Jaw-muscle spindle afferent pathways to the trigeminal motor nucleus in the rat

Neural pathways conveying proprioceptive feedback from the jaw muscles were studied in rats by combining retrograde and intracellular neuronal labeling. Initially, horseradish peroxidase was iontophoresed unilaterally into the trigeminal motor nucleus (Vmo). Two days later, 1-5 jaw-muscle spindle afferent axons located in the mesencephalic trigeminal nucleus were physiologically identified and intracellularly stained with biotinamide. Stained mesencephalic trigeminal jaw-muscle spindle afferent axon collaterals and boutons were predominantly distributed in the supratrigeminal region (Vsup), Vmo, dorsomedial trigeminal principal sensory nucleus (Vpdm), parvicellular reticular formation (PCRt), alpha division of the parvicellular reticular formation (PCRtA), and dorsomedial portions of the spinal trigeminal subnuclei oralis (Vodm), and interpolaris (Vidm). Numerous neurons retrogradely labeled with horseradish peroxidase from the trigeminal motor nucleus were found bilaterally in the PCRt, PCRtA, Vodm, and Vidm. Retrogradely labeled neurons were also present contralaterally in the Vsup, Vpdm, Vmo, peritrigeminal zone, and bilaterally in the dorsal medullary reticular field. Putative contacts between intracellularly stained mesencephalic trigeminal jaw-muscle spindle afferent boutons and trigeminal premotor neurons retrogradely labeled with horseradish peroxidase were found in the ipsilateral Vodm, PCRtA, and PCRt, as well as the contralateral Vsup, Vmo, Vodm, PCRt, and PCRtA. Thus, multiple disynaptic jaw-muscle spindle afferent-motoneuron circuits exist. These pathways are likely to convey long-latency jaw-muscle stretch reflexes and may contribute to stiffness regulation of the masticatory muscles.

Elucidation of neuronal circuitry: protocol(s) combining intracellular labeling, neuroanatomical tracing and immunocytochemical methodologies

We describe a protocol combining either intracellular biotinamide staining or anterograde biotinylated dextran amine (BDA) tracing with retrograde horseradish peroxidase (HRP) labeling and immunocytochemistry in order to map physiologically identified neuronal pathways. Presynaptic neurons including their boutons are labeled by either intracellular injection of biotinamide or extracellular injection of BDA while postsynaptic neurons are labeled with HRP via retrograde transport. Tissues are first processed to detect HRP using a tetramethylbenzidine and sodium-tungstate method. Biotinamide or BDA staining is then visualized using an ABC-diaminobenzidine-Ni method and finally the tissue is immunocytochemically stained using choline acetyltransferase (ChAT) or parvalbumin antibodies and a peroxidase-anti-peroxidase method. After processing, biotinamide, BDA, HRP and immunocytochemical staining can readily be distinguished by differences in the size, color and texture of their reaction products. We have utilized this methodology to explore synaptic relationships between trigeminal primary afferent neurons and brainstem projection and motoneurons at both the light and electron microscopic levels. This multiple labeling methodology could be readily adapted to characterize the physiological, morphological and neurochemical properties of other neuronal pathways.

[The effect of heparin on the deep second-degree burn in scalded rats]

OBJECTIVE

To investigate the effects of heparin on deep second-degree burn in scalded rats.

METHODS

Thirty Sprague-Dawley rats inflicted with 20% TBSA deep second-degree scalding on the back were employed as the model and were randomly divided into two groups. i,e heparin (H) and normal saline groups (N). Heparin (100 U . kg(-1) . day(-1)) was injected subcutaneously to the rats in H group while normal saline to those in N group once a day. Wound healing rate and immunological indices were determined simultaneously.

RESULTS

(1) The wound healing time was much shorter in H group than that in N group (P < 0.005). The granulation tissue growth condition examined by LM and EM was much better in H group that than in N group. (2) The lymphocytic transforming ratio in H group was evidently increased (P < 0.005). And the phagocytic function of the macrophages increased significantly (P < 0.05). But there was no difference between the two groups in terms of hemoltytic plaque test (P > 0.05).

CONCLUSION

Injection of heparin subcutaneously could accelerate burn wound healing and strengthen the systemic cellular immune potential and the macrophage phagocytic capacity of the host, but exerted no effect on the humoral immunity.

Exploiting molecular mimicry to broaden the immune response to carbohydrate antigens for vaccine development

Peptide mimetics of carbohydrates represent an alternative approach to induce anti-carbohydrate responses. Depending on their formulation, peptide mimetics can mediate T-independent or T-dependent responses. Multivalent peptide mimeotopes can induce high IgM/IgG ratios, as non-conjugated carbohydrates do. Here we observe that immunization with multivalent peptide mimeotope conjugated to BSA enhances carbohydrate reactive antibodies in Balb/c mice and xid mice, with IgG1 greater than IgG2a, in xid mice. These results suggest that mimeotope-conjugate formulations might augment carbohydrate-specific immune responses in immuno-compromised hosts.

Axonal projections and synapses from the supratrigeminal region to hypoglossal motoneurons in the rat

Neural circuits from the supratrigeminal region (Vsup) to the hypoglossal motor nucleus were studied in rats using anterograde and retrograde neuroanatomical tracing methodologies. Iontophoretic injection of 10% biotinylated dextran amine (BDA) unilaterally into the Vsup anterogradely labeled axons and axon terminals bilaterally in the hypoglossal nucleus (XII) as well as other regions of the brainstem. In the ipsilateral XII, the highest density of BDA labeling was found in the dorsal compartment and the ventromedial subcompartment of the ventral compartment, where BDA labeling formed a dense, patchy distribution. Microinjection of 20% horseradish peroxidase (HRP) ipsilaterally or bilaterally into the tongue resulted in retrograde labeling of XII motoneurons confined to the dorsal and ventral compartments of the hypoglossal motor nucleus. Under light microscopical examination, BDA-labeled terminals were observed closely apposing the somata and primary dendrites of HRP-labeled hypoglossal motoneurons. Two hundred and sixty-five of these BDA-labeled terminals were examined at the ultrastructural level. One hundred and twelve BDA-labeled axon terminals were observed synapsing with either the somata (39%, 44/112) or the large or medium-size dendrites (61%, 68/112) of retrogradely labeled hypoglossal motoneurons. Axon terminals containing spherical vesicles (S-type) formed asymmetric synapses with HRP-labeled hypoglossal motoneuron dendrites. In contrast to this, F(F)-type axon terminals, containing flattened vesicles, formed symmetric synapses with both the somata and dendrites of HRP-labeled hypoglossal motoneurons with a preponderance of the contacts on their somata. Axon terminals containing pleomorphic vesicles (F(P)-type) were noted forming both symmetric and asymmetric synapses with HRP-labeled hypoglossal motoneuron somata and dendrites. The present study provides anatomical evidence of neuronal projections and synaptic connections from the supratrigeminal region to hypoglossal motoneurons. These data suggest that the supratrigeminal region, as one of the premotor neuronal pools of the hypoglossal nucleus, may coordinate and modulate the activity of tongue muscles during oral motor behaviors.

