Membrane region of surface IgM is not sufficient for transducing growth inhibitory signals in an immature B cell line WEHI-231

The murine B lymphoma line WEHI-231 is representative of immature B cells. Like normal immature B cells, WEHI-231 is susceptible to growth arrest following cross-linking of surface IgM (sIgM). Previously, we have shown using a WEHI-231 immunoglobulin (Ig) delta-transfectant that sIgD cross-linking failed to initiate growth arrest, in contrast to sIgM. In this report, we extend our research to investigate the structural requirement of Ig mu chain for regulating growth inhibition. Recombinant, chimeric Ig molecules delta/mu m and mu/delta m consisting of exons encoding extracellular delta and mu domains and membrane regions of different isotypes were constructed and introduced into WEHI-231 cells. A similar approach was used for sIgG2b-expressing transfectants. Our findings indicate that the mu m region is not sufficient for regulation of growth inhibition in WEHI-231 cells and suggest that additional extracellular region(s) of mu chain may be required for this response.

Monoclonal antiprothrombinase (3D4.3) prevents mortality from murine hepatitis virus (MHV-3) infection

The induction of monocyte/macrophage procoagulant activity (PCA) has been implicated in the pathogenesis of murine hepatitis virus strain 3 (MHV-3) infection and disease. Previously, we have shown that induction of PCA by MHV-3 correlated with resistance/susceptibility to infection in different mouse strains. In this study, all BALB/cJ mice that were infected with 10(3) plaque-forming units of MHV-3 developed severe liver disease and died within 96-120 h. Examination of the livers of these animals showed marked hepatic necrosis, deposition of fibrin, and cellular expression of PCA by direct immunofluorescence staining in areas of necrosis as well as in hepatic sinusoids. Splenic mononuclear cells recovered from these mice expressed high concentrations of PCA with time after infection. Infusion into mice of a high-titered monoclonal antibody that neutralized PCA (3D4.3) attenuated the development of hepatic necrosis and enhanced survival in a dose-dependent manner. All of the animals receiving 100 micrograms, and 44% and 22% of the animals that received 50 and 25 micrograms per day, respectively, survived for 10 d and made a full recovery. Administration of the antibody resulted in a dose-dependent reduction in fibrin deposition, PCA expression as detected by direct immunofluorescence staining and by a functional assay. In animals treated with high concentrations of antibody, titers of antibody to PCA fell from 87 +/- 15 micrograms/ml to 100 +/- 7 ng/ml during the active phase of the disease, consistent with sequestration due to binding of the immunoglobulin to cells expressing PCA. Surviving animals, when rechallenged with MHV-3, had a 40% mortality, consistent with the known rates of metabolism of immunoglobulin. This further suggested that protection was by a passive mechanism. The results reported here demonstrate that a neutralizing antibody to PCA protects animals from fulminant hepatitis and death associated with MHV-3 infection, and supports the notion that PCA is a potent inflammatory mediator that plays a pivotal role in the pathogenesis of liver injury resulting from MHV-3 infection.

Carotid body tumor

To better define the management and behavior of carotid body tumors, a 34-year surgical experience with 33 tumors in 30 patients was reviewed. There were 20 women and 10 men with an age range of 20 to 78 years. All but one presented with a neck mass. Arteriography was performed on 21 patients and was diagnostic in every case. There was no surgical mortality. Complications occurred in eight patients (27%), and one long-term neurologic deficit occurred. Three of 33 tumors were malignant, and aggressive resection of all approachable disease with radiotherapy for unresectable metastases led to prolonged survival in each case. Carotid body tumors present with neck mass. Arteriography is diagnostic and surgery is indicated. Even for malignant tumors and metastases, aggressive resection and radiotherapy are indicated.

