for 7-consecutive days. The in vivo growth delay response of murine mammary EMT6 solid tumors suggests that 3'-O-retinoyl-FDU (12) delays tumor growth relative to the other prodrugs investigated, sodium butyrate, retinoic acid, FDU, or a combination of retinoic acid and FDU. These preliminary results suggest that 3'-O-retinoyl-FDU (12) warrants further in vivo investigation to determine its tissue biodistribution and pharmacokinetic parameters that would be of value in assessing its potential usefulness as an anticancer prodrug.

Trends in prostatectomy for benign prostatic hyperplasia among black and white men in the United States: 1980 to 1994

OBJECTIVES

To estimate the annual rate of discharge for prostatectomy for benign prostatic hyperplasia (BPH) in black and white men from 1980 to 1994 using the National Hospital Discharge Survey.

METHODS

Overall and race-, age-, and year-specific utilization rates were estimated for the civilian population in the United States. Length of stay was calculated for each discharge, and the results were plotted over time. An expected number of discharges based on the rates observed in 1980 was estimated to determine the impact of decreased prostatectomy rates on the number of procedures that would have been expected in this aging population.

RESULTS

Discharge rates for whites were within a narrow range (233.2 to 274.5 per 100,000) from 1980 through 1990 and then displayed a monotonic decline after 1991 to 131.3 per 100,000 in 1994. Rates for blacks were 10% to 24% lower from 1980 to 1991; the decline in discharge rates began in 1993 for blacks, and by 1994 the racial gap had closed. Length of stay decreased throughout the period but length of stay averaged 30% longer for blacks throughout. On the basis of the observed rates of 1980, there were more than 140,000 fewer prostatectomies performed for BPH in 1994 than would have been expected owing to the aging of the population.

CONCLUSIONS

These data demonstrate that the black/white differences in prostatectomy for BPH that were observed in the 1980s have disappeared in recent years. Furthermore, rates have declined dramatically in all age- and race-specific groups. Further work is needed to determine whether this convergence in discharge rates is due to equalization of access to medical care or to differences in utilization of alternative therapies.

Changes in the generation of reactive oxygen species and in mitochondrial membrane potential during apoptosis induced by the antidepressants imipramine, clomipramine, and citalopram and the effects on these changes by Bcl-2 and Bcl-X(L)

In order to investigate the molecular mechanism of the antineoplastic effects exerted by the antidepressive agents imipramine, clomipramine, and citalopram, we examined the effects of these compounds on cell viability, generation of reactive oxygen species (ROS), and mitochondrial membrane potential (DeltaPsi(m)) in human acute myeloid leukemia HL-60 cells. Our results indicate that exposure to these compounds causes a loss in cell viability by activating the apoptotic process, as identified by electron microscopy, DNA gel electrophoresis, and flow cytometry. The increased generation of ROS induced by these drugs was a relatively early event and preceded the loss of DeltaPsi(m). Overexpression of the antiapoptotic protein Bcl-2 or Bcl-X(L) prevents antidepressant-induced apoptosis, as well as loss of DeltaPsi(m), but does not affect the generation of ROS.

Granzyme A loading induces rapid cytolysis and a novel form of DNA damage independently of caspase activation

Cytotoxic lymphocytes trigger apoptosis by releasing perforin and granzymes (Grn). GrnB activates the caspase apoptotic pathway, but little is known about GrnA-induced cell death. Perforin was used to load recombinant GrnA and GrnB and enzymatically inactive variants into target cells. GrnA induces single-strand DNA breaks that can be labeled with Klenow polymerase and visualized on alkaline gels. GrnA-induced DNA damage but not cytolysis requires GrnA proteolysis. GrnA-induced membrane perturbation, nuclear condensation, and DNA damage are unimpaired by caspase blockade. GrnA fails to induce cleavage of caspase-3, lamin B, rho-GTPase, or PARP. GrnA-induced cytotoxicity and cleavage of PHAP II, a previously identified GrnA substrate, are unimpaired in Jurkat cells that overexpress bcl-2. Therefore, GrnA activates a novel apoptotic pathway.

Potential effect of authorization bias on medical record research

OBJECTIVE

To analyze the influence of recent changes in Minnesota statutes that generally require prior authorization for use of medical records for research from patients who received medical care after Jan. 1, 1997.

MATERIAL AND METHODS

In this Mayo Clinic Institutional Review Board-approved study, we obtained a stratified random sample of patients encountered at Mayo Clinic Rochester during the period 1994 through 1996 and estimated the proportion willing to provide the general authorization. On the basis of data from administrative files, we then compared demographic, diagnostic, and utilization characteristics for patients who provided authorization and those who did not.

RESULTS

Overall, 3.2% (95% confidence interval, 2.4 to 4.0%) of the study subjects declined authorization. If patients not responding to requests for authorization were also considered to have refused, the overall refusal rate would be 20.7% (95% confidence interval, 18.5 to 22.9%). Women were somewhat more likely to refuse authorization than were men (4.0% versus 2.4%; P = 0.067), and patients younger than 60 years were more likely to refuse than were older patients (5.4% versus 1.2%; P<0.001). Patients residing more than 120 miles from Rochester were much less likely to decline authorization than were local residents (2.1% versus 5.8%; P = 0.001). Patients with prior diagnoses that might be considered more sensitive such as mental disorders, infectious diseases, and reproductive problems also were more likely to refuse authorization.

CONCLUSION

These data demonstrate that laws requiring written authorization for research use of the medical record could result in substantial biases in etiologic and outcome studies, the direction and magnitude of which may vary from topic to topic. Clinicians should be prepared to enter the discussion to help inform patients and legislators of the potential hazards of laws that restrict access to medical records for research purposes.

