Biomedical subjects

G Wang

Publications and source records attributed to G Wang.

At least 523 records · Page 29Linked to original sources

PubMed1997

Expression of HGF and cMet in the developing and adult brain.

Hepatocyte growth factor (HGF) was recently recognized as a potential neurotrophic factor in the developing brain. We studied expression of HGF and its receptor using Northern blot analysis and in situ hybridization for mRNA and double immunofluorescent laser confocal microscopy. HGF and cMet messages were abundant in the hippocampus of both human and rat brains. In this region, both messages were localized in the neuronal layer. Segregation of HGF predominantly in the hippocampal CA3-4 and cMet in CA1 supports the hypothesis that HGF may mediate important neurotrophic functions in both developing and adult brains.

Animals↗

PubMed1997

Efficacy of danazol in a patient with congenital protein-S deficiency: paradoxical evidence for decreased platelet activation with increased thrombin generation.

Danazol, a synthetic attenuated anabolic steroid, has been administered for 36 months to a 32 year old male with hereditary Protein S (PS) deficiency who had become non-compliant for warfarin therapy. The patient has an eleven year history of venous thrombosis. Since danazol therapy was initiated, the patient has not experienced a thrombotic event or adverse side-effects. Levels of PS, other inhibitors, fibrinolytic components, and markers for thrombin and platelet activation were measured prior and subsequent to therapy. Following danazol administration, marked and sustained increases were noted in Free Protein S, Antithrombin, and Protein C. Platelet CD62 (P-selectin) positivity which was elevated before therapy, decreased to assay threshold limits within five weeks. Both Prothrombin Fragment 1.2 and thrombin-antithrombin complexes were elevated post danazol therapy indicating continued clearance of generated thrombin. These data suggest that the protective effect provided by danazol in this patient with hereditary PS deficiency, may in large part be due to suppression of platelet activation by thrombin inhibition than simply through elevation of PS.

Adult↗

PubMed1997

Influence of the positions of cis double bonds in the sn-2-acyl chain of phosphatidylethanolamine on the bilayer's melting behavior.

In an attempt to examine the effects of different numbers and positions of cis double bonds in the sn-2-acyl chain of phosphatidylethanolamine (PE) on the bilayer's melting behavior, 21 molecular species of PE were first semisynthesized, and their Tm and DeltaH values were subsequently determined by high resolution differential scanning calorimetry. In the plot of Tm versus the number of the cis double bond, some characteristic profiles were observed for the various series of PEs. For instance, if the cis double bond was first introduced into the sn-2-acyl chain of C(20):C(20)PE at the Delta5-position, the Tm was observed to reduce drastically. Subsequent stepwise additions of up to five cis double bonds at the methylene-interrupted positions toward the methyl end resulted in a progressive yet smaller decrease in Tm. If, on the other hand, the cis double bonds were introduced sequentially at the Delta11-, Delta11,14-, and Delta11,14,17-positions along the sn-2-acyl chain of C(20):C(20)PE, the Tm profile in the Tm versus the number of the cis double bond showed a down-and-up trend. Most interestingly, for positional isomers of C(20):C(20:3Delta5,8,11)PE, C(20):C(20:3Delta8,11,14)PE, and C(20):C(20:3Delta11,14,17)PE, an inverted bell-shaped Tm profile was detected in the plot of Tm against the position of the omega-carbon for these isomers. Similar Tm profiles were also observed for C(18):C(20)PE, C(20):C(18)PE, and their unsaturated derivatives. This work thus demonstrated that both the positions and the numbers of cis double bonds in the sn-2 acyl chain could exert noticeable influence on the gel-to-liquid crystalline phase transition behavior of the lipid bilayer. Finally, a molecular model was presented, with which the behavior of the gel-to-liquid crystalline phase transition observed for lipid bilayers composed of various sn-1-saturated/sn-2-unsaturated lipids can be rationalized.

Acylation↗

PubMed1997

Probing energy coupling in the yeast plasma membrane H+-ATPase with acetyl phosphate.

