CoMFA-based prediction of agonist affinities at recombinant wild type versus serine to alanine point mutated D2 dopamine receptors

Agonist affinity changes dramatically as a result of serine to alanine mutations (S193A, S194A, and S197A) within the fifth transmembrane region of D2 dopamine receptors and other receptors for monoamine neurotransmitters. However, agonist 2D-structure does not predict which drugs will be sensitive to which point mutations. Modeling drug-receptor interactions at the 3D level offers considerably more promise in this regard. In particular, a comparison of the same test set of agonists across receptors differing minimally (point mutations) offers promise to enhance the understanding of the structural bases for drug-receptor interactions. We have previously shown that comparative molecular field analysis (CoMFA) can be applied to comparisons of affinity at recombinant D1 and D2 dopamine receptors for the same set of agonists, a differential QSAR. Here, we predicted agonist K(L) for the same set of agonists at wild type D2 vs S193A, S194A, and S197A receptors using CoMFA. Each model used bromocriptine as the template. ln(1/K(L)) values for the low-affinity agonist binding conformation at recombinant wild type and mutant D2 dopamine receptors stably expressed in C6 glioma cells were used as the target property for the CoMFA of the 16 aligned agonist structures. The resulting CoMFA models yielded cross-validated R(2) (q(2)) values ranging from 0.835 to 0.864 and simple R(2) values ranging from 0.999 to 1.000. Predictions of test compound affinities at WT and each mutant receptor were close to measured affinity values. This finding confirmed the predictive ability of the models and their differences from one another. The results strongly support the idea that CoMFA models of the same training set of compounds applied to WT vs mutant receptors can accurately predict differences in drug affinity at each. Furthermore, in a "proof of principle", two different templates were used to derive the CoMFA model for the WT and S193A mutant receptors. Pergolide was chosen as an alternate template because it showed a significant increase in affinity as a result of the S193A mutation. In this instance both the bromocriptine- and pergolide-based CoMFA models were similar to one another but different from those for the WT receptor using bromocriptine- or pergolide- as templates. The pergolide-based S193A model was more strikingly different from that of the WT receptor than was the bromocriptine-based S193A model. This suggests that a "dual-template" approach to differential CoMFA may have special value in elucidating key differences across related receptor types and in determining important elements of the drug-receptor interaction.

High-throughput single-molecule DNA screening based on electrophoresis

In electrophoresis, the migration velocity is used for sizing DNA and proteins or for distinguishing molecules based on charge and hydrodynamic radius. Many protein and DNA assays relevant to disease diagnosis are based on such separations. However, standard protocols are not only slow (minutes to hours) but also insensitive (many molecules in a detectable band). We successfully demonstrated a high-throughput imaging approach that allows determination of the individual electrophoretic mobilities of many molecules at a time. Each measurement only requires a few milliseconds to complete. This opens up the possibility of screening single copies of DNA or proteins within single biological cells for disease markers without performing polymerase chain reaction or other biological amplification. The purpose is not to separate the DNA molecules but to identify each one on the basis of the measured electrophoretic mobility. We developed three different procedures to measure the individual molecular mobilities. The results correlate well with capillary electrophoresis (CE) experiments for the same samples (2-49 kb dsDNA) under identical separation conditions. The implication is that any electrophoresis protocols from slab gels to CE should be adaptable to single-molecule screening for disease diagnosis.

