Expression of the cyclin-dependent kinase inhibitors p16INK4, p15INK4B and p21WAF1/CIP1 in human breast cancer

Aberrant cyclin expression has been implicated in oncogenesis in a number of human cancers. Since altered function of regulators of cyclin-dependent kinase (CDK) activity other than cyclins, in particular CDK inhibitors, might play a similar role in oncogenesis, we examined the expression and regulation of the CDK inhibitors p16INK4, p15INK4B and p21WAF1/CIP1 in human breast cancer cell lines. Both the INK4 and INK4B genes were homozygously deleted in 3 cell lines, while INK4 alone was deleted in 2 cell lines. A further 2 cell lines displayed loss of an allele at this locus, and in 1 of these the remaining allele contained a mis-sense mutation within the coding region of the p16INK4 protein. The majority of cell lines examined, including 2 normal mammary epithelial cell strains, expressed low levels of INK4 mRNA and low or undetectable levels of INK4B mRNA. However, INK4 mRNA was expressed at high levels in 5 cell lines, and this was associated with deletion or inactivation of the retinoblastoma susceptibility gene product pRB but not with mutation of TP53. No deletions of the WAF1/CIP1 gene were observed, but WAF1/CIP1 mRNA levels were reduced in cell lines with TP53 mutation. Transfection of a p16INK4 expression vector into MDA-MB-231 cells lacking the INK4 gene failed to produce any p16INK4-expressing cell lines, suggesting that such cells were selected against in continuous culture. Despite the frequent deletion of INK4 in breast cancer cell lines, no evidence was obtained for INK4 deletions in DNA from 45 primary breast carcinomas. Thus, homozygous deletion of the INK4 gene appears to be a rare event in primary breast cancer.

Clinical management of recurrent hepatocellular carcinoma

OBJECTIVE

The aim of this study was to evaluate the long-term benefits of the aggressive treatments with resection or transarterial chemoembolization (TACE) for recurrent hepatocellular carcinoma (HCC).

SUMMARY BACKGROUND DATA

Primary HCC is one of the most fatal malignancies in Taiwan. The result of resection for HCC remains unsatisfactory, primarily due to the high recurrence rate. To improve surgical results, recurrent HCC must be treated with aggressive resection or TACE.

METHODS

The authors evaluated the results of repeated hepatic resection among 25 patients with recurrent HCC and of TACE among 12 patients with resectable recurrent HCC. The outcomes of an additional 64 patients with unresectable recurrent HCC were also evaluated.

RESULTS

During the follow-up period from 2-112 months, 52% (13/25) of patients receiving repeat resection (group 1) were alive, whereas 42% (5/12) of patients receiving TACE (group 2) were alive. No perioperative deaths within 30 days after surgery occurred in the repeated resection group. The cumulative survival rates at 1, 2, 3, and 5 years after the first operation were 92%, 84%, 71.6%, and 65.1% in group 1 and 83.3%, 75%, 75%, and 22.5% in group 2. The survival rates at 6 months and at 1, 2, and 3 years after recurrence were 92%, 72%, 64%, and 44.8% in group 1 and 83.3%, 75%, 66.7%, and 48% in group 2. The survival of patients with unresectable recurrent HCC was much worse: 1-, 2-, 3-, and 5-year survival after surgery was 57.8%, 29.8%, 15.5%, and 0%; and 6-month and 1-, 2-, and 3-year survival after recurrence was 46.5%, 29.2%, 12.5% and 7.8%.

CONCLUSIONS

More aggressive treatment with repeated hepatic resection can prolong survival time after recurrence of HCC in selected patients. However, TACE can also achieve good results although it is not thought of as curative.

Fulminant hepatic failure in a renal transplant recipient with positive hepatitis B surface antigens: a case report of fibrosing cholestatic hepatitis

This 28-year-old male, a hepatitis B virus (HBV) carrier, received cadaveric renal transplantation and was maintained on cyclosporin A and prednisolone. Jaundice occurred 8 months after the transplantation and he died 2 weeks later due to hepatic failure. The liver histologic findings were compatible with fibrosing cholestatic hepatitis (FCH), which is caused by HBV and has only been reported in liver allografts of orthotopic liver transplantations. This is the first case of FCH developing in a renal transplant recipient. The report illustrates that (1) FCH is also a unique histologic entity in renal transplantations; (2) FCH might occur in a liver chronically infected by HBV without co-existing hepatitis D virus; and (3) FCH can cause fulminant hepatic failure within one year after transplantation while the patient is still in an immunosuppressed state.

