Intellectual disability in children aged less than seven years born moderately and late preterm compared with very preterm and term-born children - a nationwide birth cohort study

BACKGROUND

Prematurity has been shown to be associated with an increased risk of intellectual disability (ID).

METHOD

The aim was to establish whether the prevalence of ID, defined as significant limitations in both intellectual (intelligence quotient below 70) and adaptive functioning among moderately preterm (MP; 32⁺⁰ -33⁺⁶  weeks) and late preterm (LP; 34⁺⁰ -36⁺⁶  weeks) infants, is increased compared with that in term infants (≥37⁺⁰  weeks). Antenatal and neonatal risk factors for ID among gestational age groups were sought. The national register study included all live-born infants in Finland in 1991-2008, excluding those who died before one year age, or had any major congenital anomaly or missing data. A total of 1 018 256 infants (98.0%) were analysed: very preterm (VP; <32⁺⁰  weeks, n = 6329), MP (n = 6796), LP (n = 39 928) and term (n = 965 203).

RESULTS

By the age of seven years, the prevalence of ID was 2.48% in the VP group, 0.81% in the MP group, 0.55% in the LP group and 0.35% in the term group. Intracranial haemorrhage increased the ID risk in all groups. Male sex and born small for gestational age predicted an increased risk in all but the MP group.

CONCLUSIONS

The prevalence of ID decreased with increasing gestational age. Prevention of intracranial haemorrhages may have a beneficial effect on the neurodevelopmental outcomes of neonates.

Preoperative postural control of patients with vestibular schwannoma assessed by visual feedback posturography

BACKGROUND

The need for an objective method to describe the functional postural control of patients with vestibular schwannoma in agreement with their subjective sensation of balance.

OBJECTIVES

The objective was to compare the postural control of 49 patients with unilateral vestibular schwannoma (VS) with that of healthy subjects by using visual feedback posturography (VFP). We aimed to find out if preoperative postural control of the patients correlates with their subjective sensation of balance.

METHODS

In the VFP, while standing on the platform, patients were instructed to move their center of gravity (COG) marker to the targets as fast and accurately as possible. Hit delay (HD) to the targets, hold percentage (HP) within the targets, COG marker velocity (CMV) to the targets, and balance index (BI) were calculated. We rated intensity of balance disturbance using a 5-point qualitative scale.

RESULTS

Twenty-two (45%) patients had at least one abnormal VFP parameter, and 49% of patients were simultaneously symptomatic. Mean hit delay (HD), hold percentage (HP), and balance index (BI) were significantly worsened in patients with VS (p < 0.05). Increased HD and BI correlated significantly with subjective sensation of imbalance (p = 0.02).

CONCLUSIONS

The overall deficit in preoperative postural control of the VS patients was not severe, and this finding agreed well with their subjective sensations.

Biomechanics of slips

The biomechanics of slips are an important component in the prevention of fall-related injuries. The purpose of this paper is to review the available literature on the biomechanics of gait relevant to slips. This knowledge can be used to develop slip resistance testing methodologies and to determine critical differences in human behaviour between slips leading to recovery and those resulting in falls. Ground reaction forces at the shoe-floor interface have been extensively studied and are probably the most critical biomechanical factor in slips. The ratio of the shear to normal foot forces generated during gait, known as the required coefficient of friction (RCOF) during normal locomotion on dry surfaces or 'friction used/achievable' during slips, has been one biomechanical variable most closely associated with the measured frictional properties of the shoe/floor interface (usually the coefficient of friction or COF). Other biomechanical factors that also play an important role are the kinematics of the foot at heel contact and human responses to slipping perturbations, often evident in the moments generated at the lower extremity joints and postural adaptations. In addition, it must be realized that the biomechanics are dependent upon the capabilities of the postural control system, the mental set of the individual, and the perception of the environment, particularly, the danger of slipping. The focus of this paper is to review what is known regarding the kinematics and kinetics of walking on surfaces under a variety of environmental conditions. Finally, we discuss future biomechanical research needs to help to improve walkway-friction measurements and safety.

Development of a portable test device for assessing on-site floor slipperiness: an interim report

The main objective was to design and construct a prototype portable slipmeter with the capability of measuring static, transitional kinetic and steady-state kinetic coefficient of friction properties of on-site floors. The second objective was to evaluate its operation in the laboratory, using a commercial force platform as reference. The prototype was found to be capable of measuring the described frictional characteristics of floor surfaces, using three different test wheels and two modes of operation, impact and non-impact testing. The results anticipate that the slipmeter may prove to be more valid than any traditional measurement technique. The study continues with biomechanical trials and will be completed during the year 2000.

