A mixed-methods study on the pharmacological management of pain in Australian and Japanese nursing homes.

BACKGROUND: Understanding how analgesics are used in different countries can inform initiatives to improve the pharmacological management of pain in nursing homes. AIMS: To compare patterns of analgesic use among Australian and Japanese nursing home residents; and explore Australian and Japanese healthcare professionals' perspectives on analgesic use. METHODS: Part one involved a cross-sectional comparison among residents from 12 nursing homes in South Australia (N = 550) in 2019 and four nursing homes in Tokyo (N = 333) in 2020. Part two involved three focus groups with Australian and Japanese healthcare professionals (N = 16) in 2023. Qualitative data were deductively content analysed using the World Health Organization six-step Guide to Good Prescribing. RESULTS: Australian and Japanese residents were similar in age (median: 89 vs 87) and sex (female: 73% vs 73%). Overall, 74% of Australian and 11% of Japanese residents used regular oral acetaminophen, non-steroidal anti-inflammatory drugs or opioids. Australian and Japanese healthcare professionals described individualising pain management and the first-line use of acetaminophen. Australian participants described their therapeutic goal was to alleviate pain and reported analgesics were often prescribed on a regular basis. Japanese participants described their therapeutic goal was to minimise impacts of pain on daily activities and reported analgesics were often prescribed for short-term durations, corresponding to episodes of pain. Japanese participants described regulations that limit opioid use for non-cancer pain in nursing homes. CONCLUSION: Analgesic use is more prevalent in Australian than Japanese nursing homes. Differences in therapeutic goals, culture, analgesic regulations and treatment durations may contribute to this apparent difference.

Consistency between Primary Uterine Corpus Malignancies and Their Corresponding Patient-Derived Xenograft Models.

Patient-derived xenograft (PDX) models retain the characteristics of tumors and are useful tools for personalized therapy and translational research. In this study, we aimed to establish PDX models for uterine corpus malignancies (UC-PDX) and analyze their similarities. Tissue fragments obtained from 92 patients with uterine corpus malignancies were transplanted subcutaneously into immunodeficient mice. Histological and immunohistochemical analyses were performed to compare tumors of patients with PDX tumors. DNA and RNA sequencing were performed to validate the genetic profile. Furthermore, the RNA in extracellular vesicles (EVs) extracted from primary and PDX tumors was analyzed. Among the 92 cases, 52 UC-PDX models were established, with a success rate of 56.5%. The success rate depended on tumor histology and staging. The pathological and immunohistochemical features of primary and PDX tumors were similar. DNA sequencing revealed similarities in gene mutations between the primary and PDX tumors. RNA sequencing showed similarities in gene expressions between primary and PDX tumors. Furthermore, the RNA profiles of the EVs obtained from primary and PDX tumors were similar. As UC-PDX retained the pathological and immunohistochemical features and gene profiles of primary tumors, they may provide a platform for developing personalized medicine and translational research.

Cancer-Specific miRNAs Extracted from Tissue-Exudative Extracellular Vesicles in Ovarian Clear Cell Carcinoma.

Ovarian clear cell carcinomas (OCCs) arise from endometriotic cysts that many women develop. Biomarkers for early OCC detection need to be identified. Extracellular vesicles have attracted attention as biomarker carriers. This study aims to identify cancer-specific miRNAs as novel OCC biomarkers using tissue-exudative extracellular vesicles (Te-EVs). Te-EVs were collected from four patients with OCC on one side and a normal ovary on the other side. Microarray analysis was performed to identify cancer-specific miRNAs in Te-EVs. Serum samples obtained before and after surgery from patients with OCC and atypical endometrial hyperplasia (AEH) (controls) were compared using real-time PCR to examine changes in the detected EV miRNA levels. Thirty-seven miRNAs were >2-fold upregulated on the OCC side compared with the normal ovarian side. We selected 17 miRNAs and created specific primers for 12 of these miRNAs. The levels of six EV miRNAs were significantly decreased in postoperative OCC serum compared to those in preoperative OCC serum. In contrast, no significant change was observed between the pre and postoperative values in the control group. We identified OCC tissue-specific miRNAs in the EVs secreted by OCC tissues. These EV miRNAs have potential for use as biomarkers for the early diagnosis and detection of OCC.

