Palmitoylation couples insulin hypersecretion with ß cell failure in diabetes.

Hyperinsulinemia often precedes type 2 diabetes. Palmitoylation, implicated in exocytosis, is reversed by acyl-protein thioesterase 1 (APT1). APT1 biology was altered in pancreatic islets from humans with type 2 diabetes, and APT1 knockdown in nondiabetic islets caused insulin hypersecretion. APT1 knockout mice had islet autonomous increased glucose-stimulated insulin secretion that was associated with prolonged insulin granule fusion. Using palmitoylation proteomics, we identified Scamp1 as an APT1 substrate that localized to insulin secretory granules. Scamp1 knockdown caused insulin hypersecretion. Expression of a mutated Scamp1 incapable of being palmitoylated in APT1-deficient cells rescued insulin hypersecretion and nutrient-induced apoptosis. High-fat-fed islet-specific APT1-knockout mice and global APT1-deficient db/db mice showed increased ß cell failure. These findings suggest that APT1 is regulated in human islets and that APT1 deficiency causes insulin hypersecretion leading to ß cell failure, modeling the evolution of some forms of human type 2 diabetes.

Multidimensional analysis and therapeutic development using patient iPSC-derived disease models of Wolfram syndrome.

Wolfram syndrome is a rare genetic disorder largely caused by pathogenic variants in the WFS1 gene and manifested by diabetes mellitus, optic nerve atrophy, and progressive neurodegeneration. Recent genetic and clinical findings have revealed Wolfram syndrome as a spectrum disorder. Therefore, a genotype-phenotype correlation analysis is needed for diagnosis and therapeutic development. Here, we focus on the WFS1 c.1672C>T, p.R558C variant, which is highly prevalent in the Ashkenazi Jewish population. Clinical investigation indicated that patients carrying the homozygous WFS1 c.1672C>T, p.R558C variant showed mild forms of Wolfram syndrome phenotypes. Expression of WFS1 p.R558C was more stable compared with the other known recessive pathogenic variants associated with Wolfram syndrome. Human induced pluripotent stem cell-derived (iPSC-derived) islets (SC-islets) homozygous for WFS1 c.1672C>T variant recapitulated genotype-related Wolfram syndrome phenotypes. Enhancing residual WFS1 function through a combination treatment of chemical chaperones mitigated detrimental effects caused by the WFS1 c.1672C>T, p.R558C variant and increased insulin secretion in SC-islets. Thus, the WFS1 c.1672C>T, p.R558C variant causes a mild form of Wolfram syndrome phenotypes, which can be remitted with a combination treatment of chemical chaperones. We demonstrate that our patient iPSC-derived disease model provides a valuable platform for further genotype-phenotype analysis and therapeutic development for Wolfram syndrome.

Quality and Quantity-Cultured Human Mononuclear Cells Improve Human Fat Graft Vascularization and Survival in an In Vivo Murine Experimental Model.

BACKGROUND: Fat graft ischemia impedes us from having satisfying long-term results. The quality and quantity culture is a 1-week cell culture that increases the vasculogenic potential of peripheral blood mononuclear cells (PBMNC). This in vivo murine model investigates whether enrichment with quality and quantity-cultured human mononuclear cells (MNC-QQ) improves the vascularization in the human fat graft and whether this decreases the tissue loss. METHODS: Human adipose tissue, PBMNC, MNC-QQ, and stromal vascular fraction were prepared. First, PBMNC, MNC-QQ, and stromal vascular fraction were compared in vitro for vasculogenic potential by endothelial progenitor cell colony-forming and culture assays. Second, 0.25-g fat grafts were created with 1 × 106 PBMNC (n = 16), 1 × 106 MNC-QQ (n = 16), 1 × 106 stromal vascular fraction (n = 16), or phosphate-buffered saline as control (n = 16) before grafting in BALB/c nude mice. Grafts were analyzed for weight persistence, vessel formation by CD31 immunohistochemistry, and angiogenic markers by quantitative polymerase chain reaction. RESULTS: MNC-QQ develop more definitive endothelial progenitor cell colonies and more functional endothelial progenitor cells compared to PBMNC and stromal vascular fraction. Weight persistence after 7 weeks was significantly higher in grafts with MNC-QQ (89.8 ± 3.5 percent) or stromal vascular fraction (90.1 ± 4.2 percent) compared with control (70.4 ± 6.3 percent; p < 0.05). MNC-QQ-enriched grafts had the highest vessel density (96.6 ± 6.5 vessels/mm2; control, 70.4 ± 5.6 vessels/mm2; p < 0.05). MNC-QQ exerted a direct vasculogenic effect through vascular integration and a potential paracrine vascular endothelial growth factor-mediated effect. CONCLUSION: Quality and quantity-cultured human mononuclear cells containing endothelial progenitor cells stimulate fat graft vascularization and enhance graft survival in a rodent recipient.

