Spontaneous resolution of carotid stenosis--a case for routine preoperative duplex ultrasound

Spontaneous resolution of carotid stenosis has not been previously reported in the context of preoperative duplex ultrasound scanning, although it has been described as a recognizable phenomenon in the past. We report a case in whom significant carotid stenosis was noted at the time of listing for surgery on both duplex ultrasound and MRA. On preoperative imaging there was resolution of the lesion and surgery was avoided. This case emphasises that spontaneous resolution of carotid stenosis can occur and that preoperative duplex is useful as a prelude to surgery and can prevent unwarranted intervention.

Atorvastatin inhibits calcification and enhances nitric oxide synthase production in the hypercholesterolaemic aortic valve

OBJECTIVE

To study in a rabbit model the expression of endothelial nitric oxide synthase (eNOS) in association with the development of calcification of the aortic valve, and to assess the effects of atorvastatin on eNOS expression, nitrite concentration, and aortic valve calcification.

METHODS

Rabbits (n = 48) were treated for three months: 16, forming a control group, were fed a normal diet; 16 were fed a 0.5% (wt/wt) high cholesterol diet; and 16 were fed a 0.5% (wt/wt) cholesterol diet plus atorvastatin (2.5 mg/kg/day). The aortic valves were examined with eNOS immunostains and western blotting. Cholesterol and high sensitivity C reactive protein (hsCRP) concentrations were determined by standard assays. Serum nitrite concentrations were measured with a nitric oxide analyser. eNOS was localised by electron microscopy and immunogold labelling. Calcification in the aortic valve was evaluated by micro-computed tomography (CT).

RESULTS

Cholesterol, hsCRP, and aortic valve calcification were increased in the cholesterol fed compared with control animals. Atorvastatin inhibited calcification in the aortic valve as assessed by micro-CT. eNOS protein concentrations were unchanged in the control and cholesterol groups but increased in the atorvastatin treated group. Serum nitrite concentrations were decreased in the hypercholesterolaemic animals and increased in the group treated with atorvastatin.

CONCLUSION

These data provide evidence that chronic experimental hypercholesterolaemia produces bone mineralisation in the aortic valve, which is inhibited by atorvastatin.

Medical students' behaviour, attitudes and knowledge of sleep medicine

INTRODUCTION

A seminar on sleep disorders was recently introduced for third, fourth and final year medical students rotating through the psychiatry posting in the Institute of Mental Health. This survey was conducted to assess the attitudes as well as knowledge of medical students towards sleep medicine.

METHODS

Verbal consent was taken from the students who were willing to take part in the survey. The MED Sleep Survey, which is an inventory to assess behavior, attitudes and knowledge about sleep, was used to assess the same in the students.

RESULTS

A total of 240 medical students completed the survey. There were 149 male and 91 female medical students. In terms of their basic sleep knowledge, 46.7 percent scored between 1 and 10 points, 51.7 percent scored between 11 and 20 points, and 1.7 percent scored between 21 and 30 points. There was no significant difference between the different groups in their scores on basic sleep knowledge.

CONCLUSION

Most of the medical students scored between 1 and 20 points on basic sleep knowledge items in part III of the survey. Of these, almost one-half had scores between 1 and 10 points. Education is clearly important, and the introduction of the teaching programme on sleep medicine is timely and necessary.

Magnetic resonance angiography in potential live renal donors: a joint radiological and surgical evaluation

AIM

To assess the impact of a joint surgical and radiological audit on the accuracy of contrast-enhanced magnetic resonance angiography (MRA) reports in the evaluation of potential renal donors.

MATERIALS AND METHODS

We analysed the records of live renal donors who underwent gadolinium-enhanced MRA as part of the pre-operative evaluation to assess renal vasculature between August 1999 and July 2002 when feedback from surgical findings to radiology had been available. In cases of discrepancy between MRA reports and surgical findings, studies were retrieved from the magnetic resonance imaging (MRI) workstation and subjected to detailed joint clinical and radiological review. Scan quality was assessed and sources of discrepancy were identified.

