[Feasibility and safety of closing large left atrial appendage using the LAmbre device].

Objective: To evaluate the feasibility and safety of the LAmbre occluder for large-diameter left atrial appendage occlusion. Methods: This study was a retrospective cohort study. Patients with large orifice of the left atrial appendage (≥31 mm) and occlusion with the LAmbre device in the Arrhythmia Center of Ningbo First Hospital were included from June 2018 to March 2020. Baseline data were collected and major perioperative complications of left atrial appendage occlusion (including death, stroke, instrumental embolism, cardiac tamponade, and major bleeding events) were recorded. Patients were followed up 45 days, 6 months and 12 months after surgery. The shunt and device-related thrombosis were recorded by esophageal cardiac ultrasound or pulmonary vein CT, and the occurrence of postoperative thromboembolism, bleeding events, death and other serious adverse events were recorded. Results: The average age and left atrial appendage ostial dimension of 32 patients (37.5% women) included in this research were (70.4±8.4) years old and (34.4±2.9) mm. The LAmbre device was successfully implanted in 31(96.9%) patients. No major complications occurred during the perioperative period. During the 12-month follow-up, pericardial tamponade occurred in 1(3.2%) patient and was recovered after treatment. There was no occluder edge shunt>5 mm in patients followed up by esophageal echocardiography. No significant peri-device leak, device-related thrombus, thromboembolism or death event has occurred. Conclusion: The LAmbre occluder may be feasible and safe for large-diameter left atrial appendage occlusion.

Hydroxytyrosol suppresses LPS-induced intrahepatic inflammatory responses via inhibition of ERK signaling pathway activation in acute liver injury.

OBJECTIVE: Acute liver injury (ALI) leads to inflammatory response and tissue damage. Inflammatory activation of infiltrative macrophages plays a critical role in liver histology destruction and dysfunction. Hydroxytyrosol (3,4-dihydroxyphenil-ethanol, HT), one of the polyphenols extracted from extra virgin olive oil, currently acts as a treatment for neuroinflammatory responses, but its effect on ALI is elusive. The present study aims to examine the mechanism of HT in macrophages inflammation and evaluate treatment effect of HT on ALI. MATERIALS AND METHODS: In vitro, the expressions of type M1/M2 macrophages biomarkers (CD11c/CD206) and cytokines (TNF-α, IL-1ß, IL-6, IL-10, IL-4) following lipopolysaccharide (LPS) stimulation and HT administration were detected using immunofluorescence, quantitative real-time polymerase chain reaction (qRT-PCR), and enzyme-linked immunosorbent assay (ELISA). Mechanically, HT was used to treat cells and phosphorylation level of extracellular-signal-regulated kinase 1/2 (ERK1/2) protein in cells was analyzed using Western blotting. In murine acute liver injury, inflammatory cytokines and liver injury degree were exhibited by qRT-PCR, IHC and HE staining. Furthermore, hepatic function was exhibited via hepatic metabolic enzymes (ALT/AST) and total bilirubin (TBil) in serum. RESULTS: It was demonstrated that HT treatment attenuated M1 macrophages and increased M2 macrophages after LPS stimulation. Furthermore, the pro-inflammatory cytokine level was descended, while an-inflammatory cytokine was increased via HT suppressing ERK pathway in macrophages. In vivo, HT reduced inflammatory level and mitigated hepatic histological injury, thus ameliorating liver function after acute liver injury. CONCLUSIONS: HT exerts a hepatoprotective and anti-inflammation effect on acute liver injury, which restrains inflammation by inhibiting ERK pathway and regulating macrophages polarization. Moreover, HT prevents liver tissues from inflammatory injury. Therefore, HT serves as a potential implication to treat ALI through modulating inflammation of macrophages.

Ultrastructure of intestinal mucosa in diarrhea-predominant irritable bowel syndrome.