Effect of lidocaine on improving cerebral protection provided by retrograde cerebral perfusion: a neuropathologic study

OBJECTIVE

To determine whether lidocaine can improve the neuropathologic results in canine brains after retrograde cerebral perfusion (RCP).

DESIGN

Randomized, blinded, experimental study.

SETTING

University animal laboratory.

PARTICIPANTS

Mongrel dogs.

INTERVENTIONS

Fourteen mongrel dogs were placed on 120 minutes of hypothermic (20 degrees C) RCP. Following the RPC, they then resumed cardiopulmonary bypass and rewarming for 60 minutes. In the lidocaine group (n = 8), lidocaine was administered continuously; in the control group (n = 6), normal saline was administered. Cerebral perfusion fixation was performed at the end of the experiment.

MEASUREMENTS AND MAIN RESULTS

The number of ischemic cells in 200 neurons was counted in the parietal cortex, CA1 sector of the hippocampus, CA3 sector of the hippocampus, ventral posterolateral nucleus of the thalamus, and Purkinje cells of the cerebellar cortex. Those in the parietal cortex, CA1 sector of the hippocampus, and ventral posterolateral nucleus of the thalamus were significantly less in the lidocaine group than in the control group (25.8+/-17.3 v 53.7+/-12.0; p < 0.01; 17.0+/-8.5 v 54.7+/-22.1; p < 0.01; and 16.9+/-17.8 v 49.7+/-28.4; p < 0.05, respectively). The total number of ischemic cells in the five examined regions was also significantly less in the lidocaine group than in the control group (89.5+/-19.4 v 219.5+/-45.5; p < 0.01).

CONCLUSION

Continuous lidocaine significantly alleviated the ischemic neuropathologic injury after RCP and thus possibly improved cerebral protection.

Cloning, in vitro expression, and novel phylogenetic classification of a channel catfish estrogen receptor

We obtained two channel catfish estrogen receptor (ccER) cDNA from liver of female fish using RT-PCR. The two fragments were identical in sequence except that the smaller one had an out-of-frame deletion in the E domain, suggesting the existence of ccER splice variants. The larger fragment was used to screen a cDNA library from liver of a prepubescent female. A cDNA was obtained that encoded a 581-amino-acid ER with a deduced molecular weight of 63.8 kDa. Extracts of COS-7 cells transfected with ccER cDNA bound estrogen with high affinity (Kd = 4.7 nM) and specificity. Maximum parsimony and Neighbor Joining analyses were used to generate a phylogenetic classification of ccER on the basis of 18 full-length ER sequences. The tree suggested the existence of two major ER branches. One branch contained two clearly divergent clades which included all piscine ER (except Japanese eel ER) and all tetrapod ERalpha, respectively. The second major branch contained the eel ER and the mammalian ERbeta. The high degree of divergence between the eel ER and mammalian ERbeta suggested that they also represent distinct piscine and tetrapod ER. These data suggest that ERalpha and ERbeta are present throughout vertebrates and that these two major ER types evolved by duplication of an ancestral ER gene. Sequence alignments with other members of the nuclear hormone receptor superfamily indicated the presence of 8 amino acids in the E domain that align exclusively among ER. Four of these amino acids have not received prior research attention and their function is unknown. The novel finding of putative ER splice variants in a nonmammalian vertebrate and the novel phylogenetic classification of ER offer new perspectives in understanding the diversification and function of ER.

TL1, a novel tumor necrosis factor-like cytokine, induces apoptosis in endothelial cells. Involvement of activation of stress protein kinases (stress-activated protein kinase and p38 mitogen-activated protein kinase) and caspase-3-like protease

TL1 is a recently discovered novel member of the tumor necrosis factor (TNF) cytokine family. TL1 is abundantly expressed in endothelial cells, but its function is not known. The present study was undertaken to explore whether TL1 induces apoptosis in endothelial cells and, if so, to explore its mechanism of action. Cultured bovine pulmonary artery endothelial cells (BPAEC) exposed to TL1 showed morphological (including ultrastructural) and biochemical features characteristic of apoptosis. TL1-induced apoptosis in BPAEC was a time- and concentration-dependent process (EC50 = 72 ng/ml). The effect of TL1 was not inhibited by soluble TNF receptors 1 or 2. TL1 up-regulated Fas expression in BPAEC at 8 and 24 h after treatment, and significantly activated stress-activated protein kinase (SAPK) and p38 mitogen-activated protein kinase (p38 MAPK). The peak activities of SAPK and p38 MAPK in TL1-treated BPAEC were increased by 9- and 4-fold, respectively. TL1-induced apoptosis in the BPAEC was reduced by expression of a dominant-interfering mutant of c-Jun (62.8%, p < 0.05) or by a specific p38 inhibitor, SB203580 (1-10 microM) dose-dependently. TL1 also activated caspases in BPAEC, and TL1-induced apoptosis in BPAEC was significantly attenuated by the caspase inhibitor, ZVAD-fluromethyl-ketone. The major component activated by TL1 in BPAEC was caspase-3, which was based on substrate specificity and immunocytochemical analysis. These findings suggest that TL1 may act as an autocrine factor to induce apoptosis in endothelial cells via activation of multiple signaling pathways, including stress protein kinases as well as certain caspases.

[Relationship between endothelin-1 and ischemic brain damage after subarachnoid hemorrhage and protective effect of Ginkgo biloba extract]

OBJECTIVE

To investigate the role of endothelin-1 (ET-1) in development of ischemic brain damage after subarachnoid hemorrhage (SAH), and the protective effect of Ginkgo biloba extract (GBE).