Experiences in surgical management of cavernous hemangioma of the liver

BACKGROUND/AIMS

Observation is usually recommended for managing patients with cavernous hemangioma of the liver. To assess the indications for surgical management, we make a retrospective analysis.

PATIENTS AND METHODS

There were 14 patients with cavernous hemangioma of the liver who were surgically treated in National Taiwan University Hospital from 1984 to 1993.

RESULTS

The surgical indications included uncertain diagnosis in 10 patients, progressive tumor enlargement in two, symptomatic tumor in one and subcapsular bleeding in one. The tumors were 2-15 cm in diameter and the median was 6 cm. The operation procedures included atypical hepatectomy in 6 patients, lateral segmentectomy in 4, right lobectomy in one, extended right lobectomy in one and open biopsy in two. There was no mortality. Wound infection occurred in one patient. The average blood transfusion was 0.79 unit (range: 0-3 units)(1 unit=500 ml). The postoperative hospital stay was 13.2 days (range: 10-18 days).

CONCLUSION

Surgical management of cavernous hemangioma of the liver is safe.

Epidermal growth factor receptor immunoreactivity in gallbladder and extrahepatic biliary tract tumours

Elevated levels of epidermal growth factor receptor (EGFR), a transmembrane protein tyrosine kinase receptor, are found in carcinomas from various sites of the body. We investigated the expression of EGFR in carcinoma of the gallbladder (n = 13), common bile duct (n = 7) and ampulla of Vater (n = 9). Non-malignant conditions investigated include chronic cholecystitis (n = 11), gallbladder dysplasia (n = 3) and adenoma (n = 1), and ampullary carcinoma in situ (CIS) (n = 2). Routine immunohistochemistry was employed using a monoclonal antibody against the EGFR protein. Immunostaining was assessed according to both intensity and extent of staining of cells. There was strong immunoreactivity for all gallbladder carcinoma and adenoma, the majority of common bile duct (n = 6; 86%) and ampullary (n = 6; 67%) carcinoma. In contrast, all cases of gallbladder dysplasia, the majority of cases of chronic cholecystitis (n = 7; 64%) and ampullary CIS (n = 2; 67%) had only weak to moderate immunoreactivity. The pattern of immunoreactivity was one of diffuse cytoplasmic and membranous staining. In conclusion, EGFR expression is increased in both gallbladder, common bile duct and ampullary carcinomas but not in non-malignant conditions of the gallbladder and biliary tract. These findings suggest that EGFR overexpression occurs late in the sequential development of gallbladder and biliary tract cancers.

Derotational femoral shortening for developmental dislocation of the hip: special indications and results in the child younger than 2 years

Combining derotational femoral shortening osteotomy with open reduction to reduce the incidence of redislocation and avascular necrosis (AVN) in developmental dislocation of the hip (DDH) was first used only for older children. In special circumstances (teratologic dislocation, syndrome-related DDH, difficult home environment), we have combined femoral shortening with open reduction in 15 children (20 hips) ranging in age from 5 to 23 months old. Fourteen hips required concurrent pelvic osteotomy. Complications included partial AVN in two hips, residual subluxation requiring acetabular osteotomy in two hips, and residual dysplasia in two hips. Radiographic evaluation by the Severin method revealed 15 good or excellent hips and five hips rated fair or less. Hips reduced without pelvic osteotomy produced better radiographic results than those treated with a concomitant augmentation acetabuloplasty (Albee). This procedure can injure the growth centers of the acetabular rim in a very young child. Derotational femoral shortening can be used in special circumstances to achieve reduction in DDH in children younger than 2 years. The surgery is technically demanding, and the surgeon should have extensive prior experience using this method in older children.

