Immunohistochemical detection of bcl-2 protein in liver lesions: bcl-2 protein is expressed in hepatocellular carcinomas but not in liver cell dysplasia

A proto-oncogene, bcl-2, encodes a protein that inhibits programmed cell death (apoptosis) and may play a role in cell and tissue differentiation. As bcl-2 appears to be involved in the turn-over of stem or precursor cells, it is thought to be operational in carcinogenesis pathways. However, apart from certain lymphomas, only limited data are available on the frequency of its expression in solid tumors. Immunohistochemical analysis with an antibody specific for bcl-2 protein was used to detect the protein in hepatocellular carcinomas and in one of the putative precursor lesions, liver cell dysplasia. We detected bcl-2 protein in 5 of 37 hepatocellular carcinomas. Immunoreactivity was not related to type, grade, or extent of PCNA staining of the tumours. No bcl-2 protein staining was observed in three types of liver cell dysplasia. Thus, bcl-2 is abnormally expressed in some hepatocellular carcinomas but not in potential tumour precursor cells.

[Congenital lower lip sinuses]

Congenital lower sinuses are rare and are found often in association with cleft lip and/or palate, named Van der Woude syndrome. Although the condition per se does not always require surgical attention, its genetic character is interesting. Four cases of congenital sinuses are described and recent literature is reviewed.

An unusual pattern of lymph node involvement in mycosis fungoides simulating neoplastic follicles

We describe an unusual pattern of lymph node involvement in a case of mycosis fungoides. The neoplastic proliferation formed pale nodules composed of small, irregular lymphoid cells, features that, on routine paraffin sections, suggested neoplastic follicles and a B-cell phenotype. The correct diagnosis was established by immunohistochemical studies that demonstrated a T-cell phenotype. Polymerase chain reaction for rearrangement of the T-cell receptor gamma gene confirmed that the proliferation was monoclonal. This case demonstrates that both architectural pattern and cytologic features may be unreliable in predicting immunologic phenotype. Immunologic marker studies and careful attention to the clinical history are vital to classify lymphoproliferative disorders correctly.

Immunohistochemical analysis of p53 protein overexpression in liver cell dysplasia and in hepatocellular carcinoma

We analysed p53 protein immunoreactivity in hepatocellular carcinomas (HCCs) and in liver cell dysplasia (LCD) of patients from an area in Northern China, using five anti-p53 protein antibodies recognizing different epitopes of the protein. In HCCs, the overall prevalence of p53 protein immunoreactivity was 78.3%. However, prevalence was strongly influenced by the type of antibody used, ranging from 67.5% for antibody PAb-1801 to only 10.8% for antibodies PAb-421 and DO-7. p53 protein immunoreactivity was not related to type or grade of HCC. In contrast to former reports, p53 protein staining was restricted to nuclei only when using the CM-1 antibody, whereas two other antibodies yielded both, nuclear and cytoplasmic or membrane staining, and no nuclear staining was observed with antibodies PAb-421 and DO-7, the latter two, however, demonstrating cytoplasmic and membrane staining. For LCD, three subtypes were morphologically and karyometrically defined. Nuclei of some LCD cells were p53 immunoreactive, but positivity was restricted to the small cell variant of LCD. Positivity was different for cirrhosis with or without associated HCC, amounting to 18.9% in the former and 39.4% in the latter. Interestingly, p53 protein immunoreactivity also occurred in a set of small hepatocytes not showing the typical feature of LCD and therefore classified as simple regenerating liver cells.

Design and synthesis of RNA-specific groove-binding cations: implications for antiviral drug design

As as initial step in the design of structure-specific RNA-interactive molecules as potential antiviral agents, we have focused on the synthesis of molecules that exhibit strong and preferential binding to duplex RNA. A series of polycationic ligands have been synthesized, and the degree of preferential binding to RNA has initially been determined by thermal denaturation (delta Tm) with both RNA [poly(A).poly(U)] and DNA [poly(dA).poly(dT)] polymers at a variety of pH values. Seven compounds from the series exhibit a substantial degree of RNA-selective binding. The relatively high delta Tm values obtained suggest a specific mode of interaction between these ligands and the RNA helix. By contrast, the much lower delta Tm values with poly(dA).poly(dT) DNA reflect a more nonspecific interaction mode. A viscometric titration study with poly(A).poly(U) confirms that they do not bind by intercalation. The results, combined with the known structure and electronegative potential of duplex RNA, suggest that these molecules bind in the major groove via specific electrostatic and/or hydrogen-bonded interactions.

