Anti-fatigue effect of an enzymatically derived deer velvet extract through muscle damage recovery and improvement of antioxidant levels.

ETHNOPHARMACOLOGICAL RELEVANCE: Deer velvet (DV) has been extensively used in traditional Oriental medicine to treat various diseases. Its pharmacological spectrum encompasses tonicity, longitudinal bone growth of adolescence, blood retention, hemopoiesis facilitation, enhancement of organ function, physical function improvement, and augmentation of physical vitality. Among its myriad effects, DV notably exhibits anti-fatigue properties; however, its specific mode of action is yet to be fully elucidated. AIM OF THE STUDY: This study was undertaken to investigate the anti-fatigue and exercise performance-enhancing effects of YC-1101(HENKIV®), an enzymatically derived DV extract, in C2C12 cell lines and forced swimming mouse models. MATERIALS AND METHODS: The effect of YC-1101 on increasing cell growth and lowering lactate dehydrogenase (LDH) activity was assessed in C2C12. The antioxidative effects of YC-1101 and its mechanistic underpinnings were also evaluated in C2C12 cells. Moreover, mice were subjected to an exhaustive swimming test subsequent to 3 weeks of YC-1101 extract administration. Fatigue-associated biochemical parameters, such as LDH activity and lactate, superoxide dismutase, glutathione peroxidase, and malondialdehyde levels, were measured in serum and muscle tissues. RESULTS: YC-1101 significantly promoted myoblast growth and reduced LDH activity, indicative of a cell-proliferative effect. Notably, free radical scavenging assays and analysis of reactive oxygen species production and antioxidant-related mRNA expression corroborated the significant involvement of YC-1101 in antioxidation, an important mechanism in anti-fatigue processes. Furthermore, animal experiments demonstrated prolonged swimming endurance and inhibition of muscle LDH accumulation in forced swimming mouse models. Serum biochemical analysis further revealed significant modulation of the expression of anti-fatigue-related biomarkers. Various bioactive low-molecular-weight DV peptides were enriched in YC-1101 compared to YHC-BE-2038 (a DV extract without enzymatic digestion). The anti-fatigue effect of YC-1101 was significantly stronger than that of YHC-BE-2038. CONCLUSIONS: These findings suggest the potential of YC-1101 as a nutraceutical adjunct in ameliorating fatigue, concurrently facilitating muscle damage recovery, and exerting antioxidant effects via the nuclear factor E2-related factor 2-Kelch-like ECH-associated protein-1 pathway. It can be assumed that the complex action of low-molecular-weight DV peptides produced during the enzymatic degradation process was effective, and the further research is needed.

Uncaria Rhynchophylla and hirsuteine as TRPV1 agonists inducing channel desensitization.

ETHNOPHARMACOLOGICAL RELEVANCE: Uncaria rhynchophylla (UR) is recognized for its therapeutic applications in treating hypertension and inflammation. However, the specific molecular mechanisms how UR and its bioactive constituents modulate inflammatory pathways remain unknown. This study investigates the effects of UR extract and its constituent, hirsuteine (HST), on TRPV1 channel modulation which is related to hypertension and inflammation. MATERIALS AND METHODS: Electrophysiological recordings and calcium imaging experiments were conducted to assess TRPV1 activation by UR extract and HST in HEK293T cells and sensory neurons. RESULTS: UR extract and HST activated TRPV1 in HEK293T cells, with repeated applications causing channel desensitization. HST application on TRPV1-positive sensory neurons significantly reduced electrical activity compared to capsaicin. CONCLUSION: This study demonstrated UR extract and HST are a novel TRPV1 agonists inducing channel desensitization and a potent agent for treatment of TRPV1 dependent pain relief.

Treatment of Kienböck's Disease Using Fourth and Fifth Extensor Compartmental Artery Vascularized Bone Grafts.

