Cell-specific localization of apolipoprotein E messenger ribonucleic acid in the testis and epididymis of the rat

Apolipoprotein (apo) E, a 35-kDa protein found on the surface of several lipoproteins, has been detected in many peripheral tissues and is postulated to function in facilitating the transfer of cholesterol/lipids between cells. We examined the expression of apo E mRNA in the testes and epididymides of juvenile rats (21 days old), prepubescent rats (34-36 days old), and sexually mature rats (75-80 days old). In situ hybridization using 35S-labeled rat apo E riboprobes was used to identify cells containing apo E mRNA. Such cells were located in the interstitial area of testes obtained from rats of all ages. This cell population consisted of primarily Leydig cells with occasional macrophages, according to immunoreactivity to 3 beta-hydroxysteroid dehydrogenase and antimacrophage antibodies, respectively. Caput epididymides obtained from sexually mature and prepubescent rats contained apo E mRNA-positive cells located in the basal region of the epididymal tubules and within the interstitial stroma. Our data are consistent with the concept that locally produced apo E plays a role in the physiologic function of the rat testis and epididymis.

A system for production of commercial quantities of human lactoferrin: a broad spectrum natural antibiotic

We previously reported the production of limited quantities of biologically active recombinant human lactoferrin in the filamentous fungus Aspergillus oryzae. In the present study, we report a modification of this production system combined with a classical strain improvement program that has enabled production of levels of recombinant human lactoferrin in excess of 2 g/l. The protein was expressed in Aspergillus awamori as a glucoamylase fusion polypeptide which was secreted into the growth medium and processed to mature human lactoferrin by an endogenous KEX-2 peptidase. The recombinant protein retains full biological activity in terms of its ability to bind iron and human enterocyte receptors. Furthermore, the recombinant protein functions as a potent broad spectrum antimicrobial protein.

Heat-inactivated Sendai virus can enter multiple MHC class I processing pathways and generate cytotoxic T lymphocyte responses in vivo

We have earlier described an alternative MHC class I processing pathway for Sendai virus (SV) in H-2Kb-transfected T2 cells (T2Kb). These cells have deleted genes for transporters associated with Ag processing (TAP1/2) and proteasome subunits LMP2/7 but can still process SV for the presentation of an immunodominant nucleoprotein CTL epitope (nucleoprotein peptide 324-332, FAPGNYPAL, SV9), even in the presence of the fungal metabolite brefeldin A (BFA). Presently we have compared live and heat-inactivated SV to investigate whether infectious virus, including early events such as binding and fusion at the host cell membrane, is important for nonclassical MHC class I processing and immunogenicity. We have found that heated virus (56 degrees C, boiled or autoclaved) with no fusion and hemagglutinin-neuraminidase activities, behaves similar to live SV in T2kb cells by entering a TAP-independent and BFA-resistant pathway. In EL-4 cells, which do not express this nonclassical TAP-independent and BFA-resistant pathway, heat-treated SV is processed in a BFA-sensitive way. In T1Kb- and TAP1/2-transfected T2Kb cells, as in T2Kb cells, processing of heat-inactivated SV was completely BFA resistant. Heat-inactivated SV was also found to prime CTLs in vivo. We conclude that heat-inactivated SV can enter both BFA-sensitive and -resistant MHC class I processing pathways and that SV in this respect may be particularly efficient. What property in the SV that is important for this characteristic is presently not clear but might be useful for the deliberate generation of CTL responses in vivo.

Mechanisms of beta 1 integrin-dependent adherence of granulocytic HL60 to fibronectin

We investigated the mechanism of beta 1 integrin-mediated adherence of stimulated granulocytic HL60 cells to fibronectin using a monoclonal antibody (15/7) that recognizes beta 1 integrins only when the receptors are active for ligand binding. Phorbol myristate acetate (PMA) stimulated expression of the 15/7 epitope on granulocytic HL60 by nearly fivefold but had an insignificant effect on the expression of the epitope on undifferentiated HL60 cells. These results paralleled the effect of PMA on HL60 and granulocytic HL60 adhesion to fibronectin, indicating that activation of beta 1 integrins is important for beta 1-mediated adherence of granulocytic HL60 cells to fibronectin. Agonists that stimulate alpha 5 beta 1-dependent human polymorphonuclear leukocyte (PMN) adhesion to fibronectin (C5a and PMA) also upregulated the 15/7 epitope on purified human PMNs. Although PMA rapidly induces increased levels of filamentous actin (F-actin) in granulocytic HL60 cells and a decrease in F-actin levels in undifferentiated HL60 cells, depolymerization of the actin cytoskeleton with cytochalasin B did not affect increased expression of the 15/7 epitope on granulocytic HL60 cells. Cytochalasin B did, however, inhibit granulocytic HL60 adherence to fibronectin by 50%, demonstrating that actin polymerization is important for optimal beta 1-dependent granulocytic adherence.