Treatment of children with homozygous familial hypercholesterolemia: safety and efficacy of low-density lipoprotein apheresis

We evaluated the safety and efficacy of dextran sulfate low-density lipoprotein (LDL) apheresis in the treatment of three children (aged 6, 7, and 10 years) with severe familial homozygous hypercholesterolemia and undetectable LDL receptor activity. A total of 35 double plasma volume procedures were performed. The ranges of the mean decreases of the three patients in plasma lipid concentrations after LDL apheresis (p less than 0.0001) were as follows: total cholesterol, 76% to 79%; LDL-cholesterol, 78% to 81%; very low density lipoprotein cholesterol, 69% to 75%; high-density lipoprotein cholesterol, 27% to 40%; and triglycerides, 34% to 68%. There were statistically significant but clinically and biologically irrelevant changes in hematologic indexes, serum chemistry values, immunoglobulin levels, complement activity, and plasma concentrations of fat-soluble vitamins. Simple correlation analysis of the variables affecting total cholesterol removal showed significant correlation coefficients (r values) for preapheresis total cholesterol values (r = 0.70; p less than 0.01) and preapheresis LDL-cholesterol values (r = 0.61; p less than 0.01). A multiple regression model explained 82% of the variance based on the preapheresis cholesterol concentration, volume of whole blood processed, and the serum albumin concentration. Side effects of the LDL-apheresis treatments were rare and included abdominal cramping and urticaria. Two procedures were aborted because of intravenous access problems in the younger children. This study confirms that LDL apheresis using a dextran sulfate affinity column is efficacious in rapidly lowering total and LDL-cholesterol concentrations. Furthermore, the procedure is safe and well tolerated by children as young as 6 years of age. This treatment may prevent the progression of atherosclerosis in children with homozygous familial hypercholesterolemia and may therefore avert early death.

Transjugular liver biopsy in children

Transjugular liver biopsy is widely used in adult patients with liver disease when transthoracic needle liver biopsy is contraindicated by severe coagulopathy or ascites. It has not been used extensively in children. We report our experience with 30 consecutive transjugular liver biopsy procedures performed in 27 young patients at the Hospital for Sick Children in Toronto. Patient weights ranged from 14 to 91 kg (median = 42 kg); most patients had not yet attained adult size. A 9F catheter was used except in very small children, for whom we developed a 7F biopsy needle catheter. Most procedures were done with patients under general anesthesia. Specimens were obtained in all patients, and the procedure was tolerated well. A major complication occurred only once: perforation of the inferior vena cava, which was later repaired at liver transplantation. Minor complications included subcapsular extravasation of contrast agent in five patients and a small intrahepatic hematoma in one. Results of transjugular liver biopsy changed the diagnosis in 30% of patients and added valuable information about the disease process in most patients. Transjugular liver biopsy was an important component of emergency assessment for liver transplantation. Our results indicate that transjugular liver biopsy can be performed safely in children with liver disease if a skilled interventional radiologist and a well-equipped angiography suite are available. Histological studies in these patients enhance our understanding of the natural history of pediatric liver diseases.

Post-transplant recurrent hepatitis B viral liver disease. Viral-burden, steatoviral, and fibroviral hepatitis B

Recurrence of hepatitis is a well-documented complication of hepatitis B liver disease, post-transplantation. It is well established also that the earliest hepatocellular change is the appearance of hepatitis B viral (HBV) markers and that the disease is rapidly progressive. In this article on 17 liver transplants in 16 HBV positive patients with long-term follow-ups (100-1234 days), the distinctive pathologic features of this disease are emphasized: the extreme viral load, the steatosis, and/or fibrosis. An attempt to quantitate the magnitude of the viral burden was made and the result was a staggering figure. In one patient, an estimated 10(18) HBV core particles were present in the liver. One of two patterns of progression were noted. In four patients in addition to the massive nuclear hepatitis B core antigen (HBcAg) and cytoplasmic hepatitis B surface antigen (HBsAg) positivity, superimposed hepatitic changes led to diffuse hepatic fibrosis (fibroviral hepatitis B); and in another six patients, extraordinary hepatocellular viral marker positivity and steatosis were the hallmarks (steatoviral hepatitis B). Steatosis is not usually considered a feature of HBV liver pathology. These results suggest that more than one type of posttransfusion recurrent hepatitis B liver disease exists pathologically.

