Pathogenesis of Acanthamoeba keratitis: carbohydrate-mediated host-parasite interactions

Acanthamoeba keratitis is a sight-threatening corneal infection. In a recent study, the saccharide mannose has been shown to inhibit the binding of Acanthamoeba organisms to the epithelium of the cornea (L. D. Morton, G. L. McLaughlin, and H. E. Whiteley, Infect. Immun. 59:3819-3822, 1991). In an attempt to determine the molecular mechanism by which acanthamoebae adhere to the surface of the cornea, the present study was designed to determine whether Acanthamoeba castellanii derived from an infected human cornea (i) binds to mannose-containing glycoproteins (mannose-GPs) of corneal epithelium and (ii) expresses one or more mannose-binding proteins. Mannose-GPs of primary cell cultures of rabbit corneal epithelium were isolated by using three different agarose-conjugated, mannose-specific lectins. By electrophoresis blot-overlay assays, 35S-labeled acanthamoebae were shown to bind to mannose-GPs of corneal epithelium and to a neoglycoprotein, mannose-bovine serum albumin (mannose-BSA). 35S-labeled acanthamoebae also bound to microtiter wells coated with mannose-BSA in a concentration-dependent manner. The binding of amoebae to mannose-GPs was blocked by free methyl-alpha-D-mannopyranoside. The parasites did not bind to galactose-BSA or to many other proteins lacking mannose residues. A membrane-associated mannose-binding protein (136 kDa) of A. castellanii was isolated by affinity chromatography of detergent extracts of unlabeled parasites and of cell surface biotin-labeled parasites on a p-aminophenyl alpha-D-mannopyranoside-agarose column. The affinity-purified protein of the amoeba was shown to bind specifically to mannose-BSA. In summary, a mannose-binding protein is present on the surface membranes of Acanthamoeba, and corneal epithelial cells express Acanthamoeba-reactive GPs. One of the mechanisms of Acanthamoeba adhesion to the corneal surface may involve interactions between the mannose-binding protein of Acanthamoeba and mannose-GPs on the surface of corneal epithelium.

Electrochemical and histomorphometric evaluation of the TiNiCu shape memory alloy

By means of electrochemical and quantitative histomorphometric methods, the corrosion resistance and tissue biocompatibility of Ti50Ni50 and Ti50Ni50-xCux (x = 1, 2, 4, 6, 8) were investigated. It is discovered that the repassivation potential of Ti50Ni50-xCux (x = 2, 4, 6, 8) alloys is about 200 mV higher than that of Ti50Ni50 alloy. Namely, the addition of Cu raises the repassivation potential of TiNi shape memory alloys and improves their corrosion resistance. Pitting potentials of Ti50Ni50 and Ti50Ni50-xCux (x = 1, 2, 4, 6, 8) alloys increase with solution pH value, but the repassivation potentials keep constant. The adding of Cu has no obvious influence on pitting potential (Epit) of TiNi alloys, meanwhile, the corrosion potential and corrosion rate of Ti50Ni50-xCux (x = 1, 2, 4, 6, 8) alloys are irrelevant to its Cu content and the values are almost the same as those of TiNi alloys. The connective tissue layer covering the plates is statistically significantly thicker for Ti50Ni42Cu8 plates (p < 0.05) than that of Ti50Ni50, Ti50Ni48Cu2, Ti50Ni44Cu6 plates after one month. The numbers of connective tissue cells, polynucleated cells, macrophages and round cells are higher for Ti50Ni42Cu8 plates than those of the other three types of plates, but no statistically significant differences are detected. There are no significant differences on tissue reaction parameters after two and three months among four alloys. After one, two and three months implantation, no corrosion is observed on the plates surfaces. A preliminary conclusion can be drawn that Ti50Ni50-xCux (x = 2, 6, 8) shape memory alloys have good biocompatibility.

Homogeneous nucleation in sickle hemoglobin: stochastic measurements with a parallel method

The homogeneous nucleation rate for sickle hemoglobin polymerization has been measured for concentrations from 3.9 to 4.9 mM and temperatures from 13 degrees C to 35 degrees C by observing the stochastic fluctuations of the time to complete 10% of the reaction after photolysis of the carboxy derivative. To allow efficient data collection, a mesh was used to divide the photolysis beam into an array of smaller beams, which allowed parallel observation of about 100 different regions. Nucleation rates measured here are consistent with more restricted previously published data and, when combined with directly measured monomer addition rates, are consistent with previous analysis of progress curves. By describing these rates with equilibrium nucleation theory, the concentration of nuclei and hence their stability can be ascertained. Consequently, the chemical potential by which a monomer is attached to the polymer is determined. This attachment energy ranges from -6.6 to -8.0 kcal/mol between 15 degrees C and 35 degrees C. The enthalpic part of that chemical potential is found to be equal to the enthalpy determined by solubility measurements, as expected from thermodynamic considerations. The entropic portion of the contact chemical potential contributes from -21.4 to -8.7 kcal/mol. The vibrational chemical potential of monomers in the polymer ranges from -25.7 to -27.4 kcal/mol over the same temperatures.

