[Clinical characteristics, diagnosis and treatment of nasal cartilage mesenchymal hamartoma in infants].

Objective: To explore the clinical characteristics, pathological features, and diagnosis and treatment strategies of nasal chondromesenchymal hamartoma (NCMH) in infants and young children. Methods: A retrospective analysis was conducted on seven cases of NCMH infants and young children admitted to Beijing Children's Hospital, Capital Medical University from April 2015 to January 2022. The cohort included 5 males and 2 females, aged from 6 days to 2 years and 3 months. General information, clinical symptoms, imaging findings, treatment plans, postoperative complications, recurrence and follow-up time were collected, summarized and analyzed. Additionally, immunohistochemical characteristics of the lesion were examined. Results: The clinical symptoms of 7 children included nasal congestion, runny nose, open mouth breathing, snoring during sleep, difficulty feeding, and strabismus. All patients underwent electronic nasopharyngoscopy examination, with 5 cases of tumors located in the right nasal cavity and 2 cases in the left nasal cavity. No case of bilateral nasal cavity disease was found. All 7 patients underwent complete imaging examinations, with 5 patients underwent MRI and CT examinations, 1 patient underwent CT examination only, and 1 patient underwent MRI examination only. The CT results showed that all tumors were broad-based, with uneven density, multiple calcifications and bone remodeling, and some exhibited multiple cystic components. The MRI results showed that the tumor showed low signal on T1 weighted imaging and high or slightly high signal on T2 weighted imaging. All patients were diagnosed through histopathological examination and immunohistochemistry, including 7 cases of Ki-67 and SMA (+), 5 cases of S-100 and Vimentin (+), and all EMA and GFAP were negative. All patients underwent endoscopic resection surgery through the nasal approach, with 3 cases using navigation technology. Five cases of tumors were completely removed, and two cases of tumors were mostly removed. No nasal packing was performed after surgery, and no postoperative nasal, ocular, or intracranial complication occurred in all patients. Follow up assessments conducted 6 to 84 months post-surgery revealed no instances of tumor recurrence in any of the patients. Conclusions: The clinical symptoms of children with NCHM mainly depend on the size and location of the tumor. Nasal endoscopic surgery is the main treatment method. In cases where critical structures like the skull base or orbit are implicated, staged surgical interventions may be warranted. Long-term follow-up is strongly advised to monitor for any potential recurrence or complications.

[Diagnosis and management of orbital and cranial complications of pediatric acute rhinosinusitis].

Objective: To review the clinical characteristics, to illustrate diagnosis and management experience of orbital and cranial complications of pediatric acute rhinosinusitis. Methods: The clinical data of 24 children with orbital and cranial complications of acute rhinosinusitis who received endoscopic sinus surgery combined with drug treatment in Beijing Children's Hospital from January 2017 to December 2021 were retrospectively reviewed. There were 19 boys and 5 girls. The age varied from 13 to 159 months, with a median 47.5 months. The following diagnoses were obtained: 12 isolated subperiosteal orbital abscess, 2 associated with preseptal abscess, 2 associated with intraorbital abscess, 7 associated with optic neuritis, and 1 associated with septic cavernous sinus thrombosis. Clinical characteristics, organism isolated and outcomes were analyzed through descriptive methods. Results: All 24 patients presented with fever; 9 presented with nasal congestion and purulent discharge. The clinical manifestations of orbital infection included orbital edema, pain, proptosis and displacement of globe in all patients, while visual impairment was recognized in 7 children. Purulent drainage was cultured in 17 patients, among which 12 were positive. All patients underwent nasal endoscopic surgical interventions uneventfully, excluding one patient who required a second surgical procedure. Follow-up period ranged from 5 to 64 months. All patients resolved fully, with the exception of 2 children who got permanent blindness with visual loss preoperative. There was no recurrence or death. Conclusions: Orbital and cranial complications of pediatric acute rhinosinusitis could be severe with an occult onset. For patients with vison impairment, any signs of intracranial complications and a lack of response to conservative management, an urgent endoscopic intervention is needed.

