Optimal Planning Target Margin for Prostate Radiotherapy Based on Interfractional and Intrafractional Variability Assessment during 1.5T MR-Guided Radiotherapy

PURPOSE/OBJECTIVE(S)

MR-guided radiotherapy (MRgRT) provides superior soft-tissue contrast over CT-based image guidance. We collected and analyzed daily pre-treatment (PRE) and real-time motion-monitoring (MM) MR images of patients receiving prostate radiotherapy to assess interfractional and intrafractional variability of prostate using two localization methods: pelvic bony anatomy (bone) and prostate during online adaptive radiotherapy (ART).

MATERIALS/METHODS

PRE and MM MRIs for the first five fractions of twenty prostate cancer patients who received definitive MRgRT with 1.5T MRI were collected. Using MIM software, rigid registration between PRE MRI and planning CT images based on pelvic bony anatomy and prostate reproduced bone localization and online ART, respectively. To determine interfractional setup margin (SM), prostate was delineated on all PRE MRIs registered after bone and prostate localizations by a radiation oncologist, and centroid values of prostate contours between planning CT and PRE MRIs were compared. To determine interobserver variability, another radiation oncologist, a medical physicist, and a radiotherapist contoured prostate for both localization methods. For internal margin (IM) assessment, we used MM MRIs of the five patients who had all three sets of coronal, sagittal, and axial cine images and determined the maximum contour displacement using in-house MATLAB-based software converting binary image files to 2D cine images with a superimposed grid of 1 mm spacing.

RESULTS

A total of 100 PRE and 25 MM MRIs were analyzed. Four hundred prostate contours were delineated on MR images registered with planning CT based on both bony anatomy and prostate. After bone localization, SM was 0.57±0.42 mm in left-right (LR), 2.45±1.98 mm in anterior-posterior (AP), and 2.28±2.08 mm in superior-inferior (SI) directions, and IO was 1.06±0.58 mm in LR, 2.32±1.08 mm in AP, and 3.30±1.85 mm in SI directions. After prostate localization, SM was 0.76±0.57 mm in LR, 1.89±1.60 mm in AP, and 2.2±1.79 mm in SI directions, and IO was 1.11±0.55 mm in LR, 2.13±1.07 mm in AP, and 3.53±1.65 mm in SI directions. Average IM was 2.12±0.86 mm, 2.24±1.07 mm, and 2.84±0.88 mm in LR, AP, and SI directions, respectively.

CONCLUSION

Using daily MRIs from MRgRT, we showed that movements in the SI direction were the largest source of variability in prostate definitive RT. In addition, interobserver variability was a non-negligible source of margin. Optimal PTV margin should also consider internal margin, especially in the SI direction.

Progression of Osteoporosis After Kidney Transplantation in Patients With End-Stage Renal Disease

BACKGROUND

This study investigated the prevalence of osteoporosis and the risk factors for its progression in kidney transplant recipients (KTRs).

METHODS

Dual energy X-ray absorptiometry was used to prospectively measure changes in bone mineral density (BMD) before kidney transplantation (KT) and 1 year after transplantation in 207 individuals. We also analyzed the risk factors of osteoporosis progression during this period.

RESULTS

Prior to KT, the mean BMD score (T-score of the femur neck area) was -2.1 ± 1.2, and the prevalence of osteoporosis was 41.5% (86/207). At 1 year post-transplantation, the mean BMD score significantly decreased to -2.3 ± 1.1 (P < .001), and the prevalence of osteoporosis increased to 47.3% (98/207; P = .277). The BMD score worsened over the study period in 69.1% (143/207) of patients, improved in 24.1% (50/207), and showed no change in 6.8% (14/207). Minimal intact parathyroid hormone (iPTH) improvement after KT was found to be an independent risk factor of osteoporosis progression.

CONCLUSIONS

This study demonstrates progressive loss of BMD after KT and sustained secondary hyperparathyroidism might influence the progression of osteoporosis.

Metabolomics Study for Identification of Potential Biomarkers of Long-term Survival in Kidney Transplantation Recipients

BACKGROUND

The recent progress and appropriate use of immunosuppressive drugs have considerably improved the short-term survival in kidney transplantation recipients (KTRs). The development of new strategies to improve long-term survival outcome after kidney transplantation is also becoming important. Although current diagnosis of allograft dysfunction relies on serum creatinine concentration and biopsy, they are nonspecific indicators of allograft function. Therefore, noninvasive, sensitive, and specific biomarkers for the prediction of long-term survival are needed. The aim of this study was to discover potential biomarkers for long-term survival in KTRs through the use of liquid chromatography-tandem mass spectrometry.

METHODS

We used the metabolic approach to explore the change of metabolites in the serum of KTRs. Twenty-four KTRs with long-term good survival (LGS) and 10 KTRs with chronic antibody-mediated rejection (CAMR) were included in this study. After quantile normalization with chromatographic data, multivariate statistical analysis was performed. We attempted to analyze metabolic profiling with LGS and CAMR groups.

RESULTS

The orthogonal partial least-squares discriminant analysis score plot showed a separation between 2 groups in the principal component. In the corresponding loading plot, 344 metabolites responsible for the separation observed in the score plot were identified (variable influence on projection ≥1.0). We then selected 54 metabolites to compare mass with charge by searching a web database, and 11 compounds were identified.

CONCLUSIONS

We found metabolites in serum that differ in LGS and CAMR groups. Further studies are needed to figure out potential metabolomic biomarkers to predict long-term survival in KTRs.

Effect of Empagliflozin on Tacrolimus-Induced Pancreas Islet Dysfunction and Renal Injury

An inhibitor of sodium glucose co-transporter type 2 (SGLT-2) is recommended in type 2 diabetes mellitus (DM) but its use is still undetermined in tacrolimus (TAC)-induced DM. We evaluated the effect of empagliflozin (Em) on TAC-induced pancreatic islet dysfunction and renal injury in an experimental model of TAC-induced DM and in vitro. TAC induced a twofold increase in SGLT-2 expression, while Em decreased SGLT-2 expression and further increased urinary glucose excretion compared to the TAC group. Em reduced hyperglycemia and increased plasma insulin level, pancreatic islet size, and glucose-stimulated insulin secretion compared to the TAC group. In kidney, Em alleviated TAC-induced renal dysfunction and decreased albumin excretion and histological injury compared with the TAC group. Increased oxidative stress and apoptotic cell death by TAC was remarkably decreased with Em in serum and pancreatic and renal tissues. In in vitro study, TAC decreased cell viability and increased reactive oxygen species (ROS) production in both insulin-secreting beta-cell derived (INS-1) and human kidney-2 (HK-2) cell lines. Addition of Em increased cell viability and decreased ROS production in HK-2 but not in INS-1 cell lines. This suggests that Em is effective in controlling TAC-induced hyperglycemia and has direct protective effect on TAC-induced renal injury.

