Abnormal cortical mechanisms of voluntary muscle relaxation in patients with writer's cramp: an fMRI study

Although it is hypothesized that there is abnormal motor inhibition in patients with dystonia, the question remains as to whether the mechanism related to motor inhibition is specifically impaired. The objective of the present study was to clarify the possible abnormalities of the mechanisms underlying voluntary muscle relaxation during motor preparation and execution in patients with writer's cramp, using event-related functional MRI. Eight patients with writer's cramp and 12 age-matched control subjects participated in the study. Two motor tasks were employed as an experimental paradigm. In the relaxation task, subjects were asked to hold their right wrist in the horizontal plane by maintaining moderate contraction of wrist extensor muscles in the premotor phase; they relaxed those muscles voluntarily just once during each fMRI scanning session. In the contraction task, subjects extended the right wrist voluntarily from the same premotor state as for the relaxation task. Five axial images covering the primary sensorimotor cortex (SMC) and supplementary motor area (SMA) were obtained once every second. Activated volumes in the left SMC and the SMA were significantly reduced in patients for both muscle relaxation and contraction tasks. These data suggest that there is impaired activation in both SMC and SMA in voluntary muscle relaxation and contraction in patients with writer's cramp. This implies that abnormalities of both inhibitory and excitatory mechanisms in motor cortices might play a role in the pathophysiology of focal dystonia.

Quantitative effects of respiration on venous return during single knee extension-flexion

Respiration and the muscle pump play major roles in increasing venous return. However, the relative contribution of each of these factors remains unclear. The present study investigates the quantitative effects of interaction between respiration and the muscle pump on femoral venous blood flow (FVBF) during a single voluntary knee extension-flexion (KEF) using duplex-Doppler ultrasound. During various respiration modes, which consisted of arrested respiration, normal respiration and deep respiration (inspiration or expiration), eight subjects performed a supine one-legged voluntary KEF. FVBF was measured during respiration only (Protocol A) and during KEF synchronized with respiration (Protocol B). The difference between FVBF values obtained in Protocol B and Protocol A was defined as DeltaFVBF. When KEF was synchronized with normal or deep respiration, FVBF with inspiration was significantly lower than that with expiration. However, DeltaFVBF was significantly higher with inspiration than with expiration during deep respiration but was not significant during normal respiration. Furthermore, DeltaFVBF was significantly higher at both normal and deep respiration than at arrested respiration. The effects upon the venous return during KEF differed between inspiration and expiration. The present findings indicate that during a single supine KEF, respiration might promote venous return to a range of 1.5- to 2.3-fold DeltaFVBF during arrested respiration.

Clinical intestinal transplantation: a decade of experience at a single center

OBJECTIVE

To assess the long-term efficacy of intestinal transplantation under tacrolimus-based immunosuppression and the therapeutic benefit of newly developed adjunct immunosuppressants and management strategies.

SUMMARY BACKGROUND DATA

With the advent of tacrolimus in 1990, transplantation of the intestine began to emerge as therapy for intestinal failure. However, a high risk of rejection, with the consequent need for acute and chronic high-dose immunosuppression, has inhibited its widespread application.

METHODS

During an 11-year period, divided into two segments by a 1-year moratorium in 1994, 155 patients received 165 intestinal allografts under immunosuppression based on tacrolimus and prednisone: 65 intestine alone, 75 liver and intestine, and 25 multivisceral. For the transplantations since the moratorium (n = 99), an adjunct immunosuppressant (cyclophosphamide or daclizumab) was used for 74 transplantations, adjunct donor bone marrow was given in 39, and the intestine of 11 allografts was irradiated with a single dose of 750 cGy.

RESULTS

The actuarial survival rate for the total population was 75% at 1 year, 54% at 5 years, and 42% at 10 years. Recipients of liver plus intestine had the best long-term prognosis and the lowest risk of graft loss from rejection (P =.001). Since 1994, survival rates have improved. Techniques for early detection of Epstein-Barr and cytomegaloviral infections, bone marrow augmentation, the adjunct use of the interleukin-2 antagonist daclizumab, and most recently allograft irradiation may have contributed to the better results.

CONCLUSION

The survival rates after intestinal transplantation have cumulatively improved during the past decade. With the management strategies currently under evaluation, intestinal transplant procedures have the potential to become the standard of care for patients with end-stage intestinal failure.

Freeze-thawing behaviour of highly concentrated aqueous alkali chloride-glucose systems

The freeze-thawing behaviour of highly concentrated aqueous alkali chloride-glucose systems was investigated by differential scanning calorimetry (DSC). In the aqueous NaCl-glucose solution system, single or double glass transitions followed by the corresponding devitrification exotherms were observed during rewarming. In the aqueous KCl-glucose solution system, on the other hand, a single glass transition followed by an exotherm was observed during rewarming. The presence of double glass transitions observed for a certain composition of the aqueous NaCl-glucose solution was taken as an evidence for the liquid-liquid immiscibility at low temperatures. Two kinds of crystallisation accompanied by exotherms during rewarming were identified by X-ray diffraction as ice and ice/NaCl x 2H(2)O, or ice/KCl eutectic component.

Clinicopathological study of mucous pooling referred to as mucinous component (MUC) in colorectal submucosal invasive carcinomas

We investigated the significance of a pool of mucin, individually termed mucinous component (MUC), at the leading invasion edge of colorectal submucosal invasive carcinoma (SIC). In particular, we studied the correlation between pathological adverse prognostic factors and stainability of the mucosubstances and tumor-associated glycoconjugates in MUC. We demonstrated that MUCs were present in 21% of SICs, and 20% of SICs with MUC were involved in metastasis or recurrence, while only 6% of SICs without MUC were positive for it (p=0.005). SICs with MUC showed strong staining of carcinoembryonic antigen and Ulex europaeus I in the MUCs as well as in the cancer cells with high-grade atypia. Moreover, the mucins in MUCs predominantly stained for sialomucin. This study was the first to investigate the importance of mucous nodules in colorectal SIC. We concluded that MUC in SIC would be an important adverse prognostic factor, and that we should at least consider employing a similar treatment strategy for it to advanced colorectal carcinoma.

Abnormal axonal inward rectifier in streptozocin-induced experimental diabetic neuropathy

In order to explore the pathophysiology of diabetic neuropathy, we studied serial changes of axonal excitability in 20 adult Wistar rats with streptozocin-induced diabetes using the technique of threshold electrotonus (TE). After persistent hyperglycaemia had developed, rats were divided into two groups: nine were fed a diet containing aldose reductase inhibitor (Epalrestat 30 mg/kg/day) (ARI(+) group) and 11 were fed a diet without the inhibitor (ARI(-) group). Eight normal control rats of similar age (NC group) were also studied. We monitored membrane properties of motor axons in the tail for 3 months using TE to measure the changes in excitability induced by subthreshold polarizing currents while recording compound muscle action potentials (CMAPs) in the tail muscle. The ARI(-) group showed a significant increase in CMAP latency 1 month after streptozocin injection, and by 3 months there was significantly lower excitability after hyperpolarization for 100 ms compared with the NC group. A similar change in TE was reproduced by injection of caesium chloride, an inhibitor of inward rectification. By contrast, the ARI(+) group exhibited no significant change in TE or latency at 3 months, although they showed significant body weight loss and hyperglycaemia. These findings indicate that inward rectification is reduced in an experimental model, as in human diabetes, and that blocking the polyol pathway with an ARI prevents this reduction. Reduced inward rectification potentiates conduction block caused by activity-dependent hyperpolarization and may underlie the decreased vibratory sensation seen in the early stage of diabetic neuropathy.