RESULTS

There were 45 donors, 23 men and 22 women with a mean age of 41 years. Reported MRA findings were fully confirmed at surgery in 38 of 45 cases. These images were not analysed further. In seven donors the findings at surgery were discrepant with the radiological reports: there were four cases of "missed" early branches and three cases of "missed" accessory arteries. In the first year of the audit there were four discrepant cases out of 18 (22%), all of which were radiological reporting errors. The number of discrepant cases in the second year was two out of 19 cases (11%). Neither of these was a radiological reporting error. There was one "missed" early renal artery branch in the third year of audit, which was identified on MRA review.

CONCLUSION

The study highlights the importance of detecting and clearly reporting not only accessory renal arteries, but also early renal arterial branches in the pre-operative evaluation of renal donors. The accuracy of pre-operative MRA in potential renal donors is high, but radiological reporting of MRA examinations is improved through careful clinical feedback, audit and interdisciplinary co-operation.

Mutational analysis of the Mycobacterium tuberculosis Rv1625c adenylyl cyclase: residues that confer nucleotide specificity contribute to dimerization

The mycobacterial Rv1625c gene product is an adenylyl cyclase with sequence similarity to the mammalian enzymes. The catalytic domain of the enzyme forms a homodimer and residues specifying adenosine triphosphate (ATP) specificity lie at the dimer interface. Mutation of these residues to those present in guanylyl cyclases failed to convert the enzyme to a guanylyl cyclase, but dramatically reduced its adenylyl cyclase activity and altered its oligomeric state. Computational modeling revealed subtle differences in the dimer interface that could explain the biochemical data, suggesting that the structural and catalytic features of this homodimeric adenylyl cyclase are in contrast to those of the heterodimeric mammalian enzymes.

Further characterization of human fetal osteoblastic hFOB 1.19 and hFOB/ER alpha cells: bone formation in vivo and karyotype analysis using multicolor fluorescent in situ hybridization

We have previously generated an immortalized human fetal osteoblastic cell line (hFOB) using stably transfected temperature sensitive SV40 T-antigen (Harris et al. [1995a] J. Bone. Miner. Res. 10:178-1860). To characterize these cells for phenotypic/genotypic attributes desired for a good cell model system, we performed karyotype analysis by multicolor fluorescent in situ hybridization (M-FISH), their ability to form bone in vivo without developing cell transformation, and finally their ability to form extracellular matrix formation in vitro. The karyotype analysis of hFOB cells revealed structural or numeric anomalies involving 1-2 chromosomes. In contrast, the human osteosarcoma MG63 cells displayed multiple, and often complex, numeric, and structural abnormalities. Subcutaneous injection of hFOB cells in the presence of Matrigel into nude mice resulted in bone formation after 2-3 weeks. Electron microscopic analysis of the extracellular matrix deposited by hFOB cells in culture revealed a parallel array of lightly banded fibrils typical of the fibrillar collagens such as type I and III. These results demonstrate that the hFOB cell line has minimal chromosome abnormalities, exhibit the matrix synthetic properties of differentiated osteoblasts, and are immortalized but non-transformed cell line. These hFOB cells thus appear to be an excellent model system for the study of osteoblast biology in vitro.

Mutual antagonism of estrogen receptors alpha and beta and their preferred interactions with steroid receptor coactivators in human osteoblastic cell lines