Escape from gene silencing in ICF syndrome: evidence for advanced replication time as a major determinant

Chromosomal abnormalities associated with hypomethylation of classical satellite regions are characteristic for the ICF immunodeficiency syndrome. We, as well as others, have found that these effects derive from mutations in the DNMT3B DNA methyltransferase gene. Here we examine further the molecular phenotype of ICF cells and report several examples of extensive hypomethylation that are associated with advanced replication time, nuclease hypersensitivity and a variable escape from silencing for genes on the inactive X and Y chromosomes. Our analysis suggests that all genes on the inactive X chromosome may be extremely hypomethylated at their 5' CpG islands. Our studies of G6PD in one ICF female and SYBL1 in another ICF female provide the first examples of abnormal escape from X chromosome inactivation in untransformed human fibroblasts. XIST RNA localization is normal in these cells, arguing against an independent silencing role for this RNA in somatic cells. SYBL1 silencing is also disrupted on the Y chromosome in ICF male cells. Increased chromatin sensitivity to nuclease was found at all hypomethylated promoters examined, including those of silenced genes. The persistence of inactivation in these latter cases appears to depend critically on delayed replication of DNA because escape from silencing was only seen when replication was advanced to an active X-like pattern.

Energetics of the interaction between water and the helical peptide group and its role in determining helix propensities

The alanine helix provides a model system for studying the energetics of interaction between water and the helical peptide group, a possible major factor in the energetics of protein folding. Helix formation is enthalpy-driven (-1.0 kcal/mol per residue). Experimental transfer data (vapor phase to aqueous) for amides give the enthalpy of interaction with water of the amide group as approximately -11.5 kcal/mol. The enthalpy of the helical peptide hydrogen bond, computed for the gas phase by quantum mechanics, is -4.9 kcal/mol. These numbers give an enthalpy deficit for helix formation of -7.6 kcal/mol. To study this problem, we calculate the electrostatic solvation free energy (ESF) of the peptide groups in the helical and beta-strand conformations, by using the delphi program and parse parameter set. Experimental data show that the ESF values of amides are almost entirely enthalpic. Two key results are: in the beta-strand conformation, the ESF value of an interior alanine peptide group is -7.9 kcal/mol, substantially less than that of N-methylacetamide (-12.2 kcal/mol), and the helical peptide group is solvated with an ESF of -2.5 kcal/mol. These results reduce the enthalpy deficit to -1.5 kcal/mol, and desolvation of peptide groups through partial burial in the random coil may account for the remainder. Mutant peptides in the helical conformation show ESF differences among nonpolar amino acids that are comparable to observed helix propensity differences, but the ESF differences in the random coil conformation still must be subtracted.

[Study on biodegradation of phenols in river water]

This study on the biodegradation of phenols (phenol, o-methylphenol, o-chlorophenol and resorcinol) in river water was conducted by changing the main influential factors respectively. The results of experiment showed the phenols were greatly degradated in mild temperature, neutral pH and plenty of oxygen and the rank of the phenols biodegradation from great to small was resorcinol, phenol, o-methylphenol and o-chlorophenol. Presented in this paper is also a discussion on the biodegradation mechanism of phenols.

[The effect of heparin on wound healing of second-degree burned rats]

OBJECTIVE

To study the effect of therapeutic effect of heparin on wound healing of second-degree burned rats.

METHODS

Deep second-degree burns with 20% of total body surface were made in 20 rats, which were randomly divided into 2 groups. The experimental group was treated subcutaneously injection with 1 ml of heparin 100 U/kg and saline solution, and the control group was treated with 1 ml of saline solution, once a day until complete healing of the burned wound. The healing time were compared, the growth of granulation tissue and collagen fibers were evaluated under light microscope, and the growth of fibroblasts were observed under electronic microscope.

RESULTS

All rats survived, the healing time of experimental group (22.8 +/- 1.87 days) were much shorter than that of control group (26.2 +/- 2.82 days) (P < 0.005). Light microscope observation showed that the growth of granulation tissue and collagen fibers of experimental group were much better than that of control group, and electronic microscope also showed that the fibroblast growth was obviously better in the experimental group.

CONCLUSION

Subcutaneous injection of heparin can promote wound healing.

Cutting edge: DNA immunization with minigenes of carbohydrate mimotopes induce functional anti-carbohydrate antibody response

To date, the generation of anti-carbohydrate Th1 immune responses, which would be useful for both tumor immunotherapy as well as in pathogen vaccine strategies, has been elusive. To augment Th1 immune responses to carbohydrate Ags, we describe results of DNA vaccination studies in mice using plasmids encoding designed peptide mimotopes (minigenes) of the neolactoseries Ag Lewis Y (LeY). In contrast to LeY immunization, immunization with mimotope-encoded plasmids induced LeY cross-reactive IgG2a Abs. Minigene immunization primed for a LeY-specific response that is rapidly activated upon encounter with nominal Ag upon subsequent boost. The resulting IgG2a response mediated complement-dependent cytotoxicity of a LeY-expressing human tumor cell line in the presence of human complement. These studies establish that peptide mimotopes of carbohydrate Ags encoded as DNA plasmids are novel immunogens providing a means to manipulate carbohydrate cross-reactive Th1 responses.

A molecular basis for functional peptide mimicry of a carbohydrate antigen

Peptides may substitute for carbohydrate antigens in carbohydrate-specific immunological reactions. Using the recognition properties of an anti-Lewis Y (LeY) antibody, BR55-2, as a model system, we establish a molecular perspective for peptide mimicry by comparing the three-dimensional basis of BR55-2 binding to LeY with the binding of the same antibody to peptides. The peptides compete with LeY, as demonstrated by enzyme-linked immunosorbent assay and Biacore analysis. The computer program LUDI was used to epitope map the antibody-combining site, correlating peptide reactivity patterns. This approach identified amino acids interacting with the same BR55-2 functional residue groups that recognize the Fucalpha(1-3) moiety of LeY. Molecular modeling indicates that the peptides adopt an extended turn conformation within the BR55-2 combining site, serving to overlap the peptides with the LeY spatial position. Peptide binding is associated with only minor changes in BR55-2, relative to the BR55-2-LeY complex. Anti-peptide serum distinguishes the Fucalpha(1-3) from the Fucalpha(1-4) linkage, therefore differentiating difucosylated neolactoseries antigens. These results further confirm that peptides and carbohydrates can bind to the same antibody-binding site and that peptides can structurally and functionally mimic salient features of carbohydrate epitopes.

Expression pattern of (+)-delta-cadinene synthase genes and biosynthesis of sesquiterpene aldehydes in plants of Gossypium arboreum L

The cotton (+)-delta-cadinene synthase, a sesquiterpene cyclase, is encoded by a complex gene family which, based on homology, can be divided into two subfamilies: cad1-A and cad1-C. Southern blots revealed several members of the cad1-C subfamily, and a single member of the cad1-A subfamily, in the diploid Gossypium arboreum genome. One of the cad1-C genes, cad1-C3, was isolated from this species. According to reverse transcriptase-polymerase chain reaction, transcripts of both cad1-C and cad1-A genes appeared in roots from the second day post germination and in 1-d-old cotyledons, whereas the transcription levels were too low to be detected in the hypocotyls. Initially, sesquiterpene cyclase activities were found to be high in the seedlings, then dropped in aerial organs but increased in roots during development. Sesquiterpene aldehyde contents followed the same pattern. In fully developed plants, the transcripts of cad1-C were detected in stems, leaves and pericarps, as well as in the sepals and petals 3 d before anthesis, but not at the day of anthesis. In contrast, cad1-A transcripts were not detected in any of these aerial organs. The sesquiterpene aldehyde contents increased in petals but decreased in sepals after anthesis. Treatment of G. arboreum stems with a Verticillium dahliae elicitor-preparation activated cad1-A transcription, but a significant level of cad1-C transcripts was detected both before and after elicitation. In G. hirsutum cv. GL-5, a glandless cultivar, the cad1-C gene was activated by the same fungal elicitor, followed by the synthesis of the sesquiterpene cyclase, and accumulation of sesquiterpene aldehydes. The cad1 gene expression during development and in response to elicitation, as well as the spatial and temporal pattern of sesquiterpene biosynthesis, constitute a chemical defense machinery in cotton plants.