Abdominosacral repair for a rectovaginal fistula with anastomotic stenosis after low anterior resection report of a case

The management of a postoperative rectovaginal fistula after low anterior resection for rectal cancer is difficult and requires reconstruction of the anastomotic site and fistula. The results of reconstructive operation are often unsatisfactory. Herein, we describe our reconstruction technique using the posterior approach through the vaginal lumen for a high rectovaginal fistula repair. This reconstructive operation is useful for postoperative rectovaginal fistulas accompanied by severe stenosis of the anastomotic site following low anterior resection for rectal cancer.

Protective role of the L-arginine-nitric oxide synthase pathway on preservation injury after rat liver transplantation

BACKGROUND

A major problem complicating liver transplantation is the preservation injury that results from cold storage and subsequent ischemia/reperfusion injury after organ revascularization. The L-arginine-nitric oxide (NO) pathway has been recognized to play critical roles during infection, inflammation, organ injury, and transplant rejection. Recent data indicates that NO synthesis has beneficial effects in several models of liver injury. The purpose of this study is to examine the role of the L-arginine-NO pathway on preservation injury in an experimental model of rat liver transplantation.

METHODS

Orthotopic liver transplantation was performed in syngeneic (LEW to LEW) rats. Liver preservation injury was determined by measuring serum liver function tests 6 to 48 hours after transplantation. In some experiments, rats received L-arginine supplementation 0 to 24 hours after transplantation. In other experiments, NO synthase inhibitors (L-NAME or L-NIL) were injected at the time of isograft revascularization.

RESULTS

L-Arginine supplementation decreased hepatic transaminase levels at all time points examined (6-48 hours). L-Arginine produced a significant improvement in liver preservation injury by 12 hours after reperfusion. The NO synthase inhibitor L-NAME caused a significant increase in liver injury 24 hours after injection. The inducible NO synthase (iNOS)-specific inhibitor L-NIL had no significant effect on liver injury.

CONCLUSIONS

The results show that L-arginine supplementation and NO synthesis improve hepatic injury and have a protective role in the transplanted liver graft. The protective effect may be mediated by low-level cNOS-derived NO.

Replicative senescence of biliary epithelial cells precedes bile duct loss in chronic liver allograft rejection: increased expression of p21(WAF1/Cip1) as a disease marker and the influence of immunosuppressive drugs

Early chronic liver allograft rejection (CR) is characterized by distinctive cytological changes in biliary epithelial cells (BECs) that resemble cellular senescence, in vitro, and precede bile duct loss. If patients suffering from early CR are treated aggressively, the clinical and histopathological manifestations of CR can be completely reversed and bile duct loss can be prevented. We first tested whether the senescence-related p21(WAF1/Cip1) protein is increased in BECs during early CR, and whether treatment reversed the expression. The percentage of p21+ BECs and the number of p21+ BECs per portal tract is significantly increased in early CR (26 +/- 17% and 3.6 +/- 3.1) compared to BECs in normal liver allograft biopsies or those with nonspecific changes (1 +/- 1% and 0.1 +/- 0.3; P: < 0.0001 and P: < 0.02), chronic hepatitis C (2 +/- 3% and 0.7 +/- 1; P: < 0.0001 and P: < 0.04) or obstructive cholangiopathy (7 +/- 7% and 0.7 +/- 0.6; P: < 0.006 and P: = 0.04). Successful treatment of early CR is associated with a decrease in the percentage of p21+ BECs and the number of p21+ BECs per portal tract. In vitro, nuclear p21(WAF1/Cip1) expression is increased in large and multinucleated BECs, and is induced by transforming growth factor (TGF)-beta. TGF-beta1 also increases expression of TGF-beta receptor II, causes phosphorylation of SMAD-2 and nuclear translocation of p21(WAF1/Cip1), which inhibits BEC growth. Because conversion from cyclosporine to tacrolimus is an effective treatment for early CR, we next tested whether these two immunosuppressive drugs directly influenced BEC growth in vitro. The results show that cyclosporine, but not tacrolimus, stimulates BEC TGF-beta1 production, which in turn, causes BEC mito-inhibition and up-regulation of nuclear p21(WAF1/Cip1). In conclusion, expression of the senescence-related p21(WAF1/Cip1) protein is increased in BECs during early CR and decreases with successful recovery. Replicative senescence accounts for the characteristic BEC cytological alterations used for the diagnosis of early CR and lack of a proliferative response to injury. The ability of cyclosporine to inhibit the growth of damaged BECs likely accounts for the relative duct sparing properties of tacrolimus.

DYT1 mutation in Japanese patients with primary torsion dystonia

A GAG deletion at position 946 in the DYT1 gene has been identified as one of the gene mutations responsible for autosomal dominant primary torsion dystonia. We examined 178 Japanese patients with various forms of dystonia, and found the mutation in six patients (3.4%) from three families. Five of them had early clinical onset (before age 12) with initial involvement of a limb. To our knowledge, this is the first report of the frequency and the clinical features of DYT1 mutation in oriental patients, and the clinical presentation of the mutation in these patients was similar to that of Jewish or non-Jewish Caucasian patients.

The mystique of hepatic tolerogenicity

The evolution of clinical transplantation has hinged on 2 seminal turning points. The first was the demonstration in 1953 by Billingham, Brent, and Medawar that chimerism-associated tolerance could be induced deliberately in neonatal mice by infusing adult donor hematolymphopoietic cells. This discovery escalated in a straight line over the next 15 years to successful bone marrow transplantation in humans. The second turning point was the demonstration that organ allografts could self-induce tolerance under an umbrella of immunosuppression, or in some species without immunosuppression. Unfortunately, it was incorrectly concluded by most immunologists and surgeons that bone marrow and organ engraftment involved different immune mechanisms. In a derivative error, it became widely believed that the tolerogenicity of the liver differed fundamentally not only from that of bone marrow but also from that of other whole organs. These errors became dogma and were not corrected until low level donor leukocyte chimerism was found in humans and animals bearing long surviving liver, kidney, heart, and other kinds of allografts. With successful bone marrow transplantation, the trace population consisted of recipient rather than donor leukocytes. Thus, the consequences of organ and bone marrow engraftment were mirror images. From these observations, it was proposed that the engraftment of all kinds of organs as well as bone marrow cells (BMC) involved host versus graft (HVG) and graft versus host (GVH) reactions with reciprocal induction of variable degrees of specific non-reactivity (tolerance). The maintenance of the tolerance was an active and ongoing process requiring the persistence of the transplanted fragment of the donor immune system. The immune responsiveness and unresponsiveness to both organ and bone marrow allografts are thought to be governed by the migration and localization of leukocytes. The clarifying principles of tranplantation immunology that have emerged from the chimerism studies are relevant to the adaptive immune response to microbial, tumor, allogeneic, and self antigens. These principles should be used to guide efforts to systematically induce tolerance to human tissues and organs, and perhaps ultimately to xenografts.

Spider silk has an ice nucleation activity

Several ice nucleating substances have been identified, which exist in vivo or can be extracted from biological materials. Spider silk, which has a strong ability for water condensation, has also been found to possess an ice nucleation activity. The freezing temperature of water droplets was higher in the presence than in the absence of spider silk. Moreover, by means of environmental scanning electron microscopy, it was observed that the activity is not due to foreign matter attached to the silk but to the silk fibroin itself.