Comparison of continuous step-and-shoot versus step-and-shoot acquisition SPECT

This study compared the quality of SPECT images obtained with step-and-shoot mode (SSM) and continuous step-and-shoot mode (CSSM).

METHODS

Computer simulations of SSM and CSSM were performed with a two-dimensional Shepp-Logan head phantom and a high-resolution parallel-hole collimator. The effects of noise and photon attenuation were examined.

RESULTS

Without noise and without attenuation, small structures in reconstructed images obtained using fast CSSM (less than 4 sec per view plus the moving time from one view to the next) were slightly blurred and rotated in the opposite direction of detector motion. With both noise and attenuation, these artifacts were not visible, and the image quality obtained from CSSM, especially from fast CSSM, was improved as compared to that resulting from the corresponding SSM due to the increasing number of counts. The improvement of image quality became less significant with increasing acquisition time and in the presence of attenuation.

CONCLUSION

For fast SPECT, CSSM provided better image quality than the corresponding SSM, especially when attenuation effects were not present. For relatively long time SPECT without attenuation compensation that is typical for clinical studies, the image quality of CSSM was similar to that of SSM.

Phantom evaluation of simultaneous thallium-201/technetium-99m aquisition in single-photon emission tomography

This study investigated downscatter effects in cardiac single-photon emission tomographic studies with simultaneous thallium-201/technetium-99m acquisition, and evaluated a previously proposed subtraction technique for downscatter compensation. Ten studies were carried out with different defect sizes and locations and varying activity distributions using four energy windows: 70+/-10% keV, 140+/-10% keV, 100+/-10% KeV, and 103+/-16% keV. The subtraction technique used the 100- or 103-keV data to remove scattered 99mTc counts from the 70-keV data. The size and contrast of infarcts in the dual-isotope 70-keV image were artificially decreased compared to those in the 140-keV image, caused by scattered 99mTc counts that were comparable to the primary 201Tl counts in the 70-keV window. The subtraction technique produced larger defects and more heterogeneous activity in the myocardial wall in dual-isotope 70-keV images compared to the corresponding 201Tl-only images. These artifacts were caused by the markedly different spatial distributions of scattered 99mTc counts in the 100-keV (or 103-keV) window as compared with the 70-keV window. It is concluded that scattered 99mTc photons may cause overestimation of ischemia and myocardial viability in simultaneous dual-isotope patient studies. The proposed subtraction technique was inaccurate and produced image artifacts. Adequate downscatter compensation methods must be developed before applying simultaneous 201Tl/99mTc acquisition in clinical practice.

The role of betagamma and alphagamma complexes in the assembly of human fibrinogen

The role of alphagamma and betagamma dimers as intermediates in the assembly of fibrinogen was examined in cell fusion experiments using stably transfected baby hamster kidney cell lines expressing one or combinations of fibrinogen chains. Fibrinogen was readily formed and secreted into the culture media when cells co-expressing beta and gamma chains and generating betagamma complexes were fused with cells expressing only the alpha chain. Likewise, when cells co-expressing alpha and gamma chains and generating alphagamma complexes were fused with cells expressing only the beta chain, fibrinogen was also formed and secreted. The relative amounts of alphagamma or betagamma intermediates observed during fibrinogen biosynthesis were determined by the levels of the component chains; i.e. when the beta chain was limiting, the alphagamma dimer was the predominant intermediate; likewise, when the alpha chain was limiting, the betagamma complex was the predominant intermediate. The incorporation of preformed alphagamma and betagamma complexes into secreted fibrinogen did not require concurrent protein synthesis, as shown by experiments employing cycloheximide. These data strongly support the role of alphagamma and betagamma complexes as functional intermediates in the assembly of fibrinogen.

TRAF6 is a signal transducer for interleukin-1

Many cytokines signal through different cell-surface receptors to activate the transcription factor NF-kappaB. Members of the TRAF protein family have been implicated in the activation of NF-kappaB by the tumour-necrosis factor (TNF)-receptor superfamily. Here we report the identification of a new TRAF family member, designated TRAF6. When overexpressed in human 293 cells, TRAF6 activates NF-kappaB. A dominant-negative mutant of TRAF6 inhibits NF-kappaB activation signalled by interleukin-1 (IL-1) but not by TNF. IL-1 treatment of 293 cells induces the association of TRAF6 with IRAK, a serine/threonine kinase that is rapidly recruited to the IL-1 receptor after IL-1 induction. These findings indicate that TRAF proteins may function as signal transducers for distinct receptor families and that TRAF6 participates in IL-1 signalling.

Optimal number of views in 360 degrees SPECT imaging

This study examined SPECT-reconstructed image quality as a function of the number of views, and determined the minimum number of views necessary to remove aliasing artifacts in 360 degrees SPECT.

METHODS

Computer simulation was performed using a two-dimensional Shepp-Logan head phantom and a high-resolution parallel-beam collimator with and without photon attenuation.