Nanoembossed gold nanoshell with a fluorescence-like strong SERS signal

We present a nanoembossed nanoshell with a new internal location for the formation of strong electromagnetic fields. The internally nanoembossed gold nanoshell (AuNS) is fabricated by electrostatically assembling smaller silica nanoparticles (∼15.7 nm) around the silica core (∼123.6 nm) followed by growing gold nanoseeds on the core in a wet process. FDTD calculations reveal the creation of a strong electromagnetic field (|E/Ein|max = 55 at 633 nm) at sharp edges formed by the contact between the nanoembosses and the silica core. The field formation is supported by measuring the SERS signal of Ru(bpy) encapsulated in the nanoembossing silica nanoparticles. SERS signals as strong as the corresponding fluorescence are obtained. The Raman enhancement factor (EF) is estimated to be up to 10(10) at 633 nm excitation, in addition to a comparable EF at 785 nm laser excitation. The SERS intensity of the nanoembossed nanoshell layer is sufficiently high compared to the outer or the core of the nanoshell. Finally, we fabricate all-in-one nanoparticles with all the three places where the reporter dyes are loaded and acquire the highest SERS intensity to potentially enable bio-medical applications of the nanoembossed AuNS as a sensitive and reliable labeling particle.

Rate and associated factors of solifenacin add-on after tamsulosin monotherapy in men with voiding and storage lower urinary tract symptoms

AIM

To explore the rate of add-on therapy with solifenacin in men with voiding and storage lower urinary tract symptoms (LUTS) after tamsulosin monotherapy and to explore predictive factors for starting solifenacin add-on therapy.

METHODS

Men aged ≥ 45 years with IPSS ≥ 12 and symptoms of OAB (OAB-V8 ≥ 8, micturition ≥ 8/24 h, urgency ≥ 2/24 h) were enrolled to receive tamsulosin 0.2 mg once daily. After 4 weeks, men with residual symptoms of OAB and reported 'dissatisfied' or 'a little satisfied' were received solifenacin 5 mg in combination with tamsulosin monotherapy. Subjects completed an IPSS, a Quality of life (QoL) index, OAB V8, and an International Consultation of Incontinence Questionnaire (ICIQ)-Male LUTS, and patient perception of bladder condition (PPBC) at baseline and week 4.

RESULTS

Of a total of 305 patients, 254 patients completed 4 weeks of tamsulosin treatment. For 176 patients, solifenacin was added (69.3%). Significant predictive factors of solifenacin add-on therapy included long LUTS duration, high IPSS, number of micturitions per 24 h, more urgency episodes, high urgency severity score in a voiding diary and high OAB V8 score. Based on multivariable analysis, potential predictive factors of solifenacin add-on therapy included long LUTS duration (OR = 1.008, 95% CI: 1.001-1.014), high serum PSA (OR = 1.543, 95% CI: 1.136-2.095) and small prostate size (OR = 0.970, 95% CI: 0.947-0.994) (p < 0.05). IPSS, daytime micturitions and urgency episodes, OAB V8 scores, ICIQ and PPBC were improved after tamsulosin monotherapy.

CONCLUSIONS

Two thirds of men with voiding and storage LUTS needed to add anticholinergics after 4 weeks of tamsulosin monotherapy. Patients with longer lasting symptoms and storage symptoms with small prostate volume may require the anticholinergic add-on.

Persistence with solifenacin add-on therapy in men with benign prostate obstruction and residual symptoms of overactive bladder after tamsulosin monotherapy

AIMS

In spite of the reported efficacy and safety of antimuscarinics in men with OAB (overactive bladder) and BPO (benign prostatic obstruction), many patients do not persist with the treatment. We aimed to evaluate persistence and the reasons for the discontinuation of solifenacin add-on therapy in men with residual symptoms of OAB after tamsulosin monotherapy for BPO in a real clinical environment.

METHODS

Men aged ≥ 45 years with IPSS ≥ 12 and symptoms of OAB (OAB-V8 ≥ 8, micturition ≥ 8/24 h, urgency ≥ 2/24 h) were prescribed tamsulosin 0.2 mg. After 4 weeks, men who had residual symptoms of OAB (OAB-V8 ≥ 8, micturition ≥ 8/24 h, urgency ≥ 1/24 h) and reported that they were 'dissatisfied' or 'a little satisfied' with the therapy were enrolled and prescribed solifenacin 5 mg in combination with tamsulosin. After 52 weeks, persistence and the reasons for the discontinuation of solifenacin were evaluated. Factors related to persistence were analysed.

RESULTS

Of the 305 men who had been treated with tamsulosin, 176 were prescribed solifenacin. After 52 weeks, 44 (25%) remained on solifenacin therapy. Of the 132 who discontinued solifenacin, 85 were evaluated on the reason for discontinuation. The three most common reasons for discontinuation were adverse events (AEs) (35%), lack of efficacy (33%), and improvement in symptoms (16%). The aggravation of voiding symptoms was the most common AE leading to discontinuation. Retention was observed in 11 men. None of the demographical or clinical characteristics were significantly related to persistence.

CONCLUSIONS

Only 25% men with OAB and BPO remained on antimuscarinic add-on therapy after 1 year, mostly because of AEs and lack of efficacy. Realistic data should be added to what is already known about antimuscarinic treatment in men by including patients who were excluded or who dropped out of well-designed clinical trials.

The clinical outcome of end-stage renal disease patients who return to peritoneal dialysis after renal allograft failure

BACKGROUND

With the increased numbers of kidney transplantations, more patients return to dialysis after graft loss (DAGL). The aim of this study was to investigate the safety and efficacy of peritoneal dialysis (PD) after graft loss compared with transplant-naive PD patients (TN-PD).

METHOD

This study was conducted on 715 patients who started PD between 1988 and 2009, including 47 who started PD after allograft loss (DAGL-PD) and 668 in the (TN-PD) group.

RESULT

The mean ages were 40.8 ± 10.7 in DAGL-PD group and 51.03 ± 14.20 in TN-PD group (P < .01). The most common cause of end-stage renal disease in DAGL was primary glomerulonephritis (76.6%), but it was diabetes mellitus (38.9%) in the TN-PD group (P < .05). Patient survival rates at 1, 5, and 10 years were not different: 100%, 86%, and 57% versus 91%, 70%, and 62%, respectively. PD survival rate at 1, 5, and 10 years did not show significant differences: 98%, 95%, and 88% versus 95%, 80%, and 66%, respectively. The most common causes of death in both groups were infection (DAGL, 26.7%; TN-PD, 24.5%) followed by cardiovascular disease (DAGL, 20.0%; TN-PD, 19.6%); the distribution of causes did not differ significantly (P > .05).

CONCLUSION

The clinical outcomes of PD in DAGL group were comparable with those of TN-PD patients. Therefore, PD could be considered as a dialysis modality for patients who experience allograft failure.

Comparison of clinical outcomes in hepatitis B virus-positive kidney transplant recipients with or without pretransplantation antiviral therapy

BACKGROUND

Antiviral agents have improved the outcomes of hepatitis B virus (HBV)-positive kidney transplant recipients (KTRs). Preemptive therapy has been the main approach to forestall HBV reactivation. We sought to compare prophylactic and preemptive approaches.

METHODS

We divided the 69 HBV-positive KTRs into treatment and historical control groups, according to the time of starting pretransplantation antiviral therapy. The treatment group was further divided into prophylactic and preemptive therapy groups.

RESULTS

The treatment group showed a significant improvement in 10-year graft (82% vs 34%) and patient (91% vs 57%) survivals. Among the historical control group, the main causes of graft failure were patient deaths (68%), which were mostly caused by liver diseases. In contrast, there was no liver-related death in the treatment group. In addition, there was no difference in graft or patient survival between the prophylactic and preemptive groups, but the incidence of HBV reactivation was lower in the prophylactic group. Antiviral therapy was an independent factor for the improved patient survival (P = .005).