Estrogen is a major sex steroid that affects the growth, maintenance, and homeostasis of the skeleton. Two isoforms of the estrogen receptor (ERalpha and ERbeta) mediate the transcriptional effects of estrogen. Although both isoforms of ER are present and functional in some human osteoblast (OB) cell lines, there is minimal information on the differential regulation of transcription by ERalpha and ERbeta homo- or heterodimers. This report demonstrates that ERalpha and ERbeta coexpression decreases the transcriptional capacity (relative to each ER isoform alone) on an estrogen response element-dependent reporter gene in OBs but not in other non-osteoblastic cell lines. These data suggest that ERalpha and ERbeta coexpression can differentially influence the degree of transcriptional activation in certain cell types. Interestingly, the overexpression of the steroid hormone receptor coactivator-1 (SRC1) resulted in preferential transcriptional enhancement by ERbeta as well as coexpressed ERalpha and ERbeta, whereas SRC2 overexpression appeared to preferentially enhance ERalpha transactivation. SRC3 overexpression failed to enhance estrogen-dependent transcription of any ER combination in OBs. Similar overexpression experiments in COS7 cells exhibited preferential enhancement of ERalpha function with all SRCs, including SRC3. Our data also demonstrated that SRC3 mRNA is reduced in osteoblastic cells, suggesting that SRC3 may have only a minor role in these cells. These data suggest that the transactivation capacity of various ER isoforms is both SRC species and cell type dependent.

Cell-volume changes and ion conductances in amphibian gallbladder epithelium

Cell-volume regulation after hyposmotic swelling is common in transporting epithelial cells. Acute regulatory volume decrease is mediated in several cell types by loss of K(+) and Cl(-) via channels either activated by the swelling phenomenon or active in the cell membrane prior to swelling. In the last two decades, it has become clear that many features of cell-volume regulation mediated by ion fluxes vary considerably among cell types. In some instances, the ion channel activation, although demonstrable, is insufficient to account, on the basis of ion fluxes, for the measured cell volume changes. Here we review the case of a salt-transporting epithelium in which hyposmotic cell swelling activates plasma membrane K(+) channels, but at the same time inhibits Cl(-) channels, thus preventing an acute volume-regulatory response. The sequence of events following cell swelling appears to be as follows: K(+) channels are activated by membrane stretch, the cell membrane hyperpolarizes (the voltage moves closer to the K(+) equilibrium potential) and this hyperpolarization reduces the Cl(-) conductance, likely by a reduction in open probability of voltage-sensitive Cl(-) channels. The significance of this phenomenon may be related to the preservation of intracellular Cl(-) rather than cell volume, or to a physiological 'need' to prevent shrinkage of cells stimulated by hormones or other mediators.

Bisphosphonates directly regulate cell proliferation, differentiation, and gene expression in human osteoblasts

Bisphosphonates are widely used clinically to treat bone diseases in which bone resorption is in excess. However, the mechanism of bisphosphonate action on bone is not fully understood. Studies of direct action of bisphosphonates on bone have been limited mainly to their effects on bone-resorbing osteoclast cells, with implications that some activity may be mediated indirectly through paracrine factors produced by the bone-forming osteoblast cells. Little is known about the direct effects of bisphosphonates on osteoblasts. In this report, the direct actions of several bisphosphonates on cell proliferation, gene expression, and bone formation by cultured human fetal osteoblasts were examined. Osteoblast cell proliferation was decreased, and cytodifferentiation was increased in a dose-dependent manner in cultures treated with the bisphosphonate pamidronate. In addition, pamidronate treatment increased total cellular protein, alkaline phosphatase activity, and type I collagen secretion in osteoblasts. Consistent with the above-mentioned findings, the rate of bone formation was also increased in osteoblasts cultured with pamidronate. The actions of two other bisphosphonates, the weak-acting etidronate and the potent new analogue zoledronate, were also compared with the action of pamidronate on proliferation of immortalized human fetal osteoblast (hFOB) cells and rate of bone formation. Pamidronate and zoledronate decreased hFOB cell proliferation with equal potency, whereas etidronate decreased proliferation only at much higher concentrations. Studies comparing EDTA and etidronate indicate that etidronate may act indirectly on the hFOB cells by reducing free divalent ion concentrations, whereas pamidronate and zoledronate appear to act on the hFOB cells by a direct action. Both pamidronate and zoledronate increase hFOB cell bone formation, whereas no increase is observed with etidronate and EDTA. Taken together, these observations strongly suggest that treatment with pamidronate or zoledronate enhances the differentiation and bone-forming activities of osteoblasts.

