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Biomedical subjects

M Anderson

Publications and source records attributed to M Anderson.

At least 325 records · Page 18Linked to original sources
PubMed1990

A longitudinal study of language acquisition in autistic and Down syndrome children.

Findings from a longitudinal study of language acquisition in a group of autistic children are presented. Six autistic subjects and six children with Down syndrome, matched on age and MLU at the start of the study, were followed over a period of between 12 and 26 months. Language samples were collected in the children's homes while they interacted with their mothers. Samples of 100 spontaneous child utterances from the transcripts were analyzed using the following measures: MLU, Index of Productive Syntax, lexical diversity, and form class distribution. The results indicate that the majority of these autistic children followed the same general developmental path as the Down syndrome children in this study, and normal children reported in the literature, in the acquisition of grammatical and lexical aspects of language, and confirm previous findings suggesting that autism does not involve a fundamental impairment in formal aspects of language.

Autistic Disorder↗
PubMed1990

Expression of verapamil hypersensitivity in multidrug-resistant cells grown as multicellular spheroids.

It is known that certain multidrug-resistant cell lines are hypersensitive to verapamil and to some other membrane-active agents. We examined the expression of verapamil hypersensitivity in multidrug-resistant, verapamil-hypersensitive CHO cell line by cells grown in the form of multicellular spheroids. We found that although vincristine resistance is expressed at high levels in multicellular spheroids, we could not detect verapamil hypersensitivity when cells were grown in this form. Using a dry autoradiographic method to study the entry of [3H]-verapamil into the spheroids, we demonstrated that the lack of hypersensitivity was not due to incomplete drug penetration. We therefore propose that when hypersensitive multidrug-resistant cells are grown as three-dimensional spheroids, cellular interactions may modify the expression of verapamil hypersensitivity.

Animals↗
PubMed1990

Cleaning insect oocytes by dissection and enzyme treatment.

Vitellogenic oocytes from the cockroach Blattella germanica were dissected free of the surrounding follicle cell layer. The continued presence of a resting potential indicated that the defolliculated oocytes remained viable. In other experiments, lysozyme was injected into last nymphal instars; scanning electron micrographs showed that the bacteroids normally found between the follicle cell epithelium and the oocyte membrane were removed by this treatment. Oocytes from injected animals were known to be viable because they developed into living progeny. To assess the mode of action of lysozyme, defolliculated oocytes were exposed in vitro to lysozyme and then a hypotonic rinse; scanning electron micrographs showed that these oocytes were largely free of bacteroids.

Animals↗
PubMed1990

Ontario's underserviced area program revisited: an indirect analysis.

Financial incentive programs are used in various developed and developing countries to effect change in the geographic distribution of physicians. The Underserviced Area Program of Ontario is the longest running financial incentive program in Canada. It is described in detail and analyzed for its effectiveness in solving the problems of the maldistribution of physicians in northern Ontario. Using location quotients as an indirect measure shows that the maldistribution of physicians continues despite the implementation of the program. It is argued that the unidimensional solution of financial incentives cannot be used to solve the multidimensional issue of accessibility to health care in rural and remote areas.

Economics, Medical↗
PubMed1990

Gastroenterological aspects of AIDS in the Third World.

Gastrointestinal disease is the commonest presentation of AIDS in the Third World. Diarrhoea and weight loss are particularly common. Although many pathogens may be found, chronic cryptosporidiosis is the most frequent and there remains no specific effective therapy. Isospora belli is found in less than 10% of cases, but may be treated with cotrimoxazole, and long-term maintenance treatment to prevent relapse is effective. Oral disease, especially with candidiasis, is increasingly recognized and may be controlled with topical antifungal agents. The outlook for patients in the Third World who present with gastrointestinal opportunistic infections associated with HIV infection is particularly dismal. Specific antiviral therapy, which has at least brought some hope and longer survival to patients in developed countries, remains largely unavailable in the Third World.

Acquired Immunodeficiency Syndrome↗
PubMed1990

A double-blind comparison of intranasal budesonide with placebo for nasal polyposis.