OBJECTIVES: Impaired intestinal barrier function has been demonstrated in the pathophysiology of diarrhea-predominant irritable bowel syndrome (IBS-D). This study aimed to describe the intestinal ultrastructural findings in the intestinal mucosal layer of IBS-D patients. METHODS: In total, 10 healthy controls and 10 IBS-D patients were analyzed in this study. The mucosa of each patient's rectosigmoid colon was first assessed by confocal laser endomicroscopy (CLE); next, biopsied specimens of these sites were obtained. Intestinal tissues of IBS-D patients and healthy volunteers were examined to observe cellular changes by transmission electron microscopy (TEM). RESULTS: CLE showed no visible epithelial damage or inflammatory changes in the colonic mucosa of IBS-D compared with healthy volunteers. On transmission electron microscopic examination, patients with IBS-D displayed a larger apical intercellular distance with a higher proportion of dilated (>20 nm) intercellular junctional complexes, which was indicative of impaired mucosal integrity. In addition, microvillus exfoliation, extracellular vesicle as well as increased presence of multivesicular bodies were visible in IBS-D patients. Single epithelial cells appeared necrotic, as characterized by cytoplasmic vacuolization, cytoplasmic swelling, and presence of autolysosome. A significant association between bowel habit, frequency of abdominal pain, and enlarged intercellular distance was found. CONCLUSION: This study showed ultrastructural alterations in the architecture of intestinal epithelial cells and intercellular junctional complexes in IBS-D patients, potentially representing a pathophysiological mechanism in IBS-D.

Brain-derived neurotrophic factor modulates intestinal barrier by inhibiting intestinal epithelial cells apoptosis in mice.

We aimed to investigate the effects of brain-derived neurotrophic factor (BDNF) on apoptosis of intestinal epithelial cells (IECs) and alterations of intestinal barrier integrity using BDNF knock-out mice model. Colonic tissues from BDNF(+/+) mice and BDNF(+/-) mice were prepared for this study. The integrity of colonic mucosa was evaluated by measuring trans-mucosa electrical resistance and tissue conductance in Ussing chamber. The colonic epithelial structure was analyzed by transmission electron microscopy. Apoptosis involvement was determined with TUNEL staining, active caspase-3 immunostaining and Western blotting for the protein expression of active caspase-3, Bax and Bcl-2. The expression levels and distribution of tight junction proteins were evaluated by immunohistochemistry or Western blots. Compared with BDNF(+/+) mice, BDNF(+/-) mice displayed impaired integrity and ultrastructure alterations in their colonic mucosa, which was characterized by diminished microvilli, mitochondrial swelling and epithelial cells apoptosis. Altered intestinal barrier function was linked to excessive apoptosis of IECs demonstrated by the higher proportion of TUNEL-positive apoptotic cells and enhanced caspase activities in BDNF(+/-) mice. Increased expression of Bax and claudin-2 proteins and reduced Bcl-2 and tight junction proteins (occludin, ZO-1 and claudin-1) expression were also detected in the colonic mucosa of BDNF(+/-) mice. BDNF may play a role in the maintenance of intestinal barrier integrity via its anti-apoptotic properties.

[The difference expression and diagnostic value of RPL5 in papillary thyroid carcinoma of children and adults].

Objective: To study the difference expression and diagnostic value of ribosomal protein L5 (RPL5) in papillary thyroid carcinoma (PTC) of children and adults. Methods: Realtime-PCR was performed to detect the expression of RPL5 in 22 PTC tissues and 13 pericarcinous tissues. Receiver operating characteristic (ROC) curve and Youden's index were used to evaluate the diagnostic value of RPL5 in PTC of children and adults. Results: The expression of RPL5 in PTC tissues was higher than in pericarcinous tissues. The area under curve (AUC) was 0.820 (P=0.001), and Youden's index was 0.568. The expression of RPL5 in PTC of adults was higher than children (P<0.05). The AUC and Youden's index were respectively 0.721 (P=0.069) and 0.414 in children, whereas being respectively 0.896 (P=0.0005) and 0.709 in adults. RPL5 in diagnosis of PTC of adults was better than CK19, Galectin-3 and TPO, which are commonly used for the pathologic diagnosis of PTC. Conclusion: The expression of RPL5 in PTC is higher than pericarcinous tissues, and its expression in PTC of adults is higher than children. Furthermore, PTC is a potential indicator for diagnosis of PTC.

[The study on the inhibitive effects of recombinant parathyroid hormone (1-34) on osteolysis in a murine calvarial model induced by wear particles].