Effect of ice water ingestion on asthmatic children after exercise challenge

Both exercise and ice water ingestion are known to be trigger factors for an asthma attack in ethnic Chinese asthmatic children. The purpose of this study was to investigate whether ice water ingestion further deteriorates pulmonary function of asthmatic children after exercise. Thirty Chinese asthmatic children underwent exercise challenge by ergocyclometer for 6 minutes and then were further challenged by immediate ingestion of ice water (200 ml, 0-4 degrees C), warm water (200 ml, 37 degrees C) or no ingestion on three different days in one week. Each patient completed the three different water ingestion tests after exercise challenge. The FEV1, FEF25-75%, and PEF tests were performed at baseline and again at 5, 15, 30, 60, 90 minutes after exercise plus water ingestion challenge. After the spirometric test at 90 minutes, 3 puffs (0.6 mg) of hexoprenaline from a metered dose inhaler were given and then a further spirometric test was performed 15 minutes later. The FEV1 and PEF were significantly decreased after exercise plus the 3 different water ingestion challenge except for the FEV1 in the patients who ingested nothing (p = 0.051) and PEF in the patients who ingested warm water (p = 0.163). FEF25-75% of the three tests was not significantly decreased. Exercise-induced asthma (EIA) developed in about two thirds of the 30 patients, regardless of whether ice water, warm water or nothing at all was ingested after exercise challenge. There was no statistically significant difference in spirometric data among the 3 different water tests at various time points. The mean percentage increase of FEV1, FEF25-75% and PEF after bronchodilator therapy were all the lowest in the ice water test, and the greatest in the warm water test. A statistically significant difference was found between ice water and warm water tests for FEV1 and PEF (p = 0.0293 and p = 0.0308 respectively). In conclusion, about two thirds of the asthmatic children in this series had EIA. Those who ingested warm water after exercise had a better bronchodilator response than those who ingested ice water.

Early and late long-term effects of vasectomy on Zn, Cd, and Cu levels in prostatic fluid and serum

AIM

To evaluate the early and late long-term effects of vasectomy on the serum and prostatic fluid trace elements.

METHODS

In 37 vasectomized and 25 non-vasectomized (control) men, the Zn, Cd and Cu levels in the serum and prostatic fluid were measured by means of inductively coupled plasma-atomic emission spectroscopy (ICP-AES).

RESULTS

No significant difference was found in the prostatic Zn, Cd and Cu levels between the vasectomized and control group. The Zn level in the serum were significantly lower in the vasectomized men than in the controls (11.04 and 13.54 umol/L, respectively; P < 0.05), while the serum Cd and Cu levels were not significantly different between the two groups.

CONCLUSION

Vasectomy may decrease the serum, but not the prostatic Zn levels. Its pathophysiological significance is worthy of further investigation.

Effects of cancer therapy on dental and maxillofacial development in children: report of case

Malignant lymphoma is one of the most common hematological diseases of children. The prognosis is fairly good with multimodal cancer therapy. We reported a boy with Burkitt's lymphoma in the nasal cavity who received chemotherapy and irradiation of the head and neck area at four years of age. During seven years of follow-up, we studied the developmental effects of cancer therapy, including general growth, maxillofacial bones, and dentition. Compared with boys of matching age, the development of his entire body and maxillofacial bones was delayed. In the irradiated areas, the roots of teeth were short or poorly developed and the root apices showed premature closure. After the patient was in remission from the tumor in his early childhood, the long-term effects of cancer therapy on dental and maxillofacial development are worth our further evaluation and follow-up.

One- and two-photon-induced fluorescence from recombinant green fluorescent protein

The fluorescence spectral properties of recombinant green fluorescent protein (rGFP) were examined with one- and two-photon excitations using femtosecond pulses from a Ti:sapphire laser. Intensity-dependent properties of the two-photon-induced fluorescence from rGFP excited by an 800-nm, 100-fs laser beam were reported, and the two-photon excitation cross section of rGFP was measured at 800 nm as about 160 x 10(-50) cm(4)s/photon. The possible excited-state proton transfer between two electronic states at about 400 nm in protonated (RH) species and 478 nm in deprotonated (R(-)) species in rGFP was confirmed by fluorescence and fluorescence excitation anisotropy spectra. A subelectronic state (or vibronic progression) at about 420 nm in RH species was identified, which was relatively stable and not involved in the excited state proton transfer in rGFP upon irradiation.