Effects of neuromuscular electrical stimulation on pulmonary alveola and cytokines in chronic obstructive pulmonary disease (COPD) and skeletal muscle atrophy model mice.

[Purpose] It has been reported that exercise affects skeletal muscle in the chronic obstructive pulmonary disease (COPD) disease model. In this study, we examined the effects of neuromuscular electrical stimulation (NMES) in skeletal muscle on alveoli and cytokines. [Materials and Methods] We used twenty wild-type mice, randomly divided into three groups: Group A: Control (non-COPD, non-amyotrophia, non-NMES), Group B: COPD, amyotrophia with NMES and Group C: COPD, amyotrophia without NMES. Among those, a group of mice with ages from 12 to 14 weeks were used to create a chronic obstructive pulmonary disease (COPD) model, a group of mice with ages from 15 to 16 weeks was used to create a disuse syndrome by hind limb suspension, and a group of mice with ages from 17 to 28 weeks (12 weeks) were used to implement NMES. In this study, we used the real-time PCR method to assess the mRNA expression levels. We also conducted morphological analysis, assessed macrophage expression level by staining (general staining and immunostaining), and employed spirometry. [Results] Our study results showed significant decreases in Interleukin-6 (IL-6) levels in the lungs and muscle RING-finger protein-1 (MuRF1) in the muscles. Moreover, the pulmonary stromal macrophage marker (F4/80) and the protease marker (MMP12) showed significantly decreased expression, while no change was observed in the morphological of the alveolar spaces (mean linear intercept). [Conclusion] On the basis of these findings, our study reveals that NMES affects cytokines and macrophages in COPD skeletal muscle atrophy.

Physical Function and Cardio-Ankle Vascular Index in Elderly Heart Failure Patients.

The number of heart failure patients is increasing rapidly in Japan because of its large elderly population. As age increases, arterial stiffness and physical dysfunction progress. This study aimed to evaluate the association between the physical function and arterial stiffness in elderly heart failure patients.This retrospective, observational study includes data from 100 heart failure patients aged ≥ 65 years who were admitted to our hospital and underwent cardiac rehabilitation. The Cardio-Ankle Vascular Index (CAVI) was measured as an indicator of arterial stiffness. Body composition was assessed by bioelectrical impedance analysis. To determine the degree of physical function, we assessed handgrip strength, five-meter walk speed (5MWS), five-repetition sit-to-stand time (5RSST) and six-minute walk distance (6MWD). Sarcopenia was defined using Asian guidelines based on physical function and body composition.Among 100 patients, 47.0% of patients had sarcopenia. After adjustments for age, sex, atrial fibrillation, and ischemic cardiomyopathy, CAVI was significantly higher in with sarcopenia patients than those without sarcopenia. Age, handgrip strength, 5MWS, 5RSST, and 6MWD were associated with CAVI, and 6MWD was as an independent determinant factor of CAVI.6MWD was recognized as an accurate physical function indicator. These findings suggested that physical function and arterial stiffness complement each other. To restore cardiac dysfunction, improving both arterial stiffness and physical function might be useful.

Effects of simplified lymph drainage on the body: in females with menopausal disorder.