[The alteration of histidase catalytic activity and the expression of the enzyme protein in rat primary hepatomas]

The catalytic activity of histidase and the expression of the enzyme protein were investigated in rat hepatomas induced by diethylnitrosamine. The results indicated that the activities of histidase in the hepatomas were significantly diminished as compared with normal rat livers (P < 0.01). Western blot analysis revealed that enzyme protein levels in hepatomas were markedly reduced. It is thus inferred that some factors which control expression of histidase protein may be altered during carcinogenesis. These findings lay a foundation for studying the relationship between the regulation and expression of the histidase gene and hepato carcinogenesis.

Large-scale purification of human aspartylglucosaminidase: utilization of exceptional sodium dodecyl sulfate resistance

Deficiency of human aspartylglucosaminidase (AGA, glycosylasparaginase, EC 3.5.1.26), a lysosomal amidase, results in the lysosomal storage disease aspartylglucosaminuria (AGU). This disorder is most prevalent in the genetically isolated Finnish population. To facilitate the detailed analysis of this important enzyme, which functions in the final degradation step of glycoproteins, we developed a novel purification method which makes possible a simple five-step 5000-fold purification to apparent homogeneity of human aspartylglucosaminidase from leukocytes. This purification procedure takes advantage of the remarkable SDS resistance of aspartylglucosaminidase as SDS-sensitive proteins aggregate preferentially at low (NH4)2SO4 concentrations in the presence of SDS. This new method should be applicable to the isolation of other SDS-resistant enzymes, e.g., superoxide dismutase. The homogeneous enzyme preparation exhibited a previously unreported fully denatured 19-kDa form of the alpha-subunit of aspartylglucosaminidase on SDS-polyacrylamide gel electrophoresis as a consequence of complete coating by SDS.

Effects of oxygen free radicals and scavengers on the cardiac extracellular collagen matrix during ischemia-reperfusion

OBJECTIVE

Collagen is lysed early during ischemia-reperfusion, but whether this is due to ischemia or reperfusion injury is not known. The effect of oxygen free radicals and free radical scavengers on left ventricular hemodynamics, myocardial morphology and collagen content were studied in an isolated, Langendorff-perfused rat heart model of regional ischemia-reperfusion.

METHODS

All hearts received left anterior descending coronary artery ischemia for 20 mins. Group 1 had ischemia only; group 2 had ischemia followed by reperfusion with oxygenated Krebs-Henseleit buffer for 20 mins; group 3 had oxygen free radicals generated by hypoxanthine and xanthine oxidase during reperfusion; group 4 had free radical scavengers with superoxide dismutase plus catalase; group 5 had both oxygen free radicals and free radical scavengers during reperfusion.

RESULTS

Left ventricular developed pressure decreased significantly in group 3 during ischemia followed by reperfusion (58 +/- 3.1 mmHg versus 42 +/- 2.4 mmHg, P = 0.004), but did not change significantly in any of the other groups. Necrosis score on pathology was highest in group 3; this score also was higher than that in group 5 with free radical scavengers added (3.0 +/- 0.3 versus 2.0 +/- 0.4, P = 0.07) and higher than that of group 2 with reperfusion with buffer only (3.0 +/- 0.3 versus 1.4 +/- 0.5, P < 0.05). Collagen content decreased significantly compared with control in group 3 only with ischemia followed by reperfusion with the addition of oxygen free radicals (18.4 +/- 1.5 versus 11.9 +/- 1.7 g/mg protein, P < 0.05). The addition of free radical scavengers in group 5 mainly attenuated the collagen loss. Scanning electron microscopy revealed profound structural changes of the extracellular collagen matrix in numerous regions of 'stunning' independent of tissue necrosis.

CONCLUSIONS

We conclude that: first, oxygen free radicals trigger significant collagen damage and left ventricular dysfunction during reperfusion; second, these changes extend beyond the ischemic damage alone; and third, free radical scavengers can effectively limit oxygen free radical-induced collagen loss and left ventricular dysfunction.

Synthesis of dicationic diaryltriazines nucleic acid binding agents

- The synthesis of 2,4-bis[4-(4,5-dihydro-1H-imidazol-2-yl)phenyl]-1,3,5-triazine 6a and 2,4-bis[4-(1,4,5,6-tetrahydropyrimidin-2-yl)phenyl]-1,3,5-triazine 6b in 3 steps from either 4-bromobenzamidine or 4-(carbamoyl)benzamidine is reported. The synthesis of 4,6-bis[4-(4,5-dihydro-1H-imidazol-2-yl)phenyl]-2-dimethylamino-1,3,5-triazine 9a and 4,6-bis[4-(1,4,5,6-tetrahydropyrimidin-2-yl)phenyl]-2-dimethylamino-1,3,5-triazine 9b in 2 steps from 1,4-dicyanobenzene is also described. The compounds 6b and 9b bind strongly to DNA model sequences and inhibit topoisomerase II from 2 microbial sources. Compounds 6a and 9a bind to both DNA and RNA model sequences whereas 6b and 9b essentially do not bind to the RNA model.