BACKGROUND: This study evaluated the radiological and clinical outcomes of bone grafts using fourth and fifth extensor compartmental arteries (4+5 ECAs) for the treatment of Kienböck's disease. MATERIALS AND METHODS: In total, 21 patients (12 men and 9 women; mean age, 41 years; range, 19-59 years) were followed for a mean of 33 months. Radiological images were analyzed for the Lichtman stage, carpal height ratio, radioscaphoid angle, and Stahl's index. Clinical evaluation included range of motion, visual analog scale (VAS) score, grip strength, modified Mayo wrist score (MMWS), Lichtman outcome score, and Disabilities of the Arm, Shoulder and Hand (DASH) score. At the time of surgery, 6, 14, and 1 patients had Lichtman stages II, IIIA, and IIIB, respectively. RESULTS: At the final follow-up visit, grip strength had improved from 65.4% to 79.7%, wrist extension had improved from 43° to 57°, and flexion had improved from 42° to 50°. There were no significant changes in the carpal height ratio, Stahl's index, or radioscaphoid angle. The mean VAS score was 1.7, and the mean DASH score was 6.9. The mean MMWS was 87.9, with excellent and good outcomes in 6 and 11 patients, respectively. Satisfactory Lichtman outcome scores were observed in 81%. Body mass index had a strong correlation and age had a weak correlation with MMWS (coefficient=-0.534, P=.013, and coefficient=-0.393, P=.078, respectively). CONCLUSION: The 4+5 ECA bone graft is effective for the treatment of Kienböck's disease in young patients with low body mass index. [Orthopedics. 202x;4x(x)xx-xx.].

The Root Extract of Rosa multiflora Ameliorates Nonalcoholic Steatohepatitis Development via Blockade of De Novo Lipogenesis and Inflammation.

Nonalcoholic steatohepatitis (NASH) is characterized by severe inflammation and fibrosis due to an excessive accumulation of triglycerides (TGs) in the liver with a dysregulated de novo lipogenesis (DNL) pathway. In this study, we aimed to evaluate the effectiveness of YC-1102, an extract obtained from the roots of Rosa multiflora, as a nutritional supplement in a diet-induced NASH mouse model. C57BL/6 wild-type mice were fed a fructose, palmitate, and cholesterol (FPC)-containing diet for 16 weeks to induce experimental NASH. A daily oral gavage of YC-1102 and obetichoic acid (OCA) was conducted for 9 weeks. After sacrifice, disease parameters related to hepatic lipids, inflammation, and fibrosis were evaluated. The treatment with YC-1102 significantly decreased the liver/body weight ratio, epididymal fat weight, and plasma ALT and AST levels, which are indicators of NASH injuries. YC-1102 attenuated hepatic lipid accumulation by inhibiting the transcription of DNL genes in the livers exhibiting NASH. Additionally, we found that YC-1102 blocked the development of hepatic inflammation and fibrosis by directly disturbing macrophage activation, resulting in an amelioration of hepatic fibrosis. Our findings suggest that YC-1102 could ameliorate NASH progression by inhibiting uncontrolled DNL and inflammation.

Cannabidiol Alleviates Chronic Prostatitis and Chronic Pelvic Pain Syndrome via CB2 Receptor Activation and TRPV1 Desensitization.

PURPOSE: This study elucidates the mechanism of the physiological effect of cannabidiol (CBD) by assessing its impact on lipopolysaccharide (LPS)-induced inflammation in RWPE-1 cells and prostatitis-induced by 17ß-estradiol and dihydrotestosterone in a rat model, focusing on its therapeutic potential for chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS). MATERIALS AND METHODS: RWPE-1 cells were stratified in vitro into three groups: (1) controls, (2) cells with LPS-induced inflammation, and (3) cells with LPS-induced inflammation and treated with CBD. Enzyme-linked immunosorbent assays and western blots were performed on cellular components and supernatants after administration of CBD. Five groups of six Sprague-Dawley male rats were assigned: (1) control, (2) CP/CPPS, (3) CP/CPPS and treated with 50 mg/kg CBD, (4) CP/CPPS and treated with 100 mg/kg CBD, and (5) CP/CPPS and treated with 150 mg/kg CBD. Prostatitis was induced through administration of 17ß-estradiol and dihydrotestosterone. After four weeks of CBD treatment, a pain index was evaluated, and prostate tissue was collected for subsequent histologic examination and western blot analysis. RESULTS: CBD demonstrated efficacy in vivo for CP/CPPS and in vitro for inflammation. It inhibited the toll-like receptor 4 (TLR4)/nuclear factor-kappa B (NF-κB) pathway by activating the CB2 receptor, reducing expression of interleukin-6, tumor necrosis factor-alpha, and cyclooxygenase-2 (COX2) (p<0.01). CBD exhibited analgesic effects by activating and desensitizing the TRPV1 receptor. CONCLUSIONS: CBD inhibits the TLR4/NF-κB pathway by activating the CB2 receptor, desensitizes the TRPV1 receptor, and decreases the release of COX2. This results in relief of inflammation and pain in patients with CP/CPPS, indicating CBD as a potential treatment for CP/CPPS.

