A macroscopic anatomical study of the appropriate palpation zone of the gluteus medius muscle.

[Purpose] Few previous studies have delimitated the palpation zone of the gluteus medius muscle with a focus on its fiber bundles. The purpose of this study was to clarify the morphological characteristics of the gluteus medius muscle using an anatomical approach, and to define its proper palpation zone. [Participants and Methods] In this study, we evaluated thirteen halves of the pelvic region in seven formalin-fixed cadavers. We identified the borders between the iliotibial band and gluteus medius muscle, and between the gluteus medius and gluteus maximus muscles, on the iliac crest. Furthermore, we quantified the border points of the gluteus medius' fiber bundles and observed its anatomical and morphological characteristics. [Results] We identified two fiber bundles in the gluteus medius muscle, an anterior and a posterior fiber bundle, and detected that a portion of the posterior fibers was located subcutaneously. [Conclusion] We propose that the region where the posterior fibers of the gluteus medius muscle are located subcutaneously is an appropriate zone for the palpation of this muscle.

Prediction of Human Pharmacokinetic Profiles of the Antituberculosis Drug Delamanid from Nonclinical Data: Potential Therapeutic Value against Extrapulmonary Tuberculosis.

Delamanid has been studied extensively and approved for the treatment of pulmonary multidrug-resistant tuberculosis; however, its potential in the treatment of extrapulmonary tuberculosis remains unknown. We previously reported that, in rats, delamanid was broadly distributed to various tissues in addition to the lungs. In this study, we simulated human plasma concentration-time courses (pharmacokinetic profile) of delamanid, which has a unique property of metabolism by albumin, using two different approaches (steady-state concentration of plasma-mean residence time [Css-MRT] and physiologically based pharmacokinetic [PBPK] modeling). In Css-MRT, allometric scaling predicted the distribution volume at steady state based on data from mice, rats, and dogs. Total clearance was predicted by in vitro-in vivo extrapolation using a scaled albumin amount. A simulated human pharmacokinetic profile using a combination of human-predicted Css and MRT was almost identical to the observed profile after single oral administration, which suggests that the pharmacokinetic profile of delamanid could be predicted by allometric scaling from these animals and metabolic capacity in vitro. The PBPK model was constructed on the assumption that delamanid was metabolized by albumin in circulating plasma and tissues, to which the simulated pharmacokinetic profile was consistent. Moreover, the PBPK modeling approach demonstrated that the simulated concentrations of delamanid at steady state in the lung, brain, liver, and heart were higher than the in vivo effective concentration for Mycobacterium tuberculosis. These results indicate that delamanid may achieve similar concentrations in various organs to that of the lung and may have the potential to treat extrapulmonary tuberculosis.

Feature importance of machine learning prediction models shows structurally active part and important physicochemical features in drug design.

The objective of this study was to obtain the indicators of physicochemical parameters and structurally active sites to design new chemical entities with desirable pharmacokinetic profiles by investigating the process by which machine learning prediction models arrive at their decisions, which are called explainable artificial intelligence. First, we developed the prediction models for metabolic stability, CYP inhibition, and P-gp and BCRP substrate recognition using 265 physicochemical parameters for designing the molecular structures. Four important parameters, including the well-known indicator h_logD, are common in some in vitro studies; as such, these can be used to optimize compounds simultaneously to address multiple pharmacokinetic concerns. Next, we developed machine learning models that had been programmed to show structurally active sites. Many types of machine learning models were developed using the results of in vitro metabolic stability study of around 30000 in-house compounds. The metabolic sites of in-house compounds predicted using some prediction models matched experimentally identified metabolically active sites, with a ratio of number of metabolic sites (predicted/actual) of over 90%. These models can be applied to several screening projects. These two approaches can be employed for obtaining lead compounds with desirable pharmacokinetic profiles efficiently.

Predicting drug metabolism and pharmacokinetics features of in-house compounds by a hybrid machine-learning model.