Electroosmotic control of chiral separation in capillary zone electrophoresis

The resolution in capillary zone electrophoresis (CZE), with the assumption of diffusion control only, is strongly dependent on the direction and magnitude of electroosmotic flow. In fact, excellent separation resolution will be obtained if the electroosmotic flow is in the opposite direction of the electrophoretic migration. By applying various radial electric potential gradients across the capillary wall, the direct control of the zeta potential and the electroosmotic flow results in a great enhancement of chiral resolution in cyclodextrin-modified CZE. All 12 basic chiral drugs, including (+/-)-ephedrine, (+/-)-pseudoephedrine, (+/-)-norephedrine, (+/-)-epinephrine, (+/-)-norepinephrine, and (+/-)-isoproterenol, are separated and resolved within 22 min of the analysis time. There is no additional band broadening and dispersion introduced by the direct control of electroosmosis with the application of various radial electric potential gradients.

T-cell--mediated autologous hepatocytotoxicity in patients with chronic hepatitis C virus infection

Virus-specific cytotoxic T lymphocytes (CTLs) have been suggested to be responsible for the liver injuries in patients with hepatitis C virus (HCV) infection. However, there has been no report of direct evidence to substantiate this hypothesis. In this study, we performed in vitro autologous hepatocytotoxicity assay in 45 patients to examine a possible role of CTLs to HCV-infected live cells. The data were correlated with histology activity index of liver biopsy specimens. Lymphocyte subsets and hepatocyte expression of human major histocompatibility complex antigens class I and class II (HLA-I and HLA-II) were also evaluated. The immunohistochemical study showed more prominent HLA-I expression than HLA-II on hepatocytes (mean score +/- SEM:2.34 +/- 0.11 vs. 0.42 +/- 0.08; P < .01). The lymphocyte subset analysis showed that CD8+ T cells were dominant in the lobular areas showing spotty necrosis, whereas CD4+ T cells were prominent in the portal and periportal areas (P < .01). Most patients had a significant T cell-mediated cytotoxicity to hepatocytes as compared with non-T cells (percentage cytotoxicity +/- SEM:46.4 +/- 2.3 vs. 13.8 +/- 2.7; P < .001). T cell-mediated hepatocytotoxicity had a linear correlation with HAI (P < .05). The T cell-mediated cytotoxicity could be blocked by anti-CD8 (43.7% vs. 18.5%, P < .05) but not by anti-CD4 or anti-HLA-II monoclonal antibodies. These findings strongly suggest that HLA-I-restricted, CD8+ T cell-mediated hepatocytotoxicity is an important pathogenetic mechanism in patients with chronic HCV infection.

p53 in cutaneous melanoma: immunoreactivity and correlation with prognosis

p53 protein immunoreactivity was investigated in cutaneous Spitz naevi (n = 7), superficial spreading (n = 21) and nodular (n = 6) melanomas using the monoclonal antibody DO-7. Nuclear immunostaining for p53 protein was observed in 41% of all the melanomas but not in any of the Spitz naevi studied. This difference in p53 immunoreactivity appeared statistically significant (P = 0.0001; chi 2 test). There were also differences in p53 immunoreactivity between superficial spreading and nodular melanomas (P = 0.001, chi 2 test), where up to 38% of superficial spreading melanomas and 50% of nodular melanomas had demonstrated p53 nuclear immunostaining. An apparently significant correlation was observed between melanomas with poor prognostic histological indices and p53 immunoreactivity (P = 0.0016; chi 2 test). In conclusion, increased p53 protein immunoreactivity is found in melanomas and is associated with poorer prognosis. The differences in p53 immunohistological expression between cutaneous melanomas and Spitz naevi suggest that alterations of the protein may be important in the pathogenesis of the tumour.

Quantitative analysis of intraepithelial large granular lymphocyte distribution and maternofetal cellular interactions in the synepitheliochorial placenta of the deer

Intraepithelial lymphocytes are a constant feature of ruminant uterine epithelium in nonpregnant animals. Quantitation in 6 species of deer shows that the proportion of large granular lymphocytes (LGL) in this population increases markedly and continuously from the earliest implantation to the latest (midpregnant) stage examined. The size of individual granules also increases. Fetal trophectodermal binucleate cells are also present from the earliest stage in all deer examined and follow a usual ruminant life cycle: migrating and fusing with uterine epithelial cells to form trinucleate cells before releasing their granules to the maternal compartment and finally degenerating and being reabsorbed by the trophectodermal uninucleate cells. Deer LGLs were usually closely associated with the degranulating fetomaternal hybrid trinucleate cells but showed no ultrastructural changes themselves. This association indicates a dynamic interaction between deer LGL and trinucleate cells which could serve as one of the factors restricting the extent of trinucleate cell progression to a continuous syncytium as found in sheep and goats.

