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Biomedical subjects

M Collins

Publications and source records attributed to M Collins.

At least 343 records · Page 19Linked to original sources
PubMed1981

Expression of the ribosomal DNA insertions in bobbed mutants of Drosophila melanogaster.

We have shown earlier that interrupted rRNA genes in Drosophila melanogaster do not contribute significantly to rRNA production by a splicing mechanism (Long and Dawid 1979). In the work reported here the expression of interrupted rRNA genes was tested in several stocks that carry bobbed mutations, i.e., have partial deletions of their rRNA gene clusters. Transcripts of the major 5 kb type 1 insertion are very rare in bobbed flies as they are in the wild type, occurring at a concentration in embryos of less than one copy per nucleus. Transcripts of short type 1 insertions are more abundant in certain bobbed stocks, especially those carrying the car bb chromosome. However, other severely bobbed flies have no increase in these insertion transcripts over the wild-type levels. Type 2 insertions are transcribed into very rare RNA molecules in the wild type and in the bobbed genotypes that were studied. From these results we conclude that interrupted rRNA genes are not expressed through a splicing mechanism into mature rRNA in mutant or wild-type flies. Since even severely bobbed flies fail to utilize their interrupted rRNA genes, we suggest that these genes cannot be transcribed productively in D. melanogaster.

Animals↗
PubMed1981

Electrocardiographic poor R-wave progression. Correlation with postmortem findings.

Electrocardiographic criteria have been derived from vectorcardiographic and angiographic correlation which allow division of patients with electrocardiographic "poor R-wave progression" or "reversed R-wave progression" into the following four etiologic groups: (1) anterior myocardial infarction; (2) left ventricular hypertrophy; (3) type-C right ventricular hypertrophy; and (4) the normal variant. The sensitivity, specificity, and predictive value of this approach to the electrocardiogram with poor or reversed R-wave progression were studied in a series of 33 patients examined at autopsy. Using the scheme and criteria outlined, 85 percent (11/13) of the pathologic anterior myocardial infarctions were correctly diagnosed. The electrocardiographic criteria correctly identified 75 percent (15) of 20 patients with poor or reversed R-wave progression without postmortem evidence of myocardial infarction, with only 12 percent (2/17) predictive error. The relative risk of autopsy-documented anterior myocardial infarction in patients meeting the specified electrocardiographic criteria was six times that of other patients with poor or reversed R-wave progression.

Cardiomegaly↗
PubMed1981

The effect of protein deficiency on the development of chronic antigen-antibody complex disease in mice.

Mice genetically selected to produce antibodies of either high or low affinity to protein antigens injected in saline were fed either a normal protein diet or a protein-deficient diet and were given daily injections of HSA for up to 73 days to induce chronic antigen-antibody complex disease. In low-affinity mice fed the normal protein diet, this resulted in impairment of renal function, deposition of immunoglobulin, C3 and HSA in the glomeruli, high levels of circulating antigen-antibody complexes and death from apparent renal failure in 50% of the animals. High-affinity mice on either diet had no impairment of renal function, fewer deposits in the glomeruli, lower levels of circulating complexes and no deaths. Low-affinity mice fed the protein-deficient diet had less impairment of renal function and less glomerular deposition of complexes than did low-affinity mice fed the normal diet. In addition, none of these mice died from renal failure. These results demonstrate that the protein-deficient diet reduced the severity of the experimental chronic antigen-antibody complex disease in low affinity mice but did not increase the susceptibility of high-affinity mice to the disease.

Animals↗
PubMed1980

The growth of Hymenolepis microstoma in intact and gonadectomized mice.

Gonadectomy or sex of the host had no effect on the mean dry weight of Hymenolepis microstoma examined on day 12 postinfection (p.i.). However, on day 20 p.i. worms from intact or sham-operated male mice were significantly heavier than those recovered from the corresponding groups of female hosts. Orchiectomy of hosts lowered the average weight of these older worms, but ovariectomy had no effect.