Steroid hormones and bone

Steroid hormones have an important impact on bone. The mechanism of steroid action on bone cells is through an interaction with specific receptor proteins in the target cells. Steroid receptors are a class of molecules that function as both signal transducers and transcription factors. The receptors each have similar functional domains that are responsible for discrete functions. The mechanism of receptor action is mediated by both genomic and nongenomic pathways. It is believed that in genomic pathway the steroid passes through the cell membrane by passive diffusion and binds to the receptor within the nucleus. Steroids have direct action on osteoblasts via receptor, and the effects of steroids on osteoclastic bone resorption are mediated through osteoblasts which release soluble factors by the action of hormone-receptor binding. However, in addition to indirect effects on osteoclasts, the question whether steroid hormones could exert direct action on osteoclasts as well has not to be answered and findings to date are controversial. It is not doubt that understanding the precise molecular mechanism of steroid action on bone resorption will develop new approaches for the diagnosis and treatment of disease associated with osteoclastic bone resorption.

Formulations of controlled atmosphere agents for packaged foods

Four food grade additives-sodium ascorbate, sodium bicarbonate, sodium carbonate-10-hydrate, and ferrous sulfate-7-hydrate-were selected as the basic ingredients to formulate the controlled atmosphere agents which could effectively remove oxygen and release carbon dioxide. The mathematical models giving the relationships between the formulations and the responses (oxygen and carbon dioxide contents) were developed using response surface methodology (RSM). Within 8-24 h, the oxygen and carbon dioxide contents of all tested formulations could reach constant levels, in the ranges of 2-9% and 0-41%, respectively. These formulations were considered to be effective, safe, and easy to prepare and could be applied to wide varieties of food products.

Successful pregnancy after treatment of deep adenomyosis with cytoreductive surgery and subsequent gonadotropin-releasing hormone agonist: a case report

Adenomyosis is a common pathologic finding significantly related to the menstrual and reproductive characteristics of women. Although noted during younger reproductive years, it usually presents in women over 35 years of age. For those with a strong desire to preserve fertility, there is presently no uniform agreement on the most appropriate therapeutic methods to manage the condition. Herein, we present a case of long-term secondary infertility with successful pregnancy after treatment of deep adenomyosis with cytoreductive surgery and a subsequent six-month course of gonadotropin-releasing hormone agonist (GnRHa) therapy. For those who want to conceive, early combined GnRHa therapy immediately following cytoreductive surgery and a delay of four to six months before attempting to fall pregnant is advisable. This is because adenomyosis tends to recur rapidly and the myometrium can be significantly disrupted during surgery. The major obstetric complications, such as uterine atony, rupture or placenta accreta, do not increase with adenomyosis during pregnancy. Although two events of threatened abortion and one of preterm labor were encountered during the pregnancy course, a healthy 2,900-g female was delivered by low transverse cesarean section at term. A cesarean section was performed because of previous large cytoreductive surgery. In contrast to GnRHa therapy alone, we report an effective alternative to hysterectomy in order to maintain fertility and achieve successful pregnancy.

New one-week, low-dose triple therapy for the treatment of duodenal ulcer with Helicobacter pylori infection

BACKGROUND

Antimicrobial therapy is the recommended treatment for duodenal ulcer associated with Helicobacter pylori infection. The eradication of bismuth-based triple therapy with bismuth subcitrate, metronidazole and amoxicillin is limited by low compliance, drug resistance and side-effects. Two-week proton pump inhibitor (PPI)-based triple therapy has a higher eradication rate but is costly. This study was designed to compare the efficacy, patient compliance and cost of short-term PPI-based triple therapy with those of bismuth-based triple therapy.

METHODS

Ninety patients with active duodenal ulcer disease and H pylori infection, proven with the 13C-urea breath test and CLO test (Campylobacter-like organism test) were treated randomly in three therapeutic groups: Group A, DeNol 120 mg, amoxicillin 500 mg and metronidazole 250 mg four times a day orally for 14 days; Group B, omeprazole 20 mg plus clarithromycin 500 mg twice a day and amoxicillin 500 mg four times a day for 14 days; Group C, omeprazole 20 mg, clarithromycin 250 mg and metronidazole 500 mg twice a day for seven days. Nizatidine 150 mg twice a day was given continuously following the end of anti-H pylori therapy for each group. Two months later, endoscopy, the CLO test and 13C-urea breath test were repeated to assess the eradication rate of H pylori and the ulcer-healing rate. Drug tolerance was evaluated by patients themselves by daily recording of any side-effects.