Intranasal budesonide, 400 micrograms two times a day, was evaluated in 36 patients referred for treatment of nasal polyposis. The age range was 20 to 68 years. Polypectomy was done 5.6 (mean) times previously. After a 5-week, treatment-free, baseline period, patients were treated in a double-blind fashion with either budesonide or placebo during 4 weeks. After this treatment period, placebo-treated patients started receiving budesonide in an open trial for an additional 4 weeks. The patients rated their nasal symptoms daily. Nasal examinations and nasal inspiratory flow rate (IFR) measurements were done at clinic visits. After 3 and 4 weeks of treatment, the response to budesonide was significantly greater than response to placebo. The greater reduction in nasal blockage caused by polyps, observed on physical examination, p = 0.005, was mirrored by an increase in nasal IFR (p = 0.0001). Patient rating of the severity and frequency of nasal blockage were reduced more by budesonide than by placebo (p less than or equal to 0.0005). Switching placebo-treated patients to budesonide treatment resulted in a reduction of nasal blockage (p less than 0.001) and an increase in nasal IFR (p less than 0.001). The results demonstrate that topical nasal budesonide, 400 micrograms two times a day, is an effective treatment of nasal polyps.

Administration, Intranasal↗
PubMed1990

The inflammatory response in asthma exacerbation: changes in circulating eosinophils, basophils and their progenitors.

Circulating eosinophils, basophils and eosinophil/basophil (Eo/B) progenitors were examined in 12 patients at the time of an exacerbation of asthma accompanied by sputum eosinophilia and after resolution of the exacerbation with inhaled corticosteroid treatment. Differential counts were performed and peripheral blood non-adherent mononuclear cells were cultured for 14 days in methyl-cellulose to determine the number of Eo/B and granulocyte-macrophage (GM) colonies without knowledge of the clinical conditions or findings. With resolution of the asthma exacerbation on beclomethasone therapy, there were significant falls in circulating eosinophils, basophils and Eo/B colonies whereas GM colonies were unchanged. To elucidate whether the observed changes could be due to systemic absorption or local action of inhaled corticosteroid, seven subjects with allergic rhinitis and no current evidence of lower airway inflammation (no symptoms of asthma and normal methacholine airway responsiveness) received 14 days' treatment with the same dose of inhaled beclomethasone or of placebo in a double-blind randomized cross-over study. No significant changes in airway function or in circulating cell counts were observed. The results suggest reduced production of eosinophils and basophils after the resolution of an exacerbation of asthma. This effect may be due to reduced levels of airway-derived eosinophil-basophil growth and differentiation factors.

Adrenal Cortex Hormones↗
PubMed1990

The increased number of epithelial mast cells in nasal polyps and adjacent turbinates is not allergy-dependent.

Respiratory epithelial mast cells are an expression of airway inflammatory processes. Nasal epithelial mast cells are known to be increased in allergic rhinitis and have now been examined in patients with nasal polyps. Metachromatic cell counts (mean +/- standard error) expressed as the sum of large mast cells, atypical mast cells and basophils in epithelial scrapings of the inferior turbinates, assessed after Carnoy's fixation and toluidine blue staining (pH 0.5), were 37.5 +/- 29 in non-allergic normal control subjects (n = 11), 435 +/- 130 in polyp patients who were allergic (n = 18), and 699 +/- 267 in polyp patients who were not allergic (n = 8). Metachromatic cell counts in epithelial scrapings obtained in vivo from nasal polyps of allergic patients (n = 8) were 1769 +/- 962, and 2308 +/- 1544 from polyps of non-allergic patients (n = 5); metachromatic counts were 2089 +/- 633 in epithelial scrapings from excised polyps of allergic patients (n = 14) and 2214 +/- 640 from polyps of non-allergic patients (n = 13). It is concluded that the number of metachromatic cells in the epithelium of nasal polyps and the adjacent nasal mucosa is elevated compared with normal nasal epithelium and the increased number does not depend upon allergy.