The impact of ferritin fluctuations on stable hemoglobin levels in hemodialysis patients.

BACKGROUND: Hemoglobin (Hb) cycling in patients with renal anemia might be associated with a higher mortality rate. We investigated the association of factors relating serum ferritin and dose of erythropoiesis-stimulating agents (ESAs) with Hb levels. METHODS: We measured Hb and ferritin levels every month in 266 hemodialysis (HD) patients for 12 months. RESULTS: The standard deviation (SD) and residual SD (RSD) (liner regression of Hb or ferritin SD values) values of Hb were significantly correlated with ferritin SD or RSD values, respectively. The percentage achievement of target Hb in the target-ferritin group was significantly higher than in the high-amplitude fluctuation ferritin group. Ferritin SD and RSD values in patients with oral or no iron supplementation were significantly lower than those who received intravenous iron. CONCLUSION: Iron storage varies over a relatively wide range in HD patients, and this variation is closely associated with Hb cycling. The stability of iron storage and ESA dosage is important for maintaining stable Hb levels.

Effects of acetate-free citrate-containing dialysate on metabolic acidosis, anemia, and malnutrition in hemodialysis patients.

Previously, dialysate contained small amounts of acetate as an alkaline buffer. Recently, acetate-free dialysate (A[-]D) has been available. We evaluated the clinical effect of A(-)D over acetate-containing dialysate (A(+)D) on acid-base balance, anemia, and nutritional status in maintenance hemodialysis (MHD) patients. Twenty-nine patients on MHD were treated with A(+)D for 4 months (first A(+)D), switched to A(-)D for 4 months, and returned to A(+)D for the next 4-month period (second A(+)D). Metabolic acidosis: Serum bicarbonate (HCO3(-) ) levels did not change in patients with normal HCO3(-) levels (≥20 mEq/L) throughout the study. Meanwhile, in patients with initially low HCO3(-) levels, it was significantly increased during the A(-)D period only. Anemia: In patients with target hemoglobin (Hb) ≥10 g/dL, Hb levels were maintained during the study period, even if the dose of erythropoiesis-stimulating agents (ESAs) decreased. In patients with low Hb levels, it was significantly increased in the A(-)D period without increasing ESA or iron doses. Nutritional Condition: In patients with normal albumin levels (≥3.8 g/dL), albumin did not change throughout the study period. However, in patients with lower albumin levels, it was significantly increased during the A(-)D period. These improvements in metabolic acidosis, anemia, and nutrition in the A(-)D period completely dissipated during the second A(+)D period. Hemodialysis (HD) with A(-)D may improve a patient's clinical status with intractable metabolic acidosis, hyporesponsiveness to ESA, and malnutrition that were not normalized in HD with A(+)D.

A crossover study of the acrylonitrile-co-methallyl sulfonate and polysulfone membranes for elderly hemodialysis patients: the effect on hemodynamic, nutritional, and inflammatory conditions.

Many maintenance hemodialysis (MHD) patients have recently been treated with high flux (HF) dialysis membranes such as polysulfone (PSu) membranes. However, the appropriateness of HF for elderly MHD remains to be elucidated. In order to estimate hemodialysis (HD) efficiency, the hemodynamic condition during HD, and the nutritional status, 28 elderly MHD patients were treated with PSu for 3 months. After this, the patients were switched to acrylonitrile-co-methallyl sulfonate (AN69) membranes for the next 3 months and then returned to PSu for another 3 months. Reduction ratio of inflammatory cytokines (interleukin [IL]-6) by AN69 was significantly higher than the reduction ratio by PSu. After 3 months with AN69, the serum total protein, albumin, and cholesterol levels significantly increased, and after switching back to PSu, the levels returned to baseline. Furthermore, the frequency of saline used to treat episodes of hypotension during HD significantly decreased in the AN69 period. In elderly MHD patients, it was possible to achieve improvements in both malnutrition and chronic inflammatory conditions with AN69. This suggests that AN69 may be the preferred membrane for elderly MHD, because it stabilizes the hemodynamic condition and demonstrates a higher removal of inflammatory cytokines during HD.

Pathological role of aminolevulinate in uremic patients.