The DNMT3B DNA methyltransferase gene is mutated in the ICF immunodeficiency syndrome

DNA methylation is an important regulator of genetic information in species ranging from bacteria to humans. DNA methylation appears to be critical for mammalian development because mice nullizygous for a targeted disruption of the DNMT1 DNA methyltransferase die at an early embryonic stage. No DNA methyltransferase mutations have been reported in humans until now. We describe here the first example of naturally occurring mutations in a mammalian DNA methyltransferase gene. These mutations occur in patients with a rare autosomal recessive disorder, which is termed the ICF syndrome, for immunodeficiency, centromeric instability, and facial anomalies. Centromeric instability of chromosomes 1, 9, and 16 is associated with abnormal hypomethylation of CpG sites in their pericentromeric satellite regions. We are able to complement this hypomethylation defect by somatic cell fusion to Chinese hamster ovary cells, suggesting that the ICF gene is conserved in the hamster and promotes de novo methylation. ICF has been localized to a 9-centimorgan region of chromosome 20 by homozygosity mapping. By searching for homologies to known DNA methyltransferases, we identified a genomic sequence in the ICF region that contains the homologue of the mouse Dnmt3b methyltransferase gene. Using the human sequence to screen ICF kindreds, we discovered mutations in four patients from three families. Mutations include two missense substitutions and a 3-aa insertion resulting from the creation of a novel 3' splice acceptor. None of the mutations were found in over 200 normal chromosomes. We conclude that mutations in the DNMT3B are responsible for the ICF syndrome.

[Identification of Panax quinquefolius, P. ginseng and P. notoginseng by protein fingerprints]

Establish the way of protein fingerprints to identify P. quinquefolius, P. ginseng and P. notoginseng of genus Panax by SDS-PAGE, Tris-tricine and Western blot. The fingerprints of Panax species from 28 KD to 58 KD and 55 KD are in common. Very different fingerprints of P. quinquefolius are found below 28 KD. The fingerprints above 58 KD seemed to be peculiar for P. ginseng. Hence the approach may be used as a means to authenticate the concerned Panax species, especially for identification of P. quinquefolius.

Jaw-muscle spindle afferent feedback to the cervical spinal cord in the rat

Putative synaptic contacts between masticatory-muscle spindle afferents and brainstem neurons which project to the cervical spinal cord were studied in rats by combining retrograde and intracellular neuronal labeling. Spinal cord projecting neurons were retrogradely labeled via injection of horseradish peroxidase unilaterally or bilaterally into cervical spinal cord segments C2 through C5. Twenty-four hours after the injection of horseradish peroxidase, one to five jaw-muscle spindle afferent axons were physiologically identified and intracellularly stained with biotinamide on each side of the brainstem. Horseradish-peroxidase-labeled neurons were found bilaterally in the supratrigeminal region, trigeminal principal sensory nucleus, parvicellular reticular nucleus including its alpha division, spinal trigeminal subnuclei oralis and interpolaris and the medullary reticular formation. Retrogradely labeled neurons were most numerous in the spinal trigeminal subnucleus oralis, parvicellular reticular formation and the ventral part of the spinal trigeminal subnucleus interpolaris. A small number of horseradish-peroxidase-labeled neurons were also present in the trigeminal mesencephalic nucleus and spinal trigeminal subnucleus caudalis. Appositions between jaw-muscle spindle afferent boutons and spinal projecting neurons were found in the supratrigeminal region, dorsomedial portions of the trigeminal principal sensory nucleus and spinal trigeminal subnuclei oralis and interpolaris, and the parvicellular reticular formation including its alpha division. Putative synaptic contacts were most frequent in the parvicellular reticular formation and the dorsomedial portion of the trigeminal subnucleus oralis. These results indicate that some orofacial proprioceptive feedback transmitted via the mesencephalic trigeminal nucleus reaches the cervical spinal cord directly and suggests that jaw-muscle spindle afferent feedback reaches the cervical spinal cord predominately via relays in the dorsomedial part of the spinal trigeminal subnucleus oralis and the parvicellular reticular formation. It is hypothesized that these pathways are primarily involved in the coordination of jaw and neck movement during mastication and biting.

Vaccination with carbohydrate peptide mimotopes promotes anti-tumor responses

Tumor-associated carbohydrate (TAC) antigens are important targets in cancer vaccine efforts. Carbohydrates are, however, frequently poor immunogens, in that they are T-cell-independent antigens. Molecular mimicry of TAC by peptides is an alternative approach to generating anti-carbohydrate immune responses. Here we demonstrate that peptide mimotopes can elicit antibody responses that cross-react with representative human TAC antigens. Primary immunization with such a multiple antigenic peptide, along with QS-21 as adjuvant, elicits cytotoxic antibodies reactive with naturally occurring forms of TAC expressed on tumor cells, and vaccination of mice with peptide mimotopes reduced tumor growth and prolonged host survival in a murine tumor model.

Analysis of the capacity of extracts from normal human young and senescent fibroblasts to support DNA synthesis in vitro

Cytoplasmic extracts from early-passage (young), late-passage (senescent) normal human fibroblast (HF) cultures and immortalized human cell lines (HeLa, HT-1080, and MANCA) were analyzed for their ability to support semiconservative DNA synthesis in an in vitro SV40-ori DNA replication system. Unsupplemented extracts from the three permanent cell lines were demonstrated to be active in this system; whereas young HF extracts were observed to be minimally active, and no activity could be detected in the senescent HF extracts. The activity of these extracts was compared after supplementation with three recombinant human replication factors: (1) the catalytic subunit of DNA polymerase alpha (DNA pol-alpha-cat), (2) the three subunits of replication protein A (RPA), and (3) DNA topoisomerase I (Topo I). The addition of all three recombinant proteins is required for optimum activity in the young and senescent HF extracts; the order of the level of activity is: transformed > young HF > senescent HF. Young HF extracts supplemented with RPA alone are able to support significant replicative activity but not senescent extracts which require both RPA and DNA pol-alpha-cat for any detectable activity. The necessary requirement for these factors is confirmed by the failure of unsupplemented young and senescent extracts to activate MANCA extracts that have been immunodepleted of DNA pol-alpha-cat or RPA. Immunocytochemical studies revealed that RPA, DNA pol-alpha, PCNA, and topo I levels are higher in the immortal cell types used in these studies. In the HF cells, levels of DNA pol-alpha-cat and PCNA are higher (per mg protein) in the low-passage than in the senescent cells. By contrast, RPA levels, as determined by immunocytochemical or Western blot studies, were observed to be similar in both young and senescent cell nuclei. Taken together, these results indicate that the low to undetectable activity of young HF extracts in this system is due mainly to reduced intracellular levels of RPA, while the senescent HF extracts are relatively deficient in DNA polymerase alpha and probably some other essential replication factors, as well as RPA. Moreover, the retention of RPA in the senescent HF nuclei contributes to the low level of this factor in the cytoplasmic extracts from these cells.

Interaction between water and polar groups of the helix backbone: an important determinant of helix propensities

We report an enthalpic factor involved in determining helix propensities of nonpolar amino acids. Thermal unfolding curves of the five 13-residue peptides, Ac-KA4XA4KGY-NH2 (X = Ala, Leu, Ile, Val, Gly), have been measured by using CD in water/trifluoroethanol (TFE) mixtures. The peptide helix contents show that the rank order of helix propensities changes with temperature: although Ala has the highest helix propensity at 0 degrees C in all TFE concentrations, it is lower than Leu, Ile, and Val at 50 degrees C in 20% TFE. This change is attributed to shielding by nonpolar side chains of the interaction between water and polar groups in the helix backbone for the following reasons. (i) Helix content is directly related to helix propensity for these designed peptides because side-chain-side-chain interactions are absent. (ii) The change in rank order with temperature is enthalpic in origin: in water, the apparent enthalpy of helix formation calculated from the thermal unfolding curves varies widely among the five peptides and has the same rank order as the helix propensities at 0 degrees C. The rank order does not result from burial of nonpolar surface area because the calculated heat capacity change (DeltaCp) on helix formation is opposite in sign from the expected DeltaCp. (iii) A nonpolar side chain can exclude water from interacting with helix polar groups, according to calculations of water-accessible surface area, and the polar interaction between water and peptide polar groups is entirely enthalpic, as shown by amide transfer data.