Glutathione adducts, not carbamylated lysines, are the major modification of lens alpha-crystallins from renal failure patients

alpha-Crystallins from the water-soluble and the water-insoluble, guanidine-soluble portions of lenses from four renal failure patients and two normal donors of similar age were isolated and enzymatically digested into peptides. Molecular weights of the peptides, determined by fast atom bombardment mass spectrometry, indicated modifications specifically associated with renal failure. The only modifications observed in the alpha-crystallins from renal failure patients, but not in the normal old lenses, were glutathione adducts to Cys 131 and Cys 142. These adducts were present in the lenses of all four renal failure patients, but not in the two normal old lenses. The four lenses from the renal failure patients were searched for evidence of carbamylation at lysyl or cysteinyl residues: carbamylation was not detected. Because the same mass spectrometric methods had previously demonstrated sufficient sensitivity and specificity to detect as little as 5% modification in the examination of in vitro carbamylated bovine lenses, these results indicated that carbamylation is not a major modification of the lens alpha-crystallins of renal failure patients.

[Clinicopathologic characteristics of primary liver cancer in patients younger than 35 years]

To investigate clinicopathologic characteristics of primary liver cancer (PLC) in young adults, 77 patients younger than 35 years were compared with 603 patients older than 35 years during the same period. In the young patients, PLC showed a low incidence of PLC detected at mass survey (young 15.6% versus older 28.7%, P < 0.05); a low incidence of hepatitis history (young 36.8% versus older 66.3%, P < 0.01); a high incidence of positive hepatitis B virus surface antigen (HBsAg) (young 79.2% versus older 67.6%, P < 0.05); a low incidence of associated cirrhosis (young 64.9% versus older 90.7%, P < 0.01); larger tumor size (PLC > 5cm; young 87.0% versus older 73.0%, P < 0.01); a more advanced stage of the disease in TNM classification (stage III; young 29.9% versus older 18.2%, P < 0.05). It is suggested that hepatitis B virus (HBV) may play an important role in the development of PLC without associated liver cirrhosis in the young patients. A close periodic surveillance of young adults with a positive HBsAg is important to detect PLC at an early stage.

Glycosylphosphatidylinositol-linked Db does not induce an influenza-specific cytotoxic T lymphocyte response or recycle membrane-bound peptides

Major histocompatibility complex (MHC) class I molecules, as well as MHC class I-bound peptides, are known to recycle between the cell surface and an undefined, endosomal-like compartment. Little is known about the functional significance of this process. We have explored this using two different forms of the H-2Db molecule expressed in transgenic mice, either transmembranous (Db-tm) or with a glycophosphatidylinositol (GPI)-lipid anchor (Db-GPI). The recycling capacity of peptides bound to Db-tm and Db-GPI was investigated using glycosylated Db-binding glycopeptides, which were detected by flow cytometry. Only the tm form of Db was found to readily internalize and recycle glycopeptides to the cell surface. When transgenic mice were immunized with influenza A virus (PR8) strain and tested for cytotoxic T lymphocyte (CTL) responses against an immunedominant nucleoprotein epitope (366-374, ASNENMETM), only Db-tm mice were found to generate specific CTL responses. The results support the idea that membrane recycling of MHC class I-bound peptides on antigen-presenting cells may be important for the generation of certain CTL responses.

Responses of the transmembrane potential of myocardial cells during a shock

INTRODUCTION

The purpose of this investigation was to study the transmembrane potential changes (delta Vm) during extracellular electrical field stimulation.