Endotoxin treatment causes an upregulation of the endothelin system in the liver: amelioration of increased portal resistance by endothelin receptor antagonism

BACKGROUND

Mechanisms underlying hepatic microcirculatory failure during endotoxemia are incompletely understood. Because endothelin-1 (ET-1) has been implicated in endotoxin-induced liver injury, we investigated the hepatic ET-1 system in endotoxin-treated rats.

METHODS

Rats were treated with endotoxin (Escherichia coli lipopolysaccharide; 3 mg/kg, i.p.), and various determinations were made 24 h later.

RESULTS

Endotoxin treatment caused 11.2 +/- 1.6% weight loss, a decrease in mean arterial pressure (MAP; 96 +/- 5 mmHg vs 108 +/- 3 mmHg; P < 0.05) and an increase in portal pressure (11.6 +/- 1.3 mmHg vs 7.4 +/- 1 mmHg; P < 0.02). No significant changes in the serum levels of liver enzymes or hepatocellular necrosis were observed. Endotoxin caused increases in hepatic ET-1 (from 345 +/- 31 to 565 +/- 38 pg/g; P < 0.01), ET-1 receptor density (from 179 +/- 16 to 340 +/- 26 fmol/mg; P < 0.02), and mRNA expression of preproendothelin-1, and ET(A) and ET(B) receptors. While the serum nitric oxide (nitrite +/- nitrate) concentration was increased in endotoxin-treated rats, that of ET-1 remained unchanged. A mixed ET(A)/ET(B) receptor antagonist, TAK-044 (10 mg/kg, i.v.), reduced the weight loss from 11.2 +/- 1.6% to 5.9 +/- 2.9% (P < 0.05) and the portal pressure from 11.6 +/- 1.3 mmHg to 8.6 +/- 0.7 mmHg (P < 0.05) in endotoxin-treated rats. The mixed ET(A)/ET(B) receptor antagonist also caused an increase in serum ET-1 concentration, but did not affect serum nitric oxide and MAP in endotoxin-treated rats.

CONCLUSIONS

These results suggest that the upregulated hepatic ET-1 system is an important mechanism of increased portal resistance and related complications of endotoxemia.

Immunomodulation for intestinal transplantation by allograft irradiation, adjunct donor bone marrow infusion, or both

BACKGROUND

The passenger leukocytes in the intestine have a lineage profile that predisposes to graft-versus-host disease (GVHD) in some animal models and have inferior tolerogenic qualities compared with the leukocytes in the liver, other solid organs, and bone marrow. Elimination by ex vivo irradiation of mature lymphoid elements from the bowel allografts is known to eliminate the GVHD risk. We hypothesized that infusion of donor bone marrow cells (BMC) in recipients of irradiated intestine would improve tolerogenesis without increasing the risk of GVHD.

METHODS

Orthotopic small intestine transplantation was performed with the GVHD-prone Lewis (LEW)-to-Brown Norway (BN) combination and the reverse GVHD-resistant BN-to-LEW model under a short course of tacrolimus treatment (1 mg/kg/day, days 0-13, 20, 27). Grafts were irradiated ex vivo, using a 137Cs source. In selected experimental groups, donor BMC (2.5 x 10(8)) were infused on the day of small intestine transplantation.

RESULTS

The unmodified LEW intestine remained intact, whether transplanted alone or with adjunct donor BMC infusion, but all of the BN recipients died of GVHD after approximately 2 months. Intestinal graft irradiation (10 Gy) effectively prevented the GVHD and prolonged survival to 92.5 days, but all of the BN recipients died with chronic rejection of the LEW grafts, which was prevented by infusion of adjunct donor BMC without causing GVHD. In the GVHD-resistant reverse strain direction (BN-->LEW), all intestinal recipients treated for 27 days with tacrolimus survived > or =150 days without regard for graft irradiation or adjunct BMC, but chronic rejection was severe in the irradiated intestine, moderate in the unaltered graft, and least in the irradiated intestine transplanted with adjunct BMC. Mild arteritis in the 150 day allografts of both strain combinations (i.e., LEW--> BN and BN-->LEW) may have been irradiation associated, but this was prevented when weekly doses of tacrolimus were continued for the duration of the experiment rather than being stopped at 27 days.

CONCLUSIONS

Recipients are protected from GVHD by irradiating intestinal allografts, but the resulting leukocyte depletion leads to chronic rejection of the transplanted bowel. The chronic rejection is prevented with adjunct donor BMC without causing GVHD. Although application of the strategy may be limited by the possibility of radiation injury, the results are consistent with the paradigm that we have proposed to explain organ-induced graft acceptance, tolerance, and chronic rejection.

Ileosigmoid anastomosis with exclusion of transected ileal loop for intestinal fistula following total cystectomy of bladder cancer. Report of a case

We report in this article a new technique of surgical treatment of enterocutaneous or enterovaginal fistula after total cystectomy for three cases of bladder cancer. The surgical outcome was successful in these patients, showing good performance status after this operation. It would seem that this technique is a good indication for enteric fistulas in the bottom of the pelvic cavity, which were difficult to be managed even under the control of total parenteral nutrition.

Donor and recipient leukocytes in organ allografts of recipients with variable donor-specific tolerance: with particular reference to chronic rejection

We have attributed organ engraftment to clonal exhaustion-deletion of host-versus-graft and graft-versus-host reactions that are reciprocally induced and governed by migratory donor and recipient leukocytes. The so-called donor passenger leukocytes that migrate from the allograft into the recipients have been thoroughly studied (chimerism), but not the donor leukocytes that remain in, or return to, the transplanted organ. Therefore, using flow cytometry we determined the percentage and lineages of donor leukocytes in cell suspensions prepared from Lewis (LEW) cardiac allografts to 100 days posttransplantation. The LEW hearts were transplanted to naïve untreated Brown Norway (BN) recipients (group 2), to naïve BN recipients treated with a 28-day or continuous course of tacrolimus (TAC) (groups 3 and 4), and to drug-free BN recipients pretolerized by earlier bone marrow cell (BMC) or orthotopic LEW liver transplantation (groups 5 and 6). The findings in the heart cell suspensions were correlated with the results from parallel histopathologic-immunocytochemical studies and other studies of the grafts and of host tissues. Although the LEW heart allografts were rejected in 9.6 days by the unmodified recipients of group 2, all beat for 100 days in the recipients of groups 3 through 6. Nevertheless, all of the long-surviving cardiac allografts (but not the isografts in group 1) were the targets of an immune reaction at 5 days, reflected by dramatic increases in the ratio of leukocytes to nonleukocyte nucleated cells from normal values of 1:5-1:6 to 1:1-5:1 and by manifold other evidence of a major inflammatory event. The acute changes returned to baseline by 100 days in the chronic rejection (CR) free hearts of groups 4 and 6, but not in the CR-afflicted hearts of short-course TAC group 3 or the less-severely damaged hearts of the BMC-prime group 5. The freedom from CR in groups 4 and 6 was associated with a large donor contribution to the intracardiac leukocyte population at 5 days (28.6% and 22% in the respective groups) and at 100 days (30.5% in group 4 and 8.4% in group 6) compared with 2% and 1.2% at 100 days in the CR-blighted allografts of the partially tolerant animals of groups 3 and 5. Whether large or small, the donor leukocyte fraction always included a subset of class II leukocytes that had histopathologic features of dendritic cells. These class II(+) cells were of mixed myeloid (CD11b/c(+)) and lymphoid lineages; their migration was markedly inhibited by TAC and accelerated by donor-specific priming and TAC discontinuance. Although a large donor leukocyte population and a normal leukocyte/nonleukocyte cell ratio were associated with freedom from CR, these findings and the lineage profile of the intracardiac leukocytes were not associated with tolerance in the animals of groups 3 and 4 under active TAC treatment. The findings in this study, singly and in their entirety, are compatible with our previously proposed leukocyte migration-localization paradigm of organ allograft acceptance and tolerance.