Objective: To investigate the effect of different doses of recombinant parathyroid hormone (PTH) (1-34) on osteolysis in a murine calvarial model. Methods: In total, 48 adult male C57BL/J6 mice were randomly divided into four groups: the sham group, the vehicle group, the low dose-, and high dose PTH group (n=12 each group). Mice in the PTH groups were treated with local injection of recombinant PTH at 30 or 60 µg·kg-1·d-1, intermittent injection 3 times per week for two weeks. Mice in the sham and vehicle groups received local injection of saline daily. Two weeks after surgery, calvarial tissue and peripheral blood were harvested for further analysis. Osteolysis was assessed by micro-computed tomography. The mRNA and protein expression of osteoprotegerin (OPG) and receptor activator for nuclear factor-κB Ligand (RANKL) of calvarial tissue and peripheral blood were tested by real-time PCR and ELISA, respectively. Results: Compared with the vehicle group, PTH treatment significantly inhibited the severity of osteolysis and improved the bone volume. Real time-PCR and ELISA showed that PTH significantly increased the mRNA and protein expression of OPG and reduced the RANKL/OPG ratio. Conclusion: These findings suggest that local application of PTH could effectively inhibit wear-particle-induced-osteolysis in a murine calvarial model.

Screening for genes that are differentially-expressed between gastric cancer cells and gastric tumor sphere cells using the gene chip technique.

The purpose of this study was to screen for genes that were differentially expressed between a human gastric carcinoma cell line (HGC-27) and their tumor spheres, using the gene chip technique. The HGC-27 cells and tumor sphere cells were cultured in vitro in a sterile environment. Total RNA was extracted from both samples and purified using a standard TRIzol reagent. Total RNA was then hybridized onto a GeneChip, according to the standard protocols provided by the manufacturers of the GeneChip IVT Express Kit. The resulting fluorescence signals were analyzed and displayed using the Cluster and Treeview software programs. Under the criteria for significant differential expression (≥2-fold difference), 610 up- and 1135 down-regulated genes were identified in tumor sphere cells, compared to HCG-27 cells. These genes were involved in cell growth, signal transduction, tumorigenesis, and many other functional aspects of tumor cells. In conclusion, a number of genes were differentially expressed in tumor sphere cells compared to HCG-27 cells. In addition, we identified a close correlation between tumor sphere cells and tumorigenesis.

Linear dependence of the water proton transverse relaxation rate on the shear modulus of hydrogels.

It is found that hydrogelation of peptides enhances the transverse relaxation rate R2 of water protons but has no effect on the longitudinal relaxation rate R1 and the diffusion coefficient D. The magnitude of water proton R2 enhancement increases linearly with the shear modulus G of hydrogels.

Increased cancer risk in patients with haemophilia A: a nationwide population-based 14-year study in Taiwan.

Haemostasis is associated with the development and dissemination of cancer. Whether cancer incidence is increased in haemophiliacs remains uncertain; thus, we aimed to further examine this issue. By using data from the National Health Insurance Research Database in Taiwan, we obtained a cohort of 683 patients with haemophilia A, and compared the incidence rate ratio (IRR) of cancer in this cohort with an age- and sex-matched control of 6830 patients. The log-rank test was used to compare Kaplan-Meier curve of the cumulative cancer incidence between two cohorts. Cox regressions were used to identify independent risk factors of cancer in the study patients. The cancer incidence of patients with haemophilia A was significantly higher compared to the control group (IRR 1.95, 95% CI 1.18-3.09, P = 0.008) during the 14-year follow-up period. The non-lymphoma and non-liver cancer incidence in the haemophilia A cohort remained higher than that of the matched control (P = 0.050 by the log-rank test). The multivariate Cox proportional hazards analysis indicated that age (per year, HR 1.09, 95% CI 1.06-1.12, P < 0.001) was the only significant risk factor for cancer development in haemophilia patients. Patients with haemophilia A had higher cancer incidence than the age- and sex-matched patients, especially for the elderly. With increasing life expectancy for haemophiliacs, physicians should be aware of their cancer development.

Meta-analysis of confocal laser endomicroscopy for the detection of colorectal neoplasia.

AIM: Confocal laser endomicroscopy (CLE) is a recently developed technique used to image colorectal neoplasia. Trials have shown varied results when it is compared with conventional colonoscopy. A meta-analysis was performed to determine the diagnostic accuracy of CLE in the detection of colorectal neoplasia. METHOD: A search was performed for studies assessing the accuracy of CLE in colorectal neoplasia. Studies comparing CLE diagnostic accuracy with conventional endoscopy in the detection of colorectal neoplasia were included. Exclusion criteria included case reports or case series, reviews, duplicate reports or insufficient data in the paper. Seventy-eight titles came up in the initial search and six studies were selected. These were subjected to a meta-analysis. In all, 284 patients with 1030 lesions were included. Each patient underwent conventional colonoscopy and CLE. Per-lesion sensitivity and specificity with 95% CI were calculated. RESULTS: In the individual studies, the sensitivity ranged from 33.3% to 100% and specificity from 71.6% to 99.4%. The weighted and total pooled result (random effects model) for sensitivity was 81% (95% CI 77-85) and for specificity was 88% (95% CI 85-90). The area under the weighted symmetric summary receiver operating curve was 0.9186. In the endoscope-based CLE subgroup, the sensitivity was 82% (95% CI 69-91) and specificity was 94% (95% CI 91-96). In the probe-based CLE subgroup, the sensitivity was 81% (95% CI 76-85) and the specificity was 75% (95% CI 69-81). CONCLUSION: CLE, using either the endoscope-based CLE or probe-based CLE technique, has high sensitivity and specificity. It could therefore be considered as an alternative endoscopic method to distinguish neoplastic from non-neoplastic lesions.