METHODS AND RESULTS

Vm was recorded in seven guinea pig papillary muscles in a tissue bath by a double-barrel microelectrode with one barrel in and the other just outside a cell while shocks were given across the bath. The short distance (15 to 30 microns) between the two microelectrode tips and alignment of the tips parallel to the shock electrodes eliminated the shock artifact. Following ten S1 stimuli, an S2 shock field created by a 10-msec square wave was delivered during the action potential plateau or during diastole through shock electrodes 1 cm on either side of the tissue. Four shock strengths creating field strengths of 1.7 +/- 0.1, 2.9 +/- 0.2, 6.1 +/- 0.6, and 8.8 +/- 0.9 V/cm were given for the same impalement. Both shock polarities were given at each shock strength. For shocks delivered during the action potential plateau, the magnitudes of the peak delta Vm caused by the above four potential gradients were 21.1 +/- 8.2, 33.6 +/- 13.6, 49.9 +/- 24.2, and 52.3 +/- 28.0 mV (P < 0.05 among the four groups) for the shocks causing depolarization and 37.9 +/- 14.2, 56.6 +/- 16.4, 83.1 +/- 19.4, and 92.9 +/- 29.1 mV (P < 0.05 among the four groups) for the shocks causing hyperpolarization. Though delta Vm increased as potential gradients increased, the relationship was not linear. The magnitude of hyperpolarization was 1.9 +/- 0.5 times that of depolarization when the shock polarity was reversed (P < 0.05). As potential gradients increased from 1.7 +/- 0.1 to 8.8 +/- 0.9 V/cm, the time constant of the membrane response decreased significantly from 3.5 +/- 1.8 to 1.6 +/- 0.7 msec for depolarizing shocks and from 6.0 +/- 3.1 to 3.4 +/- 1.9 msec for hyperpolarizing shocks (P < 0.01 vs depolarizing shocks). For shocks delivered during diastole, hyperpolarizing shocks induced triphasic changes in Vm during the shock, i.e., initial hyperpolarization, than depolarization, followed again by hyperpolarization.

CONCLUSION

During the action potential plateau, the membrane response cannot be represented by a classic passive RC membrane model. During diastole, activation upstrokes occur even during hyperpolarization caused by shocks creating potential gradients between approximately 2 and 9 V/cm.

[Expression of Epstein-Barr virus encoded small RNA-1 and latent membrane protein-1 in midline T-cell lymphomas]

Nine cases of midline T-cell lymphoma (MTL) were studied for expression of Epstein-Barr virus (EBV) encoded small RNA-1 (EBER-1) and EBV latent membrane protein-1 (LMP-1) using in situ hybridization and immunohistochemistry respectively. EBER-1 was detected in nuclei of tumor cells in 8/9 cases of MTL and LMP-1 was found on membrane and in cytoplasm of tumor cells in 7/9 cases of MTL. The results show: (1) There is a strong association between EBV and MTL. EBV may play an important role in the pathogenesis of MTL. (2) The detection frequency of EBV in MTL is higher than peripheral T-cell lymphoma from other sites of the body. (3) EBER-1 in situ hybridization and LMP-1 immunohistochemistry are sensitive and reliable in detection of EBV in MTL and the latter is more economic and convenient.

Heat-inactivated Sendai virus can enter multiple MHC class I processing pathways and generate cytotoxic T lymphocyte responses in vivo

We have earlier described an alternative MHC class I processing pathway for Sendai virus (SV) in H-2Kb-transfected T2 cells (T2Kb). These cells have deleted genes for transporters associated with Ag processing (TAP1/2) and proteasome subunits LMP2/7 but can still process SV for the presentation of an immunodominant nucleoprotein CTL epitope (nucleoprotein peptide 324-332, FAPGNYPAL, SV9), even in the presence of the fungal metabolite brefeldin A (BFA). Presently we have compared live and heat-inactivated SV to investigate whether infectious virus, including early events such as binding and fusion at the host cell membrane, is important for nonclassical MHC class I processing and immunogenicity. We have found that heated virus (56 degrees C, boiled or autoclaved) with no fusion and hemagglutinin-neuraminidase activities, behaves similar to live SV in T2kb cells by entering a TAP-independent and BFA-resistant pathway. In EL-4 cells, which do not express this nonclassical TAP-independent and BFA-resistant pathway, heat-treated SV is processed in a BFA-sensitive way. In T1Kb- and TAP1/2-transfected T2Kb cells, as in T2Kb cells, processing of heat-inactivated SV was completely BFA resistant. Heat-inactivated SV was also found to prime CTLs in vivo. We conclude that heat-inactivated SV can enter both BFA-sensitive and -resistant MHC class I processing pathways and that SV in this respect may be particularly efficient. What property in the SV that is important for this characteristic is presently not clear but might be useful for the deliberate generation of CTL responses in vivo.

