Short-Term Outcomes of ABO-Incompatible Living Donor Kidney Transplantation With Uniform Protocol: Significance of Baseline Anti-ABO Titer

Antibody-mediated rejection (AMR) is one of the major causes of poor outcomes in ABO-incompatible kidney transplantation (ABOi KT). Studies investigating AMR risk factors found that anti-ABO titer is a major issue. However, the significance of antibody titer has been debated. This retrospective study analyzed AMR risk factors in 59 patients who underwent ABOi KT between August 2010 and January 2015. We also analyzed AMR risk factors in recipients with high anti-ABO baseline titers (≥1:64 on dithiothreitol at 37°C phase or ≥1:256 on antihuman globulin phase). The 2-year patient survival rate was 95.8%, and the 2-year graft survival rate was 94.9%. Nine patients (15.3%) experienced clinical (6 of 59 [10.2%]) or subclinical (3 of 59 [5.1%]) AMR. One patient experienced graft loss from hyperacute rejection. AMR risk factor analysis revealed that baseline antibody titer was associated with incidence of AMR. In patients with high baseline titers, low doses of rituximab (200-mg single-dose), an antibody against CD20, was predictive for AMR. Six patients who received pretransplant intravenous immunoglobulin did not experience AMR even when they had high baseline antibody titers. Our results indicate that a high baseline antibody titer affected the incidence of AMR. ABOi KT candidates with high baseline titers need to undergo an intensified preconditioning protocol, including high-dose rituximab (375 mg/m(2)) and intravenous immunoglobulin.

Time interval to conversion of interferon-gamma release assay after exposure to tuberculosis

The proper interval for repeating an interferon-γ release assay (IGRA) among tuberculosis contacts with initially negative results is unknown. The interval for IGRA conversion after exposure to patients with active pulmonary tuberculosis in an outbreak setting was evaluated. In a platoon of 32 soldiers, four active pulmonary tuberculosis patients, in addition to one index patient, were diagnosed during a contact investigation. For the other 27 contacts, a tuberculin skin test (TST) and QuantiFERON® TB-Gold In-Tube (QFT-GIT) assay were performed. For soldiers with a negative result on the initial QFT-GIT assay, the test was repeated at 2, 4, 8, 14, 18 and 30 weeks until positive conversion occurred. When conversion was identified, the subject was treated for latent tuberculosis infection. Initially, 17 (63.0%) soldiers gave positive QFT-GIT results, whereas 21 (77.8%) showed positive TST results. Among 10 participants with initially negative QFT-GIT results, three showed conversion at 2 weeks, three at 4 weeks and three at 14 weeks. Conversion did not occur during the 30-week observation period in one contact. Based on the tuberculosis exposure time-points among the contacts, IGRA conversion generally occurred 4-7 weeks after exposure, although it could occur as late as 14-22 weeks after exposure.

Intraductal papillary mucinous tumour of the pancreas: differentiation of malignancy and benignancy by CT

AIM

To retrospectively identify signs predictive of malignant intraductal papillary mucinous tumour (IPMT) of the pancreas on computed tomography (CT) images.

MATERIALS AND METHODS

Thirty-four benign and 21 malignant pancreatic IPMTs were evaluated. Preoperative helical CT images in these 55 cases of pathologically proven pancreatic IPMT were reviewed by two radiologists unaware of the histological grading. Tumour morphological types, locations, numbers and sizes of cystic lesions, maximum main pancreatic duct diameters, the presence of septa, mural nodule, wall thickening, and calcification in cysts, communication with the main pancreatic duct, peripancreatic haziness, protrusion of duodenal papilla, pancreatic atrophy, lymphadenopathy and distant metastasis were analysed using univariate and multivariate analysis.

RESULTS

Main duct IPMTs were more likely to be malignant (71%) than branch duct (23%) or combined type IPMTs (28%; p=0.002). Among the branch duct type and combined types, large cystic lesion (p=0.018), the presence of a mural nodule (p=0.018), a thickened wall (p=0.009), and peripancreatic haziness (p=0.039) were found to predict malignancy.

