THE PHARMACOLOGICAL ROLE OF P-GLYCOPROTEIN IN THE INTESTINAL EPITHELIUM

P-glycoprotein, a membrane-associated transport protein, has recently been recognised as an important element of the intestinal epithelium. This paper summarises thein vivodata on the pharmacological role of intestinal P-glycoprotein. These data show that P-glycoprotein contributes to the elimination of many drugs by mediating their direct secretion from the blood into the intestinal lumen. In addition, there is also evidence that this protein can limit oral drug absorption. Hence, inhibition of intestinal P-glycoprotein, e.g. by a reversal agent like cyclosporin A, may be a promising strategy for improving the oral bioavailability of P-glycoprotein substrate drugs. Indeed, several preclinical and clinical studies have shown that coadministration of drugs with a reversal agent can substantially increase oral drug absorption.     

34例淋巴瘤骨髓浸润患者治疗与预后分析

目的 探讨淋巴瘤骨髓浸润患者的治疗与预后。方法 34例淋巴瘤骨髓浸润患者分为单纯化疗组、化疗+放疗组、大剂量化疗+自体干细胞移植组进行治疗,长期随访,分析其预后状况。结果 全组中位生存期为20个月;1年和3年生存率分别为76.47％和26.47％,最初疗效为完全缓解和部分缓解患者的1年和3年生存率均大于未缓解患者(P<0.05);大剂量化疗+自体干细胞移植组的3年生存率大于单纯化疗组和化疗+放疗组(P<0.05)。结论 淋巴瘤骨髓浸润患者的生存率与最初疗效有关;大剂量化疗+自体干细胞移植能提高其生存率,改善预后。     

Mechanisms and patient compliance of dust-mite avoidance regimens in dwellings of mite-allergic rhinitic patients

We report on the mechanisms, the environmental changes and patient compliance with regard to conventional and new dust and mite avoidance measures to prevent allergic symptoms caused by mite allergens, taking into account both allergen contamination and the developmental success of pyroglyphid Acari. Twenty patients with persisting rhinitic complaints were selected and matched. Although the patients had performed some conventional dust and mite avoidance measures (patient compliance was 90%), the dwellings proved to be a stimulus for mite development. Moisture problems due to faulty construction and excessive moisture production were common. Since humidity conditions could not be changed at short notice, the 20 homes were subjected to the new variants of mite allergen avoidance based on intensive cleaning without (control) and with an acaricide incorporated (acaricidal cleaner [Acarosan]). After the carrying out of conventional avoidance measures, these patients still had allergic symptoms, and dust from only 23 to 52% of their textile objects was under the proposed guanine (mite faeces indicator) risk level. Only the acaricidal cleaner was able to decrease the allergenic mite load (and the burden of the patients) significantly in this 12 month period. With respect to mite-extermination, acaricidal cleaning was 88% better than intensive cleaning. Reduction of guanine was 38% better in the Acarosan treatment group. Clinical results have been reported elsewhere. A significant difference in favour of the acaricidal cleaning was seen in both subjective (as regards symptoms) and in objective data (total IgE). Another 50 patients were questioned. About 90% were willing to spend two weekends (70%), or at the most one weekend (20%) per year sanitizing the dwelling by cleaning it with the whole family. The authors of this report consider acaricidal cleaning to be a significant improvement in the management of mite-allergic diseases, such as rhinitis. Compared with the replacement of home textiles, this treatment is less expensive and more effective. Patient compliance is acceptable, but depends on acceptance by physicians and the initial motivation and consequent burden on the patient.     

Autoimmune reactions in patients with M-component and peripheral neuropathy.

A study of 17 patients with autoimmune axonal or demyelinating peripheral neuropathy in combination with M-component is described. The M-component was associated with MGUS (monoclonal gammopathy of undetermined significance) in 12 patients, CLL in one patient, WaldenstrÖm's disease in one patient, and myeloma in three patients. Immunohistological examination with direct and indirect fluorescence showed binding of antibodies to nerve structures of the same class and light chain as seen in the M-component. In five cases of IgM M-component, the demyelinating neuropathy was caused by binding of the IgM M-protein and complement C3b to myelin-associated glycoproteins (MAG). In 12 cases with axonal neuropathy, binding of IgG to the connective tissue of the peri- and endoneurium was found in 50% of cases, IgM in five cases, and IgD in one case. None of the patients had central nervous system (CNS) symptoms. The clinical and therapeutic difficulties are discussed; only two patients with an acute course responded to immunosuppression. A marked co-expression of other autoimmune phenomena is interpreted in the light of cross-reactions between the autoantibody and similar tissue autoantigens.     