Overexpression of a nuclear protein, TIEG, mimics transforming growth factor-beta action in human osteoblast cells

Although transforming growth factor-beta (TGF-beta) is a growth factor with many known regulatory activities in many different cell types, its intracellular signaling pathway is still not fully understood. A TGF-beta-inducible early gene (TIEG) was discovered and shown by this laboratory to be a 3-zinc finger transcription factor family member; its expression is rapidly induced in cells treated with TGF-beta. To ascertain whether TIEG plays a major role in the TGF-beta pathway, human osteosarcoma MG-63 cells were stably transfected either with an expression vector containing a TIEG cDNA or with the vector alone. Clones that contain only the vector express normal levels of TIEG mRNA and protein and display the same patterns of gene expression and levels of cell proliferation as the nontransfected, non-TGF-beta-treated parental cells. However, transfected cells that overexpress TIEG mRNA and protein (TIEG-6 and TIEG-7) display changes that mimic those of MG-63 cells treated with TGF-beta, i.e. increased alkaline phosphatase activity, decreased levels of osteocalcin mRNA and protein, and decreased cell proliferation. The degree of these changes correlated with the level of TIEG expressed in the cell lines. TGF-beta treatment of the overexpressed cells showed no added effects. These findings and other published reports support a primary role of TIEG as a transcription factor in the TGF-beta signaling pathway.

Cytokine-specific induction of the TGF-beta inducible early gene (TIEG): regulation by specific members of the TGF-beta family

Select members of the TGF-beta family of cytokines play key regulatory roles in skeletal development, structure, and turnover. This laboratory has previously reported that TGF-beta treatment of immortalized normal human fetal osteoblast (hFOB) cells results in the rapid induction of the mRNA levels of a TGF-beta inducible early gene (TIEG) followed by changes in cell proliferation and bone matrix protein production. Previous studies have also shown that nonmembers of the TGF-beta superfamily showed little or no induction of TIEG mRNA. This article further addresses the cytokine specificity of this TIEG induction by examining whether activin and select bone morphogenetic proteins, (BMP-2, BMP-4, and BMP-6), which are representative of different subfamilies of this superfamily, also induce the expression of TIEG in hFOB cells. However, TGF-beta remained the most potent of these cytokines, inducing TIEG mRNA steady-state levels at 0.1 ng/ml, with a maximum induction of 24-fold at 2.0 ng/ml. The BMP-2 (16-fold), BMP-4 (4-fold), and activin (1-3-fold) also induced TIEG mRNA levels, but at reduced degrees compared to TGF-beta (24-fold), and only at much higher cytokine concentrations, e.g., 50-100 ng/ml, compared to 2 ng/ml for TGF-beta. BMP-6 showed no effect on TIEG mRNA levels. The TIEG protein levels generally correlated with the mRNA steady-state levels. As with TGF-beta, BMP-2 treatment of hFOB cells was shown by confocal microscopy to induce a rapid translocation of the TIEG protein to the nucleus. In summary, the relative potencies of these TGF-beta family members to induce TIEG expression generally follows the general osteoinductive capacity of these cytokines, with TGF-beta >>> BMP-2 > BMP-4 > activin >> BMP-6.

Interactions of the nuclear matrix-associated steroid receptor binding factor with its DNA binding element in the c-myc gene promoter

