Anesthesia for a Patient with Undiagnosed Myotonic Dystrophy

ABSTRACT

Myotonic dystrophy (DM) is an autosomal dominant genetic disorder characterized by progressively worsening loss of muscle mass and weakness. Anesthesiologists face challenges in managing these patients due to risks such as prolonged intubation and delayed recovery associated with anesthesia in such conditions. We report a case of a 40-year-old male patient undergoing open total gastrectomy under general anesthesia. After the surgery, we administered sugammadex to reverse neuromuscular blockade and confirmed the patient's spontaneous breathing. We then proceeded to extubate the patient. However, the patient experienced complications such as apnea, desaturation, and mental changes. The patient was re-intubated and transferred to the intensive care unit for ventilator support. He was diagnosed with DM by genetic test later. Poor preoperative assessment or undiagnosed DM in surgical patients can lead to severe complications. Thus, it is important to carefully check preoperative laboratory results, patient history, and physical findings.

Midline catheters in the operating room

Backgrounds

Among various vascular access devices, midline catheters (MCs) are commonly used in emergency departments, but rarely in operating rooms.

Aims

To evaluate the feasibility and safety of MCs in the operating room.

Materials and Methods

This was a retrospective study. The medical records of patients who underwent MC placement in the operating room from October 2020 to July 2022 were reviewed. The rates of successful catheter insertion as well as major and minor complications were assessed.

Results

Successful catheter insertions were achieved in 149 of 161 patients (92.5%). The median dwell time of midlines was eight days (IQR: 6-10 days). A major or minor complication occurred in 6.7% of the midlines. The rates of major complications of occlusion, upper extremity deep vein thrombosis (DVT), and catheter-related bloodstream infection were 1.3%, 0.7%, and 0%, respectively.

Conclusions

Placement of MCs in the operating room was feasible and safe. Also, the procedure provides an acceptable alternative for replacing central line catheters and peripherally inserted central catheters.

Risk Factors Affecting Complications of Access Site in Vascular Intervention through Common Femoral Artery

Backgrounds

Traditionally, vascular interventions have been performed through the femoral artery.

Aims

The purpose of this study was to evaluate risk factors affecting access-site complications in patients with hepatocellular carcinoma or peripheral arterial disease in lower extremity who underwent vascular intervention by accessing the common femoral artery (CFA).

Patients and Methods

From December 2015 to November 2018, 287 patients underwent transarterial chemoembolization (TACE) or peripheral vascular intervention with ultrasound (US)-guided CFA access. Standard 18-gauge (G) access was used in 127 patients and Micropuncture® 21-G needles in 160 patients. Most access sites were managed with vascular closure devices and several were managed with manual compression. Within 24 hours after the procedure, all patients underwent US to evaluate the puncture site.

Results

Access-site complications occurred in 55 of 287 patients: 34 hematomas (11.9%), 20 pseudoaneurysms (7.0%), and 1 dissection (0.4%). In the crude model, risk factors related to access-site complications were the usage of 18-G needles (OR, 2.18; 95% CI, 1.17-4.07; P = 0.014), smoking (OR, 2.23; 95% CI, 1.16-4.27; P = 0.016), and approach route (OR, 3.23; 95% CI, 1.33-7.82; P = 0.009). Needle size (OR, 2.13; 95% CI, 1.10-4.12; P = 0.025) was the only factor associated with access-site complications in the adjusted model.

Conclusion

Needle profile was the only factor associated with access-site complications in this study. Therefore, a needle with a smaller profile than an 18-G needle will reduce the incidence of complications at the access site.

Haplotype structure and copy number polymorphism of the beta-defensin 7 genes in diverse chicken breeds

Beta-defensins is a family of avian peptides related to the innate immune system. Copy number variation was recently reported for the avian beta-defensin 7 gene (AvBD7) between the highly inbred Leghorn and Fayoumi lines. Here, we examined copy number variants in 35 different chicken breeds and found that 31 of them have at least the same representation of the duplicated AvBD7 allele. We also found haplotypes upstream of the AvBD6 regions that are strongly linked to the AvBD7 duplication. We observed a strong linkage disequilibrium spanning of the upstream region of the AvBD6 gene, with two SNPs being flanking markers to detect duplication of the AvBD7.

Genetic variation and gene conversions within the bovine NK-lysin gene family

In contrast to a single copy of the NK-lysin gene in humans and many other mammals, we previously identified a family of four expressed NK-lysin genes arising by tandem duplications on cattle chromosome 11. Here, we report two genetic variants in the bovine NK-lysin complex with potential importance in the bovine innate immune system. The first one is a 9-bp deletion causing a three-amino-acid deletion in the pro-region of the NK1 gene product. The second is a deletion of NK2B in some Holstein cattle, resulting in copy number variation that is in disequilibrium with a SNP from the bovine 770K HD SNP array. We also show evidence for gene conversions within the three new NK2 genes, which at least partially accounts for their high degree of sequence identity.

Biallelic expression of the L-arginine:glycine amidinotransferase gene with different methylation status between male and female primordial germ cells in chickens

The basic functions of DNA methylation include in gene silencing by methylation of specific gene promoters, defense of the host genome from retrovirus, and transcriptional suppression of transgenes. In addition, genomic imprinting, by which certain genes are expressed in a parent-of-origin-specific manner, has been observed in a wide range of plants and animals and has been associated with differential methylation. However, imprinting phenomena of DNA methylation effects have not been revealed in chickens. To analyze whether genomic imprinting occurs in chickens, methyl-DNA immunoprecipitation array analysis was applied across the entire genome of germ cells in early chick embryos. A differentially methylated region (DMR) was detected in the eighth intron of the l-arginine:glycine amidinotransferase (GATM) gene. When the DMR in GATM was analyzed by bisulfite sequencing, the methylation in male primordial germ cells (PGC) of 6-d-old embryos was higher than that in female PGC (57.5 vs. 35.0%). At 8 d, the DMR methylation of GATM in male PGC was 3.7-fold higher than that in female PGC (65.0 vs. 17.5%). Subsequently, to investigate mono- or biallelic expression of the GATM gene during embryo development, we found 2 indel sequences (GTTTAATGC and CAAAAA) within the GATM 3'-untranslated region in Korean Oge (KO) and White Leghorn (WL) chickens. When individual WL and KO chickens were genotyped for indel sequences, 3 allele combinations (homozygous insertion, homozygous deletion, and heterozygotes) were detected in both breeds using a gel shift assay and high-resolution melt assay. The deletion allele was predominant in KO, whereas the insertion allele was predominant in WL. Heterozygous animals were evenly distributed in both breeds (P < 0.01). Despite the different methylation status between male and female PGC, the GATM gene conclusively displayed biallelic expression in PGC as well as somatic embryonic, extraembryonic, and adult chicken tissues.

