Temperature regulation of the streptococcal pyrogenic exotoxin A-encoding gene (speA)

The gene encoding the bacterial superantigen streptococcal pyrogenic exotoxin A is often found in streptococcal strains associated with the recently described streptococcal toxic shock syndrome. Here we demonstrate that this gene is expressed at approximate fourfold higher levels in cells grown at 37 degrees C when compared to cells grown at 26 degrees C. This suggests there is increased production of this toxin when Streptococcus pyogenes is found in infections of the soft tissues and bloodstream, as opposed to S. pyogenes that have not breached the epithelial layers and are living on the surface of the skin.

Computation of the full likelihood function for estimating variance at a quantitative trait locus

The proportion of alleles identical by descent (IBD) determines the genetic covariance between relatives, and thus is crucial in estimating genetic variances of quantitative trait loci (QTL). However, IBD proportions at QTL are unobservable and must be inferred from marker information. The conventional method of QTL variance analysis maximizes the likelihood function by replacing the missing IBDs by their conditional expectations (the expectation method), while in fact the full likelihood function should take into account the conditional distribution of IBDs (the distribution method). The distribution method for families of more than two sibs has not been obvious because there are n(n - 1)/2 IBD variables in a family of size n, forming an n x n symmetrical matrix. In this paper, I use four binary variables, where each indicates the event that an allele from one of the four grandparents has passed to the individual. The IBD proportion between any two sibs is then expressed as a function of the indicators. Subsequently, the joint distribution of the IBD matrix is derived from the distribution of the indicator variables. Given the joint distribution of the unknown IBDs, a method to compute the full likelihood function is developed for families of arbitrary sizes.

Langerhans cells express inducible nitric oxide synthase and produce nitric oxide

The importance of nitric oxide (NO) in mediating macrophage functions has been demonstrated, but production of this potent gas has not been examined in Langerhans cells (LC). Using murine LC purified from epidermal cell suspensions and the recently established LC-like cell line derived from newborn BALB/c epidermis (XS-52), it was shown with reverse transcriptase (RT)-PCR that inducible nitric oxide synthase (iNOS) message is present in these cells. Murine keratinocytes did not contain iNOS message. iNOS mRNA was increased in a concentration-dependent manner by lipopolysaccharide (LPS) in purified murine LC and XS-52 cells, and immunofluorescence using an antibody to iNOS revealed bright cytoplasmic staining in LPS-treated XS-52 cells. Anti-iNOS antibody brightly stained LC on human neonatal foreskin cryosections. An increase in NO production by LPS-treated XS-52 cells over 16 h, as measured by the determination of nitrite levels in culture supernatants using the Griess Reaction, was observed. Interferon-gamma (IFNgamma) did not affect NO production on its own. In the presence of LPS and IFNgamma, NO production was 3 times more than observed with LPS alone. NO production was inhibited by the NOS inhibitor L-NAME. Western blots with anti-iNOS antibody demonstrated an increase in iNOS expression in LPS-treated XS-52 cells that was suppressed by IL-10. NO produced in LC may affect LC functions such as microbicidal activity, antigen presentation, and cytotoxicity and may affect adjacent keratinocytes and melanocytes.

Using the expectation or the distribution of the identity by descent for mapping quantitative trait loci under the random model

We examine the ability of four implementations of the random model to map quantitative trait loci (QTLs). The implementations use either the expectation or the distribution of the identity-by-descent value at a putative QTL and either a 2 x 1 vector of sib-pair traits or their scalar difference. When the traits of both sibs are used, there is little difference between the expectation and distribution methods, while the expectation method suffers in both precision and power when the difference between traits is used. This is consistent with the prediction that the difference between the expectation and distribution methods is inversely proportional to the amount of information available for mapping. We find, though, that the amount of information must be very low for this difference to be noticeable. This is exemplified when both marker loci are fixed. In this case, while the expectation method is powerless to detect the QTL, the distribution method can still detect the presence (but not the position) of the QTL 59% of the time (when using trait values) or 14% of the time (when using trait differences). We also note a confounding between estimates of the QTL, polygenic, and error variance. The degree of confounding is small when the vector of trait values is used but can be substantial when the expectation method and trait differences are used. We discuss this in light of the general ability of the random model to partition these components.

Radial equilibrium lengths of actomyosin cross-bridges in muscle

Radial equilibrium lengths of the weakly attached, force-generating, and rigor cross-bridges are determined by recording their resistance to osmotic compression. Radial equilibrium length is the surface-to-surface distance between myosin and actin filaments at which attached cross-bridges are, on average, radially undistorted. We previously proposed that differences in the radial equilibrium length represent differences in the structure of the actomyosin cross-bridge. Until now the radial equilibrium length had only been determined for various strongly attached cross-bridge states and was found to be distinct for each state examined. In the present work, we demonstrate that weakly attached cross-bridges, in spite of their low affinity for actin, also exert elastic forces opposing osmotic compression, and they are characterized by a distinct radial equilibrium length (12.0 nm vs. 10.5 nm for force-generating and 13.0 nm for rigor cross-bridge). This suggests significant differences in the molecular structure of the attached cross-bridges under these conditions, e.g., differences in the shape of the myosin head or in the docking of the myosin to actin. Thus, the present finding supports our earlier conclusion that there is a structural change in the attached cross-bridge associated with the transition from a weakly bound configuration to the force-generating configuration. The implications for imposing spatial constraints on modeling actomyosin interaction in the filament lattice are discussed.

[The effects of cardioplegia and reperfusional blood containing captopril on myocardial ultrastructure alterations after cardiac arrest]

OBJECTIVE

To investigate the myocardial protective effect of captopril on the ischemia and reperfusion injury in the canine heart.

METHODS

Twelve mongrel dogs were randomly divided into control and captopril groups. In the former, only modified St. Thomas cardioplegia was used, and in the latter, modified St. Thomas cardioplegia and reperfusional blood containing 4.6mumol/L captopril were used. Sixty minutes after reperfusion, myocardial renin activity (MRA), angiotensin II (AII) and melondyldialdehyde (MDA) content in myocardium were measured, and the subendocardial myocardium of the left ventricle was taken for electromicroscopy.

RESULTS

The MRA in the Cp1 group was significantly higher than that in the control group (P < 0.01), while the AII and MDA content in the myocardium in the Cp1 group were significantly lower than those in the control group (P < 0.01). Electronmicroscopically, the damage of the myocardium including sarcomeres, mitochondria and microvascular endothelial cells were less obvious in the Cp1 group than that in the control. The mitochondrial average cross-section area and average volume (0.59 +/- 0.15 micron2 and 0.74 +/- 0.23 micron3) in the Cp1 group were significantly lower than those in the control (0.83 +/- 0.34 micron2, P < 0.01 and 1.1 +/- 0.4 micron3, P < 0.01). The numerical density (0.46 +/- 0.16 micron-3), specific surface of mitochondria (6.4 +/- 1.1 microns-1) and memberance density of mitochondrial cristae (21 +/- 10 microns-1) in the Cp1 group were significantly higher than those in the control (0.29 +/- 0.06 micron-3, P < 0.05, 4.8 +/- 0.8 micron-1, P < 0.01 and 15.3 +/- 2.0 microns-1, P < 0.01):

CONCLUSION

Cardioplegia and reperfusional blood containing 4.6 mumol/L captopril could effectively protect the myocardial mitochondria and microvascular endothelial cells against ischemia and reperfusion injury.

Twyman effect mechanics in grinding and microgrinding

In the Twyman effect (1905), when one side of a thin plate with both sides polished is ground, the plate bends: The ground side becomes convex and is in a state of compressive residual stress, described in terms of force per unit length (Newtons per meter) induced by grinding, the stress (Newtons per square meter) induced by grinding, and the depth of the compressive layer (micrometers). We describe and correlate experiments on optical glasses from the literature in conditions of loose abrasive grinding (lapping at fixed nominal pressure, with abrasives 4-400 μm in size) and deterministic microgrinding experiments (at a fixed infeed rate) conducted at the Center for Optics Manufacturing with bound diamond abrasive tools (with a diamond size of 3-40 μm, embedded in metallic bond) and loose abrasive microgrinding (abrasives of less than 3 μm in size). In brittle grinding conditions, the grinding force and the depth of the compressive layer correlate well with glass mechanical properties describing the fracture process, such as indentation crack size. The maximum surface residual compressive stress decreases, and the depth of the compressive layer increases with increasing abrasive size. In lapping conditions the depth of the abrasive grain penetration into the glass surface scales with the surface roughness, and both are determined primarily by glass hardness and secondarily by Young's modulus for various abrasive sizes and coolants. In the limit of small abrasive size (ductile-mode grinding), the maximum surface compressive stress achieved is near the yield stress of the glass, in agreement with finite-element simulations of indentation in elastic-plastic solids.

Actions of Rho family small G proteins and p21-activated protein kinases on mitogen-activated protein kinase family members

The mitogen-activated protein (MAP) kinases are a family of serine/threonine kinases that are regulated by distinct extracellular stimuli. The currently known members include extracellular signal-regulated protein kinase 1 (ERK1), ERK2, the c-Jun N-terminal kinase/stress-activated protein kinases (JNK/SAPKs), and p38 MAP kinases. We find that overexpression of the Ste20-related enzymes p21-activated kinase 1 (PAK1) and PAK2 in 293 cells is sufficient to activate JNK/SAPK and to a lesser extent p38 MAP kinase but not ERK2. Rat MAP/ERK kinase kinase 1 can stimulate the activity of each of these MAP kinases. Although neither activated Rac nor the PAKs stimulate ERK2 activity, overexpression of either dominant negative Rac2 or the N-terminal regulatory domain of PAK1 inhibits Ras-mediated activation of ERK2, suggesting a permissive role for Rac in the control of the ERK pathway. Furthermore, constitutively active Rac2, Cdc42hs, and RhoA synergize with an activated form of Raf to increase ERK2 activity. These findings reveal a previously unrecognized connection between Rho family small G proteins and the ERK pathway.

Atomic (scanning) force microscopy in cardiovascular research

The promise of atomic (scanning) force microscopy (AFM) for cardiovascular research is enormous. The AFM images by using a sharp cantilever tip to sense the repulsive and attractive forces between the tip and the sample surface. The force of interaction is kept constant while raster scanning, resulting in images of the surface contours with molecular and, on hard inorganic surfaces, even atomic resolution. Movement of the cantilever in the Z plane is detected by a laser beam reflected off the cantilever to a photodiode system, a piezotube allows an X and Y raster, and a three-dimensional image results. Its capabilities include: (1) the three-dimensional imaging of membranes and biomolecules with molecular and submolecular resolution; (2) such imaging not only of dry specimens but of specimens in a physiologic solution, thereby allowing the investigation of dynamic processes in both viable biomolecules and living cells; (3) the sensing of charge and intermolecular interaction forces; (4) the chemical or biochemical modification of the cantilever tip, which allows the identification of specific structures and the measurement of specific interactions (e.g., a ligand-receptor interaction); (5) nanometer control of the position and force of the cantilever, which, in turn, allows the physical manipulation of biomolecules, the dissection of biological structures (e.g., the separation of one gap junctional hemichannel from its neighbor, thereby revealing normally inaccessible surfaces), the delivery of ligands, drugs, or other materials to specific locations, and the precise measurement of interacting forces at specific sites; and (6) the modification of the apparatus by adding complementary methodologies (e.g., magnetic resonance imaging, fluorescence microscopy, confocal microscopy, and perhaps electrophysiology). AFM, however, is only now being applied to biological research, many technical and methodologic problems exist, and a number of them are considered in this review. Little work has been done in cardiovascular research and the purpose of this review is to introduce this new and exciting approach to investigation.

Mapping quantitative trait loci for complex binary diseases using line crosses

A composite interval gene mapping procedure for complex binary disease traits is proposed in this paper. The binary trait of interest is assumed to be controlled by an underlying liability that is normally distributed. The liability is treated as a typical quantitative character and thus described by the usual quantitative genetics model. Translation from the liability into a binary (disease) phenotype is through the physiological threshold model. Logistic regression analysis is employed to estimate the effects and locations of putative quantitative trait loci (our terminology for a single quantitative trait locus is QTL while multiple loci are referred to as QTLs). Simulation studies show that properties of this mapping procedure mimic those of the composite interval mapping for normally distributed data. Potential utilization of the QTL mapping procedure for resolving alternative genetic models (e.g., single- or two-trait-locus model) is discussed.

[Hashimoto's disease with thyroid cancer: report of six cases]

Hashimoto's disease associated with thyroid cancer is not common. From January 1976 to December 1994, a total of 95 patients with Hashimoto's disease were treated surgically. Six (5 Papillary 1 folicular) of 95 patients had thyroid cancer which was concomitantly revealed pathologically. They were all women with mean age of 30.3 years. The size of tumor was 0.3-2.0 cm. Follow-up for 1-17 years showed that they were all alive and healthy. Two patients were misdiagnosed as having anaplastic carcinoma but the definitive diagnosis by immunohistochemical analysis was thyroid malignant lymphoma (B-cell type). Hashimoto's disease and thyroid cancer relationship, diagnosis, and treatment are discussed.

The effect of granulocyte colony-stimulating factor (G-CSF) on the degranulation of secondary granule proteins from human neutrophils in vivo may be indirect

Granulocyte colony-stimulating factor (G-CSF) was administered at a dose of 7.5 or 10 micrograms/kg s.c. once daily for 6d (days 1-6) to two groups consisting of eight and six healthy volunteers. The administration of G-CSF resulted in a rapid decrease in neutrophil counts and serum levels of the secondary granule protein, human neutrophil lipocalin (HNL) after 30 min, followed by a recovery and gradual increase within 180 min. The number of circulating neutrophils and plasma and serum levels of neutrophil secondary granule proteins were dramatically elevated on day 2 (1 d after the administration of G-CSF) and stayed so until day 7. The plasma levels of HNL and lactoferrin (LF) showed a biphasic pattern with peaks at day 2 and days 5-7, and remained highly elevated at day 12. The serum levels of HNL and LF increased rapidly (about 8-fold and 6-fold, respectively) on day 2 and stayed elevated until day 7, subsequently returning to baseline levels. At day 5, neutrophil release induced in vitro by f-MLP was significantly enhanced. The cellular contents of HNL and LF were reduced to about 50% of levels before G-CSF administration at day 5. The release of lactoferrin and HNL, but not of myeloperoxidase (MPO), was slightly enhanced after preincubation of isolated normal neutrophils with G-CSF in vitro, but no obvious release of these proteins was observed with G-CSF alone. The administration of G-CSF resulted in a dramatic increase in the alkaline phosphatase (AP) activity in the plasma membrane, with maximal activity occurring at day 5. Furthermore, during administration of G-CSF, TNF-alpha in plasma increased about 25-fold. TNF-alpha started to rise at day 2 and peaked at day 6. After discontinuation of G-CSF the levels of TNF-alpha gradually decreased. The elevated levels of TNF-alpha (tumour necrosis factor-alpha) were temporally correlated to the other signs of neutrophil activation. GM-CSF and IL-8, however, were not detected in plasma. Our data suggest that G-CSF affects the neutrophils not only directly but also indirectly by the induction of the production of other cytokines such as TNF-alpha.

[The value of determining guanine deaminase in diagnosis of hepatic diseases]

We determined the Guanine Deaminase (GD) activity of 200 patients with different diseases. It was found that GD activity of hepatic patients is higher than that of health adults, while the GD activity of other patients is in the normal range. There is a linear correlation between GD activity and ALT in patients with chronic hepatitis, billiary obstruction, and between GD activity and total bilirubin in patients with chronic active hepatitis, biliary obstruction and liver cirrhosis. Moreover, the GD activity of patients positive for anti-HCV is significantly increased. So GD activity in serum is a specific and sensitive index to estimating hepatic functions and can be used in the diagnosis of acute and chronic hepatitis, cirrhosis of liver, and C virus hepatitis.

Identification of a fibronectin-binding protein (GfbA) in pathogenic group G streptococci

Attachment to eukaryotic cell surfaces is an essential step in the establishment of colonization and infection by bacterial pathogens. This report examines the adherence capabilities of pathogenic group G streptococci and demonstrates that certain group G streptococcal clinical isolates express a fibronectin-binding protein. This protein, termed GfbA for group G streptococcal fibronectin-binding protein, mediates adherence to human skin fibroblasts (HSF). The gene encoding this protein, gfbA, was isolated, and the complete DNA sequence of gfbA was determined. From this sequence GfbA was predicted to be a 580-amino-acid protein (molecular weight = 64,979) with significant amino acid identity to the group A streptococcal fibronectin-binding proteins SfbI and protein F (PrtF) (76 and 78% identity, respectively). GfbA contains regions with notable identity to the fibronectin-binding repeat domains of PrtF. gfbA(+) strains were able to bind to HSF, and preincubation of the gfbA(+) strains with fibronectin blocked this adherence. In addition, gfbA(+) strains were able to bind radiolabeled fibronectin, and this binding was inhibited with addition of excess unlabeled fibronectin. gfbA-negative strains were not able to bind either the HSF or radiolabeled fibronectin. DNA homologous to gfbA was found in 36% of the group G streptococcal isolates examined. Since not all group G streptococcal strains examined contained gfbA, this suggests there might be other tissue-specific adherence molecules expressed by these pathogenic strains.