Three types of liver cell dysplasia (LCD) in small cirrhotic nodules are distinguishable by karyometry and PCNA labelling, and their features resemble distinct grades of hepatocellular carcinoma

We have studied the occurrence and specific features of liver cell dysplasia (LCD) in Chinese patients showing liver cirrhosis with or without hepatocellular carcinoma (HCC). Three types of LCD (SLCD, LLCDo, LLCDe) were morphologically defined, and these types were further analyzed using karyometry, estimation of nucleic acid content and density, and PCNA immunostaining. Features found for three types of LCD were compared with those of normal hepatocytes (NLC), simple regenerating hepatocytes (SRLC), and cells of HCCs covering different grades. The results show that 1) karyometry and nucleic acid parameters allow an objective separation of LCD types both from NLC and SRLC; 2) karyometric features of LLCDe are most close to those of highly differentiated HCCs, whereas nuclear size and chromatin composition of SLCD closely reflect those of poorly differentiated HCCs; 3) the frequency of LCD clusters was higher in cirrhotic livers carrying HCC, being about double for all three LCD types; 4) the highest PCNA labelling occurred in the small cell group of LCD (SLCD), still, however, being smaller than that of simple regenerating hepatocytes. Based on these findings it is suggested that, similar to atypical adenomatous hyperplasia, LCDs of distinct morphotypes may represent precursor lesions for HCC, and some cellular forms may mimick cell types known to occur in experimental carcinogenesis.

The interaction of substituted 2-phenylquinoline intercalators with poly(A).poly(U): classical and threading intercalation modes with RNA

The interaction of a series of 2-phenylquinoline derivatives with RNA was investigated by means of viscometric, pKa, spectroscopic, binding, Tm, and kinetic methods. Compounds 1, 2, and 3 have a piperazyl substituent at the para, meta, or ortho position, respectively, while 4 has an unsubstituted phenyl ring. The pKa results suggest that 1 has three charges, 2 and 3 have more than two charges, and 4 has two charges at pH 6.2. Spectroscopic and Tm results indicate that 1 binds more strongly to RNA than 2-4. Kinetic and modeling results indicate that 1 is a threading intercalator while 2 and 4 are classical intercalators. All experimental results indicate that 3, which has a large twist between the phenyl and quinoline rings, binds weakly with RNA.

Tracing B cell development in human germinal centres by molecular analysis of single cells picked from histological sections

Germinal centres are areas of intense B lymphocyte proliferation inside primary B cell follicles in spleen and lymph nodes. Rearranged V genes from single human B cells, isolated from histological sections of two such structures by micromanipulation, were amplified and sequenced. Cells from the follicular mantle were clonally diverse and largely expressed germline V genes. Germinal centres were dominated by a few large B cell clones dispersed throughout these structures and exhibiting intraclonal diversity by ongoing somatic hypermutation. Pronounced counterselection of replacement mutations seen in one of the germinal centres may indicate a late phase of the germinal centre reaction. A polyclonal population of activated B cells expressing unmutated antibodies in the dark zone of the other germinal centre may represent the initial founder cells.

Modulated excitation of singly ligated carboxyhemoglobin

We have extended the method of modulated excitation, a small perturbation kinetic method, to study ligand binding and conformational change of hemoglobin tetramers with a single ligand bound. To restrict the excitation to the first ligand, only 1% of the hemes have bound CO, and the remainder are kept unliganded. A detailed theory is presented which agrees well with the experimental observations. This method of observing ligand recombination also provides a novel and simple method for determination of hemoglobin concentration. Additional relaxation processes are also observed. By fitting independently determined spectra to the spectra associated with the relaxations, these processes are assigned as thermal excitation and thermally driven protonation/deprotonation reactions. These added relaxations arise from the deoxy-Hb portion of the samples, and demonstrate that modulated excitation can be used effectively for temperature perturbation in the absence of photodissociation. The spectra observed are not well described by the spectra of allosteric change, however, and we conclude that there is no significant mixing of quaternary states at the first ligation step. In an appendix we present a derivation of the particular features seen in thermally modulated protonation reactions.