Core antigen mutations of human hepatitis B virus in hepatomas accumulate in MHC class II-restricted T cell epitopes

Despite the extensive molecular information on serum-derived human hepatitis B viruses (HBV), liver-derived replicative HBV genomes have remained largely uninvestigated. We have examined the sequences of the entire core antigen (nucleocapsid) of liver-derived HBVs in 15 different hepatoma patients. Bona fide mutations, rather than subtype polymorphism, have been identified based on the high-frequency occurrence of structural differences from wild type at the highly evolutionarily conserved positions, instead of at the positions known to contain genetic heterogeneity among different isolates from different geographic locations. The distribution of these naturally occurring mutations of HBV core gene appears to be nonrandom and is found predominantly within three major (I, IV, and V) and four minor domains (II, III, VI, and VII). In general, domain IV mutations correlate with domain V mutations. The replicative HBV DNAs tend to accumulate a higher number of mutated core domains than the integrated HBV DNAs. At the domain level, there is no significant difference in HBV core mutation frequencies between the liver tumors and the adjacent nontumorous livers. Strikingly, domains I, III, and V coincide with three major known T cell epitopes within the core protein in acute and chronic hepatitis B patients. Furthermore, these domains coincide with HLA class II-restricted T cell epitopes, rather than with the conventional HLA class I-restricted epitopes of cytotoxic T lymphocytes. Our results support the hypothesis that HBV core antigen variants can accomplish immunoevasion via accumulated escape mutations. In addition, they also provide a potential molecular explanation for the maintenance of persistent infection of human hepatitis B virus in chronic carriers.

Emphysematous gastritis secondary to acute gastric dilatation

Emphysematous gastritis is a life-threatening disease. Although rare in incidence, it has a fulminating course with a high mortality rate. A case of a 58 year old male with emphysematous gastritis is reported. Initially, he presented with acute gastric dilatation secondary to anorexia/bulimia-like behaviour. Later, emphysematous gastritis developed. The abdominal sonographic findings, which have not been previously described in the literature, showed intramural gas and gastric wall thickening. After receiving a total gastrectomy, he had a satisfactory outcome. The present report discusses the possible aetiologic relationship between acute gastric dilatation and emphysematous gastritis, and suggests abdominal sonography to be the first choice of diagnostic measure for patients and the intramural gas in the gastric wall. This is the first case of emphysematous gastritis diagnosed by abdominal sonography.

Primary cutaneous Ewing's sarcoma/peripheral primitive neuroectodermal tumors in childhood. A molecular, cytogenetic, and immunohistochemical study

Childhood cutaneous and subcutaneous malignancies are rare and include metastatic tumors of diverse histogenesis as well as primary lesions, such as sweat gland carcinomas. Some cutaneous malignancies exhibit a small round cell tumor morphology with few definitive differentiating features; they can thus pose a significant diagnostic problem. We describe two primary malignancies of the skin and superficial subcutis, which were originally diagnosed as sweat gland carcinomas on the basis of their morphological features. A cytogenetic analysis performed on one of these lesions showed the t(11;22)(q24;q12) rearrangement, believed to be unique to the Ewing's sarcoma/peripheral primitive neuroectodermal tumor (ES/pPNET) group of neoplasms. In view of this unexpected result, reverse transcriptase-polymerase chain reaction analysis was performed on both lesions and showed that they expressed EWS/FLI-1 fusion gene mRNA transcripts, the molecular equivalent of t(11;22)(q24;q12). The two tumors also had an immunohistochemical profile suggesting ES/pPNET, including strong expression of the MIC2 antigen. Both patients were treated with wide local excision, and one was given a course of chemotherapy. Neither patient showed evidence of tumor elsewhere after follow-up periods of 2 years and 16 years. These findings suggest that these tumors are indeed a form of primary ES/pPNET arising in the skin or superficial subcutis, which may be of low-grade malignancy and curable by local surgery.

