Walking with unilateral ankle-foot unloading: a comparative biomechanical analysis of three assistive devices

BACKGROUND

Foot and ankle unloading is essential in various clinical contexts, including ulcers, tendon ruptures, and fractures. Choosing the right assistive device is crucial for functionality and recovery. Yet, research on the impact of devices beyond crutches, particularly ankle-foot orthoses (AFOs) designed to unload the ankle and foot, is limited. This study investigates the effects of three types of devices-forearm crutches, knee crutch, and AFO-on biomechanical, metabolic, and subjective parameters during walking with unilateral ankle-foot unloading.

METHODS

Twenty healthy participants walked at a self-selected speed in four conditions: unassisted able-bodied gait, and using three unloading devices, namely forearm crutches, iWalk knee crutch, and ZeroG AFO. Comprehensive measurements, including motion capture, force plates, and metabolic system, were used to assess various spatiotemporal, kinematic, kinetic, and metabolic parameters. Additionally, participants provided subjective feedback through questionnaires. The conditions were compared using a within-subject crossover study design with repeated measures ANOVA.

RESULTS

Significant differences were found between the three devices and able-bodied gait. Among the devices, ZeroG exhibited significantly faster walking speed and lower metabolic cost. For the weight-bearing leg, ZeroG exhibited the shortest stance phase, lowest braking forces, and hip and knee angles most similar to normal gait. However, ankle plantarflexion after push-off using ZeroG was most different from normal gait. IWalk and crutches caused significantly larger center-of-mass mediolateral and vertical fluctuations, respectively. Participants rated the ZeroG as the most stable, but more participants complained it caused excessive pressure and pain. Crutches were rated with the highest perceived exertion and lowest comfort, whereas no significant differences between ZeroG and iWalk were found for these parameters.

CONCLUSIONS

Significant differences among the devices were identified across all measurements, aligning with previous studies for crutches and iWalk. ZeroG demonstrated favorable performance in most aspects, highlighting the potential of AFOs in enhancing gait rehabilitation when unloading is necessary. However, poor comfort and atypical sound-side ankle kinematics were evident with ZeroG. These findings can assist clinicians in making educated decisions about prescribing ankle-foot unloading devices and guide the design of improved devices that overcome the limitations of existing solutions.

Clinical impact of allergy and pre-medication in CT studies with low-osmolality intravenous iodinated contrast media

AIM

To evaluate the occurrence and severity of allergic reactions to iodinated contrast media (ICM), including associated risk factors and the impact of pre-medication.

MATERIALS AND METHODS

Data on patients who had experienced allergic reactions during outpatient computed tomography (CT) examinations between January 2014 and September 2018 were analysed retrospectively. Response severity was assessed according to validated criteria. A control group was selected among individuals who underwent CT during the study period and did not experience allergic reactions.

RESULTS

Screening of 36,920 CT studies revealed 74 (0.2%) individuals with systemic reactions to ICM. No significant differences in patient characteristics were found among patients who experienced mild (n=54), moderate (n=17), or severe (n=4) reactions. Previous ICM allergy was reported in 10 patients (13.3%). Patients with a history of ICM allergy had mild (9/10) or moderate (1/10) reactions, with one individual showing decreased intensity of the allergic response compared to a previous event. Within the control group, four patients (4%) had previous ICM allergy. In these individuals, lack of allergic reactions could not be attributed to pre-medication. All patients with severe reactions did not have a prior history of ICM allergy.

CONCLUSION

Severe allergic reactions to ICM are rare, lack significant risk factors, and do not appear to be impacted by pre-medication. The findings presented herein highlight the need for prospective work that will re-evaluate the yield of pre-medication protocols.