METHODS

Wistar rat noncraniotomy models of SAH were divided into SAH group and GBE treated group, the diameter of basilar artery (BA) and dynamic changes of regional cerebral blood flow (rCBF) and ET-1 content of intracranial plasma within 24 hours after SAH of both groups were determined. And pathological examination of CA1 region of hippocampus was performed 3 days later.

RESULTS

rCBF decreased and ET-1 content increased obviously and retained in 24 hours after SAH. Spasm of BA occurred half an hour after SAH and neurons of hippocampus CA1 region was damaged severely. GBE could antagonize the above-mentioned pathological changes effectively.

CONCLUSION

Increase of ET-1 is an important factor leading to ischemic brain damage after SAH. GBE exerts its protective effect by antagonizing pathological increase of ET-1.

The impact of requiring patient authorization for use of data in medical records research

BACKGROUND

In 1996, the Minnesota legislature passed a medical data privacy act requiring patient authorization for the use of medical records in research. Other state legislatures and Congress are considering similar legislation. The impact of this statute on a researcher's ability to obtain complete and representative data is unknown.

METHODS

This was a cross-sectional study of all patients visiting the outpatient clinic, emergency department, or hospital of the Olmsted Medical Center (OMC), for an appointment or admission during January 1997 or February 1997. Patients were asked to give consent for the use of their medical records for research. Our objective was to gather information on the number and characteristics of patients who refused authorization.

RESULTS

Of the 15,997 patients: 90.6% granted authorization; 3.6 refused authorization; 4.5% were undecided; and 1.3% were not asked for authorization. Refusal rates were highest among patients visiting the center for mental health concerns, trauma, or eye care, and among women aged 39 years or older. Undecided rates were highest in women presenting for pregnancy care.

CONCLUSIONS

Refusal rates were low for this community practice. However, higher refusal rates in some subgroups, such as older women or patients with mental health concerns, may increase the chance of selection bias in studies involving these patients.

Lidocaine improving the cerebral protection by retrograde cerebral perfusion

OBJECTIVE

To determine whether lidocaine can improve the cerebral protection provided by retrograde cerebral perfusion.

METHODS

Sixteen mongrel dogs were placed on cardiopulmonary bypass and cooled to 20 degrees C. Retrograde cerebral perfusion was then carried out for 120 minutes, with the external jugular venous pressure kept at 3.33 kPa. Cardiopulmonary bypass was resumed, and the animals were rewarmed to 36 degrees C. The animals were divided into two groups. In the lidocaine group (n = 8), lidocaine was administrated continuously throughout the experiment. In the control group (n = 8), normal saline was given at the same rate.

RESULTS

In both groups, cerebral tissue creatine phosphate and adenosine triphosphate concentrations and energy charge increased by the end of hypothermic cardiopulmonary bypass, decreased continuously during retrograde cerebral perfusion, and recovered gradually after resuming cardiopulmonary bypass. Nevertheless, they recovered to significantly higher levels in the lidocaine group than in the control group (creatine phosphate: 2.44 +/- 0.53 versus 1.61 +/- 0.49 mumol/g wet weight, P = 0.006; adenosine triphosphate: 0.71 +/- 0.18 versus 0.50 +/- 0.17 mumol/g wet weight, P = 0.029; energy charge: 0.59 +/- 0.10 versus 0.48 +/- 0.09, P = 0.044) by the end of the experiment. There was no significant difference between the two groups in the cerebral tissue water content (control group: 77.6% +/- 1.9%; lidocaine group: 77.6% +/- 1.3%).

CONCLUSION

Continuous lidocaine infusion accelerates the recovery of cerebral tissue high energy phosphate contents after resuming cardiopulmonary bypass, but it has no effect on the formation of cerebral edema after retrograde cerebral perfusion.

The purification and identification of heme oxygenase isoforms from spleen tissue of rat and the expression of heme oxygenase-1 cDNA in COS-1 cells

OBJECTIVE

To demonstrate that heme oxygenase (HO) isoforms exist in rat spleen treated with hematin and phenylhydrazine and to confirm that the isolated cDNA actually encodes HO-1 by expressing cDNA in monkey kidney cells (COS-1 cells) in order to prepare HO-1 mutant for inhibiting the natural enzyme.

METHODS

The rat spleen microsomal fractions were first purified by diethylaminoethyl (DEAE)-Sephacel and hydroxylapatite. The activity of two isoforms (HO-1 and HO-2) of enzyme and their apparent molecular weight on sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (SDS-PAGE) were measured. Secondly, using the isolated HO-1 cDNA clone, the expression plasmid pcDNA3HO1 was constructed and transfected into cultured COS-1 cells. The transfected cells were collected and disrupted by sonication, and the microsomes were prepared by ultracentrifugation. The activity of HO-1 was measured.

RESULTS

Two isoforms were purified and identified in treated rat spleen and HO-1 was the predominant form. The ratio of HO-1 to HO-2 was 3.2:1. The apparent molecular weights of HO-1 and HO-2 were about 30 kD and 36 kD under reducing conditions, respectively. The HO-1 was highly expressed in endoplasmic reticulum of transfected cells. The specific band was located in molecular weight of 30 kD. The specific activity was five times higher than that of the control.

CONCLUSION

The activity of expressed HO-1 in COS-1 cells is higher than that of purified enzyme from rat spleen tissue. It is suggested that this clone having an insert of 1030 base-pairs encodes HO-1 and that we can prepare HO-1 mutant by site-directed mutagenesis of HO-1 cDNA to prevent and treat hyperbilirubinemia.

