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Biomedical subjects

K O'Donnell

Publications and source records attributed to K O'Donnell.

At least 55 records · Page 3Linked to original sources
PubMed1997

A zinc-containing intraruminal device for facial eczema control in lambs.

A zinc-containing intraruminal device has been developed for protecting lambs against facial eczema. The rate of release of zinc from the device has been optimised, and its safety in use established. Under both experimental and farm conditions, the device gave excellent protection against the liver injury associated with facial eczema. The device relies upon erosion for release of zinc, and disappears completely when its charge of zinc has been released, leaving no metal or plastic residue in the rumen. This device has the potential to greatly ameliorate the problem of facial eczema in New Zealand.

Journal Article↗
PubMed1997

Evaluation of intraruminal devices for combined facial eczema control and trace element supplementation in sheep.

Intraruminal devices containing zinc oxide are very effective in preventing facial eczema in sheep. In the present study such devices augmented with various amounts of selenium and cobalt have been evaluated for their ability to improve the Se and CO status of pregnant ewes, as reflected by changes in blood Se and serum Vitamin B12 concentrations. Devices containing 16.4 mg of Se (as sodium selenate) and 20.4 mg of Co (as cobalt sulphate) were effective in increasing and maintaining elevated blood Se concentrations for at least 84 days and serum Vitamin B12 for 42 days. Such devices will therefore prevent trace element deficiencies in sheep as well as providing protection against facial eczema.

Journal Article↗
PubMed1997

The diagnosis of major depression in end-stage renal disease.

BACKGROUND: Although major depression commonly occurs in medically ill patients, it can be difficult to diagnose since depression and many medical illnesses share common physical symptoms. METHODS: This study was designed to evaluate patients with end-stage renal disease (ESRD) for major depressive disorder using three diagnostic approaches, to assess the Beck Depression Inventory as a screening instrument for major depression, and to examine the association of anhedonia with a diagnosis of major depression in ESRD patients who deny depressed mood. RESULTS: Rates of major depression varied from 6 to 34% according to the criteria that were used. The sensitivity of the Beck Depression Inventory was found to be modest. Anhedonia was a helpful clue for diagnosing depression in patients who denied depressed mood. CONCLUSIONS: The findings illustrate the current difficulties in applying DSM criteria for major depression to medical patients and underscore the need for more specific guidelines.

Adult↗
PubMed1996

Two S-phase checkpoint systems, one involving the function of both BIME and Tyr15 phosphorylation of p34cdc2, inhibit NIMA and prevent premature mitosis.

We demonstrate that there are at least two S-phase checkpoint mechanisms controlling mitosis in Aspergillus. The first responds to the rate of DNA replication and inhibits mitosis via tyrosine phosphorylation of p34cdc2. Cells unable to tyrosine phosphorylate p34cdc2 are therefore viable but are unable to tolerate low levels of hydroxyurea and prematurely enter lethal mitosis when S-phase is slowed. However, if the NIMA mitosis-promoting kinase is inactivated then non-tyrosine-phosphorylated p34cdc2 cannot promote cells prematurely into mitosis. Lack of tyrosine-phosphorylated p34cdc2 also cannot promote mitosis, or lethality, if DNA replication is arrested, demonstrating the presence of a second S-phase checkpoint mechanism over mitotic initiation which we show involves the function of BIME. In order to overcome the S-phase arrest checkpoint over mitosis it is necessary both to prevent tyrosine phosphorylation of p34cdc2 and also to inactivate BIME. Lack of tyrosine phosphorylation of p34cdc2 allows precocious expression of NIMA during S-phase arrest, and lack of BIME then allows activation of this prematurely expressed NIMA by phosphorylation. The mitosis-promoting NIMA kinase is thus a target for S-phase checkpoint controls.

Aspergillus nidulans↗
PubMed1996

Compensation to a department of medicine and its faculty members for the teaching of medical students and house staff.