Previous reports have demonstrated that δ-aminolevulinate (ALA) can promote iron release from horse spleen ferritin under conditions of high serum ALA levels in uremia; therefore, we speculated that the accumulated ALA in uremic patients would stimulate iron release from ferritin, resulting in accelerated oxidative stress and uremic complications. We measured the plasma ALA of uremic patients and examined the ALA-induced iron release from human ferritin. The participants consisted of 30 hemodialysis patients and 14 healthy subjects. Plasma malondialdehyde was measured as a surrogate marker of lipid peroxidation. The plasma exchange effluent from two patients who had undergone plasma exchange (for the treatment of systemic lupus erythematosus and acute myeloblastic leukemia) was collected and treated to obtain the human ferritin-rich fraction. Iron release from ferritin was examined using bathophenanthroline sulfate. The influence of antioxidants and different pH levels on iron release were investigated. Plasma ALA and malondialdehyde concentration in the hemodialysis patient was significantly higher than that in healthy subjects. ALA was positively correlated with malondialdehyde. The abundance of iron release was dependent on the ALA concentration and incubation time. Iron release at the high pH of 7.6 was decreased compared with that at pH 7.4. Citrate increased iron release at pH 7.4, but citrate-stimulated iron release was totally abolished at pH 7.6. Our study suggests that ALA accumulation may have a role to play in certain complications in uremic patients, such as oxidative stress, by releasing iron from ferritin.

Hepcidin as well as TNF-α are significant predictors of arterial stiffness in patients on maintenance hemodialysis.

BACKGROUND: Dysregulated iron metabolism has been suspected to be linked to anemia of chronic disease and to cardiovascular disease (CVD). For the purpose of clarifying the factors affecting arterial stiffness, we evaluated the relationship between iron metabolism, brachial-ankle (ba)-pulse wave velocity (PWV) and several risk factors for CVD in maintenance hemodialysis (MHD) patients. METHODS: A total of 168 MHD patients were recruited, and the levels of iron parameters, hepcidin, CVD risk factors and ba-PWV were evaluated. The level of serum hepcidin-25 was specifically measured by liquid chromatography-tandem mass spectrometry. RESULTS: Serum levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and hepcidin were higher in MHD patients, which was consistent with results from our previous study. ba-PWV significantly correlated with age (P < 0.01, R = 0.34), total cholesterol (T-CHO; P = 0.02, R = 0.21), TNF-α (P < 0.01, R = 0.24) and hepcidin (P < 0.01, R = 0.25) but not with other iron parameters and CVD risk factors. According to multiple regression analysis, age (ß = 0.30), T-CHO (ß = 0.24) TNF-α (ß = 0.19) and hepcidin (ß = 0.23) were selected as the significant predictors of ba-PWV in MHD patients. CONCLUSION: Serum levels of both hepcidin and TNF-α are independently associated with arterial stiffness in MHD patients, suggesting that microinflammation and iron metabolism might affect the integrity of arterial walls.

A case of a maintenance hemodialysis patient in whom a change of sensitivity to acetate was suspected.

Sodium acetate, which is a buffering agent in dialysates, has a vasodilatation effect as well as effects for depression of myocardial contractility even in low dosages. Also, it is presumed to be one of the causes of hypotension during hemodialysis (HD). In recent years, acetate-free dialysates [A(-)D] have been developed. In this case, although it was possible to maintain a relatively stable hemodynamic condition during HD using 10 mEq/L of acetate-containing dialysate [A(+)D], after HD using A(-)D for 4 months and then switched back to A(+)D, the patient complained of several symptoms such as nausea, vomiting, and headache, and severe hypotension episodes increased during HD. Furthermore, stabilization of the hemodynamic condition was obtained after switching back to A(-)D. Moreover, the nutritional state and anemia were improved. Conventionally, it has been considered that cases referred to as acetate intolerance have various symptoms with increasing blood acetate levels; however, this case suggests the possibility that tolerance to acetate was acquired by using the A(+)D over time, and the tolerance dissipated after using the A(-)D for 4 months. The number of cases involving broadly defined acetate intolerance as in this case was higher than expected. These findings suggest that using A(-)D for such cases, it may therefore be possible to maintain stable hemodynamic conditions during HD and improve the nutritional state and anemia.

[Myoclonus following spinal and epidural anesthesia--a case report].

