Small-for-size grafts in living-related liver transplantation

BACKGROUND

The problems associated with small-for-size grafts in living-related liver transplantation are not fully understood.

STUDY DESIGN

A consecutive series of 79 patients underwent 80 living-related liver transplantation procedures, including one retransplant, at the University of Tokyo from January 1996 to January 2000. They were divided into two groups by graft size: graft weight/recipient standard liver volume ratios of 40% or less (n = 24), and more than 40% (n = 56). Preoperative status, mortality, morbidity, duration of hospital stay, and postoperative graft function were examined and compared between the groups.

RESULTS

The rate of patients who were restricted to the intensive care unit preoperatively was comparable between the groups (33% versus 21%, p = 0.27). The mean standard liver volume ratios were 37% in the small graft group and 84% in the large group. Survival rates were 80% (5 of 24) for the small graft group, which was significantly lower than that for the large group (96%, 54 of 56, p = 0.02). The rate of acute rejection was comparable between the groups (33% versus 43%, p = 0.47). Vascular complication was observed in 17% of the small graft group patients and 23% of the large group (p = 0.77). No difference was observed in the frequency of bile leakage or bile duct stenosis (25% versus 21%, p=0.77). Hyper-bilirubinemia and elongation of prothrombin time persisted longer in the small graft group than in the large group (p < 0.0001 for both).

CONCLUSIONS

Our surgical results may suggest that a graft weight ratio of 40% or less provides a lower chance of survival after living-related liver transplantation.

Role of nitric oxide in focal microcirculation disorder of guinea pig cochlea

This study was designed to evaluate the role of endogenous nitric oxide (NO) in focal microcirculation disorder of the guinea pig cochlea. Focal microcirculation disorder was induced by a photochemical reaction at the lateral wall of the second cochlear turn. Saline or N omega-nitro-L-arginine methyl ester (L-NAME) was administered before the onset of photochemical reaction. Cochlear blood flow (CBF) was measured at the focal lesion (ischemic core), 1 mm from the lesion in the apical and basal direction (ischemic border zone) by using a novel non-contact laser blood flowmeter. NO synthase activities were measured by radioenzymeassay. In the saline pretreatment group, CBF was significantly decreased to 58.8+/-4.4% of the baseline at the ischemic core 30 min after the onset of photochemical reaction (P<0.01), while CBF showed no significant change at the ischemic border zone. In the L-NAME pretreatment group, CBF was significantly decreased not only at the focal lesion (48.3+/-6.5%, P<0.01), but also at the ischemic border zone (apical, 49.3+/-2.3%, P<0.05; basal, 58.7+/-7.1%, P<0.05, respectively). NO synthase III activity of cochlea was increased significantly (P<0.01) 15 min after microcirculation disorder. These findings suggest that formation of endogenous NO plays a key role in the maintenance of CBF in acute focal cochlear microcirculation disorder.

Liver transplantation using a right lateral sector graft from a living donor to her granddaughter

One of the major concerns regarding living-related liver transplantation is graft-size disparity. The left liver graft is too small while the right is too large in some recipients. To overcome this problem, the right lateral sector (Segments VI and VII) was transplanted from a living donor (55 kg) to her granddaughter (17 kg). The common hepatic trunk had to be anastomosed end-to-end to the graft hepatic vein without being compressed by the graft overriding the vena cava and without unfavorable tension of the anastomosis. The anterior wall of the hepatic vein of the donor was resected as much as possible. The superficial left, left, middle and right hepatic veins of the recipient were made confluent by incision of the intervening venous walls, and the nicks were sutured to form a wide and long common venous trunk. The recipient received a graft corresponding to 75% of her standard liver volume. She was complicated with gastric dilation and acute rejection, but recovered with no signs of anastomotic stricture. Right lateral sector graft obtained by this innovative procedure may be useful for overcoming borderline graft-recipient size and shape differences.

Measurements of thermal effects on four-photon mixing conversion efficiency in an optical fiber

Thermal effects on the conversion efficiency of four-photon mixing (FPM) power in a silica optical fiber are measured. When the temperature of the fiber changes from 9 to 350 degrees C, the first Stokes power decreases with a temperature coefficient of -0.33%/ degrees C as the temperature increases to 200 degrees C and then becomes saturated with a further increase in temperature. This temperature characteristic of the first Stokes power reflects the temperature characteristics of the nonlinear refractive index of the fiber, which are similar to its FPM temperature dependence.

Parasympathetic reflex vasodilatation in rat submandibular gland

The present study was designed to investigate 1) whether parasympathetic reflex vasodilatation occurs in the submandibular gland (SMG) in deeply urethan-anesthetized, cervically vagotomized, and sympathectomized rats when the central cut end of the lingual nerve (LN) is electrically stimulated and 2) to what extent the neural mechanisms underlying such responses are the same as those involved in the response to direct stimulation of the chorda-LN (CLN). Stimulation of each nerve separately elicited a marked blood flow increase in SMG. Section of the chorda tympani abolished the SMG blood flow response but had no effect on the lip blood flow increase evoked by LN stimulation. Section of the CLN abolished the SMG blood flow increases evoked by stimulation of either nerve. The SMG blood flow increases (regardless of whether they were evoked by LN or CLN stimulation) were markedly reduced by the autonomic cholinergic ganglion blocker hexamethonium. The present study demonstrates that a parasympathetic reflex vasodilator mechanism is present in the rat SMG and that it can express its effects under deep general anesthesia.

