Studies on the distribution of vasopressin-immunoreactive neuronal perikarya and their fibers in the hypothalamus of Tupaia belangeri

The distribution of vasopressin (VP)-immunoreactive neuronal perikarya and its fibers had been studied in the hypothalamus of Tupaia belangeri using the avidin-biotin complex (ABC) immunocytochemical technique. VP-immunoreactive neurons were found in the hypothalamic paraventricular nucleus (PVN), supraoptic nucleus (SON), accessory supraoptic nucleus (ASN), hypothalamic lateral nucleus (HLN), perifornical nucleus (PFN) and ansa peduncularis (AP) but not in the suprachiasmatic nucleus (SCN). VP neurons of the rostral PVN could be divided into three subnuclei and the caudal PVN could also be divided although not so distinctly into four subnuclei. The VP-immunoreactive neuronal perikarya of SON were divided into three parts, i.e., medioventral, mediodorsal and laterodorsal. Three types of VP neuronal perikarya, i.e., large, medium and small cells, existed in PVN and SON. Between PVN and SON, there were a large number of VP immunopositive nerve fibers. In addition, there were numerous immunopositive fibers projecting into the infundibulum and the neurohypophysis. VP-immunoreactive-positive products localized in the large granular vesicles and on the rough-surfaced endoplasmic reticulum could be seen under electron microscope.

Evolution and phylogeny of Wolbachia: reproductive parasites of arthropods

Wolbachia are cytoplasmically inherited bacteria found in reproductive tissues of many arthropod species. These bacteria are associated with reproductive alterations in their hosts, including parthenogenesis, reproductive incompatibility and feminization. A fine-scale phylogenetic analysis was done using DNA sequences from ftsZ, a rapidly evolving bacterial cell-cycle gene. ftsZ sequences were determined for 38 different Wolbachia strains from 31 different species of insects and one isopod. The following results were found: (i) there are two major division of Wolbachia (A and B) which diverged 58-67 millions years before present based upon synonymous substitution rates; (ii) a general concordance is found between the ftsZ and 16S rDNA phylogenies, indicating that these represent bacterial strain (rather than simply gene) phylogenies; however, a possible example of recombination between A and B division bacteria may have occurred in the feminizing Wolbachia present in an isopod; (iii) extensive horizontal transmission of Wolbachia has occurred between insect taxa, including different insect orders; one strain in particular (designated Adm) shows extensive recent horizontal transmission; (iv) there is an association between the Wolbachia found in a parasitic wasp (Nasonia) and its fly host (Protocalliphora), suggesting exchange of bacteria between these species; (v) parthenogenesis induction has evolved several times among the Wolbachia; and (vi) some insects harbour infections with more than one Wolbachia strain, even within individual insects.

Insulin-like growth factor-I (IGF-I) and glutamine improve structure and function in the small bowel allograft

IGF-I, a mitogenic polypeptide hormone, and glutamine (GLN), the preferred enterocyte fuel, singularly improve growth and structure of the small bowel isograft; however, their combined effects on intestinal allografts are unknown. This study examined the effects of IGF-I and GLN, singularly and in combination, on the structure and function of the intestinal allograft. Fifty-nine adult rats underwent resection of the distal 60% of small bowel and received either a 40-cm isograft or an allograft. Either IGF-I (2.4 mg/kg/day) or its vehicle was infused continuously by subcutaneous minipumps. An isocaloric polymeric diet with either 2% GLN or isonitrogenously balanced 2% nonessential amino acids was given continuously by gastrostomy for 10 days. Five groups were studied: isograft (ISO) alone, allograft (ALLO) alone, ALLO and GLN, ALLO and IGF-I, and ALLO and IGF-I with GLN. All recipients received Cyclosporine A (15 mg/kg, im) daily. Mucosal villus height, surface area, crypt depth, IgA, IgG, IgM, and intercellular adhesion molecule-1 (ICAM-1) plasma cells in intestinal tissue, glucose and water absorption of intestinal graft, bacterial translocation (BT) to mesenteric lymph nodes, and body weight were determined. IGF-I increased villus height, surface area (P < 0.001), crypt depth (P < 0.01), and glucose absorption (P < 0.05) compared to the ISO and ALLO groups. GLN increased only crypt depth when compared to the ALLO group (P < 0.01). Both IGF-I and GLN independently decreased BT to MLN (P < 0.05) and, in combination, enhanced water absorption (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Relation between cyclic GMP generation and cerebrovascular reactivity: modulation by NPY and alpha-trinositol

It is considered that cyclic guanosine monophosphate (cGMP) plays a pivotal role in mediating the relaxation of vascular and nonvascular smooth muscles. cGMP steady state levels are regulated by guanylyl cyclase, cGMP phosphodiesterases and its flux from cells. The present study examines the possible relation between cerebrovascular vasodilator agents and generation of cGMP in guinea pig cerebral vessels. Acetylcholine, substance P, nitroglycerine and sodium nitroprusside significantly increased the generation of cGMP. The application of acetylcholine, substance P, nitroglycerine and sodium nitroprusside elicited concentration-dependent relaxation of basilar artery segments. Neuropeptide Y increased the generation of cGMP by 2%-46% of control levels (at 10(-7)-10(-6)M of neuropeptide Y; *P < 0.05). In addition, neuropeptide Y (10(-6)M) induced a transient relaxation of the precontracted guinea pig basilar arteries with endothelium. This transient relaxation was blocked by nitro-L-arginine (10(-4)M). alpha-Trinositol does not alter the formation of cGMP nor the neuropeptide Y-induced relaxation. In the presence of alpha-trinositol neuropeptide Y (10(-7)-10(-6)M) did not significantly elevate the production of cGMP as compared with controls. The rise in cGMP induced by acetylcholine, substance P and nitroglycerine was slightly increased by the addition of neuropeptide Y (3 x 10(-7) M). Acetylcholine and substance P induced an endothelium-dependent relaxation of the precontracted guinea pig basilar arteries, while sodium nitroprusside and nitroglycerine induced an endothelium-independent relaxation. Acetylcholine, substance P and nitroglycerine induced concentration-dependent relaxations of basilar artery, respectively. The relaxation elicited by acetylcholine or substance P, but not nitroglycerine, was markedly attenuated by neuropeptide Y (3 x 10(-7) M).(ABSTRACT TRUNCATED AT 250 WORDS)

Immunohistochemical dynamics of leukotoxin (9,10-epoxy-12-octadecenoic acid) in lungs of rats

This paper investigates the immunohistochemical dynamics of leukotoxin (9,10-epoxy-12-octadecenoic acid, LTx) in the lungs of rats exposed to hyperoxia with or without paraquat. The rats were treated with 100% oxygen or ambient air for 24, 48, 72 and 96 h in the presence or absence of a low or high dose paraquat (1,1'-dimethyl-4,4'-bipyridinium, PQ) injection. Immunostaining for LTx demonstrated positive reactions in the neutrophils that showed a progressive increase in intensity of staining with time in all groups exposed to 100% oxygen and in the group with high dose PQ, but the positive findings were weak in the group injected with low dose PQ only. We found the positive immunostaining reaction not only in neutrophils but also in alveolar macrophages. This indicates that LTx is produced by alveolar macrophages as well as by neutrophils depending on the treatment period under hyperoxic conditions, suggesting that LTx is an important chemical mediator in pulmonary diseases.

Inactivation of the myogenic bHLH gene MRF4 results in up-regulation of myogenin and rib anomalies

The myogenic basic helix-loop-helix (bHLH) proteins MyoD, myf5, myogenin, and MRF4 can initiate myogenesis when expressed in nonmuscle cells. During embryogenesis, each of the myogenic bHLH genes is expressed in a unique temporospatial pattern within the skeletal muscle lineage, suggesting that they play distinct roles in muscle development. Gene targeting has shown that MyoD and myf5 play partially redundant roles in the genesis of myoblasts, whereas myogenin is required for terminal differentiation. MRF4 is expressed transiently in the somite myotome during embryogenesis and then becomes up-regulated during late fetal development to eventually become the predominant myogenic bHLH factor expressed in adult skeletal muscle. On the basis of its expression pattern, it has been proposed that MRF4 may regulate skeletal muscle maturation and aspects of adult myogenesis. To determine the function of MRF4, we generated mice carrying a homozygous germ-line mutation in the MRF4 gene. These mice showed only a subtle reduction in expression of a subset of muscle-specific genes but showed a dramatic increase in expression of myogenin, suggesting that it may compensate for the absence of MRF4 and demonstrating that MRF4 is required for the down-regulation of myogenin expression that normally occurs in postnatal skeletal muscle. Paradoxically, MRF4-null mice exhibited multiple rib anomalies, including extensive bifurcations, fusions, and supernumerary processes. These results demonstrate an unanticipated regulatory relationship between myogenin and MRF4 and suggest that MRF4 influences rib outgrowth through an indirect mechanism.

The effect of posterior element resection on the stress distribution in the lumbar spine

A three-dimensional finite element model of the lumbar motion segment was used to predict the stress distribution in lumbar spine with posterior element resection. It was shown that the stress level in all parts of the lumbar spine was elevated although the stress distribution remained unchanged. The authors concluded that the posterior element resection in lumbar surgery should be avoided as much as possible.

Wild-type human p53 and a temperature-sensitive mutant induce Fas/APO-1 expression

Fas/APO-1 is a cell surface protein known to trigger apoptosis upon specific antibody engagement. Because wild-type p53 can activate transcription as well as induce apoptosis, we queried whether p53 might upregulate Fas/APO-1. To explore this possibility, we examined human p53-null (H358 non-small-cell lung adenocarcinoma and K562 erythroleukemia) and wild-type p53-containing (H460 non-small-cell lung adenocarcinoma) cell lines. When H358 or H460 cells were transduced with a replication-deficient adenovirus expression construct containing the human wild-type p53 gene but not with vector alone, a marked upregulation (approximately a three-to fourfold increase) of cell surface Fas/APO-1 was observed by flow cytometry. Similarly, K562, cells stably transfected with a plasmid vector containing the temperature-sensitive human p53 mutant Ala-143 demonstrated a four- to sixfold upregulation of Fas/APO-1 by flow-cytometric analysis at the permissive temperature of 32.5 degrees C. Temperature-sensitive upregulation of Fas/APO-1 in K562 Ala-143 cells was verified by immunoprecipitation and demonstrated to result from enhanced mRNA production by nuclear run-on and Northern (RNA) analyses. Stably transfected K562 cells expressing temperature-insensitive, transcriptionally inactive p53 mutants (His-175, Trp-248, His-273, or Gly-281) failed to upregulate Fas/APO-1 at either 32.5 degrees or 37.5 degrees C. The temperature-sensitive transcription of Fas/APO-1 occurred in the presence of cycloheximide, indicating that de novo protein synthesis was not required and suggested a direct involvement of p53. Collectively, these observations argue that Fas/APO-1 is a target gene for transcriptional activation by p53.

Synthesis of novel imidazobenzodiazepines as probes of the pharmacophore for "diazepam-insensitive" GABAA receptors

The syntheses of a series of novel imidazobenzodiazepines and their affinities for diazepam sensitive (DS) and diazepam insensitive (DI) GABAA receptors are described. Imidazobenzodiazepines belong to one of the very few chemical families which exhibit high to moderate potency for DI GABAA receptors. Although imidazobenzodiazepines such as Ro 15-4513, 20, are the most potent DI GABAA receptor ligands described to date, their selectivity for DI versus DS GABAA receptors is only marginal. Previous structure-activity relationship (SAR) studies of imidazobenzodiazepines have indicated that the 3- and 8-positions are critical for high-affinity binding to DI GABAA receptors (J. Med. Chem. 1993, 36, 479-490. J. Med. Chem. 1993, 36, 1001-1006. J. Med. Chem. 1993, 36, 1820-1830). In order to determine why the ester function is critical to high affinity at the DI site, we have synthesized several derivatives which have substituents other than an ester at the C(3) position including 3-alkyl-, 3-alkylketo-, 3-alkyl ether, and 3-dialkylamino-substituted imidazobenzodiazepines. The SAR analysis of these compounds when combined with that of several pyrazoloquinolinones indicates that interactions at H1 and L1 as well as interactions at H2 anti to the imidazole N(2) and at a lipophilic pocket (labeled LDi) about the 3-position are required in order for imidazobenzodiazepines to exhibit selectivity and high affinity for DI GABAA receptors. Furthermore, the imidazobenzodiazepines substituted with an electron-donating group (alkoxy function) at position 8 revealed that the change of the substituent at C(8) from an electron-withdrawing to a donating function did not substantially alter either ligand affinity or selectivity for DI GABAA receptors. Thus, a pharmacophore is proposed for DI GABAA receptor ligands, which is characterized by the requirement of a lipophilic pocket LDi about the C(3) position of imidazobenzodiazepines. Using this model, two pyrazoloquinolinone derivatives were designed and synthesized. Their affinities and selectivities for DI GABAA receptors are consistent with those predicted by the DI GABAA receptor pharmacophore. In addition, examination of the in vitro binding data of 3-alkyl ether analogs confirms that the anti conformation of the ester group at the C(3) position of imidazobenzodiazepines (Ro15-4513, 20 series) is preferred at both DI and DS GABAA receptors. This constitutes the first evidence (other than molecular modeling) to support the auxillary involvement of H2 at the DI site and is important with regard to the synthesis of other DI GABAA receptor selective ligands in the future.(ABSTRACT TRUNCATED AT 400 WORDS)

Identification and characterization of the human myeloperoxidase promoter

Myeloperoxidase (MPO) is a microbicidal protein present in the primary granules of myeloid cells. Transcription of the MPO gene is turned on only during the late myeloblast and promyelocyte stages of myeloid maturation. Identification of cis-regulatory elements and transcription factors which regulate the MPO gene should, therefore, shed light on myeloid maturation. We report transfection and in vitro transcription experiments which demonstrate promoter activity in the proximal 5'-flanking region of the human MPO gene. Using a chloramphenicol acetyl transferase (CAT) reporter vector system, and segments of the 5'-flanking MPO DNA, we constructed a series of MPO promoter-CAT expression vectors. By electroporation and lipofectin-mediated transient transfection assays, as well as by in vitro transcription studies, a 594-bp MPO DNA sequence (bp -583 to +11) showed promoter activity in a variety of MPO-expressing and non-MPO-expressing cell lines. Compared with the SV40 early promoter, the MPO promoter had greater relative activity in MPO-expressing than in non-MPO-expressing cell lines, suggesting slight tissue specificity. However, a CAT reporter plasmid containing 1099-bp of 5'-flanking MPO DNA showed greater specificity for MPO expressing cell lines. Analysis of a group of promoter deletion mutants showed that the minimal promoter was contained in a DNA fragment extending from bp-128 to +11. The remainder of the promoter region contained several segments which appeared to enhance the activity of the minimal promoter. One such enhancer sequence was homologous to an enhancer previously described in the human elastase promoter. Activity of the 594-bp MPO promoter in HL-60 was reduced by only approximately 30% following treatment of the cells with chemical inducers of maturation, but the 1099-bp MPO promoter showed 60% reduction in activity after DMSO treatment. A previously described enhancer region in intron 9 of the MPO gene had little or no effect on activity of the 594-bp MPO promoter. The availability of the MPO promoter will facilitate determination of other factors involved in the regulation of this myeloid-specific gene.

Epidemiological and aetiological studies on hair casts

Hair casts (HC) appear to have become more common in young adults. An investigation on the incidence of HC was made in the Chengdu district of China. Of 3548 individuals surveyed, 30.24% suffered from HC. HC were restricted to females, among whom the incidence was 61.6%. HC is thus a very common finding. Long-term and frequent traction imposed on hair with excessive force appears to be the major cause of HC. This was confirmed from braiding studies which consisted of traction by tightly drawn braids on healthy subjects, together with histopathology of the underlying skin and statistical data on the frequency of HC.

A quantitative analysis of alternated line scanning in k space and its application in MRI of regional tissue perfusion by arterial spin labeling

A quantitative analysis of the alternated-line-scanning method is performed for k-space data acquisition in MRI. Application of the method in MRI of regional tissue perfusion by arterial spin labeling is demonstrated. It is also shown that, by using the alternated-line-scanning method, the degree of arterial spin labeling alpha can be determined in a single scan.

A new animal model of coronary thrombosis and effects of antithrombotic agents

The model was established in male rabbits with experimental atherosclerosis, which was induced by diet cholesterol (0.5 g per day for 8 weeks), by means of intravenous injection of one unit of pituitrin (P.P.). To evaluate the effects of aspirin, heparin and viper venom (VV) on this model, 26 male rabbits were divided randomly into four groups: group A (GA) as control, group B (GB) treated with heparin (10mg, i.v.), group C (GC) with VV (0.08 arginine esterase activity units), group D (GD) with both heparin and VV. Aspirin (30 mg) was given orally before experiment. The results showed that the rate of coronary thrombosis was 11.26% in GA, 8.10% in GB, 9.17% in GC, and 7.56% in GD respectively. The difference between each of three treated groups and the control one was significant (P < 0.005, 0.05, 0.001, respectively). Such a difference can also be found between GA and that without oral aspirin (11.26% vs 16.39%, P < 0.001). The beneficial effects of heparin and VV may be due to their inhibitory effects on different steps of thrombosis, i.e., heparin can prolong the coagulation time, and VV can inhibit platelet aggregation and decrease the concentration of plasma fibrinogen. It is concluded that heparin, viper venom, and especially their combination would be useful in the treatment of human acute coronary syndromes.

[Longitudinal studies of developmental status in term-born infants with hyperbilirubinemia]

Thirty-six infants born at term who developed hyperbilirubinemia were assessed for developmental status at 2, 4, 6, 9 and 12 months of age according to a mental and psychomotor scale for 0-4 year old. The development quotient (DQ) of infants with hyperbilirubinemia were lower than controls, and the reduction was significant at 2 months of age (P = 0.03). When single component of DQ was compared, it was shown that the DQ score for social behavior was significantly lower in patients at 2 months of age than in control (P = 0.007), and except for motor, other four single DQ scores were lower in patients than in control and the reduction was significant in the DQ scores for adaptability and social behavior (P = 0.05, 0.032, respectively). Furthermore, no significant correlation was found between DQ and serum peak bilirubin value or duration of hyperbilirubinemia. The results indicate that hyperbilirubinemia may have a long term impact on mental development of infants. It is necessary to monitor all infants with hyperbilirubinemia, including full term infants with no severe complication.

Structure of HIV-1 reverse transcriptase in a complex with the non-nucleoside inhibitor alpha-APA R 95845 at 2.8 A resolution

BACKGROUND

HIV-1 reverse transcriptase (RT) is a multifunctional enzyme that copies the RNA genome of HIV-1 into DNA. It is a heterodimer composed of a 66 kDa (p66) and a 51 kDa (p51) subunit. HIV-1 RT is a crucial target for structure-based drug design, and potent inhibitors have been identified, whose efficacy, however, is limited by drug resistance.

RESULTS

The crystal structure of HIV-1 RT in complex with the non-nucleoside inhibitor alpha-anilinophenyl-acetamide (alpha-APA) R95845 has been determined at 2.8 A resolution. The inhibitor binds in a hydrophobic pocket near the polymerase active site. The pocket contains five aromatic amino acid residues and the interactions of the side chains of these residues with the aromatic rings of non-nucleoside inhibitors appear to be important for inhibitor binding. Most of the amino acid residues where mutations have been correlated with high levels of resistance to non-nucleoside inhibitors of HIV-1 RT are located close to alpha-APA. The overall fold of HIV-1 RT in complex with alpha-APA is similar to that found when in complex with nevirapine, another non-nucleoside inhibitor, but there are significant conformational changes relative to an HIV-1 RT/DNA/Fab complex.

CONCLUSIONS

The non-nucleoside inhibitor-binding pocket has a flexible structure whose mobility may be required for effective polymerization, and may be part of a hinge that permits relative movements of two subdomains of the p66 subunit denoted the 'palm' and 'thumb'. An understanding of the structure of the inhibitor-binding pocket, of the interactions between HIV-1 RT and alpha-APA, and of the locations of mutations that confer resistance to inhibitors provides a basis for structure-based design of chemotherapeutic agents for the treatment of AIDS.

[The relationship of intraacinar pulmonary arterial structural remodelling with pulmonary hypertension]

Pulmonary hypertension (PHT) was induced in rats by a single subcutaneous injection of monocrotaline (MCT). Light and electron microscopy, immunohistochemistry and morphometry were applied to investigate the different pathological changes of the intraacinar pulmonary arteries (IAPA) and their relationship with PHT. The results showed that pulmonary function was related to the morphological structure and indicated that the remodelling in the IAPA structure was the pathological basis of PHT. The results further suggested that the proliferation and myoid differentiation of the pericyte play an important role in the muscularization of the nonmuscular pulmonary artery in IAPA.

Influence of tissue freezing on the binding of 125I-sarcosine1, isoleucine8 angiotensin II to angiotensin II receptor subtypes in the rat

Evaluation of angiotensin II (AII) receptor binding often necessitates freezing of the tissue of interest prior to assay of radioligand binding. This study evaluated the effects of freezing of various rat tissues at different rates on 125I-sarcosine1, isoleucine8 angiotensin II (125I-SI AII) binding to AII receptor subtypes. Slow freezing in a -20 degrees C compartment significantly reduced 125I-SI AII binding to AT1 receptors in the adrenal (51%), epididymis (34%), and liver (22%). Binding of 12tI-SI AII to the AT1 receptor in the brain was not significantly reduced. In the adrenal, both the Bmax and affinity of AT1 receptors were decreased by freezing. But in the epididymis, only the affinity of AT1 receptors was decreased. Binding of 125I-SI AII to AT2 receptors in the adrenal, epididymis, and brain was also not significantly reduced by freezing. Further evaluation of the mechanism of the reduction in 125I-SI AII binding to AT1 receptors in the adrenal indicated that both the receptor density and affinity for 125I-SI AII were decreased by freezing. Rapid freezing in a dry-ice bath caused even greater reductions in 125I-SI AII binding to AT1 receptors in the adrenal. Snap freezing in liquid nitrogen decreased 125I-SI AII binding in adrenals to a similar extent as did slow freezing. These results suggest that studies of AII receptors subtypes that involve freezing of the tissues underestimate the density and affinity of the AT1 receptor subtype.

Pharmacological characterization of angiotensin II AT(2) receptor subtype heterogeneity in the rat adrenal cortex and medulla

Adrenal angiotensin II (AII) receptors have been pharmacologically and structurally divided into two main subtypes, AT(1) and AT(2). Radioligand receptor binding assays with(125)I-sarcosine(1), isoleucine(8) angiotensin II ((125)I-SI AII) in the presence of losartan, an AT(1) selective ligand, and PD123177 an AT(2) selective ligand, indicated that the AT(1) subtype was predominant in membrane homogenates of the rat adrenal cortex (AT(1) Bmax=649 ± 62 fmol/mg protein; AT(2) Bmax=237 ± 29 fmol/mg protein). In membrane homogenates of the adrenal medulla, the AT(2) subtype was predominant (AT(1) Bmax=55 ± 5 fmol/mg protein; AT(2) Bmax=109 ± 29 fmol/mg protein). Overall 58% of the(125)I-SI AII binding in the rat adrenal was to the AT(1) subtypes, and 42% was to the AT(2) subtypes. The outer cortex contained 59% of the AH receptor binding sites in the adrenal, while the medulla accounted for the remaining 41%. The affinity of the AT(1) binding sites in membrane homogenates of the cortex and medulla (K( D )=672 ± 123 pM and 573 ± 85 pM, respectively) was not significantly different. The affinity for(125)I-SH AII of AT(2) binding sites in membrane homogenates was higher than that of AT, binding sites. The affinity for(125)I-SI All of AT(2) binding sites in membrane homogenates of the outer cortex (K( D )=265 ± 35 pM) was significantly less than that in the medulla (K( D )=133 ± 11 pM).In vitro receptor autoradiography also demonstrated that the AT(2) subtype in frozen sections of the cortex had a lower affinity (K( D )=1512 ± 191 pM) than that in the medulla (K( D )=867 ± 72 pM). The heterogeneous affinity of adrenal AT(2) binding sites may indicate existence of multiple AT(2) receptor subtypes in the rat adrenal.

Cruciate paralysis caused by injury of the upper cervical spine

Cruciate paralysis is an uncommon injury to the cervicomedullary junction. Five patients with injuries of the upper cervical spine and the clinical manifestation of cruciate paralysis are presented. This injury pattern is characterized by bilateral upper extremity paralysis, with minimal or no lower extremity involvement. The neuroanatomic basis and the diagnosis of this clinical entity are discussed, and the related reports in the literature are reviewed.

Control of lamprey locomotor neurons by colocalized monoamine transmitters

Neurons in the central nervous system (CNS) often store more than one neurotransmitter, but as yet the functional significance of this type of coexistence is poorly understood. 5-Hydroxytryptamine (5-HT) modulates calcium-dependent K+ channels (KCa) responsible for the postspike afterhyperpolarization in different regions of the CNS. In lamprey, 5-HT neurons control apamine-sensitive KCa channels in spinal locomotor network interneurons, thereby in addition regulating the duration of locomotor bursts. We report here that these spinal 5-HT neurons also contain dopamine. Like 5-HT, dopamine causes a reduction of the afterhyperpolarization, but in this case it is due to a reduction of calcium entry during the action potential, which results in a reduced activation of KCa. 5-HT and dopamine are both released from these midline neurons, and both reduce the afterhyperpolarization through two distinctly different, but complementary cellular mechanisms. The net effect of dopamine (10-100 microM) on the locomotor network is similar to that of 5-HT, and the effects of dopamine and 5-HT are additive at the network level.

Insulin-like growth factor-I improves mucosal structure and function in transplanted rat small intestine

The transplanted small intestine develops significant mucosal atrophy, impaired nutrient and water absorption, and increased bacterial translocation to mesenteric lymph nodes in rats maintained on elemental diets or total parenteral nutrition. This study determined the effects of administration of an peptide growth factor (insulin-like growth factor-I[IGF-I]) on the mucosal structure and barrier function of rat small bowel isografts. Thirty-six adult Lewis rats underwent either resection of the distal 60% of the small bowel and proximal colon followed by a 40-cm orthotopic jejunal isograft or proximal small bowel transection and distal small bowel resection to leave an analogous length of small intestine in control animals. All rats received an isocaloric, isonitrogenous, polymeric diet (200 kcal/kg/day, 2 gN/kg/day) by gastrostomy and were infused with either IGF-I (2.4 mg/kg/day) or vehicle by osmotic pumps subcutaneously. After 10 days of treatment, jejunal crypt cell production, mucosal morphometric indices, glucose and water absorption, body weight, and bacterial translocation to mesenteric lymph nodes (MLN) were measured. Jejunal mRNA content for IGF-I, IGF-I receptor, and IGF-binding proteins 3 and 4 (IGFBP-3,4) were determined by Northern blotting. Crypt cell production, villus height, crypt depth, and villus surface area were significantly increased in control and transplanted jejunum of rats infused with IGF-I when compared to animals given vehicle alone. Additionally, jejunal glucose absorption and water absorption were significantly improved in both IGF-I groups when compared with their respective vehicle controls. IGF-I infusion increased body weight in transplanted and control animals and markedly reduced bacterial translocation to MLN after small bowel transplantation. Jejunal levels of IGF-I mRNA were significantly increased in transplanted animals when compared to transected controls. IGF-I treatment significantly increased IGFBP-3 tissue mRNA levels in both transected and transplanted animals. These results demonstrate that IGF-I administration, after small bowel transplantation, improves mucosal structure and absorptive function and reduces bacterial translocation to MLN. IGF-I may have important effects in transplanted small bowel both as an endogenous and administered growth factor.

NMR measurement of perfusion using arterial spin labeling without saturation of macromolecular spins

When measuring perfusion by arterial spin labeling, saturation of tissue macromolecular spins during arterial spin labeling greatly decreases tissue water magnetization, reducing the sensitivity of the technique. In this work, a theory has been developed for perfusion measurement by arterial spin labeling without saturation of macromolecular spins. A two-coil system was used to achieve arterial spin labeling without saturation of brain tissue macromolecular spins for NMR measurement of rat cerebral perfusion. The effects of cross-relaxation on the measurement of perfusion have been studied in the absence of macromolecular spin saturation, and it is demonstrated that at 4.7 Tesla, perfusion is underestimated by approximately 17% when the effect of cross-relaxation is neglected in the calculation of perfusion. However, assuming water to be a freely diffusable tracer, the effect of cross-relaxation is predicted to be flow independent, and it can, thus, be accounted for in the calculation of perfusion. The theory and experiments are presented to estimate tissue perfusion, magnetization transfer rate constants, and spin-lattice relaxation times of water and macromolecular spins in rat brain.

Glutathione disulphide as a marker of reperfusion injury in ischaemic skin flaps

Estimation of the oxidised form of glutathione (GSSG) in an ischaemic/reperfused organ is frequently employed as an indicator of oxidative stress created by the production of oxygen free radicals during the reperfusion period. The time course of oxidative stress and tissue damage in 19 ischaemic/reperfused guinea-pig island skin flaps was evaluated. No-flow ischaemia was induced in the flaps for 6 h in 7 animals, and for 8 h in 9 animals (a further 3 animals served as controls without ischaemia). Arterial and venous blood samples were obtained directly from the flap pedicle at baseline, 10, 30, and 60 min following reperfusion. Results suggest that a second focus of oxidative injury, possibly mediated by activated neutrophils, contributes to the overall process of reperfusion injury. Plasma levels of GSSG allow for a more sensitive quantification of oxidant stress within reperfused ischaemic flaps, and may serve as a useful tool in skin flap research.

Ultrastructural changes following overhydration with irrigating fluids

We studied ultrastructural alterations caused by intravenous infusion of 150 ml/kg of irrigating fluid containing mannitol and/or sorbitol in 15 rabbits. The osmolality of the solutions varied between 165 and 350 mosmol/kg. Specimens for electron microscopic examination were obtained from the kidney, brain and lung. Regardless of the choice of solute, the hypo-osmotic solutions caused damage to kidney and brain tissue by inducing marked interstitial and cellular oedema. No such changes were observed after administration of isosmotic irrigating fluid. We conclude that ultrastructural changes following overhydration with irrigating fluid vary with the osmolality of the solution but not with the choice of solute. Moreover, the consistent absence of tissue damage in the lungs suggests that the lung is not a primary target organ for the "TUR syndrome".

EGF-mediated phosphorylation of extracellular signal-regulated kinases in osteoblastic cells

Epidermal growth factor (EGF) induces a rapid increase in the phosphorylation of extracellular signal-regulated kinases (ERKs) in the human osteosarcoma osteoblastic cell line G292 and in primary cultures of rat osteoblastic cells. This phosphorylation is transient and time-dependent. Maximal stimulation is attained within 1 min in G292 and within 5 min in rat osteoblastic cells. Enzymatic activity in G292 cells is also induced rapidly after EGF stimulation. Western blot analysis revealed that enhancement of the phosphorylation of ERKs in the EGF-stimulated cells is not due to an increase in ERK protein, since EGF-treatment does not lead to an increase in the absolute amount of ERKs present even after 2 days of stimulation. The pattern of expression of the ERKs observed in the two cell types differs in the apparent molecular weights observed. The most slowly migrating immunoreactive protein (approximately 45 kDa) in normal rat osteoblastic cells is ERK1, identified by an ERK1-selective antiserum. The same antiserum reacts only weakly with one of the ERK proteins (44 kDa) blotted from the human osteosarcoma cell line G292. Phorbol 12-myristate 13-acetate (PMA) is also capable of inducing ERK phosphorylation, albeit to a lasser degree. The combination of PMA and EGF does not produce a greater response than EGF alone. The role of protein kinase C (PKC) in the EGF-stimulated ERK signaling pathway was further examined by inhibition of PKC with the staurosporine analog, CGP41251, and by down-regulation of PKC via chronic treatment with PMA. Chronic PMA treatment results in a partial inhibition of the EGF-mediated phosphorylation. CGP41251 completely abolishes the increased ERK activity produced by PMA, but the effect of EGF in this regard is potentiated. We conclude that PKC and EGF act through parallel pathways to stimulate ERK phosphorylation and activity. The inhibitor studies, in addition, indicate that activation of PKC may moderate the actions of the EGF pathway via a tonic inhibitory feedback.

[Hand grip strength as a nutritional indicator of patients with oral and maxillofacial malignancies to predict post-operative complications]

The correlation between hand grip strength(HGS),arm muscle circumference(AMC) and creatinine-height index (CHI) were studied in 127 patients with oral and maxillofacial malignancies.Prediction of postoperative complications by using HGS was also attempted in the patients undergoing surgical treatment.The results showed:(1)HGS correlated well with AMC and CHI,indicating that HGS can be used as a nutritional parameter to reflect the skeletal muscle condition(depletion or repletion);(2)comparison of the operative patients whose HGS<85% of the standard value(Group I)with those HGS>/=85% of the standard value(Group II)demonstrated that Group I hand a much higher incidence of postoperative complication(48.4%) than that of Group II (18.5%)(X=9.30;P<0.005),which means that HGS can be served as a nutritional prognostic indicator to predict postoperative complications.

Diuretic effects of irrigating fluids containing mannitol and sorbitol

We studied urine excretion and plasma electrolytes in 38 rabbits during and after a 60-min intravenous infusion of 150 ml/kg of irrigating fluid containing either 3.3-6% of mannitol, 5% sorbitol, or 2.7% sorbitol and 0.54% mannitol (Cytal). The Osmolality of the solutions ranged between 165 and 350 mosmol/kg. The excreted urine volume, peak flow rate, duration of 80% of peak urine flow and the ratio of urine excreted per volume of infused irrigating fluid varied greatly but in direct proportion to the osmolality of each solution. There were no differences between the irrigating fluids with respect to dilution changes in plasma sodium and chloride concentrations. We conclude that the urine flow after infusion of irrigating fluids is governed primarily by the osmolality of the solution. Mannitol has no superior effect over sorbitol as a diuretic.

Glutamine reduces bacterial translocation after small bowel transplantation in cyclosporine-treated rats

Bacterial translocation (BT) of enteric organisms is a major cause of sepsis in patients undergoing small bowel transplantation (SBT). Cyclosporine (CsA) may be toxic to intestinal epithelium and increase the risk of BT. Glutamine (Gln) is the preferred enterocyte fuel and maintains graft epithelial integrity in experimental SBT. This study determined the effects of CsA on mucosal structure and function of transplanted intestinal isograft and examined whether Gln-enriched diet reversed CsA-induced intestinal toxicity. Thirty-three adult Lewis rats underwent resection of the distal 60% of small bowel and received an orthotopic jejunal isograft. Rats received either elemental diet with 2% Gln or the same diet with balanced nonessential amino acids (non-Gln) by gastrostomy for 10 days. CsA (15 mg/kg, im) or olive oil was injected daily. Rats were assigned to four groups: non-Gln with vehicle, non-Gln with CsA, Gln with vehicle, and Gln with CsA. Mucosal villous height, surface area, crypt depth, 14C glucose absorption, BT to mesenteric lymph nodes (MLN), and body weight change were evaluated. The non-Gln with CsA group had the highest incidence of BT (P < 0.001). Gln groups had significantly decreased BT (P < 0.01) and increased crypt depth and villous surface area (P < 0.01) when compared to non-Gln groups. Body weight significantly decreased in CsA groups when compared to non-CsA groups (P < 0.01). These results indicate at CsA significantly decreased body weight and increased BT without decreasing mucosal structure and glucose absorption of intestinal isografts.(ABSTRACT TRUNCATED AT 250 WORDS)

Pectin improves colonic function in rat short bowel syndrome

Short bowel syndrome is characterized by weight loss, diarrhea, and malabsorption. Pectin, a highly fermentable fiber, improves small and large bowel mucosal structure, prolongs intestinal transit, and decreases diarrhea. This study determined if the addition of citrus pectin to an enteral liquid diet (LD) improved structure and absorptive function in the rat jejunum and colon following massive intestinal resection. Twenty-one male Sprague-Dawley rats underwent placement of gastrostomy tube for isocaloric, isonitrogenous feeding and either 60% small bowel and cecal resection or small bowel transection with anastomosis. Animals in each group were then randomly and equally assigned to receive either LD (Enercal Plus, Wyeth) or LD supplemented with 2% citrus pectin for 7 days. Study variables included body weight change, percentage of stool solidity, jejunal villous height (JVH) and crypt depth, colonic crypt depth (CCD), and colonic short-chain fatty acid content (SCFA). Jejunal [14C]glucose absorption and colonic [3H]H2O absorption were measured by a dual in vivo perfusion assay. Resection significantly (P < 0.05) decreased body weight, stool solidity, and colonic SCFA content; enlarged structure (JVH, CCD); and increased absorptive function in the remaining bowel. Pectin significantly decreased (P < 0.05) body weight loss, increased (P < 0.05) stool solidity, and improved (P = 0.05) colonic water absorption following resection without significantly altering mucosal structure. It is concluded that pectin improves colonic absorptive function following massive bowel resection in the rat.

Multi-slice MRI of rat brain perfusion during amphetamine stimulation using arterial spin labeling

When a single coil is used to measure perfusion by arterial spin labeling, saturation of macromolecular protons occurs during the labeling period. Induced magnetization transfer contrast (MTC) effects decrease tissue water signal intensity, reducing the sensitivity of the technique. In addition, MTC effects must be properly accounted for in acquiring a control image. This forces the image to a single slice centered between the labeling plane and the control plane. In this work, a two-coil system is presented as a way to avoid saturation of macromolecular spins during arterial spin labeling. The system consists of one small surface coil for labeling the arterial water spins, and a head coil for MRI, actively decoupled from the labeling coil by using PIN diodes. It is shown that no signal loss occurs due to MTC effects when the two-coil system is used for MRI of rat brain perfusion, enabling three-dimensional perfusion imaging. Using the two-coil system, a multi-slice MRI sequence was used to study the regional effects of amphetamine on brain perfusion. Amphetamine causes significant increases in perfusion in many areas of the brain including the cortex, cingulate, and caudate putamen, in agreement with previous results using deoxyglucose uptake to monitor brain activation.

[Prognostic factors in patients with osteosarcoma]

The prognostic factors in 54 patients with osteosarcoma were studied by analyses of simple factor, multiple linear regression and stepwise regression. The results showed that the significant factors affecting prognosis were tumor cells' DNA content, radiological grade and surgical stage, while tumors' site, maximal diameter proliferating activity indicated by S-phase cell percentage, proliferating index and AgNOR counts had limited influence on the patients' outcome. Besides, patients' sex, age, duration of the symptom, tumors' radiological classification and pathological type bore no relation to survival rate.

p53-independent induction of WAF1/CIP1 in human leukemia cells is correlated with growth arrest accompanying monocyte/macrophage differentiation

The p53 tumor suppressor gene plays a role in controlling a G1 phase checkpoint. The WAF1/CIP1 gene with encodes p21WAF1/CIP1 protein, an inhibitor of cyclin-dependent kinases, is a downstream mediator of p53 function. We examined expression of the WAF1/CIP1 gene and its relationship to growth arrest and differentiation in p53-null human leukemic cell lines. We show that p53-independent induction of WAF1/CIP1 occurs in human leukemia cells treated with 12-O-tetradecanoylphorbol-13-acetate, okadaic acid, or IFN-gamma but not with retinoic acid, vitamin D3, or DMSO. Furthermore, WAF1/CIP1 induction correlates with growth arrest associated with monocyte-macrophage differentiation. The present studies support the idea that WAF1/CIP1 gene expression can be regulated through multiple mechanisms, suggesting that strategies may be designed to restore the G1 checkpoint controls in p53-null cells by targeting these p53-independent mechanisms of WAF1/CIP1 induction.

[Dynamic observation and significance of autoantibody against ADP/ATP carrier in dilated cardiomyopathy]

The presence and dynamic change of autoantibody against ADP/ATP carrier in patients with dilated cardiomyopathy (DCM) was studied by using indirect micro-solid-phase radioimmunoassay. A significant antibody titre was present in 16 of 48 DCM patients and most of them were in early stage of the disease. The titre of anti-ADP/ATP carrier antibody in DCM patients decreased gradually in a follow-up period of three months. The titre of this antibody in the serum from patients with coronary and rheumatic heart disease were within normal limits. Anti-ADP/ATP carrier antibody may play an important role in the pathogenesis, diagnosis and treatment of DCM.

In vivo dynamic MRI tracking of rat T-cells labeled with superparamagnetic iron-oxide particles

Dynamic MRI tracking of rat T-cells in vivo is performed in rat testicles after labeling isolated rat T-cells in vitro with superparamagnetic dextran-coated iron-oxide particles, BMS180549. Tissue inflammation induced by the local injection of the calcium ionophore, A23187, is used to attract labeled T-cells. Gradient-echo MR images of rat testicles show a statistically significant decrease (4%) of the signal intensity in areas of injection of A23187 as early as 30 min after intravenous infusion of 2 x 10(8) labeled T-cells. The signal change reaches its maximum (6-7% decrease) at about 60-120 min after cell infusion. T2-mapping also shows a decrease of T2 in the areas with A23187. Image quantitation, which includes a chemical-shift effect, significantly enhances the sensitivity for detection of superparamagnetically labeled T-cells. Localization of labeled T-cells in rat testicles has been verified by fluorescence microscopy studies of T-cells co-labeled with a lipophilic fluorescent carbocyanine dye, 1,1-dioctadecyl-3,3,3',3'-tetramethyl-lindocarbocyanine perchlorate. These results represent the first successful demonstration of dynamic tracking of specific cells in vivo using MRI.

[Studies on elastase from Flavobacterium. I. Strain screening and enzyme purification]

132 strains bacteria secreting extracellular elastase were isolated from soil samples, 5 of them possessed considerably high elastiolytic activity of more than 100 u/ml. The highest-yield strain No. 17-87 was characterized as Flavobacterium odoratum, studies on the condition of elastase production revealed that its optimum carbohydrate and nitrogen source were glucose and casein respectively, and that it could utilize fowl ferther meal and wheat bran to give 80% relative yield. The culture exhibited maximum elastase activity at 26 degrees C for 21 hours, the productivity could be increased when the aeration was improved. The PAGE-homogenous elastase preparation was obtained from the culture broth by (NH4)2SO4 fractionation, DEAE-cellulose column chromatography and gel filtration on Sephadex G-75. The molecular weight was determined to be 21380 by SDS-PAGE, the elastiolytic activity was optimal at pH7.4 and 50 degrees C. The enzyme was stable over the range of pH4.5-9.5 and below 40 degrees C, but the activity was inhibited completely by Fe3+, Zn2+, Cu2+, Cr3+, Co2+, Ni2+, Hg2+, Ag+.

Rapid diagnosis and treatment of chlamydial conjunctivitis

During December 1989 to December 1992, conjunctival specimens from 63 patients with severe trachoma and 30 with acute follicular conjunctivitis at the eye clinic of Tong Ren Hospital in Beijing, were tested by using direct immunofluorescent technique and amplified enzyme-linked immunoassay (Micro Trak and IDEIA) for chlamydial antigenicity. Trachoma accounted for 97.6% while acute follicular conjunctivitis accounted for 2.4% of the positive cases. Micro Trak and IDEIA tests proved advantageous over the culture method for the detection of Chlamydia trachomatis. In our study, Ofloxacin eye ointment has been proved to be an alternative drug for severe trachoma with better curative effectiveness.

Growth-factor stimulation reveals two mechanisms of retinoblastoma gene inactivation in human myelogenous leukemia cells

Mutation or deletion of the retinoblastoma tumor suppressor gene (Rb) or abnormal Rb protein expression is found in many types of human solid tumors. Low or absent levels of Rb protein are usually found in the leukemic cells of patients with acute myelogenous leukemia (AML) who have an extremely poor prognosis. The absence of Rb protein in these AML cells could result from defects in the Rb gene or from abnormal cell cycle regulation that affects Rb expression. To test these possibilities and to examine whether a low level of Rb protein in AML cells could be up-regulated, we studied the effect that growth factors interleukin 3 (IL3) and granulocyte-macrophage colony stimulating factor (GM-CSF) had on the levels of Rb protein and Rb phosphorylation in AML cells from patients with low Rb or no Rb protein expression. We observed three responses to growth factor-stimulation in leukemic cells taken from patients with AML: (1) some AML cell samples entered a proliferative phase, and Rb protein levels increased with the appearance of normally phosphorylated forms of Rb protein and positive nuclear staining for Rb protein; (2) some AML cell samples became more proliferative, but the levels of Rb protein remained low or absent; and (3) some AML cell samples showed no response. These results indicate that at least two different mechanisms may be responsible for the lack of Rb protein in the leukemic cells of some patients with AML.

IgM anti-A and D SnRNP proteins and IgM anti-dsDNA are closely associated in SLE sera

U1RNP and Sm precipitins occur in systemic lupus erythematosus (SLE) and in overlap syndromes, while precipitins to Ro/SSA and La/SSB occur in SLE and its variants as well as Sjögren's syndrome. In studying IgM and IgG antibodies to these polypeptides by Western blot, we found the expected frequency of antibodies to the A protein of the U1RNP specificity and the D protein of the Sm specificity in sera with precipitins to U1RNP and Sm, but also found the frequent occurrence of both IgM and IgG anti-A and D in SLE sera with no precipitins, and in sera with anti-Ro/SSA and/or anti-La/SSB precipitins, but not in sera from patients with rheumatoid arthritis, polymyositis, scleroderma, or normals. We have studied the sera which bind the A and D polypeptides on Western blot to test their ability to bind native U1RNP (which contain the A and D proteins) in ELISA. The results indicate that most anti-Ro/SSA alone, anti-Ro/SSA, and anti-La/SSB sera as well as SLE sera with no precipitins react preferentially with the denatured A and D proteins. Further study of sera with IgM anti-A and D in Western blot reveals that these sera also frequently contain anti-double-stranded DNA antibodies. These results show that the anti-A and D responses, especially IgM anti-A and D, occur not only in patients with precipitating antibodies to SnRNPs, but in almost half of patients across the lupus spectrum. The extended prevalence of antibodies to the denatured A and D proteins in Western blot is associated with the cross-reaction of antibodies to dsDNA.