Liver allograft pathology in liver/small bowel or multivisceral recipients

Combined liver/small bowel (LSB) and multivisceral (MV) transplantation represents an alternative treatment for patients with short-gut syndrome complicated by end-stage liver disease. However, the question of whether the addition of an intestinal allograft alters the pathologic features of the transplanted liver remains unanswered. We, therefore, evaluated the histologic features of 51 liver biopsy specimens from 13 LSB or MV recipients and compared them with a matched control group of specimens from recipients of isolated liver allografts. In general, the histologic alterations were comparable in the LSB/MV and control groups. The primary difference was that portal and sinusoidal neutrophilia accompanied acute cellular rejection in 10 (63%) of 16 LSB/MV specimens but none of the control specimens. Concurrent culture results were positive in 5 of the 10 cases: bacterial overgrowth of the intestinal allograft was found in 3 cases, and bacteremia in 2 other cases, 1 of which had also a positive liver culture. In contrast, these cultures (n = 7) were negative in the six LSB/MV cases of neutrophil-free acute cellular rejection. Neutrophilia was also present in 26 additional LSB/MV specimens, including instances of preservation injury, sepsis, impaired bile flow due to ampullary dysfunction, and one case without an underlying diagnosis, but its frequency did not significantly differ from that of corresponding control cases. An additional finding was the occurrence of a "fibrosing cholestatic" pattern of acquired hepatitis C in 10 specimens from 2 LSB/MV recipients. Acute cellular reaction-associated neutrophilia in LSB/MV recipients may reflect portal bacteremia resulting from bacterial overgrowth and translocation from the intestinal graft or represent simply a nonspecific hepatic response to intestinal inflammatory processes.

Adaptive Management: Promises and Pitfalls

Proponents of the scientific adaptive management approach argue that it increases knowledge acquisition rates, enhances information flow among policy actors, and provides opportunities for creating shared understandings. However, evidence from efforts to implement the approach in New Brunswick, British Columbia, Canada, and the Columbia River Basin indicates that these promises have not been met. The data show that scientific adaptive management relies excessively on the use of linear systems models, discounts nonscientific forms of knowledge, and pays inadequate attention to policy processes that promote the development of shared understandings among diverse stakeholders. To be effective, new adaptive management efforts will need to incorporate knowledge from multiple sources, make use of multiple systems models, and support new forms of cooperation among stakeholders.

Pathology of human intestinal transplantation

BACKGROUND & AIMS

Intestinal transplantation is a developing therapeutic option for patients with irreversible intestinal failure or short bowel syndrome. The aim of this study was to delineate the histopathology of human intestinal allografts and to define the features of intestinal rejection.

METHODS

The histological features of 3015 endoscopic biopsy specimens and 23 allograft specimens from 62 intestinal recipients were analyzed retrospectively and correlated with clinical findings.

RESULTS

Acute allograft rejection was characterized by a varying combination of crypt injury, mucosal infiltration primarily by mononuclear cells (including blastic lymphocytes), and increased crypt cell apoptosis (more than 2 per 10 crypts). It represented a patchy, often ileal-centered process that could progress to mucosal ulceration; later episodes (more than 100 days posttransplant) tended to show lesser cellular infiltration and greater apoptosis than earlier episodes. Correlation with clinical rejection was good (false-positive rate of 9%; false-negative rate of 26%). Two resected specimens showed obliterative arteriopathy indicative of chronic rejection. In other specimens, preservation injury, cytomegalovirus infection, post-transplant lymphoproliferative disorder, and nonspecific features of active or past mucosal injury could be recognized.

CONCLUSIONS

Mucosal biopsy specimens are a useful means of monitoring intestinal allografts. Based on features validated by clinical correlation, acute rejection can be identified reliably and can be differentiated from the other pathological processes affecting the intestinal allograft.