Expression of signal transducers and activators of transcription proteins in acute myeloid leukemia blasts

Hematopoietic cytokine receptor signaling pathways involve activation of signal transducers and activators of transcription (STAT) proteins, which are postulated to be involved in cellular differentiation. Aberrant STAT isoforms (beta forms rather than the normal alpha forms) have been described and have been found to block the normal signaling pathway from the receptor. Bcr/Abl proteins have been suggested to directly activate STATs, without exposure to growth factors. We asked whether STATs play a role in leukemogenesis. We analyzed constitutive and induced patterns of STAT activity in pretreatment blasts from 36 newly diagnosed acute myeloid leukemia (AML) patients and studied protein tyrosine kinases (PTKs) that may be involved in STAT activity, using in vitro and in-gel kinase assays. The beta forms were expressed in 21 of 27 samples (78%). Constitutive STAT3 and STAT5 activity was found in samples from 28 and 22% of patients, respectively. Response to exogenous cytokines identified two groups. STAT activity in one group was modulated by exogenous cytokines: constitutive STAT activity increased in some patients but decreased or disappeared in response to cytokines in others. The second group was cytokine insensitive. Additionally, we found constitutive PTK activity in two patients whose blasts demonstrated constitutive STAT activity, suggesting that PTKs use cytokine receptor signal pathways to activate STATs in AML blasts without exposure to exogenous cytokines. Our data suggest that (a) constitutive expression of aberrant STATs may be involved in blocking differentiation of AML blasts, (b) exogenous cytokines may activate STAT-inhibitory pathways, and (c) STATs may be activated by PTKs in some AML blasts.

Structure and properties in solution of PsaD, an extrinsic polypeptide of photosystem I

PsaD is a small, extrinsic polypeptide located on the stromal side (cytoplasmic side in cyanobacteria) of the photosystem I reaction centre complex. The gene from the cyanobacterium Nostoc sp. PCC 8009 was expressed in Escherichia coli and the structure of the recovered protein in solution investigated. Size-exclusion chromatography, dynamic light scattering and measurement of 15N transverse relaxation times showed that the protein is a stable dimer in solution, whereas in the reaction centre complex it is a monomer. NMR experiments showed that the dimer is symmetrical and that there are at least two domains, one structured and the remainder unstructured. The structured domain contains a small amount of beta-sheet. Three-dimensional heteronuclear NMR spectra of [13C, 15N]PsaD showed that the structured domain is associated with the central part of the sequence while the N- and C-terminal regions are mobile. Evidence was obtained for a shift in equilibrium between two slightly different conformational states at about pH 6, and the protein was shown to bind to PsaE preferentially at neutral pH. Addition of trifluoroethanol was shown to induce the formation of a small amount of alpha-helix, and the form present in 30% trifluoroethanol appears to be more closely related to the in situ structure, which has been reported to contain one short helix in crystals [Schubert, W.-D., Klukas, O., Krauss, N., Saenger, W., Fromme, P. & Witt, H. T. (1997) J. Mol. Biol. 272, 741-769]. The significance of these findings for the assembly of the complex is discussed.

[DPOAE in high-risk neonatal screening for hearing]

64 neonates under intensive care have been tested by distortion product otoacoustic emission (DPOAE) and the auditory brain stem response (ABR) to investigate the value of DPOAE as a test for hearing impairment. The DPOAE test has been found to be practical and quick to perform. The proportion of NICU infants producing a recordable DPOAE is 83.6%, and the sensitivity and specificity to the ABR result is 92.4% and 92.2%, false positive is 7.8%, false negative is 7.6% respectively. These figures are high enough and the reduction in time compared to ABR is sufficient for the DPOAE to be considered as the primary screen, firm conclusions on the sensitivity of DPOAE to long term hearing impairment await the results from larger numbers of infants and further follow up data.

Expression of matrix metalloproteinase-9 mRNA in osteoporotic bone tissues

Matrix metalloproteinases (MMPs), a sort of important enzymes involved in extracellular matrix metabolism, play critical roles in the process of tissues remodeling, wound healing and metastasis of tumors. Dot blot and in situ hybridization were used in this study to detect the expression and localization of MMP-9, an important proteolytic enzyme implicated in bone resorption in bone tissues. The results showed that the level of MMP-9 mRNA expression in osteoporotic bone tissues was significantly higher than that in normal control group and the cell types that expressed MMP-9 mRNA included mono- and multi-nuclear osteoclasts and some lining cells on the surface of bone matrix. It was suggested that MMP-9 play a key role in the development of bone loss in osteoporosis.

[Studies on the fermentation technology of microbiological preparation No.633]

This paper reports the fermentation techmology of bacterial feed No.633. A new fermentational technic, which was composed of fermentation medium, optimum pH, temperature, airate flow, pot pressure and fermentation time, was established.

Expression of type-I collagen and matrix metalloproteinase-9 mRNA in bone of castrated adult female rats: effects of estrogen

OBJECTIVES

To elucidate the molecular changes of bone collagen during the development of postmenopausal osteoporosis and to investigate the molecular effects of estrogen replacement.

METHODS

An adult ovariotomy rat model was used. Type-I collagen and matrix metalloproteinase-9 (MMP-9) expressions in bone tissues of rats treated by sham surgery (SH), bilateral ovariotomy (OVX) and OVX with estradiol (OVX-E2) were analysed at mRNA level by using dot blot technique. The distribution of mRNA of these two genes in bone tissues was studied by in situ hybridization.

RESULTS

The expression levels of both type-I collagen and MMP-9 in bone tissues of OVX rats were higher than those of SH group, while treated with estradiol, the expression of both genes declined to some degree. In situ hybridization showed that type-I collagen mRNA located in osteoblasts, whereas MMP-9 was mainly expressed in osteoclasts, some lining cells on bone surface, and some mononuclear cells in bone marrow.