Humans↗
PubMed1990

Separation of conjoined twins.

The incidence of conjoined twins is rare, occurring in one in 50-80,000 live births. The rarity of the occurrence presents quite a management challenge. The first case in New Zealand of successfully separated thoraco-omphalagus twins, presenting top-to-tail, is described.

Abdominal Muscles↗
PubMed1990

Perceptual dysfunction in poor readers: evidence for visual and auditory segmentation problems in a sub-group of poor readers.

The purpose of this study was to consider reading disorders in children within the context of their general perceptual development. A review of the literature suggested that visual and auditory perceptual skills advance from a holistic to an analytical approach, and that reading skills also show this progression. It was proposed that poor readers might show impairments in visual and auditory segmentation tasks, if these skills are important factors in reading development. This hypothesis was tested on a sample (N = 20) of poor readers in the primary age range who were assessed against reading age and chronological age control groups. The hypothesis was partially borne out, a quarter of the sample performing very poorly on both types of tasks. It was argued that segmentation problems in perceptual tasks may underlie reading failure in some children, although the direction of the causation has yet to be determined.

Auditory Perceptual Disorders↗
PubMed1990

Leptomyxid ameba, a new agent of amebic meningoencephalitis in humans and animals.

Amebae belonging to the order Leptomyxida are regarded as innocuous soil organisms incapable of infecting mammals. We report here the isolation of a leptomyxid ameba from the brain of a pregnant baboon (Papio sphinx) that died of meningoencephalitis at the San Diego Zoo Wild Animal Park. By using rabbit anti-leptomyxid serum in the immunofluorescence assay, we have identified the leptomyxid ameba in the brain sections of a number of human encephalitic cases from around the world as well as a few cases of meningoencephalitis in animals in the United States, which suggests that the leptomyxid amebae are potential etiologic agents of fatal meningoencephalitis in humans and animals.

Amebiasis↗
PubMed1990

Histologic assessment of neurons in rat models of cerebral ischemia.

We describe a method for typing neurons into four progressive stages of ischemic deterioration based on visual characterization of the nucleus in terms of its optical contrast, delineation along the nuclear-cytoplasmic interface, and its shape. Difficulty in assessing nuclear shape required the introduction of an angularity comparator chart to improve the investigator's accuracy. Three investigators typed neurons obtained from normal, ischemic, and ischemic-reperfused rat brains. Accuracy and reproducibility of the investigators' typing decisions with and without the angularity comparator charts were evaluated. The accuracy of subjective shape assessment was compared with objective digitizer measurements of the same. The angularity comparator charts reduced subjective shape classification error by two thirds, and group error (overall performance expressed by the coefficient of variance) decreased from 15.9% to 4.7% for Type I (normal cells), from 33.9% to 17.3% for Type II (cells with angular nuclei), from 15.5% to 14.1% for Type III (cells with smeared nuclei), and from 3.2% to 5.5% for Type IV (dead cells). Thus, Type I and IV neurons can be assessed at a higher reproducibility than the intermediate Types II and III. Our typing method can also be used to evaluate the effect of treatment regimes on ischemic neuronal damage.

Animals↗
PubMed1990

PH of endodontic medicaments used in pediatric dentistry: effects of dyadic combinations.

The optimum pH of an endodontic medicament is close as possible to that of body fluids, i.e., around 7.2 as higher and lower pH's are likely to cause cellular necrosis of tissues in direct contact with the medicament. This study investigated the pH of various endodontic medicaments commonly used in pediatric dentistry, both singly and in the various combinations available for clinical use. The results showed that the pH ranged from a low of 2.90 +/- 0.02 for iodoform paste (Kri) to a high of 12.45 +/- 0.02 for calcium hydroxide (Calyxl). Eugenol showed a pH of 4.34 +/- 0.05, formocresol 2.79 +/- 0.02, and a commercially-available antibiotic-corticosteroid paste (Ledermix) 8.13 +/- 0.01. Addition of up to 50 percent (v/v) of Ledermix or 25 percent Kri respectively did not affect the pH of Calyxl significantly. Although the addition of up to 75 percent Kri to Ledermix caused a fall in pH, the changes are probably not significant clinically. Furthermore, the addition of 50 percent eugenol to formocresol increased its pH significantly. The optimum pH of an endodontic medicament is as close as possible to that of body fluids, i.e., around 7.2. Higher and lower pH's are likely to cause cellular necrosis of tissues in direct contact with the medicament. However with the exception of calcium hydroxide there has been very little information available on the pH of endodontic medicaments commonly used in pediatric dentistry. Medicaments such as formocresol, eugenol and iodoform pastes have been extensively used for endodontic therapy yet very little attention has been given to their pH values.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcium Hydroxide↗
PubMed1989