Steroid receptor binding factor (RBF) was originally isolated from avian oviduct nuclear matrix. When bound to avian genomic DNA, RBF generates saturable high-affinity binding sites for the avian progesterone receptor (PR). Recent studies have shown that RBF binds to a 54 bp element in the 5'-flanking region of the progesterone-regulated avian c-myc gene, and nuclear matrix-like attachment sites flank the RBF element [Lauber et al. (1997) J. Biol. Chem. 272, 24657-24665]. In this paper, electrophoretic mobility shift assays (EMSAs) and S1 nuclease treatment are used to demonstrate that the RBF-maltose binding protei (MBP) fusion protein binds to single-stranded DNA of its element. Only the N-terminal domain of RBF binds the RBF DNA element as demonstrated by southwestern blot analyses, and by competition EMSAs between RBF-MBP and the N-terminal domain. Mass spectrometric analysis of the C-terminal domain of RBF demonstrates its potential to form noncovalent protein-protein interactions via a potential leucine-isoleucine zipperlike structure, suggesting a homo- and/or possible heterodimer structure in solution. These data support that the nuclear matrix binding site (acceptor site) for PR in the c-myc gene promoter is composed of RBF dimers bound to a specific single-stranded DNA element. The dimers of RBF are generated by C-terminal leucine zipper and the DNA binding occurs at the N-terminal parallel beta-sheet DNA binding motif. This complex is flanked by nuclear matrix attachment sites.

Molecular and cellular mechanisms of estrogen action on the skeleton

The many recent and exciting advances that have taken place in the field of estrogen action on the skeleton are the subjects of this review. Leading these new developments is the discovery of alternative estrogen receptors that exhibit differential mechanisms of transcriptional control of estrogen-responsive promoters, thereby broadening both the ranges of possible target cells and their responses. More potentially important genes under estrogenic control have been identified in vitro, and the skeletal phenotypes caused by disruption of estrogen signaling due to mutations in humans and mice have been described. Lastly, clinical studies in humans have revealed a greater appreciation for the importance of estrogen in bone mass maintenance in both sexes. J. Cell. Biochem. Suppls. 32/33:123-132, 1999.

Religious--sociocultural psychotherapy in patients with anxiety and depression

OBJECTIVE

To show the effectiveness of incorporating religious-sociocultural components in the management of patients with generalised anxiety disorders and major depression who have strong religious and cultural backgrounds as compared with a normal psychotherapeutic approach.

METHODS

One hundred and three cases of anxiety and 100 cases of depression with strong religious and cultural backgrounds were randomly assigned to the study or control groups. Both groups received standard treatment for their respective illnesses. The study group was given additional religious-sociocultural psychotherapy. They were followed for 6 months and were assessed in a double-blind fashion using the Hamilton Anxiety Rating Scale or the Hamilton Depression Rating Scale.

RESULTS

Patients receiving additional religious-sociocultural psychotherapy responded significantly faster than those who received standard treatment. However, the difference became non-significant at the end of 6 months.

CONCLUSIONS

Incorporating a religious and sociocultural component in the treatment program rapidly improved anxiety and depressive symptoms in patients with strong religious and cultural backgrounds. The present study demonstrates a need for more sensitivity to religious-sociocultural issues in the field of mental health.

TGFbeta-inducible early gene (TIEG) also codes for early growth response alpha (EGRalpha): evidence of multiple transcripts from alternate promoters

TGFbeta-inducible early gene (TIEG) and early growth response alpha (EGRalpha) are putative transcription factors based on homology to known zinc finger proteins SP1, EGR1, BTEB, and Wilm tumor. Here we report that TIEG and EGRalpha are expressed from alternative promoters of the same gene. The TIEG/EGRalpha gene spans 8 kb and contains five exons. Use of alternative first exons results in TIEG having 12 unique amino acids on its N-terminus. Computer analysis of the 5' upstream regions of either TIEG (exon 1a) or EGRalpha (exon 1b) does not identify a TATA box or initiator sequencebut shows consensus sequence similarities to binding sites for several transcription factors including SP1,JunB, and aromatic hydrocarbon/receptor-ligand complexes. Analysis of constructs containing 5'-flanking regions show that both the TIEG and the EGRalpha promoters have significant activity in human fetal osteoblast cells. Northern analysis of mRNA from various human tissues and several cell lines reveals that TIEG is the predominant transcript produced and regulated by growth factors from the TIEG/EGRalpha gene.

