Mechanism of multidrug recognition by MDR1/ABCB1

MDR1/ABCB1, a member of the ABC group of proteins, is clinically important because it is not only involved in multidrug resistance in cancer but also affects the pharmacokinetic properties of various drugs. The most puzzling feature of MDR1 is that it recognizes and transports such a wide variety of substrates. In the present review, the function of MDR1 is compared with that of other ABC proteins, particularly MDR2/ABCB4, to understand the mechanism of drug recognition and transport by MDR1. MDR2, the amino acid sequence of which has 86% similarity to that of MDR1, excretes phosphatidylcholine and cholesterol in the presence of bile salts. ABCA1 transfers phospholipids, preferentially phosphatidylcholine, and cholesterol to lipid-free apoA-I to generate pre-beta-HDL, and ABCG1 excretes phospholipids, preferentially sphingomyelin, and cholesterol. Cholesterol also binds directly to MDR1 and modulates substrate recognition by MDR1. Cholesterol may fill the empty space of the drug-binding site and aid the recognition of small drugs, and facilitates the ability of MDR1 to recognize compounds with various structures and molecular weights. Eukaryote ABC proteins may retain similar substrate binding pockets and move bound substrates in an ATP-dependent manner. The prototype of eukaryote ABC proteins might be those involved in membrane lipid transport.

Essential role of neuron-enriched diacylglycerol kinase (DGK), DGKbeta in neurite spine formation, contributing to cognitive function

BACKGROUND

Diacylglycerol (DG) kinase (DGK) phosphorylates DG to produce phosphatidic acid (PA). Of the 10 subtypes of mammalian DGKs, DGKbeta is a membrane-localized subtype and abundantly expressed in the cerebral cortex, hippocampus, and caudate-putamen. However, its physiological roles in neurons and higher brain function have not been elucidated.

METHODOLOGY/PRINCIPAL FINDINGS

We, therefore, developed DGKbeta KO mice using the Sleeping Beauty transposon system, and found that its long-term potentiation in the hippocampal CA1 region was reduced, causing impairment of cognitive functions including spatial and long-term memories in Y-maze and Morris water-maze tests. The primary cultured hippocampal neurons from KO mice had less branches and spines compared to the wild type. This morphological impairment was rescued by overexpression of DGKbeta. In addition, overexpression of DGKbeta in SH-SY5Y cells or primary cultured mouse hippocampal neurons resulted in branch- and spine-formation, while a splice variant form of DGKbeta, which has kinase activity but loses membrane localization, did not induce branches and spines. In the cells overexpressing DGKbeta but not the splice variant form, DGK product, PA, was increased and the substrate, DG, was decreased on the plasma membrane. Importantly, lower spine density and abnormality of PA and DG contents in the CA1 region of the KO mice were confirmed.

CONCLUSIONS/SIGNIFICANCE

These results demonstrate that membrane-localized DGKbeta regulates spine formation by regulation of lipids, contributing to the maintenance of neural networks in synaptic transmission of cognitive processes including memory.

Bile salt-dependent efflux of cellular phospholipids mediated by ATP binding cassette protein B4

Human ABCB4 (multidrug resistance [MDR]3 P-glycoprotein) is expressed in the canalicular membrane of the hepatocyte. ABCB4 has been shown to be required for phosphatidylcholine (PC) secretion into the bile and to translocate PC across the plasma membrane. To further investigate the function of ABCB4, we established a cell line stably expressing ABCB4 (human embryonic kidney [HEK]/ABCB4). The efflux of phospholipids from HEK/ABCB4 cells was remarkably increased by the addition of taurocholate. In addition, the cholesterol efflux from HEK/ABCB4 cells was also enhanced in the presence of taurocholate. Light scattering measurements suggested that the taurocholate monomer plays an important role in ABCB4-mediated lipid secretion. On the other hand, the efflux of phospholipids and cholesterol was not mediated by ABCB1 (MDR1) even in the presence of taurocholate. Taurocholate promoted the efflux of phospholipids and cholesterol from HEK/ABCB4 cells more efficiently than glycocholate and cholate. ABCB4-K435M and ABCB4-K1075M, Walker A lysine mutants, did not mediate the phospholipid and cholesterol efflux in the presence of taurocholate, suggesting that ATP hydrolysis is essential for the efflux. Verapamil completely inhibited the taurocholate-dependent efflux of phospholipids and cholesterol from HEK/ABCB4 cells. Mass spectrometry revealed that, in the presence of taurocholate, HEK/ABCB4 cells preferentially secreted PC compared to sphingomyelin. PC vesicles induced cholesterol diffusion from cell membrane, but did not accept cholesterol from ABCB4.