Ultrastructural anatomy of physiologically identified jaw-muscle spindle afferent terminations onto retrogradely labeled jaw-elevator motoneurons in the rat

Neuronal microcircuits involving jaw-muscle spindle afferents and jaw-elevator motoneurons were studied via retrograde and intracellular labeling in rats. Initially, trigeminal motoneurons were retrogradely labeled from horseradish peroxidase (HRP) injections into the temporalis and masseter muscles. The intracellular response of jaw-muscle spindle afferent neurons was then characterized during palpation, ramp and hold, and sinusoidal stretching of the jaw-closing muscles. Biotinamide was injected into these neurons, and the tissue was processed for the visualization of HRP and biotinamide. The ultrastructure of 243 intracellularly stained jaw-muscle spindle afferent boutons located within the trigeminal motor nucleus (Vmo) was examined. Eighty-five of these boutons synapsed with motoneurons retrogradely labeled with HRP, and 158 boutons synapsed with unlabeled structures within the Vmo. All spindle afferent boutons contained clear, spherical synaptic vesicles. Although the majority of boutons were S type, a few labeled jaw-muscle spindle afferent boutons possessed a long, narrow cleft, with a subsynaptic cistern comparable to previous descriptions of C-type boutons. Sixty-eight percent of spindle afferent boutons synapsed with large or medium-sized, retrogradely labeled motoneuron dendrites, and 32% synapsed with retrogradely labeled somata. In numerous instances, spindle afferent boutons synapsed with trigeminal motoneuron dendritic or somatic spines. Most of the synapses between spindle afferent boutons and trigeminal motoneuron dendrites were asymmetric, and the greatest percentage of axosomatic synapses between spindle afferents and trigeminal motoneurons were symmetric. Approximately 24% of spindle afferent boutons constituted the intermediate element of a axoaxodendritic or axoaxosomatic assemblage, implying that some jaw-muscle spindle afferent synapses with trigeminal motoneurons are presynaptically modulated.

Towards the development of peptide mimotopes of carbohydrate antigens as cancer vaccines

Tumor-associated carbohydrate antigens are considered important targets in efforts to develop cancer vaccines. To further enhance vaccine efforts, we are developing peptide mimotopes of tumor-associated carbohydrate antigens that can elicit functional immune responses. Mapping peptide epitopes with anticarbohydrate antibodies can lend to defining structural relationships that can go undetected by screening of carbohydrate antigens alone. Here we contrast reactivity patterns for peptides using monoclonal antibodies (MAbs) directed to the neolactoseries related Lewis Y (LeY) and sialyl-Lewis X (sLeX) antigen and the GD3/GD2 ganglioside antigen. We observe that representative MAbs cross-react with a WRY-containing peptide and that this motif type is isolated by the respective monoclonal in peptide phage display screening. Primary immunization with multiple antigen peptide preparations with QS-21 adjuvant efficiently elicited cytotoxic IgM antibodies for a murine Meth A fibrosarcoma line expressing sLeX. The cytotoxicity of IgG polyclonal response was found to be as effective as IgM in mediating complement-dependent cytotoxicity against the Meth A line. These experiments suggest that peptide mimotopes of the LeY and sLeX tumor-associated carbohydrate antigen and QS-21 adjuvant could be considered as an immunogenic therapeutic vaccine in carcinoma and melanoma patients in the minimal residual disease setting.

Antigenic and immunological mimicry of peptide mimotopes of Lewis carbohydrate antigens

Peptides may substitute for carbohydrates in reactions with carbohydrate-specific molecules. Recently, we found that peptides containing aromatic residues mimic mucin and histo-blood group related carbohydrate epitopes, eliciting polyclonal responses cross-reactive with bacterial and viral antigens that express these carbohydrate forms. These results demonstrate that peptides can function in in vivo and in vitro models as carbohydrate surrogate antigens. To further explore the nature of the antigenic and immunogenic properties of such mimotopes, synthetic peptides with aromatic amino acids were tested to delineate reactivity patterns with several anti-neolactoseries monoclonal antibodies (MAbs). These MAbs recognize biologically important conformations of the histo-blood group related Lewis antigens expressed on the surface of a variety of human cancers. Results by ELISA demonstrate that the MAbs can distinguish particular peptide motifs that include the sequences GGIYYPYDIYYPYDIYYPYD, GGIYWRYDIYWRYDIYWRYD and GGIYYRYDIYYRYDIYYRYD. Substitution of Arg by Pro diminished the reactivity of the anti-Lewis Y (LeY) MAb BR55-2. Binding of LeY to BR55-2 was inhibitable by the Arg containing peptides. Serum against all three peptides displayed reactivity with synthetic histo-blood group related antigen probes. Immunologic presentation of the peptides as multiple antigen peptides (MAPs) improved peptide ability to induce LeY specific immune responses. Serum bound to human tumor cells that preferentially expressed neolactoseries antigens, but not to normal tissues. Immunoprecipitation of human breast tumor cell lysates before and after treatment with tunicamycin confirmed serum carbohydrate binding. The anti-peptide sera mediated tumor cell killing by complement mediated cytotoxicity. These results indicate that mapping peptide epitopes with anti-carbohydrate antibodies can lend to defining antibody fine specificities that can go undetected by screening of carbohydrate antigens alone. In addition, these results confirm that peptides and carbohydrates can bind to the same antibody binding site and that peptides can structurally mimic salient features of carbohydrate epitopes.

[Study on inhibition and prevention of tumor and antioxidative effects of lithium carbonate in tumor bearing mice]

Two Kinds of tumor-bearing mice (hepatoma H22 and sarcoma S180) were administered with lithium carbonate (Li2CO3) for 17 or 10 days (advanced and simultaneous administration), in order to observe the effects of prevention and treatment of Li2CO3 on malignant tumor, as well as the relationship between Li2CO3 and lipid peroxidation in tumor-bearing mice. Meanwhile, we compared the toxic and side effects of cyclophosphamide (CP) with that of Li2CO3. The results showed that Li2CO3 had no significant toxic or side effects with the suggested doses. In the tests of inhibition and prevention of tumor, Li2CO3 could significantly inhibit the grouth of the two kinds of tumor, and increase the activity of superoxide dismutage (SOD) and decrease the contents of Malonyldialdehyde (MDA). In addition, Li2CO3 had no effect on the white blood cells (WBC) and decreased the micronucleus frequency (MNF) in bone marrow polychromatic erythrocytes (PCE), while CP had definite effect of decreasing the WBC and increasing the MNF in the tumor-bearing mice.

X-ray lens of monolithic polycapillaries for macromolecular crystallography

The monolithic polycapillary X-ray Lens is a fast developing optics that has many applications in different fields, one of them, described in this paper, is a successful application in the X-ray diffraction for macromolecular crystallography. The direct beam intensity irradiating on crystal with usage of the monolithic X-ray lens was increased 1 to 2 order of magnitude more than the traditional method with the double focusing mirrors. the diffracted X-ray intensity was increased more than about 8 times, the resolution was improved by 0.2–0.6Å, and the signal to noise ratio was also improved. The measuring time became shorter. The crystal samples which had to be analyzed by synchrotron before are able to be investigated in routine laboratory now.

