Enzymatic Hydrolysis of Zenarestat 1-O-Acylglucuronide

Abstract— Zenarestat, (3-(4-bromo-2-fluorobenzyl)-7-chloro-2,4-dioxo-1,2,3,4-tetrahydroquinazolin-1-y1) acetic acid, an aldose reductase inhibitor is metabolized mainly to the glucuronide in rat and man. The glucuronide was purified from urine of volunteers after ingestion of zenarestat. The structure of the glucuronide was confirmed by LC-MS and NMR as 1-O-acyl-β-glucuronide. This compound was unstable at physiological pH, being converted to its structural isomers and the aglycone with half-life of 25 min at pH 7·4 and 37°C in aqueous solution. Enzymatic hydrolysis of the glucuronide was studied in urine, blood and tissues. β-Glucuronidase in human urine contributed little to the hydrolysis of the glucuronide, while in rat urine at pH 6, it was degraded by β-glucuronidase and the formation of zenarestat was clearly faster than its formation in buffer at pH 6. In both rat and human blood, these reactions were accelerated by albumin, although rat red blood cells may also contribute. The rate of degradation was not affected by red blood cell membrane, haemoglobin, globulin, esterases or β-glucuronidase. Arylesterase in rat liver, arylesterase and acetylcholinesterase in the kidney, and β-glucuronidase in both tissues may contribute. Thus, enzymatic degradation of zenarestat 1-O-acyl-β-glucuronide is dependent not only on pH and temperature but also on species and the type of tissue or body fluid.     

Rate-Dependent Threshold Changes During Atrial Pacing: Clinical and Experimental Studies

In 36 patients undergoing a permanent right atrial pacing for the treatment of sick sinus syndrome and/or atrioventricular block, the stimulation threshold was determined at a wide range of pacing rates (60 to 120 beats/min) 7 to 10 days after the lead implantation. Twenty-nine (80%) of these cases showed rate-dependent threshold changes, with significantly lower thresholds at higher than lower pacing rates (e.g., 2.91 +/- 1.01 mA at 70 beats/min and 2.32 +/- 0.75 mA at 120 beats/min, P less than 0.01). Thus, with a fixed, smaller current strength, the stimuli often failed to capture the right atrium at lower rates, but caused a 1:1 capture at higher rates. In an echocardiographic study in another series of eight patients, the end-diastolic diameter of the left atrium was decreased from 3.2 +/- 0.9 to 2.7 +/- 0.8 cm (P less than 0.01) when the pacing rate was increased from 60-70 beats/min to 100-120 beats/min. In experiments using two anesthetized, open-chest dogs, a rapid withdrawal of 500 mL of arterial blood reduced the right atrial dimension. This was accompanied by an increased amplitude of the right atrial endocardial electrogram, and the initially subthreshold stimuli became effective in capturing the atria. It was concluded that (1) rate-dependent threshold changes were commonly observed in the early stage of atrial pacing, and (2) fluctuations in the electrode contact with the endocardium appeared responsible for such threshold changes.     

Distribution and Elimination of Sulphadimethoxine and Its Metabolites in Treated Chicken

Abstract— Sulphadimethoxine (SDM), and its metabolites, N₄-acetyl SDM, N₁-(2-methyl-6-hydroxy-4-pyrimidinyl) sulphanilamide (6-OH-SDM), N₁-(6-methyl-2-hydroxy-4-pyrimidinyl) sulphanilamide (2-OH-SDM), N₁-(2,6-dihydroxy-4-pyrimidinyl) sulphanilamide (2,6-diOH-SDM) and SDM N₁-glucuronide in chicken tissues were extracted, partially purified by Bond Elute SCX cartridges, and assayed and identified by HPLC/LC-MS after administration of SDM to chickens. During the administration and 24 h after withdrawal, SDM and 6-OH-SDM were observed in almost all tissues and excreta. N₄-Acetyl SDM and 2,6-diOH-SDM were observed in some tissues, but 2-OH-SDM and SDM N₁-glucuronide were observed in a few limited tissues. Twenty four hours after withdrawal, SDM and its metabolites, except 6-OH-SDM, decreased. SDM and its metabolites were eliminated from all tissues within 48 h of withdrawal.     