CONCLUSION

ABCB4 mediates the efflux of phospholipids into the canalicular lumen in the presence of bile salts, and plays a crucial role in bile formation and lipid homeostasis.

Make-Up Therapy for Patients With Facial Nerve Palsy

Objectives:

To investigate the effectiveness of make-up therapy for patients with facial nerve palsy.

Methods:

Seven female patients with facial nerve palsy who received specialist make-up therapy were enrolled. The objective of the make-up therapy was to obtain a symmetrical facial appearance.

Results:

Overall score for the Facial Clinimetric Evaluation (FaCE) scale was significantly improved after make-up therapy. There was a tendency for symptoms of depression to be improved among patients after make-up therapy.

Conclusion:

Make-up therapy to improve the symmetry of facial appearance could afford a noninvasive and low-cost treatment for patients with facial nerve palsy, especially in terms of patient quality of life and psychological condition.

Enzymatic measurement of phosphatidic acid in cultured cells

In this work, we developed a novel enzymatic method for measuring phosphatidic acid (PA) in cultured cells. The enzymatic reaction sequence of the method involves hydrolysis of PA to produce glycerol-3-phosphate (G3P), which is then oxidized by G3P oxidase to generate hydrogen peroxide. In the presence of peroxidase, hydrogen peroxide reacted with Amplex Red to produce highly fluorescent resorufin. We found that lipase from Pseudomonas sp. can completely hydrolyze PA to G3P and FAs. The calibration curve for PA measurement was linear between 20 and 250 microM, and the detection limit was 5 microM (50 pmol in the reaction mixture). We also modified the method for the enzymatic measurement of lysophosphatidic acid. By this new method, we determined the PA content in the lipid extract from HEK293 cells. The cellular content of PA was decreased with increasing cell density but not correlated with the proliferation rate. The diacylglycerol kinase inhibitor R59949 markedly reduced the cellular PA content, suggesting the diacylglycerol kinase activity was involved in a large part of the PA production in HEK293 cells. This novel method for PA quantification is simple, rapid, specific, sensitive, and high-throughput and will help to study the biological functions of PA and its related enzymes.

Molecular mechanisms for biliary phospholipid and drug efflux mediated by ABCB4 and bile salts

On the canalicular membranes of hepatocytes, several ABC transporters are responsible for the secretion of bile lipids. Among them, ABCB4, also called MDR3, is essential for the secretion of phospholipids from hepatocytes into bile. The biliary phospholipids are associated with bile salts and cholesterol in mixed micelles, thereby reducing the detergent activity and cytotoxicity of bile salts and preventing cholesterol crystallization. Mutations in the ABCB4 gene result in progressive familial intrahepatic cholestasis type 3, intrahepatic cholestasis of pregnancy, low-phospholipid-associated cholelithiasis, primary biliary cirrhosis, and cholangiocarcinoma. In vivo and cell culture studies have demonstrated that the secretion of biliary phospholipids depends on both ABCB4 expression and bile salts. In the presence of bile salts, ABCB4 located in nonraft membranes mediates the efflux of phospholipids, preferentially phosphatidylcholine. Despite high homology with ABCB1, ABCB4 expression cannot confer multidrug resistance. This review summarizes our current understanding of ABCB4 functions and physiological relevance, and discusses the molecular mechanism for the ABCB4-mediated efflux of phospholipids.

