Prevalence and Risk Factors for Obstructive Sleep Apnea Syndrome Among Children and Adolescents with Cleft lip and Palate: A Survey Study in Hong Kong.

OBJECTIVE: To investigate the prevalence of obstructive sleep apnea syndrome (OSAS) risk and related risk factors among children and adolescents of Hong Kong with cleft lip and/or palate (CL/P). DESIGN: Retrospective survey study adopting three questionnaires, obstructive sleep apnea-18 (OSA-18), pediatric sleep questionnaire-22 (PSQ-22), and modified Epworth Sleepiness Scale (ESS). SETTINGS: Multicenter study in two public hospitals. PATIENTS: A total of 351 Chinese children and adolescents with non-syndromic CL/P (6-18-year-old, 57% males) visited between September 2017 and November 2019, with primary palatal repair surgery done before 3-year-old. MAIN OUTCOME MEASURE: Positive OSAS risk was determined based on cut-off ≥60 for OSA-18, ≥8 for PSQ-22, and >8 for ESS. Age, sex, overweight presence, cleft type, embryonic secondary palate involvement, palatal repair surgery, palatal revision surgery, and orthodontic treatment were analyzed as possible risk factors. RESULTS: A total of 9.5% of patients had positive OSAS risk based on OSA-18, 13.6% based on PSQ-22, and 13.2% according to ESS. A higher prevalence of patients with positive OSAS risk was of younger age (OSA-18, p = .034), had cleft involving embryonic secondary palate (PSQ-22, p = .009), and history of fixed orthodontic treatment (ESS, p = .002). The regression model identified only involvement of embryonic secondary palate as a risk factor (PSQ-22, odds ratio = 3.7, p = .015). CONCLUSIONS: OSAS risk among children and adolescents of Hong Kong with CL/P was 9.5% to 13.6%. Patients at higher risk were those with cleft involving embryonic secondary palate. OSAS risk assessment may be influenced by different aspects of the disease spectrum, and a multimodal approach should be considered for such assessment.

Orthodontic plate for management of obstructive sleep apnoea in infants with Pierre Robin sequence: experience and protocol in Hong Kong.

OBJECTIVE: To present the application of the pre-epiglottic baton plate (PEBP) in infants with Pierre Robin sequence (PRS) in the Southern Chinese population (Hong Kong) and to present the diagnosis and management protocol of these infants in our centre. DESIGN: Retrospective case series of three patients with PRS. SETTING: Neonatal Intensive Care Unit in Kwong Wah Hospital and Craniofacial Orthodontic Centre in United Christian Hospital, Hong Kong. PARTICIPANTS: Three new-born infants (two girls, one boy) with PRS and upper airway obstruction due to glossoptosis. METHODS: A protocol for the diagnosis and management of these infants in the Southern Chinese population (Hong Kong) was presented. The three patients received nasal high-flow oxygen and/or continuous positive airway pressure (CPAP) as first-line respiratory support, followed by PEBP for 3-5 months. A two-stage approach was undertaken to ensure accurate positioning of the PEBP. RESULTS: All three infants had improvement in clinical signs, symptoms and polysomnography upon discharge. PEBP and other respiratory aids were weaned off at 3-6 months. CONCLUSIONS: The PEBP, combined with other respiratory support, is a useful modality in the treatment of obstructive sleep apnoea in infants with PRS.

Strong interactions in supported-metal catalysts.

Many commercially important catalysts consist of small metal particles dispersed on inorganic oxide surfaces. Although in most cases there is no significant interaction between the metal and the support, strong bonding can be demonstrated in a recently discovered class of supported-metal catalysts. These cases typically involve group VIII metals dispersed on transition metal oxides whose surfaces can be reduced to form cations with lower valences. Spectroscopic measurements indicate that an electron is transferred from the cation (such as Ti(3+) or Nb(4+)) to the metal particle. This, in turn, leads to profound changes in the catalytic and chemisorption properties and the morphology of the metal particles.

Epidemiology and outcome of Candida bloodstream infection in an intensive care unit in Hong Kong.