Transient expression of iron transport proteins in the capillary of the developing rat brain

Iron is essential for normal brain function and its uptake in the developing rat brain peaks during the first two weeks after birth, prior to the formation of the blood–brain barrier (BBB). The first step of iron transport from the blood to the brain is transferrin receptor (TfR)-mediated endocytosis in the capillary endothelial cells. However, the subsequent step from the endothelium into interstitium has not been fully described. The goal of this study was to examine the expression of iron transport proteins by immunodetection and RT–PCR in the developing rat brain. Tf and TfR are transiently expressed in perivascular NG2+ cells of the capillary wall during the early postnatal weeks in the rat brain. However, MTP-1 and hephaestin were expressed in endothelial cells, but not in the NG2+ perivascular cells. Immunoblot analysis for these iron transfer proteins in the developing brain generally confirmed the immunochemical findings. Furthermore, the expression of Tf and TfR in the blood vessels precedes its expression in oligodendrocytes, the main iron-storing cells in the vertebrate brain. RT–PCR analysis for the primary culture of endothelial cells and pericytes revealed that Tf and TfR were highly expressed in the pericytes while MTP-1 and hephaestin were expressed in the endothelial cells. The specific expression of Tf and TfR in brain perivascular cells and MTP-1 and hephaestin in endothelial cells suggest the possibility that trafficking of elemental iron through perivascular cells may be instrumental in the distribution of iron in the developing central nervous system.

LH induces orphan nuclear receptor Nur77 gene expression in testicular Leydig cells

The orphan nuclear receptor Nur77 (NR4A1) is a member of the nuclear receptor superfamily and plays an important role in the regulation of genes involved in steroidogenesis and cell death. Northern blot analysis revealed that the expression of Nur77 mRNA was increased after puberty in mouse testis, and hCG treatment of peripubertal animals induced this gene expression in the testis. Moreover, LH treatment induced a transient increase in Nur77 mRNA, and this induction was LH dose dependent in mouse Leydig tumor cell line, K28. Western blot analysis showed that LH transiently induced Nur77 protein. The protein kinase inhibitor H-89, bisindolymaleimide I, and wortmannin strongly inhibited this inductive effect of LH on Nur77 gene expression. Transient transfection assay demonstrated that LH significantly increased the Nur77 promoter-driven luciferase reporter activity in a dose-dependent manner, and LH also increased the activity of a luciferase reporter gene driven by a promoter containing multi copies of a Nur77-responsive element. Moreover, EMSA showed that Nur77 DNA-binding activity was increased in response to LH. Finally, overexpression of dominant negative Nur77 reduced LH-mediated progesterone biosynthesis. Taken together, these results demonstrate that LH induces Nur77 gene expression, and Nur77 may play an important role in the LH-mediated steroidogenesis in Leydig cells.

Hepatitis B virus X protein induced expression of the Nur77 gene

Hepatitis B virus (HBV) X protein (HBx) plays an essential role in development of HBV-associated hepatocellular carcinoma (HCC). Recently, we reported that HBx induces Fas Ligand (FasL) expression, which may help HCC cells to evade host-immune surveillance. The aim of this study was to investigate the role of HBx in expression of Nur77, an orphan nuclear receptor implicated in the upregulation of FasL. When Chang X-34 expressing HBx under the control of a doxycycline-inducible promoter was examined, induction of Nur77 was observed following HBx expression. Blocking of Nur77 function by introduction of an antisense or a dominant negative mutant Nur77 significantly inhibited the induction of FasL, indicating that Nur77 plays critical roles in FasL expression. Further, a high-level expression of transcripts and DNA binding of Nur77 were observed in the HBV-integrated cell lines established from HCC patients that express HBx. These results suggested that Nur77 may contribute to leading the HBx-induced Fas/FasL signaling pathway which eliminates invading Fas-expressing lymphocytes.

Retinoic acid and its receptors repress the expression and transactivation functions of Nur77: a possible mechanism for the inhibition of apoptosis by retinoic acid

Nur77 (NGFI-B) is an orphan nuclear receptor that has been implicated in activation-induced T-cell apoptosis. Retinoids, potent immune modulators, were shown to inhibit the activation-induced apoptosis of immature thymocytes and T-cell hybridomas. To illustrate the mechanism of the inhibition, we examined the effects of retinoic acid (RA) on the expression and transactivation functions of Nur77 in the human peripheral blood mononuclear cells and the human T-cell leukemia, Jurkat. All-trans-RA remarkably repressed the DNA binding and transcriptional induction of Nur77. Among the two potential trans-acting factors that activate Nur77 gene promoter, i.e., AP-1 and related serum response factor (RSRF), all-trans-RA repressed DNA binding and reporter gene activity of AP-1 but not that of RSRF, suggesting that the inhibition may be mediated through AP-1. We also demonstrated a posttranscriptional regulation of Nur77 function by retinoid receptors by showing that transactivation activity of Nur77 was significantly inhibited by cotransfection of RARalpha or RXRalpha. Nur77 bound RARalpha or RXRalpha in both yeast and mammalian two-hybrid tests, suggesting that direct protein-protein interaction between these receptors may mediate the inhibition. Taken all together, we demonstrated that RA repressed Nur77 function through multiple mechanisms that may provide the basis for RA inhibition on the apoptosis of activated T-lymphocytes.

Activation of NF-kappaB determines the sensitivity of human colon cancer cells to TNFalpha-induced apoptosis

Tumor necrosis factor alpha (TNFalpha) generates a potent cytotoxic effect, however many cancer cells are resistant to TNFalpha-mediated killing and the cause of the differential sensitivity remains to be elucidated. In this study, we demonstrated that TNFalpha induced cell death in four different human colon cancer cell lines. The degree of cytotoxic effect was different in each cell line, in that HCT-15 was relatively sensitive, while DLD-1, HT-29 and WiDr were relatively resistant. TNFalpha induced apoptotic changes such as morphological changes, DNA fragmentation and activation of caspase-3 in HCT-15, but to a lesser degree in the others. Transcriptional expression of TNFR1(p55), as well as that of FLICE, Fas, FADD, DR3, FAF, TRADD, and RIP was similar in these cell lines, indicating that the susceptibility to TNFalpha-induced apoptosis may not be determined by the constitutive expression level of these factors. Interestingly, the cytotoxic effect of TNFalpha was well correlated with the DNA binding activity of NF-kappaB in the colon cancer cell lines. Further, the overexpression of a non-phosphorylated mutant form of IkappaBalpha enhanced the cytotoxicity of TNFalpha in the resistant cell line, DLD-1, indicating that NF-kappaB activity may determine the sensitivity of colon cancer cells to TNFalpha-induced apoptosis. Thus, our results indicate that modulation of NF-kappaB activity may provide a useful tool to sensitize colon cancer cells to TNFalpha treatment.