CONCLUSION

CT is helpful in the preoperative differentiation of malignant and benign pancreatic IPMT. The presence of a dilated main pancreatic duct, mural nodules, thickened wall and peripancreatic haziness may be used as independent predictive signs of malignancy.

Increased expression of caveolin-1 and microvessel density correlates with metastasis and poor prognosis in clear cell renal cell carcinoma

OBJECTIVE

To investigate the relationship of caveolin-1 expression and microvessel density (MVD), a reflection of angiogenesis, with metastasis and prognosis in patients with clear cell renal cell carcinoma (RCC).

PATIENTS AND METHODS

Formalin-fixed, paraffin-embedded tissue sections of clear cell RCC from 67 patients who had undergone radical nephrectomy were stained immunohistochemically with specific antibodies against caveolin-1 and CD34. Caveolin-1 immunostaining was semi-quantitatively estimated based on the proportion (percentage of positive cells) and intensity. MVD was determined with CD34-stained slides. The expression pattern of caveolin-1 and MVD was compared with the clinicopathological variables.

RESULTS

Eighteen patients had either synchronous or metachronous metastases and 11 died during the follow-up. Caveolin-1 intensity was significantly correlated with tumour size (P = 0.005), TNM stage (P = 0.028), M stage (P = 0.012), grade (P = 0.015), and metastasis (synchronous or metachronous; P < 0.001). The caveolin-1 proportion (P = 0.037) and MVD (P = 0.011) were significantly correlated with metastasis. MVD was correlated with caveolin-1 intensity (r = 0.385, P = 0.001) and caveolin-1 proportion (r = 0.388, P = 0.001). There was no difference in the expression of caveolin-1 and MVD between primary and metastatic sites. The survival of patients with higher caveolin-1 intensity was significantly worse than that of patients with lower caveolin-1 intensity. Multivariate analyses indicated that only M-stage was an independent prognostic factor for cancer-specific survival and caveolin-1 expression was not an independent factor.

CONCLUSIONS

Increased expression of caveolin-1 and MVD is associated with metastasis and a worse prognosis in clear cell RCC. Caveolin-1 expression is correlated with MVD. These results suggest that caveolin-1 may be important in the progression of clear cell RCC and angiogenesis may be affected by caveolin-1 during the progression of RCC.

Improvement of tagatose conversion rate by genetic evolution of thermostable galactose isomerase

To enhance the isomerization rate of galactose into tagatose, a thermostable galactose isomerase, which was isolated from bacteria growing in a hot spring, was genetically improved using the error-prone PCR method. From 500 mutant clones, a clone showing improved conversion activity was selected. The sequence of the selected clone had five amino acid changes: His(228)-->Asp, Gly(384)-->Asp, Ser(393)-->Thr, Lys(428)-->Asn and Asp(475)-->Lys. The improved galactose isomerase had an 11-fold higher reaction rate than the original.

Low-frequency collective chain dynamics in a model biomembrane

Proton NMR was employed as a probe for the collective hydrocarbon chain dynamics in decylammonium chloride (C10H21NH3Cl), a model biomembrane undergoing an irreversible structural phase transition sequence. Our rotating frame spin-lattice relaxation measurements revealed a low-frequency critical collective chain dynamics in the kHz regime, which is associated with the interdigitated to noninterdigitated chain configurational phase transition.

Fluorescein dermofluorometry for the assessment of diabetic microvascular disease

BACKGROUND/AIMS

Fluorescein dermofluorometry can be used to relate the uptake of fluorescein in the skin to blood flow. We have characterized the uptake of the dye by a wash-in time constant that is inversely proportional to the local blood flow. The purpose of this study was to explore the use of dermofluorometry in the assessment of patients with diabetic microvascular disease.

METHODS

Fluorescein dermofluorometry was performed in four groups of patients: non-diabetic control patients, diabetic control patients, diabetic patients with chronic foot ulcers, and diabetic patients with acute foot ulcers. The outcomes of the patients with foot ulcers were documented 4-14 months after participation. Following an intravenous injection of sodium fluorescein, the change in the fluorescein signal with time was continuously measured at the plantar surface of the foot. Both the initial slope of the signal and the wash-in time constant were calculated in each subject.

