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K Bell

Publications and source records attributed to K Bell.

At least 145 records · Page 8Linked to original sources
PubMed1991

The equine major plasma serpin multigene family: partial characterization including sequence of the reactive-site regions.

The equine Pi system, which is highly polymorphic and was considered to be controlled by a single locus, has been shown to be controlled by four loci (named Spi 1-4). This system is the equine equivalent of the major human plasma serpin (serine protease inhibitor), human alpha 1 PI. Twenty-two haplotypes of the equine Pi system have been characterized by two-dimensional electrophoresis, resulting in the assignment of pI, Mr, and bovine trypsin and chymotrypsin inhibition characteristics to 109 proteins. These proteins have been analyzed further to determine their relatedness to each other as well as to human alpha 1 PI using immunochemical, structural, and functional criteria. The amino acid sequences of the N termini and reactive-site regions have been determined on proteins from each of the four equine Spi loci. This allowed the designation of the proteins from the Spi 1 locus as being METserpins and the functional equivalents of human alpha 1 PI. The Spi 4 proteins are ARGserpins, and by alignment the Spi 2 proteins are ILEserpins, the first so far described. The P1 residue for the Spi 3 proteins was unable to be determined. The limited peptide and immunopeptide mapping revealed that proteins from all four loci were closely related, but within the four there were two pairs (Spi 1 and 2 and Spi 3 and 4) which were more related. All were probably derived from the same gene that gave rise to human alpha 1 PI.

Amino Acid Sequence↗
PubMed1991

Donkey and horse alpha 1 B-glycoprotein: partial characterization and new alleles.

1. The donkey postalbumin protein has been shown to be the equivalent of human alpha 1 B-glycoprotein by protein immunoblotting and N-terminal amino acid sequence. 2. The horse A1B system (already identified as the homologue of human alpha 1 B-glycoprotein) and the donkey alpha 1 B-glycoprotein were characterized further for terminal sialic acid content, isoelectric point, amino acid composition and affinity for the dye-ligand, Cibacron Blue F3GA (known to bind human alpha 1 B-glycoprotein). 3. Two new alleles in the horse A1B system were found, bringing the total number of alleles to five. No polymorphism was found in the donkey alpha 1 B system. 4. As expected the first 20 N-terminal residues of the donkey and horse proteins are highly conserved with only two differences being found. 5. The polymorphism of the horse alpha 1 B-glycoproteins may be due in part to differing numbers of terminal sialic acid residues and the higher electrophoretic mobility of the donkey alpha 1 B-glycoprotein may be due in part to increased sialylation. 6. The horse and donkey alpha 1 B-glycoproteins exhibited differences in affinity for the dye-ligand, Cibacron Blue F3GA, with the donkey alpha 1 B-glycoprotein not being bound.

Alleles↗
PubMed1991

The tammar wallaby major plasma serpin: partial characterization including the sequence of the reactive site region.

1. The putative equivalent of the human major plasma serpin (alpha 1-proteinase inhibitor or alpha 1-antitrypsin) in the tammar wallaby (Macropus eugenii) has been further characterized by structural (peptide and immunopeptide mapping and sequence studies) and functional analyses revealing close homology of the wallaby proteins to human alpha 1-proteinase inhibitor. 2. A sixth allele, Pi J, was detected and its products characterized in terms of pI, Mr, inhibitory spectra and terminal sialic acid content. 3. A recently-developed electrophoretic in situ oxidation/binding method was adapted to provide protein suitable for sequence analysis of the N-terminus and reactive site region including assignment of the P1 and P'1 residues. 4. All sequence analyses were performed on proteins or peptides (approximately Mr 3500) blotted onto polybrene treated GF/C or polyvinylidene difluoride membrane respectively. 5. The P5 to P'4 residues of the reactive centre are identical with those of the human inhibitor thereby allowing the wallaby inhibitor also to be classified as a METserpin. 6. The P1 methionine is presumably responsible for the oxidation sensitivity observed in the electrophoretic in situ functional assay for the wallaby inhibitor. 7. The plasma concentration of the wallaby inhibitor is similar to that reported for human alpha 1-proteinase inhibitor.

Alleles↗
PubMed1991

Expansion of the canine A blood group system.