OBJECTIVE: To study the epidemiology of Candida bloodstream infection in the Intensive Care Unit. DESIGN: Retrospective study. SETTING: A 22-bed, mixed medical and surgical Intensive Care Unit of a 1400-bed university teaching hospital in Hong Kong. PATIENTS: All adult patients (>18 years) who had at least one blood culture positive for Candida. RESULTS: During the 9 years of the study period, there were 128 patients with episodes of candidaemia (point prevalence, 9.6 per 1000 Intensive Care Unit admissions), 72 entailed albicans candidaemia and 56 non-albicans candidaemia. Albicans was still the predominant species, but the incidence of tropicalis was increasing. The median lengths of hospital and Intensive Care Unit stays prior to taking of the culture revealing candidaemia were 15 and 6 days, respectively. In all, 61% of patients did not have Candida colonisation within 2 weeks of their candidaemia. The main anti-fungal agents used were fluconazole and amphotericin B, but only 89 (70%) of the patients received appropriate anti-fungal treatment. Intensive Care Unit and hospital mortalities were 70% and 78%, respectively. Patients who did not receive appropriate treatment within 3 days had a worse outcome than those who did. CONCLUSIONS: Our data showed a high point prevalence of candidaemia in the Intensive Care Unit. Albicans was still the predominant species. Candidaemia occurred early during Intensive Care Unit stay, and a significant proportion of patients did not have prior fungal colonisation. Candidaemia in the Intensive Care Unit was associated with high morbidity and mortality. Many patients did not receive appropriately early anti-fungal therapy, and endured higher mortality than in the remainder.

Lifetime prevalence of suicide ideation, plan, and attempt in metropolitan China.

OBJECTIVE: This is the first community-based epidemiological study examining the prevalence of suicidal behaviors, their transitional pathways, and their relationship with mental disorders in metropolitan China. METHOD: Suicidal behaviors, including ideation, plans, and attempts were assessed by face-to-face household interviews among 5201 respondents in Beijing and Shanghai in 2001-2002. Lifetime prevalence and risk factors were examined using multivariate discrete-time survival models. RESULTS: The lifetime prevalence estimates of suicidal ideation, plans, and attempts were 3.1%, 0.9%, and 1.0% respectively. Among suicide ideators, the conditional probability of ever making a plan and an attempt was 29.5% and 32.3% respectively. Progression from ideation to plan and attempt was the highest during the first year after onset. Suicide attempt was predicted by young adulthood, being unmarried, recent onset of ideation and plan, and the presence of mental disorders, especially mood disorder. CONCLUSION: Suicidal behaviors in metropolitan China exhibit a low prevalence and an epidemiological profile resembling that found in Western countries.

Postnatal development of GABA-ergic neurons in the rabbit retina.

Uptake, synthesis, storage, and release of gamma-aminobutyric acid (GABA) are some of the characteristic properties of GABA-ergic neurons. In the present study, we have used these properties as physiological probes to follow the emergence and maturation of GABA-ergic neurons during postnatal development of the rabbit retina. There is autoradiographic, immunocytochemical, and pharmacological evidence that some amacrine cells and certain neurons in the ganglion cell layer probably use GABA as the neurotransmitter. These neurons take up GABA, contain the GABA-synthesizing enzyme L-glutamic acid decarboxylase (GAD, EC 4.1.1.15), and release the accumulated GABA by a CA++-dependent mechanism when depolorized with high extracellular K+ concentration. In this study, we show that certain neurons in the newborn retina already possess a specific mechanism for GABA uptake. The positions and numbers of these cells in the developing retina suggest that they will become GABA-ergic neurons in the adult retina. These putative GABA-ergic neurons are, however, probably immature at birth because newborn retinas contain only low levels of GABA and GAD. Additionally, there is relatively little K+-stimulated, Ca++-dependent release of (3H)-GABA from the newborn retinas. GABA concentrations and GAD activities in developing retinas increase steadily postnatally, reaching about 80% of the adult levels by day 9. The activities of the GABA-degrading enzyme, GABA-glutamate transaminase (GABA-T, EC 2.6.1.19), follow a similar pattern of maturation during retinal development. K+ stimulated GABA release, however, remains low until about day 6, and then increases dramatically from 20% to 85% of the adult level over the next 3 days. Taken together, our results indicate that in the rabbit retina, the commitment by certain neurons to use GABA as the transmitter is made prenatally. These neurons are immature at birth but are biochemically, physiologically, and probably functionally mature by about 9 days after birth.