Assessment of neutrophil chemotaxis by laser and video densitometry

A laser densitometer and a video densitometer were used to evaluate neutrophil chemotaxis slides which were also assessed by the standard microscopic technique. A linear relationship was observed between cell number per high power field (HPF) and peak height by laser densitometry (r2 = 0.66) or peak area by video densitometry (r2 = 0.81). For wells containing more than 20 cells/HPF the least variability was observed with video densitometry. Quantitative results from neutrophil chemotaxis assays performed in 48-well microchambers can be obtained rapidly and conveniently by the use of commercially available video densitometers.

Sonographic findings of testicular teratoma with pathologic correlation

Testicular teratoma is a rare tumor in children. We recently encountered two boys, aged 18 months and 2 years respectively, with this tumor. Sonography revealed an intratesticular mass in both. The first revealed a predominantly cystic lesion with echogenic components along its wall. The second showed a complex mass occupying most of the right testicle, and containing several areas of calcifications and cysts. Excellent pathologic correlation was obtained in both. Preoperative diagnosis of testicular teratoma is possible if the characteristic features are recognized. The prognosis is good following orchiectomy in the pediatric patients.

The effect of eicosapentaenoic acid consumption on human neutrophil chemiluminescence

The effect of eicosapentaenoic acid (EPA) on the inflammatory potential of neutrophils was investigated by supplementing the diets of 12 subjects with 2.16 g of EPA or 12 g of olive oil per day for 4 weeks in a double blind crossover study. Neutrophil function as assessed by luminol enhanced chemiluminescence responses to platelet-activating factor (PAF) and formyl-methionyl-leucyl-phenylalanine (FMLP) was significantly reduced after EPA but not after olive oil consumption in the subjects who consumed EPA first. In contrast, EPA had no significant effect on neutrophil chemiluminescence in the subjects who consumed olive oil first. Dietary supplementation with EPA inhibits neutrophil responses to inflammatory mediators such as PAF while other fatty acids appear to modify the effects of EPA.

The interaction of acetylcholine and histamine on human bronchial smooth muscle contraction

The interaction of histamine (Hist) and acetylcholine (ACh) on human isolated bronchial smooth muscle (HIBSM) contraction, and the influence of the epithelium, was assessed using HIBSM obtained from 15 patients undergoing thoracotomy. Cumulative concentration effect curves for ACh and Hist, together with combinations of equipotent concentrations of both agonists, were generated using both epithelium-intact and epithelium-denuded HIBSM. In epithelium-denuded HIBSM both ACh (p less than 0.05) and Hist (p less than 0.005) produced a significantly enhanced maximal response and a 2.1 fold increase in the potency of ACh (p less than 0.02, n = 13). When ACh and Hist were added simultaneously, in equipotent concentrations, to epithelium-intact HIBSM, a significantly less (p less than 0.0005, n = 13) than additive response occurred with only 60% of the predicted maximum response being observed. However, following epithelium removal, an additive interaction between the two agonists (n = 8) occurred. Using HIBSM from five of the original 15 patients, similar experiments were performed to determine the influence of the muscarinic receptor antagonist atropine (0.1 microM) and the H1 receptor antagonist mepyramine (10 microM). Both resulted in a significantly less than additive interaction (40-50% of predicted tensions). Similar experiments were also performed in the presence of the cyclo-oxygenase inhibitor indomethacin (5 microM) and these failed to reverse the inhibition observed in HIBSM contraction (n = 5). The inhibitory interaction between ACh and Hist appears to be epithelium dependent and is not mediated via the release of prostanoids. Thus, there appears to be a complex interaction between contractile agonists and the epithelium, which is not just a simple summation of the activation of individual receptors on HIBSM.