Effect of YC-1102 on the Improvement of Obesity in High-Fat Diet-Induced Obese Mice.

Obesity is one of the major risk factors for metabolic diseases worldwide. This study examined the effects of YC-1102, an extract derived from the roots of Rosa multiflora, on 3T3-L1 preadipocytes and high-fat diet (HFD)-induced obese mice. In vivo experiments involved the oral administration of YC-1102 (100, 150, and 200 mg/kg body weight) daily to mice for eight weeks. YC-1102 was found to downregulate the expressions of PPARγ and C/EBPα during adipogenesis, inhibiting adipocyte differentiation and upregulating the expression of PGC-1α for energy metabolism to enhance mitochondrial biogenesis and fatty acid oxidation. It has been shown that daily administration of YC-1102 to mice receiving a HFD prevented an increase in body weight and the accumulation of body fat. YC-1102 administration also reduced TG, TC, and LDL cholesterol levels, as well as glucose and leptin levels, and increased adiponectin levels, thus effectively inhibiting the metabolism of lipids. YC-1102-treated mice showed significant reductions in the mRNA expression of PPARγ and C/EBPα. The levels of PGC-1α involved in energy metabolism increased significantly in the YC-1102-treated mice when compared to the HFD-treated mice. According to the findings of this study, YC-1102 has a dual mechanism that reduces transcription factors that promote the differentiation of adipocytes and increases transcription factors that promote energy consumption.

Correction to: Enzyme­derived deer velvet extract activate the immune response in cyclophosphamide­induced immunosuppressive mice.

[This corrects the article DOI: 10.1007/s10068-023-01275-4.].

Endoscopic Versus Open In Situ Decompression for the Management of Cubital Tunnel Syndrome.

This study compared the results of endoscopic cubital tunnel release (eCuTR) with those of open cubital tunnel release (oCuTR) for the management of cubital tunnel syndrome (CuTS). In this retrospective study, 35 patients underwent eCuTR or oCuTR. Group I and group II consisted of 16 patients undergoing eCuTR and 19 patients undergoing oCuTR, respectively. Patients were asked to report paresthesia and pain, and electromyography was performed. The Dellon and Bishop classifications were used. The Disabilities of the Arm, Shoulder and Hand (DASH) and visual analog scale (VAS) pain scores were recorded, as well as the key pinch strength and two-point discrimination. The incision length and operation duration were noted. The mean follow-up was 39 months. The mean operating time was longer in the endoscopy group (43 vs 22 minutes). Overall, 34.3% (n=12) of the cases were classified as Dellon grade II and 65.7% (n=23) were classified as Dellon grade III. According to the Bishop score, excellent or good results were obtained for 75% of the patients in the eCuTR group and 78.9% of the patients in the oCuTR group. In the eCuTR and oCuTR groups, all outcome measures improved after surgery: DASH score (preoperative, 37.7 vs 30.7; postoperative, 15.4 vs 20), VAS score (preoperative, 7.8 vs 7.3; postoperative, 4.3 vs 4.1), pinch strength (preoperative, 74 vs 66; postoperative, 93 vs 84), and two-point discrimination (preoperative, 5.6 vs 6.6; postoperative, 4.9 vs 4.5). No significant difference was apparent between the two techniques in outcomes. However, the endoscopic release had a higher reoperation rate and took twice as long to perform despite having a shorter incision. [Orthopedics. 202x;4x(x):xx-xx.].

