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Biomedical subjects

B Murphy

Publications and source records attributed to B Murphy.

At least 163 records · Page 9Linked to original sources
PubMed1980

Seasonal pattern in childhood viral lower respiratory tract infections in Melbourne.

Respiratory syncytial virus and parainfluenza viruses are the major pathogens in acute lower respiratory infection in infants and younger children. They show distinct seasonal patterns. An annual epidemic of respiratory syncytial virus infection is seen in Melbourne and this coincides with the coldest months of the year. Parainfluenza virus Type 1, the most frequent cause of laryngotracheobronchitis, occurs as an autumn epidemic every second year. Parainfluenza virus Types 2 and 3 are present most years and do not show a clear seasonal pattern.

Acute Disease↗
PubMed1980

Intraregional basis for sequential filling and emptying of the lung.

We studied the sequential pattern of lung filing by measuring the slope of the alveolar plateau in single breath helium washouts after inhaling a bolus at a lung volume (VI) equivalent to 20. 40, 60 and 80% of vital capacity (VC). In seated subjects, prone dogs, both with the chest intact and wide open, and individual canine lobes, slopes at VI = 20% VC were more positive than those at VI = 80% VC, indicating a "first in - last out' pattern. Furthermore the range of slopes, which reflects the magnitude of sequencing, was comparable in the four situations. We conclude that sequential filing and emptying of the lung has predominantly an intraregional basis. A two compartment optimization analysis using single exponential pressure-volume curves suggests that only a small proportion of the lung needs to behave differently to produce the sequencing observed in individual lobes.

Adult↗
PubMed1980

The incidence of pneumoconiosis, mesothelioma and other respiratory cancer in men engaged in mining and milling crocidolite in Western Australia.

Previous employees of a mining company, engaged in mining of crocidolite at Wittenoom Gorge in Western Australia between 1943 and 1966, have been traced to determine their incidence of asbestos-related diseases. Of 6200 male employees, 220 (3.5%) have developed pneumoconiosis and 26 have developed pleural mesothelioma. No cases of peritoneal mesothelioma have been identified. Prior to 1978, 60 men had died from respiratory cancer other than mesothelioma, compared with 38.25 expected from the mortality experience of all Western Australian males. The incidence of pneumoconiosis and mesothelioma and the mortality from other respiratory cancer all increased with duration of employment, interval from first employment, and level of occupational exposure, indicating a strong relationship between intensity of asbestos exposure and these diseases. The mortality ratio for respiratory cancer, excluding mesothelioma (1.57), was nearly twice that for all nonrespiratory causes of death, suggesting a two-fold increase in mortality from respiratory cancer compared with all Western Australian males. Variation of mortality from respiratory cancer by duration of employment and occupational exposure suggests that at least 30% of respiratory cancer deaths other than mesothelioma may be due to asbestos exposure. The major part of this excess is accounted for by respiratory cancer occurring in men with previously diagnosed pneumoconiosis.

Asbestos↗
PubMed1979

Influenza A and B virus infection in infants and young children during the years 1957-1976.

Influenza A virus activity was demonstrated in infants and young children from metropolitan Washington, DC during each of 19 successive August-July respiratory disease years, and during 17 of these years at least 2% of hospitalized respiratory disease patients yielded an influenza A or B virus and/or showed an influenza A or B serum complement-fixing (CF) antibody response. Between October 1957 and July 1976, 14.3% of 860 croup patients and 5.3% of a total of 5655 hospitalized respiratory patients, including croup patients, showed evidence of influenza A or B infection. The mean period of hospitalization with either virus was about 8 days, though serious infection with influenza A virus was 4.5 times more common than with influenza B virus. Both influenza viruses were detected more frequently in respiratory disease outpatients than in respiratory disease inpatients. Patients with serious influenza A virus infections were especially likely to have croup (particularly during the H3N2 era), to be seen during December through February, and to be black male infants. During the peak month of a composite of 13 consecutive influenza A virus outbreaks, influenza A virus infection was demonstrated in 67.6% of croup patients and in 35.6% of all hospitalized respiratory patients including croup patients. During the peak month of a composite of 6 consecutive influenza B virus outbreaks, influenza B virus infection was demonstrated in 36.0% of croup patients and in 10.8% of all hospitalized respiratory disease patients including croup patients.

Antibodies, Viral↗
PubMed1979

Metabolic sources of heat and power in tuna muscles. I. Muscle fine structure.

As part of an investigation into the generation of muscle heat in the tuna, the histochemistry and ultrastructure of the myotomal muscles were studied. Both red and white fibres are differentiated into two forms. The two forms of red muscle are very similar except for differential electron absorbance and different kinds of glycogen granules stored. In both forms, capillarity, mitochondrial numbers, and intracellular lipid droplets are abundant, implying the potential for a vigorous aerobic metabolism. During bursts of swimming, glycogen granules and intracellular lipid droplets are both largely depleted. The two types of white fibre differ in electron absorbance, pinocyotic activity, glycogen abundance, and insertion pattern, all of which are more pronounced in the 'dense' fibre form. Several features of tuna white muscle are unique or unusually developed. Thus, tuna muscle contains more glycogen than does red muscle. Glycogen granules may be randomly dispersed in myofibrillar or peripheral regions or may be sequestered in membrane-bound structures termed glycogen bodies. During short bursts of swimming, glycogen granules from all storage sites are mobilized. The white muscle has an ample capillary supply, small, but significant, amounts of intracellular lipid, and unusual numbers of mitochondria.

Animals↗
PubMed1978

Flow dependence of gas distribution and the pattern of inspiratory muscle contraction.

We measured regional distribution of xenon-133 boli at 0.25, 0.75, and 1.5 l/s in four normal seated subjects during inspirations performed predominantly with intercostal and accessory muscles (IC) or with the diaphragm, accompanied by outward abdominal motion (Ab). In six additional subjects we inferred the topographical distribution of helium boli during similar breaths and flow rates from the slope of the alveolar plateau recorded during a slow expiration (less than 0.5 l/s). Distribution of the helium boli was studied during natural as well as IC and Ab inspirations. At each of the flow rates IC breaths distributed relatively more of the inspired bolus to upper lung regions than did Ab inspirations. Natural breaths at 0.25 l/s resulted in distributions similar to those of Ab inspirations, whereas at 1.5 l/s the distribution approached that of IC inspirations. A three-compartment model, representing upper, middle, and lower lung regions, was used to simulate bolus distribution. The experimental data showed substantial departure from predictions based on regional time constants alone. However, additional small differences in applied pressure (less than 0.50 cmH2O) between the regions satisfactorily accounted for the gas distribution.

Abdominal Muscles↗