Postnatal white matter necrosis in preterm infants.

One hundred twenty-seven infants less than 36 weeks of gestation (mean +/- SE = 31 +/- 3.2 weeks) were studied with echoencephalography to determine the incidence and complications associated with white matter necrosis. Ten infants (8%) developed cysts ten or more days after birth, indicating postnatal onset of white matter necrosis. Univariate analysis showed that postnatal white matter necrosis was significantly associated with maternal infection (other than urinary infection), respiratory distress syndrome, and longer requirement of an oxygen concentration greater than 40%. Forward logistic regression analysis showed postnatal white matter necrosis to be associated with maternal infection, chronic placental infarction, congenital pneumonia, and longer requirement of an oxygen concentration greater than 40%. Neurodevelopmental outcome was abnormal during infancy in 4 of the 6 survivors with postnatal white matter necrosis. Severe respiratory disease and maternal and/or fetal infection appear to increase the risk of the immature brain to white matter necrosis, predisposing the infants to subsequent neurodevelopmental delay.     

Ten-year trends in neonatal assisted ventilation of very low-birthweight infants.

OBJECTIVES: To examine ventilatory support for the VLBW infant over the past 10 years in a single academic NICU and determine factors that predicted length of ventilation, death, and CLD. STUDY DESIGN: A retrospective cohort review of neonatal blood gases, ventilatory support, and clinical outcomes. RESULTS: From 1992 through October 2002, 6254 infants were admitted, of whom 2388 required intubation for mechanical ventilation. Of these, 837 were <1500 g at birth (VLBW) infants and 453 were less than 1000 g (ELBW). Total duration of ventilation decreased in all weight groups. Noninvasive ventilatory support increased from 20 to 55% of total ventilation from 1997 to 2002. During this same period, CLD decreased from 20 to 11% in ventilated VLBW infants. Duration of total ventilation was best predicted by birth weight, with each 100 g increment decreasing the duration of ventilation by 71 hours. Lower birth weight, male sex, and a longer total duration of ventilatory support were significant factors in predicting the occurrence of CLD. Death alone was best predicted by lower birth weight and maximum oxygen index (OI). Transported infants had significantly increased maximal OIs, durations of ventilation, and incidence of death. A total of 48% of infants with a single OI >10 either died or survived with CLD. CONCLUSIONS: Birth weight is the best predictor of duration of ventilation, and CLD is best predicted by birth weight, duration of ventilation and male sex. The increasing use of noninvasive strategies has not been associated with an observable increase in respiratory morbidity. VLBW infants with a single OI>10 may benefit from inclusion in future interventional rescue studies.     

Estrogen effects on object memory and cholinergic receptors in young and old female mice.

We investigated whether object recognition memory is modulated by estrogen in young (5 month) and aged (24 month) female C57Bl/6J mice, and if cholinergic muscarinic receptors might contribute to this response. Mice that were ovariectomized, or ovariectomized plus estradiol-treated three weeks before behavioral testing or quantitative autoradiography were compared to intact mice. Memory for a previously encountered object deteriorated significantly between 3 and 6h after initial exposure, regardless of animal age. In both young and aged mice, estradiol-treated mice showed significantly greater recall than did ovariectomized mice. In both age groups, the apparent number of [(3)H]pirenzepine/M(1)-like and [(3)H]AFDX384/M(2)-like muscarinic receptor binding sites was reduced in the basal forebrain as well as its projection areas following ovariectomy, but this decrease was not alleviated by estrogen. Aging poorly affected object memory, but reduced muscarinic binding in some cortical subregions and in the caudate nucleus. These findings suggest that estrogen effects on memory in C57Bl/6J mice are not due to changes in the number of muscarinic receptors.     