[Nasal endoscopic modified mucosal flap technique for repair of congenital choanal atresia in newborns and infants].

Objective: To describe and evaluate the surgical effect and prognosis of nasal endoscopic modified mucosal flap technique for repair of congenital choanal atresia in newborns and infants. Methods: The clinical data of 38 newborns and infants with congenital choanal atresia who underwent nasal endoscopic surgery in Beijing Children's Hospital between January 2016 and May 2018 were retrospectively analysed, including 13 males and 25 females. The age ranged from 5 days to 3 years old at the time of operation (15 cases were newborns). The clinical data, imaging data, treatment effect and prognosis were collected. According to the different surgical methods, the patients were divided into the conventional operation group and the modified mucosal flap technique group. The designs of the modified mucosal flap technique were designed according to the type of congenital choanal atresia. The cross-over L-shaped flaps were performed in patients with unilateral atresia, and the mirrored L-shaped flaps were performed in patients with bilateral atresia. All the patients were followed up for 2-3 years, and the follow-up parameters included the times of operations, length of hospital stay, restenosis rate and incidence of complications. Study data was analyzed using SAS version 9.4 statistical software. Results: Sixteen cases underwent conventional operation while 22 patients underwent modified mucosal flap technique under nasal endoscope. The lightest weight (2 200 g) and the youngest age (5 days) of the patients came from the modified mucosal flap technique group. Compared with the conventional operation group under nasal endoscope, the modified mucosal flap technique group had fewer times of operations (1.14±0.47 vs 2.69±1.20, t=5.552, P<0.001), shorter hospital stay ((7.70±3.22) d vs (14.37±19.16) d, t=2.960, P=0.005), lower rate of postoperative restenosis (9.1% vs 43.8%, χ²=6.156, P=0.013), and lower rate of the incidence of complications (13.6% vs 43.8%, χ²=5.955, P=0.015), the differences were statistically significant. Conclusion: The nasal endoscopic modified mucosal flap technique is feasible for repairing congenital choanal atresia in newborns and infants, which can significantly reduce the incidence of postoperative restenosis and complications.

[Clinical efficacy of the combined diagnosis and management for children with airway allergic diseases].

Objective: To evaluate the clinical efficacy of the combined diagnosis and management in children with airway allergic diseases(bronchial asthma, allergic rhinitis). Methods: This observational study belongs to cluster sampling cases, which included the clinical data from children with airway allergic diseases in Allergy Department and Otorhinolaryngology Department of Beijing Children's Hospital from April to December in 2015. They were followed up every three months during 12 months. All the subjects were required to continuously record daily symptom by diary card. ACT/c-ACT, VAS, treatment steps to control asthma, respiratory infections, wheeze, pulmonary function(FEV1%pred,FEV1/FVC,PEF%pred,FEF25%pred,FEF50%pred,FEF75%pred,MMEF%pred), FeNO were assessed in every visiting. The mean±standard deviation was used for the measurement data in accordance with normal distribution. Comparing the pulmonary function indexes at every point, the measurement data with normal distribution and uniform variance were analyzed by single factor analysis of variance, and the measurement data with uneven variance were tested by non-parametric rank sum test. Results: Among 147 recruited participants, 106 completed the combined diagnosis and management. The airway allergic diseases control rate was 87.7% at 12 months after the combined diagnosis and management. At every point, the average daily symptom score and VAS score which were significantly lower than at the baseline(H=35.854,P=0.000)[ 1.2(0.7,2.2),0.6(0.2,1.5),0.4(0.1,1.0),0.5(0.1,1.1) vs 2.0(1.0,3.5)],(H=39.559,P=0.000)[2.5(0.5,4.7),2.2(0.3,4.4),1.8(0.2,4.6),1.6(0.3,3.8) vs 6.9(4.1,9.8)]. ACT/c-ACT score at 3, 6, 9, 12 months were significantly higher than at the baseline (H=79.695,P=0.000) [25.0(22.5,27.0),26.0(24.0,27.0),25.0(23.0,27.0),25.0(24.0,27.0) vs 20.0(17.0,22.0)]. FEV1%pred and FEF25%pred at 3, 6 months were significantly higher than at the baseline (F=3.563,P=0.007)(104.7±12.6 vs 96.8±14.5,103.0±10.3 vs 96.8±14.5),(F=2.456,P=0.046)(96.6±22.0 vs 85.0±21.9,93.3±18.0 vs 85.0±21.9). PEF%pred at 3, 6, 9, 12 months after the combined diagnosis and management were significantly higher than at the baseline(F=5.497,P=0.000)(105.1±18.1,101.2±15.3,99.7±17.1,99.8±17.5 vs 90.3±17.8). FeNO at 3, 6, 9, 12 months respectively were no significantly differences at the baseline(F=0.751,P=0.558)(25.7±23.6 vs 30.7±25.6,25.9±16.5 vs 30.7±25.6,27.5±20.2 vs 30.7±25.6,30.6±19.6 vs 30.7±25.6).The respiratory infections rate were 69.8%(74/106),67.0%(71/106),60.4%(64/106),51.9%(55/106) at 3, 6, 9, 12 months respectively. The wheezing rate was 24.5%(26/106),14.2%(15/106),11.3%(12/106),7.5%(8/106) at 3, 6, 9, 12 months respectively. Conclusions: The combined diagnosis and management can significantly improve the control level of children's airway allergic diseases, which should be implemented in the management of children's airway allergic diseases.

