Multi-layer imaging of human organs by measurement of laser backscattered radiation

Laser backscattered radiations from tissue phantoms and human forearms are measured by a reflectance imager. Laser radiations are guided by an optical fibre, and the backscattered radiations are collected by three optical fibres in the measurement probe assembly, placed at distances of 2 mm, 4 mm and 6 mm from the input fibre. By placing the measurement probe on the phantom or tissue surface and matching the outline on the computer monitor, the reflectance data from the organ or the phantom are collected. These data, after digitisation, interpolation and filtering, are colour coded and displayed on the computer monitor. Using this imaging procedure, the abnormalities embedded at different depths in the phantoms are located. The structural changes due to colour, composition and blood flow in the multi-layer of human forearms of various subjects are qualitatively shown in reflectance images obtained by this procedure.

Mutational pattern of the nurse shark antigen receptor gene (NAR) is similar to that of mammalian Ig genes and to spontaneous mutations in evolution: the translesion synthesis model of somatic hypermutation

The pattern of somatic mutations of shark and frog Ig is distinct from somatic hypermutation of Ig in mammals in that there is a bias to mutate GC base pairs and a low frequency of mutations. Previous analysis of the new antigen receptor gene in nurse sharks (NAR), however, revealed no bias to mutate GC base pairs and the frequency of mutation was comparable to that of mammalian IgG. Here, we analyzed 1023 mutations in NAR and found no targeting of the mechanism to any particular nucleotide but did obtain strong evidence for a transition bias and for strand polarity. As seen for all species studied to date, the serine codon AGC/T in NAR was a mutational hotspot. The NAR mutational pattern is most similar to that of mammalian IgG and furthermore both are strikingly akin to mutations acquired during the neutral evolution of nuclear pseudogenes, suggesting that a similar mechanism is at work for both processes. In yeast, most spontaneous mutations are introduced by the translesion synthesis DNA polymerase zeta (REV3) and in various DNA repair-deficient backgrounds transitions were more often REV3-dependent than were transversions. Therefore, we propose a model of somatic hypermutation where DNA polymerase zeta is recruited to the Ig locus. An excess of DNA glycosylases in germinal center reactions may further enhance the mutation frequency by a REV3-dependent mutagenic process known as imbalanced base excision repair.

Stealth monensin liposomes as a potentiator of adriamycin in cancer treatment

Small unilamellar stealth monensin liposomes (SMLs) were prepared from multilamellar liposomes (MLVs). The MLVs were prepared by using dipalmitoyl phosphatidylcholine (DPPC), cholesterol, distearoyl glycerophosphoethanolamine coupled to poly(ethylene glycol) (DSPE-PEG) and stearylamine in the molar ratio of 10:5:1.4:1.4 (32.8 mM total lipid). The encapsulation efficiencies of monensin in MLVs and small unilamellar vesicles (SUVs) was 6x10++(-6) and 10(-7) M, respectively. The stability of SMLs was studied at 4 degrees C. The amount of leakage of monensin from SMLs was less than 20% after four weeks of storage. The in vitro release of monensin from SMLs in human serum was determined, and t1/2 was found to be 10 h. Pharmacokinetic studies on SMLs were carried out in BALB/c mice. More than 20% of SMLs remained in blood circulation after 24 h. SMLs increased the uptake of adriamycin (AM) in HL-60-resistant cells by more than two fold, compared to monensin in solution. SMLs potentiated the effect of AM against both sensitive and resistant HL-60 cells (six- and tenfold potentiation, respectively) and human LOVO tumor cells (four- and 200-fold potentiation, respectively). However, the highest potentiation was observed against resistant human breast tumor MCF7 cells, and was found to be 2400 times in comparison to AM alone. Transmission electron microscopic (TEM) studies carried out with HL-60-resistant tumor cells incubated with SMLs showed that SMLs caused dilation of the golgi of tumor cells within 10 min. The dilation of golgi was reversible after reincubation of the cells in fresh medium. SMLs showed considerable potential as a potentiator in combination with AM in overcoming drug resistance.

