Role of stem cells and gap junctional intercellular communication in human carcinogenesis

Epidemiological data, experimental animal bioassays, studies of in vitro neoplastic transformation, and molecular oncology studies have implicated a multistage, multimechanism process in human carcinogenesis. From animal carcinogenesis studies, the operational concept of a single normal cell being irreversibly altered during the first step in carcinogenesis is called initiation. The subsequent interruptible or reversible clonal expansion of these initiated cells by non-cytotoxic mitogenic stimuli, compensatory hyperplasia due to cell death by necrosis, or inhibition of apoptosis is referred to as the promotion phase. Last, when one of these clonally expanded, initiated cells acquires sufficient genetic/epigenetic alterations to become neoplastically transformed and acquire the phenotypes of promoter independence, invasiveness and metastasis, it is referred to as the progression step of carcinogenesis. This report hypothesizes that the single normal cell that is initiated is a pluripotent stem cell. By assuming that the normal pluripotent stem cell is immortal and becomes mortal when induced to terminally differentiate, initiation would be viewed as the irreversible process by which a stable alteration in a finite number of proto-oncogenes and/or tumor suppressor genes could block terminal differentiation or "mortalization". Promotion would involve the reversible inhibition of gap junctional intercellular communication (GJIC) and while progression occurs with the stable down-regulation of GJIC.

Antigenic specificity of anti-neutrophil cytoplasmic antibody

PURPOSE

To determine the antigens recognized by sera containing classic anti-neutrophil cytoplasmic antibodies (c-ANCAs) and perinuclear anti-neutrophil cytoplasmic antibodies (p-ANCAs).

METHODS

A total of 160 serum samples (all from a reference laboratory) that were originally collected from different clinics for ANCA tests were examined for c-ANCA and p-ANCA by indirect immunofluorescence (IIF). All positive sera were further tested for reactivity to proteinase 3 (PR3), myeloperoxidase (MPO), lactoferrin (LF), and lysozyme (LZ) by enzyme-linked immunosorbent assay (ELISA). In addition, sera from 110 patients with systemic lupus erythematosus (SLE), 51 patients with rheumatoid arthritis (RA), and 40 healthy subjects were also tested for reactivity to these antigens.

RESULTS

HF detected ANCA in 81 (51%) of the 160 clinical serum samples. Of these 81 serum samples, 21 (26%) contained c-ANCA and 60 (74%) contained p-ANCA. P-ANCA was more commonly found in antinuclear antibody (ANA)-positive sera than in ANA-negative sera (p < 0.01). Of the 21 serum samples positive for c-ANCA, 12 (57%) reacted to PR3, four (19%) to LF, four (19%) to LZ, and three (14%) to MPO on ELISA. By contrast, of the 60 sera positive for p-ANCA, 15 (25%) reacted to MPO, 13 (22%) to PR3, eight (13%) to LF, and four (7%) to LZ. The prevalence of ANCA specificities in serum samples from SLE patients were as follows: anti-PR3, 0%; anti-MPO, 1%; anti-LF, 27%; and anti-LZ, 29%. The prevalence of ANCA specificities in serum samples from RA patients were as follows: anti-PR3, 6%; anti-MPO, 2%; anti-LF, 8%; anti-LZ, 4%.

CONCLUSION

Sera positive for c-ANCA and p-ANCA reacted to diverse cytoplasmic antigens from neutrophils. P-ANCA was found in 55% of ANA-positive serum samples. LF and LZ were most commonly found in serum samples from patients with SLE.

Leukocyte chemosensory migration on vascular prosthetic biomaterial is mediated by an integrin beta2 receptor chain

The ability of adherent activated leukocytes to migrate on implanted prosthetic biomaterial surfaces may be an early rate-limiting step in eliminating periprosthetic infection. The goal of this study was to explore the molecular mechanism governing leukocyte migration on the implantable cardiovascular prosthetic biomaterial, expanded polytetrafluoroethylene (ePTFE), in response to stimulation by the soluble chemokine, N-formyl-methionyl-leucyl-phenylalanine (fMLP). We used a population level migration assay to study the migration of polymorphonuclear leukocytes (PMN) on ePTFE, overlaid by a gelatin/agar composite. A theoretical random walk model was applied to describe fMLP-induced PMN migration on ePTFE in terms of an objective random cell migration coefficient, mu. Our results show that following stimulation with 0-10(-7) M fMLP, the value of mu ranged from 5.43 x 10(-9) to 1.08 x 10(-7) cm2/s, with a maximum value obtained at 10(-8) M fMLP. We probed the expression levels of various beta2 integrin receptor subunits and their contribution to the migratory function of ePTFE-adherent PMN over a wide range of fMLP concentration. We found that the expression of the integrin beta-chain, CD18, was also maximized at 10(-8) M fMLP, along with only slight changes in the expression of integrin alpha-chains (CD11a,b,c). We report that treatment with antibodies against either beta or combined alpha chains, but not individual alpha chains, inhibited PMN attachment to ePTFE at 10(-8) M fMLP, suggesting the likely role of combined beta2 receptor subunits in early adhesion events following stimulation. However, treatment with only anti-CD18 significantly lowered PMN migration on ePTFE (mu = 5.98 x 10(-9) cm2/s), and this degree of inhibition was much greater than that elicited by the combined treatment with antibodies recognizing all possible alpha-chains. Overall, we conclude that migratory behavior of chemokinetically stimulated PMN on ePTFE is mediated by the integrin beta chain pool, and is only weakly regulated by the integrin alpha chain.

Immunophenotypic profile of myeloid cells in granulocytic sarcoma by immunohistochemistry. Correlation with blast differentiation in bone marrow

The present study was designed to evaluate the lineage differentiation (particularly monocytic differentiation) of immature myeloid cells in granulocytic sarcoma (GS) by immunohistochemistry and correlate the results with lineage differentiation of blasts in the bone marrow and to determine the degree of maturation of the infiltrating myeloid cells in GS by immunohistochemistry using CD34 and HLA-DR. Immunohistochemical stains were performed on paraffin-embedded tissue from 17 GS lesions with lineage-associated markers: myeloperoxidase, CD68 (KP1), CD68 (PG-Ml), glycophorin A, factor VIII, and CD56; and with markers for blasts and immature myeloid cells: CD34 and HLA-DR. Our results show that positive staining with PG-M1, but not KP1, suggests monocytic differentiation of myeloid cells in GS and correlates with the monocytic differentiation of blasts in the bone marrow. Expression of CD56 is frequent in GS, especially when the marrow blasts have monocytic differentiation, and should not be interpreted as a primary natural-killer cell process. The immature myeloid cells in GS are frequently HLA-DR positive. However, CD34 positivity of the immature myeloid cells is relatively uncommon, except in cases with underlying myelodysplastic syndrome or chronic myelogenous leukemia.

