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Biomedical subjects

R Kirby

Publications and source records attributed to R Kirby.

At least 91 records · Page 5Linked to original sources
PubMed1992

Evolutionary origin of the class A and class C beta-lactamases.

The protein sequences of 18 class A beta-lactamases and 2 class C beta-lactamases were analyzed to produce a rooted phylogenetic tree using the DD peptidase of Streptomyces R61 as an outgroup. This tree supports the penicillin-binding proteins as the most likely candidate for the ancestoral origin of the class A and class C beta-lactamases, these proteins diverging from a common evolutionary origin close to the DD peptidase. The actinomycetes are clearly shown as the origin of the class A beta-lactamases found in other non-actinomycete species. The tree also divides the beta-lactamases from the Streptomyces into two subgroups. One subgroup is closer to the DD peptidase root. The other Streptomyces subgroup shares a common branch point with the rest of the class A beta-lactamases, showing this subgroup as the origin of the non-actinomycete class A beta-lactamases. The non-actinomycete class A beta-lactamase phylogenetic tree suggests a spread of these beta-lactamases by horizontal transfer from the Streptomyces into the non-actinomycete gram-positive bacteria and thence into the gram-negative bacteria. The phylogenetic tree of the Streptomyces class A beta-lactamases supports the possibility that horizontal transfer of class A beta-lactamases occurred within the Streptomyces.

Amino Acid Sequence↗
PubMed1992

The isolation and characterization of antibiotic biosynthesis genes.

Antibiotic biosynthesis pathways are found in a broad range of Gram positive prokaryotes, a smaller range of Gram negative prokaryotes and a limited range of eukaryotes. A variety of techniques can be used to identify the genes involved in the biosynthesis of these compounds ranging from genetic complementation and interspecific gene transfer to polymerase chain reaction amplification and transposon mutagenesis. The dissection of these cloned pathways and the understanding of their structure and regulation has led to insights into the structure and function of antibiotic biosynthesis genes. With new knowledge of the structural similarities and relationships between related antibiotic biosynthesis pathways, the possibility of directed manipulation of specific genes to allow synthesis of novel antibiotics is now possible.

Journal Article↗
PubMed1992

Quality of life in young adults with type 1 diabetes in relation to demographic and disease variables.

Sixty-nine young adults (mean age 21 (range 15-25) years) with Type 1 diabetes completed measures of diabetes knowledge and quality of life. Factor analysis of the quality of life scale resulted in the identification of three subscales (social relationships, diabetes concerns, and impact). There was no relation between any of the quality of life subscales with knowledge, or with multiple versus twice-daily insulin injection regimens. Higher self-rated diabetes satisfaction was related to lower fructosamine levels and better clinic attendance (p less than 0.05). Females reported a more negative impact of diabetes on their lives compared with males (p less than 0.05).

Adult↗
PubMed1991

Cholecalciferol rodenticide intoxication in a cat.

A 4-month-old 2.5-kg sexually intact female domestic shorthair cat was referred to the teaching hospital because of suspected cholecalciferol intoxication after ingestion of a cholecalciferol-containing rodenticide. At referral, the cat was hypercalcemic, hyperkalemic, and acidotic. Despite management of hypercalcemia and preservation of renal function with physiologic saline solution, furosemide, dopamine, and calcitonin, the cat died, apparently as a result of extensive pulmonary mineralization.

Animals↗
PubMed1991

Adolescent health behaviour and similarity-attraction: friends share smoking habits (really), but much else besides.

Smoking habits and related attitudes were assessed in a sample of 4059 11- to 16-year-olds who also identified their best friends from among their fellow respondents. Subjects' responses were directly collated with those of their friends and indicated a clear covariation of smoking status (controlling for sex and age) as anticipated from previous research in which adolescents have been asked to report on the smoking habits of their friends. Such covariation, however, was not specific to smoking habits, but generalized to related measures of attitude and normative beliefs, alcohol use, health locus of control, school performance, spending habits and socio-economic status. Similarities on these other attributes were much the same, whether or not friends shared each others' smoking habits. It is concluded that these data argue against a simplistic view of unidirectional 'peer group influence' and invite an interpretation of friendship choice based on multiple dimensions of similarity.