γδT Cells Are Essential for Orthodontic Tooth Movement

Sustained mechanical forces applied to tissue are known to shape local immunity. In the oral mucosa, mechanical stress, either naturally induced by masticatory forces or externally via mechanical loading during orthodontic tooth movement (OTM), is translated, in part, by T cells to alveolar bone resorption. Nevertheless, despite being considered critical for OTM, depletion of CD4⁺ and CD8⁺ T cells is reported to have no impact on tooth movement, thus questioning the function of αβT cells in OTM-associated bone resorption. To further address the role of T cells in OTM, we first characterized the leukocytes residing in the periodontal ligament (PDL), the tissue of interest during OTM, and compared it to the neighboring gingiva. Unlike the gingiva, monocytes and neutrophils represent the major leukocytes of the PDL. These myeloid cells were also the main leukocytes in the PDL of germ-free mice, although at lower levels than SPF mice. T lymphocytes were more enriched in the gingiva than the PDL, yet in both tissues, the relative fraction of the γδT cells was higher than the αβ T cells. We thus sought to examine the role of γδT cells in OTM. γδT cells residing in the PDL were mainly Vγ6⁺ and produced interleukin (IL)-17A but not interferon-γ. Using Tcrd-GDL mice allowing conditional ablation of γδT cells in vivo, we demonstrate that OTM was greatly diminished in the absence of γδT cells. Further analysis revealed that ablation of γδT cells decreased early IL-17A expression, monocyte and neutrophil recruitment, and the expression of the osteoclastogenic molecule receptor activator of nuclear factor-κβ ligand. This, eventually, resulted in reduced numbers of osteoclasts in the pressure site during OTM. Collectively, our data suggest that γδT cells are essential in OTM for translating orthodontic mechanical forces to bone resorption, required for relocating the tooth in the alveolar bone.

Exogenous interleukin-2 can rescue in-vitro T cell activation and proliferation in patients with a novel capping protein regulator and myosin 1 linker 2 mutation

Capping protein regulator and myosin 1 linker 2 (CARMIL2) deficiency is characterized by impaired T cell activation, which is attributed to defective CD28-mediated co-signaling. Herein, we aimed to analyze the effect of exogenous interleukin (IL)-2 on in-vitro T cell activation and proliferation in a family with CARMIL2 deficiency. This study included four children (one male and three females; aged 2·5-10 years at presentation). The patients presented with inflammatory bowel disease and recurrent viral infections. Genetic analysis revealed a novel homozygous 25-base pairs deletion in CARMIL2. Immunoblotting demonstrated the absence of CARMIL2 protein in all four patients and confirmed the diagnosis of CARMIL2 deficiency. T cells were activated in-vitro with the addition of IL-2 in different concentrations. CD25 and interferon (IFN)-γ levels were measured after 48 h and 5 days of activation. CD25 surface expression on activated CD8⁺ and CD4⁺ T cells was significantly diminished in all patients compared to healthy controls. Additionally, CD8⁺ T cells from all patients demonstrated significantly reduced IFN-γ production. When cells derived from CARMIL2-deficient patients were treated with IL-2, CD25 and IFN-γ production increased in a dose-dependent manner. T cell proliferation, as measured by Cell Trace Violet, was impaired in one patient and it was also rescued with IL-2. In conclusion, we found that IL-2 rescued T cell activation and proliferation in CARMIL2-deficient patients. Thus, IL-2 should be further studied as a potential therapeutic modality for these patients.

Alopecia areata in patients with systemic lupus erythematosus treated with belimumab: a plausible association

Belimumab, an anti-B-lymphocyte stimulator monoclonal antibody, was recently approved for the treatment of systemic lupus erythematosus. Alopecia areata is characterized by an acute immune-mediated hair loss. Herein, we report on three adult systemic lupus erythematosus patients who developed alopecia areata in association with belimumab treatment. Alopecia areata was resolved in all three patients and belimumab was discontinued in two of them. Thus, in the current report, we explore the plausible link between alopecia areata and belimumab.

Transgenic over-expression of mammalian heparanase delays prion disease onset and progression

Cellular heparan sulfate (HS) has a dual role in scrapie pathogenesis; it is required for PrP(Sc) (scrapie prion protein) formation and facilitates infection of cells, mediating cellular uptake of prions. We examined the involvement of heparanase, a mammalian endoglycosidase degrading HS, in scrapie infection. In cultured cells, heparanase treatment or over-expression resulted in a profound decrease in PrP(Sc). Moreover, disease onset and progression were dramatically delayed in scrapie infected transgenic mice over-expressing heparanase. Together, our results provide direct in vivo evidence for the involvement of intact HS in the pathogenesis of prion disease and the protective role of heparanase both in terms of susceptibility to infection and disease progression.

