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Biomedical subjects

L Landau

Publications and source records attributed to L Landau.

31 records · Page 2Linked to original sources
PubMed1977

Peripheral iridectomy in closed angle glaucoma-- late complications.

Of 70 eyes with therapeutic peripheral iridectomy (PI), 51% suffered a loss of two or more lines on the Snellen chart; 57% developed posterior synechiae (PS) and 57% showed lens opacities. Thirty-three per cent of eyes that underwent PI prophylactically had a vision drop of two lines or more, 39% developed PS and 42% showed varying degrees of lens opacities. Although vision drop, lens opacities and PS were less marked in the prophylactic group, it appears that PI is a surgical procedure not without its hazards. We therefore suggest that peripheral iridectomy should not be performed routinely on the second eye not suffering an acute attack. This procedure should be undertaken only in cases with positive provocative tests and/or clinical signs of closed angle glaucoma.

Adult↗
PubMed1976

Hemoglobin Beth Israel. A mutant causing clinically apparent cyanosis.

We found that an abnormal hemoglobin with a very low oxygen affinity was responsible for overt cyanosis in an otherwise healthy adolescent. Hemoglobin Beth Israel, in which serine replaces the asparagine residue normally present at position 102 (G4) of the beta-polypeptide chain, was associated with normal blood counts and no apparent exercise intolerance in the heterozygous carrier. Cyanosis resulted from a drastically right-shifted oxygen dissociation curve, whose position and shape could account for the absence of "physiologic" anemia. The whole-blood oxygen tension at 50 per cent oxygen saturation was 88 mm Hg (normally 26 +/- 1 mm Hg), and the arterial blood was only 63 per cent saturated with oxygen despite a normal oxygen tension of 97 mm Hg. The hemolysate showed a low oxygen affinity but normal Bohr effect. Unexplained cyanosis, particularly in association with normal arterial oxygen tension should prompt a search for an abnormal hemoglobin, which may obviate the need for invasive diagnostic procedures.

Adolescent↗
PubMed1976

Influence of bronchomotor tone on regional ventilation distribution at residual volume.

We studied the topographical distribution of 133Xe boluses inhaled slowly from RV, as well as the distribution of regional volumes at RV (RVr) in seven seated normal subjects before and after aerosolized isoprenaline (ISO) and after aerosolized methacholine hydrochloride (Mech). After Mech the ratio of inhaled 133Xe in the upper lung regions to that in lower lung regions (U/L) decreased from 3.21 +/- .33 (mean +/- 1 SE) to 1.27 +/- 0.12 (P less than 0.001) and returned to 3.89 +/- 0.55 after Iso. Iso alone increased U/L from 3.23 +/- 0.47 to 5.49 +/- 0.85 (P less than 0.025). The height of phase IV in expired 133Xe vs. volume plots correlated with U/L, being greater after Iso and smaller after Mech in each subject. The difference in RVr between upper and lower lung regions decreased after Mech in four out of five subjects from 0.22 TLC to 0.11 TLC. Iso alone did not change the gradient of RVr. The results are consistent with the concept that increased bronchomotor tone widens the range of critical opening and closing pressures with a more patchy and extensive distribution of airway closure.

Adult↗
PubMed1976

Influence of posture on flow dependence of distribution of inhaled 133Xe boli.

The second 100 ml of gas inspired at constant flow rates (V) from 0.1 to 2.5 l/s was tagged with 133Xe to determine the apicobasal bolus distribution ratio (VAlvA/VAlvB) for seven normal subjects in both the upright and supine postures. Gas was preferentially distributed to the base at low V. As V increased, redistribution to the apex occurred but was greater in the supine posture. As apicobasal time constant differences should be minimal in the supine posture, the greater flow dependence of bolus distribution suggests that the pressure swing was greater over apical zones than basal zones. Model studies indicate that the pressure differences (deltaPd) necessary to predict the measured VAlvA/VAlvB at all flow rates are less than 1.0 cmH2O. Such sensitivity of gas distribution to deltaPd at both low and high flow rates makes it appear relatively insensitive to regional compliance and resistance.

Adult↗
PubMedDate not supplied

Bilateral acute dacryocystitis in a premature infant.

A premature infant with bilateral acute purulent dacryocystitis was presented. The possibility of a contamination before delivery was raised. Treatment with antibiotics proved to be helpful in curing the disease.

Anti-Bacterial Agents↗