Enzyme-derived deer velvet extract activate the immune response in cyclophosphamide-induced immunosuppressive mice.

Deer velvet (DV) is an oriental traditional medicine used to treat various diseases. The present study examined the effect of flavourzyme-derived DV extract (YC-1101) on macrophages and an immunosuppressed mouse model. YC-1101 induced activation of macrophages as measured by nitric oxide production, cell proliferation, and cytokine release via concentration-dependent phosphorylation of c-Jun N-terminal kinase, extracellular signal-regulated kinase, and AKT, and nuclear translocation of p65 in macrophages. In addition, oral YC-1101 administration significantly increased splenocyte proliferation and natural killer cell activity in the immunosuppressed mouse model. Moreover, the levels of immune-related cytokines such as tumor necrotic factor-α, interferon-γ, and interleukin-2 were significantly increased by YC-1101 treatment comparable to the control group. Thus, these results suggest that YC-1101 is an efficient natural ingredient that has an immune-enhancing effect, and it might be a potential functional food for improving immunity.

Correlations of Sesamoid Bone Subluxation with the Radiologic Measures of Hallux Valgus and Its Clinical Implications.

Background and Objectives: Hallux valgus is one of the most common chronic foot complaints, with prevalences of over 23% in adults and up to 35.7% in older adults. However, the prevalence is only 3.5% in adolescents. The pathological causes and pathophysiology of hallux valgus are well-known in various studies and reports. A change in the position of the sesamoid bone under the metatarsal bone of the first toe is known to be the cause of the initial pathophysiology. Purpose: The relationships between the changes in the location of the sesamoid bone and each radiologically measured angle and joint congruency in the hallux valgus remain as yet unknown. Therefore, this study investigated the relationships of sesamoid bone subluxation with the hallux valgus angle, intermetatarsal angle, and metatarsophalangeal joint congruency in hallux valgus patients. The goal is to know the hallux valgus angle, the intermetatarsal angle, and metatarsophalangeal joint congruency's correlation with hallux valgus severity and prognosis by revealing the relationship between each measured value and sesamoid bone subluxation. Materials and Methods: We reviewed 205 hallux valgus patients who underwent radiographic evaluation and subsequent hallux valgus correction surgery in our orthopedic clinic between March 2015 and February 2020. Sesamoid subluxation was assessed using a new five-grade scale on foot radiographs, and other radiologic measurements were assessed, such as hallux valgus angle, the intermetatarsal angle, distal metatarsal articular angle, joint congruency, etc. Conclusions: Measurements of the hallux valgus angle, interphalangeal angle, and joint congruency exhibited high interobserver and intraobserver reliabilities in this study. They also showed correlations with sesamoid subluxation grade.

Taekwondo Athlete's Bilateral Achilles Tendon Rupture: A Case Report.

(1) Background: Achilles tendon rupture is a common sports injury that may result in severe disability. The overall incidence of Achilles tendon rupture is increasing as a result of growing sports participation. However, cases of spontaneous bilateral Achilles tendon rupture with no underlying disease or risk factors, such as systemic inflammatory disease, steroid or (fluoro)quinolone antibiotics use, are rare. (2) Objective: Here, we report a case of a Taekwondo athlete's bilateral Achilles tendon rupture after kicking and landing. By sharing the experience of treatment and the patient's course, we suggest one of the possible treatment options and the need to establish a treatment method. (3) Procedure: A 23-year-old male Taekwondo athlete visited the hospital, presenting foot plantar flexion failure and severe pain in both tarsal joints, which had occurred upon kicking and landing on both feet earlier that day. During surgery, no degenerative changes or denaturation were observed in the ruptured areas of the Achilles tendons. Bilateral surgery was performed using the modified Bunnel method on the right side and minimum-section suturing on the left side was performed using the Achillon system, followed by lower limb casting. (4) Result: Good outcomes were observed on both sides at 19 months postoperatively. (5) Conclusion: The possibility of bilateral Achilles tendon rupture during exercise in young subjects with no risk factors should be acknowledged, especially in association with landing. In addition, in athletes, even if there is a possibility of complications, surgical treatment should be considered for functional recovery.