Cast treatment and intramedullary locking nailing for simple and spiral wedge tibial shaft fractures--a cost benefit analysis

BACKGROUND AND AIMS

The aim of this retrospective study was to compare the relative costs of treating simple and spiral wedge (requiring closed reduction under anaesthesia) tibial shaft fractures in a plaster cast or with intramedullary locking nail.

MATERIAL AND METHODS

The material consisted of 26 fractures treated in a plaster cast and 51 fractures treated with an intramedullary locking nail. The costs caused by the direct costs (treatment, hospitalisation, and outpatient appointments) as well as indirect costs (lost productivity) were taken into account. Costs caused by complications were also included in the analysis.

RESULTS

Mean direct costs per patient were FIM 22920 and FIM 26952 and mean overall costs per patient were FIM 120486 and FIM 82224 in plaster cast and intramedullary locking nailing groups, respectively (FIM 1 = USD 0.19). The higher mean overall costs of the plaster cast group were attributable to the longer sick leave periods in this group (218 days in plaster cast group and 124 in intramedullary nailing group).

CONCLUSION

Plaster cast treatment of simple and spiral wedge tibial shaft fractures requiring closed reduction under anaesthesia is more expensive to society than operative treatment with intramedullary locking nail.

Inflammatory responses in RAW264.7 macrophages caused by mycobacteria isolated from moldy houses

Mycobacterial strains (nonpathogenic Mycobacterium terrae, potentially pathogenic Mycobacterium avium-complex and Mycobacterium scrofulaceum), isolated from a moldy building, were studied with respect to their ability to stimulate macrophages (RAW264.7) to produce inflammatory mediators, and to cause cytotoxicity. Reactive oxygen species (ROS) were measured by chemiluminescence, cytokines (TNF-alpha, IL-6, IL-1, IL-10) immunochemically, nitric oxide (NO) by Griess-method, expression of inducible NO-synthase (iNOS) with Western Blot analysis and cytotoxicity with MTT-test. All the strains induced dose- and time-dependent production of NO, IL-6 and TNF-alpha in macrophages, whereas IL-1 or IL-10 production was not detected. The production of ROS and cytotoxicity was increased with the highest doses. Interestingly, different strains had significant differences in their ability to induce these responses, M. terrae being the most potent and M. avium-complex the weakest one. These results indicate that both non- and potentially pathogenic strains of mycobacteria present in moldy buildings are capable of activating inflammatory mechanisms in macrophages.

An enzyme-linked immunosorbent assay for the quantitative determination of anti-D in plasma samples and immunoglobulin preparations

Here we present an enzyme-linked immunosorbent assay (ELISA) on microtiter plates for the quantitative determination of anti-D. This method is based on the solubilization of red blood cells sensitized with anti-D and the subsequent measurement of immunoglobulin G by ELISA. The measuring range of the assay is 40-5,000 IU/ml and the lowest quantifiable concentration in plasma is 0.5 IU/ml. The interassay relative standard deviation for concentrations above 130 IU/ml ranges from 3.2 to 8.1% and below 50 IU/ml from 10.5 to 19.7%. Comparison of ELISA with automated hemagglutination shows that the results of the two assays correlate well: r = 0.992, n = 26. The assay was validated for donor plasma samples and anti-D immunoglobulin preparations and it can also be used in assessing the severity of Rh (D) hemolytic disease during pregnancy.

Long-term follow-up of anti-IgA antibodies in healthy IgA-deficient adults

A follow-up study of anti-IgA antibodies in 159 healthy blood donors with severe deficiency of serum IgA (< 0.05 mg/L) and in 45 donors with decreased serum IgA levels (0.05-799 mg/L), identified in 1971-1980, was carried out. Initially anti-IgA antibodies were determined by a hemagglutination (HA) method and two reexaminations were done in 1990-1992 by an enzyme immunoassay. The median follow-up period was 19 years, during which anti-IgA level was changed considerably in only four persons, increased in two, and high level antibodies (> 1/1000 by HA) appeared in two. In reexaminations anti-IgA antibodies were found in 30 (19%) subjects with severe IgA deficiency and the antibody levels remained relatively constant in those who had high and medium antibody levels. Anti-IgA antibodies were not found in subjects with decreased, but detectable serum IgA. Thus it seems that only those healthy adults who have severe IgA deficiency develop anti-IgA antibodies and their anti-IgA levels remain fairly constant. Of the 159 subjects with severe IgA deficiency, 66 had a history of IgA exposure, but no correlation to anti-IgA development was noted.