Ebp2p, yeast homologue of a human protein that interacts with Epstein-Barr virus nuclear antigen 1, is required for pre-rRNA processing and ribosomal subunit assembly

BACKGROUND

A defect in the secretory pathway causes the transcriptional repression of both rRNA and ribosomal protein genes in Saccharomyces cerevisiae, suggesting a coupling of ribosome synthesis and plasma membrane synthesis. Rrs1p, an essential nuclear protein, is required for the secretory response.

RESULTS

EBP2, encoding the yeast homologue of a human protein that interacts with Epstein-Barr virus Nuclear Antigen 1, was cloned in a two-hybrid screen using RRS1 as a bait. The rrs1-1 mutation, which produces Rrs1p without the C-terminal half and causes a defect in the secretory response, almost abolished the interaction with Ebp2p. Ebp2p is essential for growth and is mainly localized in the nucleolus. The effects of Ebp2p depletion on ribosome biogenesis is quite similar to that of Rrs1p depletion; in the Ebp2p-depleted cells, the rate of pre-rRNA processing is slower, and significantly less mature 25S rRNA is produced compared to those in wild-type cells. The polysome pattern indicates that Ebp2p-depletion causes a decrease of 80S monosomes and polysomes, an accumulation of 40S subunits, and the appearance of half-mer polysomes.

CONCLUSIONS

Ebp2p is required for the maturation of 25S rRNA and 60S subunit assembly. Ebp2p may be one of the target proteins of Rrs1p for executing the signal to regulate ribosome biogenesis.

A case of Meniere's disease with vertical nystagmus after administration of glycerol

A 62-year-old woman who complained of repetitive vertigo with a left fluctuating hearing loss was admitted to our hospital three times. A glycerol test was done on the third admission. Two hours after the administration of glycerol, the patient complained of rotatory vertigo with a downbeat vertical nystagmus. This nystagmus then changed its direction upward. Her left hearing loss was improved during the glycerol test. On the day after the glycerol test, a caloric test was done. The caloric response of the right ear was remarkably improved. Although she had not felt a hearing loss in the right ear, an overwritten audiogram showed a fluctuation of hearing in the right ear. The bilateral caloric responses fluctuated. From these findings, it appears that the function of the inner ear on both sides fluctuating. We speculate that the administration of glycerol elicited an asymmetry in the function of the inner ear on both sides and ocuured vertigo with vertical nystagmus because of the irritation of both ears.

Characterization of antigenically unique influenza C virus strains isolated in Yamagata and Sendai cities, Japan, during 1992-1993

Three influenza C virus strains (C/Yamagata/1/92, C/Yamagata/1/93 and C/Miyagi/5/93) isolated in Yamagata and Sendai Cities, Japan, between June 1992 and May 1993 were found to possess haemagglutinin-esterase glycoproteins that were antigenically indistinguishable from one another but were clearly different from any previous Japanese isolates. To investigate the origin of the 1992/1993 strains, their antigenic and genetic properties were compared with those of eight strains isolated outside Japan between 1967 and 1982. The results showed that the 1992/1993 isolates were closely related to a virus isolated in Brazil in 1982 (C/SaoPaulo/378/82) and that these viruses (including C/SaoPaulo/378/82) are reassortants that had obtained PB1 and NP genes from a C/Yamagata/26/81-like parent and the other genes from another as yet unidentified parent.

RRS1, a conserved essential gene, encodes a novel regulatory protein required for ribosome biogenesis in Saccharomyces cerevisiae

A secretory defect causes specific and significant transcriptional repression of both ribosomal protein and rRNA genes (K. Mizuta and J. R. Warner, Mol. Cell. Biol. 14:2493-2502, 1994), suggesting the coupling of plasma membrane and ribosome syntheses. In order to elucidate the molecular mechanism of the signaling pathway, we isolated a cold-sensitive mutant with a mutation in a gene termed RRS1 (regulator of ribosome synthesis), which appeared to be defective in the signaling pathway. The rrs1-1 mutation greatly reduced transcriptional repression of both rRNA and ribosomal protein genes that is caused by a secretory defect. RRS1 is a novel, essential gene encoding a nuclear protein of 203 amino acid residues that is conserved in eukaryotes. A conditional rrs1-null mutant was constructed by placing RRS1 under the control of the GAL1 promoter. Rrs1p depletion caused defects in processing of pre-rRNA and assembly of ribosomal subunits.