Characterization of antibody and selection of alternative drug therapy in hydrochlorothiazide-induced immune hemolytic anemia

The authors report the clinical and laboratory findings of a patient who had severe immune hemolytic anemia due to hydrochlorothiazide (HCTZ). In this case, the HCTZ antibody reacted not only with other thiazide and thiazide-like drugs, but also with a chemically unrelated diuretic, ethacrynic acid. These results indicate that HCTZ antibody activity is not restricted solely to the thiazides and imply that therapy with any of the reactive drugs would be contraindicated for this patient. The serologic screening for drug reactivity may be useful for selecting alternative therapy for patients with drug-induced immune hemolytic anemia.     

Frusemide and Its Acyl Glucuronide Show a Short and Long Phase in Elimination Kinetics and Pharmacodynamic Effect in Man

The pharmacokinetics of 80 mg frusemide given orally were investigated in normal subjects using a direct HPLC method for parent drug and its acyl glucuronide conjugate. Two half-lives could be distinguished in the plasma elimination of both frusemide and its conjugate, with values of 1.25 ± 0.75 and 30.4 ± 11.5 h for frusemide and 1.31 ± 0.60 and 33.2 ± 28.0 h for the conjugate. The renal excretion rate-time profile showed two phases; the rapid elimination phase lasted from 0–15 h and the second and slow phase, from 15–96 h. During the first 15 h, 33.3 ± 4.8% of the dosed frusemide was excreted; in the remaining period 15–96 h, 4.6 ± 1.5% was excreted. In the same two periods the excretion of the glucuronide was 13.4 ± 4.7 and 1.9 ± 1.1%, respectively. The mean renal clearance of frusemide was 90.2 ± 16.9 mL min^?1 during the first period and 91.5 ± 29.3 mL min^?1 in the remaining period, during which the stimulation of urine production was absent. The renal clearance of the acyl glucuronide was 702 ± 221 mL min^?1 in the first period, but only 109 ± 51.0 mL min^?1 in the second period. The stimulated urine production in the first 6 h after administration amounted to 2260 ± 755 mL (measured urine production minus baseline value of 1 mL min^?1 (360 mL). During the second or rebound period (6–96 h after drug administration), the quantity of urine was 990 ± 294 mL lower than what would have been expected from the baseline production of 5400 mL. This reduced production (0.82 mL min^?1) is equivalent to an 18% reduction in the average urine flow rate of 1 mL min^?1.     

Effect of adiposity on plasma lipid transfer protein activities: a possible link between insulin resistance and high density lipoprotein metabolism

Abstract. The mechanisms responsible for the decreased high density lipoprotein (HDL) cholesterol levels associated with obesity and insulin resistance are not well understood. Lecithin: cholesterol acyltransferase (LCAT) and cholesterol ester transfer protein (CETP) are key factors in the esterification of cholesterol in HDL and the subsequent transfer of cholesteryl ester towards apolipoprotein B-containing lipoproteins. Phospholipid transfer protein (PLTP) may be involved in the regulation of HDL particle size. We therefore measured the activities of LCAT, CETP and PLTP using exogenous substrate assays, as well as lipids, lipoproteins, insulin and C-peptide in fasting plasma from eight healthy obese men (body mass index >27 kg m^-2) and 24 non-obese subjects. The obese men had lower levels of HDL cholesterol (P<0·05) and higher levels of plasma triglycerides (P<0·05), insulin (P<0·05) and C-peptide (P<0·01), as compared to the quartile of subjects with the lowest body mass index (BMI <22·4 kg m^-2). CETP and PLTP activities were elevated in the obese men by 35% (P<0·01) and by 15% (P<0·05), respectively. LCAT activity was comparable among the quartiles. Linear regression analysis showed that CETP activity was positively correlated with body mass index (P<0·02), fasting blood glucose (P7lt;0·05) and plasma C-peptide (P<0·05). PLTP activity was positively related to body mass index (P<0·01), waist to hip circumference ratio (P<0·001), as well as to fasting blood glucose (P<0·05) and plasma C-peptide (P<0·05) It is concluded that the activities of CETP and PLTP are influenced by adiposity and possibly by insulin resistance. Elevated lipid transfer protein activities may provide a mechanism that contributes to alterations in HDL in insulin resistant states.