Influence of Volatile Fatty Acids on Nitrite Accumulation by a Pseudomonas stutzeri Strain Isolated from a Denitrifying Fluidized Bed Reactor

Intermediate nitrite accumulation during denitrification by Pseudomonas stutzeri isolated from a denitrifying fluidized bed reactor was examined in the presence of different volatile fatty acids. Nitrite accumulated when acetate or propionate served as the carbon and electron source but did not accumulate in the presence of butyrate, valerate, or caproate. Nitrite accumulation in the presence of acetate was caused by differences in the rates of nitrate and nitrite reduction and, in addition, by competition between nitrate and nitrite reduction pathways for electrons. Incubation of the cells with butyrate resulted in a slower nitrate reduction rate and a faster nitrite reduction rate than incubation with acetate. Whereas nitrate inhibited the nitrite reduction rate in the presence of acetate, no such inhibition was found in butyrate-supplemented cells. Cytochromes b and c were found to mediate electron transport during nitrate reduction by the cells. Cytochrome c was reduced via a different pathway when nitrite-reducing cells were incubated with acetate than when they were incubated with butyrate. Furthermore, addition of antimycin A to nitrite-reducing cells resulted in partial inhibition of electron transport to cytochrome c in acetate-supplemented cells but not in butyrate-supplemented cells. On the basis of these findings, we propose that differences in intermediate nitrite accumulation are caused by differences in electron flow to nitrate and nitrite reductases during oxidation of either acetate or butyrate.

Nitrate removal in aquariums by immobilized pseudomonas

Biological denitrification of nitrate to nitrogen gas was examined in a freshwater and a marine aquarium. Nitrate removal in the aquarium water was accomplished with denitrifiers immobilized in a freeze-dried, alginate-starch matrix. Starch served as a bacterial carbon source and cellular matrix-strengthening filler. Freeze-dried beads were placed in canisters through which nitrate-rich aquarium water was recirculated. The freshwater aquarium (100 L) contained goldfish (Carassius auratus) at a total biomass of 390 g, whereas cichlids (Oreochromis mossambicus) were kept at a similar stocking density in the marine aquarium. Denitrification resulted in low ambient nitrate concentrations in both aquariums. The specific nitrate removal rate of the freshwater beads was significantly higher (50 microg of NO(3)-N/bead/day) than that of seawater beads (5 microg of NO(3)-N/bead/day). Differences in ambient nitrate concentrations between both aquariums and diffusion limitation of nitrate to the active denitrification sites within the beads might explain these observed differences.

Modulation of proteinase-K resistant prion protein by prion peptide immunization

Prion diseases are caused by conformational alterations in the prion protein (PrP). The immune system has been assumed to be non-responsive to the self-prion protein, therefore, PrP autoimmunity has not been investigated. Here, we immunized various strains of mice with PrP peptides, some selected to fit the MHC class II-peptide binding motif. We found that specific PrP peptides elicited strong immune responses in NOD, C57BL/6 and A/J mice. To test the functional effect of this immunization, we examined the expression of proteinase-K-resistant PrP by a scrapie-infected tumor transplanted to immunized syngeneic A/J mice. PrP peptide vaccination did not affect the growth of the infected tumor transplant, but significantly reduced the level of protease-resistant PrP. Our results demonstrate that self-PrP peptides are immunogenic in mice and suggest that this immune response might affect PrP-scrapie levels in certain conditions.

Enumeration and factors influencing the relative abundance of a denitrifier, Pseudomonas sp. JR12, entrapped in alginate beads

The relative abundance of the denitrifier, Pseudomonas sp. JR12, was examined in an alginate-based entrapment complex under non-sterile, denitrifying conditions. Immuno-labeling of the Pseudomonas inoculant followed by flow cytometry (FCM) was used for determination of the relative abundance of this bacterium under the various incubation conditions. Additional information on the relative abundance of the inoculant was obtained by a quantitative enzyme-linked immunosorbent assay (ELISA) and results obtained by FCM and ELISA were compared. Ambient nitrate levels controlled the successful, long-term proliferation of the inoculant. At low ambient nitrate levels, Pseudomonas sp. remained the dominant microorganism during incubation. Higher ambient nitrate concentrations, attained by either decreasing the inoculum size of Pseudomonas sp. or raising inlet nitrate concentrations of the medium supplied to the incubation vessels, resulted in a gradual shift toward other, nitrite-accumulating denitrifiers. Thus far, most studies on the use of entrapped microorganisms for bioremediation purposes have been conducted under controlled laboratory conditions. Based on this study, conducted under non-sterile laboratory conditions, it is concluded that in-situ bioremediation using entrapped target microorganisms is bound to fail without a proper understanding of the factors that cause the target microorganism to out-compete undesired microbial invaders. Furthermore, based on the close agreement between the two detection methods used, it is concluded that flow cytometry provides a rapid and accurate tool for the detection of the relative abundance of immuno-labeled target organisms in heterogeneous microbial populations.