RESULTS

In 360 degrees SPECT, aliasing artifacts were reduced by changing the number of views from an even number 16 to its neighboring odd numbers 15 or 17, from 32 to 31 or 33 and from 64 to 63 or 65. Image quality of 15 or 17 views, 31 or 33 views and 63 or 65 views was similar to that of 32, 64 and 128 views, respectively.

CONCLUSION

Replacing an even number of views by its neighboring odd numbers in 360 degrees SPECT significantly decreased aliasing artifacts. Thirty-one or 33 views are sufficient to remove most of the aliasing artifacts in 360 degrees SPECT with a matrix of 64 x 64 pixels. This method can be applied to fast 360 degrees SPECT since fewer views are used.

A one-hand operation gun for transrectal prostate biopsy

OBJECTIVE

To develop a new automatic biopsy device (ABD) that enables a radiologist to obtain multiple samples with one hand and free the other hand to handle the ultrasonic scanner for continuous monitoring.

MATERIALS AND METHODS

The new ABD developed by us in April 1994 enabled a radiologist to complete all the biopsy procedures including loading and reloading the spring system, firing the device, emptying the specimen, selecting the depth of needle advancement, and multiple sampling, simply by pressing 3 buttons in turn with his/her right thumb. Using this new ABD, transrectal prostate biopsy under the guidance of transrectal ultrasonic imaging was performed in 60 consecutive cases of prostate diseases. Each biopsy procedure was completed by a single radiologist, who was able to obtain multiple specimens with one biopsy needle, using only one hand and freeing the other hand for the manipulation of the ultrasonic scanner for guidance.

RESULTS

A total of 265 satisfactory core tissue specimens of 285 needle passes (93%) were obtained from the 60 patients. Definite pathologic diagnoses were made for all the 60 patients (100%). No serious biopsy-related complications were observed. The main complications were hematuria in 24 of 60 (40%) patients and fever in 5 (8.3%).

CONCLUSION

On the basis of our experience with the 60 patients, this new ABD can be operated smoothly and effectively with the right hand, while the left hand is freed to handle the ultrasonic transducer for continuous monitoring.

Vascular hypertrophy and albumin permeability in a rat model combining hypertension and diabetes mellitus. Effects of calcium antagonism, angiotensin converting enzyme inhibition, and angiotensin II-AT1-receptor blockade

The aim of this study was to compare the effects of angiotensin converting enzyme (ACE) inhibition, angiotensin II (AII) AT1-receptor blockade, and dihydropyridine calcium antagonism on hypertrophy and on vascular albumin permeability in kidney, heart, and mesenteric artery in a model combining genetic hypertension and diabetes mellitus. Diabetes mellitus was induced by streptozotocin in 8-week-old spontaneously hypertensive rats. The animals were randomized to receive no treatment, the angiotensin converting enzyme inhibitor ramipril, the AII AT1-receptor blocker valsartan, or the dihydropyridine calcium antagonist lacidipine for 3 weeks. Vascular albumin permeability was measured as the tissue content of intravenously injected Evans blue dye (EB) in kidney, heart, and mesenteric artery and the tissue/plasma EB ratio was calculated. Systolic blood pressure was reduced by all three antihypertensive regimens. Glycemic control was similar in all diabetic groups. Kidney hypertrophy was not affected by any of the antihypertensive drugs. Hypertrophy of the mesenteric artery was enhanced by lacidipine but was not affected by ramipril or valsartan. Relative heart weight was also increased by lacidipine. Vascular albumin permeability, expressed as EB content in micrograms/gram dry weight or as tissue/plasma EB ratio, was higher in the kidneys of lacidipine-treated rats than in any other group of diabetic rats. There was a positive correlation between kidney weight/body weight and kidney/plasma EB ratio in the diabetic rats. These findings indicate that the dihydropyridine calcium antagonist lacidipine is associated with an unfavorable effect on vascular hypertrophy and on vascular albumin permeability in the kidneys in rats with hypertension and diabetes mellitus. Furthermore, there seems to be a coupling in the diabetic kidney between hypertrophy and increased vascular albumin permeability.

[The value of CA125 and LDH assays in assisting diagnosis of epithelial ovarian carcinoma]

40 first-treated cases of epithelial ovarian cancer, 13 cases of cervical cancer, 13 cases of corpus cancer and 50 cases of benign tumor were included in this study from Jan. 1991 through May 1992 to evaluate the significance of the blood CA125, LDH, CR and SA levels in assisting diagnosis of epithelical ovarian cancer. The CA125 levels of the 40 canses of ovarian cancer were higher than those of cervical cancer and corpus cancer (P < 0.05); the SS, PLR and AC of CA125 in ovarian cancer were higher than those of LDH, SA and CR (P < 0.05); the SS of CA125 in ovarian cancer was higher than that of LDH isoenzyme (P < 0.05). The results show that CA125 may be the best tumor marker in assisting ovarian cancer; CA125 is more informative than LDH, CR and SA; when CA125 is used incombination with other tumor markers, SS, SP, NPV and PPV can be greatly raised.