The energy-rich compound acetyl phosphate (ACP) was examined as a substrate for energy-linked reactions by the yeast plasma membrane H+-ATPase. The hydrolysis of ACP was sensitive to inhibition by vanadate with an IC50 approximately 1 microM, which is comparable to the level obtained in the presence of ATP. A Km of 8.29 +/- 0.65 mM for the hydrolysis of ACP was approximately 10-fold higher than that obtained for ATP, while Vmax values of 8.66 +/- 0.29 and 7.23 +/- 0.34 micromol Pi mg(-1) min(-1) were obtained with ATP and ACP, respectively. ACP formed a phosphorylated intermediate that was efficiently chased with hydroxylamine. Both ACP and ATP effectively protected the enzyme from trypsin-induced inactivation and formed identical tryptic digestion patterns, suggesting that ACP mimics the formation of conformational intermediates induced by ATP. However, unlike ATP, ACP was unable to drive proton transport by H+-ATPase. In addition, a pma1-S368F mutant enzyme that is highly insensitive to inhibition by vanadate in the presence of ATP was largely sensitive to vanadate in the presence of ACP. These results are interpreted in terms of a reverse, short-circuit pathway of the normal P-type ATPase kinetic pathway, in which the formation of E2P by-passes the E1P high-energy intermediate. In this pathway, ACP favors the formation of an E2P conformational state, which can interact with classical inhibitors like vanadate, but possesses insufficient free energy to drive proton transport by the H+-ATPase.

Adenosine Triphosphate↗

PubMed1997

Replication of M13 single-stranded viral DNA bearing single site-specific adducts by escherichia coli cell extracts: differential efficiency of translesion DNA synthesis for SOS-dependent and SOS-independent lesions.

In order to characterize mutagenic translesion DNA synthesis in UVM-induced Escherichia coli, we have developed a high-resolution DNA replication system based on E. coli cell extracts and M13 genomic DNA templates bearing mutagenic lesions. The assay is based on the conversion of M13 viral single-stranded DNA (ssDNA) bearing a single site-specific DNA lesion to the double-stranded replicative form (RF) DNA, and permits one to quantitatively measure the efficiency of translesion synthesis. Our data indicate that DNA replication is most strongly inhibited by an abasic site, a classic SOS-dependent noninstructive lesion. In contrast, the efficiency of translesion synthesis across SOS-independent lesions such as O6-methylguanine and DNA uracil is around 90%, very close to the values obtained for control DNA templates. The efficiency of translesion synthesis across 3,N4-ethenocytosine and 1, N6-ethenoadenine is around 20%, a value that is similar to the in vivo efficiency deduced from the effect of the lesions on the survival of transfected M13 ssDNA. Neither DNA polymerase I nor polymerase II appears to be required for the observed translesion DNA synthesis because essentially similar results are obtained with extracts from polA- or polB-defective cells. The close parallels in the efficiency of translesion DNA synthesis in vitro and in vivo for the five site-specific lesions included in this study suggest that the assay may be suitable for modeling mutagenesis in an accessible in vitro environment.

Bacteriophage M13↗

PubMed1997

Role of Q-type Ca2+ channels in vasopressin secretion from neurohypophysial terminals of the rat.

1. The nerve endings of rat neurohypophyses were acutely dissociated and a combination of pharmacological, biophysical and biochemical techniques was used to determine which classes of Ca2+ channels on these central nervous system (CNS) terminals contribute functionally to arginine vasopressin (AVP) and oxytocin (OT) secretion. 2. Purified neurohypophysial plasma membranes not only had a single high-affinity binding site for the N-channel-specific omega-conopeptide MVIIA, but also a distinct high-affinity site for another omega-conopeptide (MVIIC), which affects both N- and P/Q-channels. 3. Neurohypophysial terminals exhibited, besides L- and N-type currents, another component of the Ca2+ current that was only blocked by low concentrations of MVIIC or by high concentrations of omega-AgaIVA, a P/Q-channel-selective spider toxin. 4. This Ca2+ current component had pharmacological and biophysical properties similar to those described for the fast-inactivating form of the P/Q-channel class, suggesting that in the neurohypophysial terminals this current is mediated by a 'Q'-type channel. 5. Pharmacological additivity studies showed that this Q-component contributed to rises in intraterminal Ca2+ concentration ([Ca2+]i) in only half of the terminals tested. 6. Furthermore, the non-L- and non-N-component of Ca(2+)-dependent AVP release, but not OT release, was effectively abolished by the same blockers of Q-type current. 7. Thus Q-channels are present on a subset of the neurohypophysial terminals where, in combination with N- and L-channels, they control AVP but not OT peptide neurosecretion.

Animals↗

PubMed1997

A case-control study of diet and lung cancer in northeast China.