Infants with a thumb-in-fist posture

OBJECTIVE

In early infancy the infant's thumb is not infrequently enclosed within the palm, ie, thumb-in-fist (TIF). This posture has received scant attention in the neurodevelopmental literature. Its prevalence, resolution, and clinical associations were investigated in this study.

METHODOLOGY

Two hundred sequentially born, apparently healthy full-term newborn infants comprised the cohort. The whole study group was followed up until the disappearance of the TIF occurred. In the first 150 of the cohort, additional data on development and the neurological status were obtained at 12 months of life.

RESULTS

In 125 infants (62.5%) of the total cohort, a TIF was noted. The mean age of disappearance was 1.5 months, and no TIF persisted after 7 months old. No relationship was noted between the TIF resolution and abnormal neurological signs or gross or fine motor development. The only association noted between age of resolution of the TIF and the neurodevelopmental status was a delay in language attainment at the 12-month screening.

CONCLUSIONS

The TIF posture in infancy was noted in 65% of our cohort, and it had resolved in all infants by 7 months old. Therefore, a TIF posture after this age should alert the clinician to the possibility of possible neurological dysfunction. An unanticipated association of a delay in the 12-month language milestone attainment was noted in those infants with later resolution of the TIF posture. No data on language development in this group were obtained after 12 months old; therefore, the clinical significance of this finding is not yet elucidated.

Fetal cardiac measurements derived by transvaginal and transabdominal cross-sectional echocardiography from 14 weeks of gestation to term

OBJECTIVE

Most of the routine ultrasound screening in our institution consists of early transvaginal examinations at 14-17 weeks. Complete fetal echocardiography is performed in every case. However, normal values for most fetal cardiac structures at this stage of gestation are not available. Our aim was to construct normal ranges for fetal cardiac structures, derived from cross-sectional echocardiography, at 14-40 weeks of gestation.

DESIGN

A prospective study was performed. The study group consisted of 637 pregnant women referred for a routine sonographic examination. Women with abnormal prenatal or postnatal outcome were not included in the study. Transvaginal examinations were used for 14-17 weeks of gestation. More advanced pregnancies were examined transabdominally.

RESULTS

We constructed normal ranges for the left and right end-diastolic transverse ventricular diameters (n = 637), left/right ventricular ratio (n = 637), aortic root diameter (n = 637), pulmonary artery diameter (n = 637), aortic/pulmonary ratio (n = 490), left and right transverse atrial diameters (n = 201) and left/right atrial ratio (n = 201).

CONCLUSIONS

The results provide the examiner with normal ranges for fetal cardiac structures for the early transvaginal examination. The continuity of all curves from 14 to 40 weeks of gestation allows follow-up of any specific fetus to term.

[Nasopharyngeal colonization with Streptococcus pneumoniae in pediatric respiratory infections]

During the winter of 1995, nasopharyngeal colonization of Streptococcus pneumoniae was evaluated in 204 children with respiratory infection and 107 normal control children. There was no difference in gender or mean age between the groups, and no difference in carrier rate between sick (24.5%) and normal (22%) children (p = 0.6). Carrier rates were 19%, 32%, 31% and 17% at 6, 12, 24 and 48 months, respectively. Penicillin-resistant pneumococci (PRP) were found in 42% of sick and 16.6% of normal children, (p < 0.05). Resistance to more than 2 antibiotics was found in 28% of sick and in 12.5% of normal children. PRP were found in 67% and 34% of sick children with and without prior antibiotic treatment (p < 0.05). We conclude that there is no difference in the carrier rate of Streptococcus pneumoniae between sick and normal children. However, the high prevalence of PRP in children with respiratory infections is probably due to prior antibiotic treatment.

