The development of the subplate and thalamocortical connections in the human foetal brain

The aim of this review is to present clinically relevant data on prenatal development of thalamocortical connections in the human brain. The analysis is based on extensive Zagreb Neuroembryological Collection, including more than 500 prenatal human brains stained with various classical neurohistological, as well as modern histochemical and immunohistochemical methods. The connection of thalamocortical axons during the ‘waiting’ period with transient cortical subplate zone and subsequent synaptic engagement in the cortical plate is the main connectivity event in the late foetus and preterm infant. This connectivity is the structural substrate for the endogeneous subplate and sensory‐driven circuitry generating transient electrical phenomena and may represent a transient network in the developmental history of consciousness. Conclusion: Findings presented in this review should be considered in the management of pain in preterm infants, in searching for the vulnerability of the subplate zone in diagnostic procedures using the in vivo MRI and in revealing the developmental origin of cognitive and mental disorders.     

Efficacy and safety of diphenylcyclopropenone among Chinese patients with steroid resistant and extensive alopecia areata

Background Topical immunotherapy has recently been found useful in the treatment of chronic and extensive Alopecia Areata (AA). Objective To evaluate the efficacy and safety of diphenylcyclopropenone (DPCP) use among Chinese patients with steroid resistant and extensive AA in our institute. Methods The medical records of 31 Chinese patients treated with DPCP were analysed retrospectively. The efficacy, adverse effects, and relapse rate of DPCP treatment were reviewed. Results Thirty‐one (16 male, 15 female) Chinese patients with extensive, steroid resistant Alopecia Areata and a mean age of 28.9 years (SE 10.4) were treated. The mean age of onset was 17.8 years (SE 8.8) with an average disease duration of 11.2 years (SE 7.7). Ten patients had a history of atopy and 4 had a history of thyroid disease. Nail changes were found in 14 patients and a family history of AA was found in 2 patients. Thirteen patients (41.9%) had experienced total hair loss. Two patients abandoned the treatment due to severe side effects. Of the remaining 29 patients, 4 (13.8%), 7 (24.1%), 5 (17.2%), and 13 (44.8%) achieved >90% complete response, >50–90% partial response, >10–50% minimal response, and <10% no response hair regrowth, respectively. Adverse effects included pruritus, erythema, vesiculation, scaling, cervical lymphadenopathy, dyspigmentation and urticarial reactions. Relapse occurred (>25% hair loss) in 69.23% of patients after 18 months of follow up. Conclusions DPCP is an effective and tolerable treatment for Chinese patients with extensive, steroid resistant AA.     

Effects of process and formulation parameters on characteristics and internal morphology of poly(d,l-lactide-co-glycolide) microspheres formed by the solvent evaporation method.

Taking ABT627 as a hydrophobic model drug, poly-(lactic-co-glycolic acid) (PLGA) microspheres were prepared by an emulsion solvent evaporation method. Various process parameters, such as continuous phase/dispersed phase (CP/DP) ratio, polymer concentration, initial drug loading, polyvinyl alcohol concentration and pH, on the characteristics of microspheres and in vitro drug release pattern of ABT627 were investigated. Internal morphology of the microspheres was observed with scanning electron microscopy by stereological method. CP/DP is a critical factor in preparing microspheres and drug loading increased significantly with increasing CP/DP ratios accompanied by a remarkably decreased burst release. At CP/DP ratio 20, microspheres with a core-shell structure were formed and the internal porosity of the microspheres decreased with increasing CP/DP ratio. Increase in PLGA concentration led to increased particle sizes and decreased drug release rates. ABT627 release rate increased considerably with increasing PVA concentrations in the continuous phase from 0.1% to 0.5%. The maximum solubility of ABT627 in PLGA was approximately 30%, under which ABT627 was dispersed in PLGA matrix in a molecular state. Increase in initial drug loading had no significant influence on particle size, drug encapsulation efficiency, burst release and internal morphology. However, drug release rate decreased at higher drug loading. Independent of process parameters, ABT627 was slowly released from the PLGA microspheres over 30 days, by a combination of diffusion and polymer degradation. During the first 13 days, ABT627 was mainly released by the mechanism of diffusion demonstrated by the unchanged internal morphology. In contrast, a core-shell structure of the microspheres was observed after being incubated in the release medium for 17 days, independent of drug loading, implying that the ABT627/PLGA microspheres degraded by autocatalytic effect, starting from inside of the matrix. In conclusion, hydrophobic drug release from the PLGA microspheres is mainly dependent on the internal morphology and drug distribution state in the microspheres.     