Menopause, but not age, is an independent risk factor for fasting plasma glucose levels in nondiabetic women

OBJECTIVE

Glucose metabolism is influenced by various genetic and environmental factors. In women the prevalence of abnormal glucose metabolism is known to increase around and after age 50. The aim of this study was to determine whether menopause augments fasting plasma glucose (FPG) levels in women.

DESIGN

Of 672 Japanese women who underwent health examinations, we studied 505 nondiabetic participants who had no history of hysterectomy and had never used estrogens or progestins. All participants were administered an oral glucose tolerance test, and their blood measurements and information about their menopause status were obtained.

RESULTS

Of these 505 women, 208 were premenopausal and 297 were postmenopausal. Age, body mass index, triglycerides level, total cholesterol level, low-density lipoprotein cholesterol level, blood pressure, and homeostasis model assessment insulin sensitivity index rose across quintiles of FPG levels, whereas high-density lipoprotein cholesterol level and homeostasis model assessment pancreatic beta-cell function index did not. The number of premenopausal women declined and the number of postmenopausal women increased across quintiles of FPG levels. Univariate regression analysis demonstrated that age, body mass index, triglycerides level, low-density lipoprotein cholesterol level, and menopause status were associated with FPG level, whereas high-density lipoprotein cholesterol level was not. Stepwise multivariate regression analysis showed that the independent risk factors for elevated FPG levels were body mass index, menopause, and triglycerides level, whereas age and low-density lipoprotein cholesterol level did not contribute to FPG levels.

CONCLUSIONS

Menopause, but not age, is directly involved in augmented FPG levels in nondiabetic women.

Efficient topical delivery of chlorogenic acid by an oil-in-water microemulsion to protect skin against UV-induced damage

We examined the intradermal delivery of a hydrophilic polyphenol chlorogenic acid by in vitro study using excised guinea pig dorsal skin and Yucatan micropig skin. Skin accumulation as well as the solubility of chlorogenic acid in aqueous vehicles was much greater than for other polyphenols such as quercetin and genistein. However, since enhancement of skin delivery seemed to be necessary to exhibit its protective effects against oxidative damage of skin, we examined the effects of microemulsions as vehicles. Using microemulsions consisting of 150 mM NaCl solution, isopropyl myristate, polyoxyethylene sorbitan monooleate (Tween 80) and ethanol, skin accumulation as well as solubility of chlorogenic acid further increased. Enhancement effect of an oil-in-water (o/w-type) microemulsion was greater than that of a water-in-oil (w/o-type) microemulsion possibly due to the greater increase in solubility. This finding was quite different from previous findings on relatively hydrophobic polyphenols such as quercetin and genistein. Pretreatment of guinea pig dorsal skin with chlorogenic acid containing microemulsion gel prevented erythema formation induced by UV irradiation. These findings indicate the potential use of hydrophilic chlorogenic acid with o/w-type microemulsion as a vehicle to protect skin against UV-induced oxidative damage.

Human Adrenocortical Remodeling Leading to Aldosterone-Producing Cell Cluster Generation

Background. The immunohistochemical detection of aldosterone synthase (CYP11B2) and steroid 11β-hydroxylase (CYP11B1) has enabled the identification of aldosterone-producing cell clusters (APCCs) in the subcapsular portion of the human adult adrenal cortex. We hypothesized that adrenals have layered zonation in early postnatal stages and are remodeled to possess APCCs over time. Purposes. To investigate changes in human adrenocortical zonation with age. Methods. We retrospectively analyzed adrenal tissues prepared from 33 autopsied patients aged between 0 and 50 years. They were immunostained for CYP11B2 and CYP11B1. The percentage of APCC areas over the whole adrenal area (AA/WAA, %) and the number of APCCs (NOA, APCCs/mm²) were calculated by four examiners. Average values were used in statistical analyses. Results. Adrenals under 11 years old had layered zona glomerulosa (ZG) and zona fasciculata (ZF) without apparent APCCs. Some adrenals had an unstained (CYP11B2/CYP11B1-negative) layer between ZG and ZF, resembling the rat undifferentiated cell zone. Average AA/WAA and NOA correlated with age, suggesting that APCC development is associated with aging. Possible APCC-to-APA transitional lesions were incidentally identified in two adult adrenals. Conclusions. The adrenal cortex with layered zonation remodels to possess APCCs over time. APCC generation may be associated with hypertension in adults.