[Purpose] Hormone replacement therapy has been reported to be effective for alleviating menopausal symptoms, its side effects have been a concern. Therefore, it is necessary to investigate methods that could alleviate menopausal symptoms but with fewer side effects. Few previous reports have investigated the effects of simplified, viable manual lymph drainage, particularly the effects of one-time therapy on physiologically active substances and other variables. Effects of one-time simplified lymph drainage performed at salon A were investigated in females with any type of menopausal symptoms, such as edema or a sense of fatigue. [Subjects and Methods] Before and after lymph drainage, saliva was collected to detect substances that would reveal immune function. Questionnaire surveys were also conducted before and after therapy. [Results] Cortisol and dehydroepiandrosterone levels were significantly reduced after therapy compared with those before therapy. The questionnaire survey showed a significant decrease in the visual analog scale. Also apparent were positive opinions, such as "I feel better" and "My legs feel lighter." [Conclusion] These results demonstrated the stress reduction effect of one-time simplified lymph drainage, which decreased cortisol and dehydroepiandrosterone levels. This therapy was also shown to produce positive mental and physical effects.

2-Aminoalkyl nicotinamide derivatives as pure inverse agonists of the ghrelin receptor.

New inverse agonists of the ghrelin receptor (ghrelinR) were obtained through high-throughput screening and subsequent structural modification of 2-aminoalkyl nicotinamide derivatives. The key structural feature to improve in vitro activity was the introduction of a diazabicyclo ring at the 5-position of the pyridine ring. The final product showed potent inverse agonist activity and, despite its low brain permeability, reduced food intake in both normal and obese mice. These results implied that peripheral ghrelinR activity is important for appetite control and that a peripheral ghrelinR inverse agonist could be an anti-obesity drug with reduced risk of central nervous system (CNS)-related side effects.

Orally active ghrelin receptor inverse agonists and their actions on a rat obesity model.

A series of 2-alkylamino nicotinamide analogs was prepared as orally active ghrelin receptor (ghrelinR) inverse agonists. Starting from compound 1, oral bioavailability was improved by modifying metabolically unstable sites and reducing molecular weight. Brain-permeable compound 33 and compound 24 with low brain permeability were tested in rat models of obesity; 30 mg/kg of compound 33 suppressed weight gain. PK/PD analysis revealed that the anti-obesity effect of ghrelinR inverse agonists depends on their brain concentrations.

Structural Optimization of Ghrelin Receptor Inverse Agonists to Improve Lipophilicity and Avoid Mechanism-Based CYP3A4 Inactivation.

Structural optimization of 2-aminonicotinamide derivatives as ghrelin receptor inverse agonists is reported. So as to avoid mechanism-based inactivation (MBI) of CYP3A4, 1,3-benzodioxol ring of the lead compound was modified. Improvement of the main activity and lipophilicity was achieved simultaneously, leading to compound 18a, which showed high lipophilic ligand efficiency (LLE) and low MBI activity.

Long-term Effect of Ubiquinol on Exercise Capacity and the Oxidative Stress Regulation System in SAMP1 Mice.

[Purpose] This study examined how exercise capacity and the oxidative stress regulation system are affected by different amounts of dietary Ubiquinol (reduced form of coenzyme Q10, H2CoQ10: QH) over the long term. [Subjects and Methods] Twenty-three senescence-accelerated mouse P1 (SAMP1) mice were randomly divided into two groups: one consuming a relatively high amount of QH (300 mg/kg; Group A) and the other a relatively low amount (30 mg/kg, Group B). Food and tap water were provided ad libitum. Both groups were made to run on a treadmill until exhaustion, and total running duration was measured. For the oxidative stress regulation system, the d-ROM test value (degree of oxidative stress) and BAP test value (antioxidant potential) were measured in a resting state, and then the BAP/d-ROM ratio (B/R ratio) was calculated. The values of plasma QH and plasma ubiquinone (plasma oxidized form of CoQ10) were also measured, and the reduced ratio was calculated. Measurements were taken 3 times: at the start of the study when the animals were 39 weeks old (baseline), after consumption of QH for 7 months (7 mo), and after consumption of QH for 10 months (10 mo). [Results] The senescence score at 10 mo was significantly lower in Group A. Comparison of the mean percentage change in running time showed a difference of 15.1% between the 2 groups. At 10 mo, the d-ROM test value was significantly increased and the B/R ratio was significantly decreased in Group B. Significant increases in the plasma QH value and reduced ratio were seen in Group A. [Conclusion] Group A showed a greater decrease in the d-ROM test and increase in the reduced ratio than Group B. Thus, a dose-dependent effect of QH consumption was demonstrated.