[Pediatric nasal neuroglial heterotopia: report of 13 cases].

Objective: To summarize clinical features and our experience of the diagnosis and treatment of pediatric nasal neuroglial heterotopia (NGH). Methods: Clinical data of 13 nasal NGH patients in Beijing Children's Hospital from August 2014 to October 2019 were retrospectively reviewed, including 9 boys and 4 girls, aged from 1 to 38 months with median age of 5 months. Radiological workups and excision of nasal NGH under general anesthesia were performed for all patients. B ultra-sound and MRI were performed for all external and mixed lesions, while ultra-low-dose CT scan and MRI for all intranasal type. Surgical approaches were dependent on location and extent of the lesions according to radiographic workup, including extranasal or transnasal endoscopic approach. Patients were followed up regularly after operation to evaluate the effect. Initial presentation, locations, imaging findings, surgical approaches and follow-up results were analyzed through descriptive statistical method. Results: Eight nasal NGH patients presented with an internal nasal mass and nasal obstruction, which belonged to intranasal type. Three patients presented with an external nasal mass which belonged to extranasal type and 2 patients had mixed lesions. The sites included nasal dorsum (n=5), anterior to the middle turbinate (n=5) and olfactory cleft (n=3). Surgical resections were done through median rhinotomy approach (n=5) or transnasal endoscopic approach (n=8). All the operations were successful and no complication occurred. All cases were followed up from 3 to 65 months. No recurrence was encountered. Conclusions: Nasal NGH is a rare lesion with atypical clinical presentation. Preoperative imaging including CT scan and MRI is essential for evaluation of the location, extent of the disease and for making the surgical plan. Treatment requires complete surgical excision.

[Excision for congenital nasal dermoid and sinus cyst in children].