A detailed study of the canine A blood group system was undertaken, resulting in the expansion of this system into a three-factor, four-allelic one with the recognition of an additional subtype, a3. The serological and extensive family data supported the proposed genetic theory of four alleles with dominance with the order being Aa1, Aa2, Aa3 and A-. Gene frequencies of the alleles were determined in various breeds of dogs with frequencies in the general Brisbane population being 0.244 (Aa1), 0.042 (Aa2), 0.045 (Aa3) and 0.669 (A-).

Alleles↗
PubMed1991

Use of multiple markers for investigation of an epidemic of Shigella sonnei infections in Monroe County, New York.

Antibiotic susceptibility patterns, plasmid profiles, and endonuclease restriction analysis of plasmid DNA were used in the investigation of an epidemic of Shigella sonnei infections in Monroe County, New York, in 1988 and 1989. The epidemic peaked during the winter, included the simultaneous transmission of the disease from person to person and from common food sources, and especially affected inhabitants of the poor, inner-city neighborhoods, young children of both sexes, and women. Resistance to ampicillin, tetracycline, or trimethoprim-sulfamethoxazole, encoded in a 70-MDa plasmid, was found in most of the examined isolates. Unexpectedly, isolates from patients involved in a food-borne outbreak exhibited three different antibiotic susceptibility patterns, suggesting deletion of antibiotic resistance determinants in some strains. Antibiograms clearly separated food-borne outbreak-related and non-foodborne outbreak-related strains, distinguished more strains than did the plasmid profiles, and were useful in tracing the dissemination of individual isolates in the community. Restriction endonuclease analysis substantially increased the discriminatory value of plasmid profiles and validated the antibiogram results. The present study illustrates the complexity of epidemics of S. sonnei infections and shows the value of combining different biological markers in the investigation.

Adolescent↗
PubMed1991

Are demented patients with Parkinson's disease accurately reflected in prevalence surveys? A survival analysis.

We re-reviewed 257 patient records previously reviewed for an incidence study of dementia in Parkinson's disease (PD) to determine the frequency, date of death, and cause of death. We posited that if disease duration is shortened when dementia occurs, then dementia may be far more common than reflected in prevalence studies. There were 17 deaths among 65 demented patients and 28 deaths among 168 nondemented patients. When we matched a subset of the nondemented patients to the demented patients by age and disease duration distributions, the demented subjects had significantly more deaths (p less than 0.02), and survival among demented subjects was decreased (p less than 0.05). Dementia was a significant predictor of death in this sample. We conclude that dementia reduces survival in patients with PD. Incidence is a much better measure of dementia in PD than prevalence because shortened duration makes it less likely to detect dementia in prevalence surveys.

Aged↗
PubMed1991

Renal alpha 1-adrenergic receptor subtypes: MDCK-D1 cells, but not rat cortical membranes possess a single population of receptors.

Recent work has demonstrated that alpha 1-adrenergic receptors are composed of at least two subtypes, termed alpha 1a and alpha 1b. It has been proposed that these subtypes may be linked to distinct second messenger systems. In the current studies, we have compared the properties of alpha 1-adrenergic receptors in rat renal cortical membranes with those in MDCK-D1 cells, a clonal cell line derived from distal tubule/collecting duct. Competitive binding studies with [3H]prazosin and compounds [5-methylurapidil, (+)-niguldipine, WB4101, and oxymetazoline] that distinguish high affinity (alpha 1a) and low affinity (alpha 1b) sites indicated that rat renal cortical membranes contain about 50% of each class of site. In contrast, MDCK-D1 cells contained a single population of low affinity sites. 5-Methylurapidil, but not the other compounds, recognized binding sites in these cells with a substantially lower affinity than has been observed for the low affinity site in other tissues and in parallel studies with renal cortical membranes. [3H]Prazosin binding sites in these cells, as well as alpha 1-adrenergic receptor-mediated arachidonic acid release and phosphoinositide and phosphatidylcholine hydrolysis, were sensitive to inactivation by chloroethylclonidine (IC50 approximately 0.7 microM), as expected for alpha 1b receptors. However, alpha 1-adrenergic receptors of MDCK-D1 cells required extracellular calcium for biological response, unlike what has been hypothesized for the alpha 1b receptor subtype. These data indicate that the population of alpha 1-adrenergic receptors of distal tubule/collecting duct cells likely consists of receptors of the alpha 1b subtype. The low affinity binding of 5-methylurapidil and the requirement for extracellular calcium for biological response in these cells suggest that this receptor may not be identical to the alpha 1b receptor that has been observed in other systems.