Oncologic Outcomes of Patients with Early-Stage Cervical Cancer after Minimally Invasive Radical Hysterectomy and Sentinel Lymph Node Biopsy.

Background: The sentinel lymph node is the first node that cancer cells reach when migrating from the primary site. However, oncological outcomes after sentinel lymph node biopsy (SNB) have not been reported for cervical cancer. In this study, oncological outcomes were compared between patients receiving SNB and pelvic lymphadenectomy (PLD) for early-stage cervical cancer. Methods: One hundred and four patients with clinical stage 1A2, 1B1, and 2A1 cervical cancer were included in this study. All patients underwent laparoscopic or robot-assisted radical hysterectomy with SNB or PLD. Fifty-two patients with tumors ≤2 cm underwent SNB. Disease-free survival (DFS) and overall survival (OS) were compared between the groups. Results: The median (interquartile range) tumor size was 12 (7-20) mm in the SNB group and 20 (13-25) mm in the PLD group. Lymph node metastasis occurred in one patient in the SNB group and in nine patients in the PLD group. The median follow-up periods were 42 (24-60) and 82 (19-101) months in the SNB group and PLD group, respectively. The 3-year DFS rates were 100% in SNB and 91.5% in PLD. The 3-year OS was 100% in both groups. Conclusions: SNB was sufficient in cervical cancer patients with tumors ≤2 cm, suggesting that PLD might not be necessary for these patients.

Creation and Validation of Patient-Derived Cancer Model Using Peritoneal and Pleural Effusion in Patients with Advanced Ovarian Cancer: An Early Experience.

Background: The application of personalized cancer treatment based on genetic information and surgical samples has begun in the field of cancer medicine. However, a biopsy may be painful for patients with advanced diseases that do not qualify for surgical resection. Patient-derived xenografts (PDXs) are cancer models in which patient samples are transplanted into immunodeficient mice. PDXs are expected to be useful for personalized medicine. The aim of this study was to establish a PDX from body fluid (PDX-BF), such as peritoneal and pleural effusion samples, to provide personalized medicine without surgery. Methods: PDXs-BF were created from patients with ovarian cancer who had positive cytology findings based on peritoneal and pleural effusion samples. PDXs were also prepared from each primary tumor. The pathological findings based on immunohistochemistry were compared between the primary tumor, PDX, and PDX-BF. Further, genomic profiles and gene expression were evaluated using DNA and RNA sequencing to compare primary tumors, PDXs, and PDX-BF. Results: Among the 15 patients, PDX-BF was established for 8 patients (5 high-grade serous carcinoma, 1 carcinosarcoma, 1 low-grade serous carcinoma, and 1 clear cell carcinoma); the success rate was 53%. Histologically, PDXs-BF have features similar to those of primary tumors and PDXs. In particular, PDXs-BF had similar gene mutations and expression patterns to primary tumors and PDXs. Conclusions: PDX-BF reproduced primary tumors in terms of pathological features and genomic profiles, including gene mutation and expression. Thus, PDX-BF may be a potential alternative to surgical resection for patients with advanced disease.

Discovery of novel series of 6-benzyl substituted 4-aminocarbonyl-1,4-diazepane-2,5-diones as human chymase inhibitors using structure-based drug design.

A novel series of 6-benzyl substituted 4-aminocarbonyl-1,4-diazepane-2,5-diones were explored as human chymase inhibitors using structure-based drug design according to the X-ray cocrystal structure of chymase and compound 1. The optimization focused on the prime site led to the attainment of compounds that showed potent inhibitory activity, and among them, 18R shows a novel interaction mode.

Effects of combined training with breathing resistance and sustained physical exertion to improve endurance capacity and respiratory muscle function in healthy young adults.