[Persistent and recurrent gynecologic malignant tumor treated within one year: analysis of 1,753 cases from 61 hospitals in China]

OBJECTIVE

To analyze the causes of persistent and recurrent gynecologic malignant tumors treated within 1 year.

METHODS

20,974 cases of gynecologic malignant tumors from 61 hospitals in 24 provinces admitted between 1983-1993 were collected. Out of the total, 1753 cases treated within 1 year with tumor persistence, recurrence or death were retrospectively analysed.

RESULTS

The ovarian carcinoma and vaginal cancer had the highest rates of tumor persistence, recurrence or death. Among the 1587 cases of tumor persistence or recurrence, pathological grading were not performed in 56.52% of the cases. For surgical treatment, inappropriate operation were done in 81.68% (767/939) of the ovarian carcinoma, 64.38% (103/160) of the cervical carcinoma, and 70.08% (89/127) of the endometrial cancer. 55.47% (532/959) of ovarian cancer and 38.31% (59/154) of choriocarcinoma and malignant mole had insufficient chemotherapy. For cervical cancer, 54.90% (235/396) of the cases did not receive enough doses of radiotherapy.

CONCLUSION

Accurate staging and standardized therapy are important for improving 1 year survival rate in malignant gynecologic tumors.

The beta 1 sodium channel subunit modifies the interactions of neurotoxins and local anesthetics with the rat brain IIA alpha sodium channel in isolated membranes but not in intact cells

Mammalian brain sodium channels consist of an alpha subunit and two smaller beta subunits. The role of the beta 1 subunit in modulating ligand interactions at these channels was examined using a cell line stably expressing human beta1 and rat brain IIA alpha subunits. Coexpression of the beta 1 subunit had no effect on the potencies of sodium channel blockers in inhibiting whole cell [3H]batrachotoxinin A benzoate ([3H]BTX) binding or veratridine-stimulated [14C]guanidinium influx. Coexpression of the beta 1 subunit also had no effect on the potencies of alpha scorpion toxin, brevetoxin, or RU 39568 in stimulating [14C]guanidinium influx. By contrast, coexpression of the beta 1 subunit had dramatic effects on ligand interactions in isolated membranes. In isolated membranes of cells expressing only the alpha subunit, the neurotoxins had no stimulatory effect on [3H]BTX binding and the potencies of local anesthetic-like channel inhibitors were 10-100-fold lower than those at native sodium channels. Whereas in membranes of cells coexpressing the beta 1 subunit, the neurotoxins increased [3H]BTX binding 30-fold and the potencies of the sodium channel inhibitors closely matched those found at native sodium channels. These findings indicate that the beta 1 subunit is not required for the binding of sodium channel activators or inhibitors but rather, that the beta 1 subunit may stabilize the alpha subunit in a functional conformation thereby allowing detection of these interactions in disrupted membranes.

A perfume odour-sensing system using an array of piezoelectric crystal sensors with plasticized PVC coatings

Using PVC polymer as membrane matrix and di-n-octylphenyl phosphate (DOPP) as plasticizer, a piezoelectric crystal sensor (PCS) array with 12 adsorptive materials selected from 68 compounds by cluster analysis has been constructed as a perfume odour-sensing system. The frequency shift data obtained from the sensor array responding to four commercial perfume odours are first autoscaled and then treated by principal component analysis. The experimental results show that the plasticized PVC membrane PCS array provides improved performance of pattern recognition compared with the single adsorptive coating PCS array. The frequency shift response characteristics of these sensors have been investigated experimentally. The proposed sensor array has also been applied to the classification of commercial spirituous liquor, wine and soft drink samples, as well as aliphatic alcohol homologues and isomers.

[A study of intraarticular irrigation-injection therapy of temporomandibular joint and its mechanism]

According to the research that there were some immune and inflammatory substances in the synovial fluid of temporomandibular joint disturbance syndrome (TMJDS), we improved the traditional intraarticular injection and developed an intraarticular irrigation-injection therapy to treat 43 cases of TMJDS and got a good result. The controls include two groups, the simple rinsing and the traditional injection. Statistical analysis showed a highly significant difference in the effects between test and control groups. In order to study the mechanism of the therapy, the tumor necrosis factor (TNF) in synovial fluid of 8 cases were assessed. It was found that the concentration of TNF was reduced markedly after treatment. We think that the new therapy is effectable for TMJDS and could be used widely.

[Monoclonal antibodies to human progesterone receptors: production, indentification and clinical application]

A peptide with 15 amino acid of human progesterone receptor (PR) was synthesized and used as antigen. Five hybridoma cells were obtained by cloning technique. In tests to hybridoma cell H4, the site specificity of the antibody to PR was found. The antibody reacted specifically with PR, but did not cross-react with ER, AR, or GR. Five women who used clomiphene citrate (CC) 100mg/d x 5 days were involved in a study of serum pregesterone (P) and endometrial histology in early luteal phase. There was no difference in serum P level in two groups. Three cases in CC group showed abnormal secretory endometrium. PR concentration in the nuclei of glandular cells of endometrium in CC group was significantly lower than that in the control group. In women with abnormal secretory endometrium, PR concentration in the nuclei of glandular cells was lower than that in women with normal endometrial histology. CC can influence endometrial histology by changing-PR concentration in the nuclei of glandular cells. The endometrium can not respond to the stimulus of P at normal levels and thus results in luteal phase defect.

