Hippocampal volumes and cognitive performance in children born extremely preterm with and without low-grade intraventricular haemorrhage

Children born extremely preterm, especially those with intraventricular haemorrhage (IVH), are at increased risk of adverse cognitive outcomes during childhood. The present study aimed to explore the effects of IVH (grades I-II) on hippocampal volumes, and their correlates with cognitive performance. The sample consisted of 94 participants, including 54 children born extremely preterm (19 with IVH, grades I-II), and 40 children born at term. All participants underwent a magnetic resonance imaging study at the age of 10 (M_age = 10.20 years; SD_age = 0.78), and 74 of them (45 extremely preterm and 29 full-term) carried out a cognitive assessment at 12 years old. Children born extremely preterm had lower scores in cognitive performance compared to their full-term peers. Significant positive partial correlations were observed between global bilateral hippocampus, left CA-field, and left subiculum volumes with processing speed in the full-term group, while no significant correlations were found in the extremely preterm group. Moderation analyses in the extremely preterm sample revealed that low-grade IVH moderated the relationship between right hippocampal volume and full-IQ (F_{(4,40) =} 5.42, p = 0.001, R² = 0.35). Having greater right hippocampal volume had a protective effect on full-IQ in those children born extremely preterm with low-grade IVH.

Destruction Rate of H3+ by Low-Energy Electrons Measured in a Storage-Ring Experiment

Knowledge of the abundance of H(3)(+) is needed in interstellar and planetary atmospheric chemistry. An important destruction mechanism of H(3)(+) is low-energy electron impact followed by dissociation, but estimates of the reaction rate span several orders of magnitude. As an attempt to resolve this uncertainty, the cross section for dissociative recombination of vibrationally cold H(3)(+) has been measured with an ion storage ring down to collision energies below 1 millielectron volt. A rate coefficient of 1.15 x 10(-7) cubic centimeters per second at 300 kelvin was deduced. The cross section scaled with collision energy according to E(-1.15), giving thee rate a temperature dependence of T(-0.65).

Preoperative short-term radiotherapy in rectal carcinoma. A preliminary report of a prospective randomized study

Between 1980 and 1983, 373 patients with clinically resectable rectal adenocarcinoma entered a prospective randomized study aimed to evaluate the effect of short-term preoperative radiotherapy. Protocol violations were identified in 21 instances. Of the remaining 352 patients, 182 were randomized to surgical treatment only (S-group). Immediately, before surgery, 170 patients were irradiated to the pelvic region with 25 Gy (2500 rad) during a 5-day period (RT-group). Of these patients, 59% underwent abdominoperineal excision, 38% anterior resection, and 3% laparotomy only. At surgery distant metastases were discovered in 32 patients (9%). There were no significant differences between the groups in the distribution of age, sex, operative methods, and tumor stage according to the original Dukes' classification. During the follow-up time, ranging between 6 months and 3 years, tumor recurrence occurred in 35 patients, 19 in the S-group and 16 in the RT-group. Fifteen patients in the S-group had pelvic recurrence compared to 10 patients in the RT-group. Distant metastases occurred in six and eight patients, respectively. Two patients in each group had both pelvic and distant recurrence. There was no correlation between tumor recurrence and type of operation. Median time interval from diagnosis to pelvic recurrence was 10 months in the S-group and 16 months in the RT-group. Postoperative complications in the form of wound sepsis were slightly more common in the RT-group. In summary, the applied treatment regimen, is well-tolerated and apparently does not affect the Dukes' stage of the tumor. Although there is no statistically significant difference, there is a trend of less pelvic recurrence in patients receiving preoperative radiotherapy.