CONCLUSIONS

The reduction of high bone turnover in osteoporotic bone tissues induced by estrogen replacement may result from alterations in gene expression related to bone formation and bone resorption. These alterations are consistent with the changes observed previously by histomorphometry and biochemical markers of bone metabolism on OVX animals and postmenopausal osteoporosis.

Microencapsulation of rat islets prolongs xenograft survival in diabetic mice

OBJECTIVE

To protect the transplanted islets from the host's immune system by means of immunoexclusion membranes.

METHODS

Rat islets were isolated from Wistar rat pancreas by ductal collagenase distention, stationary digestion, and finally with the aid of dextran gradient separation. Then the islets were encapsulated in alginate-polylysine-alginate (APA) semipermeable membranes.

RESULTS

In vitro studies demonstrated that encapsulated islets secreted insulin in response to glucose challenge for at least 8 weeks, which was similar to free islets. In vivo studies showed that 15 streptozotocin (STZ)-induced diabetic mice were transplanted intraperitoneally with 1000 encapsulated islets without immunosuppression. Diabetes was reversed within 3 days, and the mice remained normoglycemic for up to 160 days, with a mean xenograft survival time of 126 days. The encapsulated islets had a significantly greater effect than unencapsulated islets, which functioned for less than 8 days.

CONCLUSIONS

Encapsulation of pancreatic islets in semipermeable membranes can effectively prolong xenograft survival without immunosuppression in an animal model.

Development and characterization of monoclonal antibody to T-antigen: (gal beta1-3GalNAc-alpha-O)

The saccharide antigen, Gal beta1-3GalNAc or T antigen, is of biologic importance in many systems. It is a tumor-associated carbohydrate antigen, a temporally expressed antigen in germinal center B cells and cortical T cells, a parasite-associated antigen, a spermatozoa vitality marker and an antigen on aged red blood cells. It may play a role in normal cellular adhesion and in tumor cell metastasis. Well characterized monoclonal antibodies (MAb) to Gal beta1-3GalNAc will be useful for further studies in these areas. We developed an IgG3 MAb to Gal beta1-3GalNAc by immunizing the mice with a synthetic Gal beta1-3GalNAc-BSA conjugate. The MAb was analyzed using inhibition enzyme immunoassays with related synthetically prepared sugars to determine the restrictions involved in the antibody binding. Use of synthetic sugars as competitors enabled us to delineate the epitope restrictions on the binding activity of this monoclonal and will enable use of this MAb in studies concerning the biologic importance of this disaccharide.

Recovering and reamplifying of the differentially expressed cDNA bands isolated from mRNA differential display. A modified method

Methods for retrieving and reamplifying the differentially expressed cDNA bands have been modified. Direct reamplification of differentially expressed bands after cutting from a polyacrylamide gel (PAG) followed by a simple rinse and crush step has proved to be more convenient and effective than the traditional glycogen-precipitation method. Combination of 30 cycles of differential display (DD) polymerase chain reaction (PCR) and 20 cycles of standard PCR reaction also yielded higher reamplification rates.

Nerve growth factor activates extracellular signal-regulated kinase and p38 mitogen-activated protein kinase pathways to stimulate CREB serine 133 phosphorylation

The mechanisms by which growth factor-induced signals are propagated to the nucleus, leading to the activation of the transcription factor CREB, have been characterized. Nerve growth factor (NGF) was found to activate multiple signaling pathways that mediate the phosphorylation of CREB at the critical regulatory site, serine 133 (Ser-133). NGF activates the extracellular signal-regulated kinase (ERK) mitogen-activated protein kinases (MAPKs), which in turn activate the pp90 ribosomal S6 kinase (RSK) family of Ser/Thr kinases, all three members of which were found to catalyze CREB Ser-133 phosphorylation in vitro and in vivo. In addition to the ERK/RSK pathway, we found that NGF activated the p38 MAPK and its downstream effector, MAPK-activated protein kinase 2 (MAPKAP kinase 2), resulting in phosphorylation of CREB at Ser-133. Inhibition of either the ERK/RSK or the p38/MAPKAP kinase 2 pathway only partially blocked NGF-induced CREB Ser-133 phosphorylation, suggesting that either pathway alone is sufficient for coupling the NGF signal to CREB activation. However, inhibition of both the ERK/RSK and the p38/MAPKAP kinase 2 pathways completely abolished NGF-induced CREB Ser-133 phosphorylation. These findings indicate that NGF activates two distinct MAPK pathways, both of which contribute to the phosphorylation of the transcription factor CREB and the activation of immediate-early genes.

Secular changes in radical prostatectomy utilization rates in Olmsted County, Minnesota 1980 to 1995

PURPOSE

We estimated the changes in utilization of radical prostatectomy for treatment of prostate cancer and describe the clinical characteristics of men undergoing radical prostatectomy in a population based setting.

MATERIALS AND METHODS

The Rochester Epidemiology Project was used to identify all Olmsted County residents who underwent radical prostatectomy from 1980 to 1995. The community medical records of these men were reviewed to determine the clinical and pathological stage and grade at biopsy and following surgery.

RESULTS

From 1980 to 1995, 311 radical prostatectomies were performed on Olmsted County men. From 1980 to 1987 prostatectomy rates ranged from 6.3 to 31.0/100,000 men but rates increased dramatically to 53.6/100,000 in 1988 and 106.2/100,000 in 1992. The rate after 1992 decreased to 53.0/100,000 and then increased slightly to 80.4/100,000. There was a shift to younger age in more recent times (mean patient age 65.4 years in 1980 to 1986 and 62.4 in 1993 to 1995, p = 0.02), a nonsignificant (p = 0.10) trend toward lower pathological stage in recent years (42% stage pT2 in 1980 to 1986 versus 55% in 1993 to 1995) and a significant decrease in the proportion of cases of disease up staged following surgery (53% in 1980 to 1986 versus 37% in 1993 to 1995, p = 0.03). There was no significant trend in pathological grade with time (63% Mayo grade I or II in 1980 to 1986 versus 52% in 1993 to 1995, p = 0.30).