IRAK: a kinase associated with the interleukin-1 receptor

The pleiotropic biological activities of interleukin-1 (IL-1) are mediated by its type I receptor (IL-1RI). When the ligand binds, IL-1RI initiates a signaling cascade that results in the activation of the transcription regulator nuclear factor kappa B (NF-kappa B). A protein kinase designated IRAK (IL-1 receptor-associated kinase) was purified, and its complementary DNA was molecularly cloned. When human embryonic kidney cells (cell line 293) over-expressing IL-1RI or HeLa cells were exposed to IL-1, IRAK rapidly associated with the IL-1RI complex and was phosphorylated. The primary amino acid sequence of IRAK shares similarity with that of Pelle, a protein kinase that is essential for the activation of a NF-kappa B homolog in Drosophila.

A 50th order reaction predicted and observed for sickle hemoglobin nucleation

Sickle hemoglobin polymerization exhibits a striking sensitivity to initial concentration, with characteristic reaction times that exhibit 30th power dependence on concentration. This extraordinary reaction order is encompassed by a novel double nucleation mechanism that predicts 50th power dependence of the homogeneous nucleation rate. Using a technique that allows individual homogeneous nucleation events to be monitored, we have measured a concentration dependence of 47+/-, in excellent agreement with the predictions of the model. Absolute nucleation rates agree with predictions as well.

NF-kappa B-mediated chromatin reconfiguration and transcriptional activation of the HIV-1 enhancer in vitro

NF-kappa B is a potent inducible transcription factor that regulates many genes in activated T cells. In this report we examined the ability of different subunits of NF-kappa B to enhance HIV-1 transcription in vitro with chromatin templates. We find that the p65 subunit of NF-kappa B is a strong transcriptional activator of nucleosome-assembled HIV-1 DNA, whereas p50 does not activate transcription, and that p65 activates transcription synergistically with Sp1 and distal HIV-1 enhancer-binding factors (LEF-1, Ets-1, and TFE-3). These effects were observed with chromatin, but not with nonchromatin templates. Furthermore, binding of either p50 or p65 with Sp1 induces rearrangement of the chromatin to a structure that resembles the one reported previously for integrated HIV-1 proviral DNA in vivo. These results suggest that p50 and Sp1 contribute to the establishment of the nucleosomal arrangement of the uninduced provirus in resting T cells, and that p65 activates transcription by recruitment of the RNA polymerase II transcriptional machinery to the chromatin-repressed basal promoter.

Characterization of the 5'-flanking region of the gene for the gamma chain of human fibrinogen

The 5'-flanking region of the gene coding for the gamma chain of human fibrinogen was characterized for its promoter activity. Reporter gene studies using chloramphenicol acetyltransferase as the indicator along with mutations in the DNA showed that a TATA-like sequence (-20 to -23 base pairs (bp)), a CAAT-like sequence (-54 to -57 bp), and an upstream stimulatory factor (USF) binding site (-66 to -77 bp) constitute a minimal promoter that mediates liver-specific expression of the gene. Electrophoretic gel mobility assays and antibody binding studies confirmed the interaction of USF with the binding site. An IL-6 responsive element with a sequence of CTGGAA located at -301 to -306 bp was shown to be a functional element in the IL-6 response. In contrast to the IL-6 responsive elements in the human alpha- and beta-fibrinogen genes, the element in the gene for the gamma chain of human fibrinogen was unaffected by the presence or elevated levels of the beta or delta isoforms of the CCAAT/enhancer binding proteins. A negative element with sequence homology to several silencer elements was also identified in the region of -348 to -390 bp of the gene for the gamma chain of human fibrinogen. A comparison of the regulatory elements in the genes coding for all three chains in fibrinogen is also presented.

GABAB receptor-mediated effects in synaptosomes of lethargic (lh/lh) mice

Previously, we have shown a significant increase in number of GABAB receptor binding sites in neocortex and thalamus of lethargic (lh/lh) mice, a mutant strain exhibiting absence seizures. This study was performed to test our hypothesis that presynaptic GABAB receptors would inhibit [3H]GABA release to a greater degree in lh/lh mice compared with their nonepileptic littermates (designated +/+). Synaptosomes isolated from neocortex and thalamus of age-matched male lh/lh and +/+ mice were similar in uptake of [3H]GABA. In the neocortical preparation, baclofen dose-dependently inhibited [3H]GABA release evoked by 12 mM KCl, an effect mediated by GABAB receptors. The maximal inhibition (Imax) value was significantly greater (80%) in lh/lh than +/+ mice, whereas the IC50 (3 microM) was unchanged. In the thalamic preparation, the effect of baclofen (50 microM) was 58% less robust in lh/lh mice. Other effects mediated by GABAB receptors (inhibitions in Ca2+ uptake and cyclic AMP formation) were also significantly reduced in thalamic synaptosomes from lh/lh mice. These data suggest a greater presynaptic GABAB receptor-mediated effect in neocortex and a reduced effect in thalamic nuclei of lh/lh mice. It is possible that selective effects of presynaptic GABAB receptors or GABA release in neocortex and thalamic nuclei of lh/lh mice may contribute to mechanisms underlying absence seizures.

