Muscular Echo-Intensity of the Quadriceps by Ultrasound Is More Related to Improvement of Gait Independence than Muscle Thickness in Older Inpatients.

OBJECTIVES: This study aimed to examine whether the decrease in muscular echo-intensity of the quadriceps by ultrasound in older inpatients is related to the improvement of gait independence than the increase of muscle thickness. DESIGN: Longitudinal study. SETTING: Hospital-based study. PARTICIPANTS: This study included 171 inpatients aged ≥ 65 years (median age: 84.0 [77.0-88.0], 56.1% female). Patients who were able to walk independently at hospital admission were excluded from the study. MEASUREMENTS: Improvement of gait independence during hospital stay was assessed using the change in Functional Independence Measure (FIM) gait score (i.e., FIM gait score at hospital discharge minus FIM gait score at hospital admission) and FIM gait score at hospital discharge. Muscular echo-intensity and muscle thickness of the quadriceps were assessed at hospital admission and discharge using ultrasound images, respectively. Muscular echo-intensity has been shown to be mainly related to intramuscular adipose tissue. Multiple linear regression analysis was performed to identify the factors independently associated with the change in FIM gait score and FIM gait score at discharge. RESULTS: Change in quadriceps echo-intensity was independently and significantly associated with the change in FIM gait score (ß = -0.22, p = 0.017) and FIM gait score at hospital discharge (ß = -0.21, p = 0.017). In contrast, change in quadriceps thickness was not independently and significantly associated with the change in FIM gait score (ß = 0.16, p = 0.050) and FIM gait score at hospital discharge (ß = 0.15, p = 0.050). CONCLUSIONS: Our study indicates that a decrease in muscular echo-intensity of the quadriceps by ultrasound is more related to the improvement of gait independence than an increase of muscle thickness in older inpatients. Intervention for intramuscular adipose tissue of the quadriceps may be important for improving gait independence in older inpatients.

Higher Body Mass Index in Hospitalized Older Patients Is Related to Higher Muscle Quality.

OBJECTIVES: This study aimed to examine the relationship between muscle mass, intramuscular adipose tissue, and body mass index (BMI) in older inpatients. DESIGN: Cross-sectional study. SETTING: Hospital-based study. PARTICIPANTS: This study included 413 inpatients aged ≥ 65 years (186 men and 227 women). MEASUREMENTS: Muscle mass and intramuscular adipose tissue of the quadriceps were assessed by measuring the muscle thickness and echo intensity on ultrasound images. To examine the relationship between quadriceps thickness and echo intensity and BMI in total participants and each sex, the Kendall rank correlation coefficient was used. Multiple regression analysis was performed to examine whether BMI was independently and significantly related to the quadriceps thickness and echo intensity, even after adjusting for other variables for total participants and each sex. The independent variables in multiple regression analyses were BMI, age, disease, days from onset disease. RESULTS: The results of the correlation analyses showed that BMI was significantly related to the quadriceps thickness (total participants, τ = 0.431; men, τ = 0.491; women, τ = 0.388) and echo intensity (total participants, τ = -0.239; men, τ = -0.318; women, τ = -0.188). In the multiple regression analysis, BMI was independently and significantly associated with the quadriceps thickness (total participants, ß = 0.535; men, ß = 0.548; women, ß = 0.519) and echo intensity (total participants, ß = -0.287; men, ß = -0.398; women, ß = -0.210). CONCLUSION: This study indicated that older inpatients with a higher BMI have greater muscle mass and less intramuscular adipose tissue of the quadriceps. These results suggested that a higher BMI in older inpatients is related to higher quadriceps muscle quality.

Blockade of Th1 chemokine receptors ameliorates pulmonary granulomatosis in mice.

Sarcoidosis is a granulomatous disease of unknown aetiology. We identified immunological targets for the treatment of pulmonary granulomatosis using a murine model generated with Propionibacterium acnes. Sensitisation and challenge using heat-killed P. acnes and dendritic cells (DCs) were performed to produce pulmonary granulomatosis in C57BL/6 mice. Immunological analyses using ELISA as well as cDNA microarray analysis were used to search for cytokines or chemokines associated with the formation of granulomas in the lungs. Co-administration of P. acnes and DCs reproducibly induced the formation of pulmonary granulomas, which resembled sarcoid granulomas. The cDNA microarray assay demonstrated that the gene expression of CXCL9 and CXCL10, ligands for CXCR3, and of CCL4, a ligand for CCR5, was strongly upregulated during granulomatosis. ELISA confirmed that levels of CXCL9 and CXCL10 as well as T-helper (Th)1 cytokines and chemokines including tumour necrosis factor-α and interferon-γ were elevated in bronchoalveolar lavage fluid (BALF). The blockade of Th1 chemokine receptors using TAK-779, a dual blocker for CXCR3 and CCR5, led to reduced numbers of CXCR3+CD4+ and CCR5+CD4+ T-cells in BALF. Furthermore, administration of TAK-779 ameliorated the granulomatosis. The targeted inhibition of Th1 chemokines might be useful for inhibiting Th1-biased granulomatous diseases, including sarcoidosis.