Cloning of rat MEK kinase 1 cDNA reveals an endogenous membrane-associated 195-kDa protein with a large regulatory domain

The coding sequence of rat MEK kinase 1 (MEKK1) has been determined from multiple, independent cDNA clones. The cDNA is full-length based on the presence of stop codons in all three reading frames of the 5' untranslated region. Probes from the 5' and the 3' coding sequences both hybridize to a 7-kb mRNA. The open reading frame is 4.5 kb and predicts a protein with molecular mass of 161,225 Da, which is twice the size of the previously published MEKK1 sequence and reveals 801 amino acids of novel coding sequence. The novel sequence contains two putative pH domains, two proline-rich regions, and a cysteine-rich region. Antisera to peptides derived from this new sequence recognize an endogenous protein in human and rodent cells of 195 kDa, consistent with the size of the expressed rat MEKK1 clone. Endogenous and recombinant rat MEKK1 are enriched in membranes; little of either is found in soluble fractions. Expression of recombinant rat MEKK1 leads to activation of three mitogen-activated protein kinase modules in the order c-Jun N-terminal kinase/stress-activated protein kinase > p38 mitogen-activated protein kinase = extracellular signal-regulated kinase 2.

Molecular cloning and functional characterization of a rat pituitary G protein-coupled adenosine triphosphate (ATP) receptor

There is increasing evidence that pituitary ATP receptors may play a novel role in modulating pituitary function. This work reports the isolation and expression of a pituitary ATP receptor gene clone from a rat pituitary complementary DNA library. The isolated clone (rpP2U) has a 1125-bp coding sequence flanked by 483 bp of 5' - and 422 bp of 3'-untranslated sequences. The deduced 374-amino acid product shows structural features common to other G protein-coupled receptors, and when stably transfected into a glioma cell line lacking endogenous ATP receptors, is functionally characterized as a P2U purinoceptor. Specifically, the ATP-induced intracellular Ca2+ mobilization in the transfected cells was inhibited by suramin, 2-methylthio-ATP had a modest stimulatory effect on intracellular Ca2+ mobilization, and beta, gamma-methylene ATP and alpha, beta-methylene ATP had no effect. The cloned receptor exhibited the agonist potency and efficacy profile of ATP approximately equal to uridine triphosphate > ADP approximately equal to uridine diphosphate > GTP. Such characteristics very closely mimic the pharmacologically defined P2U purinoceptor of primary rat gonadotropes and mixed sheep pituitary cells, and Southern blot analysis further indicates that there is only one allele in rat genome for the P2U purinoceptor. These findings suggest that the P2U purinoceptor is the predominant G protein-linked ATP receptor found in the pituitary.

UVB radiation interrupts cytokine-mediated support of an epidermal-derived dendritic cell line (XS52) by a dual mechanism

We have established long-term dendritic cell lines from the epidermis of newborn mice. These cell lines (XS series) proliferate maximally in response to granulocyte/macrophage-colony stimulating factor, as well as to CSF-1, which is produced by skin-derived NS fibroblast lines and by keratinocytes (albeit in smaller amounts). The purpose of this study was to examine the impact of UVB radiation on CSF-1-mediated interaction of dendritic cells with fibroblasts and keratinocytes. Exposure of NS cells to UVB radiation (unfiltered FS20 sunlamp) decreased CSF-1 production at mRNA and protein levels. Both changes occurred in a dose-dependent fashion, with 50 J/m2 causing a significant reduction. UVB radiation also downregulated CSF-1 mRNA expression by Pam 212 keratinocytes. UVB exposure of XS cells diminished the surface expression of CSF-1 receptors, with 50 J/m2 causing a significant reduction. Thus, UVB radiation interrupts CSF-1-mediated cell-cell interaction by a dual mechanism: downregulating CSF-1 production and abrogating CSF-1 receptor expression. Importantly, granulocyte/macrophage-colony stimulating factor receptor expression by XS cells was also inhibited by UVB radiation, once again, with 50 J/m2 producing significant inhibition. We propose that the resulting CSF-1 deficiency in epidermal microenvironment and unresponsiveness by dendritic cells to relevant growth factors may contribute to UVB-mediated loss of resident epidermal dendritic cells (i.e., Langerhans cells) in skin.

[Extremity gangrene caused by rare co-infection of multiple bacteria: a case report]

Because of progressive infectious necrosis on right hand and forearm for 3 months and the necrosis on left mid-finger for 2 months, a girl patient, Yang Xiaoxia was admitted on 15th, Nov. 1994. Systemic intoxicative symptom was slight and the necrotic tissue presented black scar. After 3 months treatment by application of multiple antibiotics, local dressing changes and an amputation of right froearm, the necrosis could not be stopped but keeping deteriorating. Through experts' consultation, systemic surpportive therapy, wide-spectrum antibiotics cilastatin sodium and complete debridement were adopted. One week later, the fresh surface of granulation tissue was seen, and skin grafting was performed. The wound healed 3 months later. After further rehabilitation, the left thumb, index and fifth finger showed normal function. A mechanical motional artificial limb was installed on right forearm and discharged. The deep necrotic tissue of left mid-finger was examined. Results of culture from several hospital presented 2 kinds of aerobic bacteria and 10 kinds of the anaerobic, of which, the names of 3 kinds are still unknown. Pathological examination showed chronic pyogenic necrotic infection, spreading from skin to deep muscles and interosseous membrane. And infiltration of eosinophilic granulocytes was found in the infectious region.

CONCLUSION

This patients is progressive gangrene of the extremity caused by rare co-infection of multiple bacteria. The characteristics were slight systemic intoxicative symptom, local progressive necrosis and formation of black scar. By means of systemic surpportive therapy, application of wide-spectrum antibiotics cilastatin sodium, complete debridement and skin grafting, the patient was cured.

7-Nitroindazole attenuates vasodilation from cerebellar parallel fiber stimulation but not acetylcholine

We used the relatively selective inhibitor of neuronal nitric oxide synthase 7-nitroindazole (7-NI) to test the hypothesis that the increases in local cerebellar blood flow (BFcrb) elicited by activation of the cerebellar parallel fibers (PF) are mediated by neuronal production of nitric oxide. In halothane-anesthetized rats, the cerebellar cortex was exposed and superfused with Ringer solution (37 degrees C; pH 7.3-7.4). The PF were stimulated electrically (100 microA, 30 Hz, 40 s), while BFcrb was monitored at the site of stimulation by a laser-Doppler flow probe. In vehicle-treated rats (n = 5), PF stimulation increased BFcrb by 61 +/- 5% (P < 0.05; analysis of variance and Tukey's test). 7-NI attenuated the increase in BFcrb dose dependently (10-100 mg/kg i.p.; n = 5 animals/dose) and by 55 +/- 7% at 100 mg/kg (P < 0.05). The attenuation of the response to PF stimulation was correlated with the degree of inhibition of calcium-dependent brain nitric oxide synthase activity, measured ex vivo by the citrulline assay (n = 21). 7-NI also attenuated the cerebrovasodilation elicited by hypercapnia (PCO2 = 50-60 mmHg) but did not affect the vasodilation evoked by acetylcholine (10 microM; n = 4; P > 0.05; t-test), a response mediated by endothelial nitric oxide synthase. 7-NI did not attenuate the BFcrb increase evoked by the nitric oxide donor S-nitroso-N-acetylpenicillamine (1 mM; n = 5; P > 0.05; t-test). Similarly, 7-NI did not affect resting systemic arterial pressure. These observations suggest that selective inhibition of neuronal nitric oxide synthase by 7-NI attenuates the increases in BFcrb evoked by PF stimulation. The findings provide additional support to the hypothesis that the increase in BFcrb evoked by PF stimulation is mediated, in part, by glutamate-induced activation of neuronal nitric oxide synthase.

Scleroderma fibroblast phenotype is modulated by endothelial cell co-culture

OBJECTIVE

We established a co-culture system to investigate endothelial cell-fibroblast interaction in scleroderma (systemic sclerosis, SSc). Such a system allows reciprocal interaction between these cells. The pattern of phenotypic modulation for normal and SSc fibroblasts in co-culture was compared.

METHODS

A virally transformed human umbilical vein endothelial cell (HUVEC) derived cell line (1E-7) was cultured on nitrocellulose membrane inserts above dermal fibroblast monolayers. The effect of co-culture on fibroblast number, [3H]-thymidine ([3H]-TdR) incorporation, and collagen (type I) production were compared for 10 SSc and 5 control cell lines. Co-culture with the epithelial lines A549 and A431, and nontransformed HUVEC, was also investigated.

RESULTS

We observed a statistically significant increase in cell number and a reduction in collagen production for SSc, but not control, fibroblasts co-cultured with endothelial cells. This co-culture also promoted [3H]-TdR incorporation in both SSc and control fibroblasts. While epithelial cell lines did not influence fibroblast cell number, collagen production by SSc fibroblasts was diminished by A549.

CONCLUSIONS

Endothelial cell derived soluble factors modulated fibroblast properties in co-culture, and the different response of SSc compared with normal fibroblasts provides further evidence for a link between endothelial and fibroblast dysfunction in this disease. However, similar effects on SSc fibroblast collagen production were also observed for some epithelial cells, suggesting that modulation of fibroblast properties is not restricted to cells of endothelial origin.

Variable expressivity in a Japanese family with autosomal dominant retinitis pigmentosa closely linked to chromosome 19q

OBJECTIVE

To describe the clinical features of a Japanese family with autosomal dominant retinitis pigmentosa, the locus of which has been mapped on chromosome 19q.

DESIGN

Ophthalmologic testing, including visual acuity, slit-lamp biomicroscopy, and fundus examinations, for all family members examined. Selected members underwent kinetic visual field testing, electroretinography, and fluorescein angiography.

PATIENTS

Eleven symptomatic members, two asymptomatic obligate carriers, and nine nonaffected members in four generations of a single family with autosomal dominant retinitis pigmentosa.

RESULTS

Asymptomatic carriers showed mildly affected fundus and fluorescein angiographic images. Visual field testing disclosed restricted central and midperipheral fields. Electroretinograms disclosed reduced amplitudes of rod-isolated responses in both of these family members, indicating functional abnormalities.

CONCLUSION

Marked variability in expressivity of the retinitis pigmentosa phenotype was found in a family with autosomal dominant retinitis pigmentosa linked to chromosome 19q.

Neural mechanisms of blood flow regulation during synaptic activity in cerebellar cortex

1. We investigated the neural mechanisms of the increases in blood flow produced by synaptic activity using the parallel fiber (PF) system of the cerebellum as a model. The midline cerebellum was exposed in anesthetized rats and the PFs were stimulated with tungsten microelectrodes. Cerebellar blood flow (BFcrb) was recorded using a laser-Doppler probe, whereas field potentials were recorded using glass micropipettes. PF stimulation produced increases in BFcrb that were related to the frequency and intensity of stimulation (+60 +/- 9%, mean +/- SE, at 100 microA and 30 Hz; n = 6). The greatest increases were confined to a band stretching along the major axis of the stimulated folium and corresponding to the beam of activated PFs. The increase in evoked by PF stimulation was associated with a corresponding increase in glucose utilization, assessed by the 2-deoxyglucose method. The increases in BFcrb and the field potentials evoked by PF stimulation were abolished by tetrodotoxin (1 microM; n = 6). Ringer solution containing 12 mM Mg2+ and 0 mM Ca2+ blocked synaptic activity in the PFs and abolished the increases in flow (P > 0.05 from baseline; n = 5). The broad-spectrum glutamate receptor antagonist kynurenate (5 mM) prevented depolarization of Purkinje cells and interneurons and abolished the increase in BFcrb evoked by PF stimulation (P > 0.05; n = 6). Treatment with tetrodotoxin, Mg2+, or kynurenate did not affect the increase in BFcrb elicited by systemic hypercapnia or by topical application of the nitric oxide donor 3-morpholino sydnonimine (P > 0.05 from Ringer solution). We conclude that the increases in flow produced by synaptic activity are linked to glutamate-induced depolarization of Purkinje cells and interneurons. These findings provide evidence that activation of glutamate receptors participates in the mechanisms of functional hyperemia, and they support the validity of the PF system as a model for study of the relationship between synaptic activity and blood flow in the CNS.

[Establishment and characterization of a model of highly metastatic human ovarian cancer transplanted subcutaneously into nude mice]

A model of highly metastatic human ovarian cancer transplanted subcutaneously into nude mice was established (NMSO). Although the NMSO transplanted tumors were passaged 23 times, they retained their highly metastatic behavior. A total of 57 adult Balc/c nude mice (8-14 weeks old) were inoculated (SC) with tumor, the transplantations were 100% successful and the average survival period was 159.9 days. 47 mice were dissected and 42 mice were found to have metastatic tumors. The earliest appearance of metastasis was 56 dys. 18 male nude mice all had metastasis. Histology and ultrastructure showed that the metastatic tumors retained their malignant features and secreting function of the original poorly differentiated human ovarian serous papillary cystadenocarcinoma. FCM analysis gave a 1.4 DNA index and the chromosome mode number was 54 (hyper-diploid), exhibiting the features of human carcinoma. The detection of correlative label material showed that most cancer cells were ER and PR positive. The use of NMSO model may lead to better understanding of the mechanism of metastasis and help search for anti-metastatic agents.

13C-methacetin breath test parameter S for liver diseases diagnosis

The mechanism of 13C-methacetin breath test is set forth clearly with the analysis of pharmacokinetics mode, and the measuring method of 13C-methacetin breath test and its clinical applications in the diagnosis of liver diseases are reported in detail. On the basis of comprehensive analysis of the clinical test data, the advanced diagnostic parameter S is of important significance for the application and development of breath test.

Identification of scavenger receptor SR-BI as a high density lipoprotein receptor

High density lipoprotein (HDL) and low density lipoprotein (LDL) are cholesterol transport particles whose plasma concentrations are directly (LDL) and inversely (HDL) correlated with risk for atherosclerosis. LDL catabolism involves cellular uptake and degradation of the entire particle by a well-characterized receptor. HDL, in contrast, selectively delivers its cholesterol, but not protein, to cells by unknown receptors. Here it is shown that the class B scavenger receptor SR-BI is an HDL receptor. SR-BI binds HDL with high affinity, is expressed primarily in liver and nonplacental steroidogenic tissues, and mediates selective cholesterol uptake by a mechanism distinct from the classic LDL receptor pathway.

Altered insulin-like growth factor-II (IGF-II) level and IGF-binding protein-3 (IGFBP-3) protease activity in interstitial fluid taken from the skin lesion of psoriasis

In the present study, we have investigated insulin-like growth factors (IGFs) and their binding proteins (IGFBPs) in serum and artificially raised blister fluid from uninvolved and involved areas of nine patients with psoriasis. Both levels of IGFs and IGFBP-3, and profiles of IGFBP in serum and fluid from the uninvolved areas of these patients were comparable to those seen in normal subjects. In fluid from the involved areas, the IGF-II but not IGF-I level was significantly elevated. Among five molecular forms of IGFBP, the density of 41.5- and 38.5-kDa forms of IGFBP-3 were apparently increased in fluid from the involved areas, shown by Western ligand blotting. Radioimmunoassay further showed that the IGFBP-3 concentration in the involved areas was significantly raised. Immunoblotting revealed that the predominant form of IGFBP-3 in fluid from the uninvolved areas was a 29-kDa proteolytically modified product. In contrast, intact doublet IGFBP-3 was the main form of IGFBP-3 in fluid from the involved areas. Fluid from the involved areas but not the matched serum concentration-dependently inhibited the degradation of 125I-labeled nonglycosylated IGFBP-3 (ngIGFBP-3) caused by fluid from the uninvolved areas, suggesting the presence of an IGFBP-3 protease inhibitor(s) in psoriatic skin lesion. These findings suggest that the alterations in IGF/IGFBP system may contribute to the pathogenesis of psoriasis.

Lysis of adult ventricular myocytes by cells infiltrating rejecting murine cardiac allografts

BACKGROUND

Immunologic mechanisms that mediate myocardial cell injury during rejection are not fully understood. We therefore investigated whether cells that infiltrate rejecting cardiac allografts are capable of directly injuring myocytes and whether this injury resembles that produced by cytotoxic T lymphocytes (CTLs) that are generated in a mixed lymphocyte reaction (MLR).

METHODS AND RESULTS

Heart-infiltrating cells (HICs) were isolated from murine heterotopic BALB/c cardiac allografts undergoing rejection 6 to 8 days after transplantation into C57BL/6 mice. An in vitro model system of cultured adult murine ventricular myocytes was developed to facilitate investigation of cell-mediated myocyte injury. Isolated adult myocytes were incubated with either HICs or MLR effector cells, and myocyte death was quantified by counting the number of rod-shaped myocytes excluding trypan blue. The frequency of donor-reactive CTLs was similar in the HIC and MLR populations, as assessed by limiting dilution analysis. However, HICs were less efficient at killing donor-strain myocytes than were MLR cells. CTL-mediated cell lysis occurred by 6 hours, whereas myocyte injury produced by HICs was more gradual, with considerable cytotoxicity occurring between 12 and 24 hours. Furthermore, whereas MLR cells lysed only donor-strain myocytes, HIC lysed donor, third-party, and syngeneic myocytes. Treatment of MLR cells and HICs with anti-CD8 antibody plus complement produced a much greater inhibition of MLR cytotoxicity than of HIC cytotoxicity.

CONCLUSIONS

These data demonstrate that only a small component of myocyte injury mediated by allograft-infiltrating cells can be ascribed to CTLs within the infiltrating cell population. These findings suggest that cell types associated with a delayed-type hypersensitivity response, as well as CTLs, cause myocyte injury during cardiac rejection.

Correlated flow cytometric analysis of H-ras p21 and DNA ploidy in acute myelogenous leukemia

The flow cytometric immunoassay was used to study the correlation between the H-ras oncogene product p21 and the DNA ploidy in 30 de novo cases of acute myelogenous leukemia (AML). The results showed that 17 cases were negative for p21 expression and 13 positive for p21. The patients with positive p21 had higher percentage of bone marrow and peripheral blasts and lower peripheral leukocyte count. The expression of p21 had no influence on the therapeutic effect. Before treatment, DNA diploidy occurred in 18 cases including 13 p21 negative ones, and DNA aneuploidy was revealed in 12 cases including 8 p21 positive ones. Patients with positive p21 or having aneuploidy in complete remission were at risk for early relapse. Our results suggest that p21 may be involved in the process of leukemogenesis and progression in AML.

Effects of extracellular nucleotides in the pituitary: adenosine triphosphate receptor-mediated intracellular responses in gonadotrope-derived alpha T3-1 cells

We have recently identified gonadotropes as target cells for ATP action via ATP receptors of the P2U subtype. The present studies have used gonadotrope-derived alpha T3-1 cells to examine the possible signaling mechanisms subserving ATP action in gonadotropes. Addition of ATP produced a biphasic intracellular Ca2+ (Ca2+i) response: a transient spike followed by a small plateau. Removal of extracellular Ca2+ or depolarization with KCl abolished the plateau but had no effect on the spike. The plateau was also blocked by cadmium or nifedipine but not nickel. Pretreatment with GnRH or thapsigargin but not ryanodine inhibited the subsequent Ca2+i response to ATP. Pertussis toxin had no effect on ATP-induced Ca2+i response, whereas the phospholipase C inhibitor U73122 reduced the response. These observations suggest that the Ca2+i response is mediated by a pertussis toxin-insensitive and phospholipase C-coupled G-protein and reflects Ca2+ release from the GnRH- and thapsigargin-sensitive Ca2+ pool followed by Ca2+ influx through high voltage-gated Ca2+ channels. Activation of these ATP receptors had no apparent effects on the cAMP and cGMP signaling systems. Treatment with ATP-gamma S caused the translocation of protein kinase C (PKC) epsilon but not PKC zeta and PKC alpha to the particulate fraction. These data not only characterize the ATP receptor-mediated intracellular signaling in alpha T3-1 cells and render further evidence for a mediator role for nucleotides in gonadotrope function but also provide the first direct demonstration of PKC translocation by ATP receptors.

Phenotypic and functional heterogeneity among murine epidermal-derived dendritic cell clones

We have established recently long-term dendritic cell lines from the epidermis of newborn BALB/c mice. These lines, termed XS series, resembled epidermal resident Langerhans cells or their progenitors in terms of surface phenotype, antigen-presenting capacity, and growth factor requirement. We examined in this study the degree of clonal heterogeneity among XS cells with respect to each of these features. Twelve stable clones were established by limiting dilution microculture from 8-10-week-old cultures of the XS52 or XS20 line. Despite the uniform expression of CD45, these clones varied substantially in their expression of Ia, B7-1, and B7-2 molecules. They also varied significantly in their relative efficiency in activating T cells. Finally, remarkable clone-to-clone heterogeneity was also observed in their growth factor responsiveness; some clones responded equally well to granulocyte macrophage-colony-stimulating factor-1, whereas others responded preferentially to one or the other of these factors. We propose that the observed clonal heterogeneity in XS cells reflects possible heterogeneity in the state of maturation and mitotic potential among the starting populations, i.e., skin-associated dendritic cells in newborn mice.

[Functional rehabilitation of the urinary bladder after transection of cauda equina]

12 dogs were divided into three groups of L4 root crossover anastomosis S2 root, sacral root free anastomosis and control. All dogs received urodynamic test before and after operation and before sacrifice. The results of cystometry demonstrated the detrusor reflex had returned 7 months after operation in two groups of nerve renovation. The characteristics of axonal regeneration were revealed by immunohisto-cytochemistry and the count of nerve fibres numbers was compared with that by morphometric analysis in proximal and distal end of anastometric stoma. The comparison displayed a significant difference between nerve anastomosis groups and control group. Neural tracing study with horseradish peroxidase (HRP) in two dogs with the operation of L4 crossover S2 showed that lumbar somatic motor axons had regenerated successfully into the bladder and replaced previous sacral parasym-pathetic. Urethral sphincter function was still poor and urethral pressure was not changed post-operatively, though the electromyograme showed some improvement. The method of lumbar root or free sacral root anastomosis with sacral root is practicable for restoration of bladder function.

Isolation of MEK5 and differential expression of alternatively spliced forms

The prototype mitogen-activated protein (MAP) kinase module is a three-kinase cascade consisting of the MAP kinase, extracellular signal-regulated protein kinase (ERK) 1 or ERK2, the MAP/ERK kinase (MEK) MEK1 or MEK2, and the MEK kinase, Raf-1 or B-Raf. This and other MAP kinase modules are thought to be critical signal transducers in major cellular events including proliferation, differentiation, and stress responses. To identify novel mammalian MAP kinase modules, polymerase chain reaction was used to isolate a new MEK family member, MEK5, from the rat. MEK5 is more closely related to MEK1 and MEK2 than to the other known mammalian MEKs, MKK3 and MKK4. MEK5 is thought to lie in an uncharacterized MAP kinase pathway, because MEK5 does not phosphorylate the ERK/MAP kinase family members ERK1, ERK2, ERK3, JNK/SAPK, or p38/HOG1, nor will Raf-1, c-Mos, or MEKK1 highly phosphorylate it. Alternative splicing results in a 50-kDa alpha and a 40-kDa beta isoform of MEK5. MEK5 beta is ubiquitously distributed and primarily cytosolic. MEK5 alpha is expressed most highly in liver and brain and is particulate. The 23 amino acids encoded by the 5' exon in the larger alpha isoform are similar to a sequence found in certain proteins believed to associate with the actin cytoskeleton; this alternatively spliced modular domain may lead to the differential subcellular localization of MEK5 alpha.

Role of nitric oxide and acetylcholine in neocortical hyperemia elicited by basal forebrain stimulation: evidence for an involvement of endothelial nitric oxide

We examined the role of acetylcholine and nitric oxide in the increases in cerebrocortical blood flow elicited by stimulation of a region of the basal forebrain from which the major cholinergic projection to the cerebral cortex originates. In halothane-anesthetized rats a 3 x 3 mm area of the parietal cortex was exposed and the site was superfused with Ringer (37 degrees C; pH 7.3-7). Cortical blood flow was monitored at the site of superfusion by laser-Doppler flowmetry. The basal forebrain was stimulated electrically (100 microA; 50 Hz) and stimulated sites were histologically verified at the end of the experiment. With Ringer superfusion (n = 8), basal forebrain stimulation increased neocortical flow by 185 +/- 9% (mean +/- S.E.M.). The flow increase was attenuated (-38 +/- 6%; n = 5) by superfusion with the muscarinic cholinergic antagonist atropine (100 microM). Superfusion with atropine plus the nicotinic antagonist mecamylamine (100 microM) did not attenuate the response further (P > 0.05 from atropine alone; n = 6). Superfusion with the nitric oxide synthase inhibitor nitro-L-arginine, but not with the inactive isomer nitro-D-arginine (n = 6), attenuated the vasodilation in a dose-dependent fashion (-43 +/- 4% at 1 mM; n = 7) and reduced nitric oxide synthase catalytic activity at the site of superfusion by 95 +/- 4%. Co-application of nitro-L-arginine and atropine did not attenuate the vasodilation further (P > 0.05 from nitro-L-arginine alone; n = 6). Administration of the somewhat selective inhibitor of neuronal nitric oxide synthase 7-nitroindazole (50 mg/kg, i.p.) attenuated the increases in flow produced by topical application of N-methyl-D-aspartate (40 microM; n = 5) or by hypercapnia (n = 7), but did not affect the vasodilation produced by basal forebrain stimulation (n = 5) and by topical application of acetylcholine (10 microM; n = 5). 7-nitroindazole reduced constitutive nitric oxide synthase enzymatic activity in forebrain by 72 +/- 3% (n = 8). The data suggest that the neocortical vasodilation elicited by basal forebrain stimulation is, in part, mediated by local release of acetylcholine which, in turn, leads to increased nitric oxide synthesis in endothelial cells.

Heterozygosity of F2 from two segregating populations

Exact formulas that predict the average inbreeding coefficient and heterozygosity of an F2 generation derived from two segregating populations were developed. When population sizes are sufficiently large, the heterozygosity of the F2 is one-half of the heterozygosity of F1 plus one-half of the mean heterozygosity of the two parental populations. The importance of inferring heterozygosity of F2 is discussed from evolutionary perspective.

Age-related CNS disorder and early death in transgenic FVB/N mice overexpressing Alzheimer amyloid precursor proteins

Transgenic FVB/N mice overexpressing human (Hu) or mouse (Mo) Alzheimer amyloid precursor protein (APP695) die early and develop a CNS disorder that includes neophobia and impaired spatial alternation, with diminished glucose utilization and astrogliosis mainly in the cerebrum. Age at onset of neophobia and age at death decrease with increasing levels of brain APP. HuAPP transgenes induce death much earlier than MoAPP transgenes expressed at similar levels. No extracellular amyloid was detected, indicating that some deleterious processes related to APP overexpression are dissociated from formation of amyloid. A similar clinical syndrome occurs spontaneously in approximately 20% of nontransgenic mice when they reach mid- to late-adult life, suggesting that APP overexpression may accelerate a naturally occurring age-related CNS disorder in FVB/N mice.

A random model approach to interval mapping of quantitative trait loci

Mapping quantitative trait loci in outbred populations is important because many populations of organisms are noninbred. Unfortunately, information about the genetic architecture of the trait may not be available in outbred populations. Thus, the allelic effects of genes can not be estimated with ease. In addition, under linkage equilibrium, marker genotypes provide no information about the genotype of a QTL (our terminology for a single quantitative trait locus is QTL while multiple loci are referred to as QTLs). To circumvent this problem, an interval mapping procedure based on a random model approach is described. Under a random model, instead of estimating the effects, segregating variances of QTLs are estimated by a maximum likelihood method. Estimation of the variance component of a QTL depends on the proportion of genes identical-by-descent (IBD) shared by relatives at the locus, which is predicted by the IBD of two markers flanking the QTL. The marker IBD shared by two relatives are inferred from the observed marker genotypes. The procedure offers an advantage over the regression interval mapping in terms of high power and small estimation errors and provides flexibility for large sibships, irregular pedigree relationships and incorporation of common environmental and fixed effects.