We constructed machine learning-based pharmacokinetic prediction models with very high performance. The models were trained on 26138 and 16613 compounds involved in metabolic stability and cytochrome P450 inhibition, respectively. Because the compound features largely differed between the publicly available and in-house compounds, the models learned on the public data could not predict the in-house compounds, suggesting that outside of a certain applicability domain (AD), the prediction results are unreliable and can mislead the design of novel compounds. To exclude the uncertain prediction results, we constructed another machine learning model that determines whether the newly designed compound is inside or outside the AD. The AD was evaluated multi-dimensionally with some explanatory variables: The structural similarities and the probability obtained from the pharmacokinetic prediction model. The accuracy of predicting metabolic stability was 79.9% on the test set, increasing significantly to 93.6% after excluding the low-reliability compounds. The model properly classified the reliability of the compounds. After learning on the in-house compounds, the reliability model classified almost all (90%) of the public compounds as low reliability, indicating that the AD was properly determined by the model.

Absorption, distribution and excretion of the anti-tuberculosis drug delamanid in rats: Extensive tissue distribution suggests potential therapeutic value for extrapulmonary tuberculosis.

Delamanid (OPC-67683, Deltyba™, nitro-dihydro-imidazooxazoles derivative) is approved for the treatment of adult pulmonary multidrug-resistant tuberculosis. The absorption, distribution and excretion of delamanid-derived radioactivity were investigated after a single oral administration of 14 C-delamanid at 3 mg/kg to rats. In both male and female rats, radioactivity in blood and all tissues reached peak levels by 8 or 24 h post-dose, and thereafter decreased slowly. Radioactivity levels were 3- to 5-fold higher in lung tissue at time to maximum concentration compared with plasma. In addition, radioactivity was broadly distributed in various tissues, including the central nervous system, eyeball, placenta and fetus, indicating that 14 C-delamanid permeated the brain, retinal and placental blood barriers. By 168 h post-dose, radioactivity in almost all the tissues was higher than that in the plasma. Radioactivity was also transferred into the milk of lactating rats. Approximately 6% and 92% of radioactivity was excreted in the urine and feces, respectively, indicating that the absorbed radioactivity was primarily excreted via the biliary route. No significant differences in the absorption, distribution and excretion of 14 C-delamanid were observed between male and female rats. The pharmacokinetic results suggested that delamanid was broadly distributed to the lungs and various tissues for a prolonged duration of time at concentrations expected to effectively target tuberculosis bacteria. These data indicate that delamanid, in addition to its previously demonstrated efficacy in pulmonary tuberculosis, might be an effective therapeutic approach to treating extrapulmonary tuberculosis. Copyright © 2017 John Wiley & Sons, Ltd.

Antitubercular Agent Delamanid and Metabolites as Substrates and Inhibitors of ABC and Solute Carrier Transporters.

Delamanid (Deltyba, OPC-67683) is the first approved drug in a novel class of nitro-dihydro-imidazooxazoles developed for the treatment of multidrug-resistant tuberculosis. Patients with tuberculosis require treatment with multiple drugs, several of which have known drug-drug interactions. Transporters regulate drug absorption, distribution, and excretion; therefore, the inhibition of transport by one agent may alter the pharmacokinetics of another, leading to unexpected adverse events. Therefore, it is important to understand how delamanid affects transport activity. In the present study, the potencies of delamanid and its main metabolites as the substrates and inhibitors of various transporters were evaluated in vitro Delamanid was not transported by the efflux ATP-binding cassette (ABC) transporters P-glycoprotein (P-gp; MDR1/ABCB1) and breast cancer resistance protein (BCRP/ABCG2), solute carrier (SLC) transporters, organic anion-transporting polypeptides, or organic cation transporter 1. Similarly, metabolite 1 (M1) was not a substrate for any of these transporters except P-gp. Delamanid showed no inhibitory effect on ABC transporters MDR1, BCRP, and bile salt export pump (BSEP; ABCB11), SLC transporters, or organic anion transporters. M1 and M2 inhibited P-gp- and BCRP-mediated transport but did so only at the 50% inhibitory concentrations (M1, 4.65 and 5.71 µmol/liter, respectively; M2, 7.80 and 6.02 µmol/liter, respectively), well above the corresponding maximum concentration in plasma values observed following the administration of multiple doses in clinical trials. M3 and M4 did not affect the activities of any of the transporters tested. These in vitro data suggest that delamanid is unlikely to have clinically relevant interactions with drugs for which absorption and disposition are mediated by this group of transporters.