Animals↗
PubMed1980

Statistical prediction of change in aphasia.

We reviewed speech, language, and biographical data on 144 asphasic patients who had suffered left hemisphere cerebral vascular accidents. Using a step-wise multiple regression procedure, we attempted to predict change in severity of aphasia at three, six, and 12 months postonset based on performance at one, three, and six months postonset. Our results suggest statistical prediction of change is feasible. Multiple correlation coefficients ranged from 0.74 to 0.94.

Adolescent↗
PubMed1980

Metabolic and cardiovascular side effects of the beta 2-adrenoceptor agonists salbutamol and rimiterol.

The metabolic and cardiovascular side-effects of intravenous infusions of therapeutic doses of beta 2-adrenoceptor agonists salbutamol and rimiterol have been determined in four healthy male subjects. There were dose-related increases in plasma glucose, renin activity, serum insulin and heart rate, and significant hyperlactataemia and ketonaemia. There were dose-related decreases in plasma potassium, phosphate and corticosteroids and significant hypocalcaemia and hypomagnesaemia. The effects of equivalent molar amounts of salbutamol and rimiterol were similar. Whichever drug is used, special care is required with patients who may have abnormal glucose tolerance, potassium depletion, or be predisposed to lactic acidosis. Rimiterol may be preferable for infusion because of its short plasma half-life.

Albuterol↗
PubMed1979

Breathing, pausing and reading.

An analysis of the breathing patterns of speakers in a variable-rate reading task shows that the duration and frequency of breathing pauses are dependent both on the rate of speaking and the syntactic nature of the pause location. Non-breathing pauses follow the same pattern of occurrence as breathing pauses, but are always shorter and tend to occur primarily at minor constituent breaks. At slow and normal rates, speakers accommodate their need to inhale to the preplanned pause patterns. At fast rates, however, the physiological need to breathe is the sole determinant of pausing.

Female↗
PubMed1978

Algal toxins.

Explore the source record for details and available documents.

Journal Article↗
PubMed1977

Right-hemisphere language dominance in a case of left-hemisphere arteriovenous malformation.

This paper reports a case of surgical removal of a left-hemisphere arteriovenous malformation (AVM) in a left-handed adult without subsequent speech or language deficit. Preoperative intracarotid amobarbital testing indicated right-hemisphere language dominance. Our patient demonstrated no language involvement prior to or following surgery. We speculate the congenital nature of a left-hemisphere AVM may dictate right-hemisphere language dominance, thereby explaining the lack of residuals following removal of AVMs in left-hemisphere speech and motor areas.

Adult↗
PubMed1973

Effects of lysozyme and chitinase on the spherules of Coccidioides immitis in vitro.

Spherules of Coccidioides immitis strain Silveira produced in vitro were treated with chitinase and lysozyme. The walls of merthiolate-killed mature endosporulating spherules were degraded by chitinase (500 mug/ml) and by lysozyme (100 and 500 mug/ml). Thus, as was visible through the light microscope, the spherule wall was reduced in thickness from 1 to 2 mum to less than 0.5 mum. The degradation was evident also by release of N-acetylglucosamine, three times as much N-acetylglucosamine being released by chitinase in 12 h as was released by lysozyme in 3 days. However, the effect of lysozyme on living mature spherules was in marked contrast to the effect of chitinase in that treatment with lysozyme led to marked reduction in viability. Exposure to lysozyme (500 mug/ml) for 48 h permitted survival of only 0 to 0.2% of spherules. Thinning of the walls was observed only in the larger spherules (25-35 mum) treated with lysozyme. By contrast, chitinase (500 mug/ml) led to complete dissolution of the walls of living mature spherules but the viability of the liberated endospores was unaffected during contact with chitinase for 48 h. Living non-endosporulating immature spherules and free endospores were also rendered nonviable by lysozyme but not by chitinase.

Cell Survival↗