[Purpose] In this study, combined training with breathing resistance and sustained physical exertion was carried out to evaluate its physiological effects and its effect on improve endurance capacity. [Subjects and Methods] The subjects were nine healthy adults (mean age 20.4, SD ± 1.7 years). The combined training group (n = 5) carried out 6 weeks of combined training using a cycle ergometer, with exercise load tests and respiratory function tests performed before and after the training. The results of the training were compared to a control group (n = 4) that only performed the cycling exercise without the combined training with breathing resistance. [Results] In the combined training group, ventilatory threshold, maximal load of the cycle ergometer in exercise load tests, and maximal voluntary ventilation increased after training. These increases after training were all significant, but none of these variables changed significantly in the control group. [Conclusion] The results imply that in comparison to conventional training methods, combined training with breathing resistance and sustained physical exertion is beneficial for increasing endurance capacity and respiratory muscle function. This result provides important information regarding the effects of the new training method for improving endurance capacity.

Changes in chronic disease medications after admission to a Geriatric Health Services Facility: A multi-center prospective cohort study.

Older adults often receive polypharmacy, including some medications for chronic diseases. Nutritional management after admission to a nursing home may enable to deprescribe some chronic disease medications. This study aimed to investigate the status of deprescribing of chronic disease medications among nursing home residents, and to assess the appropriateness based on changes of laboratory test values and nutritional status. A multi-center prospective cohort study was conducted in 6 Geriatric Health Services Facilities, a major type of nursing homes in Japan. Newly admitted residents aged ≥ 65 years who took ≥1 medication for hypertension, diabetes, or dyslipidemia at admission were recruited. Participants who stayed for 3 months were included in the analysis. Medications at admission and 3 months after admission and situations for deprescribing were investigated. Changes in body mass index, blood pressure, laboratory tests (e.g., cholesterol and hemoglobin A1c levels), energy intake, and International Classification of Functioning, Disability and Health staging were evaluated. Sixty-nine participants (68% female, 62% aged ≥ 85 years) were included. At admission, 60 participants had medications for hypertension, 29 for dyslipidemia, and 13 for diabetes. Those receiving lipid-modifying drugs (mainly statins) decreased from 29 to 21 (72%; P = .008), since their cholesterol levels was within the normal range or was low at admission, and they had no history of cardiovascular events. However, there were no statistically significant changes in the frequencies of antihypertensive drugs (60 to 55; 92%; P = .063) or antidiabetic drugs (13 to 12; 92%; P = 1.000). During the 3-month observation, body mass index and diastolic blood pressure decreased, while energy intake and serum albumin level increased. Nutritional management after admission to a ROKEN may facilitate appropriate deprescribing of lipid-modifying drugs, by offseting the effects of discontinuation of these drugs.

Lymphatic Complications Following Sentinel Node Biopsy or Pelvic Lymphadenectomy for Endometrial Cancer.

Sentinel node biopsy (SNB) is performed worldwide in patients with endometrial cancer (EC). The aim of this study was to evaluate and compare the occurrence rate of lymphatic complications between SNB and pelvic lymphadenectomy (LND) for EC. The medical records of women who underwent SNB or pelvic LND for EC between September 2012 and April 2022 were assessed. A total of 388 patients were enrolled in the current study. Among them, 201 patients underwent SNB and 187 patients underwent pelvic LND. The occurrence rates of lower-extremity lymphedema (LEL) and pelvic lymphocele (PL) were compared between the patients who underwent SNB and those who underwent pelvic LND. The SNB group had a significantly lower occurrence rate of lower-extremity LEL than the pelvic LND group (2.0% vs. 21.3%, p < 0.01). There were no patients who had PL in the SNB group; however, 4 (2.1%) patients in the pelvic LND group had PL. The occurrence rates of lower-extremity LEL and PL were significantly lower in patients who underwent SNB than those who underwent pelvic LND. SNB for EC has a lower risk of lymphatic complications compared to systemic LND.

Triple repeated fetal congenital heart disease linked to PLD1 mutation: a case report.