Objective: To explore the surgical effect and experience of endoscope-assisted excision for congenital nasal dermoid and sinus cyst (NDSC) in children. Methods: Fifty-three patients with congenital NDSC treated in Beijing Children's Hospital from January 2007 to December 2018 were retrospectively reviewed, including 30 boys and 23 girls, with the age ranging from 9 to 145 months (mean age 35.6 months). The ultra-low-dose CT scan and MRI of the paranasal sinuses were performed for all patients. Excisions of NDSC under general anesthesia were performed for all patients, and surgical approaches were dependent on location and extent of the lesions according to radiographic workups. All intra-osseous patients and complicated superficial cases underwent surgical excision of NDSC and nasal reconstruction with the assistance of endoscope. Initial presentation, medical history, imaging workups, surgical approaches, complications, rates of recurrence and cosmetic outcomes were evaluated. Descriptive statistics was used for the results analysis. Results: Among 53 cases, the most common presentation included a nasal-glabella mass (n=21, 39.6%), a dorsal punctum (n=13, 24.5%) and a dorsal mass (n=9, 17.0%). The sites of NDSC included nasal glabella (n=22, 41.5%), nasal bridge (n=27, 50.9%) and nasal tip (n=4, 7.5%). Of all patients, 24 cases (45.3%) had superficial lesions, 19 cases (35.8%) had intraosseous extension into the frontonasal bones, 10 cases (18.9%) extended intracranially but remained extradural. Surgical approaches included transverse incision (n=22, 41.5%), minimal midline vertical incision (n=27, 50.9%) and external rhinoplasty (n=4, 7.5%). All NDSC were successfully excised and no nasal reconstruction needed. All cases were followed up from 9 to 151 months with a mean of 67.3 months. Five patients (9.4%) with recurrence were observed and were managed successfully with reoperation. During the follow-up, no nasal deformity was noted, and cosmetic outcome was favorable for all patients. Conclusion: Endoscope-assisted excision has the advantage of clear vision, small trama and low recurrence rate for children with NDSC.

Novel long non-coding RNA LBX2-AS1 indicates poor prognosis and promotes cell proliferation and metastasis through Notch signaling in non-small cell lung cancer.

OBJECTIVE: Recent reports have suggested that long non-coding RNA LBX2 antisense RNA 1 (LBX2-AS1) acts as an important regulator in cancer progression. This study aimed to investigate the clinical significance of LBX2-AS1 in non-small cell lung cancer (NSCLC) patients and its biological functions. PATIENTS AND METHODS: The expressions of LBX2-AS1 were examined in 165 paired NSCLC tissues and adjacent normal tissues from NSCLC patients by qRT-PCR. The clinical significance of LBX2-AS1 was determined using a series of statistical methods. The effects of LBX2-AS1 knockdown on NSCLC cell proliferation, migration, and invasion were investigated by CCK-8 assays, colony formation assays, EdU proliferation assays, Wound healing assays, and transwell assays. The promotive roles of LBX2-AS1 on Notch1 signal were determined using RT-PCR and Western blot. RESULTS: We found that LBX2-AS1 was highly expressed in NSCLC tissues and cell lines. The increased levels of LBX2-AS1 were observed to be positively correlated with TNM stage, histological grade, and lymph node metastasis. Furthermore, the Kaplan-Meier survival curves indicated that patients with higher expressions of LBX2-AS1 had unfavorable overall survival. Lost-of-functions assays revealed that the knockdown of LBX2-AS1 in H1299 and A549 cells inhibited cell proliferation, migration, and invasion. Mechanistic studies revealed that the suppression of LBX2-AS1 resulted in the reduced expressions of Notch1, p21, and Hes1, suggesting that LBX2-AS1 might promote the activation of the Notch pathway. CONCLUSIONS: Our study identified a novel NSCLC-related lncRNA LBX2-AS1, which may represent a novel prognostic biomarker and a potential therapeutic target for NSCLC.

NAKα2 inhibits fibrosis formation and protects against cardiomyocyte hypertrophy by suppressing hypertrophy associated molecules and activating LTCC/NCX signaling pathway.