Coyotes (Canis latrans) as the reservoir for a human pathogenic Bartonella sp.: molecular epidemiology of Bartonella vinsonii subsp. berkhoffii infection in coyotes from central coastal California

Bartonella vinsonii subsp. berkhoffii was originally isolated from a dog suffering infectious endocarditis and was recently identified as a zoonotic agent causing human endocarditis. Following the coyote bite of a child who developed clinical signs compatible with Bartonella infection in Santa Clara County, Calif., this epidemiological study was conducted. Among 109 coyotes (Canis latrans) from central coastal California, 31 animals (28%) were found to be bacteremic with B. vinsonii subsp. berkhoffii and 83 animals (76%) had B. vinsonii subsp. berkhoffii antibodies. These findings suggest these animals could be the wildlife reservoir of B. vinsonii subsp. berkhoffii. PCR-restriction fragment length polymorphism (PCR-RFLP) analysis of the gltA and 16S rRNA genes for these 31 isolates yielded similar profiles that were identical to those of B. vinsonii subsp. berkhoffii. Partial sequencing of the gltA and 16S rRNA genes, respectively, indicated 99.5 and 100% homology between the coyote isolate and B. vinsonii subsp. berkhoffii (ATCC 51672). PCR-RFLP analysis of the 16S-23S intergenic spacer region showed the existence of two different strain profiles, as has been reported in dogs. Six (19%) of 31 Bartonella bacteremic coyotes exhibited the strain profile that was identified in the type strain of a canine endocarditis case (B. vinsonii subsp. berkhoffii ATCC 51672). The other 25 bacteremic coyotes were infected with a strain that was similar to the strains isolated from healthy dogs. Based on whole bacterial genome analysis by pulsed-field gel electrophoresis (PFGE) with SmaI restriction endonuclease, there was more diversity in fingerprints for the coyote isolates, which had at least 10 major variants compared to the two variants described for domestic dog isolates from the eastern United States. By PFGE analysis, three Bartonella bacteremic coyotes were infected by a strain identical to the one isolated from three healthy dog carriers. Further studies are necessary to elucidate the mode of transmission of B. vinsonii subsp. berkhoffii, especially to identify potential vectors, and to determine how humans become infected.

Methods of cytologic smear preparation and fixation. Effect on the immunoreactivity of commonly used anticytokeratin antibody AE1/AE3

OBJECTIVE

To evaluate the effect of fixation and methods of cytologic smear preparation on the immunoreactivity of commonly used anticytokeratin antibody AE1/AE3.

STUDY DESIGN

Scrape cytology smears and formalin-fixed, paraffin-embedded tissue sections (FPTS) of 20 unfixed, fresh specimens submitted for intraoperative consultation were studied by the immunoperoxidase method. In addition to the morphologic examination, the smears and FPTS were evaluated for intensity and proportion scores. For each specimen, two scrape cytology smears were wet fixed in 95% ethanol, and 12 smears were air dried without fixation. Air-dried smears were either postfixed after rehydration in saline or fixed directly without rehydration by one of the three fixatives: alcoholic formalin, 95% ethanol with 5% acetic acid or 95% ethanol.

RESULTS

Both intensity and proportion scores were higher with rehydrated, air-dried smears as compared to those without rehydration and were comparable to those with wet-fixed smears and FPTS. In the rehydrated group, the optimum results were achieved when the smears were postfixed with alcoholic formalin.

CONCLUSION

The method of preparation and fixation had variable effects on the immunoreactivity of anticytokeratin antibody AE1/AE3. The optimum results were achieved with saline-rehydrated, air-dried smears post-fixed in alcoholic formalin. To evaluate the role of inter-sample variation, further, larger studies are recommended on this and other antibodies before applying them to different types of cytologic smears.

Canal-wall-down tympanoplasty with mastoidectomy for advanced cholesteatoma

OBJECTIVE

The objective of this study was to review 8.5 years of the senior author's experience with canal-wall-down mastoid surgery for extensive cholesteatoma with high-grade atelectasis and severely destructed ossicles.

DESIGN

A retrospective review was conducted.

SETTING

The setting was a tertiary care medical centre.

METHODS

Available records consulted included 104 canal-wall-down mastoidectomy for advanced-stage cholesteatomas between July 1984 and December 1992.

MAIN OUTCOME MEASURES

Recurrence, hearing results, and dry ear rate were analyzed.

RESULTS

The recurrence rate was 4 of 104 (3.8%), and 9.6% of subjects suffered from recurrent otorrhea. Thirty-seven of 104 (35.6%) achieved the closure of air-bone gap within 20 dB. The availability of stapes suprastructure influenced the postoperative hearing level significantly (p < .001).

CONCLUSION

Even in treating advanced cholesteatoma, canal-wall-down mastoidectomy provides a low recurrence rate, establishes a high dry ear rate, and preserves adequate hearing when the stapes suprastructure is available for reconstruction.

Effect of electromagnetic field exposure on chemically induced differentiation of friend erythroleukemia cells

Whether exposure of humans to extremely low frequency electromagnetic fields (ELF-EMF) can cause cancer is controversial and therefore needs further research. We used a Friend erythroleukemia cell line that can be chemically induced to differentiate to determine whether ELF-EMF could alter proliferation and differentiation in these cells in a manner similar to that of a chemical tumor promoter. Exposure of this cell line to 60 Hz ELF-EMF resulted in a dose dependent inhibition of differentiation, with maximal inhibition peaking at 40% and 40 mG (4 microT). ELF-EMF at 10 mG (1.0 microT) and 25 mG (2.5 microT) inhibited differentiation at 0 and 20%, respectively. ELF-EMF at 1.0 (100) and 10.0 G (1,000 microT) stimulated cell proliferation 50% above the sham-treated cells. The activity of telomerase, a marker of undifferentiated cells, decreased 100[times] when the cells were induced to differentiate under sham conditions, but when the cells were exposed to 0.5 G (50 microT) there was only a 10[times] decrease. In summary, ELF-EMF can partially block the differentiation of Friend erythroleukemia cells, and this results in a larger population of cells remaining in the undifferentiated, proliferative state, which is similar to the published results of Friend erythroleukemia cells treated with chemical-tumor promoters.

Monocyte-derived CD1a+ and CD1a- dendritic cell subsets differ in their cytokine production profiles, susceptibilities to transfection, and capacities to direct Th cell differentiation

We describe a phenotypically and functionally novel monocyte-derived dendritic cell (DC) subset, designated mDC2, that lacks IL-12 synthesis, produces high levels of IL-10, and directs differentiation of Th0/Th2 cells. Like conventional monocyte-derived DC, designated mDC1, mDC2 expressed high levels of CD11c, CD40, CD80, CD86, and MHC class II molecules. However, in contrast to mDC1, mDC2 lacked expression of CD1a, suggesting an association between cytokine production profile and CD1a expression in DC. mDC2 could be matured into CD83+ DC cells in the presence of anti-CD40 mAbs and LPS plus IFN-gamma, but they remained CD1a- and lacked IL-12 production even upon maturation. The lack of IL-12 and CD1a expression by mDC2 did not affect their APC capacity, because mDC2 stimulated MLR to a similar degree as mDC1. However, while mDC1 strongly favored Th1 differentiation, mDC2 directed differentiation of Th0/Th2 cells when cocultured with purified human peripheral blood T cells, further indicating functional differences between mDC1 and mDC2. Interestingly, the transfection efficiency of mDC2 with plasmid DNA vectors was significantly higher than that of mDC1, and therefore mDC2 may provide improved means to manipulate Ag-specific T cell responses after transfection ex vivo. Taken together, these data indicate that peripheral blood monocytes have the capacity to differentiate into DC subsets with different cytokine production profiles, which is associated with altered capacity to direct Th cell differentiation.

On-line monitoring trihalomethanes in chlorinated water by membrane introduction-fast gas chromatography mass-spectrometry

An analytical method based on membrane introduction and fast gas chromatography-mass spectrometry (GC-MS) has been developed for the on-line monitoring of trihatomethanes (THMs) in chlorinated drinking water. The coupling of membrane introduction with fast GC-MS offers the advantage of membrane introduction as an on-line sampling device and fast GC-MS as a separation and identification method. While maintaining the on-line monitoring characteristic of traditional membrane introduction mass spectrometry (MIMS), the difficulty of distinguishing CHCl3 and CHBrCl2 in MIMS was overcome by rapid GC separation and MS analysis. Water permeated across the membrane affected the analysis of CHBr2Cl and CHBr3. A method based on controlling the injection temperature and injection time has been developed to overcome the moisture problem. This method is simple and less time consuming than the conventional moisture removing method. Under typical operating conditions, the sampling rate was about 20 samples h(-1) capable of on-line monitoring THMs in chlorinated drinking water. The detection limits of this system were found to be about 2 ppt, 4 ppt, 4 ppt, and 8 ppt for CHCl3 CHBrCl2, CHBr2Cl, and CHBr3, respectively.