In vitro assembly of infectious virions of double-stranded DNA phage phi 29 from cloned gene products and synthetic nucleic acids

Up to 6 x 10(7) PFU of infectious virions of the double-stranded DNA bacteriophage phi 29 per ml were assembled in vitro, with 11 proteins derived from cloned genes and nucleic acids synthesized separately. The genomic DNA-gp3 protein conjugate was efficiently packaged into a purified recombinant procapsid with the aid of a small viral RNA (pRNA) transcript, a DNA-packaging ATPase (gp16), and ATP. The DNA-filled capsids were subsequently converted into infectious virions after the addition of four more recombinant proteins for neck and tail assembly. Electron microscopy and genome restriction mapping confirmed the identity of the infectious phi 29 virions synthesized in this system. A nonstructural protein, gp13, was indispensable for the assembly of infectious virions. The overproduced tail protein gp9 was present in solution in mostly dimeric form and was purified to homogeneity. The purified gp9 was biologically active for in vitro phi 29 assembly. Higher-order concentration dependence of in vitro phi 29 assembly on gp9 suggests that a complete tail did not form before attaching to the DNA-filled capsid, a result contrary to earlier findings for phages T4 and lambda. The work described here constitutes an extremely sensitive assay system for the analysis of components in phi 29 assembly and dissection of functional domains of structural components, enzymes, and pRNA (C.-S. Lee and P. Guo, Virology 202:1039-1042, 1995). Efficient packaging of foreign DNA in vitro and synthesis of viral particles from recombinant proteins facilitate the development of phi 29 as an in vivo gene delivery system. The finding that purified tail protein was able to incorporate into infectious virions might allow the construction of chimeric phi 29 carrying a tail fused to ligands for specific receptor of human cells.

Sequential interactions of structural proteins in phage phi 29 procapsid assembly

The mechanism of viral capsid assembly is an intriguing problem because of its fundamental importance to research on synthetic viral particle vaccines, gene delivery systems, antiviral drugs, chimeric viruses displaying antigens or ligands, and the study of macromolecular interactions. The genes coding for the scaffolding (gp7), capsid (gp8), and portal vertex (gp10) proteins of the procapsid of bacteriophage phi 29 of Bacillus subtilis were expressed in Escherichia coli individually or in combination to study the mechanism of phi 29 procapsid assembly. When expressed alone, gp7 existed as a soluble monomer, gp8 aggregated into inclusion bodies, and gp10 formed the portal vertex. Circular dichroisin spectrum analysis indicated that gp7 is mainly composed of alpha helices. When two of the proteins were coexpressed, gp7 and gp8 assembled into procapsid-like particles with variable sizes and shapes, gp7 and gp10 formed unstable complexes, and gp8 and gp10 did not interact. These results suggested that gp7 served as a bridge for gp8 and gp10. When gp7, gp8, and gp10 were coexpressed, active procapsids were produced. Complementation of extracts containing one or two structural components could not produce active procapsids, indicating that no stable intermediates were formed. A dimeric gp7 concatemer promoted the solubility of gp8 but was inactive in the assembly of procapsid or procapsid-like particles. Mutation at the C terminus of gp7 prevented it from interacting with gp8, indicating that this part of gp7 may be important for interaction with gp8. Coexpression of the portal protein (gp20) of phage T4 with phi 29 gp7 and gp8 revealed the lack of interaction between T4 gp20 and phi 29 gp7 and/or gp8. Perturbing the ratio of the three structural proteins by duplicating one or another gene did not reduce the yield of potentially infectious particles. Changing of the order of gene arrangement in plasmids did not affect the formation of active procapsids significantly. These results indicate that phi 29 procapsid assembly deviated from the single-assembly pathway and that coexistence of all three components with a threshold concentration was required for procapsid assembly. The trimolecular interaction was so rapid that no true intermediates could be isolated. This finding is in accord with the result of capsid assembly obtained by the equilibrium model proposed by A. Zlotnick (J. Mol. Biol. 241:59-67, 1994).

Audiological profiles and Menière's disease

Pure-tone audiograms of 501 patients with preoperative Menière's disease were analyzed. Age of onset and incidence of bilaterality were studied. The most common audiogram was the peak-type (50.26%), next the falling-type (26.26%), and then the dip-type (9.24%). Although few papers mention this peak audiogram, we suggest it is a diagnostic feature of Menière's disease. Average age of onset was 42.59 years; this did not differ from males to females. Prevalence in females exceeded that in males by about 4:3. The disease was bilateral in 31.13%. Generally, those with better hearing thresholds at the first examination had less tendency to develop bilaterality. Age of onset was not significantly correlated with bilaterality.