We report a case of spinal myoclonus following cesarean section. The patient was a 34-year-old woman without history of neurologic disorders. In the operating room, after placement of an epidural catheter at T12-L1, bupivacaine 2.4 ml was administered intrathecally via a 25 G needle at L2-3. Epidural administration of ropivacaine (0.13%, 4 ml x hr(-1)) was started 72 min after spinal anesthesia. The intra- and postoperative courses were otherwise uneventful. The patient complained of involuntary jerky movements of her lower legs 195 min after the start of the spinal anesthesia. The sensory level was T12 and she could move her legs on command but could not stop her involuntary movements. The myoclonic movements ceased 150 min later without medication and did not reappear, despite restarting the epidural anesthesia with ropivacaine.

Interleukin-6 is a predictor of mortality in stable hemodialysis patients.

BACKGROUND/AIMS: Mortality in end-stage renal disease patients with dialysis remains high. A high percentage of dialysis patients display signs of chronic microinflammation. To clarify whether microinflammation is involved in the high incidence of poor prognosis in dialysis patients, we investigated the association of inflammatory markers with mortality in a prospective observational cohort study. METHODS: 120 patients undergoing hemodialysis were enrolled. Baseline cross-sectional analysis of the relationship between inflammatory markers [interleukin-6 (IL-6), tumor necrosis factor-alpha and high-sensitivity C-reactive protein] and other factors, along with a survival analysis for death, were performed. All subjects were divided into 2 groups according to the median value of IL-6. RESULTS: The mortality rate was significantly higher in the high (20.0%) compared with the low IL-6 group (3.3%, p = 0.0046). Receiver-operating characteristic curves indicated high mortality to be closely associated with a high IL-6 level rather than tumor necrosis factor-alpha. In stepwise multiple regression analyses, age, phosphorus and high-sensitivity C-reactive protein were independent predictors of IL-6 (R(2) = 0.466, p < 0.0001). CONCLUSIONS: These data clearly show that plasma IL-6 is a powerful predictor of all-cause mortality in dialysis patients.

Switching from calcium carbonate to sevelamer hydrochloride has suppressive effects on the progression of aortic calcification in hemodialysis patients: assessment using plain chest X-ray films.

Sevelamer hydrochloride, a non-aluminum- and non-calcium-containing hydrogel, is an effective phosphate binder in dialysis patients. The suppressive effect of the switching from calcium carbonate to sevelamer hydrochloride on the progression of vascular calcification was examined by measuring areas of calcification on routine chest X-rays using image-analyzing software. The data of 69 maintenance hemodialysis patients were analyzed retrospectively. Over a period of 18 months, 19 patients took only sevelamer hydrochloride as a phosphate binder, while the other 50 patients took only calcium carbonate. The area of calcification increased in the calcium carbonate group, but did not change significantly in the sevelamer group. While the usefulness of computed tomography in detecting vascular calcification in hemodialysis patients has been reported previously, the suppressive effects of switching from calcium carbonate to sevelamer hydrochloride on the progression of aortic calcification can be observed without computed tomography by using the plain chest X-ray films that are routinely performed in hemodialysis clinics.

[Anaphylactic reaction to latex during spinal anesthesia: a case report].

A 46-year-old man, with a history of atopic dermatitis and bronchial asthma, underwent surgery for an inguinal hernia. Forty-three minutes subsequent to spinal anesthesia, the patient complained suddenly of dyspnea with wheezing. Blood pressure decreased and skin eruption was observed on his chest. Postoperative laboratory tests revealed high IgE concentration, and a skin test confirmed an allergy to latex. The patient's allergic reaction was easily overlooked because of his history of bronchial asthma and the possibility that the hypotension was caused by the high spinal anesthesia. Latex allergy should be considered in any suspicious case presenting with these symptoms during surgery. After recovery, a skin test should be used to confirm the allergy to avoid repeated allergic episodes.

[Awareness during anesthesia with sevoflurane: a case report].

We report a case of a patient who experienced awareness during general anesthesia with sevoflurane. A 71-year-old man, weighing 57 kg, was operated on for a malignant tumor of the parotid gland. He was given 2 mg diazepam orally as a premedication. General anesthesia was induced by thiamylal 200 mg, fentanyl 50 microg, and up to 5% of sevoflurane. Muscle relaxation was obtained with vecuronium 6 mg, and the patient was intubated. After induction, fentanyl 150 microg was added, but no other intravenous anesthetics or muscle relaxants were used. The end-expiratory concentration of sevoflurane was maintained at 0.8% to 1.7% before the start of surgery, and 1.5% to 2.9% during surgery. The operation lasted for 10.4 hours. His left eye was guarded by ointment but kept open for observation by the surgeon of facial movement following muscle stimulation. The surgical course, emergence, and the postoperative course were uneventful. On the fifth postoperative day, the patient started to describe his visual memory during the operation, although he did not remember any pain or discomfort. We believe that visual input through his open eyes, the effect of cranial bone oscillation by the surgery, and the idiosyncrasy of the patient contributed to his intraoperative recall.