CONCLUSIONS

These findings demonstrate an increase in radical prostatectomy rates that coincided with increases in prostate cancer incidence. There was a decrease in population prostatectomy rates in 1993 which was followed by modest increases to levels lower than the peak in 1992. However, the clinical characteristics of patients during this period did not change dramatically, suggesting that in a population based setting the selection factors for patients undergoing surgical treatment may not have changed.

Expression and purification of enzymatically active recombinant granzyme B in a baculovirus system

Granzyme B (GranB), a serine protease stored in the granules of cytotoxic T lymphocytes and natural killer cells, can initiate target cell apoptosis. To produce large amounts of purified active enzyme, recombinant murine granzyme B (rGranB) was expressed from baculovirus in insect cells. The expressed rGranB is secreted into the culture medium and can be readily purified to homogeneity by one-step affinity chromatography to yield 1.5 mg enzyme per liter insect cell medium. RGranB is recognized by a GranB-specific anti-peptide antibody and is active against synthetic substrate Boc-Ala-Ala-Asp-SBzl with kinetic constant (kcat/Km 45,000 M-1s-1) comparable to purified human GranB, RGranB processes the caspase pro-CPP32 into its enzymatically active form and induces DNA fragmentation in isolated nuclei in the presence of cytosolic factors. The ability to express enzymatically active rGranB using the baculovirus system will help elucidate the role of this granzyme in the immune response.

Biodegradation of tricalcium phosphate ceramics by osteoclasts

Biodegradation of tricalcium phosphate (TCP) ceramics was observed through mixed culture of osteoclasts and TCP discs in vitro in this study. Osteoclasts were isolated from newborn SD rat's marrow of long bone and cultured on TCP discs. The culture terminated at the 48th h and 96th h respectively. Under an inverted microscope, the osteoclasts imparted round or oval body with multinuclear and many thin processes. These cells were positively stained for tartrate-resistance acid phosphatase (TRAP). Scanning electron microscope showed that many resorption lacunae on TCP disc surface and their diameters were smaller than 20 microns. Osteoclasts were located in the lacunae. At the 96th h, the resorption lacunae become larger and osteoclasts showed degeneration. It is suggested that osteoclasts possess ability to re-absorb TCP ceramics under in vitro culturing condition.

[The check and trouble shoot of mA trouble of shimadzu X-ray generator HD150B-10]

X-ray machine mA circuits are generally composed by mA Pre-set circuits and mA detect circuits. To effectively control the tube current, there are many safety circuits and auxiliary circuits in mA control circuits. The trouble of mA circuits of HD150B-10 displays "mA Trouble" promptly on the plasma display; however, it is difficult to discover the actual trouble in the circuits because the mA control circuits are interconnected. In this paper, the question we discuss is how to check and shoot quickly and correctly the trouble of mA circuits, after the prompt appearance of "mA Trouble" on the plasma display.

Tricyclic antidepressants induce apoptosis in human T lymphocytes

Apoptosis is a form of programmed cell death that is involved in cell turnover. In the present study we show that the tricyclic antidepressants (TCAS) imipramine, clomipramine and citalopram induce apoptosis in human peripheral lymphocytes. Lymphocytes were incubated with these three drugs for up to 48 h. Apoptosis was characterized by typical nucleosomal DNA fragmentation on agarose gel, as well as quantitated using 4'-6-diamidino-2-phenylindole (DAPI) staining and 3'-OH end-labeling of fragmented DNA at the single cell level. Apoptosis induced by TCAs was shown to be dose-dependent and could be detected after a 24 h incubation. The optimal concentrations of the three TCAs found to induce apoptosis were 50 microM imipramine, 20 microM clomipramine and 180 microM citalopram. Furthermore, immunofluorescence and three-color flow cytometry were used to identify the phenotype of apoptotic cells. TCA-induced apoptosis was shown to involve exclusively T-lymphocytes. Cytotoxic T-lymphocytes were more prone to undergo apoptosis than were T-helper cells. In conclusion, the present investigation clearly demonstrates that TCAs exert cell biological effects upon human T-lymphocytes. Further studies are required to determine the possible clinical relevance of these findings.

Modified Evans blue fluorimetry for determination of pulmonary vascular permeability in rats sustaining burns, and delayed fluid resuscitation of burn shock

The present experiment used modified Evans blue fluorimetry to determine changes in pulmonary vascular permeability using a delayed resuscitation model of burn shock in rats. The results showed that pulmonary vascular permeability in the immediate resuscitation (IR) group regressed to normal 12-24 h following the burn whereas it regressed slowly in the delayed resuscitation (DR) group. The study showed that Evans blue fluorimetry is a reliable and sensitive method for determining pulmonary vascular permeability, and dimethyl formamide is a preferable extracting solution which provides a quick and convenient means for scientific research.

A cytoplasmic inhibitor of the JNK signal transduction pathway

The c-Jun amino-terminal kinase (JNK) is a member of the stress-activated group of mitogen-activated protein (MAP) kinases that are implicated in the control of cell growth. A murine cytoplasmic protein that binds specifically to JNK [the JNK interacting protein-1 (JIP-1)] was characterized and cloned. JIP-1 caused cytoplasmic retention of JNK and inhibition of JNK-regulated gene expression. In addition, JIP-1 suppressed the effects of the JNK signaling pathway on cellular proliferation, including transformation by the Bcr-Abl oncogene. This analysis identifies JIP-1 as a specific inhibitor of the JNK signal transduction pathway and establishes protein targeting as a mechanism that regulates signaling by stress-activated MAP kinases.