Anatomical structure of the subcutaneous tissue on the anterior surface of human thigh.

The anterior thighs of 16 limbs from eight donated cadavers were observed using ultrasonic imaging and gross dissection with a specific focus on the subcutaneous tissue, which is considered an auxiliary element of locomotion. On ultrasonic imaging, the subcutaneous tissue was found to comprise multiple layers. The number of layers gradually decreased on progressing distally in the thigh. On gross dissection, a lot of fatty tissue and loose multiple laminar structures were observed in the medial and proximal areas. However, on progressing distally, these layers thinned out and became less fatty. Cutaneous nerves were apparent among the layers below the dermis. In addition, there were many associated fiber bundles between the dermis and muscle fascia, some of which appeared to be so-called skin ligaments that run through the subcutaneous tissue perpendicularly from the fascia to dermis, accompanying cutaneous nerve fibers and blood vessels. While identifying the peripheral cutaneous nerve fibers, several anastomosing rami and neural networks were recognized. These observations suggest that skin ligaments could be elements regulating motor restriction during muscular movement.

Pharmacokinetics and Metabolism of Delamanid, a Novel Anti-Tuberculosis Drug, in Animals and Humans: Importance of Albumin Metabolism In Vivo.

Delamanid, a new anti-tuberculosis drug, is metabolized to M1, a unique metabolite formed by cleavage of the 6-nitro-2,3-dihydroimidazo[2,1-b] oxazole moiety, in plasma albumin in vitro. The metabolic activities in dogs and humans are higher than those in rodents. In this study, we characterized the pharmacokinetics and metabolism of delamanid in animals and humans. Eight metabolites (M1-M8) produced by cleavage of the imidazooxazole moiety of delamanid were identified in the plasma after repeated oral administration by liquid chromatography-mass spectrometry analysis. Delamanid was initially catalyzed to M1 and subsequently metabolized by three separate pathways, which suggested that M1 is a crucial starting point. The major pathway in humans was hydroxylation of the oxazole moiety of M1 to form M2 and then successive oxidation to the ketone form (M3) mainly by CYP3A4. M1 had the highest exposure among the eight metabolites after repeated oral dosing in humans, which indicated that M1 was the major metabolite. The overall metabolism of delamanid was qualitatively similar across nonclinical species and humans but was quantitatively different among the species. After repeated administration, the metabolites had much higher concentrations in dogs and humans than in rodents. The in vitro metabolic activity of albumin on delamanid probably caused the species differences observed. We determined that albumin metabolism is a key component of the pharmacokinetics and metabolism of delamanid. Nonhepatic formation of M1 and multiple separate pathways for metabolism of M1 suggest that clinically significant drug-drug interactions with delamanid and M1 are limited.

Metabolic Mechanism of Delamanid, a New Anti-Tuberculosis Drug, in Human Plasma.