Erythemas caused by electrodes while monitoring neuromuscular blockade: three cases.

Skin erythemas formed in three patients during surgery at the sites where negative electrodes had been attached to stimulate the ulnar nerve for a neuromuscular transmission monitor (Relaxograph). The patients were all women, aged 52, 62, and 74 years, and general anesthesia lasted 8 h 20 min, 4 h 50 min, and 8 h 45 min, respectively. The electrodes used were disposable ECG electrodes in the first two patients and one designed for a neuromuscular monitor in the third; all were carbon-coated and then covered with gel. However, when the electrodes were detached from the lesion, they all showed loss or damage of the carbon coating under the gel. We recommend balancing the merit of monitoring with the risk of complications, even when applying an apparently safe, noninvasive monitor.

[Perioperative failure of hemodialysis shunts: analysis of risk factors].

BACKGROUND: Because vascular access dysfunction results in substantial morbidity in patients undergoing chronic hemodialysis, this complication should be avoided. However, we experienced four patients whose hemodialysis shunts failed within 24 hours postoperatively. METHODS: We retrospectively analyzed operations performed under general anesthesia in our hospital for patients receiving hemodialysis shunts between May 2001 and October 2002. Comparisons between cases with and without perioperative shunt failures were performed using Mann-Whitney and Fishers exact tests. RESULTS: Spinal surgery (P<0.01) and surgery placed in prone or knee-chest positions (P<0.05) were significantly more frequent, and the operation times (P<0.01) and blood losses (P<0.05) were significantly greater, in the occluded group (n=4) than in the non-occluded group (n=12). CONCLUSIONS: Prone position might have impaired venous backflow from the shunt, thus promoting thrombogenesis. Additionally, moderate hemorrhage, with or without blood transfusion, may have induced a transient hypercoagulable state during the operation, which thus contributed to the acute shunt failure.

[Airway management in tracheal stenosis caused by malignant goiter].

We report a case of malignant goiter with severe tracheal stenosis. The patient was a 61-year-old female, who had orthopnea on admission. Radiological examinations revealed a tracheal stenosis extending from 4.5 cm to 8 cm below the glottis; the smallest caliber being 5 mm. On the seventh day after admission, the patient complained of dyspnea even while sitting. An emergency tracheotomy was scheduled. While the patient was awake in a sitting position, a fiberscope was inserted endotracheally to confirm the intact inner surface of the trachea, and then an armored endotracheal tube (outer diameter 9.2 mm, inner diameter 6.5 mm) was inserted. Unexpectedly, the tube could be advanced through the stenosis without resistance. After induction of general anesthesia, the patient was placed in a supine position, and a tracheotomy was performed. This case demonstrates that, while intubation of the trachea through a stenosis is sometimes dangerous, it may be indicated when the inner surface of the trachea is intact and a tube with an inner diameter greater than 5 mm can then be placed.

Comparison of postoperative liver dysfunction following halothane and sevoflurane anesthesia in women undergoing mastectomy for cancer.

The incidence of an abnormal increase in the serum levels of glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) following anesthesia with halothane and 65% nitrous oxide in oxygen (halothane group) or with sevoflurane and 65% nitrous oxide in oxygen (sevoflurane group) was compared in women undergoing surgery for breast cancer. An abnormal increase in GOT and GPT, both defined as higher than 50 IU, occurred postoperatively in 2 of the 150 patients (1.7%) in the sevoflurane group, and in 37 of the 200 (18.5%) in the halothane group (P<0.001). The elevated levels of serum transaminases after sevoflurane ranged from 50 to 65 IU whereas those after halothane ranged from 50 to 1000 IU, except for a value greater than 5000 IU in 1 patient. In the halothane group, there was a significant association between postoperative increases in serum transaminases and previous exposure to inhalation anesthetics, postoperative mitomycin therapy, and radiation therapy (all P<0.001). The results of multivariate analysis, when data from all patients were taken together, showed that the type of anesthetic (halothane) was the highest factor related to postoperative increases in GOT and GPT (odds ratio 35.85; 95% confidence interval 5.92-217.37), followed next by prior exposure to inhalation anesthetics (8.65; 2.96-25.27), postoperative radiation therapy (4.37; 1.70-11.19), and postoperative mitomycin therapy (3.56; 1.23-10.35). These data suggest that sevoflurane is less likely to cause anesthesia-related liver dysfunction than halothane.