Cochlear implant in Hong Kong Cantonese

Cochlear implant surgery was performed in four Cantonese-speaking postlingually deaf Chinese adults, using the House/3M single channel device. This article outlines the methodology, including preoperative assessment and postoperative rehabilitation; and explains the necessary modifications in speech and audiologic work-up in Cantonese-speaking patients. Salient features of Cantonese phonetics, especially its tonal characteristics, are described. The findings of the study are presented. The results of the cochlear implant would suggest a performance superior to that of the hearing aid. Furthermore, the cochlear implant is able to detect tonal cues. This quality of the cochlear implant may prove to be a valuable asset to a tonal language-speaking cochlear implantee.     

Cone differentiation with no photopigment coexpression

PURPOSE: To decide whether the transitory coexpression of cone visual pigments described in the developing rat and gerbil retina is a universal feature of dichromatic mammalian species. METHODS: The rabbit, a species widely used in eye research, was selected for the study and a search made for the presence of cones that bound more than one cone antibody during the first postnatal week. To plot the densities of individual cone types and to colocalize the two visual pigments, immunocytochemistry on retinal wholemounts and consecutive tangential sections, respectively, were used. RESULTS: The sequence in which the visual pigments began to be expressed was the same as that observed in other mammals: first, rhodopsin; second, blue pigment; and last, green pigment. The striking increase in blue cone density numbers observed in the rat, however, did not occur in the rabbit. Instead, some days after the first blue cones appeared, the green cones also started to express their visual pigment, and this cone type soon outnumbered the blue cones. Within the limits of the immunocytochemical method, it was established that unlike the developing rat, the presence of double-labeled cones was not a character of the rabbit retina. CONCLUSIONS: Visual pigment coexpression is an interesting phenomenon of retinal development, however, it is not the exclusive scenario of photoreceptor differentiation. Each species must be carefully studied before deciding whether its retinal cones synthesize both pigments during retinal development.     

Effect of using prismatic eye lenses on the posture of patients with adolescent idiopathic scoliosis measured by 3-d motion analysis

This is a preliminary investigation to detect the body sway and postural changes of patients with AIS under different spatial images. Two pairs of low-power prismatic eye lenses (Fresnel prisms) with 5 dioptre and 10 dioptre were used. In the experiment, the apices of the prisms were orientated randomly at every 22.5 degrees from 0 degrees to 360 degrees to test changes. Four patients with mean age of 11 and Cobb's angle of 30 degrees were recruited and the results showed that the low-power prisms at specific orientations (157.5 degrees and 180 degrees) could cause positive postural changes (2.1 degrees-2.7 degrees reduction of angle of trunk mis-alignment) measured by 3-D motion analysis. This might be used for controlling their scoliotic curves by induced visual bio-feedback. Apart from this laboratory test, a longitudinal study is necessary to investigate the long-term effect of the prisms at different powers and orientations (under both static and dynamic situations) on the patient's posture, spinal muscular activities, vision, eye-hand coordination, psychological state and other daily activities before it becomes an alternative management of AIS.     

An autologous blood donation program for paediatric scoliosis patients in Hong Kong

A retrospective audit was conducted to determine the safety, efficacy and patient satisfaction related to a preoperative autologous blood donation program for children and teenagers undergoing corrective surgery for scoliosis. Forty-five of the 77 patients donated the requested amount of blood. These 45 compliant patients had been requested to donate fewer units of blood than noncompliant patients (mean 4.0 vs 4.6 respectively, P = 0.02). Twelve patients required allogeneic blood transfusion. Two patients had surgery delayed making the collected autologous blood unavailable. The extent of the operation was associated with the need for allogeneic blood transfusion. Six and a half percent of all donated units of blood were discarded. No major complications were reported. Overall, 93% of patients were satisfied with the program. With careful patient selection, good inter-departmental coordination and teamwork, preoperative autologous blood donation in paediatric patients undergoing extensive corrective surgery for scoliosis is safe and effective.