Platelet activation in patients with antiphospholipid syndrome

The binding of antiphospholipid antibodies to circulating platelets and the potential association with thrombocytopenia and platelet activation was investigated in 25 patients with primary antiphospholipid syndrome (APS). Fourteen patients had a platelet count above 150 x 10(9)/l, and 11 patients had mild to moderate thrombocytopenia of 50-150 x 10(9)/l. The presence of platelet autoantibodies was investigated by immunofluorescent binding. No correlation between the presence of autoantibodies on platelets and thrombocytopenia was found. The binding of antibodies in patients' serum and platelet eluates was investigated by performing enzyme-linked immunosorbent assays with phospholipids as antigens. In seven patients antibodies to negatively charged phospholipids were present in platelet eluates. Platelet activation was measured by flow cytometry using a fluorescein isothiocyanate (FITC) labeled monoclonal antibody to P-selectin (CD62). The binding of anti-P-selectin to patients' platelet surface P-selectin was not increased, compared with the binding to platelets obtained from normal donors. Platelet serotonin concentration in APS patients was significantly lower than that found in the platelets of normal controls. More studies are necessary to determine the exact role of antiphospholipid antibodies in the pathogenesis of thrombocytopenia, and to elucidate the cause of low serotonin levels in platelets of APS patients.

Apnoea-associated heart rate changes among preterm and full-term infants exposed to hyperthermia

Heart rate (HR) changes associated with apnoea (> 3 s) were analysed in 10 preterm infants (30.6 +/- 1.5 weeks) at post-conceptional age of 40 +/- 1.5 weeks and 10 full-term (FT) infants (39 +/- 1 weeks) before, during and after exposure to increased environmental temperature (5 degrees C above normothermia). A significantly increased HR was found in the study group during the baseline (normothermia), heating, cooling and final normothermic phase compared with the control infants. No significant difference was found between the groups during the hyperthermic stage. A significant relative increase in HR was found among the preterm infants but not among FT infants during central apnoea at the hyperthermia phase. Our results indicate that HR control during apnoea in preterm infants is more labile then among FT infants while being exposed to increased environmental temperature.

Light-Mediated Nitrite Accumulation during Denitrification by Pseudomonas sp. Strain JR12

The effect of light on the denitrifying characteristics of a nonphotosynthetic denitrifier, Pseudomonas sp. strain JR12, was examined. Already at low light intensities, nitrite accumulated as a result of light inhibition of nitrite but not of nitrate reduction rates. Exposure of this bacterium to light caused a photooxidation of cytochrome c , an intermediate electron carrier in its respiratory pathway. Photoinhibition of nitrite reduction was reversible, as nitrite reduction rates returned to preillumination levels when light-exposed cells were returned to dark conditions. Antimycin A reversed the inhibitory effect of light on nitrite reduction by preventing a reversed electron flow. Aerobic respiration by this bacterium was not affected by light.

The clinical significance of rigors in febrile children

The objective of the study was to evaluate the significance of rigor as a predictor of bacterial infection in hospitalized febrile infants and children. One hundred febrile children with rigor were studied and compared to 334 febrile matched controls without rigor. All underwent clinical evaluation and appropriate laboratory investigations. The patients were then divided into "bacterial" and "non bacterial" infection groups, as defined in the text. It was demonstrated that 66% of the patients with rigor belonged to the bacterial infection group versus 50% in the non-rigor group (P < 0.005). There was a significantly greater yield of positive blood cultures in the patients with rigor (P < 0.04), especially those over the age of 1 year (P < 0.015). The only laboratory examination of potential value as a predictor of bacterial infection in children with rigor was the band count. An absolute band count of more than 1500/mm was significantly more frequent in the rigor group (P < 0.003), and the combination of a rigor and band count of more than 1500 increased the relative risk for a bacterial infection by a factor of 1.35. These data demonstrate that rigor in hospitalized febrile infants or children significantly increase the likelihood of bacterial infection.

CONCLUSION

Although the absence of rigors in febrile children does not exclude bacterial aetiology, their presence significantly increase the probability of an infection requiring appropriate workup and a reader institution of antibiotic therapy.

Reversible brain atrophy and reversible developmental retardation in a malnourished infant

An 11-month-old infant suffering from microcephalus, developmental delay, severe failure to thrive and marked cortical atrophy on brain CT is presented. The cause of this condition was total calorie malnutrition induced by the emotional dysfunction of the mother. Improvement of the maternal-infant relationship, combined with appropriate nutrition, transformed the infant within 2 months into a normally developing baby with body weight and head circumference within the normal percentile range. A corresponding improvement was found in the brain CT.