Immunohistochemistry of aldosterone synthase leads the way to the pathogenesis of primary aldosteronism

Our group previously purified human and rat aldosterone synthase (CYP11B2 and Cyp11b2, respectively) from their adrenals and verified that it is distinct from steroid 11β-hydroxylase (CYP11B1 or Cyp11b1), the cortisol- or corticosterone-synthesizing enzyme. We now describe their distributions immunohistochemically with specific antibodies. In rats, there is layered functional zonation with the Cyp11b2-positive zona glomerulosa (ZG), Cyp11b1-positive zona fasciculata (ZF), and Cyp11b2/Cyp11b1-negative undifferentiated zone between the ZG and ZF. In human infants and children (<12 years old), the functional zonation is similar to that in rats. In adults, the adrenal cortex remodels and subcapsular aldosterone-producing cell clusters (APCCs) replace the continuous ZG layer. We recently reported possible APCC-to-APA transitional lesions (pAATLs) in 2 cases of unilateral multiple adrenocortical micro-nodules. In this review, we present 4 additional cases of primary aldosteronism, from which the extracted adrenals contain pAATLs, with results of next generation sequencing for these lesions. Immunohistochemistry for CYP11B2 and CYP11B1 has become an important tool for the diagnosis of and research on adrenocortical pathological conditions and suggests that APCCs may be the origin of aldosterone-producing adenoma.

Effects of sphingomyelin on apolipoprotein E- and lipoprotein lipase-mediated cell uptake of lipid particles

It has been reported that human plasma sphingomyelin (SM) levels are positively and independently related to coronary artery disease. The lipoprotein surface is mainly formed by phosphatidylcholine (PC) and SM together with cholesterol and apolipoproteins. However, the influence of SM on the cell uptake of triglyceride-rich lipoproteins and remnants is poorly understood. To clarify the role of SM in lipoprotein uptake, we prepared lipid emulsions containing triolein, PC and SM as model particles of lipoproteins. Apolipoprotein E (ApoE) binding studies revealed that incorporation of SM into the emulsion surface reduced the binding capacity of apoE without changing the affinity. Surface SM reduced apoE-mediated uptake of emulsions by HepG2 cells because of the decreased amount of binding apoE. Apolipoproteins C-II and C-III inhibited the apoE-mediated uptake of SM containing emulsions more effectively. The stimulatory effect of lipoprotein lipase (LPL) on emulsion uptake was decreased by replacing surface PC with SM. These results suggest that SM-induced changes in the binding properties of apolipoproteins and LPL correlate with decreased hepatic uptake of lipid particles.

OTOF mutation analysis with massively parallel DNA sequencing in 2,265 Japanese sensorineural hearing loss patients

The OTOF gene (Locus: DFNB9), encoding otoferlin, is reported to be one of the major causes of non-syndromic recessive sensorineural hearing loss, and is also reported to be the most common cause of non-syndromic recessive auditory neuropathy spectrum disorder (ANSD). In the present study, we performed OTOF mutation analysis using massively parallel DNA sequencing (MPS). The purpose of this study was to reveal the frequency and precise genetic and clinical background of OTOF-related hearing loss in a large hearing loss population. A total of 2,265 Japanese sensorineural hearing loss (SNHL) patients compatible with autosomal recessive inheritance (including sporadic cases) from 53 otorhinolaryngology departments nationwide participated in this study. The mutation analysis of 68 genes, including the OTOF gene, reported to cause non-syndromic hearing loss was performed using MPS. Thirty-nine out of the 2,265 patients (1.72%) carried homozygous or compound heterozygous mutations in the OTOF gene. It is assumed that the frequency of hearing loss associated with OTOF mutations is about 1.72% of autosomal recessive or sporadic SNHL cases. Hearing level information was available for 32 of 39 patients with biallelic OTOF mutations; 24 of them (75.0%) showed profound hearing loss, 7 (21.9%) showed severe hearing loss and 1 (3.1%) showed mild hearing loss. The hearing level of patients with biallelic OTOF mutations in this study was mostly severe to profound, which is consistent with the results of past reports. Eleven of the 39 patients with biallelic OTOF mutations had been diagnosed with ANSD. The genetic diagnosis of OTOF mutations has significant benefits in terms of clinical decision-making. Patients with OTOF mutations would be good candidates for cochlear implantation; therefore, the detection of OTOF mutations is quite beneficial for patients, especially for those with ANSD.