Generation of cytotoxic and humoral immune responses by nonreplicative recombinant Semliki Forest virus

The Semliki Forest virus (SFV) expression system can be used to package recombinant RNA into infectious suicide particles. Such RNA encodes only the SFV replicase and the heterologous protein but no structural proteins of SFV, and it is thus deficient in productive replication. We demonstrate here that infection of C57BL/6 (H-2b) and BALB/c (H-2d) mice with recombinant SFV expressing the nucleoprotein (NP) of influenza virus (SFV-NP) resulted in efficient priming of influenza virus-specific CD8+ cytotoxic T-cell (CTL) responses. The generated CTLs lysed both homologous (A/PR/8/34) and heterologous (A/HK/68) influenza virus-infected, or peptide-coated, target cells to a similar degree as CTLs induced by wild-type influenza virus in a major histocompatibility complex class I-restricted fashion. As few as 100 infectious units of virus induced a strong CTL response. Induction of CTL by SFV-NP could also be achieved in CD4 gene-targeted mice, demonstrating the independence of the primary CTL response of CD4+ helper T cells. One immunization generated a CTL response that peaked after 1 week, and an additional booster injection generated a CTL memory, which was still detectable after 40 days. SFV-NP immunizations also generated high-titered IgG humoral responses that remained significant after several months. These results demonstrate that the recombinant SFV suicide system is highly efficient in antigen presentation and suggest that it may have a potential as a recombinant vaccine.

[Interference of selenium germanium and calcium in carcinogenesis of colon cancer]

We studied DMH induced colon cancer in 120 wistar rats, which were divided into 8 groups based on different diets. They were killed and autopsied on 4 weeks after the last injection of DMH. The tumors in various organs including its characteristics, number, site, histological types and ultrastructural changes were observed. The results showed that high fat diet has a significant effect on DMH induced colon cancer. Selenium and calcium can inhibit the effect of DMH and decrease the incidence of colon cancer. Selenium can also interfere the effect of high fat diet but germanium has no effect on colon carcinogenesis.

Correlation among fibrillation, defibrillation, and cardiac pacing

An electrical stimulus must create an electric field of approximately 1 V/cm in the extracellular space to stimulate myocardium during diastole. To initiate fibrillation by premature stimulation during the vulnerable period or to defibrillate, an extracellular electric field of approximately 6 V/cm is required, a value approximately six times greater than that necessary for diastolic pacing. Yet, the current strength of the pulse given to the stimulating electrode to initiate fibrillation or to defibrillate is much greater than six times the diastolic pacing threshold. The ventricular fibrillation threshold is typically 40 times greater than the diastolic pacing threshold expressed in terms of current. The defibrillation threshold in terms of current is typically thousands of times greater than the diastolic pacing threshold. The reason that these thresholds vary so much more in terms of stimulus current than in terms of extracellular potential gradient is that each of the three thresholds requires creation of the required potential gradient at different distances from the stimulating electrode. Pacing requires a potential gradient of approximately 1 V/cm only in a small liminal volume of tissue immediately adjacent to the electrode. Initiation of ventricular fibrillation by premature stimulation during the vulnerable period requires a potential gradient of approximately 6 V/cm about 1 cm away from the stimulating electrode to allow sufficient space for the central common pathway of a figure-eight reentrant circuit to form. Since the potential gradient falls off rapidly with distance from the stimulating electrode, a stimulating current about 40 times greater than the diastolic pacing threshold is required to generate an electric field of 6 V/cm approximately 1 cm away from the stimulating electrode. Defibrillation requires an electric field of approximately 6 V/cm throughout all or almost all of the ventricular myocardium. Since some portions of the ventricles can be more than 10 cm away from the defibrillation electrodes, a shock of several amps is required to create this field, a current thousands of times greater than the pacing threshold.