Optimization of a histamine-induced allergic conjunctivitis model in Guinea pigs.

Allergic conjunctivitis is one of the most common immune diseases in the field of ophthalmology. The number of patients suffering from allergic conjunctivitis has been increasing, and there is still a strong need for development of therapeutic agents for this disease. In drug development, the utmost important point to improve the success probability is to accurately single out good compounds in the early stage of drug development. Therefore, drug efficacy evaluations in the nonclinical stage should be conducted with high reliability and accuracy. However, there are no literatures investigating the preparation and evaluation methods of animal models of conjunctivitis in details nor the standardized criteria. In this study, we verified the reproducibility of an animal model in the previous report and made improvements in test methods focusing on a guinea pig model of histamine-induced allergic conjunctivitis. Furthermore, the drug efficacy evaluation was conducted using a commercially available antihistamine drug, levocabastine hydrochloride, to judge the suitability of the improved model. As a result, the dose level of histamine needed to be increased to use the existing model for drug efficacy evaluation, but allergic-like symptoms were induced very easily and stably in this model. For observations of symptoms of conjunctivitis, we eliminated ambiguity of evaluation by adopting the Draize scale and ensured a higher objectivity on the evaluation method. The drug efficacy evaluation of levocabastine hydrochloride in the prepared model revealed that drug efficacy of the antihistamine drug was captured according to the standardized test method and highly-reproducible results were obtained.

Tentonin 3/TMEM150c Confers Distinct Mechanosensitive Currents in Dorsal-Root Ganglion Neurons with Proprioceptive Function.

Touch sensation or proprioception requires the transduction of mechanical stimuli into electrical signals by mechanoreceptors in the periphery. These mechanoreceptors are equipped with various transducer channels. Although Piezo1 and 2 are mechanically activated (MA) channels with rapid inactivation, MA molecules with other inactivation kinetics have not been identified. Here we report that heterologously expressed Tentonin3 (TTN3)/TMEM150C is activated by mechanical stimuli with distinctly slow inactivation kinetics. Genetic ablation of Ttn3/Tmem150c markedly reduced slowly adapting neurons in dorsal-root ganglion neurons. The MA TTN3 currents were inhibited by known blockers of mechanosensitive ion channels. Moreover, TTN3 was localized in muscle spindle afferents. Ttn3-deficient mice exhibited the loss of coordinated movements and abnormal gait. Thus, TTN3 appears to be a component of a mechanosensitive channel with a slow inactivation rate and contributes to motor coordination. Identification of this gene advances our understanding of the various types of mechanosensations, including proprioception.

Anoctamin 1 (TMEM16A) is essential for testosterone-induced prostate hyperplasia.

Benign prostatic hyperplasia (BPH) is characterized by an enlargement of the prostate, causing lower urinary tract symptoms in elderly men worldwide. However, the molecular mechanism underlying the pathogenesis of BPH is unclear. Anoctamin1 (ANO1) encodes a Ca(2+)-activated chloride channel (CaCC) that mediates various physiological functions. Here, we demonstrate that it is essential for testosterone-induced BPH. ANO1 was highly amplified in dihydrotestosterone (DHT)-treated prostate epithelial cells, whereas the selective knockdown of ANO1 inhibited DHT-induced cell proliferation. Three androgen-response elements were found in the ANO1 promoter region, which is relevant for the DHT-dependent induction of ANO1. Administration of the ANO1 blocker or Ano1 small interfering RNA, inhibited prostate enlargement and reduced histological abnormalities in vivo. We therefore concluded that ANO1 is essential for the development of prostate hyperplasia and is a potential target for the treatment of BPH.

Curcumin attenuates allergic airway inflammation and hyper-responsiveness in mice through NF-κB inhibition.