The parachute reactions in normal and late walkers

To study the relationship of the parachute responses to the age of independent walking, three groups of infants were prospectively examined: a normal sitting, normal walking group; a late sitting, normal walking group; and a late sitting, late walking group. All other spheres of the neurodevelopmental examination were normal. It was found that when the parachute responses appeared by age 10 months in the late sitting infants, most of them would achieve independent walking by 15 months. A delay in the parachute reaction in these infants predicted a delay in walking.

Transverse bond strength of repaired acrylic resin strips and temperature rise of dentures relined with VLC reline resin

This study measured the transverse strength of polymethyl methacrylate heat-cured resin samples repaired with Triad visible light-cured reline resin with and without bonding pretreatments and with autopolymerizing resin, and it measured the temperature rise of Triad resin during relining of complete dentures at various curing cycles. The results indicated that pretreatment with either monomer or Triad bonding agent improved the bond of the Triad visible light-cured reline resin to the heat-cured resin. However, the use of the monomer rather than bonding agent resulted in a stronger bond and obtained values similar to those of samples repaired with autopolymerizing resin. Polymerization of samples repaired with Triad resin in the curing unit for two cycles of 5 minutes with 1 minute between cycles resulted in bubble formation and severe distortion of the heat-cured resin in the samples. Curing of the relined dentures for 10 minutes as recommended by the manufacturer raised the average peak temperature to 120 degrees C. In addition, it was shown that interrupting the light curing cycle attenuated the temperature rise, but it also resulted in a relatively softer reline resin. A continuous light curing of at least 5 minutes with the adjunct temperature rise is required to reach 1-hour hardness of 21.8 Vickers hardness number of the Triad reline resin.

CPAP treatment of obstructive sleep apnoea and neurodevelopmental deficits

Four boys aged 6-16 years with neurodevelopmental deficits were treated with CPAP for obstructive sleep apnoea. Their diagnoses were: Obesity with mild mental retardation, (2) attention deficit hyperactivity disorder, (3) epilepsy associated with left hemiparesis and (4) mild mental retardation due to fragile X syndrome. Previous therapeutic attempts, including adenotonsillectomy, amitriptyline and methylphenidate in our patients prior to CPAP treatment were unsuccessful. A follow-up period of 12-48 months demonstrated a number of clinical benefits such as improvement in sleep quality and daily arousal, and a decrease in the frequency of seizures and episodes of pneumonia. Polysomnographic studies indicated a significant improvement in sleep parameters such as apnoea frequency, awakenings, sleep efficiency and arterial oxygen saturation. Side effects were mild and readily alleviated. CPAP is a feasible therapeutic intervention in intractable obstructive sleep apnoea of childhood, even when associated with neurodevelopmental deficits.

Congenital toxoplasmosis: a significant cause of neurological morbidity in Israel?

The incidence of congenital toxoplasmosis in Israel is largely unknown, as is the impact of this condition on the neurological diseases of childhood. We examined the association between toxoplasmosis and three neurological disorders: epilepsy, cerebral palsy, and nerve deafness. Ninety-five children 1-15 years of age who had one of these three diagnoses but who had not had perinatal meningitis or anoxia and had no genetic predisposition for the documented neurological disorder were eligible for the study; 109 children hospitalized for elective surgery served as age-matched controls. Demographic and serological data were analyzed by logistic regression. The prevalences of serum antibodies to Toxoplasma gondii in the study and control groups were 22% and 9%, respectively. Children with one of the three neurological disorders were significantly more likely to have IgG antibodies to T. gondii (relative risk, 2.5; P = .03). The relative risk of seropositivity was remarkably high (7.1) among children with nerve deafness (P = .01). Large-scale prospective cohort studies of pregnant women are needed to substantiate the impact of congenital toxoplasmosis on the neurological diseases of childhood in Israel.