The interaction of acetylcholine and histamine on human bronchial smooth muscle contraction

The interaction of histamine (Hist) and acetylcholine (ACh) on human isolated bronchial smooth muscle (HIBSM) contraction, and the influence of the epithelium, was assessed using HIBSM obtained from 15 patients undergoing thoracotomy. Cumulative concentration effect curves for ACh and Hist, together with combinations of equipotent concentrations of both agonists, were generated using both epithelium-intact and epithelium-denuded HIBSM. In epithelium-denuded HIBSM both ACh (p less than 0.05) and Hist (p less than 0.005) produced a significantly enhanced maximal response and a 2.1 fold increase in the potency of ACh (p less than 0.02, n = 13). When ACh and Hist were added simultaneously, in equipotent concentrations, to epithelium-intact HIBSM, a significantly less (p less than 0.0005, n = 13) than additive response occurred with only 60% of the predicted maximum response being observed. However, following epithelium removal, an additive interaction between the two agonists (n = 8) occurred. Using HIBSM from five of the original 15 patients, similar experiments were performed to determine the influence of the muscarinic receptor antagonist atropine (0.1 microM) and the H1 receptor antagonist mepyramine (10 microM). Both resulted in a significantly less than additive interaction (40-50% of predicted tensions). Similar experiments were also performed in the presence of the cyclo-oxygenase inhibitor indomethacin (5 microM) and these failed to reverse the inhibition observed in HIBSM contraction (n = 5). The inhibitory interaction between ACh and Hist appears to be epithelium dependent and is not mediated via the release of prostanoids. Thus, there appears to be a complex interaction between contractile agonists and the epithelium, which is not just a simple summation of the activation of individual receptors on HIBSM.

Permeabilized hepatocyte couplets. Adenosine triphosphate-dependent bile canalicular contractions and a circumferential pericanalicular microfilament belt demonstrated

The motility of bile canaliculi was examined in hepatocyte couplets permeabilized with palmitoyl lysophosphatidyl choline in a dosage regimen that drastically affected secretory function, yet maintained relative integrity of the cellular cytoskeleton. The permeabilized cells showed no exclusion of trypan blue, notable cytoplasmic organelle and membrane damage, and no uptake or secretion of either fluorescein diacetate or sodium fluorescein. However, bile canalicular structure remained relatively intact and actin and myosin were localized immunocytochemically in the pericanalicular region. Coincident with the administration of 1 mM ATP, 2 mM Mg2+, and 1 microM Ca2+, the canaliculi contracted with partial or complete luminal closure. ADP, AMP, or AMP-PCP could not be substituted for ATP. A dose-dependent relationship was shown between ATP concentration and canalicular contraction rate. The permeabilization procedure also provided enhanced visualization of pericanalicular microfilaments, believed to be actin filaments, and their organization into two layers: an inner membrane-associated network, and an outer filament bundle that inserted into belt junctions (zonulae adherentes). The organization of the microfilament belt of contiguous hepatocytes was such that it formed a circumferential band of microfilaments around the canaliculus. It is analogous to contractile filament belts found in the apical terminal web region of other epithelia. It was also observed that with canalicular luminal closure, there was a change in the organization of the pericanalicular microfilaments. It is concluded that in hepatocyte couplets, differential sensitivity of cell components to permeabilization can be achieved with palmitoyl lysophosphatidyl choline. In addition, the results provide evidence that the bile canaliculus has the capacity to be a contractile structure even in the absence of secretion, that canalicular contraction is ATP-dependent, and hence is a dynamic process.

Motility of bile canaliculi in the living animal: implications for bile flow

Modern fluorescence microscopic techniques were used to image the bile canalicular system in the intact rat liver, in vivo. By combining the use of sodium fluorescein secretion into bile, with digitally enhanced fluorescence microscopy and time-lapse video, it was possible to capture and record the canalicular motility events that accompany the secretion of bile in life. Active bile canalicular contractions were found predominantly in zone 1 (periportal) hepatocytes of the liver. The contractile movements were repetitive, forceful, and appeared unidirectional moving bile in a direction towards the portal bile ducts. Contractions were not seen in the network of canaliculi on the surface of the liver. Cytochalasin B administration resulted in reduced canalicular motility, progressive dilation of zone 1 canaliculi, and impairment of bile flow. Canalicular dilations invariably involved the branch points of the canalicular network. The findings add substantively to previous in vitro studies using couplets, and suggest that canalicular contractions contribute physiologically to bile flow in the liver.