Pentoxifylline ameliorates pulmonary damage caused by Streptococcus pneumoniae infection in mouse

Streptococcus pneumoniae stimulated mouse peritoneal macrophage to release tumor necrosis factor-alpha (TNF alpha) in vitro. When penicillin was added into the medium with bacteria, TNF alpha release was accelerated. Pentoxifylline (PTX), a phosphodiesterase inhibitor, significantly attenuated TNF alpha release caused either by Streptococcus pneumoniae or by its lysates. In this experiment, 150 Kunming mice were infected with Streptococcus pneumoniae through inspiration. Dynamic changes of TNF alpha concentration in serum and bronchoalveolar lavage fluid were determined, and pulmonary pathological changes were also observed. It was found that PTX significantly attenuated TNF alpha activity in serum and bronchoalveolar lavage fluid, and inhibited white blood cell chemotaxis, emigration and infiltration. In conclusion, Streptococcus pneumoniae infection stimulates the release of TNF alpha which is probably the major mediater that causes tissue damage during Streptococcus pneumoniae infection. The mechanism is probably that Streptococcus pneumoniae and its lysates activate TNF alpha gene transcription. As penicillin accelerates TNF alpha release, treatment with penicillin alone may aggravate the tissue damage. Combined treatment with PTX may be more reasonable.

Neural network of structures in which GABAB receptors regulate absence seizures in the lethargic (lh/lh) mouse model

In previous work we have shown that GABAB receptors are required for expression of absence seizures in the lethargic (lh/lh) mouse model; that lh/lh mice have increased numbers of GABAB binding sites compared to nonepileptic littermates (designated +/+); and that the magnitude of the increased number of GABAB receptors in lh/lh mice correlated positively with the frequency of absence seizures. We performed this study to delineate the neural network in which GABAB receptors regulate absence seizures in lh/lh mice. We designed three successive screens which had to be passed by a candidate neuronal population before it could be considered a member of the neural network in which GABAB receptors regulate absence seizures. First, the neuronal populations in lh/lh mice had to have enriched GABAB binding sites compared to homologous populations in matched nonepileptic controls; baclofen-displaceable 3H-GABA binding was measured in autoradiograms for this screen. Second, the candidate populations had to generate spike-wave discharges (SWDs) during absence seizures in lh/lh mice; bipolar recording electrodes implanted into candidate neuronal structures were used in this screen. Third, the candidate populations had to demonstrate GABAB receptor-mediated regulation of absence seizures in lh/lh mice; microinjections of a GABAB agonist [(-)-baclofen] and antagonist (CGP 35348) were used for this screen. In this study we found that anterior ventral lateral thalamic nucleus (VLa), nucleus reticularis thalami (NRT), nucleus reuniens (RE) passed all three screens, and hence are members of the neural network in which GABAB receptors regulate absence seizures in lh/lh mice.

Detection of human papillomavirus types 16, 18 DNA related sequences in bronchogenic carcinoma by polymerase chain reaction

In studying the relationship between human papillomavirus (HPV) and bronchogenic carcinoma, "high-risk" HPV 16, 18 DNA sequences were detected in samples from 50 lung cancer patients, 18 patients with benign pulmonary diseases and 4 fetal lung tissues by polymerase chain reaction (PCR) and dot-blot hybridization with biotin-labelled probes. The results showed that HPV 16, 18 DNA related sequences were found in 32% of lung cancer specimens, with 10 cases of HPV 16, 5 cases of HPV 18 and 1 case of both types. 48.15% (13/27) of squamous cell carcinomas were shown to be positive for HPV 16, 18 DNA. In addition, two adenocarcinomas and one small cell carcinoma were positive for HPV 16 DNA. No specimens from benign diseases tissues and fetal lung tissues showed positive results. These results suggest that primary bronchogenic carcinoma is related to HPV infection.

NF-kappa B activation by interleukin-1 (IL-1) requires an IL-1 receptor-associated protein kinase activity

An important function of interleukin-1 (IL-1) is activation of the transcription factor NF-kappa B, which is signaled via the type I IL-1 receptor (IL-1RI). By receptor mutagenesis studies, we have identified a region of the cytoplasmic domain of IL-1RI that is required for both IL-1-mediated NF-kappa B activation and IL-1-dependent activation of a receptor-associated protein kinase activity we term IRAK. No IL-1RI mutants were found that can activate NF-kappa B in the absence of IRAK activity. Therefore, we propose that IRAK activation is a necessary step in the activation of NF-kappa B by IL-1.