Immunological quantitation and localization of ACAT-1 and ACAT-2 in human liver and small intestine

By using specific anti-ACAT-1 antibodies in immunodepletion studies, we previously found that ACAT-1, a 50-kDa protein, plays a major catalytic role in the adult human liver, adrenal glands, macrophages, and kidneys but not in the intestine. Acyl-coenzyme A:cholesterol acyltransferase (ACAT) activity in the intestine may be largely derived from a different ACAT protein. To test this hypothesis, we produced specific polyclonal anti-ACAT-2 antibodies that quantitatively immunodepleted human ACAT-2, a 46-kDa protein expressed in Chinese hamster ovary cells. In hepatocyte-like HepG2 cells, ACAT-1 comprises 85-90% of the total ACAT activity, with the remainder attributed to ACAT-2. In adult intestines, most of the ACAT activity can be immunodepleted by anti-ACAT-2. ACAT-1 and ACAT-2 do not form hetero-oligomeric complexes. In differentiating intestinal enterocyte-like Caco-2 cells, ACAT-2 protein content increases by 5-10-fold in 6 days, whereas ACAT-1 protein content remains relatively constant. In the small intestine, ACAT-2 is concentrated at the apices of the villi, whereas ACAT-1 is uniformly distributed along the villus-crypt axis. In the human liver, ACAT-1 is present in both fetal and adult hepatocytes. In contrast, ACAT-2 is evident in fetal but not adult hepatocytes. Our results collectively suggest that in humans, ACAT-2 performs significant catalytic roles in the fetal liver and in intestinal enterocytes.

Leukemia inhibitory factor expression in different endometrial locations between fertile and infertile women throughout different menstrual phases

PURPOSE

The purpose was to demonstrate the leukemia inhibitory factor (LIF) expression in different endometrial locations between fertile and infertile women throughout different menstrual phases. The relationship between progesterone level and LIF expression were evaluated.

METHODS

Endometrial biopsies were performed on idiopathic infertile and normal fertile women accepted the in follicular, periovulatory, and luteal phases. The luteal progesterone level was measured. Endometrial LIF immunostaining of luminal epithelium, glandular epithelium, and stroma were detected. The relationship between luteal LIF expression and progesterone level was evaluated.

RESULTS

Significant LIF expression was noted in the endometrium of fertile women rather than that of infertile women. The LIF expression was highest in the luminal epithelium, moderate in the glandular epithelium, and lowest in the stroma. The luminal and glandular epithelial staining were lowest in follicular phase, moderate in periovulatory phase, and strongest in luteal phase. The stromal LIF presented with a noncyclical manner. The LIF expression is not related with the progesterone level.

CONCLUSIONS

Endometrial LIF expression is related to human fertility. Endometrial LIF expression is dependent on cellular localizations and menstrual stages. Stronger LIF expression presents in the endometrial epithelium during luteal phase.

Restoration of gap junctional intercellular communication by caffeic acid phenethyl ester (CAPE) in a ras-transformed rat liver epithelial cell line

Caffeic acid phenethyl ester (CAPE), an active ingredient of honeybee propolis, has been identified as having anti-inflammatory, anti-viral and anti-cancer properties. Since the deficiency of gap junctional intercellular communication (GJIC) has been shown to be a characteristic of most cancer cells, this study was designed to test the hypothesis that the anti-carcinogenic activity of CAPE might be related to its ability to restore GJIC in tumorigenic GJIC-deficient cells (WB-ras2 cells). The results showed that CAPE restored GJIC, phosphorylation of connexin 43 (Cx43) and its normal localization on the plasma membrane in WB-ras2 cells after 3 days at 5 microg/ml concentration. Additionally, CAPE inhibited growth in soft agar and decreased the protein level of p21(ras). The results are consistent with the hypothesis that the anti-cancer mechanism of CAPE may be mediated by its ability to restore GJIC.

Successful application of extracorporeal membrane oxygenation and intra-aortic balloon counterpulsation as lifesaving therapy for a patient with amniotic fluid embolism

A woman in labor was noted to have amniotic fluid embolism. Extracorporeal membrane oxygenation and intra-aortic balloon counterpulsation were performed post partum, and the vital signs became stable. The ensuing recovery was uneventful. We conclude that extracorporeal membrane oxygenation and intra-aortic balloon counterpulsation should be considered to save the life of a patient with amniotic fluid embolism and left ventricular failure unresponsive to medical therapy.

Decreased CD10-positive mature granulocytes in bone marrow from patients with myelodysplastic syndrome

OBJECTIVE

We retrospectively examined the maturation of the granulocytic cell lineage in bone marrow specimens from patients with myelodysplastic syndrome (MDS) by flow cytometry using both light scatter and surface marker characteristics, including CD10 and myeloid lineage-associated antigens.

PATIENTS

The 7 MDS cases we studied included 2 patients with refractory anemia (RA), 3 with RA with ringed sideroblasts, 1 with RA with excess of blasts, and 1 unclassified case. Another 7 patients matched for age and sex who received bone marrow aspirates for lymphoma staging (all negative for lymphoma involvement or any other hematologic abnormalities) were selected as the control group.

RESULTS

The percentage of CD10(+) mature granulocytes was significantly lower in patients with MDS than in control patients. Additionally, all patients with MDS had less than 50% CD10(+) cells in the granulocytic lineage. In contrast, only 1 of the 7 control patients had less than 50% CD10(+) cells (P <.01).

CONCLUSIONS

These results suggest that flow cytometry might be a useful adjunct in the assessment of patients with suspected MDS. Further studies to correlate CD10(+) mature granulocytes from MDS cases with other benign hematologic disorders are indicated to confirm our evaluation.

Lambda-carrageenan-induced inhibition of gap-junctional intercellular communication in rat liver epithelial cells

lambda-Carrageenan, a food additive extracted from red seaweed, is widely used as an emulsifier, stabilizer, or thickener. Previously, it has been shown that carrageenan could play a role in carcinogenesis. However, the mechanism by which it might influence the multimechanism, multistep process of carcinogenesis is not known. Gap-junctional intercellular communication (GJIC) has been associated with maintaining homeostatic regulation of cell proliferation and differentiation. Most cancer cells have dysfunctional GJIC, and many tumor-promoting chemicals, growth factors, and oncogenes can downregulate GJIC. The experiments in this study were designed to test the hypothesis that carrageenan might function as a tumor-promoting chemical by inhibiting GJIC. To test this hypothesis, nontumorigenic rat liver epithelial cells were exposed to carrageenan, and GJIC was measured. Western blot analysis and immunofluorescent staining were used to monitor the phosphorylation and localization of connexin 43. The data revealed inhibition of GJIC by carrageenan similar to that by the well-documented tumor promoter phorbol ester. However, the phosphorylation and localization of connexin 43 were not altered. Although the mechanism by which carrageenan inhibits GJIC is unknown, carrageenan's influence on the carcinogenic process might be via its ability to be a tumor promoter.

Double phase conjugation with orthogonally polarized beams in a BaTiO(3) crystal

We have demonstrated experimentally the simultaneous self-conjugation of extraordinarily and ordinarily polarized light waves (lambda=514 nm), with the polarization state preserved, in a Ce:BaTiO(3) crystal. Conjugate o waves originate from coupling between o and e waves by means of a circular photogalvanic effect. The conjugator also takes advantage of the Ce:BaTiO(3) crystal, for which it is easy to generate an extraordinary conjugate beam by photorefractive backscattering. This beam of light is necessary for double phase conjugation.