Mechanism of helix induction by trifluoroethanol: a framework for extrapolating the helix-forming properties of peptides from trifluoroethanol/water mixtures back to water

To establish a framework for extrapolating the helix-forming properties of peptides from TFE/H2O mixtures (TFE = 2,2, 2-trifluoroethanol) back to water, the thermal unfolding curves have been measured by circular dichroism for four repeating-sequence peptides, with chain lengths from 7 to 22 residues. The unfolding curves were measured between 0 and 50 volume percent TFE and were fitted to the modified Lifson-Roig theory. A single set of helix-coil parameters fits the results for the four peptides at each TFE concentration; only two of the basic helix-coil parameters, <w>, the mean helix propagation parameter of residues in the sequence repeat, and DeltaH, the enthalpy change per residue on unfolding the helix, are allowed to vary with TFE molarity. The success in fitting these curves over a wide range of experimental variables shows that helix formation is basically the same in TFE/H2O mixtures as in water. Moreover, a simple model based on a linear dependence of ln <w> and DeltaH on TFE molarity can be used to extrapolate the results from 25% TFE (approximately 4 M) back to water. The results also give curves of helix formation induced by TFE at constant temperature, and the properties of these helix induction curves explain some of the puzzling results shown by other peptides in the literature. The average helix propensity increases regularly from 0 to 25% TFE but levels off at higher TFE concentrations, which explains why the extent of helix formation levels off in this range. The change in the apparent cooperativity of thermal unfolding curves in concentrated TFE solutions results from the decrease of the enthalpy change for helix unfolding at higher TFE concentrations. The rapid decrease in the plateau values of apparent helix content with increasing temperature results mainly from the strong temperature dependence of the ellipticity of the complete helix. To determine whether the helix-stabilizing effect of TFE arises from strengthening the hydrogen bonds in the helix backbone, the strength of the hydrogen bond in a model compound, salicylic acid, has been measured in TFE/H2O mixtures from the pKa difference between salicylic acid and a similar compound which cannot form the hydrogen bond. The curve of hydrogen bond strength versus increasing TFE concentration matches both in shape and magnitude the increase in average helix propensity in TFE/H2O mixtures.

Peptide mimicry of carbohydrate epitopes on human immunodeficiency virus

Cancer-related, mucin-type carbohydrate epitopes, principally mannose and sialo-syl residues, are expressed on the envelope protein gp 160 of the human immunodeficiency virus (HIV). Anticarbohydrate antibodies directed toward these and other carbohydrate epitopes are known to neutralize HIV-1 infection by cell-free virus. Carbohydrates, however, being T cell-independent antigens, typically elicit diminished immune responses. To overcome this potential draw back, we have examined the ability of peptides that mimic such epitopes to elicit immune responses that cross-react with carbohydrate structures. We report that mouse polyclonal antisera generated against peptides that mimic mucin-related carbohydrate epitopes have anti-HIV-1 activity. Generation of antibodies was not lr-gene restricted, as at least two different strains of mice. Balb/c (H-2d) and C57Bl/6 (H-2b), responded equally to the peptides. The antipeptide sera displayed neutralizing activity against HIV-I/MN and HIV-I/3B viral strains. This neutralization was as good as human anti-HIV sera. These results indicate that peptide mimics of carbohydrates provide a novel strategy for the further development of reagents that elicit immune responses to carbohydrate epitopes associated with many infectious organisms and tumor cells.

Primary- and secondary-like jaw-muscle spindle afferents have characteristic topographic distributions

Single jaw-muscle spindle afferent axons were characterized physiologically and intracellularly stained to determine whether particular physiological types of spindle afferent show distinctive morphologies. Microelectrodes filled with either horseradish peroxidase (HRP) or biotinamide (Neurobiotin) were advanced into the mesencephalic trigeminal nucleus (Vme) in anesthetized rats. Intracellular recordings then were characterized by their response: to palpation of the jaw muscles; when pressure was applied to the teeth and during passive ramp and hold and sinusoidal jaw movement. Seventy-one afferents were characterized physiologically and injected with HRP; an additional 61 afferents were typed and injected with biotinamide. The response of 43 stained neurons was recorded in the presence of suxamethonium. The major projection areas of these afferents were the: trigeminal motor nucleus (Vmo); region dorsal to Vmo; reticular formation, spinal trigeminal nucleus, superior cerebellar peduncle and Vme. One afferent type was modulated strongly during stretching of the jaw-elevator muscles. Based on their high sensitivity during stretching of the jaw muscles and/or their silencing during the release phase of muscle stretch, these afferents were classified as primary-like spindle afferents. These afferents projected most strongly to Vmo. A second type of afferent was modulated only modestly during stretching of the jaw-elevator muscles. These tonic afferents were classified as secondary-like spindle afferents because of their low dynamic sensitivity during ramp muscle stretch and their continued discharge during the release phase of muscle stretch. Secondary-like afferents projected most strongly to the region dorsal to Vmo. Boutons (n = 3,834) from 11 afferents were studied in detail. Secondary-like afferents had statistically larger boutons within Vmo. In both secondary- and primary-like spindle afferents, only a small number of boutons were associated closely with the somata and proximal dendrites of trigeminal motoneurons. In these cases, however, two to five boutons appeared to contact individual motoneurons, implying multiple monosynaptic inputs to a selective subset of jaw-elevator motoneurons. Some "giant" boutons were present dorsal to Vmo and in Vme. These results demonstrate that dynamically sensitive and nondynamically sensitive jaw-elevator muscle spindle afferents project preferentially to different regions. Primary-like spindle afferents are capable of providing feedback related to the dynamic phases of muscle stretch and project most heavily to Vmo. Secondary-like spindle afferents can transmit a feedback signal associated with muscle length and project most strongly to the supratrigeminal region. Both types of afferent have projections caudal to Vmo that may serve longer latency jaw-muscle stretch reflexes and/or the projection of proprioceptive information to the thalamus and cerebellum.

The tension-stress effects on growth of the external anal sphincter: animal experiment and its application on treatment of anorectal stenosis

OBJECTIVE

To evaluate the effect of continuous balloon distension on the treatment of anorectal stenosis.

METHODS

Animal experiment on 17 guinea pigs and clinical study on 13 patients with anorectal stenosis were carried out. The procedure of the continuous balloon distension was followed to stimulate the growth of the anus or stenotic segment.

RESULTS

In animal experiment, the procedure induced muscle growth of the external anal sphincter at a rate of 2 mm per day. The grown muscle showed good contractile ability. By histological examination, it was found that the muscle cells were hypertrophic and Schwann's cells of the nerve fibers in the muscle became hyperplastic. Under electron-microscope, the muscle sarcomeres were found splitting both transversely and longitudinally. Twelve of the 13 patients were successfully treated by continuous balloon distension within 5 to 15 days (average: 6.7 days). During 4 to 14 months follow-up, all patients defecated without difficulty.

CONCLUSIONS

Continuous balloon distension may induce growth of the external anal sphincter. This procedure is an acceptable therapy for anorectal stenosis.

