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Biomedical subjects

A Williams

Publications and source records attributed to A Williams.

At least 649 records · Page 36Linked to original sources
PubMed1978

Bronchial atresia: a recognizable entity in the pediatric age group.

Bronchial atresia, a congenital lesion that develops after the 16th wk of fetal life, may be more common than previously believed, and this probably explains some cases of so-called congenital lobar emphysema. It may produce symptoms of pulmonary infection, wheezing, and respiratory distress severe enough to justify elective resection of that part of the lung distal to the atresia. The roentgenographic features that make this a recognizable entity are the following: (1) There is localized hyperinflation of lung in a segmental or lobar distribution, with a circular or oval parahilar radiodensity. Bronchography will demonstrate that there is no filling of the bronchus supplying this part of the lung. (2) The occasional neonate with this condition may present with an intrathoracic mass suggesting retained fetal lung fluid in lobar distribution. Bronchography will demonstrate that there is no filling of the bronchus to that part of the lung. (3) A plug of desquamated tissue and mucus in the cyst-like bronchus just distal to the point of atresia appears to be an unvarying component of the syndrome. It most commonly presents as a round or oval density, but in some cases it may be shaped like a rod or tree and rarely contains an air-fluid level.

Adolescent↗
PubMed1978

The surgical treatment of equinovarus deformity in adults with spasticity.

Adults with deformities of the lower limb due to spasticity may be considerably improved by operation, but thorough pre-operative assessment as an inpatient is essential in order to pinpoint the disability. The commonest deformity is equinovarus which often responds to simple operative procedures. The results of seventy-seven operative procedures in fifty patients are recorded. Correction once achieved is stable and the deformity does not recur.

Achilles Tendon↗
PubMed1978

Relaxation in heart muscle: some morphological and biochemical considerations.

In striated muscle the transition from the active to the resting state requires a reduction in the cytosolic concentration of ionized calcium (Ca2+), achieved by a rapid sequestration into the sarcoplasmic reticulum and the return of some Ca2+ to the extracellular phase. Morphologically the sarcoplasmic reticulum (SR) is heterogeneous. Specialized regions occur whenever the limiting membranes of the SR approach those of the plasmalemma. These specializations include a narrowed lumen, relative to that found in non-specialized parts of the SR, the presence of electron-dense 'feet' extending into the junctional gap separating the facing membranes of the plasmalemma and the SR, and the occurrence of intraluminal densities. These specializations can assume a variety of configurations, some of which appear to be species specific. The accumulation of Ca2+ by the SR, is a rapid process and the required energy is derived from the hydrolysis of ATP via a Ca2+-activated ATPase in the limiting membranes of the SR. Impaired relaxation in heart muscle can result either from an inadequate supply of ATP, Ca2+-overload, failure of the Ca2+-activated ATPase enzyme, leakage of Ca2+ from the SR, or the failure of the cell to return Ca2+ back into the extracellular phase. Evidence will be presented to show that the rise in resting tension that is caused by an inadequate supply of oxygen involves a mobilization of Ca2+ from the internal stores, and insufficient ATP to drive the ATPase enzyme in the SR, rather than a malfunction of the enzyme. Likewise ouabain-induced contractures have been found to be associated with diminished tissue stores of ATP, the rise in tissue Ca2+ occurring as a late phenomenon.

Adenosine Triphosphatases↗
PubMed1977

Late return of renal function after correction of chronic obstruction.

A 57-year-old man presented with renal failure secondary to bilateral interstitial nephritis and left hydronephrosis owing to a calculus in the renal pelvis, creatinine clearance being 2.4 cc per minute. Renal function did not improve after left pyelolithotomy and hemodialysis was instituted. No demonstrable change in renal function could be detected until 10 weeks postoperatively when creatinine clearance was 25 cc per minute.

Chronic Disease↗
PubMed1977

Lung mast cells in rats exposed to acute hypoxia, and chronic hypoxia with recovery.

Exposure to acute hypoxia (barometric pressure 263 mmHg) for 8 hours did not lead to increased numbers of mast cells in the lungs of rats. In contrast, in adult rats kept for 35 days at a barometric pressure of 380 mmHg there was a proliferation of mast cells around the pulmonary blood vessels and in the alveolar septa. This hyperplasia of lung mast cells in response to chronic hypoxia was reversible on removal of the hypoxic stimulus. There was a correlation between the logarithm of the perivascular lung mast cell density (defined in the paper) and the logarithm of the right ventricular weight. There was no increase in the mast cells in the carotid bodies of the hypoxic rats. Young male, old male, young female, and old female rats which had been subjected for 39 days to a barometric pressure of 380 mmHg showed a proliferation of mast cells around the pulmonary blood vessels and in the alveolar walls. This response was greatest in the adult animals and independent of their sex. In the age and sex experiment there was a correlation between the perivascular lung mast cell density and the medial thickness of the muscular pulmonary arteries. Since mast cell hyperplasia has been reported as preceding right ventricular hypertrophy, it is conceivable that mast cell proliferation in the lung may be a defence mechanism to limit the severity of hypoxic pulmonary hypertension rather than to mediate it.

Age Factors↗
PubMed1977

Polymeric albumin in the urine of patients with nephrotic syndrome.

Dimer and polymer albumin was detected in the urine of a proportion of pantients with a nephrotic syndrome. Most of it was present as S-S bonded dimer and polymer; co-polymers, however, with IgG and alpha (1) anti-trypsin could be demonstrated. It is suggested that albumin polymerizes after it has passed the glomerular membrane. Albumin dimer was associated mainly with minimal change disease and early membranous glomerulopathy in patients, who in general responded well to therapy.

Albumins↗