Adolescent↗
PubMed1991

Characterization of the sugarcane streak agent as a distinct geminivirus.

The relationship between maize streak virus and the geminivirus causing streak in sugarcane was investigated. The DNA of sugarcane streak virus does not cross-hybridize detectably with that of maize streak virus and vice versa. Restriction mapping of native replicative form viral DNA (genome size 2.7 kb) and of cloned viral DNA, combined with limited sequencing and estimated DNA sequence divergence, showed that sugarcane streak virus is as unrelated to maize streak virus and digitaria streak virus as these are different from each other. The virus is only distantly related to wheat dwarf virus and chloris striate mosaic virus. Based on these results, we propose that the agent causing sugarcane streak is a distinct geminivirus.

Blotting, Western↗
PubMed1990

Evolutionary origin of aminoglycoside phosphotransferase resistance genes.

The protein sequences of seven 3'-aminoglycoside phosphotransferases falling into the six identified types and three 6'-aminoglycoside phosphotransferases were analyzed to give a rooted phylogenetic tree. This tree supports the origin of these groups of enzymes in an ancestor closely related to the actinomycetes, and that horizontal transfer of the resistance genes occurred, possibly via transposons. The implications for genetic engineering of a novel antibiotic are discussed.

Actinomycetales↗
PubMed1990

Hyperprolactinemia in acute myeloid leukemia and indication of ectopic expression of human prolactin in blast cells of a patient of subtype M4.

The sera of 28 patients with acute myeloid leukemia AML--subtypes M1 to M6 were screened for human prolactin (h-PRL). Serum TSH (thyroid stimulating hormone), LH (luteinizing hormone), FSH (follicle stimulating hormone), beta-estradiol, free T4 (tetra-iodotyronine) and testosterone were also determined. It was found that in 16 of the 28 patients h-PRL was significantly elevated while all other endocrine values were normal. In a patient subtype M4 with elevated serum h-PRL we demonstrate by immunoblotting that the hormone and its dimer are present in the blast cells. This may reflect ectopic synthesis due to altered expression of homeobox genes and a requirement of h-PRL as a growth stimulant of the leukemic myeloblast.

Aged↗
PubMed1990

Structure of a Rhodococcus gene encoding pigment production in Escherichia coli.

A 2.1 kbp DNA fragment from Rhodococcus strain ATCC 21145 gave rise to the production of blue and pink pigments in Escherichia coli when cloned downstream of a strong promoter. The sequence of this DNA fragment contains a single open reading frame with a putative ribosome-binding site, potentially coding for a single protein of Mr 42,560. Deletion analysis and in vitro transcription-translation experiments support the hypothesis that pigment production in E. coli is due to a single enzyme whose catalytic activity is still unknown. This small pigment gene may become useful for the development of a new generation of chromogenic cloning vectors which do not require expensive substrates for the detection of gene expression.

Amino Acid Sequence↗
PubMed1989

Development of pLR591, a Streptomyces-Escherichia coli positive selection shuttle vector.

The Escherichia coli positive selection vector pEcoR251 was ligated with the broad host range, high copy number Streptomyces plasmid pIJ702 to produce pLR591, a Streptomyces-E. coli positive selection shuttle vector. The EcoRI and thiostrepton resistance genes of pLR591 were expressed in E. coli and Streptomyces lividans respectively. The positive selection shuttle vector pLR591 facilitates the construction in E. coli of genomic libraries which can be screened in Streptomyces strains.

Cloning, Molecular↗
PubMed1989

Critical care--the overview.

Important keys to successful patient management include: 1. Identify and treat the most life-threatening problems first. 2. Make the patient as stable as possible before undertaking stressful procedures. 3. The critical patient's condition is rapidly changing and requires intensive monitoring and frequent reevaluation. 4. It is important to anticipate complications and initiate monitoring procedures for early detection. 5. The trend of changes in monitored parameters is more significant than a single value. 6. Make sure that the treatment orders are clear and concise and that the technical staff and clinicians have the same interpretations of monitoring values and treatment regimens. 7. Many post-trauma complications do not become evident for 24 to 72 hours. 8. Do not take a patient's stable condition for granted. 9. There is less tolerance for error, indecisiveness, or delay in the critical patient.

Animals↗
PubMed1989

Acute renal failure as a complication in the critically ill animal.