CONCLUSIONS

Pretransplantation antiviral therapy is essential to improve clinical outcomes. Prophylactic may be better than preemptive antiviral therapy to decrease HBV reactivation.

Combined use of rituximab and plasmapheresis pre-transplant increases post-transplant infections in renal transplant recipients with basiliximab induction therapy

INTRODUCTION

We investigated the effect of combined use of rituximab (RTX) and plasmapheresis (PP) pre-transplant on post-transplant infection.

METHODS

A total of 196 patients undergoing living-donor kidney transplantation at Seoul St. Mary's Hospital, all of whom underwent basiliximab induction therapy, were included in the study. They were divided into 3 groups: RTX/PP/intravenous immune globulin (IVIG) (the RPI group; n = 53), RTX monotherapy (the RTX group; n = 14), and control (the CONT group; n = 129). We compared the post-transplant infections in the 3 groups.

RESULTS

The overall prevalence of infection was significantly higher, and the infection-free survival rate was lower, in the RPI group compared with the RTX or CONT groups (P < 0.05). A trend toward more severe bacterial infections was seen in the RPI group compared with the other groups, and fungal infections developed only in the RPI group. After anti-rejection therapy, a significantly higher rate of infection developed in the RPI group than in the other groups (P < 0.05). In addition, the RPI group was an independent risk factor for the development of infection.

CONCLUSION

Our results show that in the setting of basiliximab induction, the use of combined RTX and PP therapy pre-transplant significantly increases the risk for post-transplant infection.

Highly efficient secretion of heterologous proteins from Saccharomyces cerevisiae using inulinase signal peptides

The INU genes of Kluyveromyces marxianus encode inulinases which are readily secreted from Saccharomyces cerevisiae into the culture medium. To evaluate the utility of the INU signal peptides for the secretion of heterologous proteins from S. cerevisiae, a variety of expression and secretion vectors were constructed with GAL10 promoter and GAL7 terminator. The coding sequence for human lipocortin-1 (LC1) was inserted in-frame with the INU signal sequences, and then the secretion efficiency and localization of LC1 were investigated in more detail and compared with those when being expressed by the vector with the MFalpha1 leader peptide. The vector systems with INU signal peptides secreted ca. 95% of the total LC1 expressed into the extracellular medium, while the MFalpha1 leader peptide-containing vector resulted in very low secretion efficiency below 10%. In addition, recombinant human interleukin-2 (IL-2) was expressed and secreted with the vector systems with INU signal peptide, and a majority fraction of the human IL-2 expressed was found to be secreted into the extracellular medium as observed in LC1 expression. (c) 1995 John Wiley & Sons, Inc.

Clinical usefulness of 3-dimensional computerized tomographic renal angiography to detect transplant renal artery stenosis

OBJECTIVE

The aim of this study was to evaluate whether 3-dimensional computerized tomographic angiography (3D-CTA) is useful to detect transplant renal artery stenosis (TRAS).

METHODS

Fourteen patients with clinically suspected TRAS underwent color Doppler ultrasonography (CDU) and 3D-CTA before renal angiography. We compared 3D-CTA and CDU for accuracy based on the results of renal angiography. The safety of 3D-CTA was investigated by measuring the estimated glomerular filtration rate (eGFR) before and after the 3D-CTA examination.

RESULTS

The 10 men and 4 women who participated in this study showed a mean eGFR of 75 mL/min/1.73 m(2) (range 60-94). Of these, 9 patients were diagnosed with TRAS. 3D-CTA detected stenoses in all 9 patients, but CDU failed to detect it in 3, including, 2 with end-to-side arterial anastomoses, which may be more challenging to detect compared with end-to-end anastomoses. The stenotic area in 3D-CTA was similar to that detected by renal angiography (70 ± 12 vs 68 ± 11). The eGFR did not differ significantly before versus after the 3D-CTA examination; 72 ± 13 vs 69 ± 14 mL/min/1.73 m(2).

CONCLUSIONS

3D-CTA was an effective safe method to detect renal artery stenosis among transplant recipients with an eGFR >60 mL/min/1.73 m(2).

Comparative rapid onset of efficacy between doxazosin gastrointestinal therapeutic system and tamsulosin in patients with lower urinary tract symptoms from benign prostatic hyperplasia: a multicentre, prospective, randomised study

AIMS

To compare the rapidity of improvement in lower urinary tract symptoms (LUTS) for the doxazosin gastrointestinal therapeutic system (GITS) and tamsulosin in benign prostatic hyperplasia (BPH) patients.

METHODS

A total of 207 patients were randomised to one of two groups for a 12-week daily treatment with doxazosin-GITS 4 mg or tamsulosin 0.2 mg. The primary end-point was to compare the early onsets of efficacy between the two drugs. This was assessed by analysing the changes from baseline in the total International Prostate Symptom Score (IPSS) in the early period of treatment. Secondary aims were to compare improvements in obstructive/irritative subscore and quality of life (QoL) score between the two groups, and to evaluate the adverse events (AEs) with the drugs.

RESULTS

After 12 weeks of treatment, both groups showed significant improvements in IPSS scores (total, obstructive and irritative subscores, QoL score) from baseline (p < 0.0001). However, the doxazosin-GITS group showed significantly greater improvements in total IPSS and obstructive subscore than the tamsulosin group in the early period (p < 0.05). Improvements in irritative subscore (within 4 weeks) and QoL score (during 12 weeks) were not significantly different between the groups. The incidences of AEs were similar between the groups.

CONCLUSION

In this study, doxazosin-GITS showed significantly more rapid onset of efficacy and similar AEs compared with tamsulosin in BPH patients with LUTS. We believe this will probably improve patient compliance. Future studies with a larger number of patients and a longer follow-up period will be required to confirm this.

Long-term outcome of tamsulosin for patients with lower urinary tract symptoms according to the treatment response defined by lower urinary tract symptom outcomes score

IMS: To evaluate long-term outcome of tamsuolsin 0.2 mg for benign prostatic hyperplasia (BPH) patients using a new subjective assessment of patient-reported outcomes and the lower urinary tract symptoms (LUTS) outcome score (LOS) over a 48-week period.

METHODS

This study investigated the long-term outcomes of either well-responded or poorly responded patient group as defined by LOS at the period of 12 weeks after BPH treatment. Outcome parameters used in this study were the most bothersome symptoms, BPH K1-short form as well as International Prostate Symptom Score (IPSS), maximum flow rate (Qmax) and postvoiding residual urine volume at 24-, 36- and 48-week follow-up.

RESULTS

Of the 414 patients recruited initially, 310 (75.2%) were defined as the responders and 39 (9.5%) as the non-responders to the treatment at 12 weeks, which was stratified by LOS. In this long-term study, the differences in improvement rates of clinical parameters between responder and non-responder groups at 12 weeks of treatment were maintained over the period of 48 weeks. Among the responder patients, most (75.6%) chose continuous administrations of tamsulosin. Improvements in clinical parameters were maintained in this subgroup. It is noteworthy that the improvements in clinical parameters of the non-responder group were dismal despite switching to the other treatment modalities.

CONCLUSIONS

Long-term tamsulosin 0.2 mg for BPH patients is an effective treatment, both subjectively and objectively. Considering its integrative nature, LOS seemed to be one of the useful tools to predict the outcome after the management of LUTS.