BACKGROUND: Congenital heart disease occurs in approximately 1 in 100 cases. Although sibling occurrence is high (3-9%), the causative genes for this disease are still being elucidated. PLD1 (Phospholipase D1) is a recently discovered gene; however, few case reports have been published on it. In this report, we describe a case of triplicate fetal congenital heart disease that was diagnosed as a PDL1 mutation. Our objective is to explore the clinical manifestations of PLD1 mutations in this particular case. CASE PRESENTATION: A 32-year-old Japanese woman (gravida, para 0) was introduced since fetus four chamber view was not clear and was diagnosed with ductus arteriosus-dependent left ventricular single ventricle and pulmonary atresia at 21 weeks and 1 day of gestation during her first pregnancy. Artificial abortion using Gemeprost was performed at 21 weeks and 5 days of gestation. The second pregnancy was diagnosed as pulmonary atresia with intact ventricular septum with cardiomegaly, a cardiothoracic area ratio of more than 35%, and a circulatory shunt at 13 weeks and 3 days of gestation. Subsequently, intrauterine fetal death was confirmed at 14 weeks and 3 days of gestation. Regarding the third pregnancy, fetal ultrasonography at 11 weeks and 5 days of gestation showed mild fetal hydrops and moderate tricuspid valve regurgitation. At 16 weeks and 5 days of gestation, the fetus was suspected to have a left ventricular-type single ventricle, trace right ventricle, pulmonary atresia with intact ventricular septum, or cardiomyopathy. Cardiac function gradually declined at 26 weeks of gestation, and intrauterine fetal death was confirmed at 27 weeks and 5 days of gestation. The fourth pregnancy resulted in a normal heart with good progression and no abnormal baby. We submitted the first and second fetuses' umbilical cord, third fetus' placenta, and the fourth fetus' blood to genetic testing using whole exome analysis with next generation sequencing. Genetic analysis identified hemizygous PLD1 mutations in the first, second, and third fetuses. The fourth fetus was heterozygous. In addition, the parents were heterozygous for PLD1. This case is based on three consecutive cases of homozygosity for the PLD1 gene in the sibling cases and the fetuses with recurrent right ventricular valve dysplasia. This will elucidate the cause of recurrent congenital heart disease and intrauterine fetal death and may serve as an indicator for screening the next fetus. To date, homozygous mutations in PLD1 that repeat three times in a row are not reported, only up to two times. The novelty of this report is that it was repeated three times, followed by a heterozygous live birth. CONCLUSIONS: This report is consistent with previous reports that mutations in PLD1 cause right ventricular valve dysplasia. However, there have been few case reports of PLD1 mutations, and we hope that this report will contribute to elucidate the causes of congenital heart disease, especially right ventricular valve dysplasia, and that the accumulation of such information will provide more detailed information on PLD1 mutations in heart disease.

Pelvic Abscess after Cesarean Section Treated with Laparoscopic Drainage.

Cesarean section (CS), the rate of which is increasing worldwide, may be associated with complications. Although pelvic abscess after CS is rare, it is difficult to treat. We herein report two cases of pelvic abscess treated laparoscopically after CS. The abscesses of the patients were located in the pouch of Douglas and the uterine scar after CS, respectively. Several days after CS, the patients presented with lower abdominal pain and fever. Laparoscopic drainage was performed because imaging revealed a pelvic abscess that was not amenable to drainage through interventional radiology. The patients recovered from infection and were discharged four days after drainage.

Use of psychotropic drugs and drugs with anticholinergic properties among residents with dementia in intermediate care facilities for older adults in Japan: a cohort study.

OBJECTIVES: To evaluate the prescription and discontinuation of psychotropic drugs (PD) and drugs with anticholinergic properties (DAP) in residents with dementia admitted to Roken, a major type of long-term care facility in Japan. DESIGN: Cohort study. SETTING: A nationwide questionnaire survey across 3598 Roken in Japan in 2015 (up to five randomly selected residents per facility). PARTICIPANTS: This study included 1201 residents from 343 Roken (response rate: 10%). We determined the presence and severity of dementia using a nationally standardised measure. PRIMARY AND SECONDARY OUTCOME MEASURES: Prescriptions of PD and DAP at admission and 2 months after admission were evaluated. Multivariable logistic regression was used to evaluate the associations of residents' baseline characteristics with prescriptions or discontinuation. RESULTS: Prescription rates decreased for antidementia drugs (19.4% to 13.0%), hypnotics (25.1% to 22.6%) and anxiolytics (12.3% to 10.7%), whereas those for other PD, such as antipsychotics (13.2% to 13.6%), antidepressants (7.4% to 6.7%), antiepileptic drugs (7.1% to 7.8%) and DAP (35.2% to 36.6%) did not statistically significantly decrease. Some factors were associated with the prescriptions, for example, for antipsychotics, older age (≥85 years) (adjusted OR (aOR), 0.60; 95% CI 0.43 to 0.85) and being bedridden (aOR 0.67; 95% CI 0.47 to 0.97) were associated with a lower use of antipsychotics, whereas severe dementia was associated with a higher use of antipsychotics (aOR 3.26; 95% CI 2.26 to 4.70). At an individual level, a quarter of residents prescribed PD or DAP at admission had discontinued at least one PD or DAP, respectively, 2 months after admission. Antidementia drug use in severe dementia (aOR 1.86; 95% CI 1.04 to 3.31) and PD use in older age (aOR 1.61; 95% CI 1.00 to 2.60; in residents with disabling dementia) were associated with discontinuation. CONCLUSIONS: There is possible scope for deprescribing PD and DAP in Roken residents with dementia to mitigate the risks of adverse events.

Functionalized congeners of P2Y1 receptor antagonists: 2-alkynyl (N)-methanocarba 2'-deoxyadenosine 3',5'-bisphosphate analogues and conjugation to a polyamidoamine (PAMAM) dendrimer carrier.

The P2Y(1) receptor is a prothrombotic G protein-coupled receptor (GPCR) activated by ADP. Preference for the North (N) ring conformation of the ribose moiety of adenine nucleotide 3',5'-bisphosphate antagonists of the P2Y(1) receptor was established by using a ring-constrained methanocarba (a bicyclo[3.1.0]hexane) ring as a ribose substitute. A series of covalently linkable N(6)-methyl-(N)-methanocarba-2'-deoxyadenosine-3',5'-bisphosphates containing extended 2-alkynyl chains was designed, and binding affinity at the human (h) P2Y(1) receptor determined. The chain of these functionalized congeners contained hydrophilic moieties, a reactive substituent, or biotin, linked via an amide. Variation of the chain length and position of an intermediate amide group revealed high affinity of carboxylic congener 8 (K(i) 23 nM) and extended amine congener 15 (K(i) 132 nM), both having a 2-(1-pentynoyl) group. A biotin conjugate 18 containing an extended epsilon-aminocaproyl spacer chain exhibited higher affinity than a shorter biotinylated analogue. Alternatively, click coupling of terminal alkynes of homologous 2-dialkynyl nucleotide derivatives to alkyl azido groups produced triazole derivatives that bound to the P2Y(1) receptor following deprotection of the bisphosphate groups. The preservation of receptor affinity of the functionalized congeners was consistent with new P2Y(1) receptor modeling and ligand docking. Attempted P2Y(1) antagonist conjugation to PAMAM dendrimer carriers by amide formation or palladium-catalyzed reaction between an alkyne on the dendrimer and a 2-iodopurine-derivatized nucleotide was unsuccessful. A dialkynyl intermediate containing the chain length favored in receptor binding was conjugated to an azide-derivatized dendrimer, and the conjugate inhibited ADP-promoted human platelet aggregation. This is the first example of attaching a strategically functionalized P2Y receptor antagonist to a PAMAM dendrimer to produce a multivalent conjugate exhibiting a desired biological effect, i.e., antithrombotic action.