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PubMed2005

A parallel group analysis of tonsillectomy using the harmonic scalpel vs electrocautery.

OBJECTIVE: To evaluate efficiency and postoperative morbidity in tonsillectomy using the harmonic scalpel (HS) vs conventional electrocautery (EC). DESIGN: A retrospective medical chart review of all patients who underwent tonsillectomy at a single children's hospital during a 32-month period from January 2001 to August 2003. PATIENTS: The charts of 605 patients who underwent tonsillectomy or adenotonsillectomy were reviewed. The patients were stratified into 2 groups based on the dissecting instrument used (HS vs EC). Each group consisted of 2 subcategories based on age (< or =7 years and >7 years). Data collected included age, sex, operative indication, operative time, postanesthetic recovery room time, pain scale scores, postoperative admissions, and postoperative morbidities. RESULTS: There were significant differences in mean age (P<.001), mean weight (P<.001), and indication for surgery (P<.001) between the 2 methods: HS patients were younger, weighed less, and more often had obstructive symptoms as their primary operative indication compared with the EC group. Average operative times were not significantly different between methods. No differences were noted with respect to recovery time (HS group, P = .10; EC group, P = .30), postoperative oxygen requirements (HS group, P = .07; EC group, P = .09), and postoperative pain scores (HS group, P = .31; EC group, P = .58). There was a significant difference in postoperative admissions between the 2 methods in patients 7 years or younger (P = .005). Finally, we noted a significant difference in postoperative bleeding between the HS (2/292) and EC (13/313) methods when the data were compared per age group (P = .006), but the overall bleeding rate was not statistically significant owing to the small number of total bleeding instances (15/605). CONCLUSIONS: Recent prospective studies indicate that the HS provides advantages over conventional EC with respect to postoperative pain and return to normal activity. This study shows that HS tonsillectomy was as efficient as the conventional EC method. In addition, there was evidence that the rate of postoperative bleeding was significantly reduced by using the HS vs conventional EC.

Adenoidectomy↗
PubMed1997

Membrane cation and anion transport activities in erythrocytes of hereditary spherocytosis: effects of different membrane protein defects.

Hereditary spherocytosis (HS) is due to different membrane protein defects (i.e., deficiency of spectrin and ankyrin, band 3, or band 4.2). In order to gain new insight into the relationships between band 3 function and proteins associated with the cytoskeleton, we studied erythrocyte anion transport activity in HS characterized by different membrane protein defects. Anion transport activity was increased in HS due to partial band 4.2 deficiency or to band 4.2 absence, while in HS associated with deficiency of spectrin + ankyrin or band 3, the anion transport results were normal or decreased, respectively. Moreover, since HS erythrocytes are characterized by an increased Na and a decreased K, we studied the principal membrane cation transport pathways. Activity of the Na/K pump was increased in all HS studied, while no changes in Na/K/2Cl cotransport and Na/Li exchange were evident between control and HS as well as between forms of HS associated with different membrane protein defects. K/Cl cotransport activity was decreased in all HS studied compared to normal red cells. In all HS, passive membrane permeability to Na and K was increased compared to normal erythrocytes. The increased Na and the low K content can be attributed to the abnormal membrane permeability to cations, which is not related to a specific membrane protein defect.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1997

Heparan sulfate proteoglycan expression in human lung-cancer cells.

Heparan sulfate (HS) functions as a co-factor in several signal-transduction systems that affect cellular growth, differentiation, adhesion and motility. HS, therefore, may also play a role in the malignant transformation of cells, tumor growth, cell invasiveness and the formation of tumor metastases. To explore this hypothesis, we analyzed the expression of HS and heparan sulfate proteoglycan (HSPG) in histological sections of human lung-cancer tissues and assayed for the presence of HSPGs in extracts of human lung-cancer cell lines, using a panel of native HS-, delta-HS- and HSPG (syndecan, glypican, CD44 and perlecan) core protein-specific monoclonal antibodies. Compared to normal epithelia, non-small-cell lung carcinomas, particularly poorly differentiated tumors, often expressed reduced amounts of the major cell surface-associated HSPGs (most consistently of syndecan-1). CD44 or CD44-variant proteins, in contrast, were found on all tumor cells, irrespective of their differentiation. Perlecan, a matrix-associated HSPG found in the basement membrane of normal bronchial epithelium, was consistently undetectable in invasive bronchogenic carcinomas. Staining reactions for native HS were consistently reduced in squamous-cell lung carcinomas, in the cells in contact with the stroma and in the less differentiated areas of these tumors. Reactions for delta-HS, however, were not reduced, suggesting a structural change in the HS of these tumor cells. Poorly differentiated adenocarcinomas, in contrast, yielded strong HS and delta-HS reactions. Marked differences in HSPG expression also were observed among various non-small-cell lung carcinoma cell lines. Our results suggest that poorly differentiated lung tumors have markedly altered patterns of HSPG expression, which may contribute to their invasive phenotype.

Adenocarcinoma↗
PubMed1997

Effect of capsaicin on airway responsiveness to hypertonic saline challenge in asthmatic and non-asthmatic children.

Recurrent cough and asthma are common problems in children. In the evaluation of children with recurrent cough, the sequential measurements of airway responsiveness (AR) and capsaicin cough receptor sensitivity may be useful. However, the effect of capsaicin on AR induced by an indirect stimulus such as hypertonic saline (HS) is not known. Current evidence suggests that a common pathway is involved in both capsaicin and HS challenges. This study was designed to determine whether inhalation of capsaicin for the cough receptor sensitivity test before HS challenge will alter AR of asthmatic and non-asthmatic children to that challenge. Twenty-one children (12 asthmatics, 9 non-asthmatics; mean age, 11.3 years) performed the HS challenge alone or 2 min after capsaicin inhalation on 2 different days in random order. The end point of the capsaicin inhalation was when > or = 5 coughs were stimulated from a single inhalation. The power of the study was > 90% at a significance level of 0.05. Capsaicin inhalation prior to HS challenge did not alter the AR of normal children. In the asthmatic group, the PD15 (provocation dose causing a fall in forced expiratory volume in 1 s of > or = 15% from the baseline) without prior inhalation of capsaicin (mean, 2.44 +/- SEM 1.21 ml) was not significantly different from that when HS challenge was performed after capsaicin inhalation (mean, 2.19 +/- SEM 0.83 ml). The mean of the difference in log PD15 of the HS challenge with and without capsaicin was -0.02 (95% CI, -0.16, 0.12), i.e. within the equivalence range of the HS challenge in children with asthma. We conclude that in normal and asthmatic children, capsaicin inhalation does not alter AR to HS; consequently the capsaicin cough sensitivity test can be performed validly before an HS challenge.

Adolescent↗
PubMed1999

Hippocampal N-methyl-D-aspartate receptor subunit mRNA levels in temporal lobe epilepsy patients.

Changes in the subunit stoichiometry of the N-methyl-D-aspartate (NMDA) receptor (NMDAR) alters its channel properties, and may enhance or reduce neuronal excitability in temporal lobe epilepsy patients. This study determined whether hippocampal NMDA receptor subunit mRNA levels were increased or decreased in temporal lobe epilepsy patients compared with nonseizure autopsy cases. Hippocampal sclerosis (HS; n = 16), non-HS (n = 10), and autopsy hippocampi (n = 9) were studied for NMDAR1 (NR1) and NR2A-D mRNA levels by using semiquantitative in situ hybridization techniques, along with neuron densities. Compared with autopsy hippocampi, non-HS and HS patients showed increased NR2A and NR2B hybridization densities per dentate granule cell. Furthermore, non-HS hippocampi showed increased NR1 and NR2B mRNA levels per CA2/3 pyramidal neuron compared with autopsy cases. HS patients, by contrast, showed decreased NR2A hybridization densities per CA2/3 pyramidal neuron compared with non-HS and autopsy cases. These findings indicate that chronic temporal lobe seizures are associated with differential changes in hippocampal NR1 and NR2A-D hybridization densities that vary by subfield and clinical-pathological category. In temporal lobe epilepsy patients, these findings support the hypothesis that in dentate granule cells NMDA receptors are increased, and excitatory postsynaptic potentials should be strongly NMDA mediated compared with nonseizure autopsies. HS patients, by comparison, showed decreased pyramidal neuron NR2A mRNA levels, and this suggests that NMDA-mediated pyramidal neuron responses should be reduced in HS patients compared with non-HS cases.

Adolescent↗
PubMed2006

A variety of spin-crossover behaviors depending on the counter anion: two-dimensional complexes constructed by NH...Cl- hydrogen bonds, [FeIIH3LMe]Cl.X (X = PF6 -, AsF6 -, SbF6 -, CF3SO3 -; H3L(Me) = Tris[2-{[(2-methylimidazol-4-yl)methylidene]amino}ethyl]amine).

A family of spin-crossover (SC) complexes, [Fe(II)H(3)L(Me)]Cl.X (X(-) = PF(6) (-), AsF(6) (-), SbF(6) (-), CF(3)SO(3) (-)), 1-4, has been synthesized, in which H(3)L(Me) denotes the hexadentate N(6) tripod-like ligand tris[2-{[(2-methylimidazol-4-yl)methylidene]amino}ethyl]amine, containing three imidazole groups, with a view to establishing the effect of the counter anion on the SC behavior. These complexes have been found to crystallize in the same monoclinic crystal system with similar cell dimensions. The general crystal structure consists of a two-dimensional (2D) extended network constructed by NH...Cl- hydrogen bonds between Cl- and the imidazole NH groups of three neighboring [Fe(II)H(3)L(Me)]2+ ions, while the anion X exists as an isolated counter anion and occupies the space between the 2D sheets. Magnetic susceptibilities and Mössbauer spectra have revealed a variety of SC behaviors depending on the counter anion, including a one-step HS<==>(HS + LS)/2 (1, X = PF(6) (-)), a two-step HS<==>(HS + LS)/2<==>LS with a slow thermal relaxation (2, X = AsF(6) (-)), a gradual one-step HS<==>LS (3, X = SbF(6) (-)), and a steep one-step HS<==>LS with hysteresis (4, X = CF(3)SO(3) (-)). The complexes assume the space group P2(1)/n in the HS state, P2(1) in the HS + LS state, and P2(1)/n in the LS state. The Fe-N bond lengths and the N-Fe-N bond angles are indicative of the HS, HS + LS, and LS states. The molecular volumes, V, of the counter anions have been evaluated by quantum-chemical calculations as follows: 53.4 A(3) (BF(4) (-)), 54.4 A(3) (ClO(4) (-)), 73.0 A(3) (PF(6) (-)), 78.5 A(3) (AsF(6) (-)), 88.7 A(3) (SbF(6) (-)), and 86.9 A(3) (CF(3)SO(3) (-)). The size and shape of the counter anion affects the flexible 2D network structure constructed by the hydrogen bonds, leading to modifications of the SC behavior. These estimated relative sizes of the counter anions correlate well with the observed SC behaviors.

Chlorine↗
PubMed2006

Mössbauer investigation of the photoexcited spin states and crystal structure analysis of the spin-crossover dinuclear complex [{Fe(bt)(NCS)(2)}(2)bpym] (bt=2,2'-bithiazoline, bpym=2,2'-bipyrimidine).

The crystal structure of the complex [{Fe(bt)(NCS)(2)}(2)bpym] (1) (bt=2,2'-bithiazoline, bpym=2,2'-bipyrimidine) has been solved at 293, 240, 175 and 30 K. At all four temperatures the crystal remains in the P space group with a=8.7601(17), b=9.450(2), c=12.089(3) A, alpha=72.77(2), beta=79.150(19), gamma=66.392(18) degrees , V=873.1(4) Angstrom(3) (data for 293 K structure). The structure consists of centrosymmetric dinuclear units in which each iron(II) atom is coordinated by two NCS(-) ions in the cis position and two nitrogen atoms of the bridging bpym ligand, with the remaining positions occupied by the peripheral bt ligand. The iron atom is in a severely distorted octahedral FeN(6) environment. The average Fe--N bond length of 2.15(9) Angstrom indicates that compound 1 is in the high-spin state (HS-HS) at 293 K. Crystal structure determinations at 240, 175 and 30 K gave a cell comparable to that seen at 293 K, but reduced in volume. At 30 K, the average Fe--N distance is 1.958(4) Angstrom, showing that the structure is clearly low spin (LS-LS). At 175 K the average Fe--N bond length of 2.052(11) Angstrom suggests that there is an intermediate phase. Mössbauer investigations of the light-induced excited spin state trapping (LIESST) effect (lambda=514 nm, 25 mW cm(-2)) in 1 (4.2 K, H(ext)=50 kOe) show that the excited spin states correspond to the HS-HS and HS-LS pairs. The dynamics of the relaxation of the photoexcited states studied at 4.2 K and H(ext)=50 kOe demonstrate that HS-HS pairs revert with time to both HS-LS and LS-LS configurations. The HS-LS photoexcited pairs relax with time back to the ground LS-LS configuration. Complex [{Fe(0.15)Zn(0.85)(bt)(NCS)(2)}(2)bpym] (2) exhibits a continuous spin transition centred around 158 K in contrast to the two-step transition observed for 1. The different spin-crossover behaviour observed for 2 is due to the decrease of cooperativity (intermolecular interactions) imposed by the matrix of Zn(II) ions. This clearly demonstrates the role of the intermolecular interactions in the stabilization of the HS-LS intermediate state in 1.

Journal Article↗
PubMed1992

Transcriptional inhibition of endotoxin-induced monokine synthesis following heat shock in murine peritoneal macrophages.

The role of heat shock proteins (HSP) during the inflammatory response has been controversial. The effect of heat shock (HS) on the synthesis of the monokines tumor necrosis factor (TNF) and interleukin 1 (IL-1) by endotoxin-stimulated thioglycollate-elicited peritoneal macrophages was investigated. HS was deemed to have affected macrophages if a 70 kD HSP appeared on SDS gels; identity of this protein as the highly conserved HSP70 was then confirmed by immunoprecipitation. Maximal increases in HSP70 were apparent 2-5 h after HS at 45 degrees C for 12 min. Synthesis of HSP70 was no longer detected 24 h post HS. A reciprocal relationship between HSP70 and TNF was apparent in kinetic studies. TNF was not detected in culture supernatants if macrophages were endotoxin-stimulated 2 to 6 h after HS; however, the same stimulation 24 h later induced significant TNF secretion. RNA analysis of HS and non-HS macrophage cultures demonstrated a 60-fold reduction in TNF message in the HS macrophages 1 h after endotoxin stimulation. TNF mRNA levels remained depressed at 6 h while the HSP70 message had increased 30-fold. The ability of HS macrophages to ingest antibody-coated erythrocytes was not significantly affected following heat treatment. Macrophage response to HS can be said to inhibit transcription of inducible monokines while retaining other macrophage functions.

Animals↗
PubMed2004

Reactive oxygen species may influence the heat shock response and stress tolerance in the yeast Saccharomyces cerevisiae.

Moderate levels of reactive oxygen species (ROS) have been implicated as second messengers in a number of biochemical pathways, and in animal cells have been associated with the activation of the heat shock response (HSR). Here, using an intracellular probe, we demonstrate that differential accumulation of ROS in the yeast Saccharomyces cerevisiae is strongly associated with differential induction of an HS reporter gene over a range of heat shock temperatures. There was a good correlation between cellular ROS levels and the levels of HS-induced reporter gene expression between 37 degrees C and 44 degrees C, both reaching maximal values at 41 degrees C. Furthermore, the addition of 150 microM H2O2 to the yeast cells during heat treatment resulted in a 3 degrees C decrease in the temperature required for maximal induction of the HS expression vector--an increased HS sensitivity that corresponded to a concomitant increase in ROS levels at these lower HS temperatures. Conversely, cells treated with 10 mM of the antioxidant ascorbic acid required a temperature that was 2 degrees C above that required in untreated controls for maximal induction of the HS expression vector. This decreased HS sensitivity corresponded to a decrease in ROS levels at these higher HS temperatures. Finally, cell viability assays reveal that intrinsic thermotolerance remains high in control cells despite concomitant decreases in HS-reporter gene expression and ROS accumulation between 41 degrees C and 44 degrees C. We conclude that the sensitivity of the yeast HSR is strongly associated with ROS accumulation, and suggest that ROS-mediated signalling ensures cooperation between the HS and the antioxidant responses.

Acclimatization↗
PubMed1998

Dissociation of heat shock proteins expression with ischemic tolerance by whole body hyperthermia in rat heart.

Heat shock (HS) results in the expression of heat shock proteins (hsp) and confers tolerance against subsequent ischemic injury. We examined the extent of myocardial protection in vivo, and determined the level of hsp expression induced by HS as a function of time. Anesthetized rats were subjected to HS by raising core temperature to 42 degrees C for 15 min and they were then allowed to recover from 2 to 30 h (n = 8-11 for each time point). At the appropriate time, animals were subjected to 30 min of ischemia via ligation of the LAD, followed by 90 min of reperfusion. Infarct size was determined by tetrazolium staining and hsp expression was assessed by Western blots. Following ischemia/reperfusion, the infarct sizes (% risk area) were 51.3 +/- 3.7, 41.0 +/- 7.7, 48.0 +/- 6.9 after 2, 4 and 12 h of HS, which were not significantly different from 39.2 +/- 2.75 in non heat-shocked animals (P > 0.05). In contrast, the infarct size was reduced significantly to 11.0 +/- 3.1% in 24 h HS group (P < 0.01 v non-heat-shocked control, 2, 4 and 12 h HS groups), but increased back to 40.0 +/- 3.2% (P < 0.01) by 30 h after HS. No major significant differences in the mean arterial blood pressure, heart rate or rate pressure product was observed between different groups. The synthesis of 72- and 27-kD hsp in HS groups was rapid, reaching > 80% of maximum within 4 h of initial insult and peaked by 12 h, whereas the protective effect of HS was absent at these time points. We conclude that ischemic tolerance afforded by HS cannot be solely explained on the basis of hsp expression, and may be dependent on factors such as post-translational modifications, translocation of hsps or some other as yet unidentified factors.

Animals↗
PubMed1986

Heat shock responses in polytene foot pad cells of Sarcophaga bullata.

Heat shock induces a single large puff (hs puff) near the tip of chromosome arm EL in polytene foot pad cells of fly pupae (Sarcophaga bullata). The inducible hs locus is constitutively active, invariably forming a small puff, which can be maximally activated in cells of the dorsal epidermis or in trichogen cells at any time during the lifetime of mature polytene chromosomes. Both in vivo and in cultured food pads, maximal puff induction occurs at 37 degrees C. At the same temperature, normal development of puffing patterns continues undisrupted for several days. A few specific hs proteins are vigorously induced at 37 degrees C, also without disrupting patterns of normal protein synthesis. Rates of normal protein synthesis in cultured food pads and rates of pupal development are enhanced up to about 39 degrees C. During heat shock at 41 degrees-44 degrees C protein synthesis becomes completely dominated by the production of hs proteins. The severe or complete suppression of most of the proteins normally made is followed by developmental arrest. There is also a decline of transcription (chromosomal uridine incorporation) between 37 degrees and 44 degrees C, which appears to affect all chromosomal loci proportionally, including the hs locus. The hs puff is no longer maximally induced at 41 degrees-44 degrees C, but the expanded puff now persists indefinitely, whereas below 39 degrees C, initial puff expansion is always followed by at least partial puff regression. The control of the duration of the puffing response appears to be entirely independent of protein synthesis, e.g., complete inhibition of protein synthesis by cycloheximide fails to prolong transient puffing responses. Canavanine also has no effect on puff regression. Heat shock above 45 degrees C arrests all RNA and protein synthesis within 30 min. RNA synthesis is resumed immediately after shift-down to 25 degrees C, not only at the hs locus, but at most or all previously active loci. Protein synthesis is also resumed immediately, but it is almost completely restricted to the production of the major hs protein (hsp-65, equivalent to hsp-70 of Drosophila melanogaster). Extreme heat shock also triggers maximal puffing responses at the hs locus, but actual puff expansion is delayed and only occurs hours after shift-down in the wake of a surge of hsp-65 synthesis. Following these delayed hs responses pupal thermotolerance starts increasing and protein synthesis returns to normal.

Animals↗
PubMed1992

Hellp syndrome: incidence and maternal-fetal outcome--a prospective study.

OBJECTIVE: To determine the incidence of Hellp syndrome (HS) and the maternal fetal outcome associated with its occurrence. DESIGN: A prospective study during a 6-month period. SETTING: The department of obstetrics and gynecology and the Intensive Care Unit of a 700 bed teaching hospital. PATIENTS: Sixty-two consecutive preeclamptic and eclamptic women. MEASUREMENTS AND RESULTS: All patients were systematically investigated for the biological markers of HS. The effects of the occurrence of HS on maternal and fetal prognosis were evaluated by comparing for prognosis indicators usually assessed in gravidic hypertension, pre-eclamptic and eclamptic woman who exhibited HS (HS+ subgroup) with HS free patients (HS- subgroup). HS was found in 12 out of the 62 pre-eclamptic and eclamptic women (19.3%). Its occurrence was associated with higher maternal mortality (16.7% vs 0%; p = 0.03), a greater incidence of eclamptic crisis (50% vs 20%; p = 0.03), severe hypertension (33% vs 8%; p = 0.03) and episodes of acute renal failure (66% vs 30%; p = 0.02). Mean proteinuria was also higher in HS+ patients (4.6 +/- 3.3 vs 2.2 +/- 2.5 g/day; p = 0.001). However, fetal outcome was not significantly altered. CONCLUSION: Pre-eclampsia and eclampsia may be more severe in the presence of HS with a worsening of maternal prognosis while fetal outcome seems not altered.

Adult↗
PubMed1998

Formation, properties and antimicrobial activities of cotton xanthate-Cu(II)-homosulfamine complex.

To develop a cotton derivatives with prolonged antimicrobial activities, homosulfamine (Hs) was coupled to cotton xanthate (CX) via chelate bond in the presence of Cu(II) ion by one- and two-bath processes. In one-bath process, CX was treated with Cu(II)-Hs solution. In two-bath process, CX was treated with Cu(II) ion solution to produce CX-Cu(II) complex, which was isolated and treated in turn with Hs solution. Effects of concentration, Cu(II)/Hs ratio, and pH on the binding of Hs were investigated at 10 degrees C. In one-bath process, binding of Hs took place readily with optimum pH around 5-6. The amount of binding increased to give a maximum within 5 min and decreased slowly to establish an equilibrium within an hour. In two-bath process, binding of Hs was much lower than that of one-bath process. Release of Hs from CX-Cu(II)-Hs was investigated by batch and flow method. Antimicrobial activities of CX-Cu(II)-Hs were tested against Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa and Escherichia coli and it showed prolonged activity compared to that of free Hs.

Anti-Bacterial Agents↗
PubMed1997

Tunnel expansion following anterior cruciate ligament reconstruction: a comparison of hamstring and patellar tendon autografts.

Thirty patients having had anterior cruciate ligament (ACL) reconstruction with bone-patellar tendon-bone (BPTB) autograft and thirty patients having had ACL reconstruction with hamstring (HS) autograft were enrolled. All procedures were performed using an endoscopic technique with identical postoperative rehabilitation, such that the only variable was the type of graft and its fixation. Lateral and 45 degrees posteroanterior (PA) weightbearing radiographs were performed in each patient at 6-12 (mean 9) months postoperatively in the HS group and 9-22 (mean 13) months postoperatively in the PT group. The sclerotic margins of the tunnel were measured at the widest dimension of the tunnel by a single observer and were compared with the initially drilled tunnel size after correction for radiographic magnification. For the BPTB group, all bone plugs appeared to be incorporated radiographically. On the femoral side, the bone plug was incorporated at the roof of the intercondylar notch, such that no tunnel measurement could be made. Well-defined sclerotic margins were always present at the tibial and femoral tunnels for the HS group and at the tibial tunnel for the BPTB group. The mean percentage increase in tunnel size in the PA view was 9.7%+/-14.7% for the BPTB tibial tunnel, 20.9%+/-13.4% for the HS tibial tunnel, and 30.2%+/-17.2% for the HS femoral tunnel. The mean percentage increase in tunnel size in the lateral view was 14.4%+/-16.1% for the BPTB tibial tunnel, 25.5%+/-16.7% for the HS tibial tunnel, and 28.1%+/-14.7% for the HS femoral tunnel. The difference in HS and BPTB tibial tunnel expansion on both the PA and lateral views was statistically significant (P = 0.003 and P = 0.01, respectively). Inter-observer variability was excellent with an intra-class correlation coefficient of 0.92. Tunnel expansion was significantly greater following ACL reconstruction using HS autografts than in those using BPTB autografts. The points of fixation for the HS grafts are at a greater distance from the normal insertion site and biomechanical point of action of the ACL than the points of fixation for BPTB grafts. We believe that this greater distance creates a potentially larger force moment during graft cycling which may lead to greater expansion of bone tunnels.

Adolescent↗
PubMed2003

Characterisation of structure and aggregation processes of aquatic humic substances using small-angle scattering and X-ray microscopy.

Aquatic humic substances (HS), an important part of the dissolved organic carbon in freshwater systems, are polyfunctional natural compounds with polydisperse structure showing strong aggregation/coagulation behaviour at high HS concentrations and in the presence of metal ions. In this study, small-angle neutron scattering (SANS), small-angle X-ray scattering (SAXS) and X-ray microscopy (XRM) were applied to characterise the structure and aggregation processes of HS in solution. In SAXS and XRM the high brilliant synchrotron radiation was used as X-ray source. Applying small-angle scattering, information about the size distribution and shape of aquatic HS was obtained. Spherical HS units were found which were stable in a wide concentration range in a kind of "monomeric" state almost independent of pH and ionic strength. At higher concentrations they formed chain-like agglomerates or disordered HS structures. In studies on the coagulation behaviour of HS after addition of copper ions, a linear relationship between Cu(2+) concentration and the formation of large disordered HS-Cu(2+) agglomerates was obtained. By using X-ray microscopy, single "huge" particles were found in older solutions and in solutions with high HS concentrations. Over a threshold Cu(2+) concentration of approx. 300 mg/L, the formation of an extensive HS-Cu(2+) network structure was observed within a few minutes. The presented structures show the ability of the methods used to characterise processes between diluted phase and suspended matter, which play an important role particularly in the region of phase interfaces.

Journal Article↗
PubMed2006

Anticoagulant heparan sulfate: structural specificity and biosynthesis.

Heparan sulfate (HS) is present on the surface of endothelial and surrounding tissues in large quantities. It plays important roles in regulating numerous functions of the blood vessel wall, including blood coagulation, inflammation response, and cell differentiation. HS is a highly sulfated polysaccharide containing glucosamine and glucuronic/iduronic acid repeating disaccharide units. The unique sulfated saccharide sequences of HS determine its specific functions. Heparin, an analog of HS, is the most commonly used anticoagulant drug. Because of its wide range of biological functions, HS has become an interesting molecule to biochemists, medicinal chemists, and developmental biologists. In this review, we summarize recent progress toward understanding the interaction between HS and blood-coagulating factors, the biosynthesis of anticoagulant HS and the mechanism of action of HS biosynthetic enzymes. Furthermore, knowledge of the biosynthesis of HS facilitates the development of novel enzymatic approaches to synthesize HS from bacterial capsular polysaccharides and to produce polysaccharide end products with high specificity for the biological target. These advancements provide the foundation for the development of polysaccharide-based therapeutic agents.

Anticoagulants↗
PubMed2002

Requirements for NF-kappaB activation in hemorrhagic shock.

The activation of nuclear factor (NF)-kappaB contributes to the dysfunctional inflammatory response accompanying resuscitation from hemorrhagic shock (HS), in part through induction of pro-inflammatory cytokines including granulocyte colony-stimulating factor (G-CSF) and interleukin (IL)-6. In previous studies, we demonstrated that G-CSF and IL-6 up-regulation required both the ischemic and resuscitation phases of HS. In this study, we examined whether or not both phases of HS were required for NF-kappaB activation and the kinetics of its activation. Sprague-Dawley rats were subjected to unresuscitated HS with increasing duration of the ischemic phase [compensated HS, 0% shed blood return (SBR); decompensated HS, 35% SBR; and irreversible HS, 70% SBR) or HS (compensated or decompensated)] followed by resuscitation. NF-kappaB activity did not increase in any of the unresuscitated groups compared with sham controls. In contrast, resuscitation as early as 1 h following HS resulted in increased NF-kappaB activity compared with both the unresuscitated shock group and sham controls; NF-kappaB activation persisted for 8 h. Thus, NF-kappaB activation requires both phases of HS, occurs rapidly following resuscitation, and persists throughout the early stages of dysfunctional inflammation following resuscitation.

Analysis of Variance↗
PubMed1985

Heat-shock-induced enhanced reactivation of UV-irradiated Herpesvirus.

The objective of this study was to compare the ability of heat shock (HS) with that of another type of cellular stress, UV irradiation, to cause the induction of enhanced viral reactivation, a process that may represent an SOS-type repair process in mammalian cells. Studies performed to evaluate the effect of HS on growth of Vero cells revealed that HS at 45 degrees C for 45 min caused inhibition of cell growth similar to that caused by UV irradiation at 12 J/m2, but this inhibition was not observed at HS treatment for 5-15 min, or at a UV fluence of 2 J/m2. Enhanced reactivation of UV-irradiated Herpesvirus was observed in cells which had been pretreated by HS for greater than 30 min or UV at 12 J/m2. The synthesis of new proteins following HS for 15 and 45 min and UV at 12 J/m2 was examined by [35S]methionine-labeling experiments. The new synthesis of two HS proteins with molecular weights of 46 000 and 78 000 was induced by both levels of HS, but to a much greater extent at the high dose. These proteins were not detected in response to UV irradiation. These results indicate that, like UV irradiation, HS at levels inhibitory to cell growth induced enhanced viral reactivation in Vero cells. The results also suggest that at least two proteins in the HS protein family are not necessary for this response to occur.

Animals↗