Differential downregulation of beta 2-adrenergic receptors in tissue compartments of rat heart is not altered by sympathetic denervation

With agonist stimulation, cardiac beta 2-adrenergic receptors (beta 2ARs) are downregulated to a much greater extent than are beta 1ARs. It has been hypothesized that this effect is due to sympathetic innervation inhibiting the downregulation of beta 1ARs. To test this hypothesis, the technique of coverslip autoradiography was used to localize and quantify beta 1AR and beta 2AR subtypes in tissue compartments of the heart in rats subjected to sympathetic denervation by two intravenous injections of 6-hydroxydopamine (50 mg/kg per dose). After denervation, the rats were infused with L-isoproterenol (400 micrograms.kg-1 x h-1 for 7 days) or vehicle (0.001N HCI) by implantation of osmotic minipumps. Sections were incubated with 70 pmol/L of the beta AR antagonist [125I]iodocyanopindolol (ICYP) alone or in the presence of 5 mumol/L DL-propranolol or 5 x 10(-7) mol/L CGP 20712A (a beta 1AR antagonist). Binding of ICYP to sections of rat hearts was saturable and stereoselective and was displaced by beta AR agonists with the rank order of potency expected for beta ARs. There was an 89% reduction in catecholamine concentration in rat ventricles after 1 week of 6-hydroxydopamine treatment, before implantation of the minipumps. Chronic infusion of isoproterenol induced significant downregulation (63% to 74%) of beta 2ARs in atrial and ventricular myocytes, coronary arterioles, and connective tissue but no change in beta 1ARs in these regions in rats with intact sympathetic innervation. Similar changes were seen in denervated animals. There was a marked reduction in beta 2ARs but small insignificant decreases in beta 1ARs, despite the fact that in the denervated animals there was upregulation of beta 1ARs in atrial and ventricular myocytes (approximately 25%). Our study suggests that beta 1ARs in the heart are not significantly downregulated by chronic agonist exposure and that this is unrelated to sympathetic innervation. The underlying mechanism of preferential regulation of beta AR subtypes remains to be elucidated but may be related to differences in the molecular structure between beta 1ARs and beta 2ARs.

"Neuroendocrine" differentiation in hepatocellular carcinomas (HCCs): immunohistochemical reactivity is related to distinct tumor cell types, but not to tumor grade

We have analyzed neuroendocrine differentiation (ND) in hepatocellular carcinomas (HCCs) of fifty patients. It turned out that ND is frequent in HCCs, and that it is not restricted to fibrolamellar hepatocellular carcinoma (FL-HCC). Multiexpression is seen in a quarter of the cases, and marker coexpression may occur within the same tumor cell. ND predominates in trabecular and mixed HCCs, but does not appear to be related to grade. Most positive cases showed a hepatocyte-like cell morphology, frequently associated with bile formation. It thus appears that the HCC cell type most likely to show ND is a hepatocyte-like one, i.e. differentiated cell, frequently polarized and producing bile, rather than a small and poorly-differentiated cell. Possible pathogenic mechanisms leading to ND in HCCs are briefly discussed.

Two-dimensional scanning laser slope gauge: measurements of ocean-ripple structures

A compact, two-dimensional scanning laser slope gauge has been developed for measuring ocean ripples, leading to the determination of their directional slope spectrum in the wavelength range of 4.5-81 mm. A telecentric scanning mechanism is used to enhance the dynamic range of slope measurements and to eliminate constraints caused by water-surface undulations associated with long waves. Successful laboratory tests and field trials have been performed; sample results are provided.

Detection of clonal B cell populations in paraffin-embedded tissues by polymerase chain reaction

A method was established to detect clonal B cell populations in frozen and paraffin-embedded tissues. The method is based on the polymerase chain reaction amplification of rearranged VH and V kappa genes using V gene family-specific primers. Monoclonal B cell populations could be detected in peripheral blood lymphocyte DNA in all 16 cases of B-CLL and immunocytoma investigated and in 8 of 10 cases of B cell non-Hodgkin's lymphoma using frozen and paraffin sections. The amplification of V kappa rearrangements in addition to the VH amplification is a useful tool to verify the results of the heavy chain rearrangement and to detect proliferation of a B cell clone in cases in which no VH product was obtained. In spite of the degradation of DNA in paraffin-embedded tissues, we were able to find amplified polymerase chain reaction products of about 350 bp length in 8 of 10 cases analyzed. The method presented here may be helpful in routine diagnosis of B cell non-Hodgkin's lymphoma using frozen or paraffin-embedded specimens.