[A complication with hepatic arterial infusion chemotherapy--a case of sepsis related to catheter tip dislocation to the duodenal bulb]

Extra-arterial dislocation of a catheter is one of the complications with hepatic arterial infusion chemotherapy. The authors report a case of sepsis related to catheter tip dislocation to the duodenal bulb. A 69-year-old man underwent sigmoidectomy for sigmoid colon cancer and partial hepatectomy for synchronous metastasis to the liver. We performed hepatic arterial catheterization via the femoral artery, and the patient underwent prophylactic hepatic arterial infusion chemotherapy with 5-FU. Thirty months later, computed tomography during arteriography (CTA) using a port system revealed the dislocation of catheter tip to the duodenal bulb. He showed no symptoms, so we kept him under observation. Sepsis occurred because of the dislocated catheter 39 months later. After removal of the catheter, the symptoms of sepsis disappeared.

Abnormal premovement gating of somatosensory input in writer's cramp

One characteristic of focal dystonia is the sensory trick, by which sensory input to a certain area of the body can reduce abnormal contractions in muscles nearby. This suggests that adjusting the link between sensory input and movement allows motor commands to be issued more effectively from the brain. To explore this sensorimotor link, we studied the attenuation (gating) of somatosensory evoked potentials (SEPs) before and during hand movements in patients with writer's cramp. For premovement gating, 10 patients and 11 age-matched normal subjects were given a warning sound followed 1s later by an electric stimulus to the right median nerve at the wrist. The latter served both as a reaction signal to start a finger extension task and as the input to evoke SEPs over the scalp. Because reaction times always exceeded 70 ms, short-latency SEPs thus obtained were unaffected by the afferents activated by the movement. The amplitudes of frontal N30 components were significantly decreased over the frontal leads compared with SEPs elicited at rest (P: < 0.002) in the normal group, whereas significant gating was found not for N30 but for frontal P22 (P: = 0. 002) in the patient group. For midmovement gating studies, SEPs to the right median nerve stimulation were recorded in 16 patients and 12 age-matched normal subjects at rest, and during active and passive finger extension-flexion movements. In contrast to the premovement SEPs, the frontal N30 was equally gated during active and passive movements both in the patient (P: < or = 0.002) and the normal group (P: < or = 0.003). These findings indicate that in writer's cramp the sensitivity of sensory input channels from the hand is wrongly set by the central command to move. Perhaps the sensory trick, by supplying additional input not usually present during unobstructed movement, is a manoeuvre to correct this imbalance. Dystonia may result not only from abnormalities in the central motor command but also from disturbed central processing of sensory input.

Activity-dependent conduction block in multifocal motor neuropathy

Patients with multifocal motor neuropathy may complain of muscle fatigue, even though the degree of conduction block assessed at rest has improved with treatment. To explore the mechanism involved, we examined changes in muscle force during maximum voluntary contraction (MVC) and monitored conduction block before and after MVC in five patients with multifocal motor neuropathy. The results were compared with those for the contralateral unaffected homonymous muscles. For one patient, who had bilateral involvement, a normal subject of a similar age and stature served as the control. Results of conduction studies were also compared with those from six patients with amyotrophic lateral sclerosis (ALS) with similar compound muscle action potential (CMAP) amplitudes after proximal stimulation. During MVC for 60 s, the affected muscles developed prominent fatigue; the force at the end of contraction compared with the initial force was significantly lower for the affected muscles [42 +/- 19% (mean +/- standard deviation) of the initial force] than for the control muscles (94 +/- 9%; P = 0.01). After MVC, the amplitude ratio of CMAPs after proximal versus distal nerve stimulation transiently decreased to 19 +/- 14% of that before MVC in the affected muscles, but not in the control muscles (94 +/- 3.8% of that before MVC) and in patients with ALS (95 +/- 6.7%). In one patient with a focal lesion in the forearm, nerve excitability was monitored at the lesion site before and after MVC for 120 s. There were significant increases in axonal threshold (approximately 48%) and supernormality (approximately 135%) immediately after MVC, suggesting that the axonal membrane had undergone hyperpolarization and, by extrapolation, that this had precipitated the conduction block. This study is the first to show that activity-dependent conduction block plays a role in human disease by causing muscle fatigue.

Adenovirus-mediated gene therapy to liver grafts: successful gene transfer by donor pretreatment

BACKGROUND

We have previously shown excellent adenoviral (Ad) gene transfection to transplanted liver grafts with the clamp technique (CT) where viral vector was delivered ex vivo and trapped in cold preserved liver grafts. In this study, we adopted a new gene therapy approach to achieve early transgene expression by donor pretreatment with viral vector and compared the efficacy of these two methods by using Ad vector encoding enhanced green fluorescent protein (AdEGFP) marker gene.

METHODS

AdEGFP (1 x 10(9)plaque forming units) was delivered to the liver grafts by: (1) single intravenous injection to donor Lewis rats 48 hours before harvesting, (2) ex vivo cold infusion into the harvested liver with CT, or (3) a combination of both methods. Liver grafts were stored in University of Wisconsin solution at 4 degrees C for 18 hours and then orthotopically transplanted into syngeneic recipients, and the expression of EGFP was studied.

RESULTS

With intravenous pretreatment of donor liver grafts, EGFP-expressing cells were detected as early as 3 hours after transplant, and moderate expression was seen by 12 hours. In contrast, EGFP was not detected until 12 to 24 hours after transplant with CT. High levels of EGFP-producing cells were seen with each technique at 7 days ( approximately 30% transfection efficiency). A combination of both methods did not enhance infectivity. Liver preservation injury was comparable between groups.

CONCLUSIONS

Gene transfer by donor pretreatment with AdEGFP induces early and efficient gene transduction to liver grafts compared with back-table delivery with CT. This method is simple and provides early transgene expression in liver grafts that potentially could be used to deliver genes to decrease preservation injury or rejection.

Concanavalin A simultaneously primes liver hematopoietic and epithelial progenitor cells for parallel expansion during liver regeneration after partial hepatectomy in mice

Liver hematopoietic progenitor cells (LHPC) and liver epithelial progenitor cells (LEPC) share a remarkable number of growth and differentiation-controlling receptor-ligand signaling systems. These likely account for the ability of the liver to support hematopoiesis in fetal life, and possibly for suggestions that LHPC can differentiate into hepatocytes. In these experiments, the kinetics and magnitude of LHPC and LEPC activation and expansion were studied by using a concanavalin A (Con A) liver injury model followed by partial hepatectomy (PH). Studies were performed in interleukin 6-deficient (IL-6(-/-)) mice and wild-type (IL-6(+/+)) controls, which show equal susceptibility to Con A- induced injury, because IL-6/gp130 signaling has been implicated in both LHPC and LEPC expansion. Con A pretreatment primed LHPC and LEPC for a rapid and parallel expansion after PH in IL-6(+/+) mice, which was significantly blunted and delayed in the IL-6(-/-) mice. Exogenous IL-6 given immediately before PH after Con A, augmented both LHPC and LEPC expansion in the IL-6(-/-) mice. Thus, the proinflammatory cytokine IL-6, commonly produced in liver injury and inflammatory disease, is an important growth factor involved in the expansion of LHPC and LEPC. This observation has implications for both hepatic carcinogenesis and transplantation.