Serologic and molecular evidence of Ehrlichia spp. in coyotes in California

In order to determine the role of coyotes in the epidemiology of granulocytic and monocytic ehrlichial agents in California (USA), we tested 149 serum samples for antibodies against Ehrlichia equi, E. risticii, and E. canis, using an indirect immunofluorescent antibody test. Polymerase chain reaction (PCR) assay was used to survey for the presence of members of the E. phagocytophila genogroup, E. risticii and E. canis in blood samples of 95 coyotes. Sixty-eight (46%) samples were seropositive for E. equi, two (1%) for E. risticii and none of the samples had antibodies reactive to E. canis. Two and one coyote were positive for E. risticii and members of the E. phagocytophila genogroup by PCR assay, respectively. In contrast, the 95 samples were negative for E. canis by PCR. Ninety-five percent of the 68 E. equi seropositive coyotes and the one coyote PCR positive for members of the E. phagocytophila genogroup originated from a coastal area. However, the two E. risticii seropositive coyotes and the two coyotes PCR positive for E. risticii were from northern California. Sequence analysis of the three amplified PCR products revealed the agent to be similar in two coyotes to the sequences of E. risticii from horses originating from northern California and identical in one coyote to the agent of human granulocytic ehrlichiosis and E. equi from California. Thus, coyotes are exposed to granulocytic ehrlichiae and E. risticii and may play a role in the epidemiology of these ehrlichial agents in California.

Effect of different concentrations of recombinant leukemia inhibitory factor on different development stage of mouse embryo in vitro

PURPOSE

To assess the influence of different concentrations of recombinant human leukemia inhibitory factor (LIF) on the in vitro development of mouse embryos.

METHODS

The 2- to 4-cell embryos of CB6F1 mice were cultured in the human tubal fluid (HTF) media containing different concentrations of LIF. Mouse embryos were divided into seven groups: (1) HTF; (2) 1500 IU/ml LIF; (3) 1000 IU/ml LIF; (4) 750 IU/ml LIF; (5) 500 IU/ml LIF; (6) 250 IU/ml LIF; (7) 125 IU/ml LIF. The embryonic numbers of different stages including 5-8 cell, 9-16 cell, morula, blastocyst, and hatching blastocyst were recorded.

RESULTS

The percentage of early embryo stage (2-cell embryos to 6- to 16-cell stages) in all groups were nonsignificantly different. There were higher formation rates of preimplantation embryos (morula to hatching blastocyst) in groups 2, 3, 4, and 5 than in groups 1, 6 and 7.

CONCLUSIONS

LIF has positive effects on preimplantation embryo development and has nonsignificant influence on the early embryo development. The lowest concentration of LIF which could provide the optimal embryo development is 500 IU/ml.

Quantitative analysis of the regulation of leukocyte chemosensory migration by a vascular prosthetic biomaterial

The need for improved, infection-resistant vascular biomaterials calls for more objective evaluation of the immune pathophysiology of implantable prosthetic materials. In this study we have developed a new strategy to quantitatively characterize population-averaged responses of immune cell migration on vascular prosthetic materials. This approach, incorporating a chemokinetically regulated "biomaterial-gel" sandwich configuration, was applied to quantify both random and directed modes of the chemosensory migration of human neutrophil leukocytes on expanded polytetrafluoroethylene (ePTFE). Our studies show that (a) microporous, synthetic materials like ePTFE suppress the basal rate of random cell migration relative to that reported on non-porous control surfaces; (b) stimulation with chemoattractant (formyl peptide) can significantly elevate rates of random and directed migration on ePTFE; and (c) protein conditioning of ePTFE with albumin or immunoglobulin G can differentially modulate the rates and relative proportion of random and directional components of leukocyte migration response to chemoattractant. This, to our knowledge, is the first objective quantitation of chemokinetically regulated cell migration on implantable prosthetic materials.

Adaptive optics: wave-front correction by use of adaptive filtering and control

A class of adaptive-optics problems is described in which phase distortions caused by atmospheric turbulence are corrected by adaptive wave-front reconstruction with a deformable mirror, i.e., the control loop that drives the mirror adapts in real time to time-varying atmospheric conditions, as opposed to the linear time-invariant control loops used in conventional adaptive optics. The basic problem is posed as an adaptive disturbance-rejection problem with many channels. The solution given is an adaptive feedforward control loop built around a multichannel adaptive lattice filter. Simulation results are presented for a 1-m telescope with both one-layer and two-layer atmospheric turbulence profiles. These results demonstrate the significant improvement in imaging resolution produced by the adaptive control loop compared with a classical linear time-invariant control loop.

Sperm cryopreservation with empty human or mouse zona pellucidae. A comparison

OBJECTIVE

To compare empty zona pellucidae (ZP) and human of mouse oocytes for sperm cryopreservation.

STUDY DESIGN

ZP was prepared by evacuating the cytoplasm of human or mouse oocytes. The evacuated ZP were injected with spermatozoa from patients with severe oligoasthenozoospermia from normally fertile men. After a freezing-thawing procedure, the spermatozoa were aspirated outside the ZP. According to the different origins of ZP and sperm, the spermatozoa number per ZP, motile sperm number before freezing and after thawing, lost sperm number per ZP after freezing and sperm recovery rate were compared.

RESULTS

Spermatozoa number, motile sperm number before freezing and after thawing, lost sperm number per ZP and sperm recovery rate in all groups were comparable. The total mean motile sperm number before freezing and after thawing, mean lost sperm number after thawing and sperm recovery rate were 15.1%, 12%, 1.6% and 80%, respectively.

CONCLUSION

ZP is an ideal vehicle for cryopreservation of sperm collected from patients with severe oligoasthenozoospermia. There were no differences between human and mouse ZP for sperm storage.

A case-control study of successful maintenance of a substantial weight loss: individuals who lost weight through surgery versus those who lost weight through non-surgical means

OBJECTIVE

To determine if method of weight loss (surgery; non-surgery) is associated with current levels of psychosocial functioning or current weight maintenance behaviors in individuals who have lost large amounts of weight.

DESIGN

Subjects were 67 cases and 67 controls selected from the National Weight Control Registry, a longitudinal study of individuals successful at long-term maintenance of weight loss. Cases had initially lost weight through bariatric surgery while controls had lost weight through non-surgical means. The current psychosocial functioning and weight maintenance behaviors of cases and controls were assessed and compared.

RESULTS

Cases and controls were matched on gender, current weight and total weight loss. Surgical cases reported significantly higher fat intake and lower physical activity levels. There were no differences in cases' and controls' reports of the impact of weight loss on other areas of their lives, neither were there differences on measures of depression or binge-eating.

CONCLUSIONS

Reported improvement in psychosocial functioning did not depend upon how weight was initially lost, but cases and controls appear to be using very different behaviors to maintain their weight losses.

