[Femtosecond laser-assisted cataract surgery and conventional phacoemulsification cataract surgery in patients with lens subluxation]

PURPOSE

To analyze the results of femtosecond laser-assisted cataract surgery (FLACS) and conventional phacoemulsification cataract surgery (CPCS) in patients with 1-2 degree lens subluxation.

MATERIAL AND METHODS

The follow-up involved 86 patients (89 eyes). The 1^st group comprised 34 patients (35 eyes) that underwent FLACS; the 2^nd group included 52 patients (54 eyes) who underwent CPCS.

RESULTS

At day four of the follow-up central corneal thickness was significantly lower after FLACS (p_m-u=0.024), but the difference did not remain statistically reliable by 1.5 months after the surgery. At discharge day and 4 months after the surgery uncorrected visual acuity (UCVA) after FLACS reliably exceeded UCVA of the 2^nd group patients (p_m-u=0.00) with mean UCVA being 0.61±0.29 and 0.42±0.25 respectively. Internal higher order aberrations (HOA) in 5.0 mm zone in the 1^st group decreased by 4 times and amounted to 0.236±0.06 μm, in the 2^nd group increased by 4.1 times and was 4.606±8.16 μm; the difference between the groups was statistically significant (p_m-u<0.001). Mean endothelial cells density after FLACS was 2551.91±321.55 cells/mm², after CPCS - 2352.35±436.68 cells/mm² (p_m-u<0.005). Complications after FLACS included 2 cases (5.71%) of posterior capsular rupture and 1 case (2.8%) of post-op corneal edema; patients after CPCS had 6 (11.1%) and 12 (22.2%) complication cases respectively.

CONCLUSION

FLACS is the safer and more effective surgery choice for patients with 1-2 degree lens subluxation in comparison with CPCS; it decreases the risk of possible complications and provides faster postoperative rehabilitation.

[Comparison of clinical and functional results of conventional and femtosecond laser-assisted cataract phacoemulsification]

PURPOSE

To perform a comparative analysis of ultrasound and hydrodynamic parameters, and the outcomes of femtosecond laser-assisted cataract surgery (FLACS) and conventional phacoemulsification cataract surgery (CPCS).

MATERIAL AND METHODS

This prospective cohort study included 246 eyes. The first group consisted of 138 patients who underwent FLACS, second group - 108 patients after CPCS.

RESULTS

Total ultrasound time was 95.36±47.93 and 113.3±97.71 seconds (p=0.04) in the 1^st and the 2^nd groups, respectively. The duration of torsional ultrasound was 84.72±50.03 seconds in 1^st group (p=0.04) and 113.3±97.71 seconds in the 2^nd group (p=0.04). Aspiration time was 208.3±95.86 seconds in the 1^st group (p=0.04) and 258.43±158.81 seconds in the 2nd group (p=0.04). On the 3-4^th day after the surgery, uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) were significantly better in the 1^st group - 0.62±0.21 (LogMAR 0.20±0.19) and 0.53±0.15 (LogMAR 0.30±0.21) (p=0.01), respectively, compared to the 2^nd group with UDVA of 0.75±0.18 (LogMAR 0.10±0.16) and CDVA of 0.69±0.19 (LogMAR 0.20±0.15) (p=0.04). Central corneal thickness (CCT) was 573.41±33.12 and 632.43±58.30 μm in the 1^st and 2^nd groups, respectively (p=0.020). At 1 month post-op there were no statistically significant differences in UDVA (p=0.17), CDVA (p=0.40) or CCT (p=0.50) between the groups.

CONCLUSION

Compared with CPCS, total ultrasound time (p=0.04), torsional ultrasound time (p=0.04) and aspiration time (p=0.04) were significantly lower in the FLACS group. CCT was significantly lower (p=0.02), while UDVA (p=0.04) and CDVA (p=0.01) were significantly higher in the FLACS group in the early post-operative period (3-4 days after surgery). There were no statistically significant differences in the parameters between the groups 1 month after the surgery.

