Biomedical subjects

L D Montgomery

Publications and source records attributed to L D Montgomery.

39 records · Page 3Linked to original sources

PubMedDate not supplied

Amniotic septostomy for the treatment of twin oligohydramnios-polyhydramnios sequence.

OBJECTIVE: To report our experience with intentional puncture of the intervening membrane ('septostomy') for the treatment of the twin oligohydramnios-polyhydramnios sequence (TOPS). METHODS: 12 patients were diagnosed with TOPS based on ultrasonographic findings. A 20- to 22-gauge spinal needle was used to puncture the membrane between the twins without any attempt at amnioreduction in 9 patients, while the procedure was combined with amnioreductions in 3 patients. RESULTS: Gestational age was 23.1 +/- 3.3 weeks at the time of septostomy and 31.1 +/- 4.4 weeks at delivery. Rapid accumulation of fluid around the 'stuck' fetus occurred in all cases following a single procedure. Three of the 24 fetuses died in utero and 1 died on the fifth day of life, for a combined survival of 83.3%. In the survivors, the septostomy to delivery interval ranged between 0.6 and 13 weeks (mean +/- SD 8.3 +/- 4.8). CONCLUSION: Amniotic septostomy is a promising new method for the management of TOPS and is associated with survival rates that are better than, or comparable to, more invasive modalities. A multicenter trial comparing septostomy to other modalities is warranted.

Amnion↗

PubMedDate not supplied

Iatrogenic gastroschisis decreases pulmonary hypoplasia in an ovine congenital diaphragmatic hernia model.

Pulmonary hypoplasia is a major problem in infants with congenital diaphragmatic hernia. Intrauterine reparative procedures are associated with a high complication rate. The development of less complex operations to reduce the degree of fetal lung hypoplasia may improve neonatal survival. Our objective was to investigate the effectiveness of an iatrogenic gastroschisis in reducing fetal pulmonary hypoplasia in a sheep model with an artificially created diaphragmatic hernia. A left-sided diaphragmatic hernia (Bochdalek type) was created at 75 days' gestation in an ovine fetal model during the pseudoglandular phase of lung development. At 110 days' gestational age, a left-sided gastroschisis was created by excising part of the lower abdominal wall and buttressing the opening with a rubber ring. The fetus remained in utero until 135 days' gestation, at which time it was sacrificed for autopsy. Histopathologic and morphometric studies were performed on the lungs. Ten animals had creation of a diaphragmatic hernia. Four underwent the second surgery to create a gastroschisis. One animal completed the entire protocol, 3 fetuses aborted after the second surgery. Autopsy confirmed effective decompression of the herniated abdominal contents from the chest into the amniotic cavity in all 4 cases. The lungs of the animal that completed the protocol were appropriately developed, while those fetuses that died soon after gastroschisis creation had severe pulmonary hypoplasia, mainly involving the left lung. Artificially induced diaphragmatic hernia, in the ovine fetus, causes severe pulmonary hypoplasia.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdominal Muscles↗

PubMedDate not supplied

Electroencephalographic scalp-energy analysis as a tool for investigation of cognitive performance.

In a new method of using electroencephalography (EEG) to monitor cognitive events, multichannel event-related potentials (ERPs) were used to estimate scalp distributions of surface energy densities of cortically generated electrical fields. Cross-subject regression analyses were then used to map sites and post-stimulus latencies, for which there is a high correlation of energy densities with subjects' performances. In a preliminary study, five right-handed young men were presented mental arithmetic tasks via a computer screen. A 21-channel ERP was computed for each subject and converted to show the scalp distribution of energy density at each sampling period (every 7.8 msec). Indices of subjects' task performances were regressed upon these estimates of potential energy at each electrode site and post-stimulus latency. High correlations were found at four distinct regions and latencies. These corresponded to the stages and sites of cortical localization for mental arithmetic inferred from studies of patients with localized cortical lesions. This correspondence suggests that the EEG procedure may offer an inexpensive, noninvasive method of investigating cortical localization of cognitive function in healthy subjects.

Adult↗