OBJECTIVE: Cardiomyocyte hypertrophy is considered to be a compensatory process of heart suffering from pathological damages. This study aimed to evaluate effects of Na+/K+ APTaseα2 (NAKα2) on isoprenaline (ISO) induced cardiomyocyte hypertrophy. MATERIALS AND METHODS: Mouse atrial cardiomyocytes were cultured and treated with ISO to establish cardiomyocyte hypertrophy model. NAKα2 over-expression and small interfere RNA (siRNA) plasmids were constructed and transfected to cardiomyocytes. Influx Ca2+ ([Ca2+]i) was measured using flow cytometry method. Fibrosis formation was examined with Masson staining. Transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) staining was used to examine apoptosis. Major histocompatibility complex ß (ß-MHC), atrial natriuretic peptides (ANP), B-type natriuretic peptides (BNP) were evaluated with quantitative Real-time PCR (qRT-PCR). Western blot was used to detect ß-MHC, ANP, BNP, Na+/Ca2+ exchanger (NCX) and L-type calcium channel (LTCC). RESULTS: NAKα2 significantly inhibited NCX and LTCC expression compared to that in ISO-treated cardiomyocytes (p<0.05). NAKα2 significantly suppressed expression of ß-MHC, ANP and BNP compared to that in ISO-treated cardiomyocytes (p<0.05). NAKα2 significantly alleviated fibrosis formation and inhibited apoptosis compared to that in ISO-treated cardiomyocytes (p<0.05). NAKα2 reduced intracellular calcineurin and activated phosphorylation of calcineurin-nuclear factor of activated T cells (NFAT) compared to ISO-treated cardiomyocytes (p<0.05). NAKα2 significantly strengthened effects of Klotho on ISO-induced up-regulation of hypertrophy associated molecules (p<0.05) by activating LTCC and NCX. Comparing to ISO-treated cardiomyocytes, NAKα2 combining Klotho treatment exhibited significantly better improvement of Ca2+ influx, alleviation of fibrosis and reduction of apoptosis by triggering LTCC/NCX signaling pathway. CONCLUSIONS: Over-expression of NKAα2 suppressed fibrosis formation and protected against cardiomyocyte hypertrophy by inhibiting hypertrophy associated molecules, alleviating apoptosis and activating LTCC/NCX signaling pathway.

Efficacy and safety of sublingual immunotherapy with Dermatophagoides farinae drops in pre-school and school-age children with allergic rhinitis.

BACKGROUND: The safety and efficacy of sublingual immunotherapy (SLIT) have been confirmed by many studies. However, in China, the research on efficacy and safety in young and older children with allergic rhinitis (AR) is still rare. OBJECTIVE: The aim of this retrospective study is to evaluate the efficacy and safety of SLIT with Dermatophagoides farinae drops in pre-school and school-age children with AR. METHODS: A total of 282 subjects aged 2-13 years with AR received a two-year course of sublingual immunotherapy along with pharmacotherapy. According to the age, patients were defined as the pre-school group (2-6 years old, n=116) and school-age group (7-13 years old, n=166). Total nasal rhinitis symptom scores (TNSS), visual analogue score (VAS) and total medication scores (TMS) were evaluated at four time points: baseline, after SLIT for half a year, one year and two years. The adverse events (AEs) were evaluated at each visit. RESULTS: After two-year SLIT, the four rhinitis symptom scores, TNSS, VAS and TMS scores were significantly lower than baseline (all P<0.05). The comparison of efficacy between one and two-year duration showed no significant difference in global clinical outcomes (all P>0.05). In addition, there were no significant differences between the pre-school and school-age group in TNSS (all P>0.05), VAS (all P>0.05) and TMS scores (P>0.05) after SLIT for half a year, one year and two years. No severe systemic AEs were reported. CONCLUSION: SLIT with D. farinae drops is clinically effective and safe in pre-school and school-age patients with house dust mites (HDMs)-induced AR.

[Budesonide saline nasal irrigation in treatment of children rhino-sinusitis].

Objective:To study the effect of nasal irrigation in treatment of children rhinosinusitis.To compare the effect with different nasal irrigation methods and nasal spray with budesonide.Method:Seventy-five patients with rhinosinusitis were divided randomly into four groups.Nasal irrigation with saline(20 cases),treated with budesonide nasal spray(20 cases),nasal irrigation with saline and budesonide(20 cases),nasal spray with 2.3% hypertonic saline (15 cases).Saccharin clearance time,physical examination of the nose and the quality of life were used to evaluate the efficiency at the beginning of the treatment,one and two weeks after the treatment,respectively.Result:After the therapy,the index of saccharin clearance time,physical examination of the nose and the quality of life were improved in each group.The budesonide and normal saline group is the greatest one.And then,the efficiency of treatment is budesonide nasal spray group >the 2.3% hypertonic saline group>the normal saline group.The differences between each group were significant.Conclusion:Nasal irrigation is a useful treatment in children rhinosinusitis.The efficiency of saline irrigation is less than budesonide aerosol spray.Add budesonide to the irrigation fluid combines the effect of the budesonide with irrigation and get more efficiency of treatment.