WFS1 mutation screening in a large series of Japanese hearing loss patients: Massively parallel DNA sequencing-based analysis

A heterozygous mutation in the Wolfram syndrome type 1 gene (WFS1) causes autosomal dominant nonsyndromic hereditary hearing loss, DFNA6/14/38, or Wolfram-like syndrome. To date, more than 40 different mutations have been reported to be responsible for DFNA6/14/38. In the present study, WFS1 variants were screened in a large series of Japanese hearing loss (HL) patients to clarify the prevalence and clinical characteristics of DFNA6/14/38 and Wolfram-like syndrome. Massively parallel DNA sequencing of 68 target genes was performed in 2,549 unrelated Japanese HL patients to identify genomic variations responsible for HL. The detailed clinical features in patients with WFS1 variants were collected from medical charts and analyzed. We successfully identified 13 WFS1 variants in 19 probands: eight of the 13 variants were previously reported mutations, including three mutations (p.A684V, p.K836N, and p.E864K) known to cause Wolfram-like syndrome, and five were novel mutations. Variants were detected in 15 probands (2.5%) in 602 families with presumably autosomal dominant or mitochondrial HL, and in four probands (0.7%) in 559 sporadic cases; however, no variants were detected in the other 1,388 probands with autosomal recessive or unknown family history. Among the 30 individuals possessing variants, marked variations were observed in the onset of HL as well as in the presence of progressive HL and tinnitus. Vestibular symptoms, which had been rarely reported, were present in 7 out of 30 (23%) of the affected individuals. The most prevalent audiometric configuration was low-frequency type; however, some individuals had high-frequency HL. Haplotype analysis in three mutations (p.A716T, p.K836T, and p.E864K) suggested that the mutations occurred at these mutation hot spots. The present study provided new insights into the audiovestibular phenotypes in patients with WFS1 mutations.

Enzymatic measurement of phosphatidylserine in cultured cells

Phosphatidylserine (PS) is a quantitatively minor membrane phospholipid involved in diverse cellular functions. In this study, we developed a new fluorometric method for measuring PS using combinations of specific enzymes and Amplex Red. The calibration curve for PS measurement was linear and hyperbolic at low (0-50 µM) and high (50-1000 µM) concentrations, respectively, and the detection limit was 5 µM (50 pmol in the reaction mixture). This assay quantified PS regardless of the chain length and the number of double bonds. We applied this new method to the determination of PS content in HEK293 cells, which was validated by a recovery study and comparison with TLC-phosphorus assay. We showed that the PS content was high in sparse cells. The overexpression of PS synthase 1 elevated not only the cellular PS content but also the phosphatidylcholine (PC) and phosphatidylethanolamine (PE) contents, suggesting the conversion of PS into PE and the enhancement of PC production. This new assay for PS measurement is simple, specific, sensitive, and high throughput, and it will be useful to clarify the metabolism and biological functions of PS.

Novel action of apolipoprotein E (ApoE): ApoE isoform specifically inhibits lipid-particle-mediated cholesterol release from neurons

Background

Since the majority of apolipoprotein E (apoE) existing in the cerebrospinal fluid is associated with high-density lipoprotein (HDL), one should focus on the role of the apoE-HDL complex rather than on that of free apoE in cholesterol metabolism in the central nervous system. However, the apoE-isoform-specific effect of apoE-HDL on cholesterol transport remains unclarified.