RESULTS

Eighty-four patients completed the entire course of therapy and evaluation for H pylori infection. The H pylori eradication rates in Groups A, B and C were 75% (21/28), 93% (26/28) and 89% (25/28), respectively (p = 0.466). The ulcer healing rate was 86% (24/28) in Group A and 89% (25/28) in Groups B and C (p = 0.764). A total of 74 patients (88%) were free from symptoms at the end of the triple therapy. Symptom relief was faster in patients with PPI-based triple therapy (Groups B and C) (days 3 and 4) than for patients with bismuth-based triple therapy (day 5). The cost of Group C therapy was lower than that for Groups A and B. There were no major side-effects in any of the patients.

CONCLUSIONS

One-week triple therapy with omeprazole, clarithromycin and metronidazole is highly effected for the eradication of H pylori. A therapeutic regime of one week's duration with lower cost, good compliance and mild side-effects may offer a good choice for treatment of duodenal ulcer associated with H pylori infection in clinical practice.

Detection of estrogen receptor alpha, carbonic anhydrase II and tartrate-resistant acid phosphatase mRNAs in putative mononuclear osteoclast precursor cells of neonatal rats by fluorescence in situ hybridization

Increasing evidence suggests that estrogen deficiency in women promotes the expansion of populations of bone marrow cells that differentiate into osteoclasts under the influence of osteotropic hormones and local factors. A progressive cytoplasmic accumulation of osteoclastic bone resorbing enzymes, such as tartrate-resistant acid phosphatase (TRACP) and carbonic anhydrase II (CA II), characterizes osteoclast differentiation. To evaluate the possibility that estrogen may have a direct effect on osteoclast precursor cells, we investigated the mRNA levels of estrogen receptor a (ERa), TRACP and CA II genes in neonatal rat bone imprints by fluorescence in situ hybridization and confocal microscopy. Morphological assessment of bone imprints has shown that the putative mononuclear osteoclast precursor cells (MOPC) display strongly basophilic cytoplasm and a low nuclear/cytoplasmic ratio, while some of these cells possess pale-staining ruffled border regions similar to those observed in osteoclasts. Both CA II and TRACP mRNAs were detected in putative MOPC as well as multinuclear osteoclasts. The gene transcripts were mainly located in the cytoplasm of these cells. To determine whether these putative MOPC possess ER mRNA, a 637 base pair antisense ER riboprobe was used. The results indicated that MOPC which show TRACP reactivity express high levels of ER gene transcripts in their cytoplasm. In contrast, only a few multinuclear osteoclasts in the bone imprints possessed ER gene transcripts. Interestingly, the levels of ER mRNA in these multinuclear osteoclasts were very low compared with those in the putative MOPC. Treatment with RNase prior to hybridization resulted in a significant loss of signal in these cells. The results of these studies suggest that estrogen may have a direct role in modulating the recruitment of osteoclast precursor cells during osteoclastogenesis.

Osteoclasts from human giant cell tumors of bone lack estrogen receptors

Although estrogen is important in human skeletal homeostasis, the major target cell in bone is unknown. Estrogen receptors (ER) have been demonstrated in osteoblasts and bone marrow stromal cells, but their presence in osteoclasts remains controversial because completely pure preparations have not been available. We have examined expression of ER-alpha and ER-beta messenger RNA (mRNA) by RT-PCR in samples from human giant cell tumor of bone (GCT), including: whole tumor, cultured mononuclear cells, and a pure osteoclast population obtained by microisolation. Whole tumor expressed both ER-alpha and calcitonin receptor (CTR) mRNA and apparently lower levels of ER-beta mRNA. Passaged cultures of tumor mononuclear stromal cells also expressed ER-alpha and low ER-beta but not CTR mRNA. In pure preparations of microisolated osteoclasts, expression of ER-alpha or ER-beta mRNA was not detected, whereas expression of CTR mRNA was readily identified. Microisolated GCT mononuclear cells expressed ER-alpha, but no detectable CTR mRNA. Fluorescence in situ hybridization (FISH) using an ER-alpha riboprobe demonstrated strong signal in the mononuclear cells but multinucleated osteoclasts showed no detectable signal. In contrast, CTR mRNA was detected in multinucleated osteoclasts but not in stromal-like tumor cells by FISH. 17Beta-estradiol consistently showed no effect on bone resorbing activity of osteoclasts from GCT cultured on cortical bone, although calcitonin was a potent inhibitor. These findings indicate that significant expression of ER does not occur in osteoclasts derived from human GCT and suggest that estrogen effects are mediated by other cells of the bone environment.