Cochlear findings in the white spotting (Ws) rat

White spotting (Ws) rats possess a c-kit gene mutation at the W locus, resulting in a variety of characteristics including a lack of intermediate cells of the stria vascularis. The present study employs a light microscope (LM), scanning (SEM) and transmission electron microscopes (TEM), diaminobenzidine (DAB) staining techniques and auditory brainstem response (ABR) to investigate the structure and function of the cochlea in 26 homozygous Ws/Ws rats aged 1-6 months. A slight thinning of the stria vascularis and moderate elevation of ABR threshold were about the only defects noted in 1 month animals, while older animals displayed various defects that tended to worsen with age. At 3 months LM revealed pigment granules in the basal turn of most animals, with a loss of pigmentation in the upper turns. The stria vascularis and organ of Corti tended to be well preserved in the lower, pigmented portion, while the upper, unpigmented portion showed severe strial degeneration and some outer hair cell loss. DAB staining revealed a well developed strial capillary net throughout the pigmented portion of the cochlea, with severe degradation in the unpigmented apical portion. ABR thresholds were slightly elevated over 1 month values. At 6 months great differences in degeneration were noted between right and left ears of the same animal.

Effect of pretreatment with FTY720 and cyclosporin on ischaemia-reperfusion injury of the liver in rats

The effect of pretreatment with FTY720 (2-amino-2-[2-(4-octylphenyl)ethyl]-1,3-propanediol hydrochloride) or cyclosporin, or both, on neutrophil-mediated injury has been examined by use of a rat model of transient clamping of hepatic flow. Pretreatment with FTY720 alone or with cyclosporin induced a marked reduction of circulatory lymphocytes, whereas the use of these drugs in combination was very effective at suppressing the elevation of the number of peripheral polymorphonuclear neutrophils (PMN) after reperfusion. Pretreatment with cyclosporin, with or without FTY720, significantly reduced hepatic damage, whereas FTY720 alone tended to prolong hepatic damage. Pretreatment of cyclosporin alone, but not in combination with FTY720, significantly reduced the accumulation of PMN and led to lower myeloperoxidase levels in the damaged liver. In conclusion, pretreatment with cyclosporin, with or without FTY720, reduced hepatic damage after warm ischaemia-reperfusion, whereas pretreatment with FTY720 alone tended to prolong this damage.

Influence of tacrolimus on bile acid and lipid composition in continuously drained bile using a rat model. Comparative study with cyclosporine

Cholestatic effects have been reported for cyclosporine (CsA), but information is still limited for tacrolimus (TCR). The purpose of this study was to investigate the influence of TCR on biliary bile acid and lipid composition as compared with CsA, using a continuously bile-drained rat model. Adult male Wistar rats received TCR (0.4 mg/kg, 1 mg/kg, and 4 mg/kg) or CsA (2.5 mg/kg, 10 mg/kg, and 25 mg/kg) by intramuscular injection (i.m.) daily for 10 days. On day 7, the common bile duct of all rats was cannulated, then bile was continuously collected for the following 3 days. Bile flow, bile acid secretion rate (BASR), and biliary lipids secretion were measured for each of the groups. TCR increased bile acid-dependent flow (BADF) but with no statistical significance. However, this agent did not influence total bile flow and biliary lipids secretion, while bile acid-independent flow (BAIF) was significantly reduced and bile acid synthesis (mainly cholic acid, CA, synthesis) was increased. In contrast, CsA was cholestatic, showing a tendency to reduce both BADF and BAIF. BASR was dose-dependently suppressed, especially in chenodeoxycholic acid (CDCA). Furthermore, biliary lipids secretions were also significantly decreased under a higher dose of CsA. TCR increased BADF with no influence on total bile flow, having a stimulating effect on CA production, although CsA dose-dependently diminishes CDCA production and consequently reduced bile secretion. Our results suggest that TCR is a less effective agent on cholestasis as compared to CsA.

Involvement of thioredoxin peroxidase type II (Ahp1p) of Saccharomyces cerevisiae in Mn2+ homeostasis

To identify new proteins involved in Mn2+ homeostasis, we isolated Mn(2+)-resistant mutants of Saccharomyces cerevisiae starting from a calcineurin-deficient, Mn2+ hypersensitive strain (delta cmp1 delta cmp2). The mutations were found to lie in the PMR1 gene, known to encode a "P-type" Ca(2+)-ATPase that transports Ca2+ and Mn2+ from the cytosol to the Golgi apparatus. A second gene, AHP1, was cloned as a suppressor of the Mn2+ tolerance of a delta cmp1 delta cmp2 pmr1 mutant. Ahp1p was recently described as a thioredoxin peroxidase type II, an antioxidant protein with alkyl hydroperoxide defense properties in yeast. AHP1 disruption in strain W303 decreased tolerance to Mn2+ and H2O2. We found that a GFP-Ahp1p fusion construct was in the cytosol when cells were grown in glucose, and in the mitochondria when cells were grown in oleate. Based on Mn2+ transport data, we concluded that Ahp1p is involved in cellular Mn2+ homeostasis in trafficking of Mn2+ from cytosol to mitochondria and from cytosol for export across the plasma membrane.