Effects of α-blocker 'add on' treatment on blood pressure in symptomatic BPH with or without concomitant hypertension

We investigated the effects of ‘add on' treatment of α-blocker (AB) on blood pressure (BP) and the safety of ABs in men with symptomatic BPH with or without hypertension. We retrospectively reviewed 2,924 BPH outpatients who took ABs at our institution between 2005 and 2009. BPH symptom severity, prostate volume and BP were determined for 953 patients with their baseline data. BP level and International Prostate Symptom Score were measured within 2 months after AB treatment. Patients were assigned to four groups: group 1 had 272 normotensive patients on concomitant hypertensive medication; group 2 had 293 normotensive patients not on the medication; group 3 had 216 hypertensive patients on concomitant medication; and group 4 had 172 hypertensive patients not on the medication. The addition of AB lowered the mean systolic BP by 16.6 mm Hg for group 3 and by 8.6 mm Hg for group 4, and diastolic BP by 18.0 mm Hg for group 3 (P&lt;0.05). However, normotensive groups on entry, irrespective of antihypertensive medication, showed no significant BP changes from baseline after AB medication. In the hypertensive groups on entry, the doxazosin gastrointestinal therapeutic system (GITS) resulted in significant reductions in systolic BP from 142.2 to 134.9 mm Hg and in diastolic BP from 97.6 to 84.6 mm Hg. When analyzed by AB regimen, the incidence of BP-related adverse events was comparable. AB therapy for BPH can have an appropriate and beneficial effect on BP, especially in baseline hypertensive patients. Doxazosin GITS treatment resulted in optimal management of BP within the normal range, especially in pharmacologically or physiologically hypertensive patients.

An open, non-comparative, multicentre study on the impact of alfuzosin on sexual function using the Male Sexual Health Questionnaire in patients with benign prostate hyperplasia

OBJECTIVES

To determine the effect of alfuzosin on sexual function by using the Male Sexual Health Questionnaire (MSHQ) in men with lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH).

PATIENTS AND METHODS

In this multicentre, open-label and non-comparative study, a total of 135 sexually active patients with LUTS were enrolled in Korea to receive alfuzosin 10 mg once daily for 12 weeks. International Prostate Symptom Score (IPSS) and a 25-item MSHQ exploring erection ejaculation and satisfaction with sex life were evaluated at baseline after 4 and 12 weeks of treatment.

RESULTS

Of 135 patients (age 58.8 years, duration of LUTS 2.6 years, mean values), 110 (81.5%) completed the study. The ejaculatory domain of the MSHQ significantly improved at the end-point in the intent-to-treat population (score difference of 2.24, p < or = 0.0001, n = 120). The domains of erection and sexual satisfaction improved at the end-point, but the score differences were not statistically significant. After the 12 weeks treatment, the total IPSS score significantly decreased from 17.9 to 12.1 (p < 0.0001), bother score decreased from 3.8 to 2.85 (p < 0.0001) and peak flow rate increased from 11.0 to 14.3 ml/s (p < 0.0001). A significant relationship between ejaculatory domains of MSHQ and IPSS was found. Four patients (2.9%) discontinued the trial for adverse event.

CONCLUSIONS

Based on the analysis of MSHQ scores before and after alfuzosin treatment, improvement was significant on ejaculatory function, in addition to improvement on LUTS and quality of life. MSHQ is a useful tool to evaluate the male sexual dysfunction.

The rate of Salmonella spp. infection in zoo animals at Seoul Grand Park, Korea

Salmonellosis is an important zoonotic disease that affects both people and animals. The incidence of reptile-associated salmonellosis has increased in Western countries due to the increasing popularity of reptiles as pets. In Korea, where reptiles are not popular as pets, many zoos offer programs in which people have contact with animals, including reptiles. So, we determined the rate of Salmonella spp. infection in animals by taking anal swabs from 294 animals at Seoul Grand Park. Salmonella spp. were isolated from 14 of 46 reptiles (30.4%), 1 of 15 birds (6.7%) and 2 of 233 mammals (0.9%). These findings indicate that vigilance is required for determining the presence of zoonotic pathogen infections in zoo animals and contamination of animal facilities to prevent human infection with zoonotic diseases from zoo facilities and animal exhibitions. In addition, prevention of human infection requires proper education about personal hygiene.

Current status of the anticoagulant hirudin: its biotechnological production and clinical practice

Hirudin is a potent thrombin inhibitor originally derived from the medicinal leech, Hirudo medicinalis. Owing to its high affinity and specificity for thrombin, hirudin has been intensively investigated for research and therapeutic purposes. The investigation of hirudin has contributed greatly to the understanding of the mode of action of thrombin and the clotting system. Hirudin and several hirudin analogues have also been demonstrated to have several advantages as a highly specific anticoagulant over the most widely used drug, heparin. Due to the great demand for hirudin in physicochemical and clinical studies, various recombinant systems have been developed, using bacteria, yeasts, and higher eukaryotes, to obtain the biologically active hirudin in significant quantities. After 10 years of clinical applications, two recombinant hirudins and a hirudin analogue have gained marketing approval from the United States Food and Drug Administration, for several applications. Clinical trials are currently ongoing for other treatments for thrombotic disease. As a consequence, it is conceivable that hirudin may expand its therapeutic utility over heparin in the near future.

Structure-activity relationship studies of isoquinolinone type anticancer agent

Substituted isoquinolin-1-ones (1) were synthesized to test their in vitro anticancer activity. 3-Biphenyl-N-methylisoquinolin-1-one (7) showed the most potent anticancer activity against five different human cancer cell lines.

Effects of docosahexaenoic acid and eicosapentaenoic acid on androgen-mediated cell growth and gene expression in LNCaP prostate cancer cells

There is some epidemiological support for a protective influence of omega-3 fatty acids against prostate cancer. We wanted to explore whether omega-3 polyunsaturated fatty acids such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) can affect androgen receptor function in prostate cancer cells. Our study showed that both DHA and EPA inhibit androgen-stimulated cell growth. Androgenic induction of prostate-specific antigen (PSA) protein was repressed by DHA and EPA in a dose-dependent manner. The mRNA levels of five androgen up-regulated genes, PSA, ornithine decarboxylase, NKX 3.1, immunophilin fkbp 51 and Drg-1, were decreased with DHA treatment in the presence of androgens. Transfection experiments using a DNA vector containing androgen-responsive elements demonstrated that both DHA and EPA could interfere with transactivation activities of the androgen receptor (AR). However, western blot analysis of AR protein showed that DHA and EPA treatments did not change AR expression levels. Interestingly, the proto-oncoprotein c-jun was increased by DHA treatment. A transient transfection found that forced expression of c-jun inhibited AR transactivation activity. Thus, this study found that the inhibitory effects of omega-3 polyunsaturated fatty acids on AR-mediated actions are due, at least in part, to an increase in c-jun protein.