Lipid peroxidation and platelet activation in murine atherosclerosis.

BACKGROUND: Lipid peroxidation and platelet activation are thought to be important contributors to the pathogenesis of atherosclerosis. The relevance of their interaction in vivo, however, is unknown. METHODS AND RESULTS: LDL receptor-deficient (LDLR(-/-)) mice on a high-fat diet developed extensive atherosclerosis and had increased urinary levels of 8,12-iso-isoprostane (iP) F(2alpha)-VI and 2,3-dinor-thromboxane (Tx) B(2), markers of in vivo lipid peroxidation and platelet activation, respectively. Vitamin E supplementation suppressed 8,12-iso-iPF(2alpha)-VI biosynthesis and reduced atherosclerosis (65%) without having a significant effect on lipid levels or TxB(2) biosynthesis. Addition of the platelet inhibitor indomethacin to vitamin E simultaneously suppressed 8,12-iso-iPF(2alpha)-VI and TxB(2), significantly reduced soluble intercellular adhesion molecule-1 and monocyte chemoattractant protein-1, and remarkably, further reduced atherosclerosis (80%). CONCLUSIONS: These results indicate that in vivo lipid peroxidation and platelet activation coexist in murine atherosclerosis and that lipid peroxidation does not contribute to platelet activation and reflects the oxidant component of the inflammatory response. Our findings suggest that oxidant stress and platelet activation represent 2 distinct therapeutic targets in atherogenesis. We propose that a combination of antioxidants and platelet inhibitors might be rationally evaluated in the prevention of progression of human atherosclerosis.

Serum free light-chain measurements for identifying and monitoring patients with nonsecretory multiple myeloma.

Using sensitive, automated immunoassays, increased concentrations of either kappa or lambda free light chains (and abnormal kappa/lambda ratios) were detected in the sera of 19 of 28 patients with nonsecretory multiple myeloma. Four other patients had suppression of one or both light chains, and the remaining 5 sera had normal or raised free light-chain concentrations with substantially normal kappa/lambda ratios. Six of the patients with an elevated single free light chain, who were studied during follow-up, had changes in disease activity that were reflected by the changes in free light-chain concentrations. It is concluded that quantification of free light chains in serum should prove useful for the diagnosis and monitoring of many patients with nonsecretory myeloma.

Highly sensitive, automated immunoassay for immunoglobulin free light chains in serum and urine.

BACKGROUND: Bence Jones proteins or monoclonal immunoglobulin kappa and lambda free light chains (FLCs) are important markers for identifying and monitoring many patients with B-cell tumors. Automated immunoassays that measure FLCs in urine and serum have considerable clinical potential. METHODS: Sheep antibodies, specific for FLCs, were prepared by immunization with pure kappa and lambda molecules and then adsorbed extensively against whole immunoglobulins. The antibodies were conjugated onto latex particles and used to assay kappa and lambda FLCs on the Beckman IMMAGE protein analyzer. RESULTS: The unconjugated antibodies showed minimal cross-reactivity with intact immunoglobulins or other proteins. With latex-conjugated antibodies, kappa and lambda FLCs could be measured in normal sera and most normal urine samples. Patients with multiple myeloma had increased concentrations of the relevant serum FLC, whereas both FLCs were increased in the sera of patients with systemic lupus erythematosus. CONCLUSIONS: We developed sensitive, automated immunoassays for kappa and lambda FLC measurements in serum and urine that should facilitate the assessment of patients with light chain abnormalities.

Down's syndrome is associated with increased 8,12-iso-iPF2alpha-VI levels: evidence for enhanced lipid peroxidation in vivo.

Postmortem and in vitro studies have shown that oxidative stress plays a role in the pathogenesis of many of the clinical features of Down's syndrome. The isoprostane 8,12-iso-iPF2alpha-VI is a specific marker of lipid peroxidation. We found elevated levels of this isoprostane in urine samples of subjects with Down's syndrome compared with those of matched controls, which correlated with the duration of the disease. These results suggest that increased in vivo lipid peroxidation is a prominent component early in the course of Down's syndrome.