The metabolism of delamanid (OPC-67683, Deltyba), a novel treatment of multidrug-resistant tuberculosis, was investigated in vitro using plasma and purified protein preparations from humans and animals. Delamanid was rapidly degraded by incubation in the plasma of all species tested at 37°C, with half-life values (hours) of 0.64 (human), 0.84 (dog), 0.87 (rabbit), 1.90 (mouse), and 3.54 (rat). A major metabolite, (R)-2-amino-4,5-dihydrooxazole derivative (M1), was formed in the plasma by cleavage of the 6-nitro-2,3-dihydroimidazo(2,1-b)oxazole moiety of delamanid. The rate of M1 formation increased with temperature (0-37°C) and pH (6.0-8.0). Delamanid was not converted to M1 in plasma filtrate, with a molecular mass cutoff of 30 kDa, suggesting that bioconversion is mediated by plasma proteins of higher molecular weight. When delamanid was incubated in plasma protein fractions separated by gel filtration chromatography, M1 was observed in the fraction consisting of albumin, γ-globulin, and α1-acid glycoprotein. In pure preparations of these proteins, only human serum albumin (HSA) metabolized delamanid to M1. The formation of M1 followed Michaelis-Menten kinetics in both human plasma and the HSA solution, with similar Km values: 67.8 µM in plasma and 51.5 µM in HSA. The maximum velocity and intrinsic clearance values for M1 were also comparable in plasma and HSA. These results strongly suggest that albumin is predominantly responsible for metabolizing delamanid to M1. We propose that delamanid degradation by albumin begins with a nucleophilic attack of amino acid residues on the electron-poor carbon at the 5 position of nitro-dihydro-imidazooxazole, followed by cleavage of the imidazooxazole moiety to form M1.

Expression levels of multidrug resistance-associated protein 4 (MRP4) in human leukemia and lymphoma cell lines, and the inhibitory effects of the MRP-specific inhibitor MK-571 on methotrexate distribution in rats.

In the development of anti-blood cancer drugs, the chronic myelocytic leukemia (KU812), acute myelocytic leukemia (KG-1) and lymphoma (U937) cell lines are commonly used in preclinical pharmacology studies as human cancer xenograft models in mice. In the present study, mRNA expression levels of typical human ATP-binding cassette (ABC) transporters in these human blood cancer cell lines were analyzed by real-time polymerase chain reaction (RT-PCR). Based on the results, the expression level of multidrug resistance-associated protein 4 (MRP4) was found to be extremely high in KU812 cells compared with those of other transporters. Additionally, MRP4 expression levels were found to be relatively high in U937, KG-1 and a blood cell line derived from a healthy subject (RPMI 1788). In addition, to elucidate the contribution of MRP4 to the methotrexate (MTX) distribution in normal blood cells and tissues, [(3)H]MTX was intravenously (i.v.) administered to two groups of rats. Animals in one group received [(3)H]MTX only; the other group was concomitantly administered i.v. MK-571, a typical inhibitor of MRP transporters. No marked difference was observed between the two groups; the Kp values (tissue concentration/plasma concentration) of the concomitant group showed slightly higher values compared with those of the MTX alone group in erythrocytes (1.4 times, P<0.001), spleen (1.3 times, P<0.05) and thymus (1.2 times, P<0.05), respectively. Although in the present study we could not evaluate the direct involvement of MRP4 in blood cancer cells in which MRP4 expression was excessively high, these results suggest a possible functional role of MRP4 in blood cancer cells and albeit only slightly in normal blood cells/tissues.

Nuclei of the human raphe.

Along the raphe of the brain stem, a series of small neuronal groups can be observed in the medulla oblongata, the pons and the mesencephalon. The neurons located in and adjacent to the raphe are considered to produce mainly serotonin (5-HT). The groups of nuclei containing 5-HT were first reported in experimental animals in the early 1960s. The presence of such nuclei, however, has not yet been brought to light in the human brainstem except the few atlases, although in several neuroanatomy textbooks, extrapolated data are shown in the form of drawings as if they were the data from the human brain. The aim of this study is to present microscopic photos of such raphe nuclei made from serial sections of the human brainstem, and to clarify the differences between findings in human and textbook drawings from animal data.

Evaluation of the spinal cord white matter.