Post-ischaemic cardiac dilatation and remodelling: reperfusion injury of the interstitium

Cardiac size and geometry have an important influence on clinical prognosis in heart disease. The cardiac interstitium would appear to play a major role in modulating muscle configuration after ischaemic insults. Ischaemic reperfusion injury of the heart should not be viewed as confined to the myocyte compartment. There are major events occurring in the interstitial compartment which could ultimately determine the long-term configuration and topography of the heart. Thus, permanent plastic changes in cardiac dimensions appear to evolve after initial alterations in the collagen matrix. The physiological, cellular, biochemical, and molecular considerations in the cardiac interstitium are quite different from those of the myocyte compartment. Accordingly, therapeutic interventions to modulate cardiac geometry and remodelling may differ.

Evaluation of a nutrition education activity for medical students in China

In China, where cancers and cardiovascular disease are the major causes of morbidity and mortality, an important role for preventive medicine has emerged. Therefore, preparing China's medical students to tackle contemporary health problems requires attention to nutrition and health promotion in the medical curriculum. To evaluate the effectiveness of a nutrition education activity for medical students, a two-group pre-test/post-test nutrition education program was conducted in a medical university in south-western China (n=300 per group). Students in another south-western Chinese medical university served as controls (n= 150 per group). Special features of the intervention were: (1) nutrition education materials developed from (a) the results of a pre-test survey of medical students and (b) discussions with medical students, faculty, and physicians; and (2) a multi-channel delivery, which included a classroom lecture-discussion; a nutrition knowledge competition; a handout providing a day's dietary allotment; campus radio and movie theatre announcements, and posters. Analysis of variance, chi-square, and t-tests showed a significant increase (P<0.05) in nutrition knowledge, but not in nutrition attitude score. The final nutrition knowledge and attitude scores were also found to be related to the students' increased exposure to the various channels (P<0.001). Also observed was an increase in the consumption of soybean and dairy products (P<0.05). It is concluded that the method is a useful and practical model for designing and developing student nutrition education activities in China, as well as demonstrating nutrition and health education methods among the medical university community.

[Effects of epidermal growth factor on growth and differentiation of rat granulosa cells]

It was known that epidermal growth factor (EGF) plays an important role in the regulation of reproduction. The present study was undertaken to investigate the effect of EGF on the proliferation and differentiation of cultured rat granulosa cells. The results showed that EGF inhibited the 3H-TdR incorporation into DNA of granulosa cells, while the progesterone production was increased due to enhanced 3 beta-HSD activity. Radioreceptor assay (RRA) suggested that there were specific receptors for EGF on the granulosa cell with a Kd of 1.83 +/- 0.30 x 10(-8) mol/L and a Bmax of 1.75 +/- 0.29 x 10(4) sites/cell. Using method of immunohistochemistry, no EGF-like immunoreactivity was found in the granulosa cells at different age or different estrous cycle, but in the theca folliculi, interstitium and corpus luteum. These results suggest that EGF can regulate the growth and differentiation of the granulosa cells in the course of maturation of the folliculi and granulosa cells.

Allosteric kinetics and equilibria of triligated, cross-linked hemoglobin

Using modulated excitation, we have measured the forward and reverse rates of the allosteric transition between relaxed (R) and tense (T) quaternary structures for triply ligated hemoglobin (Hb), cross-linked between the alpha chains at Lys 99. Oxygen, carbon monoxide, and water were used as ligands and were studied in phosphate and low Cl- bis-Tris buffers at neutral pH. Since the cross-link prohibits disproportionation, triply ligated aquomet Hb species with ferrous beta chains were specifically isolated by isoelectric focusing. Modulated excitation provides rate pairs and therefore gives equilibrium constants between quaternary structures. To coordinate with that information, oxygen binding curves of fully ferrous and tri-aquomet Hb were also measured. L3, the equilibrium constant between three liganded R and T structures, is determined by modulated excitation to be of order unity for O2 or CO (1.1 to 1.5 for 3O2 and 0.7 for 3CO bound), while with three aquomet subunits it is much greater (> or = 23). R-->T conversion rates are similar to those found for HbA, with weak sensitivity to changes in L3. The L3 values from HbXL O2 were used to obtain a unique allosteric decomposition of the ferrous O2 binding curve in terms of KT, KR, and L3. From these values and the O2 binding curve of tri-aquomet HbXL, L3 was calculated to be 2.7 for the tri-aquomet derivative. Consistency in L3 values between equilibrium and modulated excitation data for tri-aquomet-HbXL can be achieved if the equilibrium constant for O2 binding to the alpha chains is six times lower than that for binding to the beta chains in the R state, while the cooperative properties remain homogeneous. The results are in quantitative agreement with other studies, and suggest that the principal effect of the cross-link is to decrease the R state and T state affinity of the alpha subunits with almost no change in the affinity of the beta subunits, leaving the allosteric parameters L and c unchanged.