An enzyme immunoassay for the determination of anti-IgA antibodies using polyclonal human IgA

An enzyme immunoassay (EIA) for screening and quantitation of serum anti-IgA antibodies of IgG class is described. This method is based on the use of purified polyclonal human serum IgA as the coating antigen and a commercial alkaline phosphatase-conjugated anti-human IgG as the detecting antibody. Nonspecific reactions were minimized by blocking vacant protein binding sites with bovine serum albumin and by using individual sample blanks. The IgA specificity of a positive antibody finding was confirmed by testing inhibition: pooled normal human serum inhibited the binding of specific antibodies by over 80%. The same degree of inhibition could also be demonstrated by a commercial myeloma IgA preparation and by the IgA used for coating but not by IgA-deficient serum (< 0.05 mg/l). On the basis of the mean anti-IgA antibody titre in EIA, a value of 12,000 arbitrary units of anti-IgA per litre (AU/l) was assigned to a patient serum used as standard in the assay. Anti-IgA results obtained by EIA and haemagglutination correlated well, which makes it possible to compare earlier HA results with those obtained now by EIA. The measuring range of the assay was 0.6-27 AU/l and the lowest quantifiable concentration 7 AU/l. The dilution requirement for serum was 1/16. The interassay coefficients of variation for control sera with antibody levels from 35 AU/l to 3770 AU/l varied from 9 to 12%.

Long-term persistence of selective IgA deficiency in healthy adults

A follow-up study of 204 healthy blood donors with IgA deficiency, identified between 1971 and 1980, was carried out. Sera were initially screened by a double diffusion method and 182 were retested by a more sensitive haemagglutination inhibition method. A reexamination was performed in 1990 and, again, in 1991-1992 using an enzyme immunoassay (EIA) developed for the measurement of very low concentrations of IgA. The median follow-up period was 19 years, and in 159 (78%) subjects no serum IgA could be detected in any of the measurements. In 42 (21%) subjects, serum IgA was detectable (> 0.18 mg/L), but the level was below the lower limit of the reference range for adults (800 mg/L) and remained relatively constant. Three subjects showed minute amounts of IgA by EIA (0.2-3 mg/L) in one of the follow-up samples in 1990-1992, but the level was below the detection limit of the EIA (0.05 mg/L) in the other sample. Thus, not only does primary IgA deficiency appear to be permanent, but also lower than normal serum IgA levels remain the same in healthy adults.

Slipperiness of the shoe-floor interface: comparison of objective and subjective assessments

Tribollogically and biomechanically valid slip-resistance measurement methods are needed urgently to facilitate new developments for improving the safety of footwear and floor coverings. Objective coefficient-of-friction measurements and subjective walking experiments were compared to scrutinize and validate anti-slip assessments of the shoe-floor interface. Four shoe types were tested on a smooth stainless steel floor contaminated with viscous glycerol. The friction utilization ratio during one step, the sliding distance, and the subjective rating of slipperiness were evaluated by seven test subjects in 420 walking trials. All subjects assessed the footwear in the same rank of slipperiness. The friction utilization ratios during the walking trial were a poor indicator for anti-slip assessments. The apparatus-based kinetic friction values mu(k1), however, were more valid and, in particular, more reproducible. The safe level of mu(k1) was approximately 0.22, which is in accordance with previous slip-resistance clasification of shoes and floors. Futher trials in other shoe-contaminant-floor conditions and walking tasks are needed to verify the findings in this study.

A sensitive enzyme immunoassay for the measurement of low concentrations of IgA

A microtitre plate enzyme immunoassay (EIA) for determining low concentrations of IgA is described and validated for serum and plasma products. The measuring range of the assay was 3.3-150 micrograms/l. The predilution requirement of samples was matrix dependent, ranging from 1/16 for serum to 1/2 for 4% albumin. Dilute protein solutions required no predilution. The limits of detection were 50 micrograms/l for serum, 25 micrograms/l for intravenous immunoglobulin, 13 micrograms/l for 20% albumin, 7 micrograms/l for 4% albumin and 3 micrograms/l for washing solutions of blood cell components. Interassay coefficients of variation over the range of 3.4 mg to 1.5 g IgA/l ranged from 3.8 to 5.7%. Respective values for two low-level sera, containing 309 and 512 micrograms IgA/l, were 15.5% and 11.1%. Comparison of the EIA with a commercial radial immunodiffusion (RID) method showed that the results of the two assays correlated well ([EIA] = 0.877 x [RID] + 0.401 mg/l, r = 0.996, n = 20). This assay is also suitable for the large-scale screening of blood donors.