Morphological findings or evaluations of the nervous system have traditionally concentrated on cell somata; evaluations of the white matter have not been put forward up to now. This study was conducted to evaluate the white matter in the spinal cord with the LPH discriminative staining method which was proposed by Goto. Thanks to the minimum shrinkage ratio (10 ± 0% in length) which this technique allows, it is possible to evaluate the sizes of nerve axons, and to compare the arrangement of nerve fibers in various parts of the spinal white matter. As the axonal sizes reflect nerve conduction velocities, we would like to emphasize that these sizes or the differences in the arrangement of axons may be important for a better understanding of neurosymptomatology.

Morphological observation of the horseshoe kidney with circumaortic venous ring.

In a student course of gross anatomy dissection at Knagawa Dental College in 2010, we found an extremely rare case of the horseshoe kidney with circumaortic venous ring in a 43-year-old Japanese male cadaver. In this case, the kidney consisted of three parts: the original kidneys on both sides and an isthmus between them. The location of each kidney was lower than that of the normal kidney. The hili on both sides opened toward the ventral direction, and the ureters descended in front of the isthmus and entered the bladder normally. This horseshoe kidney had original left and right renal arteries that branched from the abdominal aorta. There were also two surplus arteries. There were three renal veins on the left side, and these renal veins formed the circumaortic venous ring. The anatomical and embryological significance of this anomaly and its associated vascular system are discussed. The anatomy and etiology of these anomalous structures are discussed with references in the literature.

Decrease in brain distribution of fluvoxamine in experimental hyperlipidemic rats.

PURPOSE: Many clinical reports and trials have suggested that fluvoxamine (FLV) reduces plasma lipoprotein levels. However, few studies have reported the effect of plasma lipoproteins on FLV pharmacokinetics. The aim of the present study was to investigate the affinities of FLV to plasma lipoproteins and the effect of plasma lipoproteins on the biodistribution of FLV using an experimental hyperlipidemic (HL) rat model. METHODS: HL rats were prepared by intraperitoneal administration of Poloxamer-407 solution (1.0 g/kg). In vitro protein binding and distribution of FLV in plasma lipoproteins were determined in control and HL rats. In vivo pharmacokinetic study (intravenous administration of FLV, 5.0 mg/kg) and biodistribution analysis for brain and liver at a steady state (infusion, 1.5 mg/kg/hr, 6 hrs) were also performed. RESULTS: The plasma protein binding of FLV was around 83% and 95% in control and HL rats, respectively, whereas the FLV recoveries in triglyceride-rich lipoprotein fractions were increased in HL. Therefore, the elevation of lipoproteins was likely responsible for the increase in protein binding in HL. After intravenous administration, the area under the plasma concentration vs. time curve (AUC) in HL was 3.9-fold greater than that in control rats, whereas the distribution ratio of FLV plasma concentration to the brain at a steady state was decreased to approximately 20% of that of the control. CONCLUSIONS: FLV has an affinity to plasma lipoproteins, and their elevation might decrease the FLV biodistribution to brain; the plasma lipoprotein levels could not be found to correlate positively with the FLV pharmacokinetic effect in brain, but rather may attenuate it.

Double superior vena cava and anomaly of cardiovascular system with a review of the literature.

In a student course of gross anatomy dissection at Kanagawa Dental College in 2008, we found an extremely rare case of the double superior vena cava that has a shunt between the right and left atria of a 81-year-old Japanese male cadaver. The left superior vena cava passed through the space between the left cardiac auricle and the left pulmonary vein and entered the coronary sulcus. Then it opened near the opening of the inferior vena cava as the coronary venous sinus to the right atrium. The upper edge of the interatrial septum was located at the site where the right superior vena cava opened to the right atrium. Accordingly, the right atrium connected with left atrium through this site. We discuss the anatomy and etiology of these anomalous structures with a brief review of the literature.