Acetylcholine release is elicited in the visual cortex, but not in the prefrontal cortex, by patterned visual stimulation: a dual in vivo microdialysis study with functional correlates in the rat brain

By its projections to the primary visual and the prefrontal cortices, the basal forebrain cholinergic system is involved in cognitive processing of sensory stimuli. It has been suggested that visual stimulus-induced cholinergic activation of the visual cortex may exert a permissive role on thalamocortical inputs. However, it is not known if visual stimulation elicits cholinergic activation of high-order brain areas in the absence of attentional need. In the present study, we measured the effects of patterned visual stimulation (horizontal grating) on the release of acetylcholine with dual-probe in vivo microdialysis in the visual and the prefrontal cortices of anesthetized rats. We also used retrograde tracing to determine the anatomical relationships of cholinergic neurons with neurons of the visual system and the prefrontal cortex. Finally, we evaluated a functional correlate of this stimulation, namely c-fos immunolabeling. Patterned visual stimulation elicited significant increases in acetylcholine release in the visual cortex, accompanied by an increased number of c-fos immunoreactive neurons in this brain area. In contrast, in the prefrontal cortex, neither the level of acetylcholine release nor the number of c-fos immunoreactive neurons was significantly changed because of the stimulation. Cholinergic basal forebrain neurons projecting to the visual or the prefrontal cortices were both localized within the horizontal limb of the diagonal band of Broca but were not immunoreactive for c-fos during visual stimulation. No parts of the visual system were found to directly project to these basal forebrain neurons. These results suggest the differential involvement of cholinergic projections in the integration of sensory stimuli, depending on the level of activity of the targeted cortical area.     

Major lower limb amputations in the elderly observed over ten years: the role of diabetes and peripheral arterial disease

BACKGROUND: Major amputation is a dreaded event with high mortality and morbidity. However, few studies have investigated the epidemiology of amputation in the elderly over time, in the face of evolving management and prevention efforts. METHODS: We undertook a retrospective study to determine the incidence rate, etiology and prognosis of major lower limb amputations (transtibial or higher) in elderly patients (> 65 years). Cases were identified over a 10-year period in the Geneva (Switzerland) area, where all amputations are performed in a single center and reliable demographic data are available. RESULTS: The rate of amputation varied from 1.8 to 11.4/10000 patients/year, increasing with age and male gender. Diabetes was present in 48% patients, and conferred a 10 times higher risk of amputation. Severe peripheral arterial disease (PAD) was present in > 94% patients. The prognosis remains poor, 47% patients had died after two years and only 53% patients could be equipped with a prosthetic limb. Over 10 years we found a progressive increase in age at amputation; this encouraging increase was mostly accounted for by diabetic patients (> 6 months per year). CONCLUSIONS: The rate of amputation observed among elderly patients was low. Neither the rate nor the prognosis improved over the decade studied. However, the age at amputation increased by > 6 months/year, particularly in diabetic amputees, suggesting that current management successfully delays amputation. Amputations were almost exclusively performed for severe PAD. Further reduction in the rate of amputation will require progress in the prevention and management of PAD.     

Total knee arthroplasty of the stiff knee: three hundred and four cases

Purpose

The purpose of this study was to analyse the results of total knee arthroplasty (TKA) in stiff knees (flexion ≤90° and/or flexion contracture ≥20°). Our hypothesis was that despite having poorer results than those obtained in a “standard” population and a high rate of complications, TKA was a satisfactory treatment in patients with osteoarthritis of the knee associated with significant stiffness.

Methods

Three hundred and four consecutive primary HLS TKAs (Tornier), whose data were prospectively collected between October 1987 and October 2012, were retrospectively analysed at a mean of 60 months (range, 12–239) postoperatively. Two groups, those with a “flexion contracture” and those with a “flexion deficit”, were assessed for postoperative range of motion (as integrated to the Knee Society score [KSS]), physical activity level and patient satisfaction.

Results

At the latest follow-up, range of motion was significantly improved, as was the KSS. Ninety-four percent of patients were satisfied or very satisfied, and activity levels were increased after surgery. The complication rate, however, was high in patients with a preoperative flexion deficit (17 %). Pain and residual stiffness were the most common complications.

Conclusion

TKA provides satisfactory results in patients with knee osteoarthritis associated with significant pre-operative stiffness. The surgical plan should be adapted to anticipate complications, which are particularly frequent in the presence of a flexion deficit.