Identification and genetic characterization of Haemophilus influenzae genetic island 1

The type b capsule of pathogenic Haemophilus influenzae is a critical factor for H. influenzae survival in the blood and the establishment of invasive infections. Other pathogenic factors associated with type b strains may also play a role in invasion and sustained bacteremia, leading to the seeding of deep tissues. The gene encoding haemocin is the only noncapsular gene found to be specific to type b strains until now. Here we report the discovery of an approximately 16-kb genetic locus, HiGI1, that is present primarily in type b strains. Pulsed-field gel electrophoresis and Southern hybridization were used to map this new locus between secG (HI0445) and fruA (HI0446), which are contiguous in Rd, a nonpathogenic derivative of a serotype d strain. It is inserted at the 3' end of tRNA(4)(Leu) and has regions whose G+C content differs from the average genomic G+C content of H. influenzae. An integrase gene, which encodes a CP4-57 like integrase, is located downstream of tRNA(4)(Leu). Hybridization probes based on the sequences within the HiGI1 locus have been used to screen 61 H. influenzae strains (2 type a, 22 type b, 2 type c, 1 type d, 3 type e, 7 type f, and 21 nontypeable H. influenzae [NTHi]) from our collection. This HiGI1 locus exists in all 22 type b strains and two NTHi strains and is likely to have been acquired by an ancestral type b strain.

Deep neck infections in diabetic patients

PURPOSE

Deep neck infections may be lethal if life-threatening complications occur, especially in immunocompromised hosts such as diabetic patients. This study was undertaken to better define the clinical features and prognosis of deep neck infections in the diabetic patients with special emphasis on the use of empirical antibiotics and the role and timing of surgical management.

PATIENTS AND METHODS

A retrospective analysis of 105 consecutive patients treated at a single institution during a 9-year period was conducted. Of these, 30 patients also presented with diabetes mellitus.

RESULTS

Compared with the nondiabetic patients, the unique features of deep neck infections in diabetic patients were as follows: (1) older age, (2) tendency of unclear infection source, (3) tendency to involve multiple spaces, (4) required more aggressive surgical intervention, (5) prolonged hospitalization, and (6) higher complication rate. The differences were statistically significant (P< .05). There were no significant differences in the complete blood count/ differential count positive findings and fever between the 2 groups (P> .05). Bacterial cultures showed that Klebsilla pneumoniae was the most common causative pathogen in diabetic patients.

CONCLUSIONS

In deep neck infection patients with diabetes mellitus, the clinical course is more severe and there is a poorer prognosis. Thus, in treating them, we should keep close observation, appropriately control the diabetes, detect the life-threatening complications early, perform aggressive surgical treatment if fluctuation or complication occurs, and take into account the preponderance of K pneumoniae when administering the empirical antibiotics.

Long-term trends in exposures to nickel aerosols

A comprehensive evaluation of temporal changes in exposure to nickel aerosols in the nickel-producing and nickel-using industries was conducted. For various nickel compounds, trends in the geometric mean exposure levels were evaluated on the basis of job group, building, plant, and industrial sector. At each level of classification, approximately two-thirds of the data provided evidence of workplace declines in exposures. Depending on how exposure measurements were aggregated, approximately one-quarter to one-half of the data produced statistically significant trends, with far more exposures declining than increasing over time. Whereas significantly negative linear trends were detected for total nickel exposures in the mining (-7%/yr), smelting (-9%/yr), and refining (-7%/yr) sectors, total nickel exposures in milling showed a significantly positive trend (+4%/yr). When the data were classified at the job group, building, or plant level, the median rate of change in exposure levels was -4, -6, and -3%/yr, respectively. For a subset of the data, effects of various factors related to work environment, process, and nature of the job on trends in exposure levels were evaluated. When such factors were examined simultaneously, the results suggested that the decline in exposures was greater in workplaces with no ventilation system compared with ventilated workplaces, in groups of workers who performed similar rather than diverse tasks, and in North American workplaces compared with workplaces in Europe and Western Australia. These results could be used in the design of prospective sampling protocols and in future retrospective health-effects studies of workers in the nickel industries.

Purification and characterization of neutral sphingomyelinase from Helicobacter pylori

Phospholipase activities of human gastric bacterium, Helicobacter pylori, are regarded as the pathogenic factors owing to their actions on epithelial cell membranes. In this study, we purified and characterized neutral sphingomyelinase (N-SMase) from the superficial components of H. pylori strains for the first time. N-SMase was purified 2083-fold with an overall recovery of 37%. The purification steps included acid glycine extraction, ammonium sulfate precipitation, CM-Sepharose, Mono-Q, and Sephadex G-75 column chromatography. Approximate molecular mass for the native N-SMase was around 32 kDa. When N-omega-trinitrophenylaminolauryl sphingomyelin (TNPAL-SM) was used as a substrate, the purified enzyme exhibited a K(m) of 6.7 microM and a V(max) of 15.6 nmol of TNPAL-sphingosine/h/mg of protein at 37 degrees C in 50 mM phosphate-buffered saline, pH 7.4. N-SMase reaches optimal activity at pH 7.4 and has a pI of 7.15. The enzyme activity is magnesium dependent and specifically hydrolyzed sphingomyelin and phosphatidylethanolamine. The enzyme also exhibits hemolytic activity on human erythrocytes. According to Western blot analysis, a rabbit antiserum against purified N-SMase from H. pylori cross-reacted with SMase from Bacillus cereus. Sera from individuals with H. pylori infection but not uninfected ones recognizing the purified N-SMase indicated that it was produced in vivo. In enzyme-linked immunosorbent assays, the purified N-SMase used as an antigen was as effective as crude protein antigens in detecting human antibodies to H. pylori.

Regulation of plastid rDNA transcription by interaction of CDF2 with two different RNA polymerases

The plastid genome is known to be transcribed by a plastid-encoded prokaryotic-type RNA polymerase (PEP) and by a nucleus-encoded phage-type RNA polymerase (NEP). The spinach plastid rrn operon promoter region harbours three different, overlapping promoters. Two of them are of the prokaryotic type. The third promoter is a non-consensus-type NEP promoter. We separated three different transcriptional activities from spinach chloroplasts: PEP, the phage-type RNA polymerase NEP-1, and a third, hitherto undescribed transcriptional activity (NEP-2). NEP-2 specifically transcribes the rrn operon in the presence of the transcription factor CDF2. CDF2 was previously shown to recruit PEP to the rrn promoter to repress transcription. Together, our results suggest the existence of a third RNA polymerase in plastids and a mechanism of rDNA transcriptional regulation that is based on the interaction of the transcription factor CDF2 with two different transcriptional systems.

Expression of c-Myc and p53 correlates with clinical outcome in diffuse large B-cell lymphomas

We performed a retrospective immunohistochemical study of the relationships between clinical manifestations and outcomes of diffuse large B-cell lymphoma (DLBCL) and expression of oncogenic proteins in 21 cases of DLBCL at various clinical stages. Cases of nodal origin expressed p53 more often and presented with high clinical stage more frequently than those of extranodal origin. Expression of c-Myc or p53, but not Bcl-6, Bcl-2, or Bcl-1, showed a statistically significant positive correlation with high clinical stage at presentation and with high or high-intermediate risk. Coexpression of c-Myc and p53 occurred in 7 of 12 patients with high clinical stage but was absent in patients with low clinical stage; coexpression was more frequent in patients with high or high-intermediate risk than in patients with low or low-intermediate risk. Four patients with this coexpression pattern demonstrated an unusually aggressive clinical course (median survival, 7 months). Coexpression of c-Myc and p53 seems to be a better indicator than the MIB1 proliferative index for identification of a cohort of aggressive disease in patients with DLBCL.

Expression and high-level secretion of Trichoderma reesei endoglucanase I in Yarrowia lipolytica

The endoglucanase I (EGI) from fungus Trichoderma reesei was cloned, expressed, and secreted from Yarrowia lipolytica using the XPR2 promoter. The signal sequence of EGI transferred from T. reesei was efficiently processed in the Y. lipolytica secretory pathway and directed the secretion of active EGI into the culture medium. However, the recombinant EGI produced from YLCSIn strain was hyperglycosylated and significantly larger than the native enzyme produced by the parent strain. The expression of EGI using XPR2 preproregion has caused secretion of modified proteins that still retained cellulase activity. This resulted from imprecise processing of the N-terminus of recombinant protein. While the batch culture produced 5 mg EGI/L from YLCSIn strain, the EGI yield was increased approx 20-fold when the fed-batch fermentation process strategy in combination with the high-cell density cultivation technique was employed. These results showed that the Y. lipolytica is a useful host organism for production of a large amount of large size heterologous proteins, especially when used in combination with high-cell density and fed-batch culture techniques.