Evaluation of biomarkers for occupational exposure to benzene

OBJECTIVE

To evaluate the relations between environmental benzene concentrations and various biomarkers of exposure to benzene.

METHODS

Analyses were carried out on environmental air, unmetabolised benzene in urine, trans, trans-muconic acid (ttMA), and three major phenolic metabolites of benzene; catechol, hydroquinone, and phenol, in two field studies on 64 workers exposed to benzene concentrations from 0.12 to 68 ppm, the time weighted average (TWA). Forty nonexposed subjects were also investigated.

RESULTS

Among the five urinary biomarkers studied, ttMA correlated best with environmental benzene concentration (correlation coefficient, r = 0.87). When urinary phenolic metabolites were compared with environmental benzene, hydroquinone correlated best with benzene in air. No correlation was found between unmetabolised benzene in urine and environmental benzene concentrations. The correlation coefficients for environmental benzene and end of shift catechol, hydroquinone, and phenol were 0.30, 0.70, and 0.66, respectively. Detailed analysis, however, suggests that urinary phenol was not a specific biomarker for exposure below 5 ppm. In contrast, ttMA and hydroquinone seemed to be specific and sensitive even at concentrations of below 1 ppm. Although unmetabolised benzene in urine showed good correlation with atmospheric benzene (r = 0.50, P < 0.05), data were insufficient to suggest that it is a useful biomarker for exposure to low concentrations of benzene. The results from the present study also showed that both ttMA and hydroquinone were able to differentiate the background level found in subjects not occupationally exposed and those exposed to less than 1 ppm of benzene. This suggests that these two biomarkers are useful indices for monitoring low concentrations of benzene. Furthermore, these two metabolites are known to be involved in bone marrow leukaemogenesis, their applications in biological monitoring could thus be important in risk assessment.

CONCLUSION

The good correlations between ttMA, hydroquinone, and atmospheric benzene, even at concentrations of less than 1 ppm, suggest that they are sensitive and specific biomarkers for benzene exposure.

Electrophysiological manifestations of the excitable gap of slow-fast AV nodal reentrant tachycardia demonstrated by single extrastimulation

BACKGROUND

Although AV nodal reentrant tachycardia (AVNRT) is a well-known rhythm disorder, its anatomic substrate and electrophysiological mechanism remain to be defined. Previously, the description of the excitable gap (EG) of AVNRT was based on electrical stimulation performed from sites remote from the reentrant circuit. In the present study, we characterized the EG of AVNRT by atrial extrastimulation close to the putative reentrant circuit in the AV junction.

METHODS AND RESULTS

In 16 patients (3 men, 13 women; mean age, 45 +/- 13 years) with inducible slow-fast AVNRT (mean cycle length, 353 +/- 52 ms), single extrastimuli with a 10-ms decrement in the premature coupling interval were delivered from the anterosuperior interatrial septum (fast pathway area) and the posteroinferior interatrial septum (slow pathway area) from late diastole until atrial refractoriness. An EG was considered present when resetting or termination of AVNRT was induced by single atrial extrastimulation. The study showed that the duration of the EG of AVNRT was wide, measuring 121 +/- 56 and 123 +/- 47 ms and occupying 33 +/- 11% and 34 +/- 9% of the tachycardia cycle length during single extrastimulation from the slow pathway area and the fast pathway area, respectively. The resetting pattern most commonly manifested as the sum of the coupling interval and the return cycle being less than a fully compensatory pause (two times the basic tachycardia cycle length). However, patterns equal to and greater than a fully compensatory pause were also observed. Of note, in 2 of the 16 patients, atrial extrastimulation from either the fast or slow pathway area also affected the preceding tachycardia cycle length (HH interval), indicating alteration of the anterograde input. In all patients, the curve derived from plotting the coupling interval of extrastimuli against the return cycle during resetting exhibited an "increasing" pattern. The mode of tachycardia termination usually occurred when the premature atrial impulse was orthodromically blocked in the anterograde slow pathway.

