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Biomedical subjects

M Anderson

Publications and source records attributed to M Anderson.

At least 307 records · Page 17Linked to original sources
PubMed1991

Forage-related nitrate toxicoses possibly confounded by nonprotein nitrogen and monensin in the diet used at a commercial dairy heifer replacement operation.

Two clinically different episodes of nitrate toxicosis in heifers at the same dairy were evaluated to determine whether dietary supplements could have contributed to the confounding signs of illness. The first episode followed a 24-hour period of feeding mismanagement and resultant overconsumption of both a protein/nonprotein nitrogen supplement and a monensin supplement. This episode was characterized by ataxia, bloating, and death, without the classic clinical signs of dyspnea, salivation, cyanosis, and dark-colored blood, or the cardinal histologic changes of cyanosis, tissue staining, petechiations, or congestion. Approximately 5 weeks later, another episode developed, without the feeding mismanagement or the presence of supplements, and was characterized by classic signs of nitrate toxicosis along with response to methylene blue treatment. In both episodes, the feed source was the same, with high concentrations of nitrate. Heifers of both episodes had high ocular nitrate values, confirming the toxicoses. The difference was the availability of supplements. Calculation of exposure makes it unlikely that either the nonprotein moiety or the monensin moiety could have reached toxic values. However, the cell-level effects of monensin may have caused the animals to not display classic signs of nitrate toxicosis, confusing the diagnosis and treatment. This report demonstrates how field toxicosis can differ from reports of toxicoses caused by single etiologic agents. Practitioners must be aware of the potential for interactions between (and confounding by) commercially used feed components.

Animal Feed↗
PubMed1991

The development of contingent discourse ability in autistic children.

This study investigated communicative competence in autistic children. Six autistic boys were matched to six children with Down syndrome on age and language level. For each child four samples of spontaneous speech over the course of 1 year were analysed. Child utterances were coded for adjacency, contingency and various categories of contingent discourse that either did or did not add new information. Autistic children wer found to be more non-contingent, and to show no developmental change in their contingent discourse, especially in categories of contingent discourse that added new information.

Autistic Disorder↗
PubMed1991

Bilateral oophorectomy and hysterectomy in the treatment of intractable pelvic pain associated with pelvic congestion.

OBJECTIVE: To determine whether bilateral oophorectomy combined with hysterectomy is an effective treatment for chronic pelvic pain due to congestion. DESIGN: Prospective non-randomized single centre study. SETTING: Tertiary referral centre to a specialist pelvic pain clinic in a teaching hospital. SUBJECTS: 36 women, 33 of whom had failed to obtain long term relief of pain on medical therapy. MAIN OUTCOME MEASURES: Relief of pain, coital frequency, and effect on daily life. Histology of uterus and ovaries. RESULTS: Median pain score on visual analogue scale fell from a pre-operative value of 10 to 0 at one year. Twelve of the 36 women had some residual pain at one year postoperatively, but in only one woman was the pain affecting her daily life. Thirty women were noted to have pelvic tenderness pre-operatively, at one year, 26 had no tenderness and four minimal tenderness on pelvic examination. The median frequency of sexual intercourse increased from once per month preoperatively to eight times per month one year postoperatively. The uterus was histologically normal in 25 women, adenomyosis was present in eight of whom two had ovarian endometriosis. Fibroids were present in three and endometriosis was found confined to the ovaries in one woman. Multiple peripheral cysts were present in the ovaries of 25 women. CONCLUSION: Bilateral oophorectomy combined with hysterectomy and hormone replacement therapy is an effective treatment for chronic pelvic pain due to venous congestion, which has failed to respond to medical treatment and leads to restoration of normal coital function and daily life.

Activities of Daily Living↗
PubMed1991

In vitro susceptibility of Brucella melitensis to antibiotics.