[Splenic artery aneurysm masked by postcholecystectomy syndrome]

Visceral artery aneurysms appear to belong to uncommon and potentially lethal vascular diseases. They are usually revealed accidentally during an ultrasonographic examination, magnetic resonance imaging, or computed tomography. Described in the article is a clinical case report concerning a sacciform aneurysm of the splenic artery, detected in a 53-year-old woman presenting with postcholecystectomy syndrome and followed up for abdominalgia by therapeutists and gastroenterologists. Timely performed radiodiagnosis (including multispiral computed tomography and angiography of the abdominal vessels) made it possible not only to detect the aneurysm, having thus verified the volumetric formation previously found on ultrasonographic examination, but to take adequate measures aimed at preventing rupture of the aneurysm and consisting in endovascular occlusion of the aneurysmatic cavity with metal spirals. Lack of complete clarity in the understanding of the mechanisms of the origin of and no distinctly defined therapeutic-and-diagnostic algorithm for visceral artery aneurysms dictate the necessity to continue collecting and generalizing clinical case reports regarding this rarely encountered vascular pathology.

[The Dynamics of the Composition of mtDNA Haplotypes of the Ancient Population of the Altai Mountains from the Early Bronze Age (3rd Millennium BC) to the Iron Age (2nd-1st Centuries BC)]

The mtDNA polymorphism in representatives of various archaeological cultures of the Developed Bronze Age, Early Scythian, and Hunnish-Sarmatian periods was analyzed (N = 34). It detected the dominance of Western-Eurasian haplotypes (70.6%) in mtDNA samples from the representatives of the ancient population of the Early Bronze Age--Iron Age on the territory of Altai Mountains. Since the 8th to the 7th centuries BC, a sharp increase was revealed in the Eastern-Eurasian haplogroups A, D, C, andZ (43.75%) as compared to previous cultures (16.7%). The presence of haplotype 223-242-290-319 of haplogroup A8 in Dolgans, Itelmens, Evens, Koryaks, and Yakuts indicates the possible long-term presence of its carriers in areas inhabited by these populations. The prevalence of Western-Eurasian haplotypes is observed not only in the Altai Mountains but also in Central Asia (Kazakhstan) and the South of the Krasnoyarsk Krai. All of the three studied samples from the Western-Eurasian haplogroups were revealed to contain U, H, T, and HV. The ubiquitous presence of haplotypes of haplogroup H and some haplogroups of cluster U (U5al, U4, U2e, and K) in the vast territory from the Yenisei River basin to the Atlantic Ocean may indicate the direction of human settlement, which most likely occurred in the Paleolithic Period from Central Asia.

[Evaluation of association between 9 genetic polymorphism and myocardial infarction in the Siberian population]

to evaluate association between genetic polymorphism (SNPs) and myocardial infarction (identified in recent GWAS) as markers of high risk of myocardial infarction (MI) in Siberian population. Patients were divided into 2 groups - MI patients and control group (ratio 1:2) and presented the sapmle of population of Novosibirsk (9400 patients, 45-69 years) within international project HAPIEE (Health, Alcohol and Psychosocial factors In Eastern Europe). 200 patients with MI (129 men, 71 women) were included. Control group - individuals without MI (420) matched for age and sex. Genomic DNA was extracted from venous blood by phenol-chloroform extraction. Gene polymorphism of genes tested by real-time PCR according to protocol (probes TaqMan, Applied Biosystems, USA) with the use of ABI 7900HT. The following SNPs were studied: rs28711149, rs499818, rs619203, rs10757278 and rs1333049 (hr. 9), rs1376251, rs2549513, rs4804611, rs17465637. The association of SNP and MI was confirmed for 4 of 9 studied SNPs: rs1333049 (hr. 9), rs10757278 (hr. 9), rs499818 (hr. 6), rs619203 gene ROS1. Heart rate was associated with rs1333049 and rs10757278. Glucose level was associated with rs619203, rs28711149 and rs1376251. Total cholesterol and atherogenic index was associated with rs28711149. For the first time in Russian population the associations of GWAS with myocardial infarction SNPs was detected for rs619203, rs499818, rs1333049 and rs10757278. These genetic markers can be used for assessing the risk of myocardial infarction in Russian population.

[CCR5, CCR2, apoe, p53, ITGB3 and HFE gene polymorphism in Western Siberia long-livers]

In order to estimate the distribution of some polymorphisms for the CCR5, CCR2, apoE, p53, ITGB3, and HFE genes in Russian long-livers from Western Siberia, a sample of 271 individuals (range 90-105 years) was examined. It was demonstrated that carriage of the delta32 polymorphism for the CCR5 gene, V64/polymorphism for the CCR2 gene, e2/e3/e4 for the apoE gene, L33P for the ITGB3 gene, as well as H63D and S65C polymorphisms for the HFE gene does not influence on predisposition to the longevity; carriage of the 282 Y allele for the HFE gene negatively influences on the longevity; carriage of the heterozygous genotype for the R72P polymorphism for the p53 gene correlates with the longevity of elderly people.

Apolipoprotein E gene polymorphism in men with coronary atherosclerosis in Siberia

Polymorphism of coding fragment of APOE gene was analyzed in two groups of men. The main group consisted of 77 residents of the West Siberian region aged 45-65 years with coronary atherosclerosis (documented by coronary angiography) without acute coronary syndrome with stable effort angina, functional class II-IV. The reference group consisted of 350 residents of Novosibirsk, aged 45-69 years. Statistically significant associations between genotypes of APOE gene coding part polymorphism and some key lipid risk factors (blood total and LDL cholesterol, atherogenic index, etc.) for coronary atherosclerosis were found in male residents of the West Siberian region. Elevated total mean level of cholesterol was detected in male residents of Novosibirsk with the APOE genotypes containing ε4 allele.

[Association of Sp4 gene polymorphism with pathological tortuosity of internal carotid arteries]

Aim of the study was identification of genes and their polymorphisms associated with pathological tortuosity (PT) of internal carotid arteries (ICA) for elucidation of etiological causes of this anomaly taking into consideration its high prevalence and clinical significance. We invited for examination 61 families of children with previously diagnosed PT ICA and used color Doppler duplex scanning of brachiocephalic zone in examination of close relatives of a proband. Samples of venous blood were taken from a family member in whom PT ICA had been detected and the affected child. The group of patients for genotyping comprised 100 individuals with PT ICA. Control group (n=245) was formed from DNA bank on the basis of population approach. The following genetic methods of diagnosis were applied: clinico-genealogical, allele specific polymerase chain reaction, search in available data bases of PT ICA candidate genes and their polymorphisms. According to data of genealogy analysis in most cases inheritance of pathological sign of tortuous ICA was autosomal dominant (37.7%) or autosomal-recessive (39.3%). Association of A80807T polymorphism of the transcriptional factor Sp4 gene with PT ICA was established. Probability of PT ICA in A80807/A80807 homozygotes was 1.64 times higher than in carriers of 2 other genotypes (A80807/T80807 and T80807/T80807).

[APOE gene polimorphism and lithogenicity of the bile in the women with cholelithiasis]

AIM

to study the frequency of alleles and genotypes of APOE gene in women with gallstone disease (GSD), and also to research the association of the APOE gene polymorphism and bile lithogenicity indices.

MATERIALS AND THE METHODS

were investigated 104 women after cholecystectomy about verified cholesterol gallstones, and 176 women from the female Novosibirsk population, they were control group for the comparison of the frequency of APOE alleles and genotypes. Gallbladder bile (bile cholesterol, common bile acids) was investigated in women with GSD. Blood serum lipids and APOEgene polymorphism were studied in all women.

RESULTS

APOE gene polymorphism in the women with GSD did not differ from those registered in control group from women population. At the presence of APOE4 allele at the women with GSD the significant increase of gallbladder biliary cholesterol level was marked. In the women with GSD with various APOE genotypes average levels of blood serum lipids, common bile acids and bile cholesterol indices were similar.

[Sudden cardiac death and polymorphism of genes-candidates of cardiovascular diseases]

Aim of the study was to elucidate genetic markers associated with elevated risk of sudden cardiac death (SCD). We collected autopsy material during 1999 - 2001 in a process of forensic medical pathologo-anatomical examination of corpses of 182 men who had died suddenly in Octyabrsky district of Novosibirsk in the age of 25 - 64 years (mean age 53,6 +/- 7,9 years). We studied polymorphisms of the following genes: angiotensin converting enzyme - , glycoprotein IIb/IIIa - GPIIb/IIIa, alpha2b adrenoreceptor - ADRA2B, beta(1)-adrenoreceptor - ADRB1. Control comprised samples of population of men aged 25 - 35 and 55 - 64 years from the same district of Novosibirsk examined within framework of international WHO project MONICA. Comparison of frequencies of genotypes of polymorphism A1/A2 of GPIIb/IIIa gene in combined sample of population and group with SCD revealed in SCD group lowering of portion of A2/A2 homozygotes (5.0 and 1.2%, respectively, =0.029) and elevation of portion of A1/A2 heterozygotes (18.7 and 28.3%, respectively, =0.027). Odds ratio for a heterozygote to enter SCD group was 1.71 (95% confidence interval 1.0 to 2.77). Comparison of frequencies of genotypes and alleles of polymorphism A145G of ADRB1 gene in combined sample of population and group with SCD did not reveal any difference. Comparison of frequencies of polymorphism I/D of ACE gene in combined sample of population and group with SCD revealed significant lowering of frequencies of genotype I/I in SCD group (22.0 and 13.8%, respectively, p=0.033). There were no significant differences between SCD group and control in frequencies of studied polymorphism of alpha2b-adrenoreceptor gene.

[Genetics of atrial fibrillation]

We carried out examination of 103 probands with atrial fibrillation (AF) and 301 their 1st, 2nd, and 3rd degree relatives (main group). In addition we examined 82 probands without clinical electrocardiographic signs of heart disease and 163 their 1st and 2nd degree relatives (control group). We found accumulation of AF in families of probands with this pathology. Segregation analysis of idiopathic forms of AF allowed to reveal autosomal dominant type of inheritance of this pathology. Heterozygous variant of Ser49Gly of betai-adrenoreceptor gene can be considered as one of genetic predictors of development of how primary and secondary AF.

[The spectrum of mutations in the low-density lipoprotein receptor gene in the Russian population]

The spectrum of mutations in the low-density lipoprotein (LDL) receptor gene was studied in a sample of hypercholesterolemia patients of Caucasoid origin from the population of Russia. The examined patients were 45 to 49-years-old and had the highest level of total serum cholesterol in this age group. Seven previously non-described mutations have been revealed in exon 9 (R410G; M412V) and in exon 12 (Y/Y576; N/N591; L605V; L605R; A612G). Twelve previously described mutations have been identified in exons 2 (C/C27), 5 (C261F; E240X), 6 (E288K), 8 (A391T), 9 (E418G; L432R; D433E), 11 (G/G549; E558K; L/L568), and 12 (G592E). Only one of these mutations was previously described in Russia in a clinical sample of patients with familial hypercholesterolemia. The spectrum of LDL receptor gene mutations in the population sample of patients with hypercholesterolemia significantly differs from the mutation spectrum in patients with familial hypercholesterolemia (clinical samples). Sequencing of the LDL receptor gene is a highly efficient method for identifying the markers of hypercholesterolemia predisposition in a population.

Association of haplotypes of interleukin-10 gene with the risk of cancer

Polymorphisms of promotor region of IL-8, IL-10, and IL-12 genes were analyzed in cancer patients and subjects without history of cancer. The distribution of alleles of the analyzed polymorphisms in the control group coincided with that in other Caucasian populations. The incidences of three IL-10 gene polymorphisms (G-1082A, C-819T, and C-592A) significantly differed in controls and patients. Of 8 theoretically probable IL-10 gene haplotypes determined by these polymorphisms, 3 variants were revealed. Haplotype ACC was more incident in cancer patients, while ATA haplotype was rarer. The results are in line with the findings of other studies indicating the involvement of the immune system genes in the pathogenesis of cancer.

[Atherogenic oxidative and structural modification of low density lipoproteins in men with coronary atherosclerosis]

We studied parameters of structural and oxidative modification of low density lipoproteins (LDL) in 80 men aged 35 - 65 years with coronary atherosclerosis verified at coronary angiography in comparison with 80 men of the same age without ischemic heart disease. Biochemical studies included determination of parameters of lipid blood composition by enzymatic methods, subfractional LDL profile by electrophoresis in 2 - 16% gradient polyacrylamide gel, degree of oxidative modification of lipid (lipid peroxidation products) and apoprotein (carbonyl groups) components of LDL by fluorometric and spectrophotometric methods. In men with coronary atherosclerosis we revealed elevated level of small dense LDL and substantially oxidized lipid and apoprotein components of these particles. Independent association of structural and oxidative modification was shown.