Peptide mimicry of adenocarcinoma-associated carbohydrate antigens

Carbohydrate antigens have been identified as significant antigens in many human tumors either by analyzing antibodies in patients' sera or by using monoclonal antibodies of either mouse or human origin. Three carbohydrate epitopes present on cancer-associated mucins [sialyl-Lewis A (SLA), sialyl-Lewis X (SLX), and sialyl-Tn (STn)] may have functional significance in metastasis. Subsequently, these antigens are considered as targets for active specific immunotherapy. Carbohydrates, as T-cell-independent antigens, often elicit diminished immune responses. To overcome this drawback, carbohydrates are typically coupled to protein carriers to elicit immunoglobulin G (IgG) responses as opposed to low-affinity IgM responses, which often times accompanies carbohydrate-based immunizations. In addition, some complex carbohydrates are difficult to synthesize. This latter aspect is further magnified if one considers that clustering of epitopes on neoglycoproteins must be emulated in the synthesis process, leading to multiple presentation or tandem repeats of the synthetic carbohydrate immunogen. Here, we examine the hypothesis that peptides that mimic carbohydrates might be developed to induce immune responses that target and mediate the killing of tumor cells, particularly breast cancer cells in an adjuvant-type setting. We have found that carbohydrate-mimicking peptides retain carbohydrate-like conformations, inducing anti-carbohydrate immune responses against breast tumor cells and mediating their killing by a complement-dependent mechanism.

[The change of trace elements content in hair during the period of gestation]

Study on trace elements content change in hair during the period of gestation for 52 lying-in women was performed. The quantitative results for 7 elements have been obtained and the change tendencies for other 7 elements without standard value have been observed on the basis of a self comparison method for each individual.

Preparing hydroxyapatite powders with controlled morphology

We developed a synthesis method for hydroxyapatite particles with different morphologies. The process involved chemical precipitation and spray drying, which produced spherical, agglomerated hydroxyapatite granules with controlled particle sizes and structures. These granules contained nanoparticles with an average crystalline size of about 10 nm. We controlled the morphologies of the granules by adjusting the spray-drying conditions, such as the volume fraction of feed slurry and the atomization pressure. The spray-dried granules were doughnut shapes, solid spheres, or hollow spheres, and their sizes were controlled by varying the atomization pressure and the concentration of the feed slurry.

Potential role of the inactivated X chromosome in ovarian epithelial tumor development

BACKGROUND

Ovarian epithelial tumors can be divided into subcategories often regarded as different stages of neoplastic transformation. Cystadenomas belong to the least aggressive subgroup and are noninvasive and nonmetastatic. Ovarian tumors of low malignant potential (LMP) are intermediate between cystadenomas and carcinomas and show markedly reduced invasive and metastatic abilities. Invasion and metastasis are the hallmarks of carcinomas, which constitute the most aggressive subgroup and can be further subdivided into different grades.

PURPOSE

We performed comparative allelotype analyses of ovarian cystadenomas, LMP tumors, and carcinomas, reasoning that such analyses could provide clues about the molecular determinants of their phenotypic differences. Because we realized that allelic losses involving the X chromosome might be associated with LMP tumor development, we determined whether such losses were interstitial and whether they involved the active or the inactive X chromosome.

METHODS

Frequencies of loss of heterozygosity (LOH) at specific loci in every chromosomal arm were determined in 16 ovarian cystadenomas, 23 ovarian LMP tumors, 15 low-grade ovarian carcinomas, and 35 high-grade ovarian carcinomas by use of either the polymerase chain reaction (PCR) or Southern blot analyses. We took advantage of the fact that DNA methylation is an important mechanism of X-chromosome inactivation to determine whether losses involving the X chromosome were in the active or the inactive copy. We analyzed the methylation status of retained alleles on the X chromosome by determining whether they could be amplified by PCR after digestion with the methylation-sensitive restriction endonuclease Hpa II.

RESULTS

High-grade carcinomas contained frequent(>50%) LOH in four autosomal chromosome arms, i.e., 6q, 13q, 17p, and 17q. Except for 13q, these same chromosomal arms showed frequent LOH in low-grade carcinomas. LOH in autosomal chromosomes was comparatively rare in LMP tumors and was absent in cystadenomas. In contrast, half (eight of 16) of LMP tumors informative for a locus in the proximal portion of chromosome Xq showed LOH at that locus. These losses were the result of interstitial deletions in six of the eight cases and involved the inactive copy of the X chromosome exclusively. Similar losses in the X chromosome were not seen in either cystadenomas or low-grade carcinomas.

CONCLUSIONS AND IMPLICATIONS

LOH at multiple loci is associated with the development of ovarian carcinomas but not with the development of cystadenomas and LMP tumors. However, the integrity of a locus in chromosome Xq that possibly escapes X-chromosome inactivation is important for the control of LMP tumor development. The fact that this locus does not appear to be involved in the genesis of low-grade carcinomas suggests that LMP tumors are not precursors of such carcinomas.

Morphological evidence for recurrent jaw-muscle spindle afferent feedback within the mesencephalic trigeminal nucleus

Horseradish peroxidase was injected into the jaw-elevator muscles of rats. Jaw-muscle spindle afferent axons were then intracellularly stained with biotinamide. Eleven intracellularly stained somata were closely apposed by intracellularly labeled spindle afferent boutons. Spindle afferent boutons closely apposed another 10 mesencephalic trigeminal nucleus (Vme) perikarya labeled from the jaw muscles. These results indicate that an anatomical substrate exists for recurrent feedback between jaw-muscle spindle afferents within Vme.

Transneuronal transport of intracellularly injected biotinamide in primary afferent axons

Transneuronal transport of biotinamide was observed following intracellular injection of biotinamide into rat jaw-muscle spindle afferent axons. Microelectrodes were advanced into the mesencephalic nucleus of the trigeminal nerve where jaw-muscle spindle afferent axons were identified by their increased firing during stretching of the jaw-elevator muscles. Biotinamide (Neurobiotin) was then injected into individual axons and the animals were maintained under anesthesia for 2-6 h. The animals were then killed via an overdose of anesthetic and the brainstem was processed histochemically. Biotinamide-filled axon collaterals and terminals were readily visible in the trigeminal motor nucleus, the trigeminal sensory nuclei, and adjacent reticular formation. In addition to these intracellularly stained axons, two to five neurons per animal (total of 36 in eight rats) were observed with a homogeneous gray reaction product distributed throughout their somata, proximal, and secondary dendrites. These neurons ranged in size from small (8-20 mu m, n - 26) to medium-sized (<30 mu m, n = 10) and were closely apposed by numerous (up to 20) biotinamide-stained spindle afferent boutons. Most of these neurons (n = 22) were located in the dorsomedial portion of the spinal trigeminal subnucleus interpolaris (Vi) 2.5-4.5 mm caudal to the intra-axonal injection site. Electron microscopic analysis in two rats suggests that the transneuronal biotinamide labeling occurred predominantly through asymmetric, axodendritic synapses between biotinamide-filled axon terminals and Vi neuronal dendrites. Although recent in vitro studies have reported that biotinamide permeates through gap junctions, in this study we found no evidence of biotinamide traversing the gap junctions which exist between trigeminal mesencephalic nucleus (Vme) neuronal somata. These results demonstrate that biotinamide can occasionally be transneuronally transported presumably via synapses; further information is needed to explain the seemingly sporadic nature of this transport.