Biorheological features of some soft tissues under a surgical tissue expansion procedure

The aim of this study was to investigate the effects of a surgical tissue expansion procedure on the biomechanical features of the expanded soft tissues. In this procedure a silicone balloon "expander" is surgically inserted into a tissue and inflated. The tissue mass increases under the stretch of the expander. The increased tissue can then be used as an autologous source for the surgical reconstruction of organs. In this article, dog saphenous neurovascular bundle was used. Expanded saphenous nerves, arteries and veins were harvested and their biomechanical features and ultrastructural, histological changes were studied. The stress relaxation features, the continuous spectrum of relaxation time, and the stress-strain relationship of expanded and control specimens were measured. Results show that within two or three weeks after placement of the expanders, the biomechanical properties of expanded saphenous nerves, arteries and veins began to deviate from those of their controls, and the differences between them were proportional to the volume of inflation; but when the expanding period was 15 weeks or longer, the properties of expanded specimens and their controls became close again. Histological study showed that the content of collagenous fibers in blood vessel walls decreased after expansion. The content of elastic fibers in blood vessel walls first increased, then returned to normal, and finally decreased. Ultrastructural studies showed that when elongated by 25-40%, the expanded nerves had well preserved axons and showed fewer smooth myelin sheaths only in the middle and distal part of the expansion.

[Comparative study of two fusion retinoic acid receptor alpha in acute promyelocytic leukemia]

OBJECTIVE

To make a comparison of biological properties between PML-RARalpha and PLZF-RARalpha fusion proteins.

METHODS

Receptor radioligand binding assay, receptor DNA binding assay and immunofluorescence methods were used.

RESULTS AND CONCLUSION

PML-RARalpha and PLZF-RARalpha had similar ligand-binding affinities. Both could bind in vitro to retinoic acid response elements (RAREs) forming homodimers and to retinoic acid X receptor. However ,they differed in the relative binding affinities to different RAREs,the behavior of forming complex with RXR and the subcellular localization. More importantly, PML-RARalpha and PLZF-RARalpha could block different regulatory pathways mediated by PML or PLZF, through heterocomplex formation with wild-type PML or PLZF. The differences between PML-RARalpha and PLZF-RARalpha may in part explain the apparent resistance of APL with t(11;17) to differentiating effect of all-trans retinoic acid (ATRA).

Calmodulin-regulated adenylyl cyclases and neuromodulation

Coincidence detection and crosstalk between signal transduction systems play very important regulatory roles in the nervous system, particularly in the regulation of transcription. Coupling of the Ca2+ and cAMP regulatory systems by calmodulin-regulated adenylyl cyclases is hypothesized to be important for some forms of synaptic plasticity, neuroendocrine function, and olfactory detection. Recent studies of a mutant mouse deficient in type I calmodulin-sensitive adenylyl cyclase have provided the first evidence that adenylyl cyclases are important for synaptic plasticity, as well as for learning and memory in vertebrates.

Tricyclic antidepressant-induced lipidosis in human peripheral monocytes in vitro, as well as in a monocyte-derived cell line, as monitored by spectrofluorimetry and flow cytometry after staining with Nile red

Human mono- and lymphocytes from peripheral blood and the monoblastoid cell line U-937 were used in this in vitro study of drug-induced lipidosis. Mono- and lymphocytes were exposed for 4 days to three different tricyclic antidepressants (TCAs), imipramine (25 microM), clomipramine (10 microM) and citalopram (80 microM). The lipophilic fluorophore Nile red, which stains intracellular lipid structures selectively, was used as a lipid probe. Fluorescence microscopy, spectrofluorimetry and flow cytometry were used to detect cellular lipidosis, as verified by electron microscopy. Our results demonstrate that imipramine, clomipramine and citalopram induce lipidosis in monocytes and U-937 cells, but not in lymphocytes. An accurate quantitation of induced intracellular lipidosis can be achieved by spectrofluorimetric and flow cytometric analysis.

Glucocorticoids inhibit the cytokine-induced proliferation of mast cells, the high affinity IgE receptor-mediated expression of TNF-alpha, and the IL-10-induced expression of chymases

Mast cells are a heterogeneous family of immune cells that, when activated through their high affinity IgE receptors (Fc epsilonRI), release various granule mediators (e.g., neutral proteases and serglycin proteoglycans) and proinflammatory cytokines (e.g., IL-6 and TNF-alpha). We and others have shown that the growth and differentiation of immature, nontransformed mouse bone marrow-derived mast cells (mBMMC) can be regulated in vitro by IL-3, IL-10, and c-kit ligand. We now report that glucocorticoids inhibit the c-kit ligand- and IL-3-induced proliferation of mBMMC, the Fc epsilonRI-mediated expression of TNF-alpha, and the IL-10-mediated expression of the two chymases designated mouse mast cell protease (mMCP)-1 and mMCP-2. In contrast, glucocorticoids induce mBMMC to increase their expression of serglycin proteoglycan and carboxypeptidase A. As assessed by nuclear run-on and RNA blot analyses, dexamethasone inhibited the IL-10-mediated expression of mMCP-1 and mMCP-2, primarily by inducing rapid degradation of their transcripts. The stimulative effect on serglycin proteoglycan expression and the inhibitory effect on chymase expression were dose and time dependent and glucocorticoid specific. These findings indicate that glucocorticoids exert profound and diverse effects on the growth, cytokine expression, and granule differentiation of mouse mast cells, and that at least some of this regulation occurs through a post-transcriptional mechanism.