Animals↗
PubMed1990

Inhibition of catalase and epoxide hydrolase by the renal cystogen 2-amino-4,5-diphenylthiazole and its metabolites.

Subchronic feeding of 2-amino-4,5-diphenylthiazole (DPT) to rats results in the development of renal cysts and has been used as a model system to study polycystic kidney disease. Because previous studies revealed changes in renal enzymes following DPT administration, a possible direct effect of DPT and its phenolic metabolites on catalase and a related enzyme, epoxide hydrolase, was examined. Experiments with three in vitro systems (suspensions of rabbit renal tubules, rat kidney homogenates, and commercially obtained bovine liver catalase) revealed direct inhibition of catalase activity by the diphenolic metabolite (diOH- DPT: 2-amino-4,5di(4'-hydroxyphenyl)-thiazole), the known renal cystogen nordihydroquaiaretic acid (NDGA) 2-amino-4(4'-hydroxyphenyl),5-phenyl-thiazole (4OH-DPT), and the known catalase inhibitor 3-amino-1,2,4-triazole; DPT did not inhibit catalase activity. Following oral administration to rats of the DPT congeners, 4OH-DPT caused the greatest decrease in both renal catalase and cytosolic epoxide hydrolase activities and the shortest time to onset of cystic lesions. In vitro, mouse liver cytosolic epoxide hydrolase activity was substantially inhibited by 4OH-DPT and dioH-DPT, and NDGA, but not by 2-amino-4-phenyl,5-(4'-hydroxyphenyl)-thiazole (5OH-DPT) or DPT itself. Microsomal epoxide hydrolase (mEH) activity was inhibited by 4OH-DPT, unaffected by DPT or dioH-DPT, and stimulated 2-fold by 5OH-DPT. Finally, mEH activity was substantially higher in samples of normal human kidney than in samples of kidney derived from a patient with autosomal recessive polycystic kidney disease; no differences were observed in cEH activity in these samples. Although the role of altered catalase and epoxide hydrolase activities in cystogenesis is unknown, DPT-induced cyst formation is associated with loss of these enzyme activities in kidney tissue. To our knowledge, this is the first report of an in vivo diminution of cytosolic epoxide hydrolase activity by xenobiotics.

8,11,14-Eicosatrienoic Acid↗
PubMed1990

Feline whey proteins: identification, isolation and initial characterization of alpha-lactalbumin, beta-lactoglobulin and lysozyme.

1. Both alpha-lactalbumin and beta-lactoglobulin-like proteins were detected in the whey fraction of feline milk by immunoblotting with rabbit antisera to alpha-lactalbumin and beta-lactoglobulin, respectively. 2. alpha-Lactalbumin was found to occur in both glycosylated and unglycosylated forms in approximately equal concentrations. No polymorphism of feline alpha-lactalbumin was found. 3. Feline beta-lactoglobulin-like proteins produced complex electrophoretic patterns that appear to be determined by three distinct loci. Between two and five genetic variants are expressed by each locus. 4. Lysozyme was detected at levels of approximately 1 mg/ml in skim milk. 5. The identifications of the proteins as alpha-lactalbumin, beta-lactoglobulin and lysozyme were confirmed by determination of N-terminal amino acid sequences.

Amino Acid Sequence↗
PubMed1990

Haemoglobin, serum albumin and transferrin variants of Bali (Banteng) cattle, Bos (Bibos) javanicus.

1. Individual blood samples from 144 Bali (Banteng) cattle [Bos (Bibos) javanicus] in the Northern Territory of Australia and from 61 Bali cross cattle, were examined by zone electrophoresis to determine the variants of haemoglobin, serum albumin and transferrin that are present. 2. Of the common cattle haemoglobin variants (A and B) only variant B occurs in the Bali cattle samples. A second variant, designated CBali, occurs in Bali cattle either as the heterozygote (B CBali) or as the homozygote, the frequencies of occurrence indicating a two-allele system of inheritance without dominance. The CBali cross samples may exhibit the homozygous or heterozygous A variant. 3. The CBali variant has an electrophoretic mobility intermediate between those of the A and B variants at pH 8.6 and 9.1 but closer to B than to A (B greater than C greater than A). It appears to be similar in mobility to the C variants found in Indian Khillan (CKhillan) by Naik, Sukumaran and Sanghvi (Anim. Prodn, 1965 I, 275-277), and in Asian cattle by Oishi, Abe and Namikama (Immunogenet. Lett., 1968 5, 170-173) and Abe, Mogi, Oishi, Tanaka and Suzuki (Proc. XIIth Europ. Conf. Anim. Blood Groups Biochem. Polymorphisms 1972, pp. 225-228), but appreciably different from those in Kenyan and Rhodesian cattle (CRhodesia) found by Braend (Anim. Blood Grps Biochem. Genet., 1971 2, 15-21) and Carr (Rhod. J. agric. Res., 1964 3, 62-62A), respectively. It is also different in mobility from the C variant found by Winter, Mayr, Schleger, Dworak, Krutzler and Burger (Res. vet. Sci., 1984 36, 276-283) in the mithun.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1990