Postnatal development of glycinergic neurons in the rabbit retina.

Certain neurons in the adult rabbit retina possess a high-affinity uptake mechanism for glycine and release it in response to elevated K+ concentrations in the medium. Although the evidence is not yet complete, these properties, together with pharmacological studies, suggest that the glycine-accumulating neurons may be a subpopulation of amacrine cells and may use glycine as a neurotransmitter. In the present study, we have used the uptake and K+-stimulated release of glycine as physiological probes to follow the emergence and maturation of putative glycinergic neurons during postnatal development of the rabbit retina. We show that certain neurons in the newborn retina already possess a specific high-affinity mechanism for glycine uptake. The positions and density of these cells in the developing retina suggest that they will become glycine-accumulating neurons of the adult retina. Thus, similar to our earlier study on the development of GABA-ergic neurons in this retina, the commitment by certain retinal neurons to be glycinergic, if indeed these cells use glycine as the transmitter, is made prenatally. These putative glycinergic neurons are, however, probably immature at birth, because they do not release the accumulated glycine in response to high K+ concentrations in the medium. In fact, there is practically no K+-stimulated release of preloaded glycine from the retina until about 7 days after birth, after which the release increases drastically to about 65% of the adult level on day 10 and 80% on day 12. Assuming that this release originates synaptically, our finding suggests that the putative glycinergic neurons may be functionally mature by 10-12 days after birth. Additionally, our results show that during development of the rabbit retina, the mechanism for high-affinity glycine uptake emerges and matures much earlier than the mechanism for K+-stimulated glycine release.

The actions of barbiturates on release of noradrenaline from rat hippocampal synaptosomes.

Barbiturates are believed to work both by augmenting GABA action and independently perhaps by decreasing neurotransmitter release. By studying the effect of pentobarbitates on the release of 3H noradrenaline from rat hippocampal synaptosomes it was found that pentobarbitone (10(-6)M and 10(-5)M) augmented the GABA evoked release of 3H noradrenaline but 10(-4)M depressed this GABA effect. This latter concentration of pentobarbitone also depressed the K+-evoked release of 3H noradrenaline by a Ca++ dependent but picrotoxin insensitive mechanism.

Studies on the mechanism of modulation of [(3)H]noradrenaline release from rat hippocampal synaptosomes by GABA and benzodiazepine receptors.

Release of [(3)H]noradrenaline from rat hippocampal synaptosomes was triggered by pulses of 25 mM K(+), 5 ?M veratridine or superfusion with the Ca(2+) ionophore A23187. GABA with bicuculline or chlordiazepoxide depressed the release of [(3)H]noradrenaline evoked by depolarisation but not by the Ca(2+) ionophore. 8 Br-cAMP with [Ca(2+)](0) 0.3 mM had no effect on spontaneous or K(+)-evoked release of [(3)H]noradrenaline and completely blocked the effect of chlordiazepoxide and GABA with bicuculline. With [Ca(2+)](0) 1 mM 8 Br-cAMP enhanced spontaneous and K(+)-evoked release of [(3)H]noradrenaline, and reversed the depression caused by GABA with bicuculline. GABA alone evoked Ca(2+)-dependent release of [(3)H]noradrenaline which was sensitive to [Cl(?)](0). The results suggest that the GABA(A)-receptor mediated release of [(3)H]noradrenaline is due to depolarisation resulting from increased Cl(?) conductance whereas the depression of depolarisation-dependent release of [(3)H]noradrenaline by GABA(B) or benzodiazepine receptors is mediated by a cAMP-dependent decrease in the voltage-dependent Ca(2+) conductance.

Effect of baclofen on in vitro noradrenaline release from rat hippocampus and cerebellum: an action at an ?(2)-adrenoceptor.

The release of [(3)H]noradrenaline from rat hippocampal synaptosomes by 25 mM K(+) and 5 ?M veratridine, but not by the Ca(2+) ionophore A23187 was depressed by baclofen. This depression was reversed by 8-Bromo-cAMP. This action of baclofen was stereospecific and mimicked both that of GABA in the presence of bicuculline and that of clonidine. The ?(2)-adrenoceptor antagonists yohimbine and Wy25309 antagonised the action of clonidine and baclofen but not that of GABA. Specific binding of [(3)H]clonidine was displaced by Wy25309 and baclofen, but not by GABA. Specific binding of [(3)H]GABA in the presence of Ca(2+) was displaced by baclofen but not by Wy25309. It is concluded that baclofen is not a specific agonist at GABA(B) receptors in the brain.