Pharmacokinetics of clomipramine, an antidepressant, in poloxamer 407-induced hyperlipidaemic model rats.

OBJECTIVE: This study was undertaken to investigate the effects of hyperlipidaemia on the pharmacokinetics of clomipramine, an antidepressant, particularly addressing the change of clomipramine distribution to plasma components in poloxamer 407-induced hyperlipidaemia model rats. METHODS: Clomipramine pharmacokinetic studies in hyperlipidaemic rats were performed with clomipramine continuous infusion. Furthermore, clomipramine protein binding and distribution to the brain and plasma components such as lipoproteins were investigated. KEY FINDINGS: Mean plasma concentration of clomipramine at steady state during continuous infusion (17.5µg/min/kg) in hyperlipidaemic rats (0.45±0.01µg/ml) was significantly higher than that in the control rats (0.30±0.02µg/ml). However, the amount of clomipramine in the brain in hyperlipidaemic rats (0.31±0.06µg/g) was dramatically lower than in the control rats (1.89±0.13µg/g). However, the plasma unbound fraction in hyperlipidaemic rats (0.98±0.05%) was significantly lower than that of the control rats (6.51±0.62%). CONCLUSIONS: Lower distribution to the brain and lower plasma clearance of clomipramine in hyperlipidaemic rats resulted from lower plasma unbound fraction because of higher lipid-rich protein contents in blood. Results of this study provide useful information for dosage adjustment of clomipramine in hyperlipidaemia.

Creation of cross-linked electrospun isotypic-elastin fibers controlled cell-differentiation with new cross-linker.

Effective application of elastin materials for vascular grafts in tissue engineering requires these materials to retain the elastic and biological properties of native elastin. To clarify the influence of soluble elastin isotypes on vascular smooth muscle cells (VSMCs), soluble elastin was prepared from insoluble elastin by hydrolysis with oxalic acid. Its fractions were separated and classified into three isotypes. Elastin retaining 2.25 mol% of cross-linked structures exhibited significant differentiation of VSMCs, which adhered to the elastin with contraction phenotypes similar to that of native elastin, causing proliferation to cease. This trend was more strongly demonstrated in cotton-like elastin fibers with a new cross-linker. The results suggest that elastin isotypes could be applied as new effective biomaterials for suppressing intimal hyperplasia in vascular grafts.

Morphometric and functional correlation of human neuronal somata: pyramidal motor, special sensory and general sensory systems.

Using an ideal tissue preparation method, we found a definite correlation between various human neuronal somata from the view point of accurate morphometry and functional evaluations. We believe this study may be of value, or even indispensable in the correct understanding of neurological symptomatology and phenomenology.

Effect of serum lipids on the pharmacokinetics of atazanavir in hyperlipidemic rats.

Atazanavir (ATV) has been successfully used in HIV patients with severe hyperlipidemia (HL); however, little is known about the pharmacokinetics of ATV in HL. The aim of this study was to investigate the pharmacokinetics of ATV in HL. With the increase of serum lipids, the protein binding rate in HL rats (approximately 97%) was significantly higher than that in control (approximately 87%). After intravenous (iv), oral (po) and intraportal (ip) administration of ATV at a dosage of 7 mg/kg, AUCs in HL rats were 12.41, 5.24 and 8.89 microg/mLh, respectively, and were significantly higher than those in control rats (4.09, 1.70 and 3.38 microg/mLh). Despite the decrease of distribution volume (Vd(ss)), the terminal half-life (t(1/2)) in HL tended to be shorter than in control, and hepatic distribution of ATV in HL rats was 4.8-fold increases. These results suggested that the uptake of ATV into liver might counteract the decrease of Vd(ss). On the other hand, there was no significant difference in bioavailability, and the lymphatic transport to AUC showed no statistical change. In conclusion, although the protein binding rate and AUC were significantly increased, the pharmacokinetics of ATV might be tolerated in HL.