Relationship of sweat electrolytes to apparent life-threatening events (ALTE): a case control study

Twenty infants aged 25 days to 6 months who were consecutively investigated for apparent life-threatening events (ALTE) with negative results and 20 matched normal controls underwent an iontophoresis sweat test. A statistically significant elevated sweat potassium level (22.1 +/- 8.9 versus 12.4 +/- 6.5 mol/l) was noted in the ALTE patients compared with the control group (p < 0.001). No difference was found, however, between sweat sodium and chloride levels in the two groups. Na/K ratio in sweat was significantly different between the groups (p < 0.001). A between-groups discriminant analysis, using Na/K ratio as a discriminant variable, resulted in 80% accuracy in group assignment. A significant increase in sweat potassium concentration at night compared with day time was evident in ALTE patients. Elevated sweat potassium levels specifically characterized infants who experienced ALTE and may possibly indicate an underlying mechanism involving enhanced sympathetic activity.

The relationship between joint hypermobility and neurodevelopmental attributes in elementary school children

Joint hypermobility is associated with motor developmental delay in infancy. To assess this finding in school-aged children, 320 first- and second-grade elementary school children and 110 children attending a special education program were assessed. Joint hypermobility was found in 40 (12.4%) and seven (6.4%) of the children attending the regular and special education classes, respectively. No difference in the neurologic status or verbal and eye-hand coordination task performance was found between the children of the study group and their age- and sex-matched controls. It appears that joint hypermobility and neurodevelopmental dysfunctions are not causally related and have a different maturational course.

Relationship between the parachute reactions and standing and walking in normal infants

Assumption of the vertical position and independent walking are potentially hazardous motor milestones in the developing infant. It has been presumed that the parachute reactions evolved to protect infants from injury during this developmental stage. To determine the relationship between the appearance of the upper and lower parachute reactions and the developmental milestones of unsupported standing and independent walking, 190 normal infants were prospectively studied. The upper parachute reaction was found to precede the lower by less than a month (mean age of appearance: 8.9 and 9.2 months, respectively). More than one-half of the cohort achieved standing without either the upper (49%) or lower parachute reaction (57%); however, no independent walking occurred without the upper parachute reaction, and only 2 of 190 infants (1%) walked independently without the lower parachute reaction. Onset of walking occurred about 4 months after the appearance of the upper parachute reaction. The significance of these findings is discussed.

Kohlschütter-Tönz syndrome: epilepsy, dementia, and amelogenesis imperfecta

Kohlschütter-Tönz syndrome is a central nervous system (CNS) degenerative disease with convulsions and mental regression in which the affected children present with yellow teeth due to defective enamel. We present a family in which 2 affected children (a boy and a girl) were born to consanguineous parents. This report confirms the autosomal recessive inheritance of the disorder. The combination of a CNS and an enamel defect may represent pleiotropy or a contiguous gene syndrome.

Variability in head circumference growth rate during the first 2 years of life

The head circumference (HC) curves were plotted for a group of 415 healthy full-term babies over the first 2 years of life. Two hundred ten (51%) of the cohort demonstrated HC variability, defined as an HC acceleration or deceleration of at least 1 centile curve for at least 2 months. Of these, the deceleration pattern was predominant (80.9%), and also frequently permanent (87%). The HCs of 3 (1.42%) of 210 infants with HC variability ended up with a deviation of 2 standard deviations or more from the mean. The onset of HC transition occurred from the mean age of 1.3 months, and the new curve had stabilized by age 13 months in 95% of the study group. Parallel changes occurred in body weight and body length in approximately 48% of the total cohort, but more frequently in the variable-HC group. The clinical interpretation of these findings is discussed.

Effect of beta-endorphin on human chorionic gonadotrophin secretion by placental explants

In the present study the effect of physiological concentrations of beta-endorphin was examined upon human chorionic gonadotrophin (HCG) secretion by first trimester placental explants. Results show that at 7-9 weeks of gestation, beta-endorphin inhibited HCG secretion; a maximal suppression of 60% was noted at 5 x 10(-10) M concentrations, while fivefold lower or higher doses were less effective. This inhibitory effect was completely reversed by naloxone, an opiate receptor antagonist, indicating involvement of an opiate receptor in the action of beta-endorphin. The opioid peptide specificity was demonstrated by the failure of N-acetyl-beta-endorphin, a non-opiate analogue used at the same concentration range, to affect HCG secretion. Following the HCG peak, at 11 weeks however, the effect of beta-endorphin was stimulatory on HCG secretion, which suggests a gestational age-dependent effect of the opioid peptide. In conclusion, these data indicate that beta-endorphin, a mu and delta opioid receptor ligand, has a modulatory effect on HCG secretion in vitro in the young placenta.