Effects of acupuncture for chronic pelvic pain syndrome with intrapelvic venous congestion: Preliminary results

BACKGROUND: The present study was designed to reveal the usefulness of acupuncture for chronic pelvic pain syndrome with intrapelvic venous congestion as evaluated by symptom scores, transrectal ultrasonography (TRUS) and magnetic resonance (MR) venography. METHODS: Ten male patients suffering from non-inflammatory chronic pelvic pain syndrome (NIH category IIIB) with intrapelvic venous congestion were treated using acupuncture. Eight patients had previously received pharmacotherapy, which was unsuccessful. Acupuncture was performed using disposable stainless steel needles, which were inserted into the bilateral BL-33 points and rotated manually for 10 min. The treatment was repeated every week for 5 weeks without other therapeutic maneuvers. Results from TRUS and MR venography, as well as clinical symptoms based on the NIH chronic prostatitis symptom index (NIH-CPSI) and the international prostate symptom score (IPSS), were compared before and after the treatment. RESULTS: No side-effects were recognized throughout the treatment period. The average pain and QOL scores of the NIH-CPSI 1 week after the 5th acupuncture treatment decreased significantly (P < 0.05 and P < 0.01, respectively) compared with the baseline. The maximum width of the sonolucent zone 1 week after the 5th treatment also decreased significantly (P < 0.01, compared with the baseline). Intrapelvic venous congestion demonstrated by MR venography was significantly improved in four patients. CONCLUSION: This study provided novel information concerning the therapeutic effects of acupuncture on non-inflammatory chronic pelvic pain syndrome.     

Echographic Detection of Latent Severe Thrombotic Stenosis of the Superior Vena Cava and Innominate Vein in Patients with a Pacemaker: Integrated Diagnosis Using Sonography, Pulse Doppler, and Color Flow

Thrombosis of the innominate vein and SVC is a serious complication in patients with pacemakers, inducing puhnonary embolism or SVC syndrome. Venography is the definitive method for its diagnosis; however, it is too invasive for related studies. The purpose of this study was to validate sonography, pulse Doppler, and color flow in detecting noninvasively innominate vein or SVC thrombosis in patients with pacemakers. In 53 patients with pacemakers, the 1 severe SVC stenosis and 18 severe innominate vein stenoses due to thrombosis were diagnosed by digital subtraction angiography. Sonography accurately showed the severe SVC stenosis due to thrombosis, but had limitations on the innominate vein thrombosis. Color flow demonstrated mosaic flow, indicating poststenotic turbulence due to stenosis of the innominate vein and SVC caused by thrombosis in 15 of 16 patients, and pulse Doppler disclosed absence of flow due to complete occlusion of the innominate vein in 2 of 2 patients. Sensitivity and specificity for detecting severe innominate vein stenosis due to thrombosis using combined color flow and pulse Doppler was 94% and 100%, respectively. In conclusion, sonography, pulse Doppler, and color flow allow accurate detection of severe innominate vein or SVC stenosis due to thrombosis, and are therefore useful for the follow-up of patients with a pacemaker.     

Isolation and characterization of two distinct gonadotropins,GTHI and GTHII,from bonito (Katsuwonus plelamis) pituitary glands

Two distinct glycoproteins homologous to chum salmon GTHI and GTHII were isolated from the pituitary glands of a marine fish, the bonito (Katsuwonus plelamis), and characterized by amino acid sequence analysis in order to obtain additional evidence for duality of teleost GTHs. Glycoproteins were extracted from the pituitary glands, and intact GTHI and GTHII, consisting of two distinct subunits, were purified by ion-exchange chromatography on DEAE-cellulose, rpHPLC an Asahipak C4P-50 in alkaline buffer, and gel filtration on Superdex 75. The association of the subunits was stable in GTHI (39 kD) and unstable in GTHII (30 kD) in acidic conditions. Immunoblotting revealed that antisera against β subunits of chum salmon GTHs reacted with GTHII, but not with GTHI. In addition, none of the GTHs was stained with antiserum against human TSHβ. Sequence analysis demonstrated that bonito GTHIβ is homologous to salmon GTHIβ with 43% sequence identity, and bonito GTHIIβis homologous to salmon GTHIIβ with 67% identity. Sequence identity between bonito GTHIβ and GTHIIβ was only 28%. Thus, it is evident that the bonito pituitary gland produces two chemically distinct gonadotropins homologous to chum salmon GTHs.     

Metastatic Bone Tumors: Diagnosis and Treatment

Seventy-four cases of metastatic bone tumors were reviewed inorder to study the actual problems concerning their diagnosisand treatment. Sixty-five of the 74 tumors were carcinoma metastasesand the remaining nine were other malignancies. Diagnosis: In our study, as has often been reported elsewhere,there was a high incidence of metastasis of lung and breastcancer (27% and 9%, respectively). In all patients in this series,the existence of bone metastasis itself was shown by plain radiogramsat the time of their admission. In 51 patients, primary siteswere identified by clinical records and/or various clinicalexaminations. Autopsy revealed additional seven primary sites. Treatment: Limb surgery which directly intends a resection ofthe metastatic lesion generally provided good palliation and,on occasion, relatively long survival. Of the seven patientswhose bone lesions were enthusiastically resected, three survivedfor 15, 27 and 36 months postoperatively and one has survivedup to the present (18 months). On the other hand, laminectomy and other procedures of vertebralsurgery which do not directly intend a resection did not givegood results in either quad vitam vol functionem. Twenty of21 patients died within a relatively short time (1 to 13 months,average 3.6 months) without any functional recovery.