Interspecies diversity of the occludin sequence: cDNA cloning of human, mouse, dog, and rat-kangaroo homologues.

Occludin has been identified from chick liver as a novel integral membrane protein localizing at tight junctions (Furuse, M., T. Hirase, M. Itoh, A. Nagafuchi, S. Yonemura, Sa. Tsukita, and Sh. Tsukita. 1993. J. Cell Biol. 123:1777-1788). To analyze and modulate the functions of tight junctions, it would be advantageous to know the mammalian homologues of occludin and their genes. Here we describe the nucleotide sequences of full length cDNAs encoding occludin of rat-kangaroo (potoroo), human, mouse, and dog. Rat-kangaroo occludin cDNA was prepared from RNA isolated from PtK2 cell culture, using a mAb against chicken occludin, whereas the others were amplified by polymerase chain reaction based on the sequence found around the human neuronal apoptosis inhibitory protein gene. The amino acid sequences of the three mammalian (human, murine, and canine) occludins were very closely related to each other (approximately 90% identity), whereas they diverged considerably from those of chicken and rat-kangaroo (approximately 50% identity). Implications of these data and novel experimental options in cell biological research are discussed.

SoxD: an essential mediator of induction of anterior neural tissues in Xenopus embryos.

Vertebrate neurogenesis is initiated by the organizer factors that inhibit antineuralizing activities of bone morphogenetic proteins (BMPs) in the ectoderm. Here, we report a candidate mediator of neuralization, SoxD. Expression of SoxD starts at late blastula stages widely in the prospective ectoderm and becomes restricted to the dorsal ectoderm by mid-gastrula stages. SoxD expression is enhanced by the neural inducer Chordin and is suppressed by BMP4 and its downstream genes. Microinjection of SoxD mRNA causes ectopic formation of neural tissues in vivo and induces neural and neuronal markers in the isolated animal cap. Injection of a dominant-negative form of SoxD mRNA can block neuralization of ectoderm caused by attenuation of BMP signals and can strongly suppress formation of anterior neural tissues in vivo. These data show that SoxD functions as an essential mediator of downstream signaling of neural induction.

Pathogenesis of cBFL in common with IPF? Correlation of IP-10/TARC ratio with histological patterns.

BACKGROUND: A Th1 predominant immune response has been shown in acute hypersensitivity pneumonitis. Predominance of Th2 appears to favour the development of pulmonary fibrosis through the profibrotic process and has been described as crucial in the progression of idiopathic pulmonary fibrosis. Chronic bird fancier's lung (cBFL) can present with a histological pattern of usual interstitial pneumonia (UIP)-like lesions. Little is known about the Th1/Th2 balance in the pathogenesis of cBFL. METHODS: To evaluate the relevance of Th1-type chemokines (interferon-inducible protein, IP-10) and Th2-type chemokines (thymus- and activation-regulated chemokine, TARC) and their receptors (CXCR3 and CCR4) to the histological patterns of cBFL, 40 patients with cBFL who underwent surgical lung biopsies, 12 with acute BFL (aBFL) and 10 healthy volunteers were analysed. IP-10 and TARC levels in serum and bronchoalveolar lavage (BAL) fluid were measured by ELISA. Immunohistochemistry for CXCR3 and CCR4 was performed on surgical lung specimens. RESULTS: The ratio of TARC to IP-10 in the serum of patients with UIP-like lesions was significantly higher than in patients with cNSIP/OP-like lesions, aBFL and healthy volunteers. The ratio of CCR4 to CXCR3 in patients with UIP-like lesions was significantly higher than in those with cNSIP/OP-like lesions and fNSIP-like lesions. The ratio of CCR4-positive to CXCR3-positive cells correlated with the ratio of TARC to IP-10 in serum. CONCLUSIONS: A Th2 predominant immune response may play an important role in the development of UIP-like lesions, as already observed in idiopathic pulmonary fibrosis. A Th1 predominance may play a role in the development of cNSIP/OP-like lesions in cBFL.