Acute renal failure is associated with a high morbidity and mortality in the intensive care animal. The two most common causes are ischemic/reperfusion injury and insult from nephrotoxins. Damage to the renal cells (e.g., endothelial, tubular, or mesangial cells) and altered hemodynamics result in reduced glomerular blood flow, tubular backleak, tubular obstruction, and/or decreased glomerular permeability. Recognition of ARF during the initiation stage provides the optimal chance for recovery. Adequate circulatory blood volume and systemic blood pressure must be established prior to pharmacologic intervention. Once ARF is in the maintenance phase, metabolic consequences of uremia must be managed.

Acute Kidney Injury↗
PubMed1989

Cloning and expression of Rhodococcus genes encoding pigment production in Escherichia coli.

Pigment was produced by Escherichia coli cells carrying recombinant plasmids pNIL100, pNIL200 and pNIL400 containing DNA from Rhodococcus sp. E. coli cells containing pNIL100 or pNIL200 (with DNA inserts from Rhodococcus sp. JL10 and Rhodococcus sp. ATCC 21145 respectively) produced both blue and pink pigments, while cells containing pNIL400 (with a DNA insert from Rhodococcus sp. ATCC 21145) produced only pink pigment. Colonies of E. coli(pNIL100) and E. coli(pNIL200) were dark blue, whereas E. coli(pNIL400) colonies were pink. No pigment was detected in Streptomyces griseus transformants containing pNIL100, pNIL200 or pNIL400. Restriction endonuclease mapping indicated that the cloned DNA fragments were different. The pigment gene(s) in pNIL200 producing both the blue and pink pigments were contained within a 2.8 kb DNA fragment. The pigments produced by E. coli transformants containing pNIL200 were characterized by visible and UV spectroscopy. No similar pigments were detected in Rhodococcus sp. ATCC 21145.

Cloning, Molecular↗
PubMed1989

Characterization of southern African isolates of maize streak virus: typing of three isolates by restriction mapping.

The genomic replicative form DNAs (RF-DNA) of three maize streak virus isolates (MSV-CT, MSV-PE, and MSV-SW) from widely separated locations in southern Africa were characterized by restriction endonuclease mapping in order to assess the feasibility of using the technique to determine genetic variability between isolates. The viruses were transmitted to and propagated in laboratory-grown maize by the leafhopper vector Cicadulina mbila (Naudé). MSV-PE produced more severe symptoms than MSV-CT and MSV-SW; the isolates were serologically identical in 'western' immunoblot tests, but distinct in 'sandwich' enzyme-linked immunosorbent assays. RF-DNA of all three isolates was prepared from infected maize; the RF-DNA of MSV-CT and MSV-PE was cloned in a plasmid vector in Escherichia coli. Restriction maps were generated from this cloned DNA and from the RF-DNA of MSV-SWA. The maps were similar in regions expected to be conserved, but there were also important differences between all isolates. The implications of these results, and of relationships amongst these and other sequenced isolates of MSV, are discussed.

Africa, Southern↗
PubMed1989

Evolutionary relationship of three southern African maize streak virus isolates.

The aligned restriction endonuclease maps of three sequenced maize streak virus isolates, three restriction-mapped southern African maize streak virus isolates, and two other sequenced geminiviruses were used as a means of calculating the sequence divergence between these viruses. The degree of divergence was used to construct a phylogenetic tree for the viruses; this tree agrees well with predictions from sequence comparisons, and so the method can be used to study the relationship of geminivirus isolates without the labor and expense of sequencing each one.

Africa, Southern↗
PubMed1988

Methemoglobinemia associated with dermal application of benzocaine cream in a cat.

Benzocaine, an ester-type local anesthetic, was believed responsible for apparent methemoglobinemia in a cat. The cat was admitted with acute respiratory distress, vomiting, and collapse, which began 15 to 20 minutes after topical application of the drug. Treatment consisted of supportive therapy and intravenous administration of methylene blue. The respiratory rate improved within 5 to 10 minutes of methylene blue administration and continued over a period of 2 hours. Benzocaine-induced methemoglobinemia has been reported in man, dogs, and cats. This report supports the findings of others regarding the potential toxicity of topical ester-type local anesthetics.

Administration, Cutaneous↗