Chronic exposure of neonatal cardiac myocytes to hydrogen peroxide enhances the expression of catalase

The adaptive response of antioxidant enzymes to oxidative stress in the heart has not been investigated. Because H2O2 is considered to play a major role in reperfusion injury to the heart, this study was undertaken to examine if H2O2 alters the expression of these enzymes in the rat neonatal myocytes. H2O2 was continuously generated by the addition of glucose oxidase to the culture medium. Both the activity and the mRNA for catalase were increased following incubation of neonatal myocytes with non-toxic concentrations of glucose oxidase. The induction of mRNA preceded the enhancement of activity, and both remained elevated after 24 h incubation. Nuclear run-on assay indicated that the transcriptional rate for catalase mRNA was increased. The same treatment did not alter the activities for total superoxide dismutase and Se-glutathione peroxidase. The results suggest that H2O2-induced expression of catalase was in part due to transcriptional activation. It further implies that the induction of catalase may play an important role in protecting hearts from ischemic/reperfusion injury.

Partial inhibition of Na+/K+-ATPase by ouabain induces the Ca2+-dependent expressions of early-response genes in cardiac myocytes

Exposure of neonatal rat cardiac myocytes to ouabain concentrations that caused partial inhibition of Na+/K+-ATPase but no loss of viability, increased c-fos and c-jun mRNAs and the transcription factor AP-1. The increased mRNAs were proportional to the extent of inhibition of Na+/K+-ATPase and the resulting rise in steady state intracellular Ca2+ concentration. The rapid and sustained increase of c-fos mRNA was shown to be due to increased transcriptional rate. Induction of c-fos by ouabain was prevented when either extracellular or intracellular Ca2+ was lowered and was attenuated by pretreatment of myocytes with a phorbol ester under conditions known to down-regulate protein kinase C. Exposure to ouabain for 24-48 h also increased total transcriptional activity and protein content of myocytes. The findings suggest that the same signal responsible for the positive inotropic action of ouabain, i.e. net influx of Ca2+ caused by partial inhibition of Na+/K+-ATPase, also initiates the rapid protein kinase C-dependent inductions of the early-response genes, the subsequent regulations of other cardiac genes by the resulting transcription factors, and stimulation of myocyte growth. Whether these hitherto unrecognized effects of cardiac glycosides are obtained in the intact heart and their relevance to the therapeutic uses of these drugs remain to be determined.

Activation of Na+/K(+)-ATPase by fatty acids, acylglycerols, and related amphiphiles: structure-activity relationship

A number of fatty acids and derivatives have been shown to activate Na+/K(+)-ATPase when ATP is suboptimal. To explore the relation of the structures of these amphiphiles to enzyme activation, the effects of varying amphiphile concentrations on the activity of the highly purified kidney Na+/K(+)-ATPase at 50 microM ATP were determined. Among fatty acids, efficacy (maximal level of activation) and potency were found to be dependent, in different ways, on chain length and unsaturation. Compared to fatty acids, the corresponding alcohols had lower efficacies. Methyl esters of fatty acids inhibited, but CoA esters and monoacyl esters of glycerol activated the enzyme. Relation between chain length and potency among CoA esters and monoacylglycerols was the same as that observed with acids. Diacylglycerols did not activate, but they antagonized the effects of the activator amphiphiles. The substantial specificities of the amphiphile effects support the hypothesis that these ligands bind to a distinct amphipathic peptide segment of the intracellular central loop of the alpha-subunit to regulate ATP binding to the enzyme. The findings also suggest that direct effects of the changing intracellular levels of fatty acids and derivatives on Na+/K(+)-ATPase should be considered as a possible mechanism for the regulation of its function in the intact cell.