Molecular and enzymatic characterization of betaC-S lyase in Streptococcus constellatus.

BACKGROUND/AIMS: Streptococcus anginosus and Streptococcus constellatus are frequently isolated from dental abscesses and other suppurative lesions. We previously reported that betaC-S lyase from a strain of S. anginosus produced significantly more hydrogen sulfide than betaC-S lyases from other streptococci. The purpose of this study was to establish the molecular and enzymatic features of the betaC-S lyase in S. constellatus and to elucidate whether this unique capacity is common to many strains of S. constellatus and S. anginosus. METHODS: The capacity of crude extract to produce hydrogen sulfide was evaluated among 16 strains of S. constellatus, S. anginosus, and Streptococcus gordonii. The lcd gene encoding betaC-S lyase was cloned from the genomic DNA of each strain to compare the deduced amino acid sequences. The recombinant betaC-S lyases of three representative strains were purified and characterized. RESULTS: Incubation of crude extracts from all strains of S. constellatus and S. anginosus with l-cysteine resulted in the production of a large amount of hydrogen sulfide. The primary sequence of betaC-S lyase was very similar among strains of S. constellatus and S. anginosus. The kinetic properties of the betaC-S lyases purified from S. constellatus resembled those for betaC-S lyases purified from S. anginosus. In contrast, the betaC-S lyases of S. constellatus and S. gordonii differed in terms of their hydrogen sulfide production, with the former producing much more. CONCLUSION: A high level of hydrogen sulfide production, which appears to be a common feature in both S. constellatus and S. anginosus, may be associated with their abscess formation.

Characteristics of taurine transport system and its developmental pattern in mouse cerebral cortical neurons in primary culture.

Developmental patterns and pharmacological and biochemical properties of taurine transport system were investigated using developing primary cultured neurons prepared from mouse cerebral cortex by trypsin treatment. [3H]Taurine was incorporated into neurons via a high-affinity transport system of which the Km value as well as the Vmax value increased during neuronal development in vitro. This transport system was also inhibited by sodium withdrawal from incubation medium and exposures for 15 h to several metabolic inhibitors such as 2,4-dinitrophenol and monoiodoacetate. In addition, [3H]taurine uptake in both neurons cultured for 3 and 14 days was competitively inhibited by beta-alanine, guanidinoethanesulfonate and hypotaurine. Cysteic acid and cysteine sulfinic acid, metabolic intermediates produced in the process of taurine biosynthesis in the brain from cysteine, induced significant reductions in [3H]taurine uptake in both types of cultured neurons, while cysteine, isethionic acid, cysteamine and cystamine exhibited no alterations in [3H]taurine transport. Moreover, non-competitive inhibition of [3H]taurine uptake by cysteic acid was observed in both neurons. These results clearly indicate that taurine uptake was mediated by the sodium- and energy-dependent transport system with high affinity in 14-day-old neurons as well as neurons cultured for 3 days and that both the Km and Vmax values of this transport system increase during neuronal development in vitro. The results described above suggest that the decrease in taurine content observed in developing brain is unlikely to be due to alteration in the capacity of the taurine transport system during neuronal development.

Molecular cloning of glycoprotein antigens MGP57/53 recognized by monoclonal antibodies raised against bovine milk fat globule membrane.

A cDNA encoding 57 kDa and 53 kDa antigens (MGP57/53) recognized by monoclonal antibodies raised against bovine milk fat globule membrane (MFGM) (Biochim. Biophys. Acta 1199 (1994) 87-95) was cloned from lactating bovine mammary gland by a combination of reverse transcriptase-coupled polymerase chain reaction (RT-PCR) and 3'-rapid amplification of cDNA ends (3'-RACE). The deduced amino-acid sequence showed that mature MGP57/53 consists of 409 amino-acid residues and the calculated molecular weight and isoelectric point are 45,544 and 6.42, respectively. Computer analysis reveals that it has a significant similarity to mouse mammary epithelial cell surface protein, MFG-E8 and a human breast tumor-associated glycoprotein antigen, BA46-1. An N-terminal cysteine-rich domain and a C-terminal tandemly repeated sequence were highly conserved among them, but bovine MGP57/53 lacks 36 amino-acid residues containing a cluster of 5 prolines found in mouse MFG-E8. Northern blot analysis showed that the cDNA hybridized to about 2.0 kb mRNA of lactating bovine mammary gland. These results strongly support our previous report that the two MFGM antigens originate from a single gene and are isoforms with different N-linked sugar chains.