A case-control study involving interviews with 227 lung-cancer cases and 227 matched hospital controls was conducted in Heilongjiang Province in northeast China to examine the influence of dietary factors on the risk of developing lung cancer. Lung-cancer cases were all incident cases judged to be suitable candidates for tumor removal by surgery. Controls were selected among hospitalized patients with non-neoplastic and non-lung disease. The overall male lung-cancer risks associated with cigarette smoking were similar to those reported in other Chinese studies but quite low compared to risks in Western countries. However, the subjects in this study were relatively young (average age 53.2), had started to smoke on average at a relatively old age (21.3 years), and only smoked an average of 18.7 cigarettes per day. Lung-cancer risk was not strongly associated with any of the nutrients examined, when all cases were compared to all controls. However, the data were suggestive of differences in the relationship of diet to risk among smokers and non-smokers. Cautious interpretation is required because of the wide confidence intervals due to limited sample size. Among the smokers, only higher beta-carotene was associated with estimates suggesting a lowered risk. Among non-smokers, the evidence suggested that increased vegetable consumption might reduce risk, consumption of any fruit might reduce risk but beta-carotene was unrelated to risk. The differences observed in the relationship of diet to lung-cancer risk between Chinese smokers and non-smokers warrant further study.

Case-Control Studies↗

PubMed1997

Alveolar macrophages inhibit retrovirus-mediated gene transfer to airway epithelia.

Gene transfer with integrating vectors such as recombinant retrovirus has the potential to correct inherited lung diseases permanently. As a gene therapy target, the pulmonary epithelium presents several challenges to vector delivery in vivo. Many of the host defenses that have evolved to prevent infection from inhaled bacteria or viruses represent potential barriers to gene transfer to the lung. We performed in vitro studies to determine whether two components of the innate immune system of the lung, airway surface fluid and alveolar macrophages, inhibit retroviral gene transfer to airway epithelia. Human alveolar macrophages obtained by bronchoalveolar lavage from normal subjects were left untreated or activated with lipopolysaccharide (LPS) for 3 hr in the presence of subconfluent human bronchial epithelial cells (HBE); than 4 x 10(5) cfu DA-luciferase retrovirus was added. Three days after infection, luciferase activity was measured in cell lysates. When the epithelial cells were co-cultured with LPS-activated macrophages, retroviral gene transfer to HBE cells was reduced by approximately 60%. Nonactivated macrophages decreased the transfection to approximately 55% of control values. In control experiments with either activated or inactivated macrophages but without epithelia, no luciferase activity was detected, suggesting that terminally differentiated alveolar macrophages are not infected by the recombinant retrovirus. Pretreatment of alveolar macrophages with dexamethasone restored gene transfer to approximately 60% of control values. In contrast, incubation of retrovirus with airway surface fluid had no inhibitory effect on gene transfer. These experiments document that AM inhibit retrovirus-mediated gene transfer to airway epithelia in vitro, and may represent a barrier to retroviral gene transfer in vivo. These barriers may be overcome, at least partially, with pharmacological agents.

Antineoplastic Agents, Hormonal↗

PubMed1997

Muscle sensory innervation patterns in embryonic chick hindlimbs following dorsal root ganglion reversal.

Previous studies suggest that sensory innervation of muscles is patterned by motor innervation. Muscle afferent projections mirror motor projections after various experimental manipulations and muscle afferents fail to project to muscle in the absence of motoneurons. It is not known, however, whether muscle afferents are specified with respect to the corresponding motoneurons or target muscles. To test this possibility we rotated three to four segments of neural crest in St. 15-17 chick embryos, leaving motoneurons intact, to reverse the rostrocaudal order of dorsal root ganglia (DRGs) T7/LS1-LS3. This caused sensory neurons derived from one segmental level to grow into the limb with motor axons from a different level. The resulting innervation patterns were assessed at St. 28-37 by injecting DiI and DiA into the sartorius and femorotibialis muscles or into the spinal cord and DRG. DiI labeling of crest prior to rotation showed that DRGs in the operated region were derived primarily from rotated cells. Muscle afferents from rotated DRGs grew to muscles in accord with their new rostrocaudal position, together with "inappropriate" motor axons from the same segmental level. The segmental distribution of sensory neurons innervating each muscle was more widespread in embryos operated at older than at younger stages. In contrast, sensory axons projected to the appropriate muscles in accord with their embryonic origin when segments of the whole neural tube, including motoneurons, were rotated, as reported previously. Thus, sensory neurons do not appear to be selectively matched with motoneurons or target muscles at stages when the corresponding motoneurons have clear identities.

Animals↗

PubMed1997

Mutations of O6-methylguanine-DNA methyltransferase gene in esophageal cancer tissues from Northern China.

Epidemiologic studies have implicated the involvement of environmental factors in the etiology of esophageal cancer (EC). Our previous data have indicated that EC patients and their blood relatives show genomic instability and are deficient in repair of DNA damage induced by N-nitroso-compounds and related genotoxic agents. Thus, exposure to high levels of N-alkylnitrosamines, which are known animal carcinogens and which induce alkyl adducts in DNA, may be causally linked to EC. Among the alkyl adducts, O6-alkylguanine was shown to be the critical one related to carcinogenic lesions; its repair varies widely in a tissue-specific fashion. O6-methylguanine-DNA methyltransferase (MGMT) is responsible for its repair. Hence, inactivating mutations in this protein would impair the efficiency of the repair process. To screen for possible mutations in the MGMT polypeptide in EC patients, we analyzed a highly conserved region of the MGMT gene in 40 EC tissues and lymphocytes of 6 high-risk EC family members from high EC areas of Northern China by polymerase chain reaction single-strand conformation polymorphism and by direct sequencing of PCR products. Ten base substitutions (point mutations) within 8 codons of 7 EC samples were identified. However, no germline mutation was found in the high EC families studied so far. Concurrent study in 30 pairs of fresh EC tissues and their adjacent normal mucosa by Southern blot and Western blot analyses showed deletion of the MGMT gene in 2 samples. Thus, the high frequency of mutations (7/40) and deletions (2/30) of the MGMT gene may be partially responsible for the overall high mutation rate observed in EC tissues.

Base Sequence↗

PubMed1997

The structure of cucumber mosaic virus: cryoelectron microscopy, X-ray crystallography, and sequence analysis.

The three-dimensional structure of cucumber mosaic virus (CMV) was analyzed at 23 A resolution by cryoelectron microscopy and image reconstruction, demonstrating structural similarity to cowpea chlorotic mottle virus (CCMV), another member of the Bromoviridae family. The CMV structure was determined at 8 A resolution by X-ray crystallography with phases determined by single isomorphous replacement and refined by fivefold noncrystallographic symmetry averaging. The X-ray structure agreed with the electron microscopy reconstruction; the electron density is consistent with beta-barrel subunits arranged with T = 3 quasi-symmetry in an orientation similar to that observed in CCMV. Strong density surrounding the icosahedral threefold axes (quasi sixfold axes in the T = 3 particle) between 80 and 100 A from the particle center formed a cylinder of radius 11 A, similar to the density observed in the same region of CCMV. This density corresponds to the beta-annulus of CCMV, which differentiates hexamers from pentamers and determines the formation of the T = 3 particles. The CMV and CCMV amino acid sequences were aligned, providing information (based on the CCMV atomic model) about the probable distribution of residues in the three-dimensional structure of CMV.

Amino Acid Sequence↗

PubMed1997

Machado-Joseph disease gene product identified in lymphocytes and brain.

Machado-Joseph disease (MJD) is associated with the expansion of an unstable CAG repeat. The existence of an abnormal gene product in MJD was previously suggested with the expanded polyglutamine stretch-specific antibody. However, the product of the normal allele has not previously been identified. We generated monoclonal antibodies against the fusion protein (codon 225-310) of the MJD gene product and then identified the MJD1 gene product in normal lymphoblastoid cells as a approximately 50-kDa protein by immunoblot analysis. The electrophoretic mobility differences among the normal allele products corresponds to the molecular size difference produced by the polyglutamine stretch and the polymorphism at the C-terminus. Moreover, abnormal immunoreactive bands which were larger than the normal ones were found as a approximately 60-kDa protein exclusively in the MJD samples. The cytoplasm and the nuclei of neurons and glial cells were stained by these antibodies with immunocytochemistry. As in other CAG repeat diseases, the abnormal and normal allele products were almost equally expressed in lymphoblastoid cells and the brain of MJD patients.

Alleles↗

PubMed1997

Folate deficiency causes uracil misincorporation into human DNA and chromosome breakage: implications for cancer and neuronal damage.

Folate deficiency causes massive incorporation of uracil into human DNA (4 million per cell) and chromosome breaks. The likely mechanism is the deficient methylation of dUMP to dTMP and subsequent incorporation of uracil into DNA by DNA polymerase. During repair of uracil in DNA, transient nicks are formed; two opposing nicks could lead to chromosome breaks. Both high DNA uracil levels and elevated micronucleus frequency (a measure of chromosome breaks) are reversed by folate administration. A significant proportion of the U.S. population has low folate levels, in the range associated with elevated uracil misincorporation and chromosome breaks. Such breaks could contribute to the increased risk of cancer and cognitive defects associated with folate deficiency in humans.

Chromosome Aberrations↗

PubMed1997

The effect of intravenous administration of a chimeric anti-IgE antibody on serum IgE levels in atopic subjects: efficacy, safety, and pharmacokinetics.

CGP 51901 is a non-anaphylactogenic mouse/human chimeric anti-human IgE antibody that binds to free IgE and surface IgE of IgE-expressing B cells but not to IgE bound to high affinity IgE receptors (Fc epsilonR1) on mast cells and basophils or low affinity IgE receptors (Fc epsilonR2) on other cells. A phase 1 double-blind, placebo-controlled, single dose study with doses of 3, 10, 30, and 100 mg of CGP 51901 was conducted in 33 pollen-sensitive subjects who had raised levels of serum IgE and received either intravenous CGP 51901 or placebo. The administration of CGP 51901 was well tolerated and resulted in a decrease of serum free IgE levels in a dose-dependent manner, with suppression after 100 mg of CGP 51901 reaching > 96%. Time of recovery to 50% of baseline IgE correlated with the dose of administered antibody and ranged from a mean of 1.3 d for the 3 mg to 39 d for the 100 mg dose. Total IgE, comprised of free and complexed IgE, increased as stored and newly synthesized IgE bound to CGP 51901. Complexed IgE was eliminated at a rate comparable with the terminal half-life of free CGP 51901 (11-13 d at all doses). Only one subject showed a weak antibody response against CGP 51901. We conclude that the use of anti-human IgE antibody is safe and effective in reducing serum IgE levels in atopic individuals and provides a potential therapeutic approach to the treatment of atopic diseases.

Adolescent↗

PubMed1997

Aldose reductase and IGF-I gene expression in aortic and arteriolar smooth muscle during hypo- and hyperinsulinemic diabetes.

Two genes whose expression is likely to be altered during diabetes mellitus are aldose reductase (AD) and insulin-like growth factor-I (IGF-I). We proposed that gene expression of AD is increased in vascular smooth muscle during diabetes mellitus due to hyperglycemia, while IGF-I expression is decreased in insulin-deficient diabetes and elevated in insulin-resistant diabetes. The mRNA for both was measured in the renal glomerulus, in the vascular smooth muscle of large arterioles from the brain, kidney, and small intestine, and in the aorta of hypoinsulinemic streptozotocin (STZ)-treated rats and hyperinsulinemic Zucker diabetic fatty (ZDF) rats. Quantitative in situ hybridization was used to determine variations in expression. Expression of the AD gene was unchanged in STZ and ZDF rats, except for a decrease of about 50% in glomeruli and renal smooth muscle of STZ diabetic rats. Expression of IGF-I generally decreased in vascular smooth muscle of insulin-depleted STZ diabetic rats, but was normal in hyperinsulinemic ZDF rats. The data indicate that decreased expression of the AD gene is a specific problem in renal vascular smooth muscle and glomeruli in the insulin-depleted STZ model of diabetes. The expression of the IGF-I gene in vascular muscle was decreased in hypoinsulinemic diabetic animals, but did not increase in hyperinsulinemic diabetic rats.

Aldehyde Reductase↗

PubMed1997

Expression of monocyte chemoattractant protein-1 in monocytes and effects of native and oxidized very low density lipoproteins.

Monocyte chemoattractant protein-1 (MCP-1), a potent chemoattractant, is thought to play an important role in migration of monocytes into atherosclerotic lesions. The present study was designed to investigate the capacity of human peripheral blood monocytes to express MCP-1 and effects of native very low density lipoprotein (VLDL) and oxidized VLDL (OX-VLDL) on the expression. The total RNA was extracted from cultured monocytes, which were exposed to VLDL and OX-VLDL, and the media conditioned by monocytes were collected. MCP-1 mRNA expression was examined by Northern blot analysis. MCP-1 protein in conditioned media was determined by using sandwich ELISA. The results showed that monocytes can express MCP-1 after a 24 h incubation at 37 degrees C, and the expression was markedly increased by a exposure to OX-VLDL, whereas the expression was slightly increased when exposed to VLDL. It suggests that the capacity of monocytes to produce MCP-1 that recruits and activates circulating monocytes may be of considerable importance in atherogenesis, and oxidation of VLDL enhances its potential to promote atherogenesis.