Impaired "natural reciprocal inhibition" in patients with spasticity due to incomplete spinal cord injury

Experiments were performed to compare the ability of normal subjects and patients with spinal spasticity to suppress antagonist H reflexes during isometric ankle contractions. Soleus H reflex suppression was examined during tonic pretibial muscle contractions in which the torque levels were constant and during dynamic pretibial muscle contractions in which the torque followed a predetermined ramp. As well, subjects were instructed to alternately contract ankle plantarflexors and dorsiflexors at various frequencies to examine patterns of EMG activity during rhythmically alternating isometric contractions in antagonist muscles. Patients with incomplete spinal cord injury demonstrated reduced ability to suppress soleus H reflexes during pretibial muscle contraction. At slow speeds of alternating contraction, spinal cord injured patients retained the ability to perform alternating isometric pretibial/soleus muscle contractions. The patients demonstrated abnormal coactivation in soleus muscle during faster alternating isometric ankle muscle contractions. Furthermore, the patients who demonstrated the greatest impairment in natural reciprocal inhibition, also displayed the largest amount of coactivation. In general, the results would suggest that impairment of natural reciprocal inhibition is correlated with an increase in the amount of antagonist muscle coactivation seen during alternating isometric muscle contractions.

Reciprocal inhibition in hemiplegia: correlation with clinical features and recovery

BACKGROUND

Previous reports have described changes in reciprocal Ia inhibition in hemiplegic patients, but correlations between the amount of Ia inhibition and the clinical deficits have not been well established.

METHODS

We studied reciprocal inhibition between ankle flexors (tibialis anterior) and extensors (soleus) in 16 hemiplegic patients at various stages following a stroke and in 26 control subjects. The amount of disynaptic Ia inhibition was determined from the short latency suppression of the soleus or tibialis anterior H-reflexes by conditioning stimulation of the antagonistic muscle nerves.

RESULTS

Disynaptic Ia inhibition from peroneal nerve afferents to soleus motoneurones was increased in patients who showed good recovery of function with mild spasticity. However, it was not changed, or even sometimes diminished, in patients who made a poor recovery and had more marked extensor spasticity. In patients where serial recordings were obtained there was an increase in Ia inhibition during the recovery period following stroke. Ia inhibition to the tibialis anterior motoneurones tended to be greater in the poor recovery patients with marked spasticity than in the good recovery patients. The late (D1) inhibition, presumably due to presynaptic inhibition, was decreased in the patients, although consistent correlations between the amount of this inhibition and the clinical features were not clearly demonstrated.

CONCLUSIONS

Changes in excitability of Ia inhibitory pathways can be correlated with some of the clinical features seen in hemiplegia. Increased Ia inhibition of soleus motoneurones during recovery may be a mechanism to compensate for loss of descending motor commands.

Persistence and fate of polychlorinated biphenyls (PCBs) in sewage sludge-amended agricultural soils

Four metal enriched sewage sludges containing different concentrations of polychlorinated biphenyls (PCBs) were applied to two field soils in the UK in 1968. Samples of the sludges, sludge-amended soils and soils from untreated control plots were stored and analysed retrospectively. Sludge concentrations ranged from 1 to 7 mg SigmaPCB kg(-1). The pattern of PCBs was similar in three of the four sludges, with congeners 14, 18, 28 and 52 present at the highest concentrations. The fourth sludge contained higher amounts of congeners 149, 153, 138 and 180. SigmaPCB concentrations in control plot soil have declined over the last 20 years, indicating a reduction in atmospheric deposition inputs of PCBs to the soil. SigmaPCB concentrations also declined on the sludge-amended plots, reaching control plot concentrations (30-60 microg SigmaPCB kg(-1)) in the late-1980s. Half-lives ranged from < 1 to 8.5 years for congeners 18, 28 and SigmaPCB. Biodegradation and/or the formation of reversibly sorbed soil PCB residues could not account for the losses observed. Volatilisation is implicated as the most important loss process on both the control and sludge-amended plots. Using the fugacity approach, congener concentrations in soils at Luddington were predicted still to have not reached equilibrium with the air. Further losses to the atmosphere are likely.

Mucosal perfusion and reactivity of the rat small intestinal allograft

During acute rejection (AR), the endothelial targeting seen in the mucosal vessels of the intestinal allograft (IA) could impair the blood supply and response to luminal stimuli. To study the effect of AR in the perfusion and reactivity of the IA mucosa, we measured the mucosal blood flow in the ileum (IL) of 2 groups of control rats (Lewis and ACI) and in the native and grafted IL of syngeneic (ACI to ACI) and allogeneic (donor ACI to recipient Lewis) rats. Using reflectance spectrophotometry and laser-Doppler flowmetry, parameters of mucosal oxygen saturation (ISO2), hemoglobin content (IHB), and blood flow (FLOW) were obtained at baseline and after saline and 50% dextrose (D50) stimulation. When compared to controls, the isograft IL had similar perfusion (ISO2, IHB, and FLOW). The allograft IL showed ischemia (similar ISO2, and lower ISO2 and FLOW). In the allografts, the ISO2 and FLOW were lower than in the isografts. In response to D50, the native IL of all groups showed an increased IHB and FLOW (hyperemia); the isografts showed an increase only in IHB (partial response); the allografts did not show any response at all. In summary, the mucosal perfusion in the rejecting allografts, but not in the isografts, showed ischemia. The response to D50 seen in the native ilea was only partial in the isografts and absent in the allografts. Because these changes occurred before the onset of mucosal ulcerations, we postulate that they could be used as early indicators of AR.