Cationic domain 141-150 of apoE covalently linked to a class A amphipathic helix enhances atherogenic lipoprotein metabolism in vitro and in vivo

We previously showed 1 that a peptide, Ac-hE18A-NH(2), in which the arginine-rich heparin-binding domain of apolipoprotein E (apoE) [residues 141;-150] (LRKLRKRLLR), covalently linked to 18A (DWLKAFYDKVAEKLKEAF; a class A amphipathic helix with high lipid affinity), enhanced LDL uptake and clearance. Because VLDL and remnants contain more cholesterol per particle than LDL, enhanced hepatic clearance of VLDL could lead to an effective lowering of plasma cholesterol. Therefore, in the present article we compared the ability of this peptide to mediate/facilitate the uptake and degradation of LDL and VLDL in HepG2 cells. The peptide Ac-hE18A-NH(2), but not Ac-18A-NH(2), enhanced the uptake of LDL by HepG2 cells 5-fold and its degradation 2-fold. The association of the peptides with VLDL resulted in the displacement of native apoE; however, only Ac-hE18A-NH(2) but not Ac-18A-NH(2) caused markedly enhanced uptake (6-fold) and degradation (3-fold) of VLDL. Ac-hE18A-NH(2) also enhanced the uptake (15-fold) and degradation (2-fold) of trypsinized VLDL Sf 100;-400 (containing no immuno-detectable apoE), indicating that the peptide restored the cellular interaction of VLDL in the absence of its essential native ligand (apoE). Pretreatment of HepG2s with heparinase and heparitinase abrogated all peptide-mediated enhanced cellular activity, implicating a role for cell-surface heparan sulfate proteoglycans (HSPG). Intravenous administration of Ac-hE18A-NH(2) into apoE gene knockout mice reduced plasma cholesterol by 88% at 6 h and 30% at 24 h after injection. We conclude that this dual-domain peptide associates with LDL and VLDL and results in rapid hepatic uptake via a HSPG-facilitated pathway.

Refolding and purification of yeast carboxypeptidase Y expressed as inclusion bodies in Escherichia coli

The genes encoding carboxypeptidase Y (CPY) and CPY propeptide (CPYPR) from Saccharomyces cerevisiae were cloned and expressed in Escherichia coli. Six consecutive histidine residues were fused to the C-terminus of the CPYPR for facilitated purification. High-level expression of CPY and CPYPR-His(6) was achieved but most of the expressed proteins were present in the form of inclusion bodies in the bacterial cytoplasm. The CPY and CPYPR-His(6) produced as inclusion bodies were separated from the cells and solubilized in 6 and 3 M guanidinium chloride, respectively. The denatured CPYPR-His(6) was refolded by dilution 1:30 into the renaturation buffer (50 mM Tris-HCl containing 0.5 M NaCl and 3 mM EDTA, pH 8.0), and the refolded CPYPR-His(6) was further purified to 90% purity by single-step immobilized metal ion affinity chromatography. The denatured CPY was refolded by dilution 1:60 into the renaturation buffer containing CPYPR-His(6) at various concentrations. Increasing the molar ratio of CPYPR-His(6) to CPY resulted in an increase in the CPY refolding yield, indicating that the CPYPR-His(6) plays a chaperone-like role in in vitro folding of CPY. The refolded CPY was purified to 92% purity by single-step p-aminobenzylsuccinic acid affinity chromatography. When refolding was carried out in the presence of 10 molar eq CPYPR-His(6), the specific activity, N-(2-furanacryloyl)-l-phenylalanyl-l-phenylalanine hydrolysis activity per milligram of protein, of purified recombinant CPY was found to be about 63% of that of native S. cerevisiae CPY.

Inflammatory pseudotumor of urinary bladder

A previously healthy 44-year-old male was admitted with the chief complaint of intermittent gross hematuria. On initial ultrasonographic and CT examination, a grossly protruding intravesical tumor was noted and, under the impression of a malignant bladder tumor, transurethral resection was performed. The histological findings were spindle cells with elongated cytoplasm with rare mitotic figures distributed in myxoid stroma, consistent with diagnosis of inflammatory pseudotumor of the bladder. The benign nature of this tumor warrants conservative surgical management, usually consisting of transurethral resection or partial cystectomy. No reports of metastasis have been reported following complete excision. Therefore, any suspicion and recognition of this entity is imperative to avoid performing an irreversible radical procedure.

Refolding and purification of Zymomonas mobilis levansucrase produced as inclusion bodies in fed-batch culture of recombinant Escherichia coli

Zymomonas mobilis levansucrase was overproduced by the fed-batch culture of recombinant Escherichia coli harboring a novel expression system that is constitutively expressed by the promoter from the Rahnella aquatilis levansucrase gene. Most of the levansucrase was produced as inclusion bodies in the bacterial cytoplasm, accounting for approximately 20% of the total cellular protein. Refolding after complete denaturation by high concentrations of urea or guanidine hydrochloride was not successful, resulting in large amounts of insoluble aggregates. During the development of the refolding method, it was found that direct solubilization of the inclusion bodies with Triton X-100 reactivated the enzyme, with a considerable refolding efficiency. About 65% of inclusion body levansucrase was refolded into active levansucrase in the renaturation buffer containing 4% (v/v) Triton X-100. The in vitro refolded enzyme was purified to 95% purity by single-step DEAE-Sepharose ion exchange chromatography. Triton X-100 was removed by this ion exchange chromatography.

Comparison of single and multiple sessions of percutaneous sclerotherapy for simple renal cyst

OBJECTIVE

To compare the results of single and repeated percutaneous sclerotherapy in patients with simple renal cysts.

PATIENTS AND METHODS

Eighty-two patients with simple renal cysts underwent needle aspiration andsclerotherapy under ultrasonographic guidance. Forty-two patients (group 1) underwent one session of sclerotherapy with 99% ethanol immediately after aspiration and 40 patients (group 2) underwent sclerotherapy at least twice. The patients were followed up using ultrasonography at 3-month intervals. The complete disappearance or a reduction of more than half in the diameter of the renal cyst was considered a successful treatment.

RESULTS

The mean diameter of the renal cysts was not significantly different in group 1 (6.12 cm) and 2 (6.75 cm). There was complete or partial regression in eight (19%) and 16 (38%) in group 1, and in 29 (73%) and nine (23%) in group 2, respectively. The overall success rate was significantly better in group 2 (95%) than in group 1 (57%; P < 0.001).

CONCLUSIONS

These results suggest that multiple sclerotherapy is better than a single injection of sclerosant for reducing the recurrence of simple renal cysts.

Lipolytic remnants of human VLDL produced in vitro. Effect of HDL levels in the lipolysis mixtures on the apoCs to apoE ratio and metabolic properties of VLDL core remnants

To determine the role of high-density lipoprotein (HDL) as an acceptor of lipolytic surface remnants of very low density lipoprotein (VLDL) in the metabolism of VLDL core remnants, we examined the effect of HDL levels in the VLDL lipolysis mixture on 1) the morphology and the apoCs to E ratio in VLDL core remnants and 2) the metabolic properties of VLDL core remnants in human hepatoma cell line HepG2 and human hepatocytes in the primary culture. Normolipidemic VLDL was lipolyzed in vitro by purified bovine milk lipoprotein lipase (LpL) in a lipolysis mixture containing a physiologic level of VLDL and albumin (30 mg VLDL-cholesterol (CH)/dl and 6% albumin) in the absence and presence of either a low HDL level (VLDL-CH:HDL-CH = 3:1) or a high HDL level (VLDL-CH:HDL-CH = 1:4). Lipolysis of VLDL in either the absence or presence of HDL resulted in the hydrolysis of >85% of VLDL-triglycerides (TG) and the conversion of VLDL into smaller and denser particles. In the absence of HDL, heterogeneous spherical particles with numerous surface vesicular materials were produced. In the presence of low or high HDL, spherical particles containing some or no detectable vesicular surface components were produced. The apoCs to apoE ratios, as determined by densitometric scanning of the SDS polyacrylamide gradient gel, were 2.89 in control VLDL and 2.27, 0.91, and 0.22 in VLDL core remnants produced in the absence and in the presence of low and high HDL levels, respectively. In vitro lipolysis of VLDL markedly increased binding to HepG2 cells at 4 degrees C and internalization and degradation by human hepatocytes in primary culture at 37 degrees C. However, the HDL-mediated decrease in the apoCs to apoE ratio had a minimal effect on binding, internalization, and degradation of VLDL core remnants by HepG2 cells and human hepatocytes in primary culture. In order to determine whether HepG2 bound VLDL and VLDL core remnants are deficient in apoCs, (125)I-labeled VLDL and VLDL core remnants were added to HepG2 culture medium at 4 degrees C. The bound particles were released by heparin, and the levels of (125)I-labeled apoCs and apoE, relative to apoB, in the released particles were examined. When compared with those initially added to culture medium, the VLDL and VLDL core remnants released from HepG2 cells had a markedly increased (113%) level of apoE and a reduced (30-39%), but not absent, level of apoCs. We conclude that apoCs, as a minimum structural and/or functional component of VLDL and VLDL core remnants, may not have an inhibitory effect on the binding of VLDL or VLDL core remnants to hepatic apoE receptors.

Protein kinase C independent activation of inducible nitric oxide synthase by tumor necrosis factor-alpha in TM4 Sertoli cells

To investigate the nitric oxide (NO) production and its signalling mechanism in TM4 Sertoli cells, the cells were treated with recombinant tumor necrosis factor-alpha (rTNF-alpha), recombinant interleukin-1 alpha (rIL-1alpha), or lipopolysaccharide (LPS), either alone or in combination with recombinant interferon-gamma (rIFN-gamma), and NO production was measured by using the Griess method. TM4 Sertoli cells produced a small amount of NO upon treatment with rIFN-gamma. The effect of rIFN-gamma was drastically increased by cotreatment with rTNF-alpha in a dose-dependent manner. However, combination of rIL-1alpha or LPS with rIFN-gamma did not synergize to activate cells. RIFN-gamma in combination with rTNF-alpha showed marked increase of the expression of iNOS protein. Protein kinase C inhibitors did not inhibit the production of NO induced by rIFN-gamma plus rTNF-alpha. These results suggest that the role of TNF-alpha is to provide TM4 Sertoli cells with the active cofactor for NO production and TNF-alpha-induced signaling for induction of NO synthesis is not dependent on protein kinase C activation.

The receptor binding domain of apolipoprotein E, linked to a model class A amphipathic helix, enhances internalization and degradation of LDL by fibroblasts

Human apolipoprotein E (apo E) consists of two distinct domains, the lipid-associating domain (residues 192-299) and the globular domain (residues 1-191) which contains the LDL receptor (LDLR) binding site (residues 129-169). To test the hypothesis that an arginine-rich apo E receptor binding domain (residues 141-150) is sufficient to enhance low-density lipoprotein (LDL) uptake and clearance when covalently linked to a class A amphipathic helix, a peptide in which the receptor binding domain of human apo E, LRKLRKRLLR (hApoE[141-150]), is linked to 18A, a well-characterized high-affinity lipid-associating peptide (DWLKAFYDKVAEKLKEAF), we synthesized the peptide hApoE[141-150]-18A (hE18A) and its end-protected analogue, Ac-hE18A-NH(2). The importance of positively charged residues and the role of the hydrophobic residues in the receptor binding domain were also studied using four analogues. Ac-LRRLRRRLLR-18A-NH(2) [Ac-hE(R)18A-NH(2)] and Ac-LRKMRKRLMR-18A-NH(2) (Ac-mE18A-NH(2)) contained an extended hydrophobic face, including the receptor binding region. Control peptides, Ac-LRLLRKLKRR-18A-NH(2) [Ac-hE(Sc)18A-NH(2)], had the amino acid residues of the apo E receptor binding domain scrambled to disrupt the extended hydrophobic face, and Ac-RRRRRRRRRR-18A-NH(2) (Ac-R(10)18A-NH(2)) had only positively charged Arg residues as the receptor binding domain. The effect of the dual-domain peptides on the uptake and degradation of human LDL by fibroblasts was determined in murine embryonic fibroblasts (MEF1). LDL internalization was enhanced 3-, 5-, and 7-fold by Ac-mE18A-NH(2), Ac-hE18A-NH(2), and Ac-hE(R)18A-NH(2), respectively, whereas the control peptides had no significant biological activity. All three active peptides increased the level of degradation of LDL by 100%. The LDL binding and internalization to MEF1 cells in the presence of these peptides was not saturable over the LDL concentration range that was studied (1-10 microgram/mL). Furthermore, a similar enhancement of LDL internalization was observed independent of the presence of the LDL receptor-related protein (LRP), LDLR, or both. Pretreatment of cells with heparinase and heparitinase abolished more than 80% of the enhanced peptide-mediated LDL uptake and degradation by cells. We conclude that the dual-domain peptides enhanced LDL uptake and degradation by fibroblasts via a heparan sulfate proteoglycan (HSPG)-mediated pathway.

Improvement of intact human lipocortin-I production in Saccharomyces cerevisiae by inhibiting proteolysis

Human lipocortin-I (hLC1), when was expressed as a secretory product in Saccharomyces cerevisiae, was cleaved to a significant extent by endoproteolytic processing, resulting in the accumulation of des1-26-hLC1 in the culture supernatant. This proteolytic cleavage was inhibited significantly by the addition of high concentrations of l-arginine and l-lysine, with a resultant marked improvement in the yield of intact hLC1. When the hLC1 was expressed in S. cerevisiae mutants deficient in one or two of the following endoproteases, Kex2p, Mkc7p and Yps1p (Yap3p), the mutants exhibited no reduction in the extent of hLC1 proteolysis, indicating that these endoproteases are not involved in the proteolytic cleavage of hLC1.

Use of carboxypeptidase Y propeptide as a fusion partner for expression of small polypeptides in Escherichia coli

The carboxypeptidase Y (CPY) propeptide from Saccharomyces cerevisiae was developed as a fusion partner for the efficient expression of small polypeptides in Escherichia coli. Six consecutive histidine residues (6xHis) were fused to the N-terminus of the CPY propeptide for the facilitated purification of fusion proteins using immobilized metal ion affinity chromatography. In addition, a methionine or the pentapeptide (Asp)(4)-Lys linker was inserted at the junction between the CPY propeptide and the target polypeptide to release the target polypeptide by digestion with cyanogen bromide or enterokinase. Therapeutically valuable peptide hormones, such as salmon calcitonin precursor (sCAL-Gly), a fragment of human parathyroid hormone (hPTH(1-34)), and human glucagon were successfully expressed in E. coli as fusion polypeptides with the fusion partner. SDS-PAGE analyses showed that the majority of the expressed fusion sCAL-Gly and fusion hPTH(1-34) were present in the form of inclusion bodies, whereas about 66% of the expressed human glucagon was in a soluble form. Almost complete cleavage of the fusion polypeptides was obtained by digestion with enterokinase. Reverse-phase HPLC analyses showed that the target polypeptides released from the fusion proteins were identical to their native forms.

Synthesis of sesquiterpene derivatives as potential antitumor agents; elemane derivatives

Derivatives of elema-1,3-diene were synthesized in several steps as polar analogs of beta-elemene, antitumor agent under clinical phase. The lactone ring of compound 1 was opened by LiAlH4 to give diol 2 which was selectively protected by TBDPSCl. After acetylation of the secondary alcohol, the acetylated product was ozonolyzed and reduced to give elemane derivative 4 which was converted to diolefin 8 via selenides subsequent deprotection by tetrabutylammonium fluoride gave two compounds 9, 10.

A survey of helminthic infections in the residents of rural areas near Ulaanbaatar, Mongolia

A total of 738 samples was collected to survey the helminthic infections of residents in two rural areas near Ulaanbaatar, Mongolia for 2 weeks from July 23 to August 2, 1998. Among 391 scotch-taped slides of anal swabs of children and of young teenagers. Enterobius vermicularis eggs were detected in 138 cases (35.3%). With the fecal samples of 206 Kato-Katz thick smear slides from adults, the eggs of E. vermicularis were observed in 9 cases and Taenia sp. in one case, respectively. And by ELISA on 141 blood samples absorbed to blood sampling paper, 12 cases (8.5%) were found to be positive against the hydatid cyst antigen. Enterobiasis and hydatidosis are two major endemic diseases which are related closely to the life style of Mongolian.

Novel angiotensin-I-converting enzyme inhibitory peptides derived from recombinant human alpha s1-casein expressed in Escherichia coli

Recombinant human alpha s1-casein expressed in Escherichia coli was purified and digested with trypsin in an attempt to find peptides with angiotensin-I-converting enzyme (ACE) inhibitory activity. Three novel ACE inhibitory peptides, A-II, B-II and C, were isolated and their amino acid sequences identified as Tyr-Pro-Glu-Arg (residues 8-11), Tyr-Tyr-Pro-Gln-Ile-Met-Gln-Tyr (residues 136-143) and Asn-Asn-Val-Met-Leu-Gln-Trp (residues 164-170) respectively. ACE inhibitory activities were measured for the corresponding synthetic peptides, and the ACE IC50 (the amount of peptide causing 50% inhibition of ACE activity) values of A-II, B-II and C estimated to be 132.5, 24.8 and 41.0 mumol/l respectively. Peptides A-II and C were resistant to further digestion by pepsin, whereas peptide B-II was hydrolysed. All three peptides were resistant to digestion by chymotrypsin. These ACE inhibitory peptides may prove useful for oral administration in the treatment of hypertension.

A novel synthesis of benzo[c]phenanthridine skeleton and biological evaluation of isoquinoline derivatives

Benzo[c]phenanthridine skeleton was synthesized from easily available starting N-methyl-o-toluamide 2 and o-methylbenzonitrile 5 in 7 steps. Radical cyclization of styrene 10 afforded 6,11-dimethyl-6,11-dihydro-5H-indeno[1,2-c]isoquinolin-5-one 13. Most 3-arylisoquinolines have displayed strong activities against human tumor cell lines. Especially, indenoisoquinolinone 13 exhibited excellent cytotoxicity (IC50 = 0.002 microgram/ml; HCT 15).

Studies on the synthesis and in vitro antitumor activity of the isoquinolone derivatives

3-Arylisoquinolin-1(2H)-ones (2) are possible bioisosteres of the 5-[4'-(piperidinomethyl)phenyl]-2,3-dihydroimidazo[2,1-a]iso quinoline (1) which is in clinical evaluation for the treatment of cancer. Structure-activity relationship studies of 3-arylisoquinolin-1(2H)-ones (2) led to the synthesis of 3-arylquinolin-2(1H)-ones (3). A number of 3-phenyl substituted quinolin-2(1H)-ones were synthesized and tested for their in vitro antitumor activity against four different human tumor cell lines and 3-phenyl-N-benzyl-3,4-dihydroquinolin-2(1H)-one (12) showed the most potent activity.

The loss of expression of transforming growth factor-beta receptors correlates with the histopathologic tumor grade in bladder transitional cell carcinoma patients

Transforming growth factor-beta (TGF-beta), a pleiotropic growth factor, is a potent inhibitor of cellular proliferation in cells of epithelial origin. Recently, it has been suggested that a loss of sensitivity to TGF-beta through a loss of expression of TGF-beta receptors T beta R-I and T beta R-II--is associated with tumor initiation and progression. Therefore, to investigate the relationship between TGF-beta receptors expression and carcinogenesis of bladder TCC, this study examined the expression of T beta R-I and T beta R-II in 46 bladder TCC patients using immunohistochemistry. Since histopathological grade is a widely accepted marker of prognosis, the results were compared in relation to the three grades of bladder TCC. The results demonstrated that the loss of TGF-beta receptors expression is associated with increasing histopathological grades of bladder TCC. Specifically, both T beta R-I and T beta R-II were readily detected in all 10 normal bladder mucosa specimens. Likewise, all 6 specimens of grade I TCC samples expressed high levels of both TGF-beta receptors. However, among grade II TCC samples, T beta R-I and T beta R-II were detected in 78% and 89%, respectively: among grade III TCC samples, T beta R-I and T beta R-II were detected in 45% and 41%, respectively. These results suggested that loss of sensitivity to TGF-beta may play a role in the progression of TCC from low to high grade disease.

Synthesis and comparative molecular field analysis (CoMFA) of antitumor 3-arylisoquinoline derivatives

In this study a series of 3-arylisoquinoline derivatives were synthesized and cytotoxicity against human melanoma tumor cell evaluated, and a three dimensional quantitative structure-activity relationship was investigated using the comparative molecular field analysis (CoMFA). The results suggested that the electrostatic, steric and hydrophobic factors of 3-arylisoquinolines were strongly correlated with the antitumor activity. Considerable predictive ability (cross-validated r2 as high as 0.721) was obtained through CoMFA.

In vitro production of beta-very low density lipoproteins and small, dense low density lipoproteins in mildly hypertriglyceridemic plasma: role of activities of lecithin:cholester acyltransferase, cholesterylester transfer proteins and lipoprotein lipase

As a model for the formation of beta-very low density lipoproteins (VLDL) and small, dense LDL by the intraplasma metabolic activities in vivo, lipoproteins in fresh plasma were interacted in vitro with endogenous lecithin:cholesterol acyltransferase (LCAT) and cholesterylester transfer proteins (CETP) and subsequently with purified lipoprotein lipase (LpL). The LCAT and CETP reactions in a mildly hypertriglyceridemic (HTG) plasma at 37 degrees C for 18 h resulted in (1) esterification of about 45% plasma unesterified cholesterol (UC), (2) a marked increase in cholesterylester (CE) (+129%) and a decrease in triglyceride (TG) (-45%) in VLDL, and (3) a marked increase of TG (+ 341%) with a small net decrease of CE (-3.6%) in LDL, causing a significant alteration in the TG/CE of VLDL (from 8.0 to 1.9) and of LDL (from 0.20 to 0.93). The LDL in LCAT and CETP-reacted plasma is larger and more buoyant than that in control plasma. In vitro lipolysis of control and LCAT and CETP-reacted plasma by LpL, which hydrolyzed >90% of VLDL-TG and about 50-60% of LDL-TG, converted most of VLDL in control plasma (>85%) but less than half (40%) of VLDL in LCAT and CETP-reacted plasma into the IDL-LDL density fraction and transformed the large, buoyant LDL in the LCAT and CETP-reacted plasma into particles smaller and denser than those in the control plasma. The remnants that accumulated in the VLDL density region of the postlipolysis LCAT and CETP-reacted plasma contained apo B-100 and E but little or no detectable apo Cs and consisted of particles having pre-beta and beta-electrophoretic mobilities. The inhibition of LCAT during incubation of plasma, which lessened the extent of alteration in VLDL and LDL core lipids, increased the extent of lipolytic removal of VLDL from the VLDL density region but lowered the extent of alteration in the size and density of LDL. The LCAT, CETP and/or LpL-mediated alterations in the density of LDL in normolipidemic fasting plasma were less pronounced than that in mildly HTG plasma, but they became highly pronounced upon increase of its TG-rich lipoprotein level by the addition of preisolated VLDL or by the induction of postprandial lipemia. Although the effect of LCAT, CETP and LpL reactions in non-circulating plasma in vitro may be different from that in vivo, the above data suggests that the plasma TG-rich lipoprotein level and the extent of intraplasma LCAT, CETP, LpL and likely hepatic lipase (HL) reactions in vivo may play a role in determining the LDL phenotype.

Effect of the fat composition of a single meal on the composition and cytotoxic potencies of lipolytically-releasable free fatty acids in postprandial plasma

Ingestion of a meal increases plasma levels of triglyceride (TG)-rich lipoproteins through the secretion of intestine-derived chylomcirons and liver-derived very low density lipoproteins (VLDL). We have determined the effects of the fat composition of a single meal on the composition of TG in TG-rich lipoproteins (VLDL + chylomicrons) and circulating and lipolytically-releasable free fatty acids (FFA) in postprandial (PP) plasma and on the cytotoxic potencies of the lipolytically-released FFA to cultured arterial wall cells. PP lipemia was induced by feeding fasted normolipidemic human subjects with a meal rich in saturated fat (SF) and another meal rich in polyunsaturated fat (PUF), or vice versa; each meal provided 65% of energy as fat, and polyunsaturated to saturated fatty acid ratios (P/S) of the SF and PUF in the meals were 0.40 and 2.49, respectively. The mean P/S of TG in TG-rich lipoproteins (1.43) and circulating FFA (1.46) in 4 h PP plasma of PUF were significantly higher than those in PP plasma of SF (0.44 and 0.59, respectively) in fasting plasma (0.52 and 0.53, respectively). In vitro lipolysis of fasting and PP serum by purified bovine milk lipoprotein lipase (LpL) resulted in a marked (8.8-12.3-fold) increase in the serum FFA level. The P/S of serum FFA in postlipolysis fasting and PP serum were consistently higher than that of FFA or that of TG associated with TG-rich lipoproteins in prelipolysis fasting and PP serum, indicating that polyunsaturated TG in VLDL and/or chylomicrons is more susceptible than saturated TG to lipolysis. When postlipolysis serum was interacted with cultured endothelial cells and mouse peritoneal macrophages (MPM), the lipolytically-released FFA in PP serum of SF and PUF disrupted the barrier function of endothelial cells and were cytotoxic to cultured MPM; FFA in postlipolysis fasting serum was not cytotoxic. FFA in postlipolysis PP serum of PUF were consistently more potent than that in postlipolysis PP serum of SF. Further study showed that all long-chain monounsaturated FFA and polyunsaturated FFA, but not saturated FFA, incorporated into lipoproteins (LDL) were cytotoxic to cultured MPM. In conclusion, despite the generally well-accepted belief that SF is more atherogenic than PUF, the present study provides in vitro evidence that the lipolytic remnant products of TG-rich lipoproteins produced after a meal rich in PUF are more injurious to arterial wall cells than those produced after a meal rich in SF.

Potencies of lipoproteins in fasting and postprandial plasma to accept additional cholesterol molecules released from cell membranes

To investigate the role of various lipoproteins in plasma to promote cholesterol efflux from cell membranes, potencies of lipoproteins in normolipidemic fasting and postprandial (PP) plasmas to accept additional cholesterol molecules from cell membranes were determined. We used red blood cells (RBCs) and lipoproteins in fresh blood as donors and acceptors of cell membrane cholesterol, respectively. When fresh fasting plasma (n=24) containing active lecithin:cholesterol acyltransferase (LCAT) and cholesteryl ester transfer proteins (CETP) was incubated with a 3-fold excess of autologous RBCs at 37 degrees C for 18 hours, plasma cholesterol levels increased by 19.6% (38.5+/-14.2 mg/dL) owing to an exclusive increase in the CE level. Very low density lipoprotein (VLDL), low density lipoprotein (LDL), and high density lipoprotein (HDL) fractions retained 48.1%, 26.3%, and 25.6% of the net cholesterol mass increase in fasting plasma, resulting in 91%, 8%, and 21% increases in their cholesterol contents, respectively. The PP plasma was 1.3-fold more potent than fasting plasma in promoting cholesterol efflux from RBCs by associating excess cholesterol with chylomicrons, resulting in a 356% increase in the cholesterol content of chylomicrons. These increases in lipoprotein cholesterol content indicate that chylomicrons were about 3.9x, 44x, and 17x more potent than fasting VLDL, LDL, and HDL, respectively, in accepting additional cholesterol molecules released from RBCs. The capacity of PP plasma to promote cholesterol efflux from RBCs was significantly correlated with plasma cholesterol levels (r=0.60, P<0.005), triglycerides (r=0.68, P<0.001), chylomicrons (r=0.90, P<0.001), VLDL (r=0.65, P<0.001), and LDL (r=0.47, P<0.025) but not with the levels of HDL (r= -0.34, P<0.20). In fasting plasma containing a low level of VLDL and HDL, isolated chylomicrons supplemented to the plasma were approximately 9x more potent than HDL in boosting the capacity of plasma to promote cholesterol efflux from RBCs. This study indicates that chylomicrons in PP plasma are the most potent ultimate acceptors of cholesterol released from cell membranes and that a low HDL level is not a factor that limits the ability of PP plasma to promote cholesterol efflux from cell membranes. Our data obtained from an in-vitro system suggest that PP chylomicrons may play a major role in promoting reverse cholesterol transport in vivo, since the transfer of cholesterol from cell membranes to chylomicrons will lead to the rapid removal of this cholesterol by the liver. HDL in vivo may promote reverse cholesterol transport by enhancing the rapid removal of chylomicrons from the circulation, since the rate of clearance of chylomicrons is positively correlated with the HDL level in plasma.

Efficient production of intact human parathyroid hormone in a Saccharomyces cerevisiae mutant deficient in yeast aspartic protease 3 (YAP3)

When human parathyroid hormone (hPTH) is expressed as a secretory product in yeast, the main problem is the aberrant proteolytic cleavage that reduces the yield of intact protein. To overcome this problem, we developed an hPTH expression system using a host strain in which the YAP3 gene encoding yeast aspartic protease 3 (YAP3) was disrupted. After 48 h of culture, most of the hPTH secreted by the yap3 disruptant remained intact, whereas more than 90% of the hPTH secreted by the wild-type strain was cleaved. When the authentic hPTH was incubated in each of the culture supernatants of untransformed yap3 disruptant and wild-type strain, the proteolysis proceeded much more slowly in the culture supernatant of yap3 disruptant than in that of the wild type. The extent of hPTH proteolysis was also significantly reduced by the addition of pepstatin A, a specific aspartic protease inhibitor. The results suggest that YAP3 is involved in the internal cleavage of hPTH expressed in yeast. The correct processing of the intact hPTH secreted in the yap3 disruptant demonstrates that the yeast mutant lacking the YAP3 activity is a suitable host for the high-level expression of intact hPTH.