Possible role of cardiac mast cells in norepinephrine-induced myocardial preconditioning

The present study was designed to investigate the role of cardiac mast cells in the cardioprotective effect of norepinephrine-induced preconditioning. Isolated rat heart was subjected to 30 min of global ischemia followed by 30 min of reperfusion. Both ischemic and norepinephrine (100 microM) preconditioning markedly reduced ischemia-reperfusion-induced release of lactate dehydrogenose (LDH) in the coronary effluent and the incidence of ventricular premature beats (VPBs) and ventricular tachycardia/fibrillation (VT/VF) during the reperfusion phase. Ischemic and norepinephrine preconditioning also significantly reduced ischemia-reperfusion-induced release of mast cell peroxidase (MPO), a marker of mast cell degranulation. However, MPO release increased immediately after ischemic or norepinephrine preconditioning. Histological study with ruthenium red (0.005%) staining confirmed cardiac mast cell degranulation in ischemic and norepinephrine preconditioned isolated rat hearts. These findings tentatively suggest that pharmacological preconditioning with norepinephrine produces a cardioprotective and antiarrhythmic effect similar to ischemic preconditioning through degranulation of resident cardiac mast cells.

Role of angiotensin in cardioprotective effect of ischemic preconditioning

This study was designed to investigate the role of angiotensin (Ang II) in the cardioprotective effect of ischemic preconditioning. Isolated perfused rat heart was subjected to global ischemia for 30 min followed by reperfusion for 120 min. Coronary effluent was analyzed for lactate dehydrogenase (LDH) and creatine kinase (CK) release to assess the degree of cardiac injury. Myocardial infarct size was estimated macroscopically by using triphenyl tetrazolium chloride (TTC) staining. Four episodes of ischemic/Ang II preconditioning markedly reduced LDH and CK release in the coronary effluent and decreased myocardial infarct size. The cardioprotective effect of Ang II preconditioning was abolished by CV 11974, AT1-receptor antagonist, whereas no such effect was noted with CV 11974 in ischemic preconditioning. PD 123319, AT2-receptor antagonist, produced no marked effect on Ang II preconditioning and ischemic preconditioning induced reduction in myocardial injury. On the basis of these results, it may be concluded that activation of AT1 receptors may be involved in angiotensin-induced pharmacologic preconditioning. But it may not be involved in the cardioprotective effect of ischemic preconditioning in isolated rat heart.

Parsing silhouettes: the short-cut rule

Many researchers have proposed that, for the purpose of recognition, human vision parses shapes into component parts. Precisely how is not yet known. The minima rule for silhouettes (Hoffman & Richards, 1984) defines boundary points at which to parse but does not tell how to use these points to cut silhouettes and, therefore, does not tell what the parts are. In this paper, we propose the short-cut rule, which states that, other things being equal, human vision prefers to use the shortest possible cuts to parse silhouettes. We motivate this rule, and the well-known Petter's rule for modal completion, by the principle of transversality. We present five psychophysical experiments that test the short-cut rule, show that it successfully predicts part cuts that connect boundary points given by the minima rule, and show that it can also create new boundary points.

Oligonucleotide inhibition of the interaction of HIV-1 Tat protein with the trans-activation responsive region (TAR) of HIV RNA

The interaction of HIV-1 Tat protein with its recognition sequence, the trans-activation responsive region TAR is a potential target for drug discovery against HIV infection. We show by use of an in vitro competition filter binding interference assay that synthetic oligodeoxyribonucleotides complementary to the HIV-1 TAR RNA apical stem-loop and bulge region inhibit the binding of Tat protein or a Tat peptide (residues 37-72) better than two small molecules that have been shown to bind TAR RNA, Hoechst 33258 and neomycin B. The inhibition is not sensitive to length between 13 and 16 residues or precise positioning but shorter oligonucleotides are less effective. Enhanced inhibition was obtained for a 16-mer 2'-O-methyl oligoribonucleotide but not for C5-propyne pyrimidine-substituted oligonucleotides. Control non-antisense oligonucleotides were occasionally also effective in filter binding interference but only the complementary antisense 2'-O-methyl oligoribonucleotide was effective in gel mobility shift assays in direct TAR binding or in interference with Tat peptide binding to the TAR stem-loop. This is the first demonstration of effective inhibition of the Tat-TAR interaction by nuclease-stabilized oligonucleotide analogues.

Induction of cellular immunity to a mycobacterial antigen adsorbed on lamellar particles of lactide polymers

Microspheres prepared from synthetic, biodegradable poly (L-lactide) [PLA] and copolymers of lactide and glycolide such as poly (DL lactide co-glycolide) [PLG] have been widely investigated for controlled delivery of encapsulated vaccine antigens. In this study we describe novel lamellar microparticles produced from PLA to which protein antigens can be adsorbed. These particles when administered to mice, induced strong Th1-type T cell responses to the adsorbed 38 kDa protein antigen from M. tuberculosis characterised by high levels of Interferon-gamma. In addition to proteins, we were also able to adsorb synthetic peptides resulting in specific T cell proliferation. Induction of strong cellular immunity together with the versatility of antigen adsorption to these particles should make such lamellae a useful tool to deliver protective antigens from intracellular pathogens.