BACKGROUND: Changes in the organization and financing of health care threaten to alter the prevailing system of financing the teaching of medical students and residents. Little information is available from private medical schools and teaching hospitals about the extent of teaching by faculty members or the mechanisms and levels of reimbursement for teaching. METHODS: We surveyed faculty members in the Department of Medicine at Columbia-Presbyterian Medical Center to ascertain the extent of their teaching activities. A standard number of hours was assigned to each activity, and the total number of teaching hours was calculated for each faculty member. Teaching of fellows and in continuing medical education programs was excluded. We also determined how much money the Department of Medicine received in payment for faculty members' teaching activities, and the sources of this compensation. RESULTS: In the 1992-1993 academic year, the 188 full-time faculty members spent a total of 46,086 hours teaching (mean [+/- SD], 245 +/- 178 hours per faculty member); 10,780 hours (23.4 percent) were spent teaching medical students, and 35,306 hours (76.6 percent) teaching house staff. Eighty percent of faculty members taught for 137 or more hours each. In a multivariate analysis including faculty rank, subspecialty division, years since graduation from medical school, sex, and tenure or clinical track, senior faculty members (P = 0.02), members of certain subspecialty divisions (P < 0.001), and women (P = 0.05) contributed more than the average number of teaching hours. An additional 56 non-full-time faculty members contributed a total of 5684 hours. The net reimbursement to the department for teaching totaled $965,808, or about $16 per hour of teaching by full-time faculty members, after the cost of fringe benefits was excluded. CONCLUSIONS: Faculty members of the department of medicine at a major medical center contribute a large number of hours teaching medical students and house staff. This effort is poorly compensated. Cost-containment efforts have the potential to jeopardize fragile social contracts at academic health centers whereby the faculty participates in teaching by contributing unreimbursed or underreimbursed time.

Academic Medical Centers↗
PubMed1996

Alveolar soft part sarcoma metastatic to the breast.

Metastasis to the breast is uncommon, with an incidence of 0.5-3%. Alveolar soft part sarcoma is rare, accounting for < 1% of malignant soft tissue tumors, which are themselves unusual. Excluding contralateral breast and hematologic malignant disease, the primary lesion in most cases of metastasis to the breast is melanoma, small cell carcinoma of the lung, or ovarian carcinoma, although rhabdomyosarcoma is the most common primary tumor in children. We describe a 26-year-old woman with no history of malignant disease who presented with two masses in the right breast that clinical evaluations and ultrasonography indicated were fibroadenomas. Pathological studies after excisional biopsy, however, indicated alveolar soft part sarcoma. Subsequent computed tomography showed the primary tumor in the anterior left thigh and multiple bilateral lung metastases. Because of the presence of distant metastases, the patient was treated with chemotherapy.

Adult↗
PubMed1996

Clinical and laboratory characteristics of a large cohort of symptomatic, human immunodeficiency virus-infected infants and children. AIDS Clinical Trials Group Protocol 152 Study Team.

BACKGROUND: A large cohort of antiretroviral therapy-naive, symptomatic, HIV-infected children were enrolled into a controlled therapeutic trial (AIDS Clinical Trials Group Protocol 152), providing an opportunity to describe their clinical and laboratory characteristics and determine age-related distinctions. METHODS: Study entry evaluations for 838 of 839 enrolled children were analyzed. Weight, head circumference (if < 30 months of age), neuroradiologic imaging of the head, developmental or cognitive status and neurologic examination were assessed. Laboratory studies included hemoglobin, absolute neutrophil count, CD4 cell count, serum amylase, alanine aminotransaminase, p24 antigen and HIV blood culture. Data were categorized by age (3 to < 12 months, 12 to < 30 months, 30 months to 6 years and > or = 6 years). RESULTS: Younger children had significantly higher rates of abnormalities before antiretroviral therapy, especially factors relating to growth and neurologic or cognitive function. Lower CD4+ cell counts and percentages as well as a positive serum p24 antigen correlated with lower weight-for-age Z scores and developmental indices. CONCLUSIONS: These data provide a description of the clinical characteristics of HIV-infected US children at the time antiretroviral therapy is initiated for HIV-related symptoms. The high rate of abnormalities of growth, development and cognitive ability that were observed in children < 30 months of age demonstrates that treatment strategies should be developed for earlier intervention.

AIDS-Related Opportunistic Infections↗
PubMed1995

Isolation of a functional homolog of the cell cycle-specific NIMA protein kinase of Aspergillus nidulans and functional analysis of conserved residues.

To investigate the degree of conservation of the cell cycle-specific NIMA protein kinase of Aspergillus nidulans, and to help direct its functional analysis, we cloned a homolog (designated nim-1) from Neurospora crassa. Over the catalytic domain NIM-1 is 75% identical to NIMA, but overall the identity drops to 52%. nim-1 was able to functionally complement nimA5 in A. nidulans. Mutational analysis of potential activating phosphorylation sites found in NIMA, NIM-1, and related protein kinases was performed on NIMA. Mutation of threonine 199 (conserved in all NIMA-related kinases) inhibited NIMA beta-casein kinase activity and abolished its in vivo function. This site conforms to a minimal consensus phosphorylation site for NIMA (FXXT) and is analogous to the autophosphorylation site of cyclic-AMP-dependent protein kinases. However, mutation of a unique cysteine residue found only in the catalytic site of NIMA and NIM-1 had no effect on NIMA kinase activity or function. Three temperature-sensitive alleles of nimA that cause arrest in G2 were sequenced and shown to generate three different amino acid substitutions. None of the mutations prevented accumulation of NIMA protein during G2 arrest, but all prevented the p34cdc2/cyclin B-dependent phosphorylation of NIMA normally seen during mitotic initiation even though p34cdc2/cyclin B H1 kinase activity was fully activated.