Unusual coexistence of sinonasal myeloid sarcoma and acute fulminant invasive fungal sinusitis: a diagnostic dilemma.

OBJECTIVE: We report a rare case of concurrent myeloid sarcoma and acute fulminant invasive fungal sinusitis in a patient with relapsed acute myeloid leukaemia. CASE REPORT: A 73-year-old man was diagnosed with acute myeloid leukaemia and developed relapse one year later. After two courses of azacytidine, he began suffering from a dull pain in the left temporal and orbital regions. Sinus computed tomography showed a localised lesion in the left ethmoid sinus, which rapidly progressed to an extensive intracranial mass within one month. Surgical debridement was performed, and histopathological analysis revealed the coexistence of myeloid sarcoma and acute fulminant invasive fungal sinusitis. The patient responded well to prompt surgical debridement, antifungal medication and radiotherapy. CONCLUSION: Coexistence of sinonasal myeloid sarcoma and acute fulminant invasive fungal sinusitis poses an urgent diagnostic and management challenge to clinicians. Timely recognition of this rare comorbid condition is warranted as application of appropriate treatment can save lives.

How to predict the outcome in mature T and NK cell lymphoma by currently used prognostic models?

To select an appropriate prognostic model in the treatment of mature T- and natural killer (NK) -cell lymphoma (peripheral T-cell lymphoma (PTCL) and NK-/T-cell lymphoma (NKTCL)) is crucial. This study investigated the usefulness of Ann Arbor staging classification International prognostic index (IPI), prognostic index for T-cell lymphoma (PIT) and International peripheral T-cell lymphoma Project score (IPTCLP). Between 2000 and 2009, 176 patients (122 males) with PTCL and NKTCL were diagnosed and treated from a single institute in Taiwan. The correlation between complete response (CR) rate, 3-year overall survival (OS), early mortality rate and four prognostic models was analyzed. Thirty-one patients received hematopoietic stem cell transplantation (HSCT) and were analyzed separately. Three-year OS rate was 34.7%, and anaplastic large-cell lymphoma harbored better outcome than others. IPI score had the lowest Akaike information criterion value (1081.197) and was the best score in predicting OS and early mortality (P=0.009). Ann Arbor stage classification can predict CR rate more precisely (P=0.006). OS was significantly better in patients who received HSCT, even in patients with unfavorable features compared with chemotherapy alone. All prognostic models were useful to evaluate the outcome of patients with PTCL and NKTCL but IPI score did best in predicting OS in PTCL and PIT score in NKTCL. This study also supported the role of HSCT in patients with high-risk or refractory PTCL or NKTCL.

BCLAF1 is a radiation-induced H2AX-interacting partner involved in γH2AX-mediated regulation of apoptosis and DNA repair.

H2AX, a histone H2A variant, has a key role in the cellular response to DNA double-strand breaks (DSBs). H2AX senses DSBs through rapid serine 139 phosphorylation, concurrently leading to the formation of phospho-(γ)H2AX foci with various proteins. However, in the cells with different sensitivity to ionizing radiation (IR)-induced DSBs, still incomplete are those specific proteins selectively recruited by γH2AX to decide different cell fates. Because the abundance of γH2AX indicates the extent of DSBs, we first identified IR-induced dose-dependent H2AX-interacting partners and found that Bcl-2-associated transcription factor 1 (BCLAF1/Btf) showed enhanced association with γH2AX only under high-dose radiation. In acutely irradiated cells, BCLAF1 promoted apoptosis of irreparable cells through disturbing p21-mediated inhibition of Caspase/cyclin E-dependent, mitochondrial-mediated pathways. Meanwhile, BCLAF1 co-localized with γH2AX foci in nuclei and stabilized the Ku70/DNA-PKcs complex therein, facilitating non-homologous end joining (NHEJ)-based DSB repair in surviving cells. In tumor cells, BCLAF1 was intrinsically suppressed, leading to formation of anti-apoptotic Ku70-Bax complexes and disruption of Ku70/DNA-PKcs complexes, all of which contribute to tumor-associated apoptotic resistance and cell survival with defective NHEJ DNA repair. For the first time, our studies reveal that, based on the extent of DNA damage, BCLAF1 is involved in the γH2AX-mediated regulation of apoptosis and DNA repair, and is a γH2AX-interacting tumor suppressor.

