Estimation of total collagen and types I and III collagen in canine rotator cuff tendons

The collagen composition of the supraspinatus, infraspinatus, and subscapularis tendons, which form part of the rotator cuff of the shoulder, was determined. Tendons were obtained from adult, male beagle dogs and total collagen was estimated by measurement of hydroxyproline. There was little variation in collagen content among the three major cuff tendons and the quantity approximated that cited in the literature for other tendons. However, the collagen content in the insertion zone of the supraspinatus tendon was significantly higher than in the tendon proper. NaCl fractionation of supraspinatus collagen indicated that type I was the predominant collagen but significant amounts of type III and possibly some type II and type V were also present. Interestingly, there appeared to be more type III collagen in the insertion zone than in the tendon proper, cyanogen bromide digestion and peptide mapping confirmed this finding. The differential collagen composition of the supraspinatus tendon may contribute to the high incidence of tear that is associated with this rotator cuff tendon.

Modifications in the B10 and B26-30 regions of the B chain of human insulin alter affinity for the human IGF-I receptor more than for the insulin receptor

Inversion of the natural sequence of the B chain of human insulin (HI) from ProB28LysB29 to LysB28ProB29 generates an insulin analogue with reduced tendency to self-associate. Since this substitution increases the homology of insulin to insulin-like growth factor-I (IGF-I), we have examined the affinity of a series of insulin analogues with the general modified structure XaaB28ProB29 HI for binding to both human placental insulin and IGF-I receptors. The XaaB28ProB29 HI series is approximately equipotent to HI in binding to the insulin receptor with the exception of when Xaa = Phe, Trp, Leu, Ile, and Gly (40-60% relative to HI). Substitution with basic residues in the B28 position increased the relative affinity to the IGF-I receptor approximately 1.5-2-fold (ArgB28ProB29 > OrnB28ProB29 = LysB28ProB29). Substitution with acidic residues reduced relative affinity for the IGF-I receptor approximately 2-fold (CyaB28ProB29 = GluB28ProB29 > AspB28ProB29). Combination of AspB10 substitution in conjunction with a modification in the B28-29 position (e.g. AspB10LysB28ProB29 HI) showed an additional 2-fold selective increase in affinity for the IGF-I receptor, suggesting that these two effects are additive. Addition of Arg residues at B31-32, on the backbone of either HI or AspB10 HI, increased affinity for the IGF-I receptor 10 and 28 fold, respectively, compared to HI, confirming the significance of enhanced positive charge at the C-terminal end of the insulin B-chain in increasing selectivity for the IGF-I receptor. This relative increase in IGF-I receptor affinity correlated largely, but not completely, with enhanced growth promoting activity in human mammary epithelial cells. In the case of LysB28ProB29 HI, growth activity correlated with dissociation kinetics from the insulin receptor which were shown to be identical with those of human insulin.

Caveolin and MAL, two protein components of internal detergent-insoluble membranes, are in distinct lipid microenvironments in MDCK cells

The MAL proteolipid and caveolin have been identified as components of internal detergent-insoluble membrane microdomains enriched in glycolipids and cholesterol. We have addressed the study of the glycolipid-enriched membranes in cells expressing endogenously only either MAL (Jurkat T cells) or caveolin (epithelial A498 cells) and in polarized MDCK cells which express both proteins simultaneously. Subcellular fractionation by centrifugation to equilibrium in sucrose gradients of Triton X-100 cell extracts from Jurkat and A498 cells revealed that MAL and caveolin are incorporated in detergent-insoluble buoyant membranes independently of the expression of each other and indicated the existence in these cells of insoluble membrane microdomains with either MAL or caveolin. Immunofluorescence analysis in MDCK cells indicated that both MAL and caveolin were located in the Golgi region, whereas caveolin was found in addition at the cell surface. Biochemical analysis in these cells revealed the existence of distinct membrane microenvironments differentially susceptible to detergent solubilization containing either internal MAL or internal plus surface caveolin. The observed heterogeneity within the internal glycolipid-enriched membrane fraction suggests the existence of distinct specialized lipid microenvironments in MDCK cells.

Determination of Deuterium Incorporation into RNA and Protein Components of the Escherichia Coli Ribosome at Biosynthetic Deuteration by Small-Angle Neutron Scattering

A simple method for the determination of deuterium incorporation into nonexchangeable (C-bonded) positions of RNA and protein components of the Escherichia coli ribosome at biosynthetic deuteration has been proposed using small-angle neutron scattering. The theory of the method is based on the joint use of two measurements: one of them is the dependence of neutron scattering intensity at zero angle on the contrast; the second is the dependence of the radius of gyration on the contrast. The main advantage of the method over the standard procedure is that it requires neither separation of the ribosome into RNA and protein components nor a subsequent time-consuming analysis of the hydrolysis products by nuclear magnetic resonance or mass spectrometry.

[Association of pregnancy induced hypertension with human leucocyte antigen system]

OBJECTIVE

To examine whether pregnancy induced hypertension (PIH) is correlated with a polymorphism of human leucocyte antigen (HLA)-DRB1 in the Shanghai population.

METHODS

We determined the HLA-DRB1 types of 17 PIH families and 14 normotension families by DNA typing utilizing the polymerase chain reaction (PCR) and hybridization of Dig-labeled sequence specific oligonucleotide (PCR-SSO).

RESULTS

The antigens frequency and feto-material sharing of HLA-DR4 in PIH were increased and relative to that of the controls, and furthermore the 0405 allele occurred more often in PLH patients.

CONCLUSION

These results suggest that a PIH susceptibility gene is associated with HLA-DRB1 0405. We therefore propose the following working hypothesis; 0405 allele is presumably due to linkage disequilibrium or the possibility that it acts directly as an immune response gene; PIH is correlated with DR4 compatibility between PIH mother and fetus which leads to failure of the mother's nonresponsiveness to fetal antigen. Lack of blocking factor increases the risk for PIH.

The MAL proteolipid is a component of the detergent-insoluble membrane subdomains of human T-lymphocytes

The human mal gene, identified during a search for cDNAs selectively expressed during T-cell development, encodes a highly hydrophobic protein belonging to a group of proteins, termed proteolipids, characterized by their unusual property of being soluble in organic solvents used to extract cell lipids. To study the localization of the MAL protein we have prepared stable transfectants expressing the MAL protein tagged with a c-myc epitope (MAL/c-myc) using human epithelial A-498 cells. Immunofluorescence analysis suggested that MAL/c-myc is localized mainly to cholesterol-enriched structures with a post-Golgi location and, at low levels, in early endosomes. Moreover, extraction of A-498 cell membranes with Triton X-100 (TX100) and fractionation by centrifugation to equilibrium in sucrose gradients demonstrated the presence of MAL/c-myc in the detergent-insoluble buoyant fraction, known to be enriched in glycolipids and cholesterol. To compare the behaviour of MAL in T-cells with that in epithelial A-498 cells, we prepared stably transfected cells expressing MAL/c-myc using human Jurkat T-cells. When TX100 extracts from Jurkat cells were subjected to centrifugation to equilibrium in sucrose gradients we found MAL exclusively in the floating fractions, together with molecules characteristic of the T-cell insoluble complexes, such as the tyrosine kinase p56lck, the glycosylphosphatidylinositol-anchored protein CD59 and the ganglioside GM1. These results, taken together, indicate that the MAL proteolipid is a component of the detergent-resistant membrane microdomains present in T-lymphocytes, and suggest that MAL might play a role in modulating the function of these microdomains during T-cell differentiation.

Association of human papillomavirus type 11 DNA with squamous cell carcinoma of the tongue

A 47-year-old man with a history of a benign papilloma of the tongue 5 years earlier was treated for a squamous cell carcinoma of the tongue with surgical resection. An analysis of the tumor DNA using several methods showed the presence of human papillomavirus (HPV) type 11 sequences that migrated with the high molecular weight cellular DNA, suggesting integration of viral DNA into the cellular genome. A segment of the HPV DNA was cloned from the lesion and shown to be similar to prototype HPV 11 DNA, except for some variability in the viral long control region. The proviral DNA contained part of the L1 region, all of the viral long control region, the entire E6 and E7 open-reading frames, and at least a portion of the E1 region; the E4 region appeared to be deleted. The integration sites of the HPV DNA could not be specifically identified. An analysis of the p53 tumor suppressor gene region of the tumor DNA showed no evidence of mutation. These results suggest that the HPV 11 DNA may have had a role in the origin of the cancer in this patient.

Activation of metabotropic glutamate receptor subtype mGluR1 contributes to post-traumatic neuronal injury

The role of phospholipase C-coupled (group I) metabotropic glutamate receptors (mGluR1 and mGluR5) in post-traumatic neuronal injury was examined using rat in vivo and in vitro models. Traumatic injury to mixed neuronal/glial cultures induced phosphoinositide hydrolysis and caused neuronal death. Pharmacological blockade of group I receptors significantly reduced these effects in vitro and decreased neurological deficits as well as neuronal loss produced by traumatic brain injury in vivo. In contrast, activation of group I receptors by a specific agonist in vitro exacerbated post-traumatic neuronal death in a dose-dependent manner. Antisense oligodeoxynucleotide directed to mGluR1, but not to mGluR5, was neuroprotective in vitro, although each oligodeoxynucleotide reduced the respective receptor-stimulated accumulation of inositol phosphates to a similar degree. Together, these findings suggest that activation of mGluR1 contributes to post-traumatic neuronal injury and that mGluR1 antagonists may have therapeutic potential in brain injury.

Theoretical Study of Ethylene Oligomerization by an Organometallic Nickel Catalyst

The mechanism for ethylene oligomerization by (acac)NiH has been studied using density functional theory (DFT). The transition states for chain propagation and chain termination were optimized and the related reaction barriers calculated. Several possible mechanisms were considered for the chain termination step. Chain termination by beta-hydrogen elimination was found to be energetically unfavorable, and is not likely to be important. Instead, beta-hydrogen transfer to the incoming ethylene unit seems to be operative. The most favorable beta-hydrogen transfer pathway has two transition states. The first leads from a weak pi-complex between an incoming ethylene unit and (acac)NiCH(2)CH(2)R to an intermediate in which the two olefins C(2)H(4) and H(2)CCHR both are strongly pi-complexed to the nickel hydride (acac)NiH. The second barrier takes the intermediate to another weak pi-complex between (acac)NiCH(2)CH(3) and H(2)C=CHR from which the oligomer H(2)C=CHR can be released and the catalyst (acac)NiCH(2)CH(3) regenerated. Due to the mechanism of chain termination, the actual catalyst is proposed to be (acac)NiCH(2)CH(3) whereas (acac)NiH serves as a precursor or precatalyst.

Enhanced natriuretic response to intrarenal infusion of atrial natriuretic factor during ovine pregnancy

Volume-loading and intravenous infusion studies have suggested that the natriuretic response of atrial natriuretic factor (ANF) is blunted or unaltered during pregnancy, but these findings may be influenced by changes in peripheral metabolism or clearance. To better define the direct renal actions of ANF, three doses (0.3, 1.5, and 3.0 pmol.kg-1.min-1) of ANF were infused directly into the renal artery of nonpregnant (n = 7) and 115- to 135-day pregnant (n = 6) unilaterally nephrectomized conscious sheep. Each dose was administered on a separate day according to a protocol that consisted of two 20-min control periods, two 20-min ANF infusions, and three 30-min recovery periods. The levels of basal mean arterial pressure averaged 86 +/- 25 mmHg and were similar and constant throughout all protocols in nonpregnant and pregnant ewes. Glomerular filtration rate (GFR) and renal blood flow (RBF) were increased during pregnancy, but GFR, RBF, and fractional proximal tubular reabsorption were not significantly altered by infusion of ANF. Nonpregnant sheep exhibited a selective renal response that was limited to an increase in urinary sodium excretion (UNaV). Pregnant sheep exhibited a selective renal response that included increases in UNaV and urine flow rate produced by suppression of distal sodium and, presumably, fluid reabsorption. The natriuretic and diuretic response of pregnant sheep was much greater than that of nonpregnant sheep despite a smaller proportional increment in intrarenal ANF concentration. These data suggest that the ovine renal response to ANF is limited to actions on the distal tubule that are enhanced during pregnancy.

Experimental brain injury induces differential expression of tumor necrosis factor-alpha mRNA in the CNS

In the present study, we examined the expression of tumor necrosis factor-alpha (TNF-alpha) mRNA i specific brain regions following experimental lateral fluid percussion traumatic brain injury (TBI) in rats. Adult Sprague-Dawley rats (n = 42) were anesthetized with sodium pentobarbital (60 mg/kg, i.p.) and subjected to lateral fluid percussion brain injury of moderate severity (2.4 atm.) centered over the left temporoparietal cortex, or 'sham' treatment (anesthesia and surgery without injury). Animals were killed by decapitation at 1, 6 or 24 h post injury, brains removed, and tissue samples of left (injured) parietal cortex (LC), right parietal cortex (RC), left adjacent cortex (LA), right adjacent cortex (RA), left hippocampus (LH) and right hippocampus (RH) were prepared. Total RNA was isolated and Northern blot hybridization was performed. TNF-alpha mRNA is expressed as the percent relative radioactivity of macrophage (positive control) RNA. In sham or naive animals, no consistent changes in expression of TNF-alpha mRNA were observed in any of the six brain areas at any times (less than 5%). A marked increase of TNF-alpha mRNA expression was observed in LH (104 +/- 17, P < 0.05 compared with sham), LC (105 +/- 21, P < 0.05) and LA (69 +/- 8, P < 0.01) in the traumatized hemisphere 1 h following injury. An increased TNF-alpha mRNA expression was also observed in LH (46 +/- 8, P < 0.05), LC(30 +/- 3, P < 0.01) and LA(32 +/- 3, P < 0.01) at 6 h which resolved by 24 h following injury. In the contralateral hemisphere, expression of TNF-alpha mRNA was increased in RH (46 +/- 2, P < 0.01) at 1 h and in RA (26 +/- 6%, P < 0.05) at 6 h. These results indicate that following parasagittal fluid percussion brain injury, the temporal expression of TNF-alpha mRNA is altered in specific brain regions, including those of the non-traumatized hemisphere. Post-traumatic alteration in gene expression of TNF-alpha might play an important role in both the acute and regenerative response to CNS trauma.

[An experimental study of regional spontaneous portasystemic shunt in cirrhotic rats]

CCl4 induced splenic portasystemic shunt (SPSS) was measured in 11 CCl4-induced cirrhotic rats and 10 controls, and mesenteric shunt (MPSS) was measured in 11 controls. 125I labeled albumin microspheres was used as nuclear markers for measurement of shunting rate. It was found that, portal resistance, free portal pressure, wedged hepatic venous pressure, portahepatic venous pressure gradient were all elevated markedly in cirrhotic rats, while the volume of portal flow had no significant difference between the two groups. SPSS and MPSS were higher remarkably those that in the normal controls, and SPSS was greater than MPSS significantly. It suggested that splenogastric venous bed is the main area for compensatory shunt and also the dangerous site of bleeding. Portaazygous disconnection is the operation of choice for control of bleeding. However it could impair the mechanism of spontaneous shunting compensation seriously. Disconnection operation combined with splenorenal shunt seems to be a reseasonable consideration.

The Dai minority population of southwest China: heterogeneity of DR2-associated HLA-DRB1,DRB5,DQA1, and DQB1 haplotypes

HLA-DR2 is the most common DR specificity (60.3%) identified in the Dai minority population of Xishuangbanna, Yunna Province, China. We characterized the DRB1, DRB5, DQA1, and DQB1 alleles of 44 unrelated DR2-positive individuals, 11 of whom (15%) were DR2 homozygous. Four DRB1 and four DRB5 alleles encoding DR2 were identified in this population. The most frequent DR2-associated DRB1 alleles were *1602 (gf = 0.164) and *1502 (gf = 0.151). DRB1*1501 (gf = 0.048) and a new allele designated DRB1*1504 (gf = 0.014) were also detected, but *1601 and *1503 were absent. The most frequent DR2-associated DRB5 alleles were *0101 (gf = 0.233) and *0102 (gf = 0.110). Nine different DR2-associated DR/DQ haplotypes were identified. The two most common DR2 haplotypes were DRB1*1602, DRB5*0101, DQA1*0102, DQB1*0502 (hf = 0.142) and DRB1*1502, DRB5*0102, DQA1*0101, DQB1*0501 (hf = 0.075). The new DRB1*1504 allele was found on a single haplotype: DRB1*1504, DRB5*0101, DQA1*0102, DQB1*0502 (hf = 0.017). The Dw2, Dw12, Dw21, and Dw22 haplotypes, present in many other Asian and Mongoloid populations, were not identified in this unique group. However, the Dai minority population is characterized by a relatively large number of diverse DR2 haplotypes and a new DRB1 allele encoding DR2.

Differentiation between emboli and artefacts using dual-gated transcranial Doppler ultrasound

It is well documented that transcranial Doppler ultrasound has the ability to detect cerebral emboli. During intraoperative patient monitoring studies, many signals due to artefact (probe motion, patient movement or surgical manipulation) are also detected and can be difficult to distinguish from genuine embolic events. We have constructed a Doppler system that can simultaneously range-gate at two separate depths, in order to test the hypothesis that it should be possible to distinguish between emboli and artefact by comparing the signal from the two separate regions within the vessel. The classification algorithm is based on the principle that emboli propagate with blood motion (whereas artefacts do not) and thus will be detected sequentially at different depths along the insonated cerebral artery. One hundred thirty-eight (presumed) embolic and 170 artefact signals were analysed. The median (interquartile range) gate separation was 10.01 mm (7.41-10.78 mm). The time delay between detection of embolic signals in the two channels was 11.04 ms (6.24-16.41 ms, but was only 0.08 ms (-0.48(-)+0.64 ms) for artefact (p < 0.0001). Dual-gated Doppler ultrasound is a conclusive and independent method that differentiates emboli from artefact. Incorporation of this system for long-term monitoring may eliminate the need for an experienced observer to be present.

Heat shock response of Trichinella spiralis and T. pseudospiralis

Heat shock proteins (HSPs) were documented for the first time in both somatic extracts and excretory/secretory (ES) products of the infective-stage larvae of Trichinella spiralis and T. pseudospiralis. Larvae recovered from muscles of infected mice were heat shocked at 37, 40, 43 and 45 degrees C in RPMI 1640 medium containing L(-)[35S]methionine. Somatic extracts and ES products of heat-shocked worms were then analysed by SDS-PAGE, autoradiography and laser densitometry. Prominent bands of HSPs were observed at 43 degrees C which is the optimal heat shock temperature. The major HSPs in somatic extracts of T. spiralis were 20, 47, 50, 70, 80 and 86 kDa. When the temperature was increased from 37 to 43 degrees C, the greatest increase in absorbance was observed in HSPs 70 and 86. In vitro translation of mRNA in a nuclease-treated rabbit reticulocyte lysate system showed an increase in the synthesis of the 80 kDa protein. This suggests that the production of HSP 80 is regulated at the transcriptional level. The major HSPs in the ES products were 11, 45, 53 and 64 kDa. In T. pseudospiralis, the major HSPs in the somatic extracts were 20, 26, 31, 50, 53, 70, 80 and 86 kDa, and in the ES products, 11, 35, 37, 41 and 64 kDa.

Interpretation of embolic phenomena during carotid endarterectomy

BACKGROUND AND PURPOSE

Air and particulate emboli are a major source of morbidity during carotid endarterectomy (CEA); however, amplitude overload and poor time resolution have restricted the ability of transcranial Doppler ultrasound to differentiate between the two.

METHODS

We have now overcome these two limitations by (1) rerouting embolic signals away from the audio frequency amplifier to avoid amplitude overload and (2) substituting the Wigner distribution function for the fast Fourier transform to improve time and frequency resolution. Thus, we can now accurately determine embolic duration and embolic velocity, the product of which is the sample volume length (SVL). This measurement represents the physical distance over which an embolic signal can be detected. The underlying hypothesis was that air reflected more ultrasound and would therefore be detected over a greater SVL.

RESULTS

The median SVL (interquartile range) for 75 in vitro air emboli was 1.97 cm (range, 1.70 to 2.35) compared with 0.27 cm (range, 0.16 to 0.43) for 185 particulate emboli detected during the dissection phase of CEA. Off-line analysis on an additional 560 embolic signals detected during different phases of CEA suggested that 46 of 143 (32%) of emboli immediately after shunt insertion were particulate, as were 19 of 33 (58%) occurring during shunting, 28 of 78 (36%) after restoration of flow in the external carotid artery, 23 of 251 (9%) after restoration of flow in the internal carotid artery, and 55 of 55 (100%) of those emboli detected during the early recovery phase.

CONCLUSIONS

This development provides objective physical criteria upon which embolus characterization (particulate/air) can be based. This could have major implications for future patient monitoring with respect to modification of surgical technique and pharmacological intervention.

Control of atrial natriuretic factor by right and left atrial distension in pregnant sheep

Previous studies of the atrial stretch-atrial natriuretic factor (ANF) relationship during pregnancy have employed volume expansion and measured only right atrial pressure (RAP). Consequently, we studied nonpregnant (n = 7) and 115- to 125-day pregnant (n = 7) sheep and assessed the ANF response to changes of RAP and left atrial pressure (LAP) induced by graded balloon inflation. Ewes prepared with vascular catheters and atrial balloons were studied after recovery from preparatory surgical procedures. The basal levels of mean arterial pressure (MAP, 83 +/- 3 mmHg), RAP (2.1 +/- 0.7 mmHg), LAP (4.7 +/- 0.9 mmHg), and heart rate (HR, 102 +/- 6 beats/min) were similar in nonpregnant and pregnant sheep. Pregnancy also resulted in elevation of ANF concentration from 25 +/- 6 to 57 +/- 4 fmol/ml. With right atrial distension, the RAP-ANF relationships were similar in both nonpregnant and pregnant sheep, with a 10-mmHg increase in RAP increasing ANF by an average of 95 +/- 9 fmol/ml. In nonpregnant sheep, the LAP-ANF relationship was more responsive than RAP-ANF because a 10-mmHg increase in LAP resulted in a 193 +/- 10 fmol/ml increase in ANF. Moreover, during pregnancy, the LAP-ANF relationship was significantly more sensitive because a 10-mmHg increase in LAP resulted in a 433 +/- 15 fmol/ml elevation of ANF. These data demonstrate that plasma ANF levels are more responsive to distension of the left atria than to the right. More importantly, the ANF response to left, but not right, atrial distension is enhanced by pregnancy.

Effects of angiotensin II on plasma atrial natriuretic factor in nonpregnant and pregnant ewes

The release of atrial natriuretic factor (ANF) is primarily determined by atrial stretch, but may also be modulated by circulating angiotensin II (AngII). During pregnancy, the circulating concentrations of both ANF and AngII are increased. To further define possible effects of AngII on ANF release, four doses of AngII (0.5, 5, 20, 40 ng.kg-1.min-1) were intravenously infused into five nonpregnant and five pregnant (105-140 days of gestation) ewes alone and during the simultaneous infusion of sodium nitroprusside at doses sufficient to abolish the pressor effects of AngII. Mean arterial pressure (MAP) was increased from 80 +/- 2 to a maximum of 121 +/- 5 mmHg (1 mmHg = 133.3 Pa) in nonpregnant ewes (p < 0.01) and from 79 +/- 2 to 116 +/- 4 mmHg in pregnant ewes (p < 0.01) over the range of AngII infusion. MAP was unaltered during AngII plus nitroprusside infusion, averaging 78 +/- 3 mmHg in nonpregnant ewes and 80 +/- 2 mmHg in pregnant ewes. Basal ANF was higher (p < 0.01) in pregnant sheep than in nonpregnant sheep. With AngII infusion alone, plasma ANF was increased from 13 +/- 2 to 42 +/- 4 fmol/microL in nonpregnant ewes (p < 0.01) and from 23 +/- 5 to 72 +/- 16 fmol/microL in pregnant ewes (p < 0.01). However, during AngII plus nitroprusside infusion, the increases in plasma ANF observed were completely abolished in both nonpregnant and pregnant ewes.(ABSTRACT TRUNCATED AT 250 WORDS)

Experimental brain injury induces expression of interleukin-1 beta mRNA in the rat brain

Cytokines have been shown to be induced following a variety of central nervous system (CNS) insults, and may play a role in the pathophysiological sequelae of CNS injury. In the present study, we characterized the regional expression of interleukin-1 beta (IL-1 beta) mRNA in specific brain regions following experimental lateral fluid-percussion traumatic brain injury (TBI) in rats. Adult Sprague-Dawley rats (n = 42) were anesthetized with sodium pentobarbital (60 mg/kg, i.p.) and subjected to lateral fluid-percussion brain injury of moderate severity (2.4 atm.) centered over the left parietal cortex, or 'sham' treatment (anesthesia and surgery without injury). Animals were sacrificed at 1, 6 and 24 h post injury, brains were removed, and tissue samples of left (injured) parietal cortex (LC), corresponding area in the contralateral right cortex (RC), cortex adjacent to injured parietal cortex (LA), corresponding adjacent area in the right cortex (RA), left hippocampus (LH) and right hippocampus (RH) were prepared. Total RNA was isolated and Northern blot hybridization was performed and the quantity of brain tissue IL-1 beta mRNA is presented as percent relative radioactivity of IL-1 beta positive macrophage RNA which was loaded on same gel.(ABSTRACT TRUNCATED AT 250 WORDS)

Cytotoxicity, DNA adduct formation and DNA repair induced by 2-hydroxyamino-3-methylimidazo[4,5-f]quinoline and 2-hydroxyamino-1-methyl-6-phenylimidazo[4,5-b]pyridine in cultured human mammary epithelial cells

2-Amino-3-methylimidazo[4,5-f]quinoline (IQ) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) are heterocyclic amines (HAs) found in cooked meats. Both compounds are mammary gland carcinogens in rats. The initiation of carcinogenesis by the HAs is believed to be associated with their DNA adduct formation that occurs after metabolic activation of the parent amines via cytochrome P-450-mediated N-hydroxylation and esterification. To assess the capacity of the human mammary epithelium to metabolically activate the HAs, we used the 32P-postlabeling method to measure the levels of DNA adducts in a culture of human mammary epithelial cells exposed to IQ, PhIP or their N-hydroxylamine metabolites. Whereas 50 microM parent amines did not form detectable levels of DNA adducts in cultured human mammary epithelial cells after 24 h incubations, concentrations as low as 1 microM N-hydroxylamines produced detectable levels of adducts after 2 h incubations. N-Hydroxy-PhIP formed higher adduct levels than N-hydroxy-IQ at all concentrations tested. For example, following a 2 h incubation at 50 microM, adduct levels (per 10(7) nucleotides) were 674 and 16 for N-hydroxy-PhIP and N-hydroxy-IQ, respectively. At similar initial adduct levels (10-11/10(7) nucleotides), 60-80% of IQ- and PhIP-DNA adducts were removed after 24 h, indicating that the mammary epithelial cell culture showed efficient repair of HA adducts. Whereas neither IQ nor PhIP was cytotoxic, both N-hydroxy-IQ and N-hydroxy-PhIP were cytotoxic as assessed by a dose-dependent inhibition of colony formation. After exposure to 0.1, 1, 10 or 50 microM N-hydroxy-PhIP (or N-hydroxy-IQ), colony formation was 103 (94), 84 (74), 37 (29) and 3 (2)% of the control values, respectively. Only N-hydroxy-PhIP (at 10 and 50 microM), however, was cytotoxic as assessed by the MTT cell survival assay (which measures the capacity of mitochondria to metabolize a tetrazolium salt). The ability of the N-hydroxylamines to form DNA adducts and to be cytotoxic in a culture of human mammary epithelial cells may implicate these metabolites as proximate carcinogenic forms of IQ and PhIP in the human mammary gland. However, whether there are inter-individual differences in N-hydroxylamine metabolism, adduct formation and repair in human mammary epithelial cells requires further study. The results from this study support the usefulness of cultured human mammary epithelial cells for studies on the genotoxicity and metabolism of the N-hydroxylamines of HA food mutagens.

An appraisal of equilibrium and disequilibrium models of population migration

"This article [discusses] the basic assumptions of the equilibrium and disequilibrium models and their pertinent discussion. In addition, the article examines the conditions under which the two types of models apply in different socioeconomic situations, while paying special attention to the assumptions selected for research of migration in developing countries especially at a time when they begin to move toward a market economy."

Characterization of DNA polymerase-alpha/primase complex from developing embryonic chicken brains

DNA polymerase-alpha and primase activities present in a complex, have been isolated, partially purified, and characterized from embryonic chicken brain. DNA polymerase-alpha activity, characterized by its sensitivity to N-ethyl-maleimide, high sedimentation coefficient (11.3 S), and acidic isoelectric point (5-5.5) was found in all embryonic ages. Primase activity, the enzyme responsible for the initiation of DNA synthesis, co-sedimented with DNA polymerase-alpha activity on a continuous glycerol velocity gradient. A complex containing both DNA polymerase-alpha and primase activities was isolated by DE-23 cellulose column chromatography of cell-free extracts of different embryonic ages of chicken brain. In addition to the primase complexed with DNA polymerase-alpha, a free primase activity was isolated by DE-23 cellulose column chromatography of an ammonium sulfate (0-45%; w/v) precipitated fraction of embryonic chicken brain cell-free extract. DNA polymerase-alpha activity from developing chicken brains in the embryonic stage was purified by immuno-affinity column chromatography. Of all the single-stranded DNA templates tested, primase activity was found to be maximally active with poly dC. Primase activity was not inhibited by a high concentration of alpha-amanitin. The results obtained may provide insight into further understanding of regulation of chromosomal DNA replication in developing tissues.

Renal perfusion pressure and renin secretion in bilaterally renal denervated sheep

To further investigate the influence of renal nerves on renin secretion, the renin secretion responses to step reductions of renal perfusion pressure (RPP) were studied in conscious sheep with innervated kidneys (n = 5) and with bilaterally denervated kidneys (n = 5). The average basal level of RPP in sheep with denervated kidneys (82 +/- 4 mmHg; 1 mmHg = 133.3 Pa) was similar to that in sheep with innervated kidneys (83 +/- 3 mmHg). RPP was reduced in four sequential 15-min steps, to a final level of 54 +/- 2 mmHg in sheep with innervated kidneys and to 57 +/- 1 mmHg in denervated sheep. The renin secretion rate was increased as RPP was reduced in sheep with innervated kidneys. Baseline peripheral plasma renin activity was reduced and there was almost no response of renin secretion rate to reduction of RPP in sheep with denervated kidneys. Also, baseline renal blood flow, urine flow rate, sodium excretion rate, and potassium excretion rate were higher in sheep with denervated kidneys than those with innervated kidneys. Baseline plasma angiotensin II was similar in both groups of sheep. As RPP was decreased, plasma angiotensin II was increased in sheep with innervated kidneys, but was not RPP or renal denervation. In conclusion, hormonal factors, such as angiotensin II and atrial natriuretic factor, do not account for the dramatic suppression of renin secretion in response to the reduction of RPP in sheep with bilateral renal denervation. Renal nerves are a necessary component in the control of renin secretion during reduction of RPP and may contribute to the regulation of baseline plasma renin activity and sodium excretion rate in conscious ewes.

Altered gene structure and tissue expression of islet amyloid polypeptide in the chicken

In mammals, islet amyloid polypeptide (IAPP) is a putative pancreatic peptide hormone that is coproduced and cosecreted with insulin in the beta-cells. However IAPP is also structurally and functionally similar to calcitonin gene-related peptide (CGRP), a 37-amino acid peptide that is expressed predominantly in neurones, and it has been suggested that these peptides arose from a common ancestral gene. In the present study we have characterized an avian IAPP cDNA and gene and have analyzed their expression in various tissues. The cloned chicken IAPP cDNA encodes a 135-amino acid (aa) precursor in which the mature 37-residue IAPP is 80% identical to human IAPP. However, the N-terminal propeptide of chicken proIAPP (55 aa) is considerably longer than that found in the mammalian proIAPPs (9-12 aa) and is comparable in length to that of chicken proCGRP (52 aa). Most of this additional peptide material was found to be encoded in an exon of the cloned chicken IAPP gene that is homologous to exon 3 in the CGRP gene. This exon is absent in the human IAPP gene and thus the exon-intron organization of the chicken IAPP gene more closely resembles that of mammalian CGRP genes. Northern blot analyses demonstrated that chicken IAPP mRNA is expressed predominantly in intestine and brain but at a much lower level in pancreas. The pancreas and intestine contained a single 0.7 kilobase (kb) IAPP transcript while two transcripts, 0.7 kb and 0.9 kb, were detected in brain. Densitometric analysis indicated that IAPP transcripts were 11 times more abundant in brain and intestine than pancreas.(ABSTRACT TRUNCATED AT 250 WORDS)

Colocalization of human papillomavirus type 11 E1[symbol: see text]E4 and L1 proteins in human foreskin implants grown in athymic mice

The most abundant viral mRNA species in tissues infected with HPV 11 consists of two exons, joining a short segment of open reading frame (ORF) E1 to ORF E4, potentially encoding an protein of 10 kDa. E4 gene products have previously been identified by immunohistochemistry in human tissues infected with HPV 1 and HPV 16, and in HPV 11-infected raft cultures. The E1[symbol: see text]E4 mRNA is produced in abundance in HPV 11-infected human foreskin implants grown in athymic mice. In contrast, the L1 mRNA is present at low levels and appears late in the course of infection. To characterize the relationship of these proteins, polyclonal rabbit antisera were produced against bacterially expressed HPV 11 trpE/E1[symbol: see text]E4 and trpE/L1 fusion proteins and tested in an immunohistochemical assay of paraffin-embedded sections of HPV 11-infected human foreskin tissue fixed with 10% buffered formalin phosphate or zinc formalin. In sections fixed with either fixative, the anti-L1 serum stained nuclei of cells in the upper spinous and granular layers. In contrast, the anti-E1[symbol: see text]E4 serum stained the cell membrane and, to a lesser degree, the cytoplasm of cells in the upper spinous and granular layers of tissue fixed with zinc formalin, but not 10% buffered formalin phosphate. In sections treated with both the E1[symbol: see text]E4 and L1 antisera, cell membrane staining occurred in the same cells that exhibited nuclear staining. The HPV 11 E1[symbol: see text]E4 protein appears to be a cell membrane-associated protein. Expression of the HPV 11 E1[symbol: see text]E4 and L1 proteins may be influenced by similar factors in differentiating cells.

Quadrature-to-directional format conversion of Doppler signals using digital methods

Four possible quadrature-to-directional format conversion methods using digital techniques are described. These are the phasing-filter technique, the extended Weaver receiver technique, the Hilbert transform in the frequency domain, and the complex FFT. All methods are implemented to give separated time domain outputs as well as frequency domain outputs. The theoretical descriptions are verified by practical implementations. Each of the methods has been implemented in real-time using a commercially available digital signal processing board.

HLA-DPB1 polymorphism in the Thais of Southeast Asia

In this study we examined DPB1 allele frequencies in five ethnic Thai populations resident in different regions of Thailand and neighboring countries. In contrast to other Asian and Pacific populations such as the Japanese, Chinese, Korean, and Papua New Guineans, where DPB1*0501 has consistently been shown to be the most frequent allele, NE Thais and Thai-Khmers demonstrate a prevalence of DPB1*1301. Comparison of DPB1 allele frequencies in the Thais of SE Asia, with known frequencies in the Chinese and Japanese populations of E Asia, would appear to confirm previous calculations of genetic divergence between these Oriental populations.

Inhibition of plasmid reporter gene expression in CHO cells by DNA adducts of 2-amino-3-methylimidazo[4,5-f]quinoline and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine

2-Amino-3-methylimidazo[4,5-f]quinoline (IQ) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) are two members of a family of carcinogenic heterocyclic amines (HAs) found in cooked meats that form DNA adducts after activation to N-acetoxy derivatives. The ability of IQ- and PhIP-DNA adducts to inhibit gene expression was investigated using a human growth hormone (hGH) reporter gene in a pUC12-based mammalian expression vector under the control of either the herpes simplex virus-1 thymidine kinase promoter or the human immunodeficiency virus-1 long terminal repeat. The plasmids were treated in vitro with 0, 5, 10, or 40 microM N-hydroxy-IQ or N-hydroxy-PhIP in the presence of a 10-fold molar excess of acetic anhydride to generate the N-acetoxy derivatives in situ. The adduct levels in the plasmids were quantitated by the 32P-postlabeling method. The adducted (and control) plasmids were each transfected into repair-deficient or -proficient Chinese hamster ovary cells, and expression of hGH was measured by immunoassay of growth hormone secreted into the cell medium. The results showed that IQ- and PhIP-DNA adducts inhibited gene expression in both plasmids and that the degree of inhibition of hGH production was proportional to the levels of IQ- and PhIP-DNA adducts. The degree of inhibition, however, was independent of the promoter, despite the differences in the strengths of the two promoters to drive hGH production. Repair capacity influenced the extent of inhibition of gene expression by HA adducts since, in general, fewer adducts were needed to inhibit reporter gene expression in repair-deficient cells than in repair-proficient cells. In both cell lines, DNA adducts of PhIP appeared to be more potent in inhibiting hGH expression than adducts of IQ. Whether alteration of gene expression by HA adducts plays a role in the carcinogenicity of these compounds deserves further study.

Effect of dynorphin microinjection in the paraventricular nucleus on the hemodynamic response to hemorrhage in the rat

We studied the effect of dynorphin A-(1-13), dynorphin A-(1-17), des-tyr dynorphin A-(2-17) (inactive at opioid receptor) or normal saline (NS) microinjected into the paraventricular nucleus (PVN) (n = 9/treatment) on mean arterial pressure (MAP), heart rate (HR), cardiac output (CO), stroke volume (SV), and left ventricular stroke work (LVSW) during fixed-volume hemorrhage in conscious rats. Microinjection of dynorphin A-(1-13) (6 nmol) into PVN at 15 min following the termination of fixed volume hemorrhage (8 ml/300 g) significantly decreased MAP from 50 min to 2 hr postinjection (P < 0.05 compared to animals receiving NS), while dynorphin A-(1-17) (6 nmol) significantly decreased MAP from 30 min up to 2 hr postinjection (P < 0.05). Microinjection of des-tyr dynorphin A-(2-17) (6 nmol) into the PVN did not significantly affect MAP following hemorrhage. Recovery of MAP in the dynorphin A-(1-13) and dynorphin A-(1-17) groups following hemorrhage was found to be significantly attenuated compared to the NS group (P < 0.05 and P < 0.01, respectively). Dynorphin A-(1-13) increased heart rate at 20 min and decreased stroke volume at 60 min after microinjection directly into the PVN following hemorrhage when compared with the NS group (P < 0.05). Both dynorphin A-(1-13) and dynorphin A-(1-17) significantly decreased LVSW after PVN injection following hemorrhage compared to NS group (both P < 0.05). No significant effects were observed on CO following microinjection of active or inactive opioid peptides into the PVN following hemorrhage.(ABSTRACT TRUNCATED AT 250 WORDS)

Differences in the power structures of Fourier transform and autoregressive spectral estimates of narrow-band Doppler signals

There is considerable interest in the application of autoregressive (AR) spectral analysis to ultrasonic Doppler signals. Sonograms produced using this technique are, however, very different from those produced using classic Fourier transform methods. Simulations have shown that the heights of the peaks in the AR spectra of narrow-band signals are not necessarily proportional to signal power, and should be used with caution in the context of Doppler signal processing.

Influences of renal nerves and pregnancy on renin secretion in sheep

To investigate the role of the renal nerves in the control of renin secretion during pregnancy, we prepared sheep with one denervated kidney, bilateral renal vein catheters, and an inflatable aortic occluder. The renin secretory responses to step reductions of renal perfusion pressure (RPP) of the innervated and denervated kidneys were compared in eight nonpregnant and nine pregnant (115-130 days gestation) sheep in a normal conscious state. Nonpregnant sheep had average basal levels of mean arterial pressure (MAP) of 91 +/- 3 mmHg, plasma renin activities (PRA) of 2.3 +/- 0.4 ng ANG I.ml-1.3 h-1, and plasma angiotensin (ANG) concentrations of 8.4 +/- 1.1 pg/ml. Pregnant sheep had reduced levels (P < 0.01) of MAP (76 +/- 3 mmHg) but elevated levels of PRA (3.8 +/- 0.4 ng ANG I.ml-1.h 3-1; P < 0.5) and ANG II (12.0 +/- 1.6 pg/ml; P = 0.08). Four successively reduced levels of RPP were observed for 15 min each in both groups of sheep. In both groups, RPP was reduced to a final level of 51 +/- 2 mmHg. The renal venous-arterial difference of PRA (v-aPRA) from the innervated kidneys was increased as RPP was reduced. However, there was little response of v-aPRA to RPP in denervated kidneys. In nonpregnant sheep, the relationship between RPP and renin secretion rate was characterized by an initially slow phase, over which small reductions of RPP resulted in small increases in renin secretion. As RPP fell, this relationship became progressively steeper in nonpregnant ewes.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in host muscles induced by excretory/secretory products of larval Trichinella spiralis and Trichinella pseudospiralis

Excretory/secretory (ES) products obtained by in vitro culture of infective-stage larvae of Trichinella spiralis and T. pseudospiralis were injected intramuscularly at various intervals into mice. Mini-osmotic pumps containing T. spiralis ES products were also implanted subcutaneously and intraperitoneally into rats. The introduction of ES materials into muscles elicited extensive lesions which included dissolution of myofibres, mobilization of mononuclear and polymorphonuclear leucocytes, angiogenesis, hypertrophy of myonuclei, myotube formation, mitosis, muscle bundles becoming rounded and separated from each other, disappearance of Z, I and A bands of sarcomeres, increase in endoplasmic reticulum and Golgi complexes, decrease in glycogen and relocation of mitochondria. These are considered as degenerative/regenerative changes of muscles to injury. Immunodominant epitopes of specific 45-53 kDa glycoproteins in ES antigens of T. spiralis could not be detected in hypertrophic nuclei of injected muscles by using polyclonal and monoclonal antibodies and immunocytochemical methods. ES products of T. spiralis failed to stimulate unsensitized lymphocytes in the lymphocyte transformation test. Infective-stage larvae of T. spiralis released from muscles were found capable of forming nurse cells after injection subcutaneously into rats. It is postulated that the invasion of muscles by trichinellids elicits two independent events, i.e. a general degenerative/regenerative response of muscles and a specific change in genomic expression of myonuclei. The two events are probably mediated by different effector molecules.

A real-time and fine resolution analyser used to estimate the instantaneous energy distribution of Doppler signals

Doppler ultrasound signal analysers in current use require that the signal be stationary within the time interval of processing, and yield average results for that interval. A real-time instantaneous frequency analyser based on the Wigner distribution function (WDF) has been developed, which provides a means of analysing time-varying signals or signals with short stationary time periods, and also produces results with very high instantaneous temporal resolution without causing significant deterioration of frequency resolution. In addition to the real-time processing, the most recent 2.4 s of Doppler signal is stored in the analyser so that the operator can perform further fine analysis and obtain results with very high resolutions in both the time and frequency domains. The pseudo-instantaneous mean frequency (PIMF) and the Pseudo-Instantaneous Power Distribution (PIPD) are calculated and displayed every 4.0 ms in the real-time processing mode, and with a resolution of between 80 microseconds and 2 ms in the fine resolution analysis mode. The analyser utilises an algorithm developed so that the WDF can be calculated efficiently using the conventional Fast Fourier Transform (FFT) method, and the PIPDs are calculated from data that contribute equally.

Extracting instantaneous mean frequency information from Doppler signals using the Wigner distribution function

The Wigner distribution function (WDF) does not require the analysed signals to be stationary within the time segment used for analysis, and instantaneous frequency (IF) information can be obtained from it. Because of the influence of the cross-power of the signal components, however, the interpretation of the IF results is physically clear only for monocomponent signals with infinite data lengths. The IF results for multicomponent signals also suffer from spike problems and are quite unstable even when the signal-to-noise ratio is high. It is suggested that a "pseudo-instantaneous mean frequency," which uses the positive part of the WDF to follow the power distribution changes among frequency components, is used as a simple and rapid way to track frequency changes of Doppler signals. Simulation results show that the pseudo-instantaneous mean frequency does not have the same spike problems and gives stable and relatively accurate information about frequency changes when the sampling frequency is properly chosen.

Cardiovascular effects of microinjection of dynorphin fragments into the nucleus of the solitary tract (NTS) are mediated by non-opioid mechanisms

The nucleus of the solitary tract (NTS) is important for the regulation of cardiovascular homeostasis. In the present study we investigated the effect of dynorphin A-(1-13), dynorphin A-(1-17) and dynorphin A-(2-17) microinjected into the NTS on mean arterial pressure (MAP), heart rate (HR), cardiac output (CO), stroke volume (SV) and left ventricular stroke work (LVSW) following hemorrhage in conscious rats. Following fixed-volume hemorrhage (8 ml/300 g), microinjection of dynorphin A-(2-17) (6 nmol), which is inactive at opioid receptors, into the NTS significantly attenuated the recovery of CO, SV and LVSW following hemorrhage when compared to those animals receiving a microinjection of normal saline (NS) vehicle into the NTS (P < 0.01). NTS microinjection of dynorphin A-(2-17) also increased HR following hemorrhage when compared with the NS group (P < 0.05). No significant effects were observed on CO, SV and LVSW following NTS microinjection of the kappa-opioid agonists, dynorphin A-(1-13) and dynorphin A-(1-17), although dynorphin A-(1-13) microinjection increased HR following hemorrhage when compared with control animals (P < 0.05). Microinjection of all three peptide fragments had no significant effect on MAP when compared with MAP of the control group following hemorrhage. The results of this study suggest that dynorphin A-(2-17) in the NTS can attenuate the compensatory cardiovascular responses to hemorrhage, perhaps via a non-opioid mechanism.

Clinical observation on treatment of bradyarrhythmia with Chinese herbal medicine

This paper reports on treatment of 62 cases of bradyarrhythmia with Fu Ben Zeng Mai Tang, a decoction of herbal medicine which has the effect of warming and tonifying the heart and kidney, reinforcing qi and improving blood circulation. The result indicates that it is effective for quickening the heart rhythm, improving the symptoms and regulating the function of sinoatrial node. It is also good for regulating the function of endocrine and the immune and nervous system. This therapy was compared with Western medicine in the treatment of 24 cases.

Cloning and analysis of the gene encoding hummingbird proinsulin

Because hummingbirds exhibit the highest mass-specific metabolic rates seen among vertebrates and rely on sugars as their main energy source, we have investigated the structure of hummingbird insulin (Selaphorus rufus) to determine whether it possesses structural adaptations that increase its receptor binding affinity (potency). We report here the nucleotide sequence of hummingbird proinsulin determined from hummingbird genomic DNA. The predicted amino acid sequence of the A-chain of hummingbird insulin is identical to that of chickens and the B-chain differs by only one amino acid at a noncritical position, B2 (Val in hummingbird and Ala in chicken). These findings suggest that alterations in secretory and metabolic dynamics of insulin are of greater importance than changes in binding affinity in the adaptation to states of high carbohydrate flux in these very energetic organisms.

Suggested approaches for research protocols involving the potential for life-threatening reactions

These guidelines are intended to reduce the potential for serious or life-threatening reactions when clinical research is conducted. The following issues were addressed: identifying the risks involved in the research, providing adequate safeguards in the protocol design and during withholding of medication, anticipating risks, minimizing the chances for human error, providing resuscitative equipment sufficient to deal with the most serious anticipated life-threatening reactions, planning for medical support in case of a life-threatening emergency, and optimizing the use of medical personnel and expertise to handle emergency situations. The guidelines also discuss important general issues about protocol design and implementation and the human subject consent form, which should facilitate the approval of protocols by the governing institutional review board. The guidelines are not meant to be inflexible or applicable to all research situations. However, it is our hope that they will allow for clinical research to be conducted in a manner that affords the research subjects a high degree of protection from unnecessary and possibly fatal injuries.

Regulation of the gene expression of preproenkephalin in the rat brain: influence of hemorrhage

In the present study, we examined the expression of the gene encoding for the production of the opioid peptide enkephalin in specific brain regions during hemorrhage in the conscious rat. Rats were subjected to fixed-volume (8 ml/300 g) bleeding via jugular vein within 10 min. Total RNA was isolated from rat brain tissue using the hot phenol/chloroform method. Preproenkephalin transcript levels were quantified using Northern blot hybridization of total RNA with alpha-32P-labeled cDNA probe, and autoradiograms were scanned with a densitometer. The ppENK transcript in midbrain was significantly elevated following one and two hours of hemorrhage compared to control group (P < 0.01). The ppENK transcript in spinal cord was also significantly increased after two hours of hemorrhage, when compared with control group (P < 0.01). In the brainstem, ppENK transcript was significantly decreased after both 1 and 2 hr of hemorrhage compared with control values (P < 0.01). These results indicate that hemorrhage acutely changes levels of the transcript of ppENK in specific brain regions. It is possible that the changes in brainstem ppENK transcript may be a mechanism by which certain inhibitory effects of enkephalins on important brain cardiovascular regulatory centers are mediated.

Effect of dynorphin microinjection in the anterior hypothalamus (AV3V) region on the hemodynamic response to hemorrhage in the rat

The region surrounding the anteroventral part of the third ventricle (AV3V) is important for the regulation of cardiovascular homeostasis. In the present study we investigated the effect of the kappa-opioid receptor agonists dynorphin A-(1-17) and dynorphin A-(1-13) microinjected into the AV3V region on mean arterial pressure (MAP), heart rate (HR), cardiac output (CO), stroke volume (SV), and left ventricular stroke work (LVSW) during fixed-volume hemorrhage in conscious rats. During fixed-volume hemorrhage (8 ml/300 g), dynorphin A-(1-17) (6 nmol), microinjected into the AV3V, significantly decreased MAP up to 30 min postinjection (P < 0.05). Recovery of MAP, SV, and LVSW in the dynorphin A-(1-17) group following hemorrhage was found to be significantly attenuated compared to that in animals receiving microinjection of normal saline (NS) vehicle into the AV3V (P < 0.05). Hypothalamic microinjection of dynorphin A-(1-13) (6 nmol) also attenuated the recovery of SV following hemorrhage compared with the NS group (P < 0.05). No significant effects were observed on HR or CO following microinjection of dynorphin into the AV3V region. The results of this study suggest that activation of the kappa-opiate receptor system in the AV3V region of the hypothalamus can attenuate the compensatory cardiovascular responses to hemorrhage.

Cell-free transmission of Vif mutants of HIV-1

To determine the phenotype of human immunodeficiency virus type 1 (HIV-1) defective in the production of Vif, mutations were introduced into the vif gene of infectious molecular clones of the LAI, MAL, and ELI strains. Previous results had demonstrated that viruses derived from these wild type clones display different replicative capacities on peripheral blood mononuclear cells (PBMC) and different tropisms for CD4-positive cell lines. Using cell-free infection, Vif mutants of LAI, MAL, and ELI were found to have delayed kinetics and to produce less virus than their corresponding wild type viruses when propagated on most permissive cell lines. An additional mutation in the vpr gene in the LAI strain had no effect on this phenotype. However, on one T cell line, the H9 cell line, two Vif mutants of LAI and a Vif.Vpr double mutant were unable to replicate. Furthermore, Vif mutants from all three strains were only able to establish a productive infection on PBMC by coculture and not by cell-free infection. No defects in the processing of the virion proteins or the release of particles in the Vif mutants were detected.

Clinical features of multiple organ failure in the elderly

Multiple organ failure (MOF) in the elderly is a new syndrome evolved from multiple organ chronic diseases on the basis of multiple organ dysfunction in the aged. Its characteristics are clinically different from those of MOF due to serious trauma. 122 cases of MOF were analysed retrospectively and their clinical features discussed. MOF with a long course is the natural presentation in many of the elderly before death. Its main precipitating factors are pulmonary infection, metastatic carcinoma, cardiac attack, etc. The sequence of a failure in organs is heart, lung, kidney, liver, etc. The mortality is similar to that of MOF due to trauma. However, those suffering from 4-organ failure can still survive, and instead, the renal failure can be mostly fatal. More attention should be paid to the prevention of MOF in the elderly so as to shorten its developing course.

Mathematics achievement of children in China and the United States

First and fifth graders in Beijing and Chicago were given a battery of mathematics test. Whether tested with problems requiring solely computation or with ones requiring application of knowledge about mathematics, American children's performance was consistently inferior to that of Chinese children. Interviews with American children suggested that they like mathematics, believe they are doing well in mathematics, and do not perceive mathematics as a difficult subject. American children's poor performance appears to be attributable, in part, to low motivation for devoting more attention to mathematics. Low standards held by American parents for academic achievement and lower interest in teaching mathematics by American teachers appear to contribute to American children's poor performance.