Changes in the serum concentrations of gonadotrophins and oestradiol in peripubertal Chinese Beijing black gilts

Four gifts of the Chinese Beijing Black breed, all from the same litter, had their blood serum concentrations of luteinizing hormone (LH), follicle stimulating hormone (FSH) and oestrogens (E2) measured by radioimmunoassay at intervals of 20 days between the ages of 5 and 185 days. The concentrations of LH declined sharply between days 5 to 25 and remained low until rising again from day 85 and reaching a peak at day 105 before declining again and remaining constant. The concentrations of FSH increased from day 85, peaking at day 105, followed by a slow decline to day 185. Serum E2 concentrations were high at day 5 then decreased dramatically, but increased considerably at 185 days. These results are similar to those reported from European breeds.

[Establishment of three-dimensional finite element models by using a series of plane section images processed with an image analysis system]

The geometric similarity and mesh dividing of finite element models directly create an effect on the results of analysis when a theoretical stress analysis is performed by the use of finite element method. The model is routinely established by means of sectioning the specimen. In this paper, a series of plane section CT images of the teeth and mandible, an image analysis system and a specially designed software for modeling three-dimensional finite element were used to establish a three-dimensional finite element model. It is a new preprocessing method for finite element applications in the field of oral biomechanism. The technique is characterized by the advantages of high similarity of the model to specimens and no damage to specimens; it is simple and easy. The images and figures can be repetitively used.

[A study on the relationship between in-door air pollution and chronic obstructive pulmonary disease in Xuanwei County]

A cross-sectional study was conducted to explore the relationship between in-door air pollution caused by different fuels for domestic use and chronic obstructive pulmonary disease (COPD) in local population. A total population of 10892 were sampled and analyzed. Results showed in-door air pollution caused by coal-burning was the major risk factor for COPD in Xuanwei County. The risk of residents using soft coal and anthracite to suffer from COPD was 4.36 and 1.55 times, respectively, higher than in those using fire wood.

[The cytopathologic diagnosis of cervical lesions and uterocervical carcinomas]

Fifty one cases of Papanicolaou grade, I, II, III and 49 of IV, V were studied for cytopathologic diagnosis in cervical and uterine curet smears. The cervical glandular erosion, metaplasia and cervical intraepithelial neoplasia, as well as histologic types of carcinomas, which were not distinguished by diagnosis of Papanicolaou grades, were determined by cytopathologic diagnosis. Therefore, the papanicolaou method of cytologic diagnosis should be gradually replaced by cytopathologic diagnosis.

[Changes in serum IL-2 and sIL-2R levels in patients with primary hepatic carcinoma before and after treatment and their clinical significance]

Serum IL-2 and sIL-2R levels were measured with sandwith ELISA assay before and after surgery or transarterial embolization in 19 cases of primary hepatic carcinoma. The results show that pretreatment IL-2 levels of patients were significantly lower and sIL-2R expression was higher than those of normal control. IL-2 levels of patient were increased and sIL-2R expression was decreased after treatment. The results suggest that the changes of IL-2 level and sIL-2R expression may be closely related to treatment, recurrence and prognosis of patients with primary hepatic carcinoma.

Effect of the modulation transfer function of a digital image-acquisition device on phase-measuring profilometry

Systematic errors in phase-measuring profilometry that are introduced by the modulation transfer function of a digital image-acquisition device are analyzed. New phase expressions and phase-deviation formulas are given. The results for simulations and experiments demonstrate that the algorithm of phase-measuring profilometry cannot be regarded as a point-to-point operation. To obtain precise results, an optimum scheme for setting the measurement system is also proposed.

