Biomedical subjects

B Zahn

Publications and source records attributed to B Zahn.

5 recordsLinked to original sources

PubMed1998

Progressive retropalatal narrowing preceding obstructive apnea.

Pharyngeal occlusion during obstructive apnea is thought to be an inspiratory-related event; however, occlusion also occurs in the absence of negative intrathoracic pressure. We hypothesized that inspiratory-related pharyngeal occlusion would be preceded by significant expiratory narrowing. Eight sleeping patients with obstructive apnea were studied. Pharyngeal caliber, airflow, and esophageal pressure (Pes) were simultaneously monitored during three to four consecutive breaths preceding occlusion (between 3 and 22 events were studied per subject). Relative changes in retropalatal airway cross-sectional area (CSA) were determined from fiberoptic images (five frames per second) normalized to the maximum CSA. During inspiration, CSA was significantly reduced only during the breath immediately preceding the apnea (Group mean CSA +/- SEM: 51 +/- 8% at the start of inspiration compared with 37 +/- 8% at midinspiration). During expiration, for all breaths there was an initial significant increase in CSA compared with the nadir CSA during the preceding inspiration (CSA: breath-3, 57 +/- 10% to 79 +/- 3%; breath-2, 59 +/- 8% to 76 +/- 4%; breath-1, 37 +/- 8% to 64 +/- 8%), followed by a significant narrowing at end-expiration compared with the peak CSA during that expiration (CSA: breath-3, 79 +/- 3% to 62 +/- 6%; breath-2, 76 +/- 4% to 50 +/- 10%; breath-1, 64 +/- 8% to 36 +/- 10%). Occlusion occurred at a pressure significantly less than that generated during the previous unoccluded breath (Pes: breath-1, -10.8 +/- 2.9 cm H2O; occlusion, -8.2 +/- 1.9 cm H2O). These results show that expiratory narrowing produced a significant reduction of CSA at end-expiration prior to obstructive apnea.

Adult↗

PubMed1989

Longitudinal IQ changes in fragile X males.

Previous studies have reported a drop of IQ in males with Martin-Bell or fragile X syndrome during childhood and adolescence. It is uncertain when and why this drop occurs and whether it affects all fragile X males. We have analyzed longitudinal IQ data on all 24 fragile X males who have been followed for at least 2 years through the Child Development Unit in Denver and who have been evaluated with a Stanford-Binet Form L-M assessment. A significant drop in IQ occurred for the group as a whole, but an individual z analysis demonstrated that only 7 of 24 had a significant decline in IQ. Visual inspection demonstrates an initial decline in IQ beginning in middle childhood and continuing through adolescence. We postulate that this drop occurs because of relatively greater weaknesses with abstract reasoning and higher symbolic language skills that are stressed in the cognitive testing of later childhood and adolescence.

Adult↗

PubMedDate not supplied

[Can premature birth rate be reduced by preventive cerclage? A retrospective statistical analysis on the effect and value of cerclage using the Bavarian Perinatal Survey 1978-1980].

There is no simple correlation between cerclage rates and premature birth-rates. This concludes that premature birth-rates cannot be reduced by extending the cerclage. In all comparable categories the premature birth-rate was higher in groups which used the cerclage than those ones which did not use the cerclage even though a) the risk of social economical premature birth-rates was reduced and b) care was intensified for pregnancy cases. Cerclage groups have a higher percentage of case history risks than the non-cerclage groups. There is a direct relationship between the social status and the premature births. The case history of premature birth risks cannot be reduced using the cerclage especially with women who have previously had 2 abortions or premature births. When placenta previa occurs the cerclage does not reduce premature births. In the case of cervix insufficiency and early labor the cerclage reduces the premature birth-rate. Extended prophylactic cerclage cannot be used to diminish premature births.

Cervix Uteri↗

PubMedDate not supplied

[Can by preventive cervix cerclage the premature birth rate in multiple pregnancy be reduced? A retrospective statistical analysis on effectiveness of cerclage using the Bavarian Perinatal Survey 1978-1980].

Through a retrospective statistical analyzation of 3081 multiple births with 907 cerclage of BPE from 1978-1980, among which included 77 multiple births and 61 Cerclage cases of the Amberg gynecology clinic, could be proved that the liberal use of prophylactic cerclages could not reduce the premature birth rate of multiple birth pregnancies.

Birth Weight↗

PubMedDate not supplied

[Do extended preventive indications for cervix cerclage increase labor complications? A statistical analysis on direct and indirect complications of cerclage using Bavarian perinatal data 1978-1980].

On the basis of 159.710 single pregnancies with 11.321 cerclages documented in the Bavarian Perinatal Survey of 1978-1980, with 2.676 single-child births, and 514 cerclages performed on the authors' own patients, possible complications of the extended indication for cerclage were determined as follows: The late abortion rate was not increased. Possibly because the group represented a negative selection, rupture of the membranes prior to labour, infant mortality due to infection, and premature labour were significantly more common in gravidae who had undergone cerclage. However, it was not possible to identify a causal connection between these and the cerclage operation. With regard to indirect complications there was an appreciable increase in the number of caesarean deliveries among cerclage patients, a slight increase in the number of cases in which labour lasted over 12 hours, and a significant increase in the number of lacerations of the cervix. There was no increase in the incidence of post-term births, malformations, stillbirths, or infantile acidosis among the children of patients who had undergone cerclage.

Abortion, Spontaneous↗