ETHNOPHARMACOLOGICAL RELEVANCE: Curcumin, a polyphenol compound from Curcuma longa L. has been used for centuries as an anti-inflammatory remedy including asthma. Curcumin has been reported to exert an anti-inflammatory effect, in part, through inhibition of the NF-κB pathway. AIM OF THE STUDY: The purposes of this study were to determine whether curcumin inhibits NF-κB-dependent transcription in vitro, and test whether treatment with curcumin reduces allergen-induced airway inflammation and hyper-responsiveness in a mouse model of asthma through inhibition of NF-κB pathway. MATERIALS AND METHODS: The effect of curcumin on NF-κB transcriptional activity was investigated using a cell-based luciferase reporter assay in A549 cells and by measuring inhibitory κBα (IκBα), p65, and p50 levels after exposure of Raw264.7 cells to lipopolysaccharide (LPS). BALB/c mice were sensitized to ovalbumin (OVA) by intraperitoneal injection, and challenged with repeated exposure to aerosolized OVA. The effects of daily administered curcumin (200mg/kg body weight, i.p.) on airway hyper-responsiveness (AHR), inflammatory cell number, and IgE levels in bronchoalveolar lavage (BAL) fluid were analyzed. NF-κB activation in lung tissue was also assessed by Western blot analyses. RESULTS: Curcumin inhibited NF-κB-dependent transcription in reporter assays in A549 cells with an IC(50) of 21.50±1.25µM. Curcumin stabilized IκBα and inhibited nuclear translocation of p65 and p50 in LPS-activated Raw264.7 cells, and curcumin-treated mice showed reduced nuclear translocation of p65 in lung tissue. Treatment with curcumin significantly attenuated AHR and reduced the numbers of total leukocytes and eosinophils in BAL fluid. Infiltration of inflammatory cells and mucus occlusions in lung tissue were significantly ameliorated by treatment with curcumin, which also markedly decreased the level of IgE in BAL fluid. CONCLUSION: Curcumin attenuates the development of allergic airway inflammation and hyper-responsiveness, possibly through inhibition of NF-κB activation in the asthmatic lung tissue. Our results indicate that curcumin may attenuate development of asthma by inhibition of NF-κB activation.

Ectomycorrhizal fungal communities associated with Pinus thunbergii in the eastern coastal pine forests of Korea.

We investigated the ectomycorrhizal (ECM) fungal colonization status of Pinus thunbergii mature trees and regenerating seedlings varying in age in coastal pine forests on the east coast of Korea. We established one 20 x 20-m plot at each of two study sites at P. thunbergii coastal forests in Samcheok. Fifty soil blocks (5 x 5 x 15 cm) were sampled at regular intervals, and ten P. thunbergii seedlings of age 0, 1-3, 3-5, and 5-10 years were sampled in each study plot. In total of 27 ECM fungal taxa, Cenococcum geophilum was dominant, followed by Russula sp., Sebacina sp., and unidentified Cortinuris sp. in mature trees. In 0-year-old seedlings, some fungal species such as Sebacina sp., C. geophilum, and unidentified Cortinarius sp. were dominant whereas only C. geophilum was dominant after 1 year, and there were no apparent succession patterns in ECM fungal compositions beyond a host age of 1 year. Most ECM fungal taxa that had colonized seedlings of each age class were also observed in roots of mature trees in each site. These taxa accounted for 86.7-100% and 96.4-98.4% of ECM abundance in seedlings and mature trees, respectively. The results indicate that the species composition of ECM fungal taxa colonizing seedlings of different age in forests is similar to that of surrounding mature trees. Our results also showed that C. geophilum is a common and dominant ECM fungus in P. thunbergii coastal forests and might play a significant role in their regeneration.

Potential inhibition of PDK1/Akt signaling by phenothiazines suppresses cancer cell proliferation and survival.