Mechanisms underlying functional recovery following stroke

This article reviews recent evidence from animal experiments indicating that there is considerable potential for reorganization of representations and functions in in sensory and motor cortex following localized lesions or various manipulations of peripheral target structures. Three major mechanisms for this plastic reorganization are considered: unmasking of existing but functionally inactive pathways, sprouting of fibers from surviving neurons and formation of new synapses, and redundancy of CNS circuitry allowing alternative pathways to take over functions. Studies using positron emission tomography or transcranial magnetic stimulation suggest that similar forms of neuroplasticity may occur in the human brain and could contribute to functional recovery following stroke. The potential therapeutic implications are discussed.

Outcome analysis of 71 clinical intestinal transplantations

OBJECTIVE

The aim of the study was to determine risk factors associated with graft failure and mortality after transplantation of the intestine alone or as part of an organ complex.

SUMMARY BACKGROUND DATA

Even with modern immunosuppressive therapies, clinical intestinal transplantation remains a difficult and unreliable procedure. Causes for this and solutions are needed.

METHODS

Between May 1990 and February 1995, 71 intestinal transplantations were performed in 66 patients using tacrolimus and low-dose steroids. The first 63 patients, all but one treated 1 to 5 years ago, received either isolated grafts (n = 22), liver and intestinal grafts (n = 30), or multivisceral grafts (n = 11). Three more recipients of allografts who recently underwent surgery and one undergoing retransplantation were given unaltered donor bone marrow cells perioperatively as a biologic adjuvant.

RESULTS

Of the first 63 recipients, 32 are alive: 28 have functioning primary grafts and 4 have resumed total parenteral nutrition after graft enterectomy. Thirty-five primary grafts were lost to technical and management errors (n = 10), rejection (n = 6), and infection (n = 19). Regression analysis revealed that duration of surgery, positive donor cytomegalovirus (CMV) serology, inclusion of graft colon, OKT3 use, steroid recycle, and high tacrolimus blood levels contributed to graft loss. All four intestine and bone marrow recipients are alive for 2-3 months without evidence of graft-versus-host disease.

CONCLUSION

To improve outcome after intestinal transplantation with previous management protocols, it will be necessary to avoid predictably difficult patients, CMV seropositive donors, and inclusion of the graft colon. Bone marrow transplantation may further improve outcome by ameliorating the biologic barriers of rejection and infection and allowing less restrictive selection criteria.

Preparatory postural adjustments in parkinsonian patients with postural instability

BACKGROUND

Postural instability is a common problem in patients with Parkinson's disease. This paper reports results of a study undertaken to investigate some of the possible mechanisms responsible for this instability.

METHODS

Preparatory postural adjustments associated with a lateral leg raising task were studied in five parkinsonian patients and four age-matched controls. Recordings included ground reaction forces, kinematics, and surface EMG activity from multiple leg muscles.

RESULTS

In normal subjects there was a well-defined sequence of events preceding the onset of leg elevation, beginning with a transfer of centre of foot pressure (CP), initially toward the moving leg and then back to the support side, followed by displacement of the trunk toward the support side. In the more severely affected parkinsonian patients, the amplitude of the initial displacement of CP was markedly reduced. The interval between the earliest force changes and the onset of leg elevation was prolonged and the relative timing of the kenematic adjustments during this interval was disrupted. In addition the alternating burst and periods of inhibition observed in the EMG recordings from the normal subjects were replaced by continuous tonic EMG activity.

CONCLUSIONS

These observations suggest that abnormalities in programming preparatory postural adjustments may contribute to postural instability in some patients with advanced Parkinson's disease.