Differences in the anatomic distribution of immediate-early gene expression in amygdala and angular bundle kindling development

Kindling is a model in which fleeting changes of neuronal activity produce a lifelong modification of neuronal structure and function in the mature nervous system. Immediate-early genes (IEGs) such as c-fos have been implicated as a causal link in the chain of molecular events coupling fleeting pathologic activity to lasting hyperexcitability. Identification of the brain structures exhibiting IEG expression during the evolution of kindling is necessary to guide investigations of the phenotypic consequences. We used in situ hybridization histochemistry to identify the structures exhibiting expression of multiple IEGs during the evolution of amygdala kindling and compared this to the pattern following angular bundle kindling. The principal findings included that: (1) generalized limbic and clonic motor (class 5) kindled seizures evoked by stimulation of one amygdala induced the expression of IEGs in a small subset of limbic structures with remarkable symmetry between the two hemispheres; (2) the anatomic extent of seizure-evoked expression of c-fos mRNA expanded progressively following focal limbic and motor (classes 0-3) seizures during the development of amygdala kindling; c-fos mRNA was detected first ipsilaterally in AM, ACO, and PC and with higher-class seizures in hippocampal formation and homologous structures contralaterally, and (3) class 5 seizures evoked by stimulation of two different sites in the limbic system (amygdala or angular bundle) induced IEG expression in distinct but partially overlapping anatomic structures. We propose that synaptic activation of glutamate receptors contributes to the expression of these diverse IEGs throughout the forebrain. The findings provide a constellation of anatomic structures in which to investigate the structural and functional consequences of IEG expression.

[Chemotherapy against lymphatic metastases of gynecologic cancer via pelvic retroperitoneal cannulation: a preliminary report]

Lymphatic metastasis is one of the most important problems in the treatment of gynecologic malignancy. We conducted a preliminary investigation on the feasibility and practicality of chemotherapy against lymphatic metastases of gynecologic cancer via pelvic retroperitoneal cannulation. 5-FU mixed with Isovist-300 was injected into the pelvic retroperitoneal space. X-ray films revealed that the external iliac, hypogastric, obturator, deep inguinal and most of the common iliac lymph nodes were submerged in the 5-FU solution. 5-FU concentrations in the lymph nodes were measured by high pressure liquid chromatography, which showed that 5-FU concentration of the study group was 2 to 10 times that of the control group. Pathologic findings revealed that most of the metastatic cancer cells in the study group showed obvious degeneration and necrosis while no changes were observed in the control group. No major complications or adverse effects were observed. Our results suggest that this method may be used to treat the lymphatic metastases of gynecologic cancer.

Cascade regulation of terminal adipocyte differentiation by three members of the C/EBP family of leucine zipper proteins

Terminal differentiation of cultured 3T3-L1 fibroblasts to the adipogenic phenotype is potently stimulated by dexamethasone (DEX) and methylisobutylxanthine (MIX). Previous studies have shown that these hormones induce the expression of genes encoding two members of the CCAAT/enhancer binding protein (C/EBP) family of transcription factors. In the absence of new protein synthesis DEX activates the gene encoding C/EBP delta. Likewise, MIX is a direct inducer of C/EBP beta gene expression. Optimal conditions for differentiation entail a 2-day period wherein confluent fibroblasts are exposed to DEX and MIX, followed by removal of the hormones and subsequent culture in the presence of insulin and fetal bovine serum. During the early phase of differentiation, high levels of C/EBP delta and C/EBP beta accumulate. These transcription factors diminish during the terminal phase of differentiation and come to be replaced by a third member of the C/EBP family, C/EBP alpha. Conclusive evidence has already shown that C/EBP alpha regulates terminal adipocyte differentiation, turning on the battery of fat-specific genes required for the synthesis, uptake, and storage of long chain fatty acids. Here we provide evidence that C/EBP delta and C/EBP beta play early catalytic roles in the differentiation pathway, relaying the effects of the hormonal stimulants DEX and MIX in a cascade-like fashion, leading to the activation of the gene encoding C/EBP alpha. Conditions facilitating the precocious expression of either C/EBP delta or C/EBP beta were observed to accelerate adipogenesis and, in the case of C/EBP beta, relieve dependence on the early hormonal stimulants. Likewise, conditions that prevented the expression of functional C/EBP beta effectively blocked terminal differentiation. Finally, we have discovered that ectopic expression of C/EBP beta in multipotential NIH-3T3 cells results in their conversion into committed adipoblasts capable, upon hormonal stimulation, of synchronous and uniform differentiation into fat-laden adipocytes.