CONCLUSIONS

The EG of slow-fast AVNRT is relatively wide, as demonstrated by single atrial extrastimulation from the interatrial septum near the AV junction. Overall, the electrophysiological manifestations of the EG of AVNRT are very similar to those described in AV reciprocating tachycardia incorporating an accessory connection. These findings lend further support to the notion that, in humans, AVNRT involves a reentrant mechanism with a wide excitable gap.

Cellular immune responses in the pig uterus during pregnancy

In pigs, little is known about the role of the uterine immune system during pregnancy. Immunohistochemical studies were conducted using a panel of monoclonal antibodies to pig leukocytes on uterine tissues taken from gilts after fertile mating and at different stages of pregnancy. Acute inflammation in the endometrium in response to fertile mating which included marked changes in the tissue and immune cell components of the endometrium was observed. Throughout pregnancy the pig uterus contained a substantial population of leukocytes. MHC class II staining was prominent in the endometrium at all stages examined and included macrophages, dendritic and fibroblast-like cells, lymphocytes and the endothelial lining of many uterine blood vessels. The majority of lymphoid cells were CD2+, indicating the prevalence of T cells. In early pregnancy specific changes were seen in the tissue distribution of uterine immune cells. Following placentation distinct cellular changes in the local immune cell environment of the uterus were also observed despite the non-invasive nature of the pig placenta. There appears to be suppression and activation of various immune cell components in the uteri of pregnant pigs. This phenomenon is presumably in response to foetal or trophoblast antigens, suggesting that the local immune system is involved in the uterine response to pregnancy.

Localization of uridine 5'-diphosphate-glucuronosyltransferase in human liver injury

BACKGROUND/AIMS

Pharmacokinetic studies in patients with cirrhosis have shown a decreased clearance of drugs metabolized by cytochrome P450, whereas drugs metabolized by glucuronidation frequently have a normal elimination. The mechanism for the apparent preservation of glucuronidation has not been elucidated. The aim of this study was to examine the expression of uridine 5'-diphosphate-glucuronosyltransferase (UGT) in human liver injuries.

METHODS

UGT was measured by immunohistochemistry using a UGT polyclonal antibody, which was then compared with a representative isoform of cytochrome P450. Normal liver biopsy specimens (n = 8) and a spectrum of liver injury biopsy specimens (n = 47) were examined.

RESULTS

Compared with normal liver, increased staining for UGT in remaining hepatocytes was seen in liver damaged by chronic alcohol abuse, but the most intense immunoreactivity was observed in remaining and regenerative hepatocytes in specimens with cirrhosis. Primary biliary cirrhosis showed diffusely increased immunoreactivity. Other nonmalignant groups showed an increased staining relative to chronicity of liver disease. In contrast, in all liver injuries, cytochrome P450 staining was reduced as compared with controls.

CONCLUSIONS

Chronic liver damage results in increased UGT in remaining viable hepatocytes. Mechanisms may operate in liver injury to preserve expression of UGT in functional hepatocytes, and this may explain the preservation of glucuronidation in cirrhosis.

Numerical simulation of instantaneous backflow through central clearance of bileaflet mechanical heart valves at closure: shear stress and pressure fields within clearance

Instantaneous backflow through central clearance of bileaflet heart valves at the instant of closure is investigated. An Edwards-Duromedics valve in the mitral position is employed to measure the transient pressures near the entrance and exit region in an in vitro flow chamber. A region surrounding the clearance is modelled, and two-dimensional quasi-steady-state numerical simulations are performed, with the measured transient pressure difference across the clearance as a driving force for the flow. The results show that pressure difference several times larger than the driving pressure used to close the valve is established across the clearance for about 0.5 ms at the moment of closure. The resulting average wall shear stress is an order of magnitude larger than the turbulent Reynolds stresses reported distal to the valve during opening. A local jump in the shear stress distribution and fall in the pressure distribution are observed at the entrance region. Rounding of the corners in the channel entrance attenuates these spikes. The results of the study indicate that backflow through clearance at closure may be one reason for the haemolysis and thrombosis associated with mechanical heart valves, despite the short duration of the flow field.