Adaptive modification of oculomotor pursuit influences manual tracking responses

We have addressed the question of whether adaptively modifying the oculomotor response to a visual pursuit stimulus has an influence on a related manual tracking response. Subjects used their unseen right hand to track targets moving at constant velocities while visually fixating a stationary LED. Manual tracking performance was compared before and after a 20 min period during which smooth pursuit eye movements alone were adaptively enhanced by adding 50% of the instantaneous eye position signal to target position. Compared with the preadaptation trials, hand gain was markedly increased during the postadaptation period. These results imply that the adaptation occurred at a level common to both motor systems, probably in CNS structures concerned with visual motion processing.

Interactions between the eye and hand motor systems: disruptions due to cerebellar dysfunction

1. We tested the hypothesis that interactions occur between eye and hand movements produced in conjunction. This was accomplished by having human subjects with cerebellar dysfunction and age-matched controls perform two tasks: 1) tracking a moving target with the hand and 2) performing a pointing movement to intercept the target. Our prediction was that the inaccuracies that are characteristic of eye and hand movements generated in isolation by cerebellar subjects would be accentuated in each system during combined eye-hand tasks. 2. The cerebellar subjects took longer to respond to the onset of target motion in both tasks. This was true for both the eyes and hand, regardless of whether the eye and hand movements were generated in isolation or in conjunction with each other. 3. The cerebellar subjects also displayed a larger degree of error and/or variability in their hand movements than the control subjects. A significant amount of this increased variability was due to systematic changes in the trajectory of the hand during the critical periods leading up to and after each ocular saccade. These systematic changes were consistent with an overestimation of target velocity in the perifoveal visual field. 4. The increased variability of the cerebellar subjects' hand movements was markedly reduced by restricting eye movements. A similar reduction in variability occurred when vision of the hand was restricted in the tracking task. This effect was accompanied by improved eye movements. 5. For both sets of subjects the eye movements were affected by the hand movements produced in the tracking task. In particular, eye movement accuracy was improved in the controls and degraded in the cerebellar subjects when compared with the eye movements generated in isolation. In contrast, no changes were observed in the interception task. 6. Taken together, these results imply that a reciprocal interaction occurs between the eye and hand motor systems and/or that common "upstream" sites influence each of these systems in a similar manner. The functional anatomy and neurophysiological characteristics of several sites where such interactions may take place are discussed.

The contribution of retinal and extraretinal signals to manual tracking movements

We have assessed the contribution made by retinal and extraretinal signals when subjects used their hand to track targets moving at constant velocities. Comparisons were made between responses produced under the following conditions: (1) with full vision of the hand and unrestricted movement of the eyes, (2) without vision of the hand or (3) while visually fixating a stationary LED. Target velocity was varied in a pseudo-random order across trials. In each condition response latency decreased as target velocity was increased. There was a approximately 24 ms increase in latency when vision of the hand was removed or eye movements were restricted. Under normal conditions, subjects were able to accurately catch up to and match target velocity with their hand. When vision of the hand was removed, subjects lagged behind the target but were able to match target velocity. This deficit was eliminated when vision of the hand was made available for the beginning of the response. When subjects were required to visually fixate they could catch up to the target with their hand, but subsequently produced a steady state hand velocity that was greater than target velocity. When the LED was positioned such that the target started in the peripheral visual field, the overestimation of target velocity was evident from the beginning of the response: subjects produced initial accelerations with their hand that were significantly greater than in normal conditions. Finally, normal responses were produced when subjects were required to visually pursue a second target that moved at the same speed and in the same direction as the main target.(ABSTRACT TRUNCATED AT 250 WORDS)

Increased hepatocyte expression of hepatitis B virus transcription in patients with features of fibrosing cholestatic hepatitis

BACKGROUND

Recurrent hepatitis B after liver transplantation may be complicated by fibrosing cholestatic hepatitis. This syndrome is associated with rapid graft failure and is characterized by ballooning degeneration of hepatocytes and abundant viral antigen expression.

METHODS

To study this disorder further, in situ hybridization studies were performed on 36 liver biopsy specimens from 14 transplanted patients with recurrent hepatitis B and 18 nontransplanted controls with chronic hepatitis B. Biopsy specimens were scored for histological features and intensity of riboprobe hybridization signal to hepatitis B virus (HBV) DNA and RNA.