RESULTS

Significant differences in the wash-in time constant were found between diabetic and non-diabetic subjects and between diabetic subjects with and without foot ulcers. Of the eight patients with foot ulcers, two of them did not display an early wash-out in the dermofluorometer signal and later both required amputations.

CONCLUSION

The fluorescein wash-in time constant demonstrated better correlation with the presence of diabetic microvascular disease than did the initial slope of the signal. Differences in the wash-in time constants of non-diabetic and diabetic subjects support the hemodynamic hypothesis for the development of microvascular disease. The indication of early wash-out of the fluorescein signal may also be useful in the prediction of ulcer healing.

Increased erythritol production in fed-batch cultures of Torula sp. by controlling glucose concentration

The effect of glucose concentration on erythritol production by Torula sp. was investigated. The maximum volumetric productivity of erythritol was obtained at an initial glucose concentration of 300 g l(-1) in batch culture. The volumetric productivity was maximal at a controlled glucose concentration of 225 g l(-1), reducing the lag time of the erythritol production. A fed-batch culture was established with an initial glucose concentration of 300 g l(-1) and with a controlled glucose concentration of 225 g l(-1) in medium containing phytic acid as a phosphate source. In this fed-batch culture, a final erythritol production of 192 g l(-1) was obtained from 400 g l(-1) glucose in 88 h. This corresponded to a volumetric productivity of 2.26 g l(-1) h(-1) and a 48% yield.

Biological modification of the fatty acid group in an emulsan by supplementing fatty acids under conditions inhibiting fatty acid biosynthesis

When the concentration of the antibiotic cerulenin was increased up to 3.0 mg/l in medium containing ethanol as a carbon source, the specific growth rate of Acinetobacter calcoaceticus and the fatty acid content of the emulsan decreased from 0.179 h(-1) and 13.9% to 0.015 h(-1) and 3.4%, respectively. The emulsifying activity in medium containing cerulenin decreased with increasing cerulenin concentration. In the culture containing 3.0 mg/l cerulenin, fatty acid biosynthesis was inhibited. Various fatty acids were added to this inhibitory culture as a second carbon source to modify the fatty acid group in the emulsan. When an odd-numbered fatty acid was added, the resulting emulsan was found to have other odd-numbered fatty acids that were not present originally. Among the emulsan produced from even-numbered fatty acids, the emulsan produced from myristic acid (C14) contained the greatest amount of the same-numbered fatty acids. When the amount of supplemental myristic acid was increased, the myristic acid content in the emulsan increased, but its emulsifying activity decreased.

Increase of xylitol yield by feeding xylose and glucose in Candida tropicalis

Candida tropicalis, a strain isolated from the sludge of a factory manufacturing xylose, produced a high xylitol concentration of 131 g/l from 150 g/l xylose at 45 h in a flask. Above 150 g/l xylose, however, volumetric xylitol production rates decreased because of a lag period in cell growth. In fed-batch culture, the volumetric production rate and xylitol yield from xylose varied substantially with the controlled xylose concentration and were maximum at a controlled xylose concentration of 60 g/l. To increase the xylitol yield from xylose, feeding experiments using different ratios of xylose and glucose were carried out in a fermentor. The maximum xylitol yield from 300 g/l xylose was 91% at a glucose/xylose feeding ratio of 15%, while the maximum volumetric production rate of xylitol was 3.98 g l-1 h-1 at a glucose/xylose feeding ratio of 20%. Xylitol production was found to decrease markedly as its concentration rose above 250 g/l. In order to accumulate xylitol to 250 g/l, 270 g/l xylose was added in total, at a glucose/xylose feeding ratio of 15%. Under these conditions, a final xylitol production of 251 g/l, which corresponded to a yield of 93%, was obtained from 270 g/l xylose in 55 h.

Increase of xylitol production rate by controlling redox potential in Candida parapsilosis

The effect of redox potential on xylitol production by Candida parapsilosis was investigated. The redox potential was found to be useful for monitoring the dissolved oxygen (DO) level in culture media, especially when the DO level was low. An increase in the agitation speed in a 5 L fermentor resulted in an increased culture redox potential as well as enhanced cell growth. Production of xylitol was maximized at a redox potential of 100 mV. As the initial cell concentration increased from 8 g/L to 30 g/L, the volumetric productivity of xylitol increased from 1.38 g/L. h to 4.62 g/L. h. A two-stage xylitol production strategy was devised, with stage 1 involving rapid production of cells under well-aerated conditions, and stage 2 involving cultivation with reduced aeration such that the culture redox potential was 100 mV. Using this technique, a final xylitol concentration of 180 g/L was obtained from a culture medium totally containing 254.5 g/L xylose in a 3,000 L pilot scale fermentor after 77 h fermentation. The volumetric productivity of xylitol during the fermentation was 2.34 g/L. h.

Measurement of sodium fluorescein wash-in time constants in subjects with peripheral vascular disease

The authors developed a noninvasive two-channel dynamic dermofluorometer that can quantitatively follow the rapid skin wash-in kinetics of a fluorescent dye to provide an assessment of local skin perfusion. The dermofluorometer was tested in normal subjects and diabetic patients with and without peripheral vascular disease. After an intravenous injection of 1-2 mL of a 10% solution of sodium fluorescein (1.1-2.8 mg/kg), the fluorescent signal was monitored from two sites on the skin surfaces of the forearm and foot. A 3.2-mm-diameter glass fiberoptic bundle was used both to transmit the excitation light (489 nm) and to receive the fluorescent emission (517 nm). Dermofluorometer readings were recorded approximately every second for 10-15 minutes following the injection. The time course of the fluorescein signal intensity was fit to a single exponential curve characterized by a wash-in time constant. There was no significant difference in arm wash-in time constants. Foot wash-in time constants were increased in diabetic patients who had past histories of foot ulcers relative to diabetic patients without a history of foot ulcers (3.2 vs 1.6 min., p < 0.05). Foot wash-in time constants were decreased in diabetic patients who had active infected foot ulcers. This study demonstrates the ability of the dynamic dermofluorometer to measure wash-in constants that reflect the local skin perfusion in less than 15 minutes after a low intravenous dose of sodium fluorescein.

Effect of soybean oil and glucose on sophorose lipid fermentation by Torulopsis bombicola in continuous culture

The effect of soybean oil and glucose on the growth of Torulopsis bombicola and sophorose lipid production in continuous culture was investigated. As the dilution rate in 100 g/l glucose and 100 g/l soybean oil medium was increased, the dry cell weight and sophorose lipid concentration decreased. Sophorose lipid productivity, however, was maximum at a dilution rate of 0.03 h-1. The cell yield from glucose and the sophorose lipid production from soybean oil were approximately constant regardless of the dilution rate. The specific consumption rate of soybean oil was closely related to the specific production rate of sophorose lipid. These results suggest that soybean oil was used only for sophorose lipid production whereas glucose was used only for cell mass and maintenance. When the soybean oil concentration was varied at fixed dilution rate in 100 g/l glucose medium, a high concentration of soybean oil was found to inhibit sophorose lipid production.

Monitoring pH of otitis media effusion in chinchillas using fluorescence spectroscopy

We have developed a fiber optic fluorometer to measure fluorescent signal intensities across an epithelium barrier. As a medically relevant example, we have measured the pH of the effusion formed during Hemophilus influenzae induced otitis media infection in the chinchilla, the classical animal model for human middle ear disease. Because the choice of antibiotic used in clinical therapy is dependent on the pH of the effusion, a noninvasive method of measuring pH is highly desirable. Using the fluorescent pH probe carboxy-seminapthorhodafluor, we were able to detect pH changes of 0.15 units in the pH range around 7.0. The development and resolution of the otitis media was followed with magnetic resonance imaging to confirm the presence of the effusion formed during the infection.