The in vitro susceptibilities of 86 recent clinical isolates of Brucella melitensis to minocycline, streptomycin, co-trimoxazole, rifampin, and six fluoroquinolones were determined. Minocycline exhibited the lowest MIC and was followed by rifampin and streptomycin. Among the quinolones, WIN 57273 and ciprofloxacin were the most active agents. No antibiotic combination of these agents exhibited synergy against 15 selected isolates. In killing rate experiments, streptomycin exhibited the most rapid kill (less than 12 h), while a complete kill with minocycline, rifampin, and ciprofloxacin was delayed up to 48 h. The combinations of streptomycin with each of minocycline, rifampin, or ciprofloxacin exhibited the fastest kills (within 2 h), while with the other combinations, a complete kill was delayed up to 96 h. These results demonstrate the discrepancy between the results of various in vitro methods in evaluating the antibiotic susceptibility of B. melitensis.

Anti-Bacterial Agents↗
PubMed1991

Regional deposition of 3.6-micron particles and lung function in asthmatic subjects.

In a group of moderately severe asthmatic subjects, regional deposition of 3.6-microns (aerodynamic diameter) monodispersed Teflon particles labeled with 111In was studied twice. The particles were inhaled with maximally deep inhalation at 0.5 l/s. Lung retention was measured at 0, 6, 24, and 48 h by use of a profile scanner equipped with two 13 x 5-cm NaI crystals. The retentions at 24 (Ret24) and 48 h were highly correlated (r = 0.96 with a slope of the regression line close to 1). There was a poor correlation between retention at 6 h and Ret24 (r = 0.54). The Ret24 values at the two exposures were well correlated (r = 0.86). There were significant correlations between airway resistance as well as single-breath nitrogen test phase III and Ret24 (r = 0.70 and 0.67, respectively). The correlation between single-breath nitrogen test phase III and Ret24 persisted also when only subjects within a narrow interval of airway resistance were included. The study indicates that regional deposition can be studied by measurements of Ret24 in subjects with moderately severe asthma and that it is dependent on changes in both large and small airways.

Administration, Inhalation↗
PubMed1991

(6R,8S)-(2-benzimidazolyl)hydroxymethylpenicillanic acids as potent antibacterial agents and beta-lactamase inhibitors.

(6R,8S)-(2-Benzimidazolyl)hydroxymethylpenicillanic acids (1a-1x) are potent antibacterial agents and beta-lactamase inhibitors against Gram-positive bacteria and Haemophilus influenzae. The corresponding (6R,8R)-isomers (2a-2x), the 6,6-spiro benzimidazole-penam alcohol (3), (7R,9S)-(2-benzimidazolyl)hydroxymethylcephalosporanic acid (4), and 6 beta-(2-benzimidazolyl)aminopenicillanic acid (5) are much less active as antibacterials or beta-lactamase inhibitors. The syntheses and structure-activity relationships of these compounds are discussed. Antibacterial activity and beta-lactamase inhibition data are presented.

Anti-Bacterial Agents↗
PubMed1991

Branched DNA amplification multimers for the sensitive, direct detection of human hepatitis viruses.

Branched oligonucleotides (bDNA) have been synthesized containing a unique primary segment and a set of identical secondary fragments covalently attached to the primary sequence through branch points. The primary sequence is designed to hybridize (directly or indirectly) to a target nucleic acid, such as hepatitis B virus (HBV) or hepatitis C virus (HCV) genomic DNA or RNA, respectively. The secondary fragments are used to direct the binding of multiple copies of a small oligonucleotide labelled with alkaline phosphatase. Assays for the presence of HBV and HCV based on the application of these branched amplification multimers have been devised. It is possible to detect as few as 1,000 hepatitis viral genomes directly.

Base Sequence↗
PubMed1991

Effect of vaccination with the R mutant Escherichia coli (J5) antigen on morbidity and mortality of dairy calves.