3'-Phosphoinositide-dependent kinase-1 (PDK1) has been identified for its ability to phosphorylate and activate Akt. Accumulated studies have shown that the activation of the PDK1/Akt pathway plays a pivotal role in cell survival, proliferation, and tumorigenesis. Therefore, the PDK1/Akt pathway is believed to be a critical target for cancer intervention. In this paper, we report the discovery of a new function of phenothiazines, widely known as antipsychotics, inhibiting PDK1/Akt pathway. Upon epidermal growth factor (EGF) stimulation, phenothiazines specifically suppressed the kinase activity of PDK1 and the phosphorylation level of Akt. The inhibition of PDK1/Akt kinase resulted in suppression of EGF-induced cell growth and induction of apoptosis in human ovary cancer cells. In particular, phenothiazines were highly selective for downstream targets of PDK1/Akt and did not inhibit the activation of phosphatidylinositol 3-kinase (PI3K), EGFR, or extracellular signal-regulated kinase 1/2 (ERK1/2). In particular, phenothiazines effectively suppressed tumor growth in nude mice of human cancer cells. Taken together, these findings provide strong evidence for novel function of phenothiazines, pharmacologically targeting PDK1/Akt for anticancer drug discovery.

Hydrolysis of ATP by aminoglycoside 3'-phosphotransferases: an unexpected cost to bacteria for harboring an antibiotic resistance enzyme.

Aminoglycoside 3'-phosphotransferases (APH(3')s) are common bacterial resistance enzymes to aminoglycoside antibiotics. These enzymes transfer the gamma-phosphoryl group of ATP to the 3'-hydroxyl of the antibiotics, whereby the biological activity of the drugs is lost. Pre-steady-state and steady-state kinetics with two of these enzymes from Gram-negative bacteria, APH(3')-Ia and APH(3')-IIa, were performed. It is demonstrated that these enzymes in both ternary and binary complexes facilitate an ATP hydrolase activity (ATPase), which is competitive with the transfer of phosphate to the antibiotics. Because these enzymes are expressed constitutively in resistant bacteria, the turnover of ATP is continuous during the lifetime of the organism both in the absence and the presence of aminoglycosides. Concentrations of the enzyme in vivo were determined, and it was estimated that in a single generation of bacterial growth there exists the potential that this activity would consume as much as severalfold of the total existing ATP. Studies with bacteria harboring the aph(3')-Ia gene revealed that bacteria are able to absorb the cost of this ATP turnover, as ATP is recycled. However, the cost burden of this adventitious activity manifests a selection pressure against maintenance of the plasmids that harbor the aph(3')-Ia gene, such that approximately 50% of the plasmid is lost in 1500 bacterial generations in the absence of antibiotics. The implication is that, in the absence of selection, bacteria harboring an enzyme that catalyzes the consumption of key metabolites could experience the loss of the plasmid that encodes for the given enzyme.

The dextromethorphan analog dimemorfan attenuates kainate-induced seizures via sigma1 receptor activation: comparison with the effects of dextromethorphan.

In a previous study, we demonstrated that a dextromethorphan analog, dimemorfan, has neuroprotective effects. Dextromethorphan and dimemorfan are high-affinity ligands at sigma1 receptors. Dextromethorphan has moderate affinities for phencyclidine sites, while dimemorfan has very low affinities for such sites, suggesting that these sites are not essential for the anticonvulsant actions of dimemorfan. Kainate (KA) administration (10 mg kg(-1), i.p.) produced robust convulsions lasting 4-6 h in rats. Pre-treatment with dimemorfan (12 or 24 mg kg(-1)) reduced seizures in a dose-dependent manner. Dimemorfan pre-treatment also attenuated the KA-induced increases in c-fos/c-jun expression, activator protein (AP)-1 DNA-binding activity, and loss of cells in the CA1 and CA3 fields of the hippocampus. These effects of dimemorfan were comparable to those of dextromethorphan. The anticonvulsant action of dextromethorphan or dimemorfan was significantly counteracted by a selective sigma1 receptor antagonist BD 1047, suggesting that the anticonvulsant action of dextromethorphan or dimemorfan is, at least in part, related to sigma1 receptor-activated modulation of AP-1 transcription factors. We asked whether dimemorfan produces the behavioral side effects seen with dextromethorphan or dextrorphan (a phencyclidine-like metabolite of dextromethorphan). Conditioned place preference and circling behaviors were significantly increased in mice treated with phencyclidine, dextrorphan or dextromethorphan, while mice treated with dimemorfan showed no behavioral side effects. Our results suggest that dimemorfan is equipotent to dextromethorphan in preventing KA-induced seizures, while it may lack behavioral effects, such as psychotomimetic reactions.