Equus przewalskii plasma protease inhibitor (Pi) system.

A detailed biochemical characterization of four of the five previously described alleles of the plasma protease inhibitor (Pi) system of Equus przewalskii was performed using both one- and two-dimensional electrophoretic techniques. The proteins have been characterized in terms of isoelectric point, relative molecular mass, inhibitory activity to bovine trypsin and chymotrypsin, immunochemical cross-reactivity, terminal sialic acid content and enzyme:inhibitor complex formation and the oxidation sensitivity of this interaction. Using these functional criteria, only three loci (Spi 1, 2 and 3) were found to control the plasma Pi proteins of the E. przewalskii haplotypes. In contrast a fourth locus, Spi 4, was found in some E. caballus haplotypes. The significance of these results with respect to the complexity of the protein pattern exhibited by the equine Pi multigene family is discussed.

Alleles↗
PubMed1990

Comparison of epidemic and endemic group G streptococci by restriction enzyme analysis.

Restriction enzyme profiles of group G beta-hemolytic streptococci associated with a point source outbreak and an outbreak of sporadic pharyngitis in two different communities were compared. To asses the epidemiologic utility of this approach for studying group G streptococci, DNA fingerprints of strains responsible for a point source outbreak of pharyngitis associated with the consumption of contaminated food were compared with DNA fingerprints of pharyngeal isolates from children with pharyngitis seen at a pediatric practice during a 6-month period. In each epidemiologic situation, a single strain characterized by a unique restriction enzyme pattern predominated. The results are compatible with the conclusion that human infections could be limited to a few strains of group G streptococci which have the capacity to spread through a given population. The restriction enzyme profiles proved to be a highly specific and precise means of evaluating strain relatedness and of providing further understanding of the epidemiology of group G streptococcal infections.

Connecticut↗
PubMed1990

Vascular and avascular retinae in mammals. A funduscopic and fluorescein angiographic study.

Intraretinal blood vessels are present in some and absent in other vertebrate species, including the mammals. Among the marsupials, both vascular and avascular retinae are seen. We determined the funduscopic appearance of the eye, investigated the functional aspects of ocular blood flow in both types of retina in marsupials and compared our results with known patterns in placental mammals. The Australian polyprotodont marsupials, the Tasmanian devil, Sarcophilus harrisii, and the quoll, Dasyurus viverrinus, together with an American polyprotodont, the Virginia opossum, Didelphis virginiana, demonstrate variable degrees of tapetal differentiation, pigmentation and a very close parallel course of their intraretinal arteries and veins over considerable distances. Using the technique of fluorescein angiography, we found that retinal blood flow in the 3 vascular Australian species commenced with arterial filling. Early venous was seen next, followed by the capillary blush. This unusual sequence of vascular flow differs from that of the arterial-capillary-venous filling seen in placental mammals. This difference is most likely a consequence of the known looped, end artery organisation found within marsupial nervous systems, of which the retinae are a part. The 2 diprotodont marsupials examined, the brushtail possum, Trichosurus vulpecula, and the sugar glider, Petaurus breviceps, possess avascular retinae. Only a small residual tuft of fluorescein-impermeable vessels projects from the optic disc into the vitreous. Interestingly, the structural complexity of the central visual system in diprotodonts all of whom possess avascular retinae) is commonly accepted as being greater than that of the stem polyprotodont line (which possess vascular retinae). If retinal function matches this internal complexity, then retinal avascularity may, as in birds, be associated with superior vision. However, as the retinae of these mammals clearly lack any nutritive mechanisms directly analogous to those in the retinae of, say, birds or the megachiropteran bats, their retinal nutritive pathways remain enigmatic.