Growth control of human biliary epithelial cells by interleukin 6, hepatocyte growth factor, transforming growth factor beta1, and activin A: comparison of a cholangiocarcinoma cell line with primary cultures of non-neoplastic biliary epithelial cells

A well characterized human cholangiocarcinoma (CC) cell line, SG231, was compared with primary cultures of normal human biliary epithelial cells (BECs) for alterations in interleukin 6 (IL-6) and hepatocyte growth factor (HGF)-mediated stimulation and transforming growth factor beta1 (TGF-beta1) and activin A-mediated inhibition of growth. Results were compared with immunolabeling of the original tumor and after injection of SG231 into the liver of BALB/cByJ-scid mice. In vitro, both BECs and CCs expressed met, gp80, and gp130 messenger RNA (mRNA) and protein, but the levels of expression were higher in the CCs than in the BECs. In both the CCs and BECs, exogenous HGF or IL-6 induced phosphorylation of met or gp130, respectively, and a concentration-dependent increase in DNA synthesis. However, the CCs but not BECs, continued to grow in basal serum-free medium (SFM) and spontaneously produced both IL-6 and HGF under these conditions, which resulted in auto-phosphorylation of gp130 and met, respectively; and neutralizing anti-HGF or anti-IL-6 alone inhibited CC growth, indicative of autocrine growth control circuits. Conversely, activin A inhibits the growth of both BECs and CCs, but does not significantly increase apoptosis. Activin-A-induced growth inhibition of both CCs and BECs can be reversed by 100 ng/mL exogenous IL-6, but not by 10 to 100 ng/mL HGF. TGF-beta1 inhibited the growth of BECs but had no mitoinhibitory or proapoptotic effects on CCs. Immunolabeling of the original tumor and after inoculation into scid mice showed positive staining for met, gp130, gp80, and IL-6. This study contributes to a further understanding of BEC growth control and derangements that can occur during cholangiocarcinogenesis.

Chronic liver allograft rejection in a population treated primarily with tacrolimus as baseline immunosuppression: long-term follow-up and evaluation of features for histopathological staging

BACKGROUND

Predisposing factors, long-term occurrence, and histopathological changes associated with recovery or progression to allograft failure from chronic rejection (CR) were studied in adult patients treated primarily with tacrolimus.

METHODS

CR cases were identified using stringent criteria applied to a retrospective review of computerized clinicopathological data and slides.

RESULTS

After 1973 days median follow-up, 35 (3.3%) of 1049 primary liver allograft recipients first developed CR between 16 and 2532 (median 242) days. The most significant risk factors for CR were the number (P<0.001) and histological severity (P<0.005) of acute rejection episodes and donor age >40 years (P<0.03). Other demographic and matching parameters were not associated with CR in this cohort. Ten patients died with, but not of, CR. Eight required retransplantation because of CR at a median of 268 days. Ten resolved either histologically or by normalization of liver injury tests over a median of 548 days. CR persisted for 340 to 2116 days in the remaining seven patients. More extensive bile duct loss (P<0.01), smallarterial loss (P<0.03), foam cell clusters (P<0.01) and higher total bilirubin (P<0.02) and aspartate aminotransferase (P<0.03) were associated with allograft failure from CR.

CONCLUSIONS

Early chronic liver allograft rejection is potentially reversible and a combination of histological, clinical, and laboratory data can be used to stage CR. Unique immunological and regenerative properties of liver allografts, which lead to a low incidence and reversibility of early CR, can provide insights into transplantation biology.

The effect of interleukin-6 (IL-6)/gp130 signalling on biliary epithelial cell growth, in vitro

The effect of IL-6 on the growth of mouse biliary epithelial cells (BEC), in vitro, was tested by comparing BEC obtained IL-6-deficient mice (IL-6(-/-)) to wild-type littermate controls (IL-6(+/+)), in two different media: simple serum-free media (S-SFM), and complete serum-free media (C-SFM) containing forskolin, which stimulates BEC IL-6 production. In S-SFM, neither IL-6(+/+)nor IL-6(-/-)BEC constitutively produced IL-6 mRNA or protein, and there was no difference between IL-6(+/+)and IL-6(-/-)BEC growth. In contrast, when the BEC were maintained in C-SFM, over 48 h, the growth of IL-6(+/+)BEC was 40% greater than IL-6(-/-)BEC (P<0.006). Enhanced IL-6(+/+)BEC growth in C-SFM was associated with induced expression of IL-6 mRNA and IL-6 protein secretion into the medium, upregulation of the IL-6Ralpha (gp80) and phosphorylation of the signal transducing molecule gp130. In C-SFM, anti-IL-6 neutralizing antibodies blocked enhanced IL-6(+/+)BEC growth, whereas exogenous rhIL-6 stimulated retarded growth of IL-6(-/-)BEC. Thus, under conditions that mimic an inflammatory or stressful microenvironment in vivo, BEC produce, secrete and respond to IL-6, via upregulation and activation of the IL-6Ralpha (gp80)/gp130 signaling system in an autocrine/paracrine manner.

Vitamin E level changes in serum and red blood cells due to acute exhaustive exercise in collegiate women

The purpose of this study was to investigate the change in vitamin E level in both serum and red blood cells (RBC) during exercise and to clarify the effect of vitamin E supplementation. Ten young sedentary female subjects received 200 mg D-alpha-tocopherol acetate daily for 1 wk after the initial exercise bout. After 1 wk of vitamin E supplementation, the same subjects repeated the same exercise. Before vitamin E supplementation, the alpha-tocopherol level in the serum (serum-alpha-tocopherol) did not change after exercise, but a significant decrease in the alpha-tocopherol level in RBC (RBC-alpha-tocopherol) was observed after exercise (p < 0.05). On the other hand, after vitamin E supplementation, the serum-alpha-tocopherol level decreased significantly after exercise (p < 0.05), while the RBC-alpha-tocopherol level was maintained after exercise. Furthermore, a negative correlation between the changes in serum- and RBC-alpha-tocopherol levels was observed only after vitamin E supplementation (r = 0.667, p < 0.05). The present results suggest that as RBC suffers oxidative stress, vitamin E in RBC is consumed to protect RBC from oxidative damage during exercise. These results also suggest that when there is a sufficient amount of vitamin E in the serum, vitamin E is shifted from the serum to RBC, resulting in a steady RBC-alpha-tocopherol level and a decrease in the serum-alpha-tocopherol level under oxidative stress such as exercise.