Ultrastructural basis for synaptic transmission between jaw-muscle spindle afferents and trigeminothalamic neurons in the rostral trigeminal sensory nuclei of the rat

Trigeminothalamic neurons were retrogradely labeled by injection of horseradish peroxidase into the ventroposteromedial nucleus of the thalamus in rats. Jaw-muscle spindle afferent axons were then physiologically identified and intracellularly stained with biotinamide. The ultrastructure of labeled spindle afferent boutons was then studied in the caudolateral supratrigeminal region (Vsup) and dorsomedial trigeminal principal sensory nucleus (Vpdm). A total of 418 stained spindle afferent boutons were identified in Vsup and Vpdm; approximately 75% of these synapsed with dendrites, 10% synapsed with somata, and 15% synapsed with axons. Most jaw-muscle spindle afferent boutons were postsynaptic to unlabeled P-type boutons. Reciprocal synapses between spindle afferent boutons and unlabeled boutons were occasionally observed. A few dendrites in Vsup and Vpdm received synapses from multiple spindle afferent boutons. Conversely, some large (from 3 x 6 to 4 x 8 microns) and giant (from > 4 x 8 to 5 x 10 microns) spindle afferent boutons simultaneously contacted two to five dendrites and/or somata. Jaw-muscle spindle afferent boutons also formed synapses with retrogradely labeled trigeminothalamic neurons in Vsup and Vpdm. Numerous unlabeled S-and F-type boutons converged onto the same trigeminothalamic dendrite or soma contacted by a spindle afferent bouton. A small number of synaptic triads consisting of an unlabeled P-type bouton, a spindle afferent bouton, and either a dendrite or soma were also encountered. These data indicate that sensory feedback from the masticatory muscles is subject to presynaptic inhibition and integration prior to reaching the thalamus. This pathway is likely to be important in the relay of proprioceptive and kinesthetic information from the muscles of mastication to the thalamus.

Projection of jaw-muscle spindle afferents to the caudal brainstem in rats demonstrated using intracellular biotinamide

Intracellular staining with biotinamide was used to study the axonal projection and synaptic morphology of rat jaw-muscle spindle afferents. Intracellular recordings in the mesencephalic trigeminal nucleus (Vme) were identified as spindle afferent responses by their increased firing during stretching of the jaw-elevator muscles. Biotinamide-stained axon collaterals with boutons were found in the trigeminal motor nucleus (Vmo), Vme, the region dorsal to Vmo including the supratrigeminal region, the dorsomedial portion of the trigeminal principal sensory nucleus, and the dorsomedial part of the rostral spinal trigeminal subnucleus oralis. Additional, previously undescribed projections of jaw-muscle spindle afferents were found to the dorsomedial portion of the caudal spinal trigeminal subnucleus oralis (Vodm), the dorsomedial part of the spinal trigeminal subnucleus interpolaris (Vidm), the caudal parvicellular reticular formation, laminae IV and V of the spinal trigeminal subnucleus caudalis (Vc), and the dorsal division of the medullary reticular field. Labeled spindle boutons in Vodm formed predominately axodendritic synapses. Some of these boutons received presynaptic inputs from unlabeled P-type boutons containing clear, spherical, or flattened vesicles. In Vidm, labeled collaterals and boutons were densely clustered into glomerular-like structures. Labeled boutons in Vidm made axodendritic, axosomatic, and axoaxonic synapses and received synaptic contacts from unlabeled boutons containing clear, spherical, or flat and pleomorphic vesicles. Unlabeled presynaptic boutons in Vidm occasionally contained dense core vesicles. Labeled boutons in Vc mainly formed synaptic contacts with large diameter dendrites. This projection of jaw-muscle spindle afferents to caudal brainstem regions may play a significant role in masticatory-muscle stretch reflexes and in the integration of trigeminal proprioceptive information and its transmission to higher centers.

Production and cytogenetics of intergeneric hybrids between Brassica napus and Orychophragmus violaceus

The intergeneric hybrid between Brassica napus and Orychophragmus violaceus was obtained by means of embryo culture technique with the latter as the pollen parent. The hybrid was morphologically intermediate between its parents, but could produce a lot of seeds when selfed. Somatic separation of the genomes from the two parental species was observed during the mitotic divisions of some of the hybrid cells. Thus, the hybrid became the mixoploid in nature, consisting of haploid and diploid cells of B. napus, and a nuclear - cytoplasmic hybrid, with the cytoplasm of B. napus and the nuclei of O. violaceus, and the hybrid cells. Pollen mother cells with 19, 12 and 6 bivalents, respectively, were produced by the hybrid. From the selfed progeny of the hybrid, mainly two kinds of plants, B. napus and the hybrid, were found. The hybrid plants of the selfed progeny again produced two kinds of plants, B. napus and the hybrid.

Inputs from identified jaw-muscle spindle afferents to trigeminothalamic neurons in the rat: a double-labeling study using retrograde HRP and intracellular biotinamide

Projections from physiologically identified jaw-muscle spindle afferents onto trigeminothalamic neurons were studied in the rat. Trigeminothalamic neurons were identified by means of retrograde transport of horseradish peroxidase from the ventroposteromedial nucleus of the thalamus. Labeled neurons were found contralaterally in the supratrigeminal region (Vsup), the trigeminal principal sensory nucleus, the ventrolateral part of the trigeminal subnucleus oralis, the spinal trigeminal subnuclei interpolaris and caudalis, the reticular formation, and an area ventral to the trigeminal motor nucleus (Vmo) and medial to the trigeminal principal sensory nucleus (AVM). Jaw-muscle spindle afferents were physiologically identified by their increased firing during stretching of the jaw muscles and intracellularly injected with biotinamide. Axon collaterals and boutons from jaw-muscle spindle afferents were found in Vmo; Vsup; the dorsomedial part of the trigeminal principal sensory nucleus (Vpdm); the dorsomedial part of the spinal trigeminal subnuclei oralis, interpolaris (Vidm) and caudalis; the parvicellular reticular formation (PCRt); and the mesencephalic trigeminal nucleus. Trigeminothalamic neurons in Vsup, Vpdm, Vidm, PCRt, and AVM were associated with axon collaterals and boutons from intracellularly stained jaw-muscle spindle afferents. Trigeminothalamic neurons in Vsup, Vpdm, Vidm, and PCRt were closely apposed by one to 14 intracellularly labeled boutons from jaw-muscle spindle afferents, suggesting a powerful input to some trigeminothalamic neurons. These data demonstrate that muscle length and velocity feedback from jaw-muscle spindle afferents is projected to the contralateral thalamus via multiple regions of the trigeminal system and implicates these pathways in the projection of trigeminal proprioceptive information to the cerebral cortex.

Structural and thermodynamic characterization of a bioactive peptide model of apolipoprotein E: side-chain lactam bridges to constrain the conformation

Apolipoprotein E plays a critical role in plasma lipoprotein clearance. A peptide model of a highly conserved domain of this protein has been shown to increase low-density lipoprotein binding to fibroblast cell surface receptors. To distinguish between two potential structures--one essentially alpha-helical and nonamphiphilic, the other an amphiphilic pi-helix--synthetic side-chain lactam constraints have been incorporated into model peptides in order to restrict conformational flexibility favoring either the alpha- or pi-helix. Here we provide CD and 1H NMR data suggesting that the more biologically active, putatively alpha-helical peptide indeed contains two alpha-helical domains separated by a central bend. Whereas previous studies (Osapay & Taylor, 1992; Felix et al., 1988) indicated stabilization of alpha-helices by cross-links between the i and i + 4 residues, the current paper demonstrates that cross-links between the i and i + 3 residues also stabilize the helix. Indeed, the stabilization afforded by these cross-links is approximately 1 kcal/mol, similar to that reported for peptides cross-linked between the i and i + 4 residues, and derives exclusively from a loss of entropy of the unfolded state. The presence of the alpha-helical structure appears to correlate well with biological activity. This study provides initial insight into the bioactive structure of this domain of apo E and suggests strategies as to how peptides can be conformationally constrained to enhance their stability and biological function.