NMR relaxation studies on hepatic intracellular and extracellular sodium in rats with burn injury

In vivo longitudinal (T1) and transverse (T2) relaxation times of hepatic intracellular and extracellular sodium were studied in rats with sham burn or burn injury with 23Na NMR spectroscopy and shift reagent. Burn injury decreases hepatic extracellular sodium content by 17% compared with sham burn, whereas it increases the percent of the fast T2 component of extracellular sodium, suggesting an increase in the fraction of bound Na+/- sites in the extracellular space. It is interesting that the relaxation characteristics of intracellular sodium remained unchanged despite a 57% increase in intracellular sodium content, suggesting the increase in intracellular free sodium is matched by either a proportional increase in intracellular bound sodium or an uncovering of ordered domain sites that can preferentially orient rapidly exchanging sodium ions. This study also demonstrated that spin lattice (T1) relaxation rates or the percent contribution of the fast/slow T2 components of the combined intracellular/extracellular 23Na signal (before the infusion of shift reagent) may also be sensitive to changes in intracellular sodium levels during pathologic changes.

Glucocorticoids inhibit the cytokine-induced proliferation of mast cells, the high affinity IgE receptor-mediated expression of TNF-alpha, and the IL-10-induced expression of chymases

Mast cells are a heterogeneous family of immune cells that, when activated through their high affinity IgE receptors (Fc epsilonRI), release various granule mediators (e.g., neutral proteases and serglycin proteoglycans) and proinflammatory cytokines (e.g., IL-6 and TNF-alpha). We and others have shown that the growth and differentiation of immature, nontransformed mouse bone marrow-derived mast cells (mBMMC) can be regulated in vitro by IL-3, IL-10, and c-kit ligand. We now report that glucocorticoids inhibit the c-kit ligand- and IL-3-induced proliferation of mBMMC, the Fc epsilonRI-mediated expression of TNF-alpha, and the IL-10-mediated expression of the two chymases designated mouse mast cell protease (mMCP)-1 and mMCP-2. In contrast, glucocorticoids induce mBMMC to increase their expression of serglycin proteoglycan and carboxypeptidase A. As assessed by nuclear run-on and RNA blot analyses, dexamethasone inhibited the IL-10-mediated expression of mMCP-1 and mMCP-2, primarily by inducing rapid degradation of their transcripts. The stimulative effect on serglycin proteoglycan expression and the inhibitory effect on chymase expression were dose and time dependent and glucocorticoid specific. These findings indicate that glucocorticoids exert profound and diverse effects on the growth, cytokine expression, and granule differentiation of mouse mast cells, and that at least some of this regulation occurs through a post-transcriptional mechanism.

The risk of ectopic pregnancy after tubal sterilization. U.S. Collaborative Review of Sterilization Working Group

BACKGROUND

Tubal sterilization is an increasingly common method of contraception in the United States. Although pregnancy after sterilization is uncommon, it can occur and may be ectopic. We used data from the U.S. Collaborative Review of Sterilization to estimate the risk of ectopic pregnancy in women who had undergone the common types of tubal sterilization.

METHODS

A total of 10,685 women undergoing tubal sterilization were followed in a multicenter, prospective cohort study. We intended to follow all the women for 5 years by means of annual telephone interviews; for women enrolled early in the study, we attempted an additional follow-up telephone interview 8 to 14 years after sterilization. To assess the risk of ectopic pregnancy in these women, we used cumulative life-table probabilities and proportional-hazards analysis.

RESULTS

There were 47 ectopic pregnancies in the 10,685 women; the 10-year cumulative probability of ectopic pregnancy for all methods of tubal sterilization combined was 7.3 per 1000 procedures. The cumulative probability varied substantially according to the method of sterilization and the woman's age at the time of sterilization. Women sterilized by bipolar tubal coagulation before the age of 30 years had a probability of ectopic pregnancy that was 27 times as high as that among women of similar age who underwent postpartum partial salpingectomy (31.9 vs. 1.2 ectopic pregnancies per 1000 procedures). The annual rate of ectopic pregnancy for all methods combined in the 4th through 10th years after sterilization was no lower than that in the first 3 years.

CONCLUSIONS

A history of tubal sterilization does not rule out the possibility of ectopic pregnancy, even many years after the procedure.

[The preliminary study on prevention and treatment of neonatal jaundice]

OBJECTIVE

The purification and identification of heme oxygenase isoforms (HO-1) and HO-2 from human liver were described and Sn-protoporphyrin (SnPP) was used to inhibit HO-1 activity in order to provide a new method for prevention and treatment of neonatal jaundice.

METHODS

Human hepatic microsomal fractions were purified by DEAE-Sephadex A-25 and hydroxylapatite chromatography. The enzyme activities of the two isoforms were detected with and without Snpp.

RESULTS

HO-1 was the predominant form with a ratio of 2.4:1 (HO-1:HO-2). The apparent molecular weight of HO-1 and HO-2 on SDS-PAGE was 30,000 and 36,000 under reducing conditions, respectively. The study also showed that HO-1 was the traditional inducible heme oxygenase and HO-2 was a non-inducible heme oxygenase.

CONCLUSION

The efficient inhibition effect of SnPP on HO-1 is suggested.

Effect of intra-arachnoid space perfusion on thromboxane A and prostacycline in experimental spinal cord injury

In order to understand the relation between TXA2-PGI2 and secondary trauma and the effect of intra-arachnoid perfusion of dexamethasone and verapamil on alteration of TXA2-PGI2 following spinal cord injury, TXB2 and 6-keto-PGF alpha concentration and pathological changes in injured site 1, 2, 4, and 6 h after injury were studied using a rabbit spinal cord injury model by Allen's weight drop method.