Amino Acid Sequence↗
PubMed1995

Current trends in molecular recognition and bioseparation.

Molecular recognition guides the selective interaction of macromolecules with each other in essentially all biological processes. Perhaps the most impactful use of biomolecular recognition in separation science has been in affinity chromatography. The results of the last 26 years, since Cuatrecases, Wilchek and Anfinsen first reported the purification of staphylococcal nuclease, have validated the power of biomolecular specificity for purification. This power has stimulated an explosion of solid-phase ligand designs and affinity chromatographic applications. An ongoing case in point is the purification of recombinant proteins, which has been aided by engineering the proteins to contain Affinity-Tag sequences, such as hexa-histidine for metal-chelate separation and epitope sequence for separation by an immobilized monoclonal antibody. Tag technology can be adapted for plate assays and other solid-phase techniques. The advance of affinity chromatography also has stimulated immobilized ligand-based methods to characterize macromolecular recognition, including both chromatographic and optical biosensor methods. And, new methods such as phage display and other diversity library approaches continue to emerge to identify new recognition molecules of potential use as affinity ligands. Overall, it is tantalizing to envision a continued evolution of new affinity technologies which use the selectivity built into biomolecular recognition as a vehicle for purification, analysis, screening and other applications in separation sciences.

Chromatography, Affinity↗
PubMed1995

Quantitation of cytomegalovirus in the blood of liver transplant recipients.

An assay for quantitation of cytomegalovirus (CMV) has been developed. The assay combines DNA amplification and enzyme-linked immunosorbent assay (ELISA) detection. In this study, the assay has been used to examine sequential buffy-coats from 32 consecutive liver transplant recipients. In a febrile patient, CMV titres in excess of 10(4) copies per 150,000 cells strongly suggest a diagnosis of symptomatic CMV infection. Antiviral therapy causes a rapid decline in viral titre. Viral titres are seen to rise presymptomatically in some patients. Median peak viral titres differ significantly between symptomatic patients (1.1 x 10(5)), asymptomatic CMV IgM-positive patients (1.7 x 10(3)), and asymptomatic CMV immunoglobulin (Ig)M-negative patients (2.9 x 10(2)). CMV quantitation can be used for diagnosis and surveillance and can also be used to monitor antiviral treatment.

Adult↗
PubMed1994

Timing of vulnerability of the brain to iodine deficiency in endemic cretinism.

BACKGROUND: Endemic cretinism, caused by severe iodine deficiency during pregnancy, is the world's most common preventable cause of mental retardation. It can be prevented by iodine treatment before conception, but whether it can be prevented or ameliorated by treatment during pregnancy or after delivery is not known. METHODS: In a severely iodine-deficient area of the Xinjiang region of China, we systematically administered iodine to groups of children from birth to three years of age (n = 689) and women at each trimester of pregnancy (n = 295); we then followed the treated children and the babies born to the treated women for two years. We used three independent measures of neural development: the results of the neurologic examination, the head circumference (which correlates with brain weight in the first postnatal year), and indexes of cognitive and motor development. Untreated children one to three years of age, who were studied when first seen, served as control subjects. RESULTS: The prevalence of moderate or severe neurologic abnormalities among the 120 infants whose mothers received iodine in the first or second trimester was 2 percent, as compared with 9 percent among the 752 infants who received iodine during the third trimester (through the treatment of their mothers) or after birth (P = 0.008). The prevalence of microcephaly (defined as a head circumference more than 3 SD below U.S. norms) decreased from 27 percent in the untreated children to 11 percent in the treated children (P = 0.006), and the mean (+/- SD) developmental quotient at two years of age increased (90 +/- 14, vs. 75 +/- 18 in the untreated children; P < 0.001). Treatment in the third trimester of pregnancy or after delivery did not improve neurologic status, but head growth and developmental quotients improved slightly. Treatment during the first trimester, which was technically problematic, improved the neurologic outcome. CONCLUSIONS: Up to the end of the second trimester, iodine treatment protects the fetal brain from the effects of iodine deficiency. Treatment later in pregnancy or after delivery may improve brain growth and developmental achievement slightly, but it does not improve neurologic status.

Brain↗
PubMed1994

Iodination of irrigation water as a method of supplying iodine to a severely iodine-deficient population in Xinjiang, China.