Animals↗
PubMed1990

An estimate of the incidence of dementia in idiopathic Parkinson's disease.

The proportion of patients with idiopathic Parkinson's disease (PD) who are considered demented ranges from 10% to 15%. Because dementia may affect survival in PD, the incidence rate of dementia, rather than proportion, would be a more accurate measure of disease frequency. We previously estimated the proportion of patients with PD and dementia to be 10.9% from the records of a cohort with the idiopathic form of PD in a major medical center. We reviewed the clinical records of this cohort after 4 years and 9 months to estimate the incidence rate of dementia. We identified 65 new cases of dementia from the 249 patient-records available. Using the number of person-years of follow-up for each case as the denominator, we estimated the overall incidence rate to be 69 per 1,000 person-years of observation. The mean age of this cohort was 71.4 years. The cumulative incidence of dementia increased with age. By 85 years of age, over 65% of the surviving members of the cohort were demented. The age-specific incidence rates for dementia in this cohort of PD were significantly greater than for a similarly aged cohort of healthy elderly people. The age-specific standard morbidity ratios indicated that, compared with people of similar ages, patients with PD have the highest increase in risk for dementia between ages 65 and 75.

Age Factors↗
PubMed1990

The carbohydrate side chains of the major plasma serpins of horse and wallaby: analyses of enzymatic and chemically treated (including 'Smith degradation') protein blots by lectin binding.

The carbohydrate side chains of the major plasma serpins of the horse and wallaby have been characterized by lectin analyses of protein blots from two-dimensional gels using the major human plasma serpin, alpha 1-protease inhibitor, as a control. Eight lectins were used in the characterization in conjunction with enzymatic deglycosylation of complex and high mannose side chains, chemical desialylation and defucosylation, and one round of 'Smith degradation', all being performed on the nitrocellulose blots. Assuming a standard complex side chain structure, the results of the 21 lectin/treatment combinations were interpreted as indicating that the equine proteins consist of partially sialylated biantennary side chains except for the most acidic proteins which have triantennary side chains. The wallaby proteins have bi- and triantennary side chains with a bisecting N-acetylglucosamine and fucose residue present.

Animals↗
PubMed1989

Frequencies of feline blood groups in the United States.

A survey of AB blood group frequencies among cats in the United States was undertaken, using feline blood typing reagents from Australia. We typed blood of 280 cats of both genders and various breeds within the Philadelphia area and 205 cats at 27 veterinary medical teaching hospitals (most cats had been used as blood donors in 1987) throughout the United States. All but 2 cats had type-A blood. A Himalayan cat in Philadelphia and a domestic shorthair cat from Florida, neither of which had been used as a blood donor, had type-B blood. Plasma of the 2 blood-group-Bcats contained strong isoagglutinins (greater than 1:8 titer) against type-A cells, thereby allowing their detection in a major cross-match test. Approximately 30% of tested plasma samples from blood-group-A cats had weak isoagglutinins (1:2 titer) against type-B cells. This limited survey suggests that cats in the United States, including blood donors, predominantly have type-A blood, and that blood-group-B cats are rare.

Animals↗
PubMed1989

Application of an affinity electrophoretic and in situ oxidation method to the study of the equine protease inhibitory proteins.

An affinity method was developed to investigate the interaction between protease and protease inhibitor by incorporating a protease incubation step into a two-dimensional electrophoretic separation of the plasma protease inhibitory proteins. This involved the application of the isoelectric focusing gel to filter paper saturated in the protease of choice before being placed on the second-dimensional polyacrylamide electrophoresis gel. General protein staining or immunoblotting was used to detect the protein or ligand in the complex. An in situ oxidation method was developed using the reagent chloramine T to investigate the effect of this reagent on the complexing abilities and inhibitory activities of the protease inhibitory proteins. Oxidation was performed either after electrophoresis prior to staining for enzyme inhibition or during two-dimensional electrophoresis prior to the aforementioned protease incubation. The latter allowed the effect of oxidation on complex formation to be examined. Whole plasmas were utilized as the sources of protease inhibitory proteins with the human and mouse being used as models. The equine protease inhibitory system was examined by the two methods and shown to consist of three classes of inhibitory proteins based on their susceptibilities to oxidation and abilities to form complexes with various proteases.

Animals↗