The development and compensation of biliary cirrhosis in interleukin-6-deficient mice

In an effort to understand the role of IL-6/gp130 signaling in chronic liver injury, IL-6 deficient (IL-6(-/-)) and wild-type control (IL-6(+/+)) mice were subjected to bile duct ligation (BDL) for 12 weeks. This maneuver causes chronic biomechanical stress and liver injury, fueling sustained biliary epithelial and hepatocyte proliferation. By 12 weeks after BDL, IL-6(-/-) mice develop significantly higher total serum bilirubin levels (23.2 +/- 2.3 versus 14.9 +/- 2.1 mg/dl, P < 0.0001; delta bilirubin subfraction 16.7 +/- 4.0% versus 9.2 +/- 1.8%; P < 0.002), and the majority (15/18) show "black" gallbladder bile, compared to IL-6(+/+) mice (5/16; P < 0.003). The IL-6(-/-) mice also cannot sustain the compensatory liver mass increase commonly seen with chronic obstructive cholangiopathy, because of less hepatocyte proliferation, despite a rate of hepatocyte apoptosis similar to that of IL-6(+/+) mice. Moreover, IL-6(-/-) mice show a more advanced stage of biliary fibrosis and a higher mortality rate than the IL-6(+/+) controls (51% versus 23%; P < 0.02). These phenotypic changes in the IL-6(-/-) mice are associated with decreased expression and phosphorylation of gp130 and the transcription factor STAT3, compared to IL-6(+/+) mice. Daily treatment with exogenous recombinant IL-6 for 3-6 weeks starting at 6 weeks after BDL significantly lowers the serum total bilirubin in both groups. In the IL-6(-/-) mice, exogenous IL-6 treatment also increases the level of gp130 protein expression and completely reverses the loss of liver mass by increasing the hepatocyte proliferation. In conclusion, IL-6 appears to contribute to biliary tree integrity and maintenance of hepatocyte mass during chronic injury.

The relationship between physical fitness and coronary risk factor profiles in Japanese women

The purpose of this study was to investigate the relationship between physical fitness and coronary risk factor profiles in Japanese women. The subjects were 1,483 women (ages 30 to 69) who participated in a practical health promotion program. After medical examination, physical fitness was evaluated by conducting a symptom limited maximal exercise test by ergometer to measure maximum oxygen uptake (peakVO(2)) with an expired gas analyzer. The subjects were classified into 3 groups (high fitness, moderate fitness, and low fitness) according to age and physical fitness level. The results showed that the subjects in higher fitness groups had lower levels in: body mass index (BMI), percentage of body fat, waist-hip ratio, resting blood pressure, and atherogenic index, and higher HDL-cholesterol compared to those in lower fitness group. Even after adjustment for the effects of age and BMI, die subjects in the higher fitness groups had better coronary risk factor profiles. These results suggest that among Japanese women a high level of physical fitness is related to favorable coronary risk factor profiles.

Acute obstructive cholangiopathy in interleukin-6 deficient mice: compensation by leukemia inhibitory factor (LIF) suggests importance of gp-130 signaling in the ductular reaction

AIM

The hypothesis that interleukin-6-IL-6/gp130 signaling is involved in liver and biliary epithelial cell (BEC) biology and growth control was tested by subjecting homozygous IL-6 deficient mice (IL-6-/-) and wild type (IL-6+/+) littermate controls to bile duct ligation (BDL).

MATERIALS AND METHODS

During the first week after BDL, the two groups were compared with respect to routine liver injury tests, liver histology, BEC and hepatocyte DNA synthesis, together with the expression of mRNA and protein of IL-6 as well as related growth factors, and their receptors.

RESULTS

During the first week after BDL, there was marked upregulation of IL-6 mRNA and protein in the IL-6+/+ mice only in the vicinity of the biliary tree; whereas, biliary/peri-biliary IL-6R, HGF and met mRNA and protein increased in both groups. IL-6, HGF mRNA and protein localized to periductal inflammatory cells and stellate cells, while met and IL-6R protein were upregulated in the BEC and, to a lesser extent, in hepatocytes. This occurred during maximal proliferation of the BEC. Despite the absence of IL-6 in the IL-6-/- mice, there were only mildly phenotypic differences between the two groups, and no differences in mortality. Compared to IL-6+/+ controls, IL-6-/- mice showed slightly less BEC proliferation, a trend toward more liver injury, and significantly higher total serum bilirubin (TB) levels, suggestive of impaired biliary tree integrity. These changes were associated with slightly less HGF mRNA and protein expression in the IL-6-/- mice, but the differences were not significant. Leukemia inhibitory factor (LIF), another gp-130 ligand, also showed marked peri-biliary upregulation after BDL in both groups, and also induced BEC DNA synthesis, in vitro.

CONCLUSIONS

The mild phenotypical differences between IL-6+/+ and IL-6-/- mice in the acute response to BDL is most likely attributable to the redundancy of the gp-130 signaling system. However, the long-term response to BDL results in a distinct phenotype in the IL-6-/- mice, marked by a relentless rise in serum total bilirubin and an inability to maintain compensatory increase in liver mass.

Quantification of ischemic muscle deoxygenation by near infrared time-resolved spectroscopy

The purpose of this study was to quantify muscle deoxygenation in human skeletal muscles using near infrared time-resolved spectroscopy (NIRTRS) and compare NIRTRS indicators and blood saturation. The forearm muscles of five healthy males (aged 27-32 yrs.) were monitored for changes in hemoglobin saturation (SO2) during 12 min of arterial occlusion and recovery. SO2 was determined by measuring the temporal profile of photon diffusion at 780 and 830 nm using NIRTRS, and was defined as SO2-TRS. Venous blood samples were also obtained for measurements of SvO2, and PvO2. Interstitial PO2(PintO2) was monitored by placing an O2 electrode directly into the muscle tissue. Upon the initiation of occlusion, all parameters fell progressively until reaching a plateau in the latter half of occlusion. It was observed at the end of occlusion that SO2-TRS (24.1 +/- 5.6%) agreed with SvO2 (26.2 +/- 6.4) and that PintO2 (14.7 +/- 1.0 Torr) agreed with PvO2 (17.3 +/- 2.2 Torr). The resting O2 store (oxygenated hemoglobin) and O2 consumption rate were 290 microM and 0.82 microM s-1, respectively, values which reasonably agree with the reported results. These results indicate that there was no O2 gradient between vessels and interstisium at the end of occlusion.

EXTL3/EXTR1 alterations in colorectal cancer cell lines

We previously demonstrated that metastasis-related tumor suppressor gene(s) may exist on chromosome 8p21-22 on allelotype analysis of early colorectal carcinomas (CRC) with lymph node metastasis. Here, we searched for target gene(s) in this chromosomal region in the UniGene database. The EXTL3 (also called EXTR1) gene was selected as a candidate because of its homology to EXT1 and EXT2, putative tumor suppressor genes. We screened 12 CRC cell lines for mutations by means of polymerase chain reaction (PCR)-single strand conformation polymorphism. Three cell lines showed EXTL3 mutations, all of which were located within exon 3 and caused amino acid substitutions. Reverse transcription-PCR analysis showed that the EXTL3 expression was lacking in 1 of the 12 colorectal cancer cell lines. Although there is still no definitive evidence that EXTL3 is a tumor suppressor gene for CRC, these data suggest that inactivation of the EXTL3 gene may at least offer a selective growth advantage for some CRC cell lines.

[Complete responses in patients with unresectable liver metastases from colorectal cancer with weekly high-dose 5-FU plus one-shot CDDP HAI]

Thirty-two patients with unresectable liver metastases from colorectal cancer, treated by intermittent hepatic arterial infusion of high-dose 5-FU combined with CDDP, were assessed. As a result of this treatment, the overall response rate was 65.6%, and eight patients (25%) which contained three autopsy cases revealed a complete response. The mean doses of 5-FU and CDDP which was administered in the eight patients were 24.3 g and 65 mg, respectively. One of the eight patients showed complete disappearance of liver metastasis on the CT scan after arterial infusion of 4.5 g of 5-FU, and necrosis or disappearance of the tumor was present in more than 2/3 of the whole lesion. Autopsy showed focal or zonal necrosis, distorted reconstruction of architecture, and cholangiolitis of the liver which were administered more than 15 g of 5-FU. Intermittent hepatic arterial infusion of high-dose 5-FU combined with CDDP is proved to be a useful locoregional chemotherapy for liver metastasis from colorectal cancer. We should evolve new treatment modalities for extrahepatic metastases, as HAI combined with the systemic chemotherapeutic regimen.