Prolonged culture of human cryopreserved embryos with recombinant human leukemia inhibitory factor

PURPOSE

To evaluate the efficiency of recombinant human leukemia inhibitory factor (LIF) in the prolonged culture of human cryopreserved-thawing embryos.

METHODS

After thawing, all embryos were divided into four groups: (1) Human tubal fluid (HTF), (2) HTF + LIF, (3) M3TH medium, and (4) M3TH medium plus LIF. Following prolonged culture, embryo development in each group was compared.

RESULTS

In embryo development from about the 2- to 4-cell to 9- to 16-cell stage, there were nonsignificant differences between each group. There was lower morula formation rate in group 1 (6.9%) than those in other groups (23.2%, 19.7%, 23.1%). The lower blastocyst formation in group 1 and 3 (0%, 0%) than those in group 2 and 4 (11.0%, 12.8%) were noted.

CONCLUSIONS

LIF is beneficial for preimplantation embryos. LIF does not influence the early embryo development. LIF-supplemented HTF provided a similar culture environment for thawing embryos as LIF-supplemented M3TH medium.

Artificial insemination. Role of endometrial thickness and pattern, of vascular impedance of the spiral and uterine arteries, and of the dominant follicle

OBJECTIVE

To assess the roles of endometrial thickness and pattern, as well as vascular impedance of the spiral and uterine arteries and dominant follicle in predicting the pregnancy rate in women receiving controlled ovarian hyperstimulation (COH) following by intrauterine insemination (IUI).

STUDY DESIGN

All idiopathically infertile couples who accepted COH + IUI for the first time were prospectively included. The COH agents included clomiphene citrate and human menopausal gonadotropins. Endometrial thickness and pattern (trilaminar, nontrilaminar) and vascular impedance (pulsatility index [PI], resistance index [RI]) of the spiral and uterine arteries and ovarian dominant follicle were measured on the day of IUI. Analyses were made of the influences on pregnancy outcomes by endometrial thickness and pattern as well as Doppler surveys of the spiral and uterine arteries and dominant follicle.

RESULTS

A total of 110 couples with 110 cycles were enrolled, and there were 16 resulting pregnancy cycles. Trilaminar endometrium appeared in 87.5% and 57.4% of pregnant and nonpregnant women (P = .022), respectively. The pregnancy rates in trilaminar and nontrilaminar groups were 17.9% and 6.3%, respectively (P = .022). Endometrial thickness and PI/RI values for the spiral artery and uterine arteries and dominant follicle in pregnant women (12.1 +/- 2.6; 1.28 +/- 0.33/0.68 +/- 0.12; 2.67 +/- 0.51/0.72 +/- 0.32; 0.71 +/- 0.19/0.54 +/- 0.06 mm, respectively) were not statistically different from those for nonpregnant women (11.0 +/- 2.9; 1.46 +/- 0.49/0.71 +/- 0.21; 2.81 +/- 0.65/0.88 +/- 0.34; 0.74 +/- 0.24/0.55 +/- 0.09, respectively).

CONCLUSION

A trilaminar endometrium on the day of IUI provides a favorable prediction of pregnancy. Endometrial thickness and Doppler surveys of the spiral and uterine arteries and dominant follicle do not have useful predictive value in COH + IUI.

Low-dose aspirin for infertile women with thin endometrium receiving intrauterine insemination: a prospective, randomized study

PURPOSE

The objective was to evaluate the effect of aspirin on infertile women with thin endometrium.

METHODS

Patients who had thin endometrium (< or = 8 mm) and intrauterine insemination were divided into the aspirin and nonaspirin groups. Endometrial pattern (trilaminar and nontrilaminar) and thickness, the pulsatility index (PI) and resistance index (RI) of the uterine artery, spiral artery, and ovarian dominant follicles, and pregnancy rates of both groups were measured.

RESULTS

A total of 114 and 122 women were included in the aspirin and nonaspirin groups, respectively. There were significantly higher percentages of trilaminar endometrium (46.5% vs. 26.2%) and pregnancy rate (18.4% vs. 9.0%) after aspirin therapy. There was nonsignificant difference in the endometrial thickness, and PI/RI values of the uterine artery, spiral artery, and ovarian dominant follicle between both groups.

CONCLUSIONS

Higher pregnancy rate and better endometrial pattern were achieved in patients with thin endometrium after aspirin administration. Aspirin therapy could not significantly increase the endometrial thickness and the resistance of uterine and ovarian flow.

Factors affecting the outcome of surgical treatment of acromegaly

PURPOSE

To assess the results of and factors associated with the outcome of surgery for acromegaly.

METHODS

We retrospectively examined the medical records of acromegalic patients who underwent trans-sphenoidal adenomectomy at our hospital during the period of January 1991 through August 1997. Preoperative evaluations included measurement of basal serum growth hormone (GH), insulin-like growth factor-I (IGF-I), prolactin (PRL), GH response to oral glucose, and GH and PRL response to bromocriptine, as well as pituitary magnetic resonance (MR) imaging. Postoperative evaluations included measurement of basal serum GH and IGF-I concentrations, and pituitary MR imaging.

RESULTS

Thirty patients (14 men) with a mean age of 38 years were included. The mean follow-up period was 50 months (range, 15-90 mo). Ten of the 30 patients (33%) had early postoperative (1 mo after surgery) GH levels of less than 5 ng/mL. Twenty patients (67%) had final postoperative (last follow-up, 15-90 mo after surgery) GH levels of less than 5 ng/mL. Preoperative GH levels were positively correlated with early postoperative GH levels (r = 0.458, p = 0.011) and final postoperative GH levels (r = 0.479, p = 0.007). Early postoperative GH levels were also positively correlated with final postoperative GH levels (r = 0.595, p = 0.001). Tumor grade and stage were not significantly correlated with early or final postoperative GH levels. Thirteen of 21 patients (62%) who had postoperative MR imaging follow-up had residual tumor. There was no surgical mortality.

CONCLUSIONS

These results highlight that acromegaly is not easily treated with surgery alone. The preoperative GH level was associated with the surgical outcome.

Impairment of cerebrovascular reactivity to acetazolamide in patients with normal pressure hydrocephalus

Cerebrovascular reactivity (CVR) to acetazolamide was investigated in 41 patients with normal pressure hydrocephalus (NPH). The aetiology was subarachnoid haemorrhage in 20 patients, trauma in nine, brain tumour in three and idiopathic in nine. Mean cerebral blood flow (CBF) of the whole brain was measured by performing first-pass radionuclide angiography using 99Tcm-hexamethylpropylene++ amine oxime. Cerebrovascular reactivity was measured as the percentage change from the baseline mean CBF value after the administration of 500 mg of acetazolamide. Cerebrovascular reactivity was significantly (P < 0.001) reduced in patients with the complete triad of NPH (1.4 +/- 3.1%), regardless of the aetiology, compared with normal controls (14.7 +/- 3.3%). Patients with the incomplete triad also showed significantly (P < 0.05) reduced CVR (9.6 +/- 5.4%). Patients with the complete triad had significantly (P < 0.001) lower CVR than those with the incomplete triad. Post-operative CVR in both groups (20 patients with the complete triad and 9 patients with the incomplete triad) increased significantly, from 1.5 +/- 3.5% to 10.0 +/- 5.5% (P < 0.001) and from 8.7 +/- 4.9% to 14.9 +/- 5.4% (P < 0.05), respectively. Cerebrovascular reactivity is impaired in patients with NPH regardless of the aetiology and improves after shunting.