High dose intravenous gamma-globulin in intractable epilepsy of childhood

Eight children aged between 1.3 and 13 years suffering from epilepsy refractory to conventional anticonvulsive therapy were treated with high dose intravenous gamma globulin (200 mg/kg, 3 times per week, repeated after 3 weeks). Immunological studies after therapy showed normal results. In four children, clinical and EEG findings markedly improved. In one other case a partial response was noted. No improvement was observed in the remaining three cases. We confirm that although the mechanism is still obscure, high doses of i.v. gammaglobulin may have a beneficial effect in a significant number of children with intractable epilepsy.

A new method for fetal ECG detection

Presented in this work is the theoretical basis of a new method we propose for the analysis of fetal ECG (FECG). This method is intended to detect the fetal HR from a weak FECG signal, and to supply us with an average FECG complex. The FECG signals studied in this work were recorded from the maternal abdominal wall. The core of our method is the computation of a triple parametric transform, using analyzing functions which have a greater correlation with the ECG signal than the correlation of the standard sine and cosine functions used in a Fourier transform. The functions used are trains of square waves characterized by the width of the square wave, their periodicity, and some initial phase value. This method, applied here to a medical problem, can be more generally applied to handle weak quasiperiodic sharp signals of any origin.

The ameliorating effect of lumbar puncture in viral meningitis

To test the hypothesis that lumbar puncture in viral meningitis results in symptomatic improvement, a group of 48 children was studied. Twenty-six patients had proved aseptic meningitis, and 22 had infections outside the central nervous system. Before and after lumbar puncture each subject was repeatedly scored for symptoms independently by the attending pediatrician and a parent. Marked symptomatic improvement in children with meningitis was demonstrated following lumbar puncture, while no significant change was demonstrated in the control group. The mechanism underlying this improvement is not clear; however, we consider a number of possible explanations.

Subacute meningitis caused by Brucella: a diagnostic challenge

A case of subacute meningitis caused by Brucella mellitensis is described. The meningitis was refractory to an antibiotic regime. Diagnosis was established by raised antibody titres to Brucella in serum and cerebrospinal fluid (CSF) and positive bone marrow and blood cultures. While treatment with tetracycline trimethoprim-sulfamethoxazole and streptomycin resulted in a dramatic clinical cure, the CSF findings returned only gradually to normal values over the ensuing 6 months.

Gaucher disease: assessment with MR imaging

The skeletal system, spleen, and liver of five patients with proved Gaucher disease were studied with magnetic resonance (MR) imaging. Homogeneous, low intensity signals resulting from relaxation times different than normal (longer T1 and shorter T2 values) were found in the marrow of long bones, vertebrae, and hips in all patients. In three patients, normal signals were noted in the patella, epiphysis of the knee, and capital femoral epiphysis. In two patients with acute bone pain in the tibial region, a higher signal was received from the tibial marrow. This signal was related to increased accumulation of fluid following an avascular episode. Soft tissues in the same area were also involved. Liver and spleen enlargement was readily visible, especially on coronal images. T1 values of spleen were significantly shorter than normal. MR imaging provides an excellent assessment of the extent of involvement of the liver, spleen, and bone marrow in Gaucher disease.

Growth failure due to protein loss in dermatitis

A 10-month-old infant is described who suffered from extensive atopic dermatitis, failure to thrive, hypoalbuminaemia and oedema. Large amounts of sticky exudate were lost through the skin and were shown to be rich in albumin. As renal and intestinal loss of protein was excluded, the patient's condition was ascribed to the loss of albumin through the skin at a rate that out-stripped the synthesis of this protein. Treatment with steroids resulted in dramatic clearing of his dermatitis, and subsequent rapid correction of his hypoalbuminaemia, oedema and anaemia.

Childhood migraine--a dangerous diagnosis?

The diagnosis of childhood migraine cannot be confirmed in any objective way. The danger of missing brain tumours or cerebral vascular malformations in these patients was examined in two groups. 73 children who were diagnosed as childhood migraine were followed for 5.4 years. No brain tumour or vascular malformation was found, but two children diagnosed as "abdominal migraine" had a different important disease. The charts of 83 children with brain tumours and seven children with vascular malformations were examined. Only three children could be confused with migraine, and only one actually was.