Tryptamine alkaloid toxicosis in feedlot sheep.

Tryptamine alkaloid toxicosis (Phalaris staggers) was diagnosed in feedlot sheep. Clinical signs of toxicosis, which were exacerbated by excitement, included gait abnormalities, muscular tremors, nystagmus, and convulsions. An estimated 8% of the most severely affected lambs had clinical signs of toxicosis. Gross lesions detected in the brain of affected lambs consisted of focal gray-green discoloration in the brain stem and thalamus; these areas had microscopic evidence of intraneuronal pigment accumulation. Brain specimens obtained at slaughter indicated that 60% of the lambs had lesions consistent with tryptamine alkaloid toxicosis. Tryptamine alkaloids were found in low concentrations in the feed. Lambs exposed to these feeds had higher death losses than those that were not exposed to the feeds. Cobalt concentration in the feed was higher than that previously reported to be associated with Phalaris staggers.

Alkaloids↗
PubMed1989

The biochemical composition of venom from the pavement ant (Tetramorium caespitum L.).

The venom of the pavement ant, Tetramorium caespitum, is used for prey capture, defense and social communication. The venom is predominantly proteinaceous in nature and contains various free amino acids, predominantly aspartic and glutamic acid, as well as histamine. The activities of the enzymes phospholipase and hyaluronidase, which are believed to be present in all hymenopteran venoms could not be detected. The composition of Tetramorium caespitum venom is compared with other myrmicine venoms.

Amino Acids↗
PubMed1989

In vitro activity of CP-65,207, a new penem antimicrobial agent, in comparison with those of other agents.

CP-65,207 is a new parenteral penem antibiotic with a broad spectrum that includes gram-positive, gram-negative, and anaerobic microorganisms, with MICs for 90% (MIC90s) of the majority of 1,101 clinical pathogens tested being less than or equal to 1 microgram/ml. The compound was from 10- to 100-fold more active than cefoxitin and broad-spectrum cephalosporins against gram-positive bacteria and anaerobes. CP-65,207 was less active than imipenem for staphylococci, group A streptococci, and Enterococcus faecalis. Against members of the family Enterobacteriaceae, CP-65,207 was in general 100-fold more active than cefoxitin, 5- to 10-fold more active than broad-spectrum cephalosporins, and 2-fold more active than imipenem. Fresh clinical isolates that were resistant to broad-spectrum cephalosporins were highly susceptible to CP-65,207 and imipenem (MIC90, 1 microgram/ml). Isolates of Enterococcus faecalis, Serratia marcescens, and anaerobic Peptococcus spp. had MIC90s of 8, 2, and 3.12 micrograms/ml, respectively. CP-65,207 was not very active against methicillin-resistant staphylococci or Pseudomonas aeruginosa. Killing kinetics showed that against some strains CP-65,207 is rapidly bactericidal at concentrations well below those required to achieve a similar degree of killing with cefotaxime, ceftazidime, and ceftriaxone. CP-65,207 was only slightly susceptible to hydrolysis by type I cephalosporinases and TEM-1, SHV-1, and PSE-2 plasmid-encoded enzymes. It had the highest affinity for penicillin-binding proteins 2, 1A, 1B, and 3 in cell-free preparations of Escherichia coli W-7.

Anti-Bacterial Agents↗