Longitudinal doppler sonographic measurements of vascular impedance in the central and peripheral spiral arteries throughout pregnancy

PURPOSE

We assessed vascular impedance in the spiral arteries in the central and peripheral placental bed throughout uncomplicated pregnancies.

METHODS

Transabdominal color Doppler sonography was used to measure the pulsatility index (PI), resistance index (RI), and peak systolic velocity in the central and peripheral spiral arteries in 94 women with uncomplicated singleton pregnancies. Sonographic examinations took place approximately every 5 weeks from 10 to 40 weeks' menstrual age.

RESULTS

PI, RI, and peak systolic velocity were not different in the central versus the peripheral segments of the spiral arteries. The PI and RI values of central spiral arteries after 25 weeks' menstrual age. The PI and RI values of peripheral arteries decreased after 20 weeks' menstrual age.

CONCLUSIONS

Additional subjects are needed to clarify changes in the impedance of central and peripheral spiral arteries over the course of normal and complicated pregnancies.

Effects of radiotherapy for nasopharyngeal carcinoma on the paranasal sinuses: study based on computed tomography scanning

OBJECTIVE

The purpose of this study was to determine if radiotherapy for nasopharyngeal carcinoma causes mucosal disease of the paranasal sinuses.

DESIGN

This study was a retrospective study.

SETTING

This study was conducted at a tertiary care centre.

METHOD

A series of 69 newly diagnosed patients, without pre-existing sinus disease, who were treated with high-dose radiotherapy participated.

MAIN OUTCOME MEASURES

The prevalence, severity, and time course of mucosal abnormalities were analyzed, as judged by consecutive computed tomographies (CTs).

RESULTS

The CT study revealed that 58.8% of the postirradiation scans had mucosal disease of the sinuses. The maxillary sinus had the highest prevalence (42.3%) without statistical significance (p = .10). The difference by McNemar test for two follow-up scans was not significant (p = .48) and by Kappa test was significant (p = .04). The relationship between the prevalence and the time course post radiotherapy revealed that it remained a high prevalence until after the 4-year follow-up scans.

CONCLUSIONS

The results of this study confirm that chronic sinus disease is a common late complication of radiotherapy and it persists for years. Thus, aggressive treatment is indicated.

Fetal renal volume assessment by three-dimensional ultrasonography

OBJECTIVE

This study was undertaken to measure fetal renal volume by means of three-dimensional ultrasonography and to use those data to establish the accurate constant and formula for fetal renal volume assessment with two-dimensional ultrasonography.

STUDY DESIGN

Singleton fetuses between 15 and 40 weeks' gestation were included. The volumes of both fetal kidneys were measured with three-dimensional ultrasonography. Three fetal renal diameters (largest anteroposterior, transverse, and longitudinal diameters) were measured, and the constant of the fetal renal volume formula was calculated. Linear regression curves were made for each kidney from the fetal renal volume, the three diameters, and the constant.

RESULTS

A total of 112 fetuses were included. The following fetal renal volume formula was established: Fetal renal volume = Constant (R) x Largest anteroposterior diameter (x) x Largest transverse diameter (y) x Largest longitudinal diameter (z). The volumes, the three diameters, and the constants appeared different between the right and left kidneys but not statistically significantly so.

CONCLUSION

Three-dimensional ultrasonography is useful in assessing fetal renal volume. The fetal renal volume formula makes possible accurate measurements of fetal renal volume by two-dimensional ultrasonography.

Gap junctions and the regulation of cellular functions of stem cells during development and differentiation

In multicellular organisms, the role of gap junction intercellular communication (GJIC) in the regulation of cell proliferation, cell differentiation, and apoptosis is becoming increasingly recognized as one of the major cellular functions from the start of the fertilized egg, through normal development of the embryo and fetus, to the sexual maturation of the adult and ultimately to the maintenance of health of the aging adult. Given that the function of this membrane-associated protein channel is to synchronize electrotonic or metabolic functions, differential regulation of function at the transcriptional, translational, and posttranslational levels of a family of highly evolutionarily conserved genes (connexins) needs to be considered. Both inherited mutations and environmental modulation of GJIC could, in principle, affect the function of gap junctions to control cell proliferation, cell differentiation, and apoptosis, thereby leading to a wide variety of pathologies. We review a few techniques used to characterize the ability of stem and progenitor cells to perform GJIC.

Effects of the immunomodulator tilorone on the acetylation of 2-aminofluorene and DNA-2-aminofluorene adducts in the rats

The present studies were undertaken to determine the effect of tilorone dihydrochloride (a synthetic interferon inducer) on the in vivo acetylation of 2-aminofluorene and DNA-2-aminofluorene adducts. For in vivo examination, pretreatment with tilorone dihydrochloride (50 mg/kg) 48 hr prior to the administration of 2-aminofluorene (50 mg/kg) resulted in a 35% and 29% increase in the fecal and urinary recovery of N-acetyl-2-aminofluorene and a 52% increase in the metabolic clearance of 2-aminofluorene to N-acetyl-2-aminofluorene. Following the exposure of rats to the 2-aminofluorene with or without pretreatment with tilorone dihydrochloride, DNA-2-aminofluorene adducts were determined in liver, bladder, lung and also in circulating leukocytes. The DNA-2-aminofluorene adducts in liver were increased by pretreatment with tilorone dihydrochloride. This is the first demonstration of tilorone-induced increasing in N-acetylation of carcinogens and DNA-carcinogen adducts in vivo.

Modulation of cell-cell communication in the cause and chemoprevention/chemotherapy of cancer

Chemopreventive or chemotherapeutic agents have been those that either kill cancer cells to a differential degree over the non-cancer cells or those chemicals that either block the induction of tumors in carcinogen-treated animals or retard transplanted tumors in animals. Carcinogenesis is a multi-stage, multi-mechanism process, involving the irreversible alteration of a stem cell ("initiation"), followed by the clonal proliferation of the initiated cell ("promotion"). To develop a strategy for intervention with chemoprevention/chemotherapeutic chemicals, the basic mechanism(s) of carcinogenesis must be understood. Gap junction intercellular communication (GJIC) regulates cell growth, differentiation, apoptosis and adaptive functions of differentiated cells. Normal cells have functional GJIC while cancer cells do not. Tumor promoters and oncogenes inhibit GJIC, while anti-tumor promoter and anti-oncogene drugs can reverse the down-regulation of GJIC. Transfection of gap junction genes (connexins) has been shown to reverse the tumorigenic phenotype. If prevention/treatment of cancer is to occur, prevention of the chronic down regulation of GJIC by tumor promoters in non-tumorigenic but initiated cells or the up-regulation of GJIC in stably down-regulated GJIC in tumor cells must occur to prevent or to treat cancers.

Transitional cell carcinoma in dialysis patients

OBJECTIVE

The aim of our study was to determine whether there is an increased incidence of urothelial cancer, especially transitional cell carcinoma (TCC), in uremic patients on dialysis.

METHODS

Retrospective chart analyses were completed for 1,910 uremic patients undergoing maintenance dialysis between January 1987 and December 1997. The incidence of urinary tract cancer was assessed. Only the patients with cancers diagnosed after start of dialysis were enrolled in the study.