Differential effects of retinoic acid on growth and apoptosis in human colon cancer cell lines associated with the induction of retinoic acid receptor beta

Retinoids are well known as potential chemopreventive and chemotherapeutic agents against a variety of human cancers. Here, we report that retinoic acid (RA) induced differential growth inhibition in human colon cancer cell lines: while DLD-1, HT-29, and WiDr were relatively resistant, HCT-15 and Colo201 were relatively sensitive. All-trans-retinoic acid caused morphological and biochemical changes such as membrane shrinkage, chromatin condensation, and DNA cleavage, which are typical features of cells undergoing apoptosis in sensitive cell lines. Although retinoic acid receptor (RAR)alpha, beta, gamma and retinoid X receptor alpha were expressed in all cell lines examined, a significant induction of RARbeta by all-trans-RA was observed only in sensitive cell lines, suggesting important roles of RARbeta in RA sensitivity. When a vector containing the RARbeta gene was introduced into a relatively resistant cell line, DLD-1, the cells acquired RA sensitivity. Further, we found that the RARbeta transfectants of DLD-1 expressed an enhanced level of c-Myc and Bax proteins, which may result in the increased susceptibility of the cells to all-trans-RA-induced apoptosis. In summary, our data demonstrated that RA induced growth inhibition and apoptosis in human colon cancer cells and that the induction of RAR3 may mediate the retinoid action.

Apoptosis in human hepatoma cell lines by chemotherapeutic drugs via Fas-dependent and Fas-independent pathways

Many chemotherapeutic drugs have been found to exert their mode of action via induction of apoptosis in cancer cells. The mechanisms involved in this process are not clear. Recent studies have shown that the Fas/Fas ligand (FasL) system is a key factor controlling apoptotic cell death. In the present study, the involvement of Fas in chemotherapeutic drug-induced apoptosis in hepatoma cell lines was investigated. Five different human hepatoma cell lines, Hep G2, Hep G2.2.15, Hep 3B, SK-Hep-1, and PLC/PRF/5, were used. It was found that they expressed different levels of Fas. However, all five cell lines were susceptible to apoptosis when treated with chemotherapeutic drugs such as 5-fluorouracil (5-FU) or cisplatin. In Hep G2 that constitutively expressed Fas, 5-FU or cisplatin treatment caused an increase in the expression of Fas before the formation of oligonucleosomal DNA fragments, a typical feature of apoptosis. However, in Hep 3B, where Fas is undetectable, apoptosis could also be induced by 5-FU or cisplatin without induction of Fas. The agonistic anti-Fas antibody (CH-11) was capable of inducing apoptosis by itself and promoted drug-induced apoptosis in Hep G2 but not in Hep 3B. The antagonistic anti-Fas antibody (ZB4) inhibited drug-induced apoptosis in Hep G2. Our results suggest that apoptosis can be induced in hepatoma cell lines via both Fas-dependent and Fas-independent pathways.

Differential modulation of transcriptional activity of oestrogen receptors by direct protein-protein interactions with retinoid receptors

Control of oestradiol-responsive gene regulation by oestrogen receptors (ERs) may involve complex cross-talk with retinoic acid receptors (RARs) and retinoid X receptors (RXRs). Recently, we have shown that ERalpha directly interacts with RARalpha and RXRalpha through their ligand binding domains (LBDs). In the present work, we extend these results by showing that ERbeta binds similarly to RARalpha and RXRalpha but not to the glucocorticoid receptor, as demonstrated by the yeast two-hybrid tests and glutathione S-transferase pull-down assays. These direct interactions were also demonstrated in gel-shift assays, in which the oestrogen response element (ERE) binding by ERalpha was enhanced by the RXRalpha LBD but was abolished by the RARalpha LBD. In addition, we showed that RARalpha and RXRalpha bound the ERE as efficiently as ERalpha, suggesting that competition for DNA binding may affect the transactivation function of the ER. In transient transfection experiments, co-expression of RARalpha or RXRalpha, along with ERalpha or ERbeta, revealed differential modulation of the ERE-dependent transactivation, which was distinct from the results when each receptor alone was co-transfected. Importantly, when the LBD of RARalpha was co-expressed with ERalpha, transactivation of ERalpha on the ERE was repressed as efficiently as when wild-type RARalpha was co-expressed. Furthermore, liganded RARalpha or unliganded RXRalpha enhanced the ERalpha transactivation, suggesting the formation of transcriptionally active heterodimer complexes between the ER and retinoid receptors. Taken together, these results suggest that direct protein-protein interactions may play major roles in the determination of the biological consequences of cross-talk between ERs and RARalpha or RXRalpha.

Estrogen receptor, a common interaction partner for a subset of nuclear receptors

Nuclear receptors regulate transcription by binding to specific DNA response elements as homodimers or heterodimers. Herein, the yeast and mammalian two-hybrid tests as well as glutathione-S-transferase pull-down assays were exploited to demonstrate that estrogen receptor (ER) directly binds to a subset of nuclear receptors through protein-protein interactions between ligand-binding domains. These receptors include hepatocyte nuclear factor 4, thyroid hormone receptor (TR), retinoic acid receptor (RAR), ERbeta, and retinoid X receptor (RXR). In yeast cells, a LexA fusion protein to the human ER ligand-binding domain (LexA/ER-LBD) was an inert transactivator of a LacZ reporter gene controlled by upstream LexA-binding sites. However, LexA/ER-LBD differentially modulated the LacZ reporter gene expression when coexpressed with native TRs, RARs, or RXRs. Similarly, cotransfection of these receptors in CV1 cells up- or down-regulated transactivations by ER. From these results, we propose that ER is a common interaction partner for a subset of receptors, and these interactions should mediate novel signaling pathways in vivo.

IkappaBbeta interacts with the retinoid X receptor and inhibits retinoid-dependent transactivation in lipopolysaccharide-treated cells

To elucidate the molecular action of the NFkappaB inhibitor IkappaBbeta, we isolated a number of IkappaBbeta interactors using the yeast two-hybrid system. These include the retinoid X receptor (RXR), whose interaction with IkappaBbeta is significantly stimulated by the RXR ligand 9-cis-retinoic acid, as shown in the yeast system as well as the glutathione S-transferase pull down assays. RXR is a nuclear protein, whereas IkappaBbeta accumulates in the nucleus only in cells stimulated with lipopolysaccharide or other inducers that result in prolonged activation of NFkappaB. Consistent with this, cotransfection with IkappaBbeta specifically repressed the 9-cis-RA-induced transcriptional activities of RXR in an lipopolysaccharide-dependent manner. These results suggest a novel IkappaBbeta-mediated antagonism between the signaling pathways of NFkappaB and RXR.