Structure and expression of the mouse S10 gene.

We previously reported the cloning of a human S10 cDNA which encodes a small GTP-binding protein belonging to the Rab subfamily. Here we describe a mouse S10 cDNA and its genomic structure. Mouse S10 is 92.3% homologous at the nucleotide level and 98.3% identical at the amino acid level compared to human S10. The mouse S10 gene is comprised of two exons and a single intron. Northern blotting of tissue RNAs indicates that the S10 gene is predominantly expressed in brain.

The C-terminal tail of the rat lutropin/choriogonadotropin (CG) receptor independently modulates human (h)CG-induced internalization of the cell surface receptor and the lysosomal targeting of the internalized hCG-receptor complex.

The analysis of 21 progressive truncations of the C-terminal tail of the rat LH/CG receptor (rLHR) revealed the presence of a region delineated by residues 628-649 that, when removed, enhanced the degradation of the internalized human (h)CG. The analysis of these truncations also revealed the presence of a region delineated by residues 624-631 that, when removed, enhanced the rate of internalization of hCG. Since there is little overlap between these two regions, we conclude that the structural features of the rLHR that mediate internalization and degradation of the internalized hormone are different. Detailed analyses of cells expressing a truncation at Y637 (designated rLHR-t637) showed that the enhanced degradation of hCG observed in the these cells is due to an increase in the rate of transfer of the internalized hCG-rLHR complex from the endosomes to the lysosomes rather than to the enhanced dissociation of the hCG-rLHR complex in the lysosomes.

Identification of two distinct structural motifs that, when added to the C-terminal tail of the rat LH receptor, redirect the internalized hormone-receptor complex from a degradation to a recycling pathway.

We show that most of the internalized rat LH receptor is routed to a lysosomal degradation pathway whereas a substantial portion of the human LH receptor is routed to a recycling pathway. Chimeras of these two receptors identified a linear amino acid sequence (GTALL) present near the C terminus of the human LH receptor that, when grafted onto the rat LH receptor, redirects most of the rat LH receptor to a recycling pathway. Removal of the GTALL sequence from the human LH receptor failed to affect its routing, however. The GTALL sequence shows homology with the C-terminal tetrapeptide (DSLL) of the beta2-adrenergic receptor, a motif that has been reported to mediate the recycling of the internalized beta2-adrenergic receptor by binding to ezrin-radixin-moesin-binding phosphoprotein-50. Addition of the DSLL tetrapeptide to the C terminus of the rat LH receptor also redirects most of the internalized rat LH receptor to a recycling pathway but, like the recycling of the human LH receptor, this rerouting is not mediated by ezrin-radixin-moesin-binding phosphoprotein-50. We conclude that most of the internalized rat LH receptor is degraded because its C-terminal tail lacks motifs that promote recycling and that two distinct, but homologous, motifs (DSLL at the C terminus or GTALL near the C terminus) can reroute the internalized rat LH receptor to a recycling pathway that is independent of ezrin-radixin-moesin-binding phosphoprotein-50.

p120 acts as a specific coactivator for 9-cis-retinoic acid receptor (RXR) on peroxisome proliferator-activated receptor-gamma/RXR heterodimers.

p120 was originally isolated as a novel nuclear co-activator for thyroid hormone receptor. In this study, we characterized its interaction and transactivation of peroxisome proliferator-activated receptor-gamma (PPARgamma) and 9-cis-retinoic acid receptor (RXR) heterodimers. Transient transfection study revealed that p120 enhanced the transcriptional activation of PPARgamma/RXR induced by PPARgamma- or RXR-specific ligands. In the glutathione-S-transferase pull-down assay, while steroid receptor coactivator-1 showed apparent interactions with both RXR and PPARgamma, p120 bound only to RXR in a 9-cis-retinoic acid (RA)-dependent manner and also did not bind to PPARgamma even in the presence of thiazolidinediones. The yeast two-hybrid analysis showed no interaction of p120 with PPARgamma under any conditions, and electophoretic mobility shift assay showed apparent DNA-PPARgamma/RXR/p120 complex formation only in the presence of 9-cis-RA. Furthermore, the yeast three-hybrid assay clearly revealed a significant interaction between p120 and PPARgamma via RXR of PPARgamma/RXR heterodimer only in the presence of 9-cis-RA. These findings indicate that p120 acts as a specific co-activator for the RXR of PPARgamma/RXR heterodimer in a 9-cis-RA-dependent manner.