RESULTS

Of the 1,910 patients, 70 had concomitant urinary tract cancers. Nineteen patients (0.99%), including 17 patients with TCC and 2 patients with renal cell carcinoma, were diagnosed after the initiation of dialysis. The average duration from dialysis to TCC diagnosis was 38.3 (range 2-144) months. Painless gross hematuria was the cardinal symptom in 16 of the 17 patients with TCC. In the 17 patients with TCC, no distant metastases were found at the time of diagnosis. Fourteen patients (82.3%) were stage 0 or A, and 1 patient was stage B1.

CONCLUSIONS

The 0.89% incidence of TCC in our dialysis patients was high as compared with that of the general population. The risks of developing urinary TCC in dialysis patients were examined, and we suggest that immunosuppressive stage, dialysis procedure, and chronic bladder irritation (decreased urinary wash effect) may play a part in the development of urinary TCC in dialysis patients. Early detection of hematuria due to regular visits and decreased exposure of urinary tract epithelium to carcinogens from urine may explain why early-stage TCC was seen in most of our patients.

Precipitate delivery and postpartum hemorrhage after term induction with 200 micrograms misoprostol

Misoprostol has been widely applied in early pregnancy termination and term pregnancy induction. However, the upper dosage limit of misoprostol through vaginal route has not been firmly established. Most popular dosages of vaginal misoprostol recommended are 25, 50 or 100 micrograms. There are no reports on the dangers of high-dosage misoprostol 200 micrograms as used in term labor induction. We present a primiparaous woman who was administered 200 micrograms misoprostol vaginally for term labor induction. The following precipitate delivery resulted in multiple lacerations of the isthmus, cervix and vagina, postpartum hemorrhage and disseminated intravascular coagulopathy. Inevitably, a hysterectomy was performed. A postsurgical check of the uterus confirmed lacerations of the isthmus and internal cervix. This rare complication suggests the possible dangers of vaginal misoprostol doses as high as 200 micrograms for term induction of labor at term.

Localization of human acyl-coenzyme A: cholesterol acyltransferase-1 (ACAT-1) in macrophages and in various tissues

To investigate the distribution of acyl-coenzyme A:cholesterol acyltransferase-1 (ACAT-1) in various human tissues, we examined tissues of autopsy cases immunohistochemically. ACAT-1 was demonstrated in macrophages, antigen-presenting cells, steroid hormone-producing cells, neurons, cardiomyocytes, smooth muscle cells, mesothelial cells, epithelial cells of the urinary tracts, thyroid follicles, renal tubules, pituitary, prostatic, and bronchial glands, alveolar and intestinal epithelial cells, pancreatic acinar cells, and hepatocytes. These findings showed that ACAT-1 is present in a variety of human tissues examined. The immunoreactivities are particularly prominent in the macrophages, steroid hormone-producing cells, followed by hepatocytes, and intestinal epithelia. In cultured human macrophages, immunoelectron microscopy revealed that ACAT-1 was located mainly in the tubular rough endoplasmic reticulum; immunoblot analysis showed that the ACAT-1 protein content did not change with or without cholesterol loading; however, on cholesterol loading, about 30 to 40% of the total immunoreactivity appeared in small-sized vesicles. These vesicles were also enriched in 78-kd glucose-regulated protein (GRP 78), a specific marker for the endoplasmic reticulum. Immunofluorescent microscopy demonstrated extensive colocalization of ACAT-1 and GRP 78 signals in both the tubular and vesicular endoplasmic reticulum before and after cholesterol loading. These results raise the possibility that foam cell formation may activate an endoplasmic reticulum vesiculation process, producing vesicles enriched in the ACAT-1 protein.

Bartonella spp. isolated from wild and domestic ruminants in North America

Bartonella species were isolated from 49% of 128 cattle from California and Oklahoma, 90% of 42 mule deer from California, and 15% of 100 elk from California and Oregon. Isolates from all 63 cattle, 14 deer, and 1 elk had the same polymerase chain reaction/restriction fragment length polymorphism profiles. Our findings indicate potential for inter- and intraspecies transmission among ruminants, as well as risk that these Bartonella spp. could act as zoonotic agents.

Study and fabrication of the PbTiO3 thin film acoustic sensors

In this study, thin film acoustic sensors were fabricated utilizing the r.f. planar magnetron sputtering method and micromachining techniques. Underwater testing results indicated that the maximum receiving sensitivity of -117.8 dBV microbar(-1) occurred at 5.5 MHz. For the acoustic sensors tested, the highest transmitting intensities were 26.5 dBV/microbar at a fundamental resonant frequency of 7 MHz, 40.4 dBV microbar(-1) at the third harmonic of 21 MHz, and 37.1 dBV microbar(-1) at half the fundamental frequency or 3.5 MHz. Underwater measurements also indicated that the larger the sample area, the higher the transmitting intensity and receiving sensitivity.

Human acyl-CoA:cholesterol acyltransferase-1 is a homotetrameric enzyme in intact cells and in vitro

Acyl-CoA:cholesterol acyltransferase (ACAT) is a key enzyme in cellular cholesterol homeostasis and in atherosclerosis. ACAT-1 may function as an allosteric enzyme. We took a multifaceted approach to investigate the subunit composition of ACAT-1. When ACAT-1 with two different tags were co-expressed in the same Chinese hamster ovary cells, antibody specific to one tag caused co-immunoprecipitation of both types of ACAT-1 proteins. Radioimmunoprecipitations of cells expressing the untagged ACAT-1 or the 6-histidine-tagged ACAT-1 yielded a single radiolabeled band of predicted size on SDS-polyacrylamide gel electrophoresis. These results show that ACAT-1 exists as homo-oligomers in intact Chinese hamster ovary cells. We solubilized HisACAT-1 with the detergent deoxycholate or CHAPS (3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonic acid), performed gel filtration chromatography and sucrose density gradient centrifugations in H(2)O and D(2)O, and determined the Stokes radii and sedimentation coefficients of the HisACAT1-detergent complexes. The estimated molecular mass of HisACAT-1 is 263 kDa, which is 4 times that of the HisACAT-1 monomer (69 kDa). Finally, cross-linking experiments in intact cells and in vitro show that the increase in cross-linker concentrations causes an increase in size of the HisACAT-1-positive signals, forming material(s) 4 times the size of the monomer, supporting the conclusion that ACAT-1 is a homotetrameric enzyme.

High susceptibility of a human breast epithelial cell type with stem cell characteristics to telomerase activation and immortalization

We have recently characterized two types of normal human breast epithelial cells (HBECs) from reduction mammoplasty. Type I cells express estrogen receptor, luminal epithelial cell markers, and stem cell characteristics (i.e., the ability to differentiate into other cell types and to form budding/ductal structures on Matrigel), whereas Type II cells show basal epithelial cell phenotypes. In this study, we have examined whether Type I HBECs are more susceptible to telomerase activation and immortalization after transfection with SV40 large T-antigen. The results show that both types of cells acquire extended life span [(EL); i.e., bypassing senescence] at a comparable frequency. However, they differ significantly in the ability to become immortal in continuous culture, ie., 11 of 11 Type I EL clones became immortal compared with 1 of 10 Type II EL clones. Both parental Type I and Type II cells as well as their transformed EL clones at early passages [approximately 30 cumulative population doubling level (cpdl)] showed a low level of telomerase activity as measured by the telomeric repeat amplification protocol assay. For all 11 of the Type I EL clones and the single Type II EL clone that became immortal, telomerase activities were invariably activated at middle passages (approximately 60 cpdl) or late passages (approximately 100 cpdl). For the four Type II EL clones randomly selected from the nine Type II clones that did not become immortal, the telomerase activities were found to be further diminished at mid-passage, before the end of the life span. Thus, normal HBECs do have a low level of telomerase activity, and Type I HBECs with stem cell characteristics are more susceptible to telomerase activation and immortalization, a basis on which they may be major target cells for breast carcinogenesis.