Correlation of donor nutritional status with sinusoidal lining cell viability and liver function in the rat

We have demonstrated that the sinusoidal lining cell injury sustained by rat liver allografts during hypothermic storage is a critical determinant of graft viability. The present study was designed to examine the effect of donor nutritional status on hepatic microcirculation and graft function. Rat livers from four nutritional groups (group I, fasted; group II, fed; group III, intraperitoneal glucose; and group IV, fed plus intraperitoneal glucose) were excised and stored for 24 hr in Marshall's isotonic citrate solution. Then the livers were perfused under anoxic conditions with trypan blue. The percentage of nonviable SLC in each group was 26.7 +/- 8.1, 24.9 +/- 7.9, 17.6 +/- 6.9, and 5.9 +/- 1.9 in groups I, II, III, and IV respectively; i.e., there was a significant improvement in SLC viability with nutritional repletion in group IV. Electron microscopy was performed on livers from groups I and IV following 30-hr preservation in University of Wisconsin solution and after 16-hr preservation in Marshall's isotonic citrate solution. Biopsies were taken at the end of storage and after 1 hr of reperfusion at 37 degrees C. At the end of preservation group IV livers contained glycogen and had much more normal liver ultrastructure than group I livers. After reperfusion there was partial recovery of normal SLC morphology in both groups and depletion of glycogen in group IV. Liver function was studied on the isolated perfused rat liver system at 37 degrees C following 30-hr storage in UW solution. Transaminase release into the perfusate was significantly lower in nutritionally repleted livers than in livers from fasted animals. A significant reduction in perfusate platelet count occurred only in livers from fasted animals. The results show that nutritional repletion can reduce the injury of cold preservation to both hepatocytes and endothelial cells and improve liver function in the postpreservation period.

Fibrolamellar carcinoma of the liver in a patient with Fanconi anemia

A 9-year-old boy with Fanconi anemia treated with oxymethalone, a synthetic androgen, died of intracerebral hemorrhage. At autopsy, the liver contained several adenomas and a large fibrolamellar hepatocellular carcinoma, as well as phlebectatic peliosis hepatis. The 11 previously reported cases of hepatocellular carcinoma in Fanconi anemia were not, apparently, of the fibrolamellar type, which has a better prognosis, occurs in children of both sexes, and generally is not associated with cirrhosis. The malignant potential of primary liver tumors associated with Fanconi anemia as well as the nature of their relationship to Fanconi anemia and to anabolic steroid therapy is discussed.

Syncytial giant-cell hepatitis. Sporadic hepatitis with distinctive pathological features, a severe clinical course, and paramyxoviral features

BACKGROUND AND METHODS

We describe a new form of hepatitis, occurring in 10 patients over a period of six years, characterized clinically by manifestations of severe hepatitis, histologically by large syncytial giant hepatocytes, and ultrastructurally by intracytoplasmic structures consistent with paramyxoviral nucleocapsids.

RESULTS

The patients ranged in age from 5 months to 41 years. The tentative clinical diagnosis before biopsy was non-A, non-B hepatitis in five patients and autoimmune chronic active hepatitis in the others. Five patients underwent liver transplantation; the others died. The diagnosis of syncytial giant-cell hepatitis was established pathologically. The liver cords were replaced in all 10 patients by syncytial giant cells with up to 30 nuclei. In 8 of the 10 the cytoplasm contained pleomorphic particles of 150 to 250 microns, filamentous strands, and particles of 14 to 17 nm with peripherally disposed spikes resembling paramyxoviral nucleocapsids. Structures resembling degenerated forms were found in the other two patients. One of two chimpanzees injected with a liver homogenate from the index patient had an increase in the titer of paramyxoviral antibodies, probably an anamnestic reaction to previous paramyxoviral infection, suggesting that a paramyxoviral antigen but not viable virus was present in the liver homogenate.

CONCLUSIONS

Although further virologic studies will be required for precise classification, we believe that paramyxoviruses should be considered in patients with severe sporadic hepatitis.