Relationship between the SF-36 questionnaire and patient's satisfaction following halitosis therapy.

OBJECTIVE: To assess the health-related quality of life (HRQOL) of patients complaining of halitosis at their first visit and at a later time when their complaint had diminished following therapy, using a self-administered questionnaire, the Medical Outcome Study Short Form-36 (SF-36). The aim of this study was to examine the relationship between HRQOL of patients before and after self-reported disappearance of their complaint following oral hygiene improvements for halitosis. SUBJECTS AND METHODS: Seventy patients of our special clinic for halitosis served as subjects. At the first visit, each completed the SF-36 before determination of volatile sulfur compound (VSC) concentration in mouth air. After excluding dropouts, the same measurements were performed for subjects whose self-reported complaint had disappeared following oral hygiene therapy. RESULTS AND DISCUSSION: At the initial visit, SF-36 scale scores for general health, vitality, social functioning, role-emotion, and mental health were significantly lower when compared with the national averages in Japan. For subjects with self-reported disappearance of complaint, only social functioning rose significantly among SF-36 scores at the end of the study. These results suggest that an awareness of improvement in social life could be related to patient's satisfaction with halitosis oral hygiene therapy.

The analysis of characteristics of elderly people with high VSC level.

OBJECTIVE: The purpose of this study was to examine the characteristics of elderly subjects who had objectionable levels of volatile sulfur compound (VSC). SUBJECTS AND METHOD: In 2002, a total of 115 85-year-old persons in Japan were subjected to oral examinations, tongue coat collections, measurements of VSCs levels inside the mouth using a portable gas chromatography (Oral Chroma, Abilit, Japan), and assessments of quality of life (QOL) using an SF-36 questionnaire. RESULTS: Sixty-six of the subjects were edentulous and 49 were dentulous. They were divided into two groups by VSC levels, those with oral malodor (both H2S > 112 ppb and CH3SH > 26 ppb; subjects with oral malodor, OM group; n = 7) and those without (n = 108). Our results showed that tongue coat deposit amounts and proportion of dentulous subjects were significantly higher in the OM group. Further, in an analysis of QOL, the SF-36 scores for vitality, social functioning and mental health were significantly higher in OM. CONCLUSION: We found that elderly subjects with oral malodor tended to be dentulous and had large deposits of tongue coating. However, oral malodor in the OM group subjects did not appear to cause a disadvantage in their social lives.

Regulation of the mouse preprothyrotropin-releasing hormone gene by retinoic acid receptor.

Retinoic acid (RA) has been reported to inhibit the secretion and synthesis of the pituitary TSH in vivo and in vitro. However, little is known about the influence of RA on the expression of the prepro-TRH gene. We therefore investigated whether the promoter activity of the mouse TRH gene is directly regulated by RA using a transient transfection assay into CV-1 cells. In the absence of cotransfected RA receptor (RAR), all-trans-RA did not affect the promoter activity. In contrast, the cotransfected RARalpha significantly stimulated promoter activity in the absence of ligand, and all-trans-RA reversed basal promoter activation. The cotransfected thyroid hormone receptor-beta (TRbeta), but not 9-cis-RA receptor (RXR), had an additive effect on the RAR-dependent stimulation. TR and RAR can similarly interact with the corepressor proteins, and the cotransfected nuclear receptor corepressor (N-CoR) has been demonstrated to augment the transcriptional stimulation of the TRH gene by unliganded TR. As observed with TR, the coexpression of a N-CoR variant significantly enhanced the ligand-independent stimulation by RAR. A mutant RAR (RAR403) lacking the C-terminal activation function-2 (AF-2) activation domain that was essential for ligand-induced corepressor release constitutively stimulated the promoter activity. The constitutive stimulation by RAR403 was augmented by the cotransfected N-CoR variant. A deletion analysis of the 5'-flanking region of the TRH gene revealed that the minimal promoter region for the regulation by RAR was -83 to +53, with a consensus half-site motif for the thyroid hormone response element at -57. In contrast to the strong binding of TR to the thyroid hormone response element half-site in gel retardation assays, no binding of RAR homodimer, RAR/ RXR heterodimer, or RAR/TR heterodimer was observed to the minimal promoter region. These results collectively suggest that RAR without heterodimerization with RXR and TR regulates transcription of the mouse TRH gene in cooperation with the corepressor, and that the DNA binding of RAR appeared to be unnecessary for regulation of the TRH gene promoter.