Characterization of protein profiles and cross-reactivity of Blastocystis antigens by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblot analysis

The protein profiles of Blastocystis hominis, B. lapemi, and B. ratti were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and species could be differentiated by this means as well as by Western-blot analysis with polyclonal antibodies. No intraspecies difference could be distinguished between the two B. hominis isolates or the three B. ratti isolates. Western-blot analysis showed extensive cross-reactivity of B. lapemi and B. hominis antigens with anti-B. ratti serum. Some of the cross-reactive antigens were glycoproteins as determined on the basis of their sensitivity to periodate treatment.

Immune responses to recombinant proteins of Mycobacterium leprae

Identification of antigenic determinants of the polar immune response in leprosy may illuminate both protection and pathogenesis. Thirty subjects were studied (22 with polar disease and 8 healthy controls who were heavily exposed but disease-free) by assaying the proliferative, interferon (IFN)-gamma, and antibody responses to recombinant antigens of Mycobacterium leprae (10, 28, 36, and 65 kDa). The 10-kDa antigen elicited IFN-gamma production from all tuberculoid (TT) and borderline tuberculoid (BT) patients but little from controls, lepromatous (LL), or borderline lepromatous (BL) patients (P<.05). Production of 65-kDa-specific IFN-gamma was higher in TT/BT than in controls or LL/BL patients (P<.006). All subjects produced 65-kDa-specific antibody, but it was higher in LL/BL patients than in healthy controls, whose responses were higher than in TT/BT subjects (P=.035). The 36-kDa antibody responses were selectively increased in LL/BL subjects (P<.02). The intermediate phenotype of the controls suggests that M. leprae-specific production of IFN-gamma may contribute to pathology and to protection in leprosy.

Novel mechanisms of estrogen action in the brain: new players in an old story

Estrogen elicits a selective enhancement of the growth and differentiation of axons and dendrites (neurites) in the developing brain. Widespread colocalization of estrogen and neurotrophin receptors (trk) within estrogen and neurotrophin targets, including neurons of the cerebral cortex, sensory ganglia, and PC12 cells, has been shown to result in differential and reciprocal transcriptional regulation of these receptors by their ligands. In addition, estrogen and neurotrophin receptor coexpression leads to convergence or cross-coupling of their signaling pathways, particularly at the level of the mitogen-activated protein (MAP) kinase cascade. 17beta-Estradiol elicits rapid (within 5-15 min) and sustained (at least 2 h) tyrosine phosphorylation and activation of the MAP kinases, extracellular-signal regulated kinase (ERK)1, and ERK2, which is successfully inhibited by the MAP kinase/ERK kinase 1 inhibitor PD98059, but not by the estrogen receptor (ER) antagonist ICI 182,780 and also does not appear to result from estradiol-induced activation of trk. Furthermore, the ability of estradiol to phosphorylate ERK persists even in ER-alpha knockout mice, implicating other estrogen receptors such as ER-beta in these actions of estradiol. The existence of an estrogen receptor-containing, multimeric complex consisting of hsp90, src, and B-Raf also suggests a direct link between the estrogen receptor and the MAP kinase signaling cascade. Collectively, these novel findings, coupled with our growing understanding of additional signaling substrates utilized by estrogen, provide alternative mechanisms for estrogen action in the developing brain which could explain not only some of the very rapid effects of estrogen, but also the ability of estrogen and neurotrophins to regulate the same broad array of cytoskeletal and growth-associated genes involved in neurite growth and differentiation. This review expands the usually restrictive view of estrogen action in the brain beyond the confines of sexual differentiation and reproductive neuroendocrine function. It considers the much broader question of estrogen as a neural growth factor with important influences on the development, survival, plasticity, regeneration, and aging of the mammalian brain and supports the view that the estrogen receptor is not only a ligand-induced transcriptional enhancer but also a mediator of rapid, nongenomic events.

Eustachian tube functions in atrophic rhinitis-a tympanometeric study

The present study was carried out on 60 clinically proved cases of primary atrophic rhinitis. Tympanometry was performed to evaluate the Eustachian tube functions. It was observed that in majority of cases, atrophic rhinitis does not effect the Eustachian tube functions. Only a small number of cases revealed hypofunctioning of Eustachian tube.