Regulation of RAR beta expression by RAR- and RXR-selective retinoids in human lung cancer cell lines: effect on growth inhibition and apoptosis induction

Retinoids regulate the growth and differentiation of human tracheobronchial epithelial cells. In this study, we investigated the effects of all-trans-retinoic acid (trans-RA) and receptor class-selective retinoids on the growth and apoptosis of human lung cancer cell lines. Trans-RA significantly inhibited the growth of Calu-6 and H460 cells, accompanied by induction of RA receptor (RAR) beta expression. In contrast, it had little effect on the growth of H292, SK-MES-1 and H661 lung cancer cell lines, in which RAR beta expression was not induced. Stable expression of RAR beta in RAR beta-negative, trans-RA-resistant SK-MES-1 and H661 lung cancer cells led to recovery of trans-RA-induced growth inhibition, which occurred, however, only at low serum concentration. Using fluorescent microscopy and the terminal deoxyribonucleotidyl transferase (TdT) assay, we demonstrated that induction of apoptosis by trans-RA contributed to its growth-inhibitory effect in trans-RA-sensitive lung cancer cell lines. Analysis of RAR-selective and retinoid X receptor (RXR)-selective retionoids showed that activation of both RARs and RXRs could induce growth inhibition in trans-RA-sensitive lung cancer cells. Also, an additive synergistic effect on growth inhibition and RAR beta induction was observed when cells were treated with combinations of RAR-selective and RXR-selective retinoids. Together, our results show that expression of RAR beta plays a role in mediating retinoid response in lung cancer cells and that activation of RARs or RXRs contributes to induction of RAR beta, growth inhibition and apoptosis by retinoids.

Regulation of RAR beta expression by RAR- and RXR-selective retinoids in human lung cancer cell lines: effect on growth inhibition and apoptosis induction

Retinoids regulate the growth and differentiation of human tracheobronchial epithelial cells. In this study, we investigated the effects of all-trans-retinoic acid (trans-RA) and receptor class-selective retinoids on the growth and apoptosis of human lung cancer cell lines. Trans-RA significantly inhibited the growth of Calu-6 and H460 cells, accompanied by induction of RA receptor (RAR) beta expression. In contrast, it had little effect on the growth of H292, SK-MES-1 and H661 lung cancer cell lines, in which RAR beta expression was not induced. Stable expression of RAR beta in RAR beta-negative, trans-RA-resistant SK-MES-1 and H661 lung cancer cells led to recovery of trans-RA-induced growth inhibition, which occurred, however, only at low serum concentration. Using fluorescent microscopy and the terminal deoxyribonucleotidyl transferase (TdT) assay, we demonstrated that induction of apoptosis by trans-RA contributed to its growth-inhibitory effect in trans-RA-sensitive lung cancer cell lines. Analysis of RAR-selective and retinoid X receptor (RXR)-selective retionoids showed that activation of both RARs and RXRs could induce growth inhibition in trans-RA-sensitive lung cancer cells. Also, an additive synergistic effect on growth inhibition and RAR beta induction was observed when cells were treated with combinations of RAR-selective and RXR-selective retinoids. Together, our results show that expression of RAR beta plays a role in mediating retinoid response in lung cancer cells and that activation of RARs or RXRs contributes to induction of RAR beta, growth inhibition and apoptosis by retinoids.

Modulation of retinoic acid sensitivity in lung cancer cells through dynamic balance of orphan receptors nur77 and COUP-TF and their heterodimerization

The diverse function of retinoic acid (RA) is mediated by its nuclear receptors, the retinoic acid receptors (RARs) and retinoid X receptors (RXRs). However, the RA response is often lost in cancer cells that express the receptors. Previously, it was demonstrated that the RA response is regulated by the COUP-TF orphan receptors. Here, we present evidence that nur77, another orphan receptor whose expression is highly induced by phorbol esters and growth factors, is involved in modulation of the RA response. Expression of nur77 enhances ligand-independent transactivation of RA response elements (RAREs) and desensitizes their RA responsiveness. Conversely, expression of COUP-TF sensitizes RA responsiveness of RAREs by repressing their basal transactivation activity. Unlike the effect of COUP-TFs, the function of nur77 does not require direct binding of nur77 to the RAREs, but is through interaction between nur77 and COUP-TFs. The interaction occurs in solution and results in inhibition of COUP-TF RARE binding and transcriptional activity. Unlike other nuclear receptors, a large portion of the carboxy-terminal end of nur77 is not required for its interaction with COUP-TF. In human lung cancer cell lines, COUP-TF is highly expressed in RA-sensitive cell lines while nur77 expression is associated with RA resistance. Stable expression of COUP-TF in nur77-positive, RA-resistant lung cancer cells enhances the inducibility of RARbeta gene expression and growth inhibition by RA. These observations demonstrate that a dynamic equilibrium between orphan receptors nur77 and COUP-TF, through their heterodimerization that regulates COUP-TF RARE binding, is critical for RA responsiveness of human lung cancer cells.

A novel class of retinoid antagonists and their mechanism of action

Retinoids regulate a broad range of biological processes through two subfamilies of nuclear retinoid receptors, the retinoic acid receptors (RARs) and the retinoid X receptors (RXRs). Recently, we reported a novel type of retinoic acid antagonist (SR11335) and showed that this compound can inhibit retinoic acid (RA)-induced activation of a human immunodeficiency virus type 1 (HIV-1) promoter construct that contains a special RA response element (RARE). We have now further characterized the antagonism mediated by SR11335 and of newly synthesized structurally related compounds. Two compounds, SR11330 and SR11334, which are poor transactivators, also showed antagonist activities, inhibiting all-trans-RA (tRA) and 9-cis-RA. The retinoids inhibited transcriptional activation of RAR/RXR heterodimers effectively, while inhibition of RXR homodimers was less efficient. Inhibition was observed on several RAREs, including the TREpal, betaRARE, apoAI-RARE, and CRBPI-RARE. In addition, the antagonists inhibited tRA-induced differentiation of HL-60 cells. The antagonist did not interfere with DNA binding of the receptors. In limited proteolytic digestion assays, SR11335 induced resistance of the receptors to proteolysis, but the pattern of the degradation was not altered from that induced by tRA, suggesting that these antagonists induce their biological effects by competing with agonists for binding to RARs, thereby preventing the induction of conformational changes of the receptors necessary for transcriptional activation.

Retinoic acid receptor beta mediates the growth-inhibitory effect of retinoic acid by promoting apoptosis in human breast cancer cells

Retinoids are known to inhibit the growth of hormone-dependent but not that of hormone-independent breast cancer cells. We investigated the involvement of retinoic acid (RA) receptors (RARs) in the differential growth-inhibitory effects of retinoids and the underlying mechanism. Our data demonstrate that induction of RAR beta by RA correlates with the growth-inhibitory effect of retinoids. The hormone-independent cells acquired RA sensitivity when the RAR beta expression vector was introduced and expressed in the cells. In addition, RA sensitivity of hormone-dependent cells was inhibited by a RAR beta-selective antagonist and the expression of RAR beta antisense RNA. Introduction of RAR alpha also restored RA sensitivity in hormone-independent cells, but this restoration was accomplished by the induction of endogenous RAR beta expression. Furthermore, we show that induction of apoptosis contributes to the growth-inhibitory effect of RAR beta. Thus, RAR beta can mediate retinoid action in breast cancer cells by promoting apoptosis. Loss of RAR beta, therefore, may contribute to the tumorigenicity of human mammary epithelial cells.

Retinoid receptors in human lung cancer and breast cancer

Retinoids, the natural and synthetic vitamin A derivatives, are known to inhibit the proliferation of lung cancer and breast cancer cells and the growth of carcinogen-induced bronchogenic squamous cell carcinoma and mammary tumors, and have been used as chemoprevention agents against both types of cancer. However, clinical trials of retinoids in patients with advanced lung cancer and breast cancer have not been successful. In studying how retinoid sensitivity is lost in cancer cells, we have found that lack of the retinoic acid receptor beta (RAR beta) gene expression and its abnormal regulation by retinoic acid (RA) are common features in human lung cancer and breast cancer cells. The absence and abnormal RA regulation of RAR beta correlates with the loss of anti-proliferation effect of RA in hormone-independent breast cancer cells, and is due to different abnormalities found in cancer cells. Furthermore, expression of RAR beta gene in hormone-independent breast cancer cells restores their RA sensitivity. These data demonstrate that RAR beta can mediate the growth inhibitory effect of RA and suggest that the lack of RAR beta may contribute to retinoid resistance in certain cancer cells.

Conformational effects on retinoid receptor selectivity. 2. Effects of retinoid bridging group on retinoid X receptor activity and selectivity

The natural retinoid 9-cis-retinoic acid is an activating ligand for both the retinoic acid receptors (RARs) and the retinoid X receptors (RXRs), which are members of the retinoid/thyroid hormone/steroid hormone family of nuclear receptor proteins that activate gene transcription through specific response elements. The pharmacophoric groups necessary to confer RXR selectivity were established by evaluating the ability of 21 conformationally restricted retinoids to activate the TREpal retinoic acid receptor response element for gene transcription in the presence of one of the three RAR subtypes or RXR alpha. In contrast to those retinoids selective for the RARs, these RXR-selective retinoids have one less atom in the bridge linking the hydrophobic and carboxylic acid termini of the retinoid skeleton. Therefore, a one-carbon bridge replaces the 19-methyl group and 9E-double bond of 9-cis-retinoic acid and is further functionalized by inclusion in an isopropylidene group, a dioxolane ring, or a cyclopropane ring for optimal RXR alpha activity and selectivity. In addition, the beta-geranylidene and 20-methyl-(11E,13E)-dienoic acid groups of 9-cis-retinoic acid are replaced by a 5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl ring and a 4-carboxylphenyl ring, respectively, for optimal activation and selectivity. RXR alpha selectivity is reduced on replacement of the 4-carboxylphenyl group by a 2-carboxyl-5-thienyl group or the 9-cis-retinoic acid methylpentadienoic acid terminus.

A retinoic acid response element that overlaps an estrogen response element mediates multihormonal sensitivity in transcriptional activation of the lactoferrin gene

The lactoferrin gene is highly expressed in many different tissues, and its expression is controlled by different regulators. In this report, we have defined a retinoic acid response element (RARE) in the 5'-flanking region of the lactoferrin gene promoter. The lactoferrin-RARE is composed of two AGGTCA-like motifs arranged as a direct repeat with 1-bp spacing (DR-1). A gel retardation assay demonstrated that it bound strongly with retinoid X receptor (RXR) homodimers and RXR-retinoic acid receptor (RAR) heterodimers as well as chicken ovalbumin upstream promoter transcription factor (COUP-TF) orphan receptor. In CV-1 cells, the lactoferrin-RARE linked with a heterologous thymidine kinase promoter was strongly activated by RXR homodimers in response to 9-cis-retinoic acid (9-cis-RA) but not to all-trans-RA. When the COUP-TF orphan receptor was cotransfected, the 9-cis-RA-induced RXR homodimer activity was strongly repressed. A unique feature of the lactoferrin-RARE is that it has an AGGTCA-like motif in common with an estrogen-responsive element (ERE). The composite RARE/ERE contributes to the functional interaction between retinoid receptors and the estrogen receptor (ER) and their ligands. In CV-1 cells, cotransfection of the retinoid and estrogen receptors led to mutual inhibition of the other's activity, while an RA-dependent inhibition of ER activity was observed in breast cancer cells. Furthermore, the lactoferrin-RARE/ERE showed differential transactivation activity in different cell types. RAs could activate the lactoferrin-RARE/ERE in human leukemia HL-60 cells and U937 cells but not in human breast cancer cells. By gel retardation analyses, we demonstrated that strong binding of the endogenous COUP-TF in breast cancer cells to the composite element contributed to diminished RA response in these cells. Thus, the lactoferrin-RARE/ERE functions as a signaling switch module that mediates multihormonal responsiveness in the regulation of lactoferrin gene expression.

Conformationally defined 6-s-trans-retinoic acid analogs. 2. Selective agonists for nuclear receptor binding and transcriptional activity

We recently demonstrated in animal models that a new conformationally defined RA isomer (Vaezi et al. J. Med. Chem. 1994, 37, 4499-4507) was as effective as RA in the prevention of skin papillomas but was less toxic. In order to provide more details concerning this improved action, we report here the preparation of a homologous conformationally defined 6-s-trans-retinoid (1) and investigate its ability to interact with proteins and to activate gene expression. Four configurational isomers of 1 were evaluated in binding assays for cellular retinoic acid binding protein, CRABP (isolated from chick skin); CRABP-I and CRABP-II (cloned from mouse); nuclear retinoic acid receptors (RARs); and nuclear retinoid X receptors (RXRs). In each assay the all-E-isomer of this retinoid had an activity that was comparable to that of (all-E)-RA. However, the 9Z-isomer was at least 200-fold less active than (all-E)-RA in binding to different RARs, while it was only 6-20 times less active than (9Z)-RA in binding to different RXRs. In an in vivo transient transfection assay, the all-E-isomer activated a reporter gene containing a retinoic acid response element (RARE) with efficiency similar to (all-E)-RA when expression vectors for either RAR alpha, RAR beta, RAR gamma alone or RAR alpha together with RXR alpha were cotransfected. In contrast, the 9Z-isomer was much less active than (9Z)-RA in the same assay systems. However, (9Z)-1 efficiently enhanced the DNA binding and transactivational activity of RXR alpha homodimers. Taken together, these studies demonstrate that the all-E- and 9Z-isomers of this retinoid are selective and potent agonists of RAR and RXR binding and activation.

A specific defect in the retinoic acid response associated with human lung cancer cell lines

The effects of retinoic acid (RA) are mainly mediated by its nuclear receptors, the RA receptors (RARs) and retinoid X receptors (RXRs) that regulate target gene expression by binding to specific RA-response elements (RAREs). RAR beta is the best characterized RA-responsive gene. Due to the presence of a RARE (beta RARE) in its promoter, the expression of the RAR beta 2 is markedly increased in response to RA in most epithelial tissues, including lung. Recently, it was observed that the RAR beta gene is not expressed in a number of human lung cancer cell lines, suggesting a possible correlation between abnormal expression of the RAR beta gene and lung cancer development. In this study, we investigate the RA response in human lung cancer cell lines. Here we report that the expression of the RAR beta gene cannot be regulated by RA in the majority of human lung cancer cell lines examined, while the general response to RA is intact. The nonresponsiveness of the RAR beta gene results from different defects in the response mechanism. Interestingly, we find in some cell lines a differential responsiveness of the beta RARE such that the element is inactive in its natural promoter context but active when linked to the heterologous tk promoter. Importantly, we also observe that the presence of retinoid receptors is not sufficient for the induction of the RAR beta gene. This suggests that specific factors determine the RA responsiveness in the context of its natural promoter. Our observation that the RA nonresponsiveness of the RAR beta promoter is a common feature of human lung cancer cell lines suggests that balanced RAR beta expression is an essential feature for the maintenance of a normal state of lung tissue.

A synthetic retinoid antagonist inhibits the human immunodeficiency virus type 1 promoter

Retinoids regulate a broad range of biological processes and affect cell growth and differentiation of many cell types, including the immune system. Recently, it was reported that human immunodeficiency virus type 1 (HIV-1) expression in macrophages is enhanced by retinoic acid (RA). Retinoid signals are mediated by the RA receptors (RARs) and retinoid X receptors (RXRs) that bind to specific RA responsive elements (RAREs) in the promoter region of susceptible genes. Here, we report on a RARE in the long terminal repeat (LTR) region that allows activation of the HIV-1 LTR. The RARE is composed of two consensus RARE half-sites (A/GGGTCA) arranged as a palindrome separated by 9 nucleotides and is activated by both RAR/RXR heterodimers and RXR homodimers. We show that the COUP (chicken ovalbumin upstream promoter) orphan receptors also bind to the HIV-1 RARE and repress the retinoid response of the HIV-1 RARE or the HIV-1 LTR. Furthermore, a newly discovered synthetic retinoid is shown to be a potent inhibitor of retinoid-induced activation of the HIV-1 RARE. These observations suggest additional approaches for the inhibition of HIV replication.

Mutations that alter ligand-induced switches and dimerization activities in the retinoid X receptor

The retinoid X receptor (RXR) heterodimerizes with a variety of nuclear receptors. In addition, RXR forms homodimers in the presence of its ligand, 9-cis-retinoic acid. From deletion and point mutation analysis we present evidence that a short region (amino acids 413 to 443) in the carboxy terminus of RXR alpha is critical for both homo- and heterodimeric interactions as well as for diverse functional activities. In addition, we present evidence that homo- and heterodimer functions can be separated. The deletion of 19 amino acids from the C-terminal end of RXR dramatically reduced the transcriptional activation function of RXR. The removal of 10 additional amino acids resulted in a receptor (delta RXR3) that had completely lost its ligand-dependent homodimer function but retained its heterodimer activities. Heterodimer function was abolished by the deletion of an additional 20 amino acids. Single amino acid substitutions in the region generated receptors with altered RXR homodimer DNA binding, while simultaneous mutation of three Leu residues (Leu-418, -419 and -422) completely abolished both RXR homodimer and heterodimer DNA binding activities. Mutation of Leu-430 to Phe (L430-F) resulted in a receptor that bound to DNA strongly as homodimers in a ligand-independent manner, while another single amino acid exchange (L422-Q) led to a mutant that behaved in a manner exactly opposite to that of wild-type RXR in that the homodimerization of the mutant occurred in the absence of ligand and was inhibited by 9-cis-retinoic acid. In transfection assays, both L422-Q and L430-F failed to act as homodimers but retained their heterodimer function. Our studies demonstrate the unique properties of the RXR ligand binding domain and point to specific residues that mediate homo- and heterodimer activities and ligand-induced conformational switches.

Recombinant human retinoic acid receptor beta. Binding of synthetic retinoids and transcriptional activation

All-trans-retinoic acid mediates cell growth and differentiation by binding to and then activating nuclear retinoid receptor proteins that regulate gene transcription. Recombinant human retinoic acid receptor beta was cloned and expressed in Escherichia coli as a fusion protein rMBP-RAR beta with maltose-binding protein to facilitate purification. After isolation from bacterial lysates, rMBP-RAR beta was used for binding with selected retinoids. Scatchard analysis with [11,12-3H2]all-trans-retinoic acid gave a Kd of 0.34 nM. Competitive binding studies with a series of conformationally restricted aromatic retinoids indicated that the Ki values for binding to rMBP-RAR beta correlated with the logs of the EC50 values for gene transcriptional activation (p < or = 0.05) and with those for the relative activation compared to that of all-trans-retinoic acid (p < or = 0.01). Inspection of binding-activation correlation diagrams indicates candidate structures for improved retinoid agonists or antagonists.

Formation of retinoid X receptor homodimers leads to repression of T3 response: hormonal cross talk by ligand-induced squelching

Thyroid hormone receptors (TRs) form heterodimers with retinoid X receptors (RXRs). Heterodimerization is required for efficient TR DNA binding to most response elements and transcriptional activation by thyroid hormone. RXRs also function as auxiliary proteins for several other receptors. In addition, RXR alpha can be induced by specific ligands to form homodimers. Here we report that RXR-specific retinoids that induce RXR homodimers are effective repressors of the T3 response. We provide evidence that this repression by RXR-specific ligands occurs by sequestering of RXR from TR-RXR heterodimers into RXR homodimers. This ligand-induced squelching may represent an important mechanism by which RXR-specific retinoids and 9-cis retinoic acid mediate hormonal cross talk among a subfamily of nuclear receptors activated by structurally unrelated ligands.

Effects of Brazilin on glucose oxidation, lipogenesis and therein involved enzymes in adipose tissues from diabetic KK-mice

In order to address the hypoglycemic mechanism of brazilin, effects on glucose metabolism in epididymal adipose tissue from diabetic KK-mice were investigated. Brazilin remarkably lowered non fasting plasma glucose level without any changes in plasma insulin level. Brazilin significantly increased the rate of glucose oxidation and lipogenesis only in the presence of insulin. Activities of glucose-6 phosphate dehydrogenase and fatty acid synthetase, involved in glucose oxidation and lipogenesis respectively, were significantly increased. These results suggest that brazilin might exert hypoglycemic action in insulin resistance state by, at least in part, regulating the enzymatic reaction process involved in glucose metabolism.

Identification of human liver aldehyde dehydrogenases that catalyze the oxidation of aldophosphamide and retinaldehyde

Biotransformation of the biologically and pharmacologically important aldehydes, retinaldehyde and aldophosphamide, is mediated, in part, by NAD(P)-dependent aldehyde dehydrogenases catalyze the oxidation of the aldehydes to their respective acids, retinoic acid and carboxyphosphamide. Not known at the onset of this investigation was which of the several known human aldehyde dehydrogenases (ALDHs) catalyze these reactions. Thus, human liver aldehyde dehydrogenases were chromatographically resolved and the ability of each to catalyze the oxidation of retinaldehyde and aldophosphamide was assessed. Only one, namely ALDH-1, catalyzed the oxidation of retinaldehyde; the Km value was 0.3 microM. Three, namely ALDH-1, ALDH-2 and succinic semialdehyde dehydrogenase, catalyzed the oxidation of aldophosphamide; Km values were 52, 1193, and 560 microM, respectively. ALDH-4, ALDH-5 and betaine aldehyde dehydrogenase did not catalyze the oxidation of either aldophosphamide or retinaldehyde. ALDH-1 and succinic semialdehyde dehydrogenase accounted for 64 and 30%, respectively, of the total hepatic aldehyde dehydrogenase-catalyzed aldophosphamide (160 microM) oxidation. ALDH-1-catalyzed oxidation of aldophosphamide was noncompetitively inhibited by chloral hydrate; the Ki value was 13 microM. ALDH-2- and succinic semialdehyde dehydrogenase-catalyzed oxidation of aldophosphamide was relatively insensitive to inhibition by chloral hydrate. These observations strongly suggest an important in vivo role for ALDH-1 in the catalysis of retinaldehyde and aldophosphamide biotransformation. Succinic semialdehyde dehydrogenase-catalyzed biotransformation of aldophosphamide may also be of some in vivo importance.

Asymmetrical retinoic acid synthesis in the dorsoventral axis of the retina

An aldehyde dehydrogenase present at high levels in the dorsal retina of the embryonic and adult mouse was identified as the isoform AHD-2 known to oxidize retinaldehyde to retinoic acid. Comparative estimates of retinoic acid levels with a reporter cell line placed the retinas among the richest tissues in the entire body of the early embryo; levels in ventral retina, however, exceeded dorsal levels. Retinoic acid synthesis from retinaldehyde in the dorsal pathway was less effective than the ventral pathway at low substrate levels and more effective at high levels. The dorsal pathway was preferentially inhibited by disulfiram, while ventral synthesis was preferentially inhibited by p-hydroxymercuribenzoate. When protein fractions separated by isoelectric focusing were analyzed for retinoic acid synthesizing capacity by a zymography-bioassay, most of the synthesis in dorsal retina was found to be mediated by AHD-2, and ventral synthesis was mediated by dehydrogenase activities distinct in charge from AHD-2. Postnatally, levels of highest retinoic acid synthesis shifted from ventral to dorsal retina. In the adult retina, the dorsal pathway persisted, but the preferential ventral pathway was no longer detectable. Our observations raise the possibility that retinoic acid plays a role in the determination and maintenance of the dorsoventral axis of the retina, and that the morphogenetically significant asymmetry here lies in the spatial arrangement of synthetic pathways.

Identification of mouse liver aldehyde dehydrogenases that catalyze the oxidation of retinaldehyde to retinoic acid

NAD(P)-linked aldehyde dehydrogenases catalyze the oxidation of a wide variety of aldehydes. Thirteen of these enzymes have been identified in mouse tissues; eleven are found in the liver. Some are substrate-nonspecific; others are relatively substrate-specific. The present investigation sought to determine which of these enzymes are operative in catalyzing the oxidation of retinaldehyde to retinoic acid, a metabolite of vitamin A that promotes the differentiation of epithelial and other cells. Spectrophotometric and HPLC assays were used for this purpose. Enzyme-catalyzed oxidation of retinaldehyde (25 microM) was restricted to the cytosol (105,000 g supernatant fraction) and occurred at a rate of 211 nmol/min/g liver; oxidation of acetaldehyde (4 mM) by this fraction proceeds about ten times faster. At least 90% of this activity was NAD dependent. Of the approximately 10% that was apparently NAD independent, two-thirds was inhibited by 1 mM pyridoxal, a known inhibitor of aldehyde oxidase. Of the six cytosolic aldehyde dehydrogenases, only two, viz. AHD-2 and AHD-7, catalyzed the oxidation of retinaldehyde to retinoic acid. An additional NAD-dependent enzyme, viz. xanthine oxidase (dehydrogenase form), also catalyzed the reaction. Catalysis by AHD-2 accounted for more than 90% of the total NAD-dependent activity. Km values were 0.7, 0.6 and 0.9 microM, respectively, for the AHD-2-, AHD-7- and xanthine oxidase (dehydrogenase form)-catalyzed reaction. AHD-4, an aldehyde dehydrogenase found in the cytosol of mouse stomach epithelium and cornea, did not catalyze the reaction.

Sinus histiocytosis with massive lymphadenopathy and tracheobronchial lesions: CT and MR findings

The CT and magnetic resonance findings are presented in a case of tracheal occlusion due to sinus histiocytosis with massive lymphadenopathy.

Temperature and pH dependence of fluocinolone acetonide degradation in a topical cream formulation

We investigated the degradation of fluocinolone acetonide (FA) incorporated into an oil-in-water cream base. The study examined the influence of temperature (23 to 80 degrees C) and cream pH (pH 2.3 to 6) on FA degradation rates. FA degradation followed pseudo-first-order kinetics and adhered to the Arrhenius expression over the entire temperature range investigated. At all temperatures, the pH strongly influenced the observed degradation rate constant (kobs) values, with rate minima observed near pH 4. The FA log(degradation rate)-pH profiles were consistent with a reaction mechanism requiring drug hydrolysis catalyzed by hydroxide and hydrogen ions. Taking into account both the temperature and the pH dependence of FA degradation permits calculating kobs values from the following equation: kobs = exp[22.5 - (17,200/RT)] + exp[38.7 - (22,200/RT)] x [H+] + exp[49.5 - (21,100/RT)] x [OH-] where the three bracketed terms represent Arrhenius expressions for neutral, acid-catalyzed, and base-catalyzed hydrolysis reactions. FA degradation in the cream base parallels the degradation of a related steroid (triamcinolone acetonide) in an aqueous alcohol solution. The equivalence between FA and triamcinolone acetonide kinetics in the different reaction media suggests that in the cream base, FA degradation is limited to an aqueous phase largely unperturbed by the presence of nonaqueous constituents that comprise the cream formulation.