The role of pre-synaptic GABA and benzodiazepine receptors in the control of noradrenaline release in rat hippocampus.

Noradrenaline release from synaptosomes of rat hippocampus is modulated by both GABA and benzodiazepines. GABAA and GABAB receptors are present on these nerve terminals, and agonists at these receptors enhance spontaneous release and depress K+ -evoked release, respectively. Chlordiazepoxide has a dual effect: it enhances the action of GABA at GABAA receptors and depresses K+ -evoked release of [3H]noradrenaline in the absence of GABA. The mechanism of these actions and their in vivo role are discussed.

Multiple effects of drugs acting on benzodiazepine receptors.

The actions on [3H]noradrenaline release of chlordiazepoxide and FG 7142 were investigated in rat hippocampal synaptosomes. The release evoked by GABA, an action mediated by GABAA receptors, was enhanced by chlordiazepoxide and depressed by FG 7142. K+-evoked release, however, was depressed by both chlordiazepoxide and FG 7142 and occurred in the absence of GABA. The actions on both GABA-evoked and K+-evoked release were blocked by Ro 15-1788. The results suggest that the distinction between agonist and inverse agonist applies to the GABA-dependent but not to the GABA-independent action of benzodiazepines.

The epidemiology of leprosy in a high prevalence village in Papua New Guinea.

In a village of about 1000 people in Papua New Guinea the prevalence of clinical leprosy was 8.6% compared to about 3% in surrounding villages. This exceptionally high prevalence could not be explained by recent introduction of the disease or by social factors. Dapsone-resistant disease and faulty compliance with treatment are considered to be contributory to persistent infectivity of old cases which, together with the presence of 20 previously undiagnosed cases, comprised a large infective source. Social ostracism of cases was not observed and the extensive social mixing of all ages would facilitate widespread dissemination of infection. A high prevalence, particularly in children, of elevated levels of IgM antibody to phenolic glycolipid-1 Mycobacterium leprae specific antigen suggests frequent subclinical infection. The greater prevalence of clinical leprosy following childhood in the village favours altered susceptibility following exposure in childhood. There was a higher prevalence of leprosy in close relatives of cases when compared with the same relatives of age and sex matched leprosy-free controls. The occurrence of familial clustering of leprosy in a hyperendemic area with intense transmission suggests that unidentified inherited factors influence susceptibility to clinical leprosy. It is suggested that the clustering of adverse inherited traits through intermarriage may explain this hyperendemic focus on leprosy.

Double blind, randomised, placebo controlled study of oral vancomycin in prevention of necrotising enterocolitis in preterm, very low birthweight infants.

AIMS: To evaluate the effectiveness of oral vancomycin in the prophylaxis of necrotising enterocolitis in preterm, very low birthweight infants. METHODS: A prospective, double blind, randomised, placebo controlled study in a tertiary referral centre of a university teaching hospital was conducted on 140 very low birthweight infants consecutively admitted to the neonatal unit. The babies were randomly allocated to receive oral vancomycin (15 mg/kg every 8 hours for 7 days) or an equivalent volume of placebo solution. Prophylaxis was started 24 hours before the start of oral feeds. All suspected cases of necrotising enterocolitis were investigated with a full sepsis screen and serial abdominal radiographs. Necrotising enterocolitis was diagnosed and staged according to modified Bell's criteria. RESULTS: Nine of 71 infants receiving oral vancomycin and 19 of 69 infants receiving the placebo solution developed necrotising enterocolitis (p = 0.035). Infants with necrotising enterocolitis were associated with a significant increase in mortality (p = 0.026) and longer duration of hospital stay (p = 0.002). CONCLUSIONS: Prophylactic oral vancomycin conferred protection against necrotising enterocolitis in preterm, very low birthweight infants and was associated with a 50% reduction in the incidence. However, widespread implementation of this preventive measure is not recommended, