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PubMed1985

Oligosaccharide structures of isolated human colonic mucin species.

Purified human colonic mucin contains six distinct components which may be separated by DEAE-cellulose chromatography. Past studies defined the structure of oligosaccharide side chains from the most abundant species III, IV, and V which elute at intermediate salt concentrations. In these studies the structures of oligosaccharide side chains liberated from the remaining early and late eluting species I, II, and VI were determined after isolation by sequential conventional and high performance liquid chromatography through combination of gas chromatography, methylation analysis, and sequential glycosidase digestion. Mucin species I, II, and VI contained a less varied array of discrete oligosaccharide structures than that observed in the major mucin components. Mucin species I and II contained five and 10 structures, respectively, which account for 68 and 71% of total oligosaccharide content in these fractions. The predominant oligosaccharides of mucin species I included three neutral structures: a disaccharide GlcNAc beta (1-3)GalNAc-ol, a trisaccharide Gal beta (1-4)GlcNAc beta (1-3)GalNAc-ol, and a tetrasaccharide GlcNAc beta (1-4)Gal beta (1-4)GlcNAc beta (1-3)GalNAc-ol as well as two acidic components representing the sialylated forms of two of these oligosaccharides. Mucin species II contained these same oligosaccharides as well as four additional acidic structures, notably a disaccharide Neu alpha (2-6)GalNAc-ol and a hexasaccharide Gal beta (1-4)GlcNAc beta (1-3)Gal beta (1-4)GlcNAc beta (1-3) (NeuAc alpha (2-6))-GalNAc-ol, not identified in any other mucin species. The late eluting mucin species VI contained at least five discrete neutral oligosaccharides and six major acidic structures. While the majority of these structures had been previously isolated from the earlier eluting mucin species IV and V, species VI also contained di- and trisialylated oligosaccharides not identified in other mucin species. In conjunction with earlier studies of the major mucin species III, IV, and V, these data define the range of oligosaccharide structures present in human colonic mucin. These studies demonstrate that human colonic mucin possesses species with characteristic and distinguishable combinations of oligosaccharides which reflect variations of common core structures.

Carbohydrate Sequence↗
PubMed1982

Management of duodenal diverticula.

Duodenal diverticula are not uncommon. Uncomplicated diverticula require no treatment. In the period 1970 to 1980, 104 patients with symptoms presented at the Vancouver General Hospital and the Swedish Hospital in Seattle. Of these, 26% presented with pain and 24% with anemia. Malabsorption and benign tumours were noted infrequently. Fifteen patients were treated surgically for pain, perforation, hemorrhage, tumour, blind loop syndrome and obstruction of the duodenum, biliary tract or pancreatic duct. Two patients died. The second part of the duodenum was involved in 82% and the third part in 10%. Anatomical variations are common in the area of the ampulla; these should be anticipated before operation. Surgical procedures in the area may be technically demanding and associated with high mortality and morbidity. The choice of procedure depends on the urgency and nature of the complication of the diverticulum. Endoscopic retrograde cholangiopancreatography can play a role in evaluating the possible significance of the diverticulum and the anatomy of the area. In some cases endoscopic sphincterotomy may be possible. In some situations diverticulectomy is contraindicated.

Adult↗
PubMed1993

Sonography of the thyroid and parathyroid.

Ultrasound is a primary imaging tool for thyroid and parathyroid localization. Classic thyroid and parathyroid tumors are easily distinguished by their sonographic appearance and location, but variations are common and complicate the distinction. Thus, biopsy under ultrasound guidance provides proof of the nature of the lesion. When parathyroid localization is problematic with ultrasound, magnetic resonance imaging is an excellent alternative.

Adenoma↗
PubMed1993

N-acetylation phenotyping with sulfamethazine in an Iranian population.

The acetylation polymorphism is one of the most common inherited variations in the biotransformation of drugs and chemicals. Its association with drug toxicity and increased risk of developing certain diseases and certain types of chemically induced cancers has made it one of the oldest and best studied examples of pharmacogenetic conditions. N-Acetylation of sulfamethazine was studied in 74 unrelated healthy Iranian volunteers. The frequency of slow acetylators, determined by using free and total plasma sulfamethazine concentrations, was 78.4%. The mean acetylation ratio was 19.48% for slow acetylators, and the frequency of the recessive allele controlling slow acetylation was found to be 0.88. This percentage is similar to that observed in various Arab countries and higher than that observed in Europeans.

Acetylation↗
PubMed1977

Associations in the hominoid facial skeleton.

A comparative study has been made of the correlations between numerous linear and angular dimensions of the facial skeleton of man and the three great apes. The Varimax (rotated orthogonal) factor analysis was found to be an essential aid in analysing the very large correlation matrices obtained. It indicated that three groups of association can be identified in the hominoid skull. The first reflects co-ordonated variation in total skull size; the second, co-ordinated variation within common anatomical regions; the third, co-ordination between the jaws and dentition. A broadly similar pattern was found in each group for all four genera. The principal contrasts between man, on the one hand, and the apes, on the other, were found in groups 1 and 2. The most prominent of these was a generally much tighter degree of association between the size and position of upper and lower jaws in the apes, and a consequently reduced tendency for disruption of the occlusal relationship of the teeth.

Animals↗
PubMed1979

Superficial anastomoses of blood vessels in the human heart.

We investigated superficial interarterial, intra-arterial, arterio-venous and veno-venous anastomoses in 100 hearts from men and women taken at random who died at 20-85 years of age. By means of careful dissection and injection into the blood vessels of a differently stained 12% solution of vinilit in acetone, we studied the number and localization of the anastomoses and their appearance. Interarterial anastomoses, i.e. anastomoses between the ramification of the left and the right coronary artery, were detected in 33 hearts. Intra-arterial anastomoses, i.e. anastomoses between the ramifications of one and the same artery, were seen in 5 hearts. Arterio-venous anastomoses were found in 39 hearts. Veno-venous anostomoses were found in 49 hearts. The veno-venous anastomoses display a great many variations, being commonly the regular finding in human veins.

Adult↗
PubMed1997

Clinical relevance of polymorphic markers of arterial thrombosis.

Case-control and cross-sectional studies show that some common molecular variations (polymorphisms) of genes coding for proteins involved in atherosclerosis and thrombosis are often present in subjects who have experienced cerebrovascular or cardiovascular events. The clinical impact of the majority of polymorphic markers is disputed by prospective reports. In contrast, their pathophysiological implications and their role in monitoring parameters that are difficult to be checked by alternative means, are documented by the large majority of the reports. From the evidence available, there may be suggestion for further impact of polymorphic markers in vascular medicine. To substantiate this, new prospective studies that include individuals from different geographical areas and that take into account the statistical power, the informativeness of the markers, the coexistance of established risk factors and the genetic background of the populations analyzed, are urgently needed.

Chromosome Mapping↗
PubMed2003

Seasonal variation in bacterial pathogens isolated from stool samples in Karachi, Pakistan.

OBJECTIVE: To determine the seasonal variation of the commonly isolated bacterial pathogens in stool samples. MATERIAL AND METHODS: A retrospective descriptive study was undertaken of all the stool samples submitted from within Karachi to the Aga Khan University Hospital Laboratory over a period of five years (January 1997- December 2001) in order to determine the commonly isolated bacterial pathogens and to predict their seasonal variation. RESULTS: A total of 16379 stool samples were included in this review. Bacterial isolates were found in 6670 stool samples (culture detection rate=40.7%). The mean age at the time of culture of each sub-group was < or = 1 year group (6.58 +/- 3.1 months), 1-5 years (2.13 +/- 0.94 years), 5-14 years (8.3 +/- 2.6 yrs) and adults (43.2 +/- 18.5 years). Male: Female ratio was 1.2:1. Vibrio cholera 01 Ogawa (32.8%), Campylobacter jejuni (17.3%), Enteropathogenic Escherichia coli (9.9%), Salmonella paratyphi b (6.6%) and Shigella flexneri (6.2%) were the most common organisms isolated. These organisms show a distinct seasonal variation with summer predilection. CONCLUSION: In contrast to the previous studies from South Asia, which have identified E. coil, followed by Vibrio cholerae as the most common enteric isolates, we found Vibrio cholera 01 Ogawa followed by Campylobacter jejuni as the most common enteric pathogens isolated in an urban setting. It is important to consider seasonal variation when empirically treating diarrheal diseases in our region.

Adolescent↗
PubMed1994

Ventricular beats induce variations in cycle length of rapid (type II) atrial flutter in humans. Evidence of leading circle reentry.

BACKGROUND: Slight variation in cycle lengths of common and rapid atrial flutter in humans is an established phenomenon, but its mechanisms have not been completely clarified. In a previous study, we demonstrated that in common atrial flutter the variations in atrial cycle length were due to atrial stretch affecting the revolution time of a reentrant circuit. In the present study, we investigate the nature of atrial cycle length variations in the rapid type of human atrial flutter. METHODS AND RESULTS: Atrial interval variations of 17 episodes of rapid atrial flutter in 14 patients were investigated by measuring the sequence of atrial intervals from intraesophageal or intra-atrial leads and the onset of QRS complexes from a surface lead (V1). To study whether interval variation in flutter cycle was related to ventricular activity, a phase plot was constructed in which the flutter cycle length was plotted against the time after the previous QRS complex. This showed that the interval fluctuations were strictly coupled to the moment of ventricular activation. After the onset of the QRS complex, the rapid atrial flutter interval gradually decreased by an average of 4.1% (P < .001) and reached a minimum value after 300 to 600 milliseconds. Thereafter, the intervals increased again until the next ventricular beat occurred. In 10 patients developing both common and rapid atrial flutter, two different phase relations were found. Whereas during common atrial flutter the atrial interval increased after the QRS complex, it decreased during rapid atrial flutter. In three patients, intra-atrial pressure was recorded together with the electrical activity during both common and rapid atrial flutter episodes. This showed that variations in atrial flutter cycle length were associated with the rise of atrial pressure during ventricular contraction. CONCLUSIONS: These findings indicate a role of contraction-excitation feedback caused by atrial stretch after a ventricular activation. The shortening of the atrial interval after the onset of the QRS complex as found in patients during rapid atrial flutter can be explained by stretch-induced shortening of atrial refractoriness and consequent shortening of the revolution time of a functionally determined intra-atrial circuit.

Aged↗
PubMed2005

Supportive evidence for an allelic association of the human KCNJ10 potassium channel gene with idiopathic generalized epilepsy.

PURPOSE: Quantitative trait loci (QTL) mapping in mice revealed a seizure-related QTL (Szs1), for which the inward-rectifying potassium channel Kcnj10 is the most compelling candidate gene. Association analysis of the human KCNJ10 gene identified a common KCNJ10 missense variation (Arg271Cys) that influences susceptibility to focal and generalized epilepsies. The present replication study tested the initial finding that the KCNJ10 Cys271 allele is associated with seizure resistance to common syndromes of idiopathic generalized epilepsy (IGE). METHODS: The study sample comprised 563 German IGE patients and 660 healthy population controls. To search for seizure type-specific effects, two IGE subgroups were formed, comprising 258 IGE patients with typical absences (IAE group) and 218 patients with juvenile myoclonic epilepsy (JME group). A TaqMan nuclease assay was used to genotype the KCNJ10 single nucleotide polymorphism c.1037C > T (dbSNP: rs1130183) that alters amino acid at position 271 from arginine to cysteine. RESULTS: Replication analysis revealed a significant decrease of the Cys271 allele frequency in 446 IGE patients compared to controls (chi2 = 3.52, d.f. = 1, P = 0.030, one-sided; OR(Cys271+) = 0.69; 95% CI: 0.50-0.95). Among the IGE subgroups, lack of the Cys271 allele was accentuated in the JME group (chi2 = 5.20, d.f. = 1, P = 0.011, one-sided). CONCLUSION: Our results support previous evidence that the common KCNJ10 Arg271Cys missense variation influences seizure susceptibility of common IGE syndromes.

Alleles↗
PubMedDate not supplied

A patient undergoing pancreaticoduodenectomy in whom involved common hepatic artery anomalously arising from the superior mesenteric artery was removed and reconstructed.

Identifying anatomical variations of the celio-mesenteric arterial branches is important when performing pancreaticoduodenectomy. A relatively rare variation is the common hepatic artery entirely originated as a branch of the superior mesenteric artery. This type of variation is termed hepatomesenteric trunk type common hepatic artery, in which an accessory left hepatic artery arising from the celiac trunk is absent. Preservation of hepatomesenteric trunk type common hepatic artery is indispensable during pancreaticoduodenectomy because fatal hepatic injury or leak of hepaticojejunostomy can occur. The present case report shows a patient with pancreatic head tumor in whom hepatomesenteric trunk type common hepatic artery was involved by the tumor. The patient underwent pancreaticoduodenectomy during which the involved hepatomesenteric type common hepatic artery was removed and reconstructed using saphenous venous grafts. Histopathological examination showed double cancers which were composed of an advanced ductal adenocarcinoma of the pancreas and early bile duct adenocarcinoma. The patient is alive 18 months after the surgery without recurrence.

Adenocarcinoma↗
PubMed1997

Genetic predictors of common disease: apolipoprotein E genotype as a paradigm.

PURPOSE: Genetic variation of a common genetic polymorphism at the structural locus for apolipoprotein E (apoE) has been associated with risk of elevated serum lipids, coronary artery disease, and Alzheimer disease, all of which are multifactoral disorders and are inherited in a complex fashion. Although the apoE polymorphism is only one risk factor in a complex pattern of inheritance, it gives us a foothold into the understanding of the genetic architecture of these disorders. However, apoE also exemplifies the complications that can arise in the use of genetic markers to predict disease. This paper considers the study of apolipoprotein E genotype effects as an example of the following analytical complications: changes in allele frequencies and allele effects with age, pleiotrophic effects of genetic loci, the existence of more than one alternative allele at a locus, and the expectation of a variety of interactions. METHODS: Publications that exemplify these complications are cited and discussed. No original analyses are presented. RESULTS: There is evidence that the relative frequency of the apoE epsilon4 allele declines with age after the sixth decade of life and that the effects of the APOE allele on lipids also may be age-dependent. Grouping of genotypes may not accurately characterize the effects of individual genotypes. Interactions between APOE genotype and a number of factors, including family history of dementia, are demonstrated for the effects of APOE in Alzheimer disease as well as for the effects of apoE on serum lipids. CONCLUSION: Careful attention must be paid to these and other analytical issues when genotype is a predictor.

Alleles↗
PubMed2002

Sequence variations within protein families are linearly related to structural variations.

It is commonly believed that similarities between the sequences of two proteins infer similarities between their structures. Sequence alignments reliably recognize pairs of protein of similar structures provided that the percentage sequence identity between their two sequences is sufficiently high. This distinction, however, is statistically less reliable when the percentage sequence identity is lower than 30% and little is known then about the detailed relationship between the two measures of similarity. Here, we investigate the inverse correlation between structural similarity and sequence similarity on 12 protein structure families. We define the structure similarity between two proteins as the cRMS distance between their structures. The sequence similarity for a pair of proteins is measured as the mean distance between the sequences in the subsets of sequence space compatible with their structures. We obtain an approximation of the sequence space compatible with a protein by designing a collection of protein sequences both stable and specific to the structure of that protein. Using these measures of sequence and structure similarities, we find that structural changes within a protein family are linearly related to changes in sequence similarity.

Amino Acid Sequence↗
PubMed2000

DRB3 alleles with variations in the annealing sites of commonly used amplification primers.

New HLA alleles are often identified initially from observing uncommon patterns found in low-resolution typing performed via polymerase chain reaction using sequence-specific oligonucleotide probes (PCR-SSOP). Recently, the HLA-DR oligotyping analysis of two Caucasian, one Caucasian/American Indian and two African American individuals resulted in the identification of three novel DRB3 alleles. Using DRB-specific primer sets commonly employed in amplification-based typing, all four individuals were originally characterized as DRB3 negative. Direct sequencing identified DRB3*0104 (variation at codon 8, TCG instead of TTG), and DRB3*0101202 (variation at intron (-13), G instead of C). One individual appeared to carry a DR52-associated DRB1 allele without an associated DRB3 allele. Lack of conservation at the junction of intron 1 and exon 2 of the DRB3 gene suggests that commonly used DRB-specific primer sets may need to be modified.

Alleles↗
PubMed2000

Genetic variation in human stromelysin gene promoter and common carotid geometry in healthy male subjects.

A common variant in the promoter of the human stromelysin gene, causing reduced enzyme expression, has been associated with the progression of coronary atherosclerosis. On the other hand, increased stromelysin activity may promote plaque rupture. The present study was undertaken to investigate the relationship between the genetic variation in the human stromelysin gene promoter and common carotid geometry. Forty-two healthy male subjects without major coronary heart disease risk factors were investigated. The polymorphism in the stromelysin gene promoter was studied through polymerase chain reaction amplification with the use of mutagenic primers. Age, blood pressure, lipids, glucose, viscosity, and body mass index were similar in homozygotes for the 5A allele (5A/5A), heterozygotes (5A/6A), and homozygotes for the 6A allele (6A/6A). Serum matrix metalloproteinase-3 levels did not differ significantly among genotypes. Common carotid diameters and intima-media thickness, measured by noninvasive ultrasonography, were significantly larger in 6A/6A subjects (for respective 6A/6A, 5A/6A, and 5A/5A subjects, diameter at the R wave was 0.63+/-0.09, 0.55+/-0.06, and 0.53+/-0.04 cm [mean+/-SD], P<0.005 by ANOVA; intima-media thickness was 765+/-116, 670+/-116, and 630+/-92 microm [mean+/-SD], P<0.05 by ANOVA). Wall shear stress, calculated as blood velocityxblood viscosity/internal diameter, was significantly lower in 6A/6A subjects (for respective 6A/6A, 5A/6A, and 5A/5A subjects, mean wall shear stress was 10.4+/-2.9, 13.5+/-3.5, and 12.6+/-1.9 dyne/cm(2) [mean+/-SD], P<0.05 by ANOVA). The results demonstrate that the gene polymorphism in the promoter region of stromelysin is associated with structural and functional characteristics of the common carotid artery in healthy male subjects without major risk factors for atherosclerosis. Individuals with the 6A/6A genotype (associated with lower enzyme activity) show a triad of events, namely, increased wall thickness, enlarged arterial lumen, and local reduction of wall shear stress, which might predispose them to atherosclerotic plaque localization.

Adult↗
PubMed1993

Sequence variation in the androgen receptor gene is not a common determinant of male sexual orientation.

To test the hypothesis that DNA sequence variation in the androgen receptor gene plays a causal role in the development of male sexual orientation, we have (1) measured the degree of concordance of androgen receptor alleles in 36 pairs of homosexual brothers, (2) compared the lengths of polyglutamine and polyglycine tracts in the amino-terminal domain of the androgen receptor in a sample of 197 homosexual males and 213 unselected subjects, and (3) screened the the entire androgen receptor coding region for sequence variation by PCR and denaturing gradient-gel electrophoresis (DGGE) and/or single-strand conformation polymorphism analysis in 20 homosexual males with homosexual or bisexual brothers and one homosexual male with no homosexual brothers, and screened the amino-terminal domain of the receptor for sequence variation in an additional 44 homosexual males, 37 of whom had one or more first- or second-degree male relatives who were either homosexual or bisexual. These analyses show that (1) homosexual brothers are as likely to be discordant as concordant for androgen receptor alleles; (2) there are no large-scale differences between the distributions of polyglycine or polyglutamine tract lengths in the homosexual and control groups; and (3) coding region sequence variation is not commonly found within the androgen receptor gene of homosexual men. The DGGE screen identified two rare amino acid substitutions, ser205-to-arg and glu793-to-asp, the biological significance of which is unknown.

Base Sequence↗