Neonatal hepatitis syndrome with paucity of interlobular bile ducts in cystic fibrosis

A male infant presenting with neonatal hepatitis syndrome, characterized by conjugated hyperbilirubinemia and very mild liver function test abnormalities, at 2 weeks of age was found to have no excretion of radioisotope into the intestinal tract on hepatobiliary scan. Liver biopsy revealed severe interlobular bile duct paucity. Other features of Alagille's syndrome were not present; other conditions frequently associated with interlobular bile duct paucity were also excluded. Subsequently, the infant was found to have cystic fibrosis. Cystic fibrosis is thus another disease that may be associated with paucity of interlobular bile ducts presenting as neonatal hepatitis syndrome, and this represents a different pathogenesis of cholestatic jaundice in neonates with cystic fibrosis besides those previously recognized.

Pneumothorax: treatment by small-lumen catheter aspiration

To assess the efficacy of simple aspiration as a treatment for pneumothorax, 40 consecutive pneumothoraces (28 spontaneous, 12 iatrogenic, all estimated at greater than or equal to 20% collapse on visual inspection of the chest X-ray) in 38 symptomatic patients were treated initially by small-lumen catheter (SLC) aspiration. SLC aspiration avoided the need for large-lumen intercostal catheter (LIC) underwater drainage in 28 cases (70%)--20 of 28 spontaneous and eight of 12 iatrogenic pneumothoraces. Outcome was not predicted by clinical variables or pneumothorax size, whereas an initial aspirate volume of less than or equal to 4 L (n = 33) was predictable of success in 28 cases (85%). Minor local subcutaneous emphysema and vasovagal reactions were encountered infrequently but with similar frequency to LIC drainage. No episodes of re-expansion pulmonary oedema occurred. The results confirm previous reports of the efficacy of simple aspiration as a treatment for spontaneous or iatrogenic pneumothorax. Initial treatment by SLC aspiration is recommended for all but life-threatening presentations of pneumothorax. Although not encountered in this study, the potential risk of re-expansion pulmonary oedema suggests that patients should be observed closely for four hours after aspiration.

Congenital abnormalities of the lymphatic system: a new clinical classification

The numerous clinical presentations of congenital abnormalities of the lymphatic system in children and the confusing terminology used to describe their pathologic diagnoses impede the physician's understanding of the condition. The clinical classification based on the actual symptoms of the congenital problems we have presented here should help the physician identify the specific abnormality and a potential treatment. Future research should concentrate on the specific causes and the treatment of these congenital abnormalities.

Liver cell dysplasia and early liver transplantation in hereditary tyrosinemia

Two cases of hereditary tyrosinemia presented with ascites and coagulopathy in infancy. Both patients underwent liver transplantation at the age of 25 and 36 mo, respectively. Both cases had normal liver function 37 and 24 mo later. The native liver in each case showed mixed micro- and macronodular cirrhosis with hepatocellular dysplasia, including both the large and small cell varieties. One of the subjects had also shown dysplasia in a prior liver biopsy. We compared the hepatic morphology with that from two other cases from our autopsy files. One of these (a female, 9 mo old) showed dysplasia, and the other (her male sibling, 4 yr old) had a liver cell carcinoma with lung metastases. These observations confirm prior reports that neoplastic transformation occurs early in the natural history of hereditary tyrosinemia despite meticulous dietary management and other supportive treatment. With the detection of liver cell dysplasia, efforts should be intensified to find an appropriate donor. Liver transplantation cures the hepatic disease and should be performed before malignancy develops.

Phenobarbital hepatotoxicity in an 8-month-old infant

Severe hepatotoxicity from phenobarbital occurred in an infant boy who had a complicated illness with chronic bilateral subdural hematomas and sepsis. Skin rash began after 2 weeks of treatment, and signs of hepatocellular failure developed 3 weeks after phenobarbital had been started. Signs of severe liver disease included elevated aminotransferases, conjugated hyperbilirubinemia, significant coagulopathy, hepatosplenomegaly and ascites. Other features of this adverse drug reaction were unremitting fever, leukocytosis with eosinophilia and atypical lymphocytosis, and proteinuria. Sepsis, viral hepatitis, and metabolic liver disease were excluded. The child was on no other medication and had been previously well. In-vitro rechallenge of the patient's lymphocytes with cytochrome P-450 generated metabolites of phenobarbital showed extensive cytotoxicity compared to control. These data support the hypothesis that a defect in drug detoxification was responsible for the child's susceptibility to this drug hepatotoxicity.