Prior exercise training alleviates the lung inflammation induced by subsequent exposure to environmental cigarette smoke.

AIM: Environmental cigarette smoke (CS) contains many compounds that are harmful to the respiratory system and lead to chronic lung inflammation and other lung diseases. Exercise training is known to confer protection against diseases with chronic inflammation by reducing inflammatory response in human or experimental animals. In this study, we investigated the preventive effect of exercise training against lung inflammation induced by environmental CS. METHODS AND RESULTS: In this study, two groups of mice received air exposure with (the exercise group) or without (the control group) exercise training for 8 weeks and another two groups received air exposure for the first 4 weeks and CS exposure for the following 4 weeks with (the exercise+CS group) or without (the CS group) exercise training for 8 weeks. As compared with lung tissues of control and exercise groups, those of the CS group showed significantly increased bronchoalveolar-capillary permeability, inflammatory cell infiltration, epithelial thickening, expression of proliferating cell nuclear antigen, mucin 2, cytokines, chemokines, adhesion molecules and activation of NF-κB. These CS-induced pathophysiologic consequences were largely prevented in the exercise + CS group. CONCLUSION: Collectively, prior exercise training may protect against lung inflammation induced by environmental CS in mice by attenuating the activation of NF-κB and the production of inflammatory mediators.

Cost-effectiveness of postremission intensive therapy in patients with acute leukemia.

BACKGROUND: We assessed the cost-effectiveness of high-dose arabinoside (HiDAC)-based and allogeneic stem-cell transplantation (alloSCT)-based therapy in patients with acute leukemia. PATIENTS AND METHODS: We analyzed the outcome, cost and cost-effectiveness of 106 patients treated from January 1994 to January 2002 [94 acute myelogenous leukemia (AML)/12 acute lymphoblastic leukemia (ALL)]. Forty-two young patients at either intermediate or unknown cytogenetic risk received postremission intensive therapy (24 HiDAC-based/18 alloSCT-based therapy). RESULTS: After a median follow-up of 50 months, the estimated 7-year overall survival for the HiDAC-based group showed a tendency to be higher than the alloSCT-based group (48% versus 28%, P = 0.1452). The HiDAC-based group spent a significantly lower total cost ($US51,857 versus 75,474, P = 0.004) than the alloSCT-based group. Cost-effectiveness analysis showed that the mean cost per year of life saved for the HiDAC-based group is considerably less expensive than the alloSCT-based group ($US11,224 versus 21,564). The reduced total cost for the HiDAC-based group originated from lower cost in room fees, medication, laboratory and procedure, but not in blood transfusion and professional manpower fees. CONCLUSION: For the postremission therapy in young AML patients at either intermediate or unknown cytogenetic risk, cost-effectiveness of HiDAC-based therapy compares favorably with that of alloSCT-based therapy, which deserves further clinical trials.

Pretreatment prognostic factors and treatment outcome in elderly patients with de novo acute myeloid leukemia.

BACKGROUND: Elderly patients with acute myeloid leukemia (AML) generally have an unfavorable clinical course and are under-represented in clinical trials. The aim of this study was to analyze the prognosis and treatment outcome of elderly AML patients. PATIENTS AND METHODS: We studied 205 AML patients aged 65 years or older at our hospital. Prior to study initiation, we designated 13 variables to be analyzed for their impact on complete remission (CR) rate and overall survival (OS). RESULTS: Induction regimen (standard chemotherapy) and good performance status (PS) (Eastern Cooperative Oncology Group PS 0-1) independently influenced the achievement of CR. Multivariate analysis also determined five poor prognostic factors for OS: poor PS (score 2-4), presence of comorbidities, elevated serum lactate dehydrogenase level (> or =2x upper normal limit), extreme leukocytosis (> or =100 x 10(9)/l) and marked thrombocytopenia (< or =20 x 10(9)/l). Age was not an independent contributing factor in terms of either CR attainment or OS duration. Low-risk patients, who possessed one or less non-leukocytosis poor prognostic factor, had significantly longer disease-free survival and OS than their high-risk counterparts. CONCLUSIONS: Elderly AML patients should be risk-stratified at diagnosis. Anthracycline-based induction chemotherapy would be the best therapeutic option for such patients.