Dual phenotypic expression of hepatocytes and bile ductular markers in developing and preneoplastic rat liver

This study supports the existence of a pluripotent liver stem cell population which has the potential to differentiate into hepatocytes and bile ductular cells. We compared the expression of hepatocyte-specific and bile ductular-specific markers in fetal and preneoplastic rat liver. L-pyruvate kinase (L-PK) and alpha glutathione S-transferase (GST) were used as adult hepatocyte-specific markers, while cytokeratin 19 (CK19) was used as a bile ductular-specific marker. pi GST and M2-pyruvate kinase (M2-PK), which are fetal hepatocyte-specific and expressed at high levels in the oval and duct-like cells, were also used. We characterized fetal liver derived from 13-21 days of gestation (E13-E21). pi GST was detected in the E18 hepatoblasts, which form the intrahepatic bile ducts, while CK19 was detected at E19. Some of these cells express alpha GST and L-PK from E19 to E21. Oval, duct-like and bile ductular cells in rats treated with a choline-deficient diet containing 0.07% ethionine (CDE diet) for up to 8 weeks were characterized by double immunocytochemistry. L-PK and alpha GST are absent from bile ductular cells in the normal adult liver and up to 3 weeks of CDE treatment. After 4-5 weeks on CDE treatment, the majority of bile ductular cells express L-PK, while at 6 weeks some co-express L-PK and alpha GST. There are two populations of oval cells, a major population expressing only the fetal hepatocyte markers, while a minor population expresses the fetal hepatocyte, adult hepatocyte and bile ductular markers. There are at least three different duct-like cell populations which co-express different markers and have characteristics of fetal hepatocytes at sequential stages of differentiation. One population co-expresses pi GST and M2-PK and is similar to fetal hepatocytes derived from E13-E14 fetuses. The second expresses the two fetal markers and L-PK, and this reflects characteristics of E15 hepatocytes. The third expresses pi GST, M2-PK, L-PK and alpha GST which is characteristic of E16-E19 hepatocytes. Upon withdrawal of the CDE diet, autoradiography using tritiated thymidine shows that oval and duct-like cells differentiate into hepatocytes. This study demonstrates that oval and duct-like cells express both hepatocytic and bile ductular markers, and have the capacity to differentiate into hepatocytes, characteristics similar to hepatoblasts in the developing rat liver.

Synchronous bilateral carcinoma of the ureter in association with unilateral incomplete duplication of the ureter

A case of bilateral synchronous ureteral tumors, in association with a unilateral incomplete duplication of ureter, is presented. This patient underwent right nephroureterectomy with removal of a cuff of bladder, partial resection of left ureter, and ileal loop interposition between renal pelvis and bladder. Followup showed no recurrence in the residual urinary tract 2-years postoperatively.

Antioxidant enzyme gene transcription in copper-deficient rat liver

Antioxidant enzymes, Cu/Zn- and Mn-superoxide dismutase, catalase, and glutathione peroxidase, constitute an important defense mechanism against cytotoxicity of reactive oxygen species. Copper is essential for the activity of Cu/Zn-superoxide dismutase. Oxidative stress, therefore, is expected in organs of rats fed copper-deficient diet due to reduced Cu/Zn-superoxide dismutase activity. Our previous studies have shown that the expression of antioxidant enzymes was altered in copper-deficient rat liver. The present report was undertaken to study further the transcription of these enzymes in liver nuclei of rats made copper-deficient for 4 weeks. While copper deficiency decreased the copper in liver by about 80%, it did not alter the copper content in liver nuclei. In spite of a 100% elevation in nuclear iron concentration, liver nuclei from copper-deficient rats showed normal appearance. The transcriptional rates for Cu/Zn-superoxide dismutase, glutathione peroxidase, and glyceraldehyde-3-phosphate dehydrogenase were not altered by dietary copper deprivation. In contrast, transcriptional rates for Mn-superoxide dismutase and beta-actin were increased but that for catalase was reduced in the nuclei isolated from the copper-deficient rat liver. These results suggest that oxidative stress, resulting from copper deficiency, differentially modulates the gene transcription for the antioxidant enzymes in rat liver.