Nonsense mutations in the vpr gene of HIV-1 during in vitro virus passage and in HIV-1 carrier-derived peripheral blood mononuclear cells.

Long-term, persistent infection by HIV-1 is a prerequisite for the development of AIDS. However, little is known of the determinants required for HIV-1 to cause persistence. We have reported previously that persistent infection of a T cell line by a cytopathogenic strain of HIV-1 became increasingly likely with in vitro serial passage of the virus. DNA sequencing of the persistent strains revealed a nonsense mutation in the vpr gene in all isolates tested. Here, we report the development and use of a semi-quantitative PCR method to detect the vpr nonsense mutation within populations of virus. Our results show that vpr mutants also arise in cells during acute infection and increase progressively with serial passage of the virus. In addition, HIV-1-seropositive individuals were examined and found to carry the same vpr nonsense mutation at high frequency in virus-infected PBMC. These data are consistent with a mechanism of HIV-1 persistence in vivo and in vitro in which virus cytopathogenic potential is lost by the build up of nonsense mutations in vpr.

Demonstration of human Borna disease virus RNA in human peripheral blood mononuclear cells.

BDV naturally infects horses and sheep, and causes sporadic neurological disease. Serological evidence suggests an association of BDV, or a related virus, with specific psychiatric diseases in humans. Here, by using a nested RT-PCR technique, we demonstrate that human BDV RNA is present in the PBMC of psychiatric patients. In an examination of a total of 60 patients from 5 wards of a hospital in Japan, the detection rate differed within each ward, ranging from 8% to > 50% (37% on the average). Of particular note was the finding that the human derived BDV sequences, which included deleted forms in about 23% of the positive samples, were slightly different from those derived from horse BDV. These results suggest urgent consideration of the measures to be taken to cope with the effects of blood transfusion. In addition, the detection of a high level of BDV in the PBMC of patients will help our understanding of the pathogenesis in the disease.

FTIR spectral study of intramolecular hydrogen bonding in thromboxane A2 receptor agonist (U-46619), prostaglandin (PG)E2, PGD2, PGF2 alpha, prostacyclin receptor agonist (carbacyclin), and their related compounds in dilute CCl4 solution: structure-activity relationships.

FTIR spectra measurements and full optimization curve analysis of their spectra were done to obtain parameters of the OH and C = O stretching vibration bands for intramolecular hydrogen bondings in thromboxane (TX)A2 receptor partial agonist (CTA2), prostaglandin (PG)E2, PGD2, PGF2 alpha, prostacyclin (PGI2) receptor agonist (carbacyclin), and their related compounds in dilute CCl4 solutions. For CTA2, PGE2, PGD2, and PGF2 alpha, cyclic intramolecular hydrogen bonds involving a 15-membered ring similar to that observed for the TXA2 receptor agonist (U-46619) were found between a carboxyl group of the alpha-side chain and a 15-hydroxyl group of the omega-side chain. The arrangement of these side chains was P-shaped, and the percentage of the intramolecular hydrogen-bonded molecules with the 15-membered ring in CCl4 solution showed a high value of ca. 80% for these compounds. In addition, it was found that the cyclic intramolecular hydrogen bonds involving the 13-, 12-, and 12-membered rings in PGE2, PGD2, and PGF2 alpha, respectively, are formed between the carboxyl group of the alpha-side chain and the 11-, 9-, and 9-hydroxyl groups of a cyclopentane ring, respectively, although the percentages of the intramolecular hydrogen-bonded molecules with these membered rings are very small. It was also found that the hydrogen bond is more easily formed in the order of the 11-, 9-, and 15-hydroxyl groups. For carbacyclin, the cyclic intramolecular hydrogen bond involving the 13-membered ring was found between the carboxyl group of the alpha-side chain and the 11-hydroxyl group. The percentage of the intramolecular hydrogen-bonded molecules showed the value of 58% for carbacyclin. On the basis of information on the side-chain conformations in CCl4, we examined the structure-activity relationships for U-46619 in place of TXA2, PGE2, PGD2, PGF2 alpha, and carbacyclin in place of PGI2.