Estrogen regulation of a transforming growth factor-beta inducible early gene that inhibits deoxyribonucleic acid synthesis in human osteoblasts

This laboratory reported the identification and characterization of a unique three zinc finger, transcription factor-like, transforming growth factor-beta inducible early gene (TIEG) (see Ref. 35). TIEG expression has been shown to be tissue- and cell type specific, enhanced by specific growth factors, and to decrease with advancing stages of breast cancer. Recent studies involving TIEG overexpression in pancreatic carcinoma cells indicate that TIEG expression inhibits DNA synthesis, similar to a tumor suppressor-like gene, and plays a role in apoptosis (see Ref. 37). This paper describes the rapid, but transient, induction of TIEG steady-state messenger RNA (mRNA) levels by 17beta-estradiol (E2) in estrogen receptor (ER)-positive, human fetal osteoblastic (hFOB/ER) cells. This rapid induction is shown to be ER- and steroid dose-dependent but protein synthesis independent. An antagonism between E2 and PTH, which occurs in skeletal metabolism, is shown to concur rapidly with TIEG mRNA expression. Scanning confocal microscopy (using polarized, laser-based immunofluorescence) shows that TIEG protein is localized in the nucleus of hFOB/ER cells, with the levels rapidly increasing after E2 treatment. The rapid E2-induced increase in TIEG expression is followed by an E2-induced inhibition of DNA synthesis in the hFOB/ER cells. Antiestrogens block not only the induction of TIEG mRNA levels but also the inhibition of cell proliferation. Lastly, hFOB cells, stably transfected with a TIEG expression vector, display markedly reduced DNA synthesis/cell proliferation, compared with nontransfected cells. These results support the finding that TIEG is an early responding regulatory gene for E2 in human osteoblast cells that inhibits DNA synthesis. It is speculated that TIEG may play a role in the signaling pathway for E2 in inhibiting cell proliferation.

Tissue, cell type, and breast cancer stage-specific expression of a TGF-beta inducible early transcription factor gene

This laboratory has previously identified a novel TGF-beta inducible early gene (TIEG) in human osteoblasts [Subramaniam et al. (1995): Nucleic Acids Res 23:4907-4912]. Using TIEG specific polyclonal antibody and immunoprecipitation methods in normal human fetal osteoblast cells (hFOB cells), we have now demonstrated that TIEG encodes a 72-kDa protein whose levels are transiently increased at as early as 2 h of TGF-beta treatment. Polarized confocal microscopic analysis of hFOB cells shows a nuclear localized TIEG protein in untreated cells under the conditions described under Methods. Interestingly, the levels of TIEG protein in the nuclei increase when the cells are treated with TGF-beta 1 for 2 h. In contrast, similar analyses of untreated human keratinocytes show a cytoplasmic localized TIEG protein that appears to be translocated to the nucleus after H2O2 treatment. Additional immunohistochemical studies have demonstrated that TIEG protein is expressed in epithelial cells of the placenta, breast, and pancreas, as well as in osteoblast cells of bone and selected other cells of the bone marrow and cerebellum with some cells showing a cytoplasmic localization and others a nuclear localization. All cells of the kidney display negative staining for this protein. Interestingly, a stage specific expression of TIEG protein is found in a dozen breast cancer biopsies, using immunohistochemistry. The cells in normal breast epithelium displays a high expression of TIEG protein, those in the in situ carcinoma display less than one-half of the levels, and those in the invasive carcinoma show a complete absence of the TIEG protein. TIEG has been localized to chromosome 8q22.2 locus, the same locus as the genes involved in osteopetrosis and acute myeloid leukemia and close to the c-myc gene locus and a locus of high polymorphism in cancer biopsies. The correlation between the levels of TIEG protein and the stage of breast cancer, its prime location in human chromosome 8q22.2, and past studies with pancreatic carcinoma, suggests that TIEG may play a role in tumor suppressor gene activities, apoptosis, or some other regulatory function of cell cycle regulation.