[Complications related to hepatic arterial infusion chemotherapy for liver metastasis from colorectal cancer]

We evaluated the complications of hepatic arterial infusion (HAI) chemotherapy in patients (pts) with hepatic metastasis from colorectal cancer. The subjects consisted of 61 pts with hepatic metastasis from colorectal cancer, who were treated by combined chemotherapy with 5-FU and CDDP weekly or continuously. Indwelling route of catheter: 30 via gastroduodenal artery (GDA) at the time of laparotomy ('LP'), 21 via femoral artery (FA) and catheter tip in PHA ('PHA'), 10 via FA and catheter tip is inserted with steel coil into the GDA ('GDA-coil'). Complications resulting in interruption of therapy occurred in 19 pts (31%), and the 'GDA-coil' method had a lower rate of complication than others. There was no difference in the incidence rate of complications between the two chemotherapy regimens. The complications of this therapy were: 8 (13%) cases of hepatic arterial occlusion, 3 (5%) cases of duodenal ulcer, 4 (7%) cases of catheter tip dislocation, 2 (3%) cases of catheter tip dislocation to the duodenal bulb, and 1 (2%) case of liver abscess. Hepatic arterial occlusion occurred frequently in LP. Up to 67% of patients with duodenal ulcer had hepatic arterial occlusion at the same time. All pts with catheter tip dislocation were 'PHA', and all pts with catheter tip dislocation to the duodenal bulb were 'LP'.

IN CONCLUSION

1. The best indwelling route for the catheter is by the 'GDA-coil' method. 2. To diagnose complications soon, regular CTA or DSA is necessary.

Pre-movement gating of short-latency somatosensory evoked potentials

Somatosensory evoked potentials (SEPs) are reduced in amplitude during movement (gating). The mechanism involves central gating of afferent input and competition from other afferents activated by the movement. We distinguished these two by giving 11 normal subjects a warning sound followed 1 s later by an electric stimulus to the right median nerve at the wrist. The latter served both as a cue to start a finger movement and as stimulation to evoke SEPs. Gating effects were widespread in frontal (N30) and central (N60) areas, but were also seen, albeit to a lesser extent, in the recordings at P3 (P30). Since finger movement began after the stimulus, such gating must have been purely central in origin, presumably reflecting motor preparation.

Dendritic cells/chimerism/alleviation of chronic allograft rejection

Chronic rejection (CR) is the major obstacle of long-term successful organ transplantation. Using a recently developed rat model of CR, we found that heart allografts susceptible to development of CR showed an early (< 10 days) dramatic disappearance of donor MHC class II+ cells, including ED2+ tissue macrophages, and an influx of recipient ED1+ macrophages intermixed with small numbers of recipient ED2+ and OX62+ cells. In contrast, donor MHC class II+ cells persisted in allografts resistant to CR with a small influx of recipient macrophages. MHC class II+ cells function as potent modulators of the immune system and may mediate both stimulatory and tolerogenic immune reactions after transplantation. Persistence of donor MHC class II+ antigen-presenting cells (APC) in CR-free graft acceptance suggests that transplantation tolerance is an active immune response requiring antigen presentation to the recipient immune system in the proper context by dendritic cells and other APC.

Bone marrow as a potential source of hepatic oval cells

Bone marrow stem cells develop into hematopoietic and mesenchymal lineages but have not been known to participate in production of hepatocytes, biliary cells, or oval cells during liver regeneration. Cross-sex or cross-strain bone marrow and whole liver transplantation were used to trace the origin of the repopulating liver cells. Transplanted rats were treated with 2-acetylaminofluorene, to block hepatocyte proliferation, and then hepatic injury, to induce oval cell proliferation. Markers for Y chromosome, dipeptidyl peptidase IV enzyme, and L21-6 antigen were used to identify liver cells of bone marrow origin. From these cells, a proportion of the regenerated hepatic cells were shown to be donor-derived. Thus, a stem cell associated with the bone marrow has epithelial cell lineage capability.

A fresh look at augmenter of liver regeneration in rats

Augmenter of liver regeneration (ALR) is a hepatotrophic protein originally identified by bioassay in regenerating rat and canine livers following partial hepatectomy and in the hyperplastic livers of weanling rats, but not in resting adult livers. The ALR gene and gene product were subsequently described, but little is known about the cellular/subcellular sites of ALR synthesis in the liver, or about the release and dissemination of the peptide. To obtain this information in rats, we raised antibodies in rabbits against rat ALR for development of an enzyme-linked immunosorbent assay (ELISA). ALR concentrations were then determined in intact livers of unaltered weanling and adult rats; in regenerating residual liver after partial hepatectomy; in cultured hepatocytes and nonparenchymal cells (NPCs); and in culture medium and serum. ALR in the various liver cells was localized with immunohistochemistry. In addition, hepatic ALR and ALR mRNA were assayed with Western blotting and reverse-transcriptase polymerase chain reaction (RT-PCR), respectively. The hepatocyte was the predominant liver cell in which ALR was synthesized and stored; the cultured hepatocytes secreted ALR into the medium in a time-dependent fashion. Contrary to previous belief, the ALR peptide and ALR mRNA were present in comparable concentrations in the hepatocytes of both weanling and resting adult livers, as well as in cultured hepatocytes. A further unexpected finding was that hepatic ALR levels decreased for 12 hours after 70% hepatectomy in adult rats and then rose with no corresponding change in mRNA transcripts. In the meantime, circulating (serum) ALR levels increased up to 12 hours and declined thereafter. Thus, ALR appears to be constitutively expressed in hepatocytes in an inactive form, and released from the cells in an active form by unknown means in response to partial hepatectomy and under other circumstances of liver maturation (as in weanling rats) or regeneration.

Donor hematopoietic progenitor cells in nonmyeloablated rat recipients of allogeneic bone marrow and liver grafts

BACKGROUND

Although the persistence of multilineage microchimerism in recipients of long-surviving organ transplants implies engraftment of migratory pluripotent donor stem cells, the ultimate localization in the recipient of these cells has not been determined in any species.

METHODS

Progenitor cells were demonstrated in the bone marrow and nonparenchymal liver cells of naive rats and in Brown Norway (BN) recipients of Lewis (LEW) allografts by semiquantitative colony-forming unit in culture (CFU-C) assays. The LEW allografts of bone marrow cells (BMC) (2.5x10(8)), orthotopic livers, or heterotopic hearts (abdominal site) were transplanted under a 2-week course of daily tacrolimus, with additional single doses on days 20 and 27. Donor CFU-C colonies were distinguished from recipient colonies in the allografts and recipient bone marrow with a donor-specific MHC class II monoclonal antibody. The proportions of donor and recipient colonies were estimated from a standard curve created by LEW and BN bone marrow mixtures of known concentrations.