[Deletional polymorphism of the 11th intron of the human c-fms gene: allele frequency in certain Russian populations and possible functional significance]

Analysis of deletion polymorphism of human c-fms gene intron 11 (approximately 425-bp deletion) is of particular interest because of the increased proportion of the deletion heterozygotes among the infants born from the parents, one of which lacks the deletion allele, and the other is heterozygous for the deletion. In this study, allele and haplotype frequencies of the polymorphism examined were assessed in a number of Caucasoid and Mongoloid populations of Russia. In all populations tested, relatively high prevalence of the deletion-bearing allele, ranging from 9.45% in ethnic Germans to 20.75% in Altaians, was detected. Russians and Kazakhs were characterized by intermediate frequencies of the rare allele, constituting in these populations 12.89 and 14.93%, respectively. Hardy-Weinberg expectations were met in all populations examined, pointing to a stable level of polymorphism at the c-fms intron 11. It was established by the context analysis of DNA of the deleted fragment along with the flanking sequences that this region contained a number of transcription factor motifs (Ets, SRF, and Myc), potentially capable of the regulation of the M-CFF-dependant c-fms transcription. The deletion breakpoint was localized within the CArG motif, which, together with the neighboring ets motif, form the potential CArG/ets composite element. It was suggested that allele lacking the fragment of intron 11 could be restricted in its ability to modulate the level of the c-fms transcription in response to the action of M-CSF. The data of molecular epidemiological survey serve as the indirect evidence favoring the suggestion on the possible functional value of this gene fragment. It was demonstrated that in the samples of acute bronchitis and trichomoniasis patients allelic and genotype frequencies were statistically significantly different from those in the population sample. In case of trichmoniasis, the frequency of rare allele was 2.4 times lower, and in case of acute bronchitis it was 2.1 times higher than in the control sample.

[Polymorphism of the HFE gene associated with hereditary hemochromatosis in populations of Russia]

Expression of hereditary hemochromatosis as well as predisposition to iron overload syndrome and sporadic porphyria cutanea tarda are currently believed to be associated with the inheritance of certain allelic variants of the HFE gene. Allele frequencies of the C282Y (845A) and H63D (187G) mutations in the HFE gene in human populations of different races are remarkably different, and the prevalence of the S65C (193T) mutation is still poorly studied. In the present study we estimated allele frequencies of HFE mutations in Russians and in a number of Siberian ethnic indigenous populations. In Russians, allele frequencies of the C282Y, H63D and S65C mutations were 3.7, 13.3 and 1.7%, respectively. These values were similar to those observed in populations of Europe. The C282Y mutation was not detected in the population samples of Siberian ethnic groups, including Mansis, Khantys (Finno-Ugric group), Altaians, and Nivkhs (Mongoloids), suggesting that the frequency of this allele in the populations examined was lower than 1%. The frequency of the C282Y allele in the Tuvinian and Chukchi samples (Mongoloids) constituted 0.45 and 0.8%, respectively. Furthermore, pedigree analysis of both Chukchi carriers discovered showed that some of their ancestors were from other ethnic groups. Low frequencies of this allelic variant is typical of many Eastern Asian populations, which are also characterized by rather low frequencies of the H63D variant. In contrast, in some ethnic groups of Western Siberia allelic frequency of the H63D mutation is rather high, constituting 8.7% in Altaians, 15.5% in Mansis, and 11.3% in Khantys. The frequency of this allele in Tuvinians, Nivkhs, and Chukchis constituted 5, 4.7, and 0.8%, respectively. These findings make it possible to estimate the proportion of individuals predisposed to iron overload syndrome in different Russian ethnic groups. The HFE allele frequency distribution patterns observed in the populations examined pointed to pre-Celtic appearance of the CY82 allele. It also provides elucidation of the evolutionary genetic relationships between Siberian ethnic groups and the contemporary populations of Eastern and Western Europe.

[Polymorphism of the gene of angiotensin-converting enzyme and apolipoprotein E gene in long-livers of Novosibirsk city]

The levels of polymorphism of genes of angiotensin converting enzyme (ACE) and apolipoprotein E (Apo E) were studied in elderly and long-living people in Novosibirsk. The results of the study in the investigated group (97 subjects) were compared with polymorphism of these genes in Novosibirsk population group aged 25-64 who were investigated in MONICA Project survey and had DNA data base formed. Frequency of D/D genotype among senile and long-living men was 5.9%. It is 5 times lower than in men 55-64 years of age (p = 0.04). Similar decrease of this gene frequency was also found in women of the same age. In men older than 83 years of age 4 times lowering of 3/4 genotype of Apo E gene and 2 times increasing of frequency of 2/3 genotype were revealed when comprising frequency of these genotypes in people of middle age. In subjects of senile age and long-livers of both sexes genotype 4/4 was not revealed. Lipid levels were more favorable in women with genotype 2/3 of Apo E gene (comparatively lower mean level of total cholesterol and higher level of HDL cholesterol) if compared with genotypes 3/3 and 3/4.

[Detection of two polymorphic sites in the human c-fms gene: allele frequency and genotype in some populations of Russia]

Two polymorphic sites were found in the human c-fms gene: one (G-->A) was in position 34,047 in the last intron, and the other (dinucleotide TC-->CA) was in positions 34,293 and 34,294 in the 3'-untranslated gene region, 34 bp downstream of the translation stop codon. The polymorphic dinucleotide appeared to be immediately upstream of an octamer showing 100% homology to cis element -CAAACTTC-, which is responsible for controlled instability of mRNAs of several genes. Based on these data, functional significance was assumed for this polymorphism of the c-fms gene. Allele frequencies were established for several populations. The mutant allele of the polymorphism located in the intron were detected only in one family of ethnic Germans from the Altaiskii krai. Polymorphism of the second site, which is in the 3'-untranslated region of the c-fms gene, was observed in all Caucasoid and Mongoloid populations examined. Frequency of the rare allele varied from 19.7-25% in Arctic Mongoloids to 31-42.6% in Central Asian Mongoloids and was similar in two Caucasoid populations (22.6% in ethnic Russians and 26.5% in ethnic Germans). The wide distribution of the mutant allele in human populations of the two races was considered indicative of an adaptive role of the polymorphism in providing a certain level of the gene product, a receptor, in certain cell processes.

[Prognostic factors influencing results of the surgical treatment of pancreatic cancer]

In patients with carcinoma of the pancreas 128 gastropancreatoduodenal resections (GPDR), 15 distal resections of the pancreas and 3 pancreatectomies were performed. After GPDR 5-year survival was 12%, the survival median was 24.3 months. Only one patient is living 6 years after left-sided resection and pancreatectomy. Long-term results of the operative treatment for carcinoma of the pancreas depended on the amount of regional metastases, degree of differentiation of the tumor, its size and invasion into the vessels. The long-term results were considerably worse if the tumor was localized in the uncinate process, body and tail of the pancreas. The 5-year survival was noted mainly in patients with the 0 and I stages of the disease. It shows the early diagnostics to be necessary.

Distribution of CCR5-delta 32 gene deletion across the Russian part of Eurasia

32-bp inactivating deletion in the beta-chemokine receptor 5 (CCR5) gene, common in Nothern European populations, is associated with reduced HIV-1 transmission risk and delayed disease progression. We have studied the deletion distribution in many populations in Eurasia by polymerase chain reaction analysis of 531 DNA samples representing West and East Siberian, Central Asian, and Far Eastern parts of Russia. An unusually high frequency (11.1%) of the deleted variant in natives of West Siberia, of Finno-Ugrian descent, was observed. Furthermore, the deletion was infrequent in indigenous populations of Central Asia, East Siberia, the Russian Far East, and Canada. We conclude that the delta(ccr5) distribution is limited primarily to Europeans and related western Siberian Finno-Ugrian populations, with a sharp negative gradient toward the east along the territory of Russian Asia.

[Crystalline and molecular structure of the K+-complex of meso-valinomycin, cyclo(-(D-Val-L-Hyi-L-Val-D-Hyi)3-).KAuCl4]

Crystal structure of the complex of meso-valinomycin with KAuCl4 (C60H102N6O18KAuCl4) was determined using direct X-ray diffraction analysis. The conformational state of the complex is similar to that determined earlier for free meso-valinomycin. Characteristic of it is the centrosymmetric bracelet shape stabilized by six intramolecular NH...OC hydrogen bonds of 4 --> 1 type. The K+ ion is located in an inner negatively charged octahedral cavity formed by six carbonyl oxygen atoms of ester groups. The observed differences in conformational angles of the complex and free are caused by readjustment of the geometry of the ion-binding cavity to the size of the ion bound during complexation.