Arteriosclerosis↗

PubMed1997

High plasma levels of the soluble form of CD30 activation molecule reflect disease activity in patients with Wegener's granulomatosis.

PURPOSE: To determine the plasma levels of soluble CD30 (sCD30) in Wegener's granulomatosis (WG) patients, and to investigate the possible correlation of sCD30 with disease extent and activity. PATIENTS AND METHODS: sCD30 was determined by radioimmunoassay in 57 WG patients, 25 patients with rheumatoid arthritis (RA), 23 patients with bacterial infections and 21 healthy controls (HC). The extent and activity of WG disease were assayed according to disease extent index (DEI) and standard laboratory parameters. RESULTS: Plasma sCD30 levels in generalized WG (22.5 +/- 1.5 U/mL), but not in initial phase WG (12.1 +/- 4.0 U/mL), were significantly increased compared with HC (8.8 +/- 0.9 U/mL, P < 0.0001). Furthermore, of 11 generalized WG patients who received long-term follow-up, sCD30 levels declined when the disease activity changed from active disease to remission (29.1 +/- 1.9 U/mL to 15.9 +/- 1.8 U/mL, P = 0.0001). Similar results were observed in the whole group of generalized WG, eg, sCD30 levels in active disease (29.4 +/- 1.4 U/mL) were significantly higher than in partial remission (17.9 +/- 1.9 U/mL, P < 0.001) and in complete remission (13.7 +/- 3.3 U/mL, P < 0.001). No significant difference was noted between complete remission and HC. In addition, sCD30 levels were correlated with other parameters of disease extent and activity such as DEI, plasma levels of sIL-2R, PR3-ANCA, ESR and CRP. The sCD30 levels were increased in RA patients compared with HC (15.2 +/- 2.1 U/mL, P < 0.05), but no correlation was found between disease activity parameters and sCD30 levels. In contrast, in patients with bacterial infections sCD30 levels (6.9 +/- 0.9 U/mL) were not significantly different compared with HC. CONCLUSION: Plasma levels of sCD30 are not only significantly increased but also correlate with disease extent and activity in generalized WG. These findings suggest that sCD30 can act as a useful marker for evaluation of disease extent and activity, and that generalized WG may be associated with Th2-type immune response.

Arthritis, Rheumatoid↗

PubMed1997

Influence of cis double bonds in the sn-2 acyl chain of phosphatidylethanolamine on the gel-to-liquid crystalline phase transition.

We have semisynthesized 19 species of mixed-chain phosphatidylethanolamines (PEs) in which the sn-1 acyl chain is derived from saturated fatty acids with varying chain lengths and the sn-2 acyl chain has different chain lengths but contains 0, 1, and 2 cis double bond(s). The gel-to-liquid crystalline phase transition temperatures (Tm) of lipid bilayers prepared from these 19 mixed-chain PEs were determined calorimetrically. When the Tm values are compared with those of saturated and monounsaturated counterparts, a common Tm profile is observed in the plot of Tm versus the number of cis double bonds. Specifically, a marked stepwise decrease in Tm is detected as the number of cis double bonds in the sn-2 acyl chain of the mixed-chain PE is successively increased from 0 to 1 and then to 2. The large Tm-lowering effect of the acyl chain unsaturation can be attributed to the increase in Gibbs free energy of the gel-state bilayer as a result of weaker lateral chain-chain interactions. In addition, we have applied molecular mechanics calculations to simulate the molecular structure of dienoic mixed-chain C(X):C(Y:2 delta n,n+3)PE in the gel-state bilayer, thus enabling the three independent structural parameters (N, delta C, and LS) to be calculated in terms of X, Y, and n, which are intrinsic quantities of C(X):C(Y:2 delta n,n+3)PE. When the Tm values and the corresponding N and delta C values of all dienoic mixed-chain PEs under study are first codified and then analyzed statistically by multiple regressions, the dependence of Tm on the structural parameters can be described quantitatively by a simple and general equation. The physical meaning and the usefulness of this simple and general equation are explained.

Calorimetry, Differential Scanning↗