Effects of additional iron-chelators on Fe(2+)-initiated lipid peroxidation: evidence to support the Fe2+ ... Fe3+ complex as the initiator.

The addition of chelated Fe2+ ions in a liposomal system often results in a short lag period before peroxidation starts. The addition of a second chelator at the end of the lag period results in an inhibition of the lipid peroxidation. The degree of inhibition depends on the stability constants of the chelator in ligating Fe2+ and/or Fe3+. A more striking inhibitory effect was observed for the chelators with higher stability constant for either or both Fe(2+)- and Fe(3+)-complex, but much less inhibition was found for those with lower stability constants for both complexes. Assuming that the "initiator" for iron-dependent lipid peroxidation is formed through the redox process of iron ion and finally emerged at the end of the latent period, the inhibitory effect of the second chelator may be explained as the abstraction of either Fe2+ or Fe3+ from the initiator by an additional free chelator, which results in the decomposition of the initiator. This study supports the hypothesis that a Fe2+ ... Fe3+ complex is responsible for iron-initiated lipid peroxidation.

Effects of lead on temporal response properties of retinal ganglion cells in developing rats.

Neonatal rats have taken in lead, during the period from their parturition to their weaning, from the milk of dams fed with water containing 0.2% lead acetate solutions. The alterations in the temporal response properties of retinal ganglion cells in adult rats (90 days) following the lead exposure at their developing stage have been studied. The results of this investigation demonstrate that the lead exposure in neonatal rats causes decreases in the optimal temporal frequency, bandwidth at half amplitude, temporal resolution and response phase of the retinal ganglion cells in adult rats. Compared with the sustained cells, the transient cells have a much greater alteration in temporal response properties.

Effects of low-level lead on retinal ganglion sustained and transient cells in developing rats.

Neonatal rats were exposed to lead from parturition to weaning via the milk of dams drinking 0.2% lead acetate solutions. The alterations in the excitability and temporal response properties of retinal ganglion cells in adult rats (90 days) following developmental lead exposure were studied. The results of this investigation demonstrated that the lead exposure in neonatal rats caused an increase in excitability, and a decrease in optimal temporal frequency, bandwidth at half amplitude, temporal resolution, and response phase of the retinal ganglion cells in adult rats. Compared with the sustained cells, the transient cells had a much greater alteration in excitability and temporal response properties.

Optimisation of enzyme electrodes.

Enzyme electrodes have been fabricated in a variety of ways and used successfully for aqueous solution measurement. Knowledge about the fundamental basis of their operation has increased substantially in recent years, but the final, partly technological, hurdle of adaptation for practical use remains to be fully surmounted. Key aspects requiring attention are dependence on solution parameters capable of changing the kinetics of the immobilised enzyme reaction, direct fouling at the enzyme electrode, and the distorting effect of the biological matrix, notably blood and tissue, on the electrode environment due to the deposition of surface-active macromolecules and cellular elements. This review of enzyme electrode optimisation deals primarily with the various membranes which have been used to try to overcome such highly practical limitations to the biomedical use of enzyme electrodes. The classical amperometric glucose electrode based on detection of H2O2/O2 by the underlying sensor will be emphasised, but pH-based sensors for pyruvate and urea will also be discussed. The amperometric systems described indicate that with appropriate covering membranes, many, though by no means all, interfacing problems can be overcome, and also that the type of optimisation engineered is dictated by the specific application envisaged.

The needle glucose electrode: in vitro performance and optimisation for implantation.

The classical glucose needle electrode based on detection of H2O2 from glucose oxidase has been studied. Dip-coating of a series of outer polyurethane layers of increasing concentration (10-50% W/V) achieved devices with extended linearity (greater than or equal to 30 mM glucose) with greater reliability than a single dip-coat. In vitro performance in unstirred whole blood was acceptable, and all devices were stir-independent. Nevertheless, signal size was affected by a high solution viscosity, and this may have implications for the use of enzyme electrodes in subcutaneous tissue.