Results

Here we show that apoE3-HDL induced a marked cholesterol release from neurons, while apoE4-HDL induced little. To elucidate the mechanism underlying this phenomenon, we used a complex of lipid emulsion (EM) with recombinant apoE3 or apoE4 (apoE-EM) at various apoE concentrations. When a small number of apoE molecules were associated with EM, apoE3- and apoE4-EM, induced a marked cholesterol release to a level similar to that induced by EM alone. However, when apoE at given concentrations was incubated with EM, apoE3-EM induced a marked cholesterol release, while apoE4-EM induced little. Under these conditions, a greater number of apoE4 molecules were associated with EM than apoE3 molecules. When an increasing number of apoE molecules were associated with EM, both apoE3-EM and apoE4-EM induced little cholesterol release. Preincubation with β-mercaptoethanol increased the number of apoE3 molecules associated with EM similar to that of apoE4 molecules, indicating that the presence (apoE3) or absence (apoE4) of intermolecular disulfide bond formation is responsible for the association of a greater number of apoE4 molecules to EM than apoE3 molecules.

Conclusion

These results suggest that although apoE and a lipid particle are lipid acceptors, when apoE and a lipid particle form a complex, apoE on the particle surface inhibits the lipid particle-mediated cholesterol release from cells in an apoE-concentration-dependent manner.

Enhanced skin delivery of genistein and other two isoflavones by microemulsion and prevention against UV irradiation-induced erythema formation

To improve the efficiency of the intradermal delivery of genistein and other two isoflavones (daidzein and biochanin A), we tried to clarify the usefulness of microemulsion by in vitro study on excised guinea pig dorsal skin and Yucatan micropig skin. Using microemulsion consisting of isopropyl myristate (IPM), 150 mM NaCl solution, Tween 80 and ethanol as a vehicle, the solubility of all the isoflavones markedly increased and significant amounts of isoflavones were delivered to the skin. The effect of water-in-oil (w/o)-type microemulsion D was larger than that of oil-in-water (o/w)-type microemulsion A. Among three isoflavones tested, the increase of genistein was most marked on both solubility and skin accumulation. Genistein retained in the skin significantly inhibited lipid peroxidation in vitro dose-dependently. Furthermore, pretreatment of guinea pig dorsal skin with genistein containing gel-like microemulsion D prevented UV irradiation-induced erythema formation. These findings indicate the potential use of w/o-type microemulsion for the delivery of genistein to protect skin against UV-induced oxidative damage.

Distribution of polyphenols and a surfactant component in skin during Aerosol OT microemulsion-enhanced intradermal delivery

As for most other polyphenols, intradermal delivery of curcumin and resveratrol is limited; however, it was significantly improved by a microemulsion using Aerosol OT (Aerosol OT microemulsion) and Tween 80 (Tween 80 microemulsion) as surfactants. Aerosol OT microemulsion was more effective and the incorporation ratio of these polyphenols into skin by Aerosol OT microemulsion was five-fold or ten-fold that by Tween 80 microemulsion. To clarify the mechanism of the enhancement we examined the distribution of these polyphenols and the surfactant component, Aerosol OT, using excised guinea pig skin and Yucatan micropig (YMP) skin. During permeation, polyphenols distributed deep in the skin. In particular, a small molecule, resveratrol, was mainly present in the dermis in YMP skin. Aerosol OT also distributed deep in the skin. These findings suggest the possible involvement of the interaction of surfactant molecules with skin components in the enhanced delivery process of polyphenols. The distribution ratio between the dermis and epidermis of the polyphenols, including quercetin, in the presence of Aerosol OT microemulsion decreased with the increase of molecular weight in YMP skin, suggesting the possibility that distribution to the dermis is regulated by the molecular size.

Otologic and Rhinologic Manifestations of Eosinophilic Granulomatosis with Polyangiitis

BACKGROUND

Eosinophilic granulomatosis with polyangiitis (EGPA) is a systemic autoimmune disease that manifests as asthma, recurrent sinusitis and peripheral eosinophilia. In this study, we investigated the clinical features of the ear and nasal manifestations of EGPA in comparison with those of granulomatosis with polyangiitis (GPA).

MATERIALS AND METHODS

Twenty-one patients diagnosed with EGPA were studied. The frequency of otologic manifestations, the degree of hearing loss and the frequency of nasal symptoms were assessed. The onset of ear symptoms, sinusitis and asthma in patients with EGPA were also examined.

RESULTS

Eleven patients (52.4%) with EGPA demonstrated otologic symptoms. The EGPA patients commonly presented mild-to-moderate mixed or sensorineural hearing loss. The pattern of hearing loss was mainly flat, and all but 1 patient achieved complete remission from their hearing impairments. Eighteen patients (85.7%) with EGPA demonstrated nasal symptoms. Patients with EGPA showed a significantly higher incidence of nasal polyps than did those with GPA. The median Lund and Mackey scoring system score was 13.7 for patients with EGPA, and ethmoid sinus shadows were more severe than those of the maxillary sinus. Most ear symptoms associated with EGPA were observed after definitive diagnosis, although sinusitis and asthma tended to manifest themselves before diagnosis. There were significant differences between the onset of ear symptoms and those of asthma and sinusitis.

CONCLUSION

As over 80% of patients with EGPA had nasal symptoms and over half had ear symptoms, otolaryngologists should be aware of this disease. Recognition of the characteristic ear and nasal symptoms are thought to be particularly important to obtain an early diagnosis of EGPA.

Comparison of annual variability in HbA1c and glycated albumin in patients with type 1 vs. type 2 diabetes mellitus

OBJECTIVE

It has been suggested that plasma glucose (PG) levels per se and long-term variations in PG levels are associated with diabetic vascular complications. Glycated albumin (GA) reflects shorter-term glycemic control, as well as postprandial PG levels, as compared to HbA1c. In this study, we hypothesized that GA more strongly reflects long-term variations in PG levels than HbA1c, and compared the variability of HbA1c and that of GA in patients with type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM).

METHODS

This study included 8 T1DM patients and 48 T2DM patients. Over a 1-year period, HbA1c and GA were measured every month and the mean values and coefficients of variation (CV) for each patient were calculated.

RESULTS

In both T1DM and T2DM patients, the CV of GA was significantly higher than the CV of HbA1c. Both the CV of HbA1c and the CV of GA were significantly higher in the T1DM patients than in the T2DM patients.

CONCLUSION

The annual variability in GA was greater than that in HbA1c. In addition, the annual variability in HbA1c and that in GA in the T1DM patients were greater than in the T2DM patients. Our findings suggest that GA more accurately reflects long-term variations in PG levels than HbA1c.

Predictive factors for severe and febrile neutropenia during docetaxel chemotherapy for castration-resistant prostate cancer

BACKGROUND

The aim of this study is to identify factors that increase the occurrence of severe neutropenia (SN) and febrile neutropenia (FN) during docetaxel treatment for castration-resistant prostate cancer (CRPC).

METHODS

We retrospectively reviewed 258 courses during the first three cycles among 95 patients. Docetaxel at a dose of 75 mg/m(2) was administered every 3 or 4 weeks. Patient background, laboratory data, and bone scan results were collected to assess predictive factors for SN and FN. We defined SN as an absolute neutrophil count (ANC) of <500/mm(3) and defined FN as an ANC of <1000/mm(3) with a body temperature of >38.3 °C.