Algorithmic generation of freely jointed hard sphere chains and properties of their inertial tensors.

A statistical algorithm, capable of generating a large number of freely jointed hard sphere chains, is presented. This is the first of a series of algorithms being developed to model unfolded proteins by different modes of hard sphere chains. The aim of these studies is to systematically investigate the effects of different factors, such as atomic radii, bond angles, torsion angles, chain length, etc., on the conformation of unfolded proteins and other random polymers. As continuous models, various types of hard sphere chains enable one to isolate the aforementioned factors one at a time for investigation and thus are advantageous over discrete lattice models. In particular, the freely jointed hard sphere chain model allows one to evaluate the excluded volume effect. As a first step in this endeavor, the average determinant D(N, r) and the average trace T(N, r) of the inertial tensor A of the random chains were calculated at various sphere radii r and chain lengths N. It is found that both the average determinant D(N, r) and the average trace T(N, r) scale linearly with chain length N after logarithmic transformation. However, the critical exponent of D(N, r) increases with r faster than that of T(N, r) as a result of the non-commutativity between the det operator and the average operator < >. The significance of the algorithm and the results obtained on understanding random polypeptide chains are discussed.

The effect of a side chain-backbone swap on protein stability.

To assess the relative importance of backbone hydrogen bonding (H-bonding) vs. side chain hydrophobicity in protein structural formation, a method called side chain-backbone swap is proposed. Such a method swaps the side chain and backbone portions of certain amino acid residues, such as Asp, Glu, Asn, Gln, Lys, and Arg. Such a swap retains the sequence of a polypeptide and preserves the identity of the backbone linkage. On the other hand, the swap disrupts backbone H-bonding geometry because of the introduction of extra methylene groups into the peptide backbone. In this project, we chose the two-stranded alpha-helical coiled-coil to implement side chain-backbone swap. A pair of 36-residue peptides was designed. The two peptides have identical sequence with four residues in each heptad repeat occupied by glutamyl residues. Each glutamic acid was incorporated either as alpha-glutamyl residue (the peptide is denoted as alpha-Glu-36) or as gamma-glutamyl residue (the peptide is denoted as gamma-Glu-36). The inter-conversion between the two peptides constitutes a side chain-backbone swap. Residues constituting the hydrophobic core of the coiled-coil, however, are left unchanged. The peptide pair was characterized by circular dichroism spectroscopy, reversed-phase liquid chromatography (RPLC), and two-dimensional nuclear magnetic resonance (NMR). The results indicate that alpha-Glu-36 is a two-stranded alpha-helical coiled-coil while gamma-Glu-36 lacks stable structural elements. It is concluded that, at least for coiled-coils where hydrophobic interactions are predominantly long-range, local backbone H-bonding is a required for structural formation, consistent with a hierarchic folding mechanism. The methodological implication of side chain-backbone swap is also discussed.

Contribution of translational and rotational motions to molecular association in aqueous solution.

Much uncertainty and controversy exist regarding the estimation of the enthalpy, entropy, and free energy of overall translational and rotational motions of solute molecules in aqueous solutions, quantities that are crucial to the understanding of molecular association/recognition processes and structure-based drug design. A critique of the literature on this topic is given that leads to a classification of the various views. The major stumbling block to experimentally determining the translational/rotational enthalpy and entropy is the elimination of vibrational perturbations from the measured effects. A solution to this problem, based on a combination of energy equi-partition and enthalpy-entropy compensation, is proposed and subjected to verification. This method is then applied to analyze experimental data on the dissociation/unfolding of dimeric proteins. For one translational/rotational unit at 1 M standard state in aqueous solution, the results for enthalpy (H degrees (tr)), entropy (S degrees (tr)), and free energy (G degrees (tr)) are H (degrees) (tr) = 4.5 +/- 1.5RT, S (degrees) (tr) = 5 +/- 4R, and G (degrees) (tr) = 0 +/- 5RT. Therefore, the overall translational and rotational motions make negligible contribution to binding affinity (free energy) in aqueous solutions at 1 M standard state.