Effects of dimethyl sulfoxide and acupuncture on the cardiovascular system of dogs

The intravenous administration of dimethyl sulfoxide (100 mg/kg) resulted in a significant increase in cardiac output, stroke volume, central venous pressure, and a significant decrease in heart rate. Acupuncture by electrocautery at Jen Chung (Go-26) produced a significant increase in cardiac output, stroke volume, heart rate, mean arterial pressure, and pulse pressure and a significant decrease in total peripheral resistance in dogs under 0.75% halothane anesthesia. Both DMSO and acupuncture elicit an analgesic effect and enhance cardiovascular function as exemplified by an increase in the cardiac output.

Inhibition of the cardiovascular effects of lysine acetylsalicylate by propranolol in dogs during halothane anaesthesia

The cardiovascular effects of lysine acetylsalicylate and/or propranolol were studied in 26 dogs. All animals were maintained under anaesthesia with halothane 0.75 per cent, supplemented by the intravenous administration of succinylcholine to allow controlled ventilation during a two hour period of monitoring. Cardiac output, stroke volume, heart rate, mean arterial pressure, pulse pressure, central venous pressure, total peripheral resistance, pH, Paco2, pao2 and base deficit were measured in each dog. Lysine acetylsalicylate 50 mg . kg-1, administered alone as a single bolus, significantly (P less than 0.05) increased the cardiac output and stroke volume and significantly decreased the heart rate, central venous pressure and total peripheral resistance in dogs under halothane anaesthesia. Propranolol hydrochloride 0.5 mg . kg-1 as a single intravenous bolus was followed by a significant decrease in cardiac output, heart rate and mean arterial pressure and a significant increase in central venous pressure and total peripheral resistance. The administration of propranolol prior to lysine acetylsalicylate resulted in a significant decrease in cardiac output and heart rate. Pretreatment with propranolol was effective in inhibiting the positive inotropic effect of lysine acetylsalicylate.

Effect of ether, ethanol and aqueous extracts of ginseng on cardiovascular function in dogs

Ether, ethanol and aqueous extracts of ginseng were serially prepared from Korean ginseng plants. Each extract in the dose of 40 mg/kg was administered intravenously to ten dogs under light halothane anesthesia while 11 cardiovascular variables were compared during the ensuing two hours. The variable included cardiac output, stroke volume, heart rate, mean arterial pressure, pulse pressure, central venous pressure, total peripheral resistance, pH, PaCO2, PaO2 and base deficit. Following the administration of the ether extract (40 mg/kg) the heart rate and the central venous pressure decreased significantly. The administration of ethanol extract (40 mg/kg) caused a significant decrease in the heart rate and the mean arterial pressure. After the administration of the aqueous extract (40 mg/kg) the cardiac output, stroke volume and central venous pressure were significantly decreased, while the total peripheral resistance was significantly increased.

Reversal by acupuncture of cardiovascular depression induced with morphine during halothane anaesthesia in dogs

The cardiovascular effects of morphine sulphate and/or acupuncture by means of electrocautery at Jen Chung (Go-26) were studied in 35 dogs. All animals were maintained under anaesthesia with halothane 0.75 per cent supplemented by the intravenous administration of succinylcholine to allow controlled ventilation during a two hour period of monitoring. Cardiac output, stroke volume, heart rate, mean arterial pressure, pulse pressure, central venous pressure, total peripheral resistance, [H+] (pH) PaCO2, PaO2 and base deficit were measured in each dog. Morphine 0.5 mg . kg-1, administered alone as a single bolus, significantly (P less than 0.05) decreased cardiac output, heart rate, mean arterial pressure, and significantly increased stroke volume and pulse pressure in dogs under halothane anaesthesia. Acupuncture by electrocautery alone induced a significant increase in cardiac output, stroke volume, heart rate, mean arterial pressure and pulse pressure with a significant decrease in total peripheral resistance following halothane. Acupuncture at Jen Chung (Go-26) for 10 minutes following the intravenous administration of morphine caused a significant increase in cardiac output, heart rate and mean arterial pressure with a significant decrease in central venous pressure and total peripheral resistance during halothane anaesthesia. The depressant effect of morphine on cardiac output, heart rate and mean arterial pressure in dogs under halothane anaesthesia appears to be reversed by acupuncture by electrocautery at Jen Chung (Go-26). Stimulation of this acupuncture locus could be helpful in resuscitating patients whose cardiovascular system is depressed by morphine and/or halothane anaesthesia.

Comparison of sodium salicylate, morphine sulfate, and acupuncture at Jen-Chung (Go-26) on the cardiovascular system of dogs

The cardiovascular effects of the administration of sodium salicylate (100 mg/kg), the administration of morphine sulfate (0.5 mg/kg) and acupuncture by electrocautery at Jen-Chung (Go-26) were compared in groups of dogs under 0.75% halothane anesthesia. Cardiac output (CO), stroke volume (SV), heart rate (HR), mean arterial pressure (MAP), pulse pressure (PP), central venous pressure (CVP), total peripheral resistance (TPR), pH, PaCO2, PaO2 and base deficit were measured over a two hour period. A significant increase in CO, SV, PP, and CVP in addition to a significant decrease in TPR were observed following the administration of sodium salicylate. Morphine sulfate decreased the CO, HR, and MAP significantly while the SV and PP were significantly increased. Acupuncture by electrocautery at Jen-Chung (Go-26) produced a significant increase in CO, SV, HR, MAP, and PP and a significant decrease in TPR. This model was satisfactory in comparing cardiovascular changes evoked by a mild analgesic, sodium salicylate, a potent opiate, morphine sulfate, and acupuncture by electrocautery at Jen-Chung (Go-26).

Can naloxone inhibit the cardiovascular effect of acupuncture?

Forty dogs were studied during MAC-1 halothane anesthesia with a chronically implanted electromagnetic flow probe on the ascending aorta. Cardiac output, stroke volume, heart rate, mean arterial pressure, pulse pressure, central venous pressure and total peripheral resistance were determined in addition to Pao2, pH, Paco2 and base deficit. Acupuncture moxibustion with electrocautery at Jen Chung (Go-26) produced a significant (five per cent level) increase in the cardiac output, stroke volume, heart rate, mean arterial pressure and pulse pressure and a significant decrease in total peripheral resistance during a 120-minute period of observation in dogs under halothane anaesthesia. Acupuncture moxibustion at Go-26 following pretreatment with the narcotic antagonist naloxone (1 mg.kg-1) produced a significant increase in cardiac output, heart rate, mean arterial pressure. It is concluded that naloxone, which inhibits the analgesic effects of acupuncture, does not inhibit the symphathomimetic effect of acupuncture or moxibustion at Jen Chung (Go-26) in dogs under light MAC-1 halothane anaesthesia.