Cytoplasmic localization of the trypanothione peroxidase system in Crithidia fasciculata

Tryparedoxin I (TXNI) and tryparedoxin peroxidase (TXNPx), novel proteins isolated from Crithidia fasciculata, have been reported to reconstitute a trypanothione peroxidase activity in vitro (Nogoceke, E.; Gommel, D. U.; Kiess, M.; Kalisz, H. M.; Flohé, L. Biol. Chem. 378:827-836; 1997). Combined with trypanothione reductase, they may form an NADPH-fueled trypanothione-mediated defense system against hydroperoxides in the trypanosomatids. In situ confocal microscopy of antibody-stained TXNI and TXNPx and electron microscopy of the immunogold labeled proteins revealed their colocalization in the cytosol. Insignificant amounts of the enzymes were detected in the nucleus and vesicular structures, whereas the kinetoplast and the mitochondrion are virtually free of any label. Comparison of the PCR product sequences obtained with genomic and cDNA templates rules out any editing typical of kinetoplast mRNA. Sequence similarities with any of the established maxicircle genes of trypanosomatids were not detectable. It is concluded that both, TXNI as well as TXNPx are encoded by nuclear DNA and predominantly, if not exclusively localized in the cytosol. Working in concert with trypanothione reductase, they can function as an enzymatic system that reduces hydroperoxides at the expense of NADPH without any impairment of the flux of reduction equivalents by cellular compartmentation.

In vivo nickel allergic contact dermatitis: human model for topical therapeutics

Techniques to determine efficacy of topical agents on allergic contact dermatitis (ACD) may benefit from refinement. The aim of this study was to develop an in vivo human model system for the bioengineering and visual quantification of the effect of topical agents on nickel ACD, and to correlate ACD parameters. 14 nickel patch-test-positive subjects were included in a placebo-controlled, double-blind study after a pre-screening procedure with a standard diagnostic patch test with nickel sulfate in 54 healthy human volunteers. 5% nickel sulfate in petrolatum in a Finn Chamber was applied on forearm skin for 48 h to create a standardized dermatitis. Thereafter, the dermatitis was treated with a model topical agent and a placebo control while recording endpoint parameters daily for 10 days. Resolution was quantified with 4 parameters: visual scoring (VS), transepidermal water loss (TEWL) (Tewameter), skin blood flow volume (BFV) (laser Doppler flowmeter), and skin color (a* value) (Colorimeter). The model agent reduced cutaneous allergic reactions, especially on day 8 to 10, in comparison with the placebo control. A highly significant linear relationship exists among all parameters, except between a* and BFV. This model may provide robust biometrics for determining the efficacy of topical therapeutics on experimentally induced ACD.

Clinical, echocardiographic, and angiographic profile of patients with double-chambered right ventricle: experience with 48 cases

Forty-eight patients with double-chambered right ventricle (DCRV) were prospectively studied over a 3-year period. Clinical, echocardiographic, hemodynamic, and angiographic studies were done in all. Three patients were studied postoperatively also. Fifteen patients underwent surgery confirming the diagnosis. Echocardiography detected anomalous muscle bundles (AMBs) in 39/41 patients in whom this study was carried out. Angiographically AMBs were best demonstrated in anteroposterior views in a systolic frame. Common associated anomalies found with DCRV were ventricular septal defects (69%), pulmonary valve stenosis (38%), and double-outlet right ventricle (10%).

Ig heavy chain expression and class switching in vitro from an allele lacking the 3' enhancers DNase I-hypersensitive hs3A and hs1,2

The murine Ig heavy chain (IgH) 3' regulatory region contains four enhancers: hs3A, hs1,2, hs3B, and hs4. Various studies have suggested a role for these enhancers in regulating IgH expression and class switching. Here we assess the role of hs3A and hs1,2 in these processes by exploiting a naturally occurring deletion of these enhancers from the expressed, C57BL/6 allele of the F1 pre-B cell line, 70Z/3. Equivalent mu expression in 70Z/3 and 18-81 (which has an intact 3' region) indicated that hs3A and hs1,2 were not essential for mu expression at the pre-B cell stage. To further examine the role of hs3A and hs1,2 in IgH function at the plasma cell stage, we fused 70Z/3 with the plasmacytoma NSO. Electromobility shift assay analysis of the 70Z/3-NSO hybrids revealed a transcription factor complement conducive to the activation of the 3' enhancers. Despite the lack of enhancers, hs3A and hs1,2, the level of mu RNA and protein in the 70Z/3-NSO fusion hybrids was substantially elevated relative to its pre-B parent and comparable with that observed in a number of mu-producing spleen cell hybridomas. Additionally, ELISAspot assays showed that the 70Z/3-NSO hybrid underwent spontaneous class switching in culture to IgG1 at a frequency comparable with that of most hybridomas. These results indicate that hs3A and hs1,2 are not essential for high levels of IgH expression or for spontaneous class switching in a plasma cell line.