Risk factors and predictors of outcome in an Australian cohort with hepatitis C virus infection

OBJECTIVES

To define demographic and epidemiological features of an Australian population with chronic hepatitis C virus (HCV) infection and determine predictors of histological and clinical outcome.

DESIGN

Cohort study.

PATIENTS AND SETTING

342 consecutive HCV antibody-positive patients referred to the liver clinic of a major metropolitan general hospital.

OUTCOME MEASURES

Demographic data, serial alanine aminotransferase (ALT) levels, full blood count for all patients. Percutaneous liver biopsy in 152 patients (44%).

RESULTS

51% of patients had previously used injecting drugs, 15% had received a blood transfusion and 27% had no definite percutaneous risk factor (sporadic group). The injecting drug users (IDUs) were younger and more likely to have been born in Australia. The sporadic group were older and frequently were born in Mediterranean or Asian countries. A history of excessive alcohol use was common, particularly among IDUs (60%). Of 152 patients who had a liver biopsy, 49 had cirrhosis and 103 had chronic hepatitis. Some patients with a normal ALT level had marked necro-inflammatory activity. On univariate analysis, the presence of cirrhosis correlated with older age (P < 0.0001), lack of an identifiable risk factor (P < 0.001) and birth in a Mediterranean or Asian country (P < 0.0001). On multivariate analysis, the only significant predictor of cirrhosis was age (P < 0.001). Among patients with an identifiable percutaneous risk factor, cirrhosis was seen at a median time of 18 years after first exposure to risk, compared with 13 years in patients with chronic hepatitis (P < 0.01). Patients with clinical evidence of portal hypertension were, on average, 15 years older than those with histological cirrhosis only (P < 0.01).

CONCLUSIONS

Injecting drug use is the major risk factor for chronic HCV infection in Australia. In patients with an identifiable risk factor, the most significant factor associated with a biopsy finding of cirrhosis is the time since first exposure to HCV.

p53 protein immunoreactivity in cancers of the gallbladder, extrahepatic bile ducts and ampulla of Vater

Immunohistochemical expression of the p53 protein was investigated in carcinoma of the gallbladder (n = 13), common bile duct (n = 7) and ampulla of Vater (n = 9) using the polyclonal, CM1, and monoclonal, DO7, antibodies (Novocastra). This was compared with cases of chronic cholecystitis (n = 11) and preneoplastic lesions of the gallbladder (n = 4) and ampulla (n = 3). Nuclear immunostaining for p53 protein was found only in the poorly differentiated adenocarcinomas of the gallbladder (n = 9) and were associated with a shorter patient survival period (median: 18.6 mths). The moderately differentiated adenocarcinomas (n = 4) did not show p53 immunostaining and were associated with a longer median survival period (26 mths). The gallbladder dysplasias and adenoma also had no p53 protein immunoreactivity. The common bile duct carcinomas did not stain for p53. Focal p53 immunoreactivity was present in only one (11%) of the cases of ampullary carcinoma and in one (9%) of chronic cholecystitis. In summary, increased p53 immunostaining was associated with reduced patient survival and found more frequently in poorly differentiated adenocarcinoma of the gallbladder but not in the better differentiated carcinoma, chronic cholecystitis or preneoplastic lesions of the gallbladder. The differences in p53 immunohistological expression between gallbladder, common bile duct and ampullary carcinomas justify further investigation into the molecular mechanisms responsible for their development.

Patterns of asymmetry do not change over the course of idiopathic parkinsonism: implications for pathogenesis

We investigated the asymmetry of focal deficits of bradykinesia in a cross-sectional study of 198 patients with idiopathic parkinsonism. We have analyzed the difference in Unified Parkinson's Disease Rating Scale (UPDRS) scores between the more and less affected sides in these patients, whose duration of symptoms ranged from 1 to 15 years. There was no significant change in the asymmetry or focality over this period; the deficit for each side progressed faster initially and then approached the normal age-related linear rate of decline. Previous studies indicate that there is an inverse linear relation between the UPDRS bradykinesia score and the nigral dopaminergic cell count. We infer that the rate of death of nigral dopaminergic neurons is predetermined from the time of onset of pathogenesis. The simplest explanation is that a causal event kills some cells and damages others so that they undergo premature death. This sequence of changes could be implemented through environmental (toxic or viral) damage to the genome. Several diverse sources of evidence support this concept.