A prospective cohort study was undertaken to determine the efficacy of Escherichia coli 0111:B4 (J5) vaccination in dairy calves. Calves on 2 units were vaccinated when they were 2 to 3 days old and 2 weeks later with the J5 antigen or they were left unvaccinated, and were observed during the first 60 days of age for morbidity and mortality. Events recorded were death, the first case of illness, the first sign of a respiratory tract condition, the first sign of diarrhea, and the first treatment. The time to death or to a morbid event was examined as a function of vaccination status, using the Cox model of survival analysis, where serum IgG concentration at 2 to 3 days of age and gender of the calf were included to control confounding. Signs of morbidity in 517 calves were followed, 189 from unit 1 and 328 from unit 2. Vaccination was associated with a 2.15-fold reduction in risk of death on unit 2 (P = 0.042), but with a 2.43-fold increase in risk of death on unit 1 (P = 0.0035). The only association found between vaccination and morbidity was a 1.34-fold reduction in risk of respiratory tract signs for vaccinated calves on unit 2 (P = 0.055). Necropsy results and clinical investigations indicated that calves on unit 1 were poorly nourished and emaciated. Antibodies to J5 2 weeks after vaccination were significantly (P = 0.0002) lower in calves on unit 1 than in calves on unit 2. The findings offered a possible explanation for the adverse vaccination effect in calves on unit 1.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Activation of K-ras by codon 13 mutations in C57BL/6 X C3H F1 mouse tumors induced by exposure to 1,3-butadiene.

1,3-Butadiene has been detected in urban air, gasoline vapors, and cigarette smoke. It has been estimated that 65,000 workers are exposed to this chemical in occupational settings in the United States. Lymphomas, lung, and liver tumors were induced in female and male C57BL/6 X C3H F1 (hereafter called B6C3F1) mice by inhalation of 6.25 to 625 ppm 1,3-butadiene for 1 to 2 years. The objective of this study was to examine these tumors for the presence of activated protooncogenes by the NIH 3T3 transfection and nude mouse tumorigenicity assays. Transfection of DNA isolated from 7 of 9 lung tumors and 7 of 12 liver tumors induced morphological transformation of NIH 3T3 cells. Southern blot analysis indicated that the transformation induced by 6 lung and 3 liver tumor DNA samples was due to transfer of a K-ras oncogene. Four of the 7 liver tumors that were positive upon transfection contained an activated H-ras gene. The identity of the transforming gene in one of the lung tumors has not been determined but was not a member of the ras family or a met or raf gene. Eleven 1,3-butadiene-induced lymphomas were examined for transforming genes using the nude mouse tumorigenicity assay. Activated K-ras genes were detected in 2 of the 11 lymphomas assayed. DNA sequencing of polymerase chain reaction-amplified ras gene exons revealed that 9 of 11 of the activating K-ras mutations were G to C transversions in codon 13. One liver tumor contained an activated K-ras gene with mutations in both codons 60 and 61. The activating mutation in one of the K-ras genes from a lymphoma was not identified but DNA sequence analysis of amplified regions in proximity to codons 12, 13, and 61 demonstrated that the mutation was not located in or near these codons. Activation of K-ras genes by codon 13 mutations has not been found in any lung or liver tumors or lymphomas from untreated B6C3F1 mice. Thus, the K-ras activation found in 1,3-butadiene-induced B6C3F1 mouse tumors probably occurred as a result of genotoxic effects of this chemical. The oncogenes most frequently detected in human pulmonary adenocarcinomas are K-ras genes. Activated K-ras genes have also been found in some human lymphomas. This suggest that activation of K-ras may be important in the induction of human pulmonary adenocarcinomas and lymphomas.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1990

Clinical manifestations of essential thrombocythemia in young adults.

Essential thrombocythemia (ET) is a myeloproliferative disorder characterized by isolated overproduction of platelets, thrombohemorrhagic complications, and a median age of 50-60. When it occurs in younger patients, the incidence of complications has been reported to be quite low, with a good long-term prognosis. We report a retrospective review of 13 patients with ET between the ages of 22 and 35 in which 11 were symptomatic at diagnosis, with only one remaining asymptomatic during follow-up. Three patients presented with potentially life-threatening complications (two myocardial infarctions, one stroke), although no deaths were observed. The majority of the nonlife-threatening complications were vaso-occlusive in nature, including erythromelalgia and transient neurologic symptoms. We conclude that ET in young adults is not always a benign disease and that potentially life-threatening complications are not rare. The optimum approach to treatment in this or any other age group remains uncertain.

Adult↗