RESULTS

The mean age of the patients was 72.6 ± 6.4 years and the mean prostate-specific antigen was 135.4 ± 290.9 ng/ml. During the first three courses of treatment, SN occurred in 72.6% of patients and FN occurred in 9.5 % of patients. Univariate analysis demonstrated that age ≥ 75 years (p = 0.002), number of comorbidities ≥ 1.2 (p = 0.008 and p = 0.006) and previous external beam radiation therapy (EBRT) (p = 0.001) were predictive factors for the development of SN or FN. In multivariate analysis, significant predictors of SN or FN were age ≥ 75 years (hazard ratio [HR] 5.77; p = 0.004) and previous EBRT (HR 14.5; p = 0.012). According to the subgroup analysis dividing SN and FN separately, multivariate analysis also revealed that age ≥ 75 years and previous EBRT were also significant predictors for developing SN (HR 5.09; p = 0.023, HR 12.7; p = 0.020, respectively) and for developing FN (HR 5.45; p = 0.042, HR 7.72; p = 0.015, respectively).

CONCLUSIONS

Patients aged ≥ 75 years and with a history of localized radiation therapy are at higher risk for significant neutropenic events and require closer surveillance.

Effects of plasma apolipoproteins on lipoprotein lipase-mediated lipolysis of small and large lipid emulsions

Large (ca. 120 nm) and small (ca. 35 nm) emulsions consisting of triolein (TO) and phosphatidylcholine (PC) were prepared as the primary protein-free models of chylomicrons and their remnants, respectively. Lipoprotein lipase (LPL)-mediated lipolysis of emulsion TO was retarded in chylomicron-free human plasma compared with the hydrolysis activated by isolated apolipoprotein C-II (apoC-II). In 30% plasma, free fatty acid (FFA) release rate was higher for large emulsions than for small ones, while both emulsions were hydrolyzed at similar rates in the presence of isolated apoC-II. Isolated apolipoprotein C-III (apoC-III) or apolipoprotein E (apoE) worked as LPL-inhibitor of the lipolysis activated by apoC-II. It was also observed that apolipoprotein A-I (apoA-I) showed distinct inhibitory effects on the lipolysis of large and small emulsions: more effective inhibition for small emulsions. Kinetic analyses showed that K(m)(app) and V(max)(app) for the lipolysis of emulsions were lower in the presence of 30% plasma than isolated apoC-II. ApoA-I also markedly decreased K(m)(app) and V(max)(app) for LPL-catalyzed hydrolysis of both emulsions. In chylomicron-free serum, the density of bound apoA-I at small emulsion surfaces was about three fold greater than large emulsion surfaces, but the binding densities of apoC-II, apoC-III and apoE were less for small emulsion surfaces than for large ones, suggesting that apoA-I preferentially binds to small particles and displaces other exchangeable apolipoproteins from particle surfaces. These results indicate that, in addition to the well known inhibitory effects of apoC-III and apoE, apoA-I in plasma regulates the lipolysis of triglyceride (TG)-rich emulsions and lipoproteins in a size-dependent manner.

Stool appearance in intussusception: assessing the value of the term "currant jelly"

This study surveyed the stool appearance descriptions of 107 inpatient children with intussusception. Fifty-six patients presented with grossly bloody stools (passed spontaneously), 10 of which were determined on chart review to resemble currant jelly. Of the 51 patients without grossly bloody spontaneously passed stools, 35 patients had rectal examination results charted. Eight of these children had grossly bloody stools noted on rectal examination, 4 of which were determined on chart review to resemble currant jelly. While most of the grossly bloody stools were not consistent with pure currant jelly, the most common terms used in describing the grossly bloody stools were "bloody," "mucus," "red," and "diarrhea." Since stools truly resembling currant jelly account for a minority of the grossly bloody stools in intussusception, the term "currant jelly stools" should be assessed in the teaching of intussusception. Generic terms such as blood, mucus, burgundy, red, etc, are more objective and sensitive at identifying cases of intussusception. Junior physicians who are taught the classic presentation of intussusception with currant jelly stool should also be taught that intussusception should be considered in the differential diagnosis of children passing any type of bloody stool. As a result, physicians with limited experience will be more likely to appropriately consider the diagnosis of intussusception, permitting a more timely diagnosis and a better outcome.