RESULTS

HBV DNA hybridization signals of 2+ to 3+ intensity were observed in 53% of the posttransplant biopsies but none of the nontransplanted samples (P < 0.001). HBV RNA signals of this intensity were found in 42% of the transplant biopsy specimens compared with 17% of the nontransplant specimens (P < 0.07). Features of fibrosing cholestatic hepatitis were noted in 12 biopsies; 11 of these displayed RNA signals of 2+ to 3+ intensity (92%) compared with 4 of 24 (17%) biopsy specimens without this diagnosis (P < 0.001). The level of hepatocyte RNA correlated with the extent of hepatocellular ballooning (P < 0.007).

CONCLUSIONS

These data suggest that fibrosing cholestatic hepatitis is associated with enhanced hepatitis B virus transcription and support a cytopathic role for the virus in the development of this syndrome.

Parkinson's disease: a test of the multifactorial etiologic hypothesis

We studied the relative etiologic importance upon the development of Parkinson's disease (PD) of occupational exposure to herbicides and other compounds, ionizing radiation exposure, family history of PD and essential tremor, smoking, and history of various viral and other medical conditions. We identified patients (n = 130) with neurologist-confirmed idiopathic PD through contacts with Calgary general hospitals, long-term care facilities, neurologists, the Movement Disorder Clinic, and the Parkinson's Society of Southern Alberta, and selected two matched (by sex and age +/- 2.5 years) community controls for each case by random digit dialing. We obtained lifetime work, chemical, radiation, medical, and smoking exposure histories and family histories of PD and essential tremor by personal interviews, and analyzed the data using conditional logistic regression for matched sets. After controlling for potential confounding and interaction between the exposure variables, using multivariate statistical methods, having a family history of PD was the strongest predictor of PD risk, followed by head trauma and then occupational herbicide use. Cases and controls did not differ in their previous exposures to smoking or ionizing radiation; family history of essential tremor; work-related contact with aluminum, carbon monoxide, cyanide, manganese, mercury, or mineral oils; or history of arteriosclerosis, chicken pox, encephalitis, hypertension, hypotension, measles, mumps, rubella, or Spanish flu. These results support the hypothesis of a multifactorial etiology for PD, probably involving genetic, environmental, trauma, and possibly other factors.

Determinants of serious liver disease among patients receiving low-dose methotrexate for rheumatoid arthritis

OBJECTIVE

To assess the risk of serious liver disease in patients with rheumatoid arthritis (RA) taking methotrexate (MTX).

METHODS

We surveyed members of the American College of Rheumatology to determine previous use of MTX in the treatment of rheumatoid arthritis and to identify cases of cirrhosis and liver failure. Cases were confirmed by review of pathology specimens, findings from diagnostic testing, and clinical presentations. A case-control study was then conducted to ascertain prognostic factors. Case and control medical records were reviewed for information on MTX therapy as well as other possible determinants of serious liver disease.

RESULTS

Twenty-four cases of cirrhosis and liver failure were identified, giving a 5-year cumulative incidence of approximately 1/1,000 treated patients. Six of the 24 patients had died: 4 died of the initial liver disease, 1 of hepatic complications of another illness, and 1 of unrelated causes. Two patients continue to have active liver disease. Late age at first use of MTX and duration of therapy with MTX were independent predictors of serious liver disease.

CONCLUSION

Serious liver disease is an uncommon, age- and dose-related complication of low-dose MTX therapy for RA.

Modulation of the soleus H-reflex during pedalling in normal humans and in patients with spinal spasticity

Soleus H-reflexes were recorded in 10 normal subjects and seven patients with spasticity caused by incomplete spinal cord injury while they pedalled on a stationary bicycle which had been modified to trigger electrical stimuli to the tibial nerve at eight precise points in the pedal cycle. Stimulus strength was adjusted to yield M-waves of constant amplitude at each pedal position. During active pedalling, all normal subjects showed modulation of the H-reflex with the amplitude being increased during the downstroke portion of the pedal cycle and the reflex suppressed or absent during the upstroke. This modulation was not present during passive pedalling, with the experimenter cranking the pedals by hand, or when the pedals were locked at each of the eight positions. In five of the seven patients with spasticity, there was reduced or absent modulation of the H-reflex during active pedalling and the reflex remained large during pedal upstroke. It is concluded that descending motor commands that produce patterned voluntary activity during pedalling normally cause cyclical gating of spinal reflexes by either presynaptic or postsynaptic inhibitory mechanisms. Loss of supraspinal control over these spinal inhibitory systems could result in failure to produce appropriate suppression of reflexes during patterned voluntary movements such as pedalling or walking, and may be an important factor contributing to the functional disability in spasticity.