Severe iodine deficiency still occurs in many countries, and causes cretinism and mental impairment. In southern Xinjiang province, China, after usual methods of iodine supplementation had failed, we iodinated irrigation water to increase iodine in soil, crops, animals, and human beings. 5% potassium iodate solution, dripped into an irrigation canal for 12 or 24 days, increased soil iodine 3-fold, and crop and animal iodine 2-fold. Median urinary iodine excretion in children increased from 18 to 49 micrograms/L (two groups of similar age). The cost for iodine was US $0.05 per person per year. Soil iodine remained stable over one winter, and dripping of iodine during the second year (US $0.12 per person per year) resulted in a further 4-fold increase in soil iodine and a 1.8-fold increase in iodine in crops. We conclude that iodination of irrigation water is an advantageous and cost-effective method of supplying iodine in southern Xinjiang, and may be useful in other areas dependent on irrigation.

Agriculture↗
PubMed1994

Phylogeny of the yeast genera Hanseniaspora (anamorph Kloeckera), Dekkera (anamorph Brettanomyces), and Eeniella as inferred from partial 26S ribosomal DNA nucleotide sequences.

Partial 26S ribosomal DNA sequences of species assigned to the genera Hanseniaspora, Kloeckera, Dekkera, Brettanomyces, and Eeniella were determined. A phylogenetic analysis of the sequences showed that the genus Eeniella is derived within the genus Brettanomyces and that the genus Hanseniaspora (anamorph Kloeckera) is not closely related to the genus Dekkera (anamorph Brettanomyces). As a consequence, the name Eeniella is reduced to synonymy with the name Brettanomyces. In addition, our data do not support reassignment of certain Hanseniaspora species to the recently revived genus Kloeckeraspora.

Ascomycota↗
PubMed1994

Verifying the future of electronic eligibility verification.

Many vendors and potential users of eligibility verification systems know the obstacles that deter the widespread acceptance and implementation of the technology. On the following pages, executives of firms representing the payor, provider and clearinghouse communities express their perceptions regarding the status and need for online eligibility verification and its cost advantages.

Eligibility Determination↗
PubMed1992

HIV-1 sensitivity to zidovudine and clinical outcome in children.

In adults with the acquired immunodeficiency syndrome, long-term monotherapy with zidovudine selects for human immunodeficiency virus type 1 (HIV-1) strains with substantially reduced in-vitro susceptibility to the drug. We have assessed the relation between in-vitro resistance to zidovudine and clinical outcome in children, in whom disease progression is more rapid than in adults. We studied 23 children with symptoms of HIV-1 disease during extended monotherapy with zidovudine. An in-vitro assay was used to determine the concentration of zidovudine required to inhibit by 50% the replication of viral isolates (IC50) obtained after 9 to 39 months of treatment. Viral stocks of high enough titre to yield reproducible results were obtained from 19 of the children. During the following 6 months of therapy, 9 children were stable, 7 deteriorated, and 3 died. There was a highly significant relation between decreased zidovudine susceptibility and poor clinical outcome (p less than 0.001) but no relation between IC50 and age at start of therapy or length of time on treatment. Age-adjusted CD4 lymphocyte counts were lower at the start of treatment (p = 0.02) and at the time of sampling (p = 0.01) in children whose viral isolates had an increased zidovudine IC50. Initial serum p24 antigen levels were not predictive of subsequent emergence of resistant virus, but at the time of sampling for viral sensitivity higher p24 antigen levels were associated with raised IC50 (p = 0.004). The findings suggest that most children who become unresponsive to monotherapy with zidovudine, as judged by clinical criteria, will have changes in in-vitro sensitivity to the drug. In these children, an alternative antiretroviral therapy should be considered.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Ribosomal DNA internal transcribed spacers are highly divergent in the phytopathogenic ascomycete Fusarium sambucinum (Gibberella pulicaris).

Variation within the internal transcribed spacers (ITS1 and ITS2) and 5.8s ribosomal DNA gene of the heterothallic phytopathogenic filamentous fungus, Fusarium sambucinum (teleomorph = Gibberella pulicaris), was examined in 86 strains from diverse geographical locations by PCR amplification and direct sequencing in order to measure intraspecific divergence within the ITS region. Sequence analysis revealed three ITS types (A, B, C), within which divergence was extremely low (0-2.3%). Surprisingly, the level of intraspecific divergence observed between ITS types, A----B = 14.3%, A----C = 15%, and B----C = 4.6%, is much greater than that reported for any other species. The degree to which transition/transversions and insertion/deletions make up the pattern of ITS sequence evolution both within and between types was analyzed. The sequences of the ITS types exhibit a C-T transition bias together with a GC insertion/deletion bias. In comparison, the genic flanking sequences, including the 5.8s rDNA gene and 5' end of the 28s large nuclear rDNA, are highly conserved. By the criteria of mating and DNA-DNA hybridization, all the strains examined represent a single species. Discordance between the ITS sequence data and other molecular and genetic data on F. sambucinum is discussed.

Base Sequence↗