RESULTS

After the BMC infusions, 5-10% of the CFU-C in the bone marrow of BN recipients were of the LEW phenotype at 14, 30, and 60 days after transplantation. At 100 days, however, donor CFU-C could no longer be found at this site. The pattern of LEW CFU-C in the bone marrow of BN liver recipients up to 60 days was similar to that in recipients of 2.5x10(8) BMC, although the donor colonies were only 1/20 to 1/200 as numerous. This was expected, because the progenitor cells in the passenger leukocytes of a single liver are equivalent to those in 1-5x10(6) BMC. Using a liquid CFU-C assay, donor progenitor cells were demonstrated among the nonparenchymal cells of liver allografts up to 100 days. In contrast, after heart transplantation, donor CFU-C could not be identified in the recipient bone marrow, even at 14 days.

CONCLUSION

effective immunosuppression, allogeneic hematopoietic progenitors compete effectively with host cells for initial engraftment in the bone marrow of noncytoablated recipients, but disappear from this location between 60 and 100 days after transplantation, coincident with the shift of donor leukocyte chimerism from the lymphoid to the nonlymphoid compartment that we previously have observed in this model. It is possible that the syngeneic parenchymal environment of the liver allografts constitutes a privileged site for persistent progenitor donor cells.

Chimerism and xenotransplantation. New concepts

In both transplant and infectious circumstances, the immune response is governed by migration and localization of the antigen. If the antigenic epitopes of transgenic xenografts are sufficiently altered to avoid evoking the destructive force of innate immunity, the mechanisms of engraftment should be the same as those that permit the chimerism-dependent immunologic confrontation and resolution that is the basis of allograft acceptance. In addition to "humanizing" the epitopes, one of the unanswered questions is whether the species restriction of complement described in 1994 by Valdivia and colleagues also necessitates the introduction of human complement regulatory genes in animal donors. Because the liver is the principal or sole source of most complement components, the complement quickly is transformed to that of the donor after hepatic transplantation. Thus, the need for complementary regulatory transgenes may vary according to the kind of xenograft used. Much evidence shows that physiologically important peptides produced by xenografts (e.g., insulin, clotting factors, and enzymes) are incorporated into the metabolic machinery of the recipient body. To the extent that this is not true, xenotransplantation could result in the production of diseases that are analogous to inborn errors of metabolism. In the climate of pessimism that followed the failures of baboon to human liver xenotransplantation in 1992-1993, it seemed inconceivable that the use of even more discordant donors, such as the pig, could ever be seriously entertained; however, this preceded insight into the xenogeneic and allogeneic barriers that has brought transplantation infectious immunity to common ground. With this new insight and the increasing ease of producing transgenic donors, the goal of clinical xenotransplantation may not be so distant.

Mitosis and apoptosis in the liver of interleukin-6-deficient mice after partial hepatectomy

Recently, it was shown that hepatocyte DNA synthesis after partial hepatectomy (PH) is impaired in interleukin-6-deficient (IL-6(-/-)) mice, which results in significantly delayed, but eventual, recovery of normal liver weight, compared with the IL-6(+/+) controls. Four possible compensatory mechanisms might explain this phenomenon: 1) hepatocyte hypertrophy; 2) activation of the oval cell compartment and subsequent maturation to hepatocytes; 3) non-oval biliary epithelial cell (BEC) proliferation; and/or 4) differential rates of apoptotic cell death in the regenerating liver. These hypotheses were tested by subjecting IL-6(-/-) and IL-6(+/+) mice to PH and determining sequential liver weight, histology, hepatocyte and BEC 5'-bromo-2'-deoxyuridine (BrdU) labeling, liver DNA content, alpha-fetoprotein (AFP) mRNA production, and apoptosis at several time points after PH. Consistent with previous studies, we show that the absence of IL-6 significantly impairs hepatocyte DNA synthesis and delays liver weight recovery after PH, but the defect observed in this study is less severe than that previously reported, and no excess mortality, massive necrosis on histology, nor differences in liver injury test are seen. Interestingly, the IL-6(-/-) mice show more hepatocyte BrdU pulse labeling than the IL-6(+/+) controls at 24 hours, but less at 36, 48, and 60 hours. Continuous BrdU infusion up to 60 hours after PH showed a cumulative hepatocyte labeling index of 79.5% in IL-6(+/+) mice and 70.8% in IL-6(-/-) mice, respectively (P <.03). However, despite a lower labeling index and significantly delayed weight recovery, hepatic mass was equally restored in the two groups by 96 hours. There was no evidence of oval cell proliferation in the IL-6(-/-) mice, as determined by routine histology and AFP mRNA analysis, and non-oval BEC proliferation was also slightly impaired in the IL-6(-/-) mice compared with the IL-6(+/+) mice. In addition, liver DNA content per gram of liver showed an increase compared with normal at 60 hours in both groups, but by 96 hours, there was no difference between the two groups. Thus, neither oval cell nor BEC proliferation, nor hepatocyte hypertrophy, could account for the eventual equivalent weight recovery. There was, however, a difference between the two groups in the rate of apoptosis. In normal livers of both IL-6(-/-) and IL-6(+/+) mice, apoptotic cells were uncommon, and even fewer such cells were detected at 24, 36, and 48 hours after PH. Between 60 and 96 hours after PH, a wave of apoptosis spread through the livers of both groups. The number of apoptotic cells was directly proportional to the magnitude of hepatocyte BrdU labeling and liver DNA content after PH, and the difference between the nadir of apoptosis at 24 hours and the peak at 96 hours was greater for the IL-6(+/+) mice. In addition, a direct comparison between the two groups at 96 hours showed that hepatocyte apoptosis was significantly lower in the IL-6(-/-) versus the IL-6(+/+) mice (P <. 02). Treatment of the IL-6(-/-) mice with rIL-6 completely reversed the hepatocyte proliferation defect and increased the subsequent level of total apoptotic bodies. The fine control of liver weight recovery during regeneration after PH is a complex process that involves both mitosis and apoptosis. IL-6 affects this process by recruiting, and possibly synchronizing, the entry of hepatocytes into cell cycling, which quickly restores liver mass. However, this robust response generates superfluous hepatocytes, which are eliminated via apoptosis, similar to many other processes involving organ growth.

Reduced blood flow in abdominal viscera measured by Doppler ultrasound during one-legged knee extension

The redistribution of blood flow (BF) in the abdominal viscera during right-legged knee extension-flexion exercise at very low intensity [peak heart rate (HR), 76 beats/min] was examined by using Doppler ultrasound. While sitting, subjects performed a right-legged knee extension-flexion exercise every 6 s for 20 min. BF was measured in the upper abdominal aorta (Ao), right common femoral artery (RCFA), and left common femoral artery (LCFA). Visceral BF (BFVis) was determined by the equation [BFAo - (BFRCFA + BFLCFA)]. A comparison with the change in BF (DeltaBF) preexercise showed a greater increase in DeltaBFRCFA than in DeltaBFAo during exercise. This resulted in a reduction of BFVis to 56% of its preexercise value or a decrease in flow by 1,147 +/- 293 (+/-SE) ml/min at the peak workload. Oxygen consumption correlated positively with DeltaBFAo, DeltaBFRCFA, and DeltaBFLCFA but inversely with DeltaBFVis during exercise and recovery. Furthermore, BFVis (% of preexercise value) correlated inversely with both an increase in HR (r = -0.89), and percent peak oxygen consumption (r = -0.99). This study demonstrated that, even during very-low-intensity exercise (HR <90 beats/min), there was a significant shift in BF from the viscera to the exercising muscles.