Distributed source imaging of alpha activity using a maximum entropy principle

OBJECTIVE

We present a method based on the distributed dipole source model to localize sources of spontaneous human brain activity, such as the alpha rhythm. The proposed method relies on the generalized maximum entropy principle and is implemented in frequency-domain.

METHODS

Several computer simulation studies of synchronous and asynchronous distributed dipole sources were carried out to test the validity of the method. The method was also applied to spontaneous electroencephalographic (EEG) recordings from human subjects to estimate the sources of alpha activity. The locations of these sources were registered with actual magnetic resonance images for anatomical visualization.

RESULTS

The simulation studies suggest the validity of the proposed method and its capability to detect distributed and fairly deep synchronous dipole sources. Results of human studies with 6 subjects suggest that the generators of alpha rhythm are mainly concentrated over the posterior regions of the cortex.

CONCLUSION

The proposed distributed source imaging method is a promising technique for localizing rhythmic brain activity.

Superpendentic index: a novel topological descriptor for predicting biological activity

A simple highly degenerating, pendenticity based, topological descriptor termed as superpendentic index has been conceptualized and its discriminating power investigated with regard to antiulcer activity. A data set consisting of 128 analogues of 4-substituted-2-guanidino thiazoles was selected for the present study. These analogues are reversible, competitive, and selective inhibitors of gastric H+,K(+)-ATPase enzyme. The value of superpendentic index of each analogue in the data set was computed and active range was identified. The biological activity assigned to each analogue using superpendentic index was subsequently compared with the reported in vitro and in vivo inhibitory activities. The accuracy of classification of analogues based on in vivo activity was found to be 82% in the active range using superpendentic index.

Estrogen-induced activation of mitogen-activated protein kinase in cerebral cortical explants: convergence of estrogen and neurotrophin signaling pathways

We have shown that estrogen elicits a selective enhancement of the growth and differentiation of axons and dendrites (neurites) in the developing CNS. We subsequently demonstrated widespread colocalization of estrogen and neurotrophin receptors (trk) within developing forebrain neurons and reciprocal transcriptional regulation of these receptors by their ligands. Using organotypic explants of the cerebral cortex, we tested the hypothesis that estrogen/neurotrophin receptor coexpression also may result in convergence or cross-coupling of their signaling pathways. Estradiol elicited rapid (within 5-15 min) tyrosine phosphorylation/activation of the mitogen-activated protein (MAP) kinases, ERK1 and ERK2, that persisted for at least 2 hr. This extracellular signal-regulated protein kinase (ERK) activation was inhibited successfully by the MEK1 inhibitor PD98059, but not by the estrogen receptor (ER) antagonist ICI 182,780, and did not appear to result from estradiol-induced activation of trk. Furthermore, we also found that estradiol elicited an increase in B-Raf kinase activity. The latter and subsequent downstream events leading to ERK activation may be a consequence of our documentation of a multimeric complex consisting of, at least, the ER, hsp90, and B-Raf. These novel findings provide an alternative mechanism for some of the estrogen actions in the developing CNS and could explain not only some of the very rapid effects of estrogen but also the ability of estrogen and neurotrophins to regulate the same broad array of cytoskeletal and growth-associated genes involved in neurite growth and differentiation.

Development of Blastocystis hominis cysts into vacuolar forms in vitro

The development of cysts of Blastocystis hominis isolated from human feces by the Ficoll-Paque concentration method and cultured in Jones' medium containing 10% horse serum is described. The morphological changes were studied by light and transmission electron microscopy at different intervals for up to 48 h. The cysts developed into a large number of vacuolar forms within 24 h, and binary fission was the only mode of reproduction observed.

Biological activity of the labdane diterpenes

Biological activity of diterpenes of the labdane skeleton, isolated from the terrestrial plants and marine sources during the last ten years has been reviewed.