Left ventricular mass and geometry before and after etiologic treatment in renovascular hypertension, aldosterone-producing adenoma, and pheochromocytoma

To study left ventricular (LV) geometry in secondary hypertension and its evolution following etiologic treatment, echocardiography was performed in a total of 73 patients: 40 patients with renovascular hypertension (RVH), 21 with aldosterone-producing adenoma (APA), and 12 with pheochromocytoma (PH). Repeat echocardiography was possible in 43 of these patients, 3-24 months following curative renal revascularization or adrenal surgery. Age, sex ratio, and initial drug treatment score were comparable in the three etiologic categories, but 24-h ambulatory blood pressure and LV mass index were significantly higher in APA and RVH than in PH. End-diastolic LV volume was significantly smaller in PH than in APA and RVH. After treatment, the greatest reduction in LV mass occurred in APA (-18%, P < .05) and the lowest in PH (-5%, NS). Both patients with APA and those with PH exhibited a significant decrease in LV wall thickness, whereas LV diameter tended to decrease in APA patients and to increase in PH patients. No significant cardiac changes occurred in RVH patients after treatment. Although LV mass index and ambulatory blood pressure were correlated both before and after treatment, LV mass index changes did not correlate with changes in ambulatory blood pressure or with the known duration of hypertension. Systolic function was normal before and following etiologic treatment in the three categories. These findings suggest that, in addition to blood pressure, volume and/or humoral factors influence the pathogenesis of left ventricular hypertrophy and its reversibility.

Acute effects of a pseudo-tetrapeptide as renin inhibitor on blood pressure and renin-angiotensin system of sodium-repleted and sodium-depleted hypertensive patients

The blood pressure and renin-angiotensin system effects of the new renin inhibitor, SR 43845 ([N-(pyridyl-3-propionyl)-phenylalanyl- histidyl-(3S,4S) ACHPA-isoleucylamino]-2-methyl-2-dihydroxy-1,3-propane), were studied in 12 hypertensive patients on a normal sodium intake who received a 30-min infusion of intravenous SR 43845 at one of 3 doses: 30, 100 or 300 micrograms/kg (4 patients per group). Eight further patients were infused with the 300 micrograms/kg dose 24 h after 80 mg furosemide orally. In sodium-repleted patients, the 30, 100 and 300 micrograms/kg doses induced a rapid fall in diastolic blood pressure (DBP) which culminated at 4.5, 7.5 and 3.9 mmHg, respectively. Salt depletion increased the renin inhibitor-induced fall in DBP to 10.8 mmHg. DBP was back to baseline at 60 min after starting the lowest dose and 180 min after starting the highest dose. Heart rate did not change. In four of the sodium-depleted patients, 50 mg captopril was given orally at T = 180 min, when blood pressure had returned to baseline. The decrease in BP (8.8 mmHg) was similar to that initially obtained with the renin inhibitor (10.1 mmHg). Plasma angiotensin (Ang) I was dose-dependently reduced by 62, 93 and 92% of baseline values 10 min after the start of the infusion in sodium-repleted patients, and by 90% in sodium-depleted patients; it returned to baseline in both situations between 180 and 360 min. Plasma Ang II levels changed in parallel with those of plasma Ang I.(ABSTRACT TRUNCATED AT 250 WORDS)

[Left ventricular involvement in Conn adenoma, renovascular hypertension and pheochromocytoma before and after etiological treatment]

AIM OF THE STUDY

Assessment of left ventricular (LV) structural modifications following etiologic treatment of secondary hypertension, in a group of 43 patients.

PATIENTS AND METHODS

M-Mode echocardiograms were independently analysed by 2 trained investigators before and 7.4 months (RV), 11 patients with COnn's adenoma (C) and 9 patients with phaeochromocytoma (PH).

RESULTS

Age, sex ratio, antihypertensive treatment, and duration of hypertension before treatment were comparable among the 3 groups. Blood pressure was higher in C and RV than in PH for casual (C: 190/116; RV: 193/109; PH: 146/91; p < 0.01/0.05) as well as ambulatory blood pressure (C: 140/93; RV 153/89; PH: 126/80; p < 0.01/0.05). Before etiologic treatment, systolic function was normal in the 3 groups whereas LV mass index differed between the 3 groups (C: 147; RV: 118; PH: 85 g/m2). LV end diastolic diameter index was smaller in PH (26.4 mm/m2) than in C (29.1) and RV (28.8). After treatment, there was a significant reduction on office (C: -43/-20; RV: -39/-19; PH: -20/-12 mmHg) and ambulatory (C: -6.6/-5.6; R: -20/-9.9; PH: -4.7/- 4.5) blood pressure. Systolic function was not altered. LV mass index was significantly reduced in C and RV but not in PH (C: -18%; RV: -7%; PH: -5%). Changes in LV end diastolic diameter index were not significant (C: -2%; RV: 0%; PH: + 6%). There was no correlation between LV mass index changes and blood pressure differences.

CONCLUSION

Etiologic treatment leads to significant regression of LV hypertrophy in patient with renovascular hypertension or Conn's adenoma, at least partly independently of blood pressure change. Humoral and volume factors may play a role in LV regression.

Identification of Leishmania donovani isolates from different kala-azar foci in China by kDNA hybridization

kDNA sequence homology of Leishmania donovani isolates from three types of kala-azar foci in China were analyzed by using dot and Southern hybridization with biotin- and 32P-labelled probes. The results revealed kDNA sequence heterogeneity among Leishmania donovani isolates from the three kala-azar foci: sequence homology between isolates of hill and desert foci was higher than that between hill and plain foci isolates. The kDNA hybridization technique was also found to be specific and sensitive for direct identification of Leishmania in animal tissues. In a preliminary survey, kDNA hybridization of cutaneous tissue blots of 71 dogs from endemic regions showed a positive rate of 40.8%, and the rate of double positive cases (touch blot hybridization and bone marrow smear) reached 91.3%. The direct identification of Leishmania in tissues by kDNA hybridization seems to be a useful and convenient method for epidemiological study and clinical diagnosis, especially for species/strain characterization.

The anatomical evidence of recurrent axonal collaterals of the thalamus projecting neurons of the rostral pole of the trigeminal sensory nuclear complex in the rat

Thalamus projecting neurons and their recurrent axonal collaterals were observed in the dorsomedial part of the trigeminal principal sensory nucleus (Vpdm) and the caudolateral part of supratrigeminal nucleus (Vsup CL) after injection of horseradish peroxidase (HRP) into the contralateral ventrobasal complex of the thalamus (VBm) by using the HRP retrogradely tracing-Golgi-like staining method. About 7% (8/120) parent axons of the labeled cells gave rise to recurrent axon collaterals. However, no retrogradely labeled cells were observed in the VBm after injection of HRP into the Vpdm and Vsup CL. In an electron microscopic study, the terminals of recurrent axon collaterals made synapses with the dendrites of the thalamus projecting neurons or non-labeled neurons in the neuropil of the Vpdm and Vsup CL. It is suggested that the recurrent axon collaterals might play a role of negative feedback in transmission of the proprioceptive message from the jaw-closing muscle spindles to the thalamus.

[Nucleus fastigius-rostral ventrolateral medulla system is involved in vestibular depressor and bradycardia responses]

In urethane-anesthetized, tubocurarine-immobilized and artificially ventilated rats, microinjection of L-glutamate (Glu) into the nucleus fastigius or nucleus vestibular superior caused a depressor and bradycardia response. Both the depressor and bradycardia responses of the nucleus fastigius and nucleus vestibularis superior were blocked by preinjection of bicuculline (a GABAergic receptor blocker) into the rostral ventrolateral medulla. And the cardiovascular response-induced by excitation of the nucleus vestibularis superior could also be blocked by procaine-injection into the nucleus fastigius. These results indicate that the vestibular depressor and bradycardia response was induced via the nucleus fastigius rostral ventrolateral medulla system. Intravenous injection of methyl atropine also markedly attenuated the cardiovascular response of the nucleus fastigius, indicating that the vagus nerve is also involved in the depressor and bradycardia response of vestibulo-fastigial excitation.