Regulatory elements and transcription factors controlling basal and cytokine-induced expression of the gene encoding intercellular adhesion molecule 1

The gene encoding intercellular adhesion molecule 1 (ICAM-1) is transcriptionally induced in response to inflammatory and immunomodulatory cytokines. To investigate the mechanisms controlling ICAM-1 gene expression, we have identified regulatory DNA sequences responsible for maintaining basal and mediating induced transcription in response to tumor necrosis factor alpha (TNF-alpha) and interferon gamma (IFN-gamma). Regulatory elements centered 115, 60, and 40 bp upstream from the ICAM-1 transcription start site were implicated in cytokine-independent gene expression. Regulatory elements dedicated to TNF-alpha and IFN-gamma were identified 190 and 90 bp, respectively, upstream from the ICAM-1 transcription start site. A combination of mutagenesis and DNA-binding assays revealed that the TNF-alpha response element is composite, consisting of binding sites for both C/EBP and NF-kappa B. The IFN-gamma response element behaved as a simple regulatory element that selectively binds to an IFN-gamma-inducible activity composed, at least in part, of p91. These observations provide a framework for understanding how extracellular signals dynamically regulate the adhesive properties of mammalian cells.

A filtering technique to compensate for detector response in converging-beam SPECT reconstruction

In this study a non-stationary filtering technique was developed to compensate for spatially variant detector response in fan- and cone-beam SPECT. First the frequency-distance relation for fan- and cone-beam geometries was derived from their parallel-beam counterpart, and then used to compute the Fourier transform of the detector response that was used as the MTF of a Metz filter. The filter was applied to the blurred data before reconstruction. The unique feature of the derived MTF is that it depends on source location, so the filtering is spatially variant. Results of evaluation studies demonstrate that the ratio between the tangential and radial FWHMS of the reconstructed point response function obtained from our filtering technique is closer to one and varies less with source location as compared to the ratio obtained without compensation or using Metz filtering with a stationary detector response. This improvement is mainly because the tangential FWHM is increased to match the radial FWHM better. With a higher order of Metz filter, both tangential and radial FWHMS are slightly smaller but their ratio deviates more from one compared to those of lower orders. In conclusion, our filtering technique provides an effective means to compensate for detector response mainly in terms of reducing anisotropy of the point response function.

[An preliminary study on hepato-protective action of seed oil of Hippophae rhamnoides L. (HR) and mechanism of the action]

The seed oil of Hippophae rhamnoides markedly inhibits the rise of MDA in liver of mice and rats induced by CCl4, AAP and ethyl alcohol, decreases significantly the activity of SGPT and SGOT, and markedly checks the depletion of GSH in liver of mice induced by AAP. The microscopic and electron-microscopic examination has shown that the seed oil can lighten liver injury.

A second mutation associated with apparent beta-hexosaminidase A pseudodeficiency: identification and frequency estimation

Deficient activity of beta-hexosaminidase A (Hex A), resulting from mutations in the HEXA gene, typically causes Tay-Sachs disease. However, healthy individuals lacking Hex A activity against synthetic substrates (i.e., individuals who are pseudodeficient) have been described. Recently, an apparently benign C739-to-T (Arg247Trp) mutation was found among individuals with Hex A levels indistinguishable from those of carriers of Tay-Sachs disease. This allele, when in compound heterozygosity with a second "disease-causing" allele, results in Hex A pseudodeficiency. We examined the HEXA gene of a healthy 42-year-old who was Hex A deficient but did not have the C739-to-T mutation. The HEXA exons were PCR amplified, and the products were analyzed for mutations by using restriction-enzyme digestion or single-strand gel electrophoresis. A G805-to-A (Gly269Ser) mutation associated with adult-onset GM2 gangliosidosis was found on one chromosome. A new mutation, C745-to-T (Arg249Trp), was identified on the second chromosome. This mutation was detected in an additional 4/63 (6%) non-Jewish and 0/218 Ashkenazi Jewish enzyme-defined carriers. Although the Arg249Trp change may result in a late-onset form of GM2 gangliosidosis, any phenotype must be very mild. This new mutation and the benign C739-to-T mutation together account for approximately 38% of non-Jewish enzyme-defined carriers. Because carriers of the C739-to-T and C745-to-T mutations cannot be differentiated from carriers of disease-causing alleles by using the classical biochemical screening approaches, DNA-based analyses for these mutations should be offered for non-Jewish enzyme-defined heterozygotes, before definitive counseling is provided.

[Study on estrogen and progesterone receptors in endometriosis and adenomyosis]

Estrogen and progesterone receptors (ER and PR) in 18 cases of ovarian endometriosis and 13 cases of adenomyosis were determined with dextran coated charcoal (DCC) method. The levels of ER and PR in those specimens were lower than those of normal endometrium. Among the 18 cases of ovarian endometriosis, 6 (33.4%) were negative for PR, which accounted for the unsatisfactory results of progesterone treatment for some endometriosis. In the 13 cases of adenomyosis there were 10 (76.9%) showing positive PR. It is suggested that the hormone therapy may be useful to treat those young patients with adenomyosis instead of surgery. The correlation of the ER and PR levels, the treatment and prognosis in endometriosis and adenomyosis are worth further studying.