Influence of cardiac output distribution on cardiac filling pressure during rest and dynamic exercise in dogs

The distribution of cardiac output (CO) between compliant and noncompliant organs is an important determinant of the slope of the relationship predicted between CO and right atrial pressure (RAP). However, curves relating CO to RAP at rest are shifted rightward (higher CO) and upward (higher RAP) by exercise with no change in slope, despite a large rise in the fraction of CO directed to noncompliant muscle vasculature, which is predicted to decrease the slope. We sought to test whether reductions in CO imposed during rest and exercise are accompanied by changes in its distribution that would favor constant slopes. Six dogs had atrioventricular block produced surgically and had blood flow transducers implanted on the ascending aorta and the terminal aorta. Total muscle blood flow (MBF) was estimated from terminal aortic flow by assuming that all of the increase in CO in mild dynamic exercise is directed to muscle. CO was reduced by lowering ventricular pacing rate at rest and during graded treadmill exercise (2 and 4 miles/h at 0% grade). Exercise increased the fraction of CO directed to muscle (MBF/CO) (P < 0.001). The effect of changes in CO on MBF/CO depended on exercise intensity (P < 0.01). At rest, MBF/CO fell from 0.53 to 0.45 when CO was reduced; this is expected to reduce the slope of the measured relationship between CO and RAP. During exercise at 2 miles/h, MBF/CO changed little when CO was reduced.(ABSTRACT TRUNCATED AT 250 WORDS)

Mammalian nonsense codons can be cis effectors of nuclear mRNA half-life

Frameshift and nonsense mutations within the gene for human triosephosphate isomerase (TPI) that generate a nonsense codon within the first three-fourths of the protein coding region have been found to reduce the abundance of the product mRNA that copurifies with nuclei. The cellular process and location of the nonsense codon-mediated reduction have proven difficult to elucidate for technical reasons. We show here, using electron microscopy to judge the purity of isolated nuclei, that the previously established reduction to 25% of the normal mRNA level is evident for nuclei that are free of detectable cytoplasmic contamination. Therefore, the reduction is likely to be characteristic of bona fide nuclear RNA. Fully spliced nuclear mRNA is identified by Northern (RNA) blot hybridization and a reverse transcription-PCR assay as the species that undergoes decay in experiments that used the human c-fos promoter to elicit a burst and subsequent shutoff of TPI gene transcription upon the addition of serum to serum-deprived cells. Finally, the finding that deletion of a 5' splice site of the TPI gene results predominantly but not exclusively in the removal by splicing (i.e., skipping) of the upstream exon as a part of the flanking introns has been used to demonstrate that decay is specific to those mRNA products that maintain the nonsense codon. This result, together with our previous results that implicate translation by ribosomes and charged tRNAs in the decay mechanism, indicate that nonsense codon recognition takes place after splicing and triggers decay solely in cis. The possibility that decay takes place during the process of mRNA export from the nucleus to the cytoplasm is discussed.

The MTS1 gene is frequently mutated in primary human esophageal tumors

Homozygous and heterozygous deletions involving chromosome 9p21 have been reported in a variety of primary human tumors in vivo, and point mutations have been reported in melanoma cell lines in vitro within a probable tumor suppressor gene, MTS1, located at chromosome 9p21. We describe six sequence alterations occurring among twenty-four primary esophageal squamous carcinomas and nineteen primary esophageal adenocarcinomas analyzed by DNA sequencing of MTS1 exon 2. Nucleotide substitutions were observed in five squamous cell carcinomas and in one adenocarcinoma. Two occurred in the germline, while four were somatic alterations. All six nucleotide changes resulted in marked alterations in amino acid sequence. Four were nonsense mutations leading to premature termination codons; nucleotide substitutions identical to two of these stop codons were previously reported in other tumor types. Loss of heterozygosity occurred in all five informative (constitutionally heterozygous) cases in which a sequence alteration was present. Esophageal cancer is one primary human tumor in which MTS1 constitutes an apparent target of heterozygous or homozygous deletions occurring at chromosome 9p21.

Self-replicating Semliki Forest virus RNA as recombinant vaccine

Recombinant RNA based on the Semliki Forest virus (SFV) replicon was used to express the nucleoprotein of influenza virus in mice. Two strategies were employed to deliver the RNA. In the first, recombinant RNA was packaged into infectious suicide SFV particles which were used directly for immunization. The second approach involved injection of in vitro-synthesized RNA directly into the quadriceps muscle. Both approaches resulted in the generation of humoral responses with high antibody titres. Immunization with suicide particles showed that a strong, class I-restricted cytotoxic T-cell response can be obtained using only 100 infectious units. We conclude that the self-replicative recombinant SFV RNA may be quite useful as a nucleic acid vaccine.