Cerebral blood flow in patients with peritoneal dialysis by an easy Z-score imaging system for brain perfusion single-photon emission tomography

Cognitive impairment has long been recognized as a complication of chronic kidney disease. However, there is little information available regarding regional cerebral blood flow (rCBF) in patients with peritoneal dialysis (PD). Therefore, we evaluated rCBF using brain single photon emission computed tomography (SPECT). We conducted a cross-sectional study in our hospital. Eighteen consecutive PD patients who could visit the hospital by themselves without any history of stroke were examined by Technetium-99 m-labeled ethylcrysteinate dimer brain SPECT. An easy Z-score imaging system (eZIS) was used to compare rCBF in PD patients with those in age-matched healthy controls. We also evaluated cognitive dysfunction with the mini-mental state examination (MMSE) questionnaire. Only one patient showed an MMSE score of 18 points, and the remaining 14 patients were considered as normal (MMSE ≥ 27), and three patients were considered to have mild cognitive impairment (24 ≤ MMSE ≤ 26). In all patients, rCBF in the posterior cingulated gyri, precunei, and parietal cortices was significantly decreased. The ratio of the reduction of rCBF in each region relative to that of rCBF across the whole brain correlated positively with the PD duration (r = 0.559; P < 0.05). The serum β2-microglobulin level was significantly higher in patients who had a higher ratio of rCBF reduction compared with those with lower ratios. In conclusion, all PD patients in the present study had decreased rCBF irrespective of MMSE scores.

Usefulness of intraoperative diagnosis of hepatic tumors located at the liver surface and hepatic segmental visualization using indocyanine green-photodynamic eye imaging

BACKGROUND

To improve the diagnostic accuracy for hepatic tumors on the liver surface, we investigated the usefulness of an indocyanine green-photodynamic eye (ICG-PDE) system by comparison with Sonazoid intraoperative ultrasonography (IOUS) in 117 patients. Hepatic segmentation by ICG-PDE was also evaluated.

METHODS

ICG was administered preoperatively for functional testing and images of the tumor were observed during hepatectomy using a PDE camera. ICG was injected into portal veins to determine hepatic segmentation.

RESULTS

Accurate diagnosis of liver tumors was achieved with ICG-PDE in 75% of patients, lower than with IOUS (94%). False-positive and false-negative diagnosis rates for ICG-PDE were 24% and 9%, respectively. New small HCCs were detected in 3 patients. The ICG fluorescent pattern in tumors was strong staining in 41%, weak staining in 13%, rim staining in 20% and no staining in 26%. Hepatocellular carcinoma predominantly showed strong staining (61%), while rim staining predominated in cholangiocellular carcinoma (60%) and liver metastasis (55%). Hepatic segmental staining was performed in 28 patients, proving successful in 89%.

CONCLUSION

ICG-PDE is a useful tool for detecting the precise tumor location at the liver surface, identifying new small tumors, and determining liver segmentation for liver resection.

Influence of losartan intake on the circadian rhythm of melatonin secretion in humans

It has been reported that losartan, an angiotensin II receptor blocker, alters the circadian rhythm of melatonin secretion and significantly reduces melatonin production. However, this finding has been confirmed at the animal experiment level only, and there are no reports of studies in humans. Therefore, we performed this study to confirm the reproducibility of the aforementioned findings of animal experiments in humans. Ten male subjects who were in good general health and free from any medical condition were recruited for this study. After a preliminary observation period of 7 days, the subjects received oral losartan treatment, 50 mg daily for 7 days. Blood samplings for measurement of the plasma melatonin concentrations were performed on day 7 of the preliminary observation period and day 7 of the losartan treatment period. The circadian rhythm of melatonin secretion after the 7-day treatment with losartan showed no significant difference from that recorded before the losartan administration. The significant decrease of the home blood pressure was observed on the afternoons. The blood samples showed significant decrease of the serum sodium and uric acid levels, along with a significant increase of the serum potassium level. The pharmacological actions of losartan at the ordinarily used clinical dose level were confirmed in humans, however, no significant inhibitory effect of the drug on melatonin secretion could be confirmed. These results are expected to be useful for guiding the proper use of angiotensin II receptor blockers.

Aliskiren, a direct renin inhibitor, improves vascular endothelial function in patients on hemodialysis independent of antihypertensive effect ∼ a pilot study∼

AIMS

Aliskiren inhibits the first step in the renin-angiotensin system (RAS) and recently has been shown to modulate vascular diseases via RAS-dependent and independent pathways. This study aimed to determine the effect of aliskiren-associated direct renin inhibition on endothelial function in patients on hemodialysis via flow-mediated dilatation (FMD) and platelet-derived microparticles (PDMP), as biomarkers of atherosclerosis.

METHODS

A 12-week prospective study was performed with 24 patients on hemodialysis who were administered 150 mg orally aliskiren once daily for 12 weeks.

RESULTS

No significant difference were observed between pre-dialysis, home, and weekly averaged blood pressure at baseline and at 12 weeks (151.5 ± 8.5/80.9 ± 12.9 mmHg vs 150.3 ± 15.3/78.9 ± 21.2 mmHg, 151.4 ± 9.7/82.3 ± 14.7 mmHg vs 151.2 ± 17.7/81.4 ± 10.6 mmHg, and 156.0 ± 18.3/81.9 ± 9.4 mmHg vs 152.5 ± 18.9/81.7 ± 12.3 mmHg, respectively). FMD significantly increased from 2.54% ± 1.45% at baseline to 3.11% ± 1.37% at 12 weeks (P = 0.0267), and PDMP significantly decreased from 13.9 ± 5.8 U/mL at baseline to 10.9 ± 4.5 U/mL at 12 weeks (P = 0.0002).

CONCLUSION

Aliskiren improved vascular endothelial function and platelet-endothelium activation in patients on hemodialysis independent of antihypertensive effect.

Lanthanum carbonate delays progression of coronary artery calcification compared with calcium-based phosphate binders in patients on hemodialysis: a pilot study

BACKGROUND AND OBJECTIVES

Coronary artery calcification (CAC) is associated with future cardiovascular events and/or death of patients on hemodialysis (HD). We investigated whether progression of CAC in patients on HD could be delayed by switching from a calcium (Ca)-based phosphate (Pi) binder to lanthanum carbonate.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

The CAC scores were evaluated at study enrollment and after 6 months in 52 patients on HD using calcium carbonate (CC) as a Pi binder. Patients were randomly divided into 2 groups assigned to receive either CC or lanthanum carbonate (LC), and the CAC scores were evaluated after a 6-month treatment period. Progression of CAC was assessed, as were serum levels of Ca, Pi, and intact parathyroid hormone (iPTH).

RESULTS

Forty-two patients completed the study (23 receiving CC and 19 receiving LC). In the 6 months prior to randomization, all patients were treated with CC. During this 6-month period, the CAC scores increased significantly in all 42 patients. Once randomized, there was significantly less progression in the group treated with LC than with CC. Changes in CAC scores from 6 to 12 months were significantly smaller in the LC group than the CC group (-288.9 ± 1176.4 vs 107.1 ± 559.6, P = .036), and percentage changes were also significantly different (-6.4% vs 41.2%, P = .024). Serum Ca, Pi, and iPTH levels were similar in both groups during the study period.

CONCLUSIONS

This pilot study suggested that LC delayed progression of CAC in patients on HD compared with CC.

Examination of factors that delay the elution of acetaminophen from over-the-counter drugs

The information on the stability of medications is important to secure their quality. There is, however, little information about the stability of medications which assume to be kept by patients and customers. We previously showed that a delay in drug release occurs in some over-the-counter (OTC) drugs following storage in a high temperature, high humidity environment. In this study we prepared model tablet formulations containing an active ingredient and excipients to investigate the cause of this delayed release. The results reveal that delayed release occurs in preparations compounded with acetaminophen (AA) as the active ingredient and erythritol (ET) and crospovidone (CP) as excipients. In addition, ET deliquesces in a high humidity environment, then incorporates other particles during room temperature storage to form an aggregate. SEM observations and micropore distribution measurements conducted on OTC tablets that exhibit delayed release revealed that the number of intraparticle pores decreased after storage under high temperature, high humidity conditions. Thus, the delayed release by these pharmaceutical product formulations may be due to a change in the micropore structure both on the surface and within the particles, thereby decreasing the solvent infiltration pathways leading to the interior of the preparation.

Sarpogrelate hydrochloride, a selective 5-HT(2A) receptor antagonist, improves skin perfusion pressure of the lower extremities in hemodialysis patients with peripheral arterial disease

BACKGROUND

Peripheral arterial disease (PAD) frequently occurs in patients on hemodialysis (HD); however, little is known about the effectiveness of drugs. We compare the effects of sarpogrelate and cilostazol in HD patients with PAD.

METHODS

We conducted a prospective, randomized, open-label, and multicenter trial for 24 weeks in HD patients with PAD. Thirty-five patients were divided into two groups: sarpogrelate (n = 17) and cilostazol (n = 18). We analyzed changes in skin perfusion pressure (SPP), levels of oxidative stress biomarkers, and adverse events.

RESULTS

At 24 weeks, SPP was increased in both groups (sarpogrelate, 43 ± 17 to 55 ± 15 mmHg; cilostazol, 49 ± 21 to 66 ± 29 mmHg; p < 0.05), and no difference was observed between the groups. Plasma pentosidine levels decreased in both groups (sarpogrelate, 0.65 ± 0.24 to 0.48 ± 0.12 mg/mL; cilostazol, 0.58 ± 0.22 to 0.47 ± 0.17 mg/mL; p < 0.05), and there were no differences between the groups. Serum malondialdehyde-modified low-density lipoprotein (MDA-LDL) levels significantly increased only in cilostazol group (p < 0.05). There were no clinically significant safety concerns linked to the both drugs. Although blood pressure did not differ in both groups, heart rate increased only in cilostazol group from 77 ± 13 to 83 ± 16 beats per minute (p < 0.05).

CONCLUSION

Sarpogrelate improves SPP in HD patients with PAD without increasing heart rate and serum MDA-LDL levels. We demonstrated that sarpogrelate is an effective and safe drug for the treatment of HD patients with PAD.

Correlation of coronary artery calcification with pre-hemodialysis bicarbonate levels in patients on hemodialysis

Coronary artery calcification (CAC) leads to a significant increase in cardiovascular morbidity and mortality in hemodialysis (HD) patients. Metabolic acidosis, which is common in HD patients, promotes bone resorption in human and animals as a result of buffer function of bone, and calcium and phosphate elute from bone into blood stream. However, the effect of acidosis on CAC in HD patients has never been precisely investigated. This is a cross-sectional observational study performed in a single center. One hundred and seven prevalent HD patients (35 women and 72 men) underwent electron-beam computed tomography (EBCT) to evaluate CAC score (CACS), and then we evaluated associated factors of CACS with clinical and laboratory parameters including pre-HD pH and bicarbonate levels. Pre-HD pH and bicarbonate levels were 7.35 ± 0.04, and 17.6 ± 1.8 mmol/L, respectively. The pre-HD pH had no significant correlation to CACS (r = -0.025, P = 0.81). CACS was significantly negatively correlated with pre-HD bicarbonate levels (r = -0.329, P = 0.0009) and serum albumin levels (r = -0.298, P = 0.0467), while it was positively correlated with age (r = 0.319, P = 0.0008) and HD duration (r = 0.385, P = 0.0004). Serum levels of calcium, phosphorus, intact parathyroid hormone, and use of phosphorus binders were not related to CACS. Multivariate analysis indicated that plasma pre-HD bicarbonate level was independently associated with CACS. The present study showed that blood levels of pre-HD bicarbonate were significantly associated with CAC in HD patients. Further studies are needed to confirm these results and to determine whether correction of metabolic acidosis prevents the development of CAC, one of the features of accelerated atherosclerosis in HD patients.

Role of major histocompatibility complex class II in the development of autoimmune type 1 diabetes and thyroiditis in rats

Although the MHC class II 'u' haplotype is strongly associated with type 1 diabetes (T1D) in rats, the role of MHC class II in the development of tissue-specific autoimmune diseases including T1D and autoimmune thyroiditis remains unclear. To clarify this, we produced a congenic strain carrying MHC class II 'a' and 'u' haplotypes on the Komeda diabetes-prone (KDP) genetic background. The u/u homozygous animals developed T1D similar to the original KDP rat; a/u heterozygous animals did develop T1D but with delayed onset and low frequency. In contrast, none of the a/a homozygous animals developed T1D; about half of the animals with a/u heterozygous or a/a homozygous genotypes showed autoimmune thyroiditis. To investigate the role of genetic background in the development of thyroiditis, we also produced a congenic strain carrying Cblb mutation of the KDP rat on the PVG.R23 genetic background (MHC class II 'a' haplotype). The congenic rats with homozygous Cblb mutation showed autoimmune thyroiditis without T1D and slight to severe alopecia, a clinical symptom of hypothyroidism such as Hashimoto's thyroiditis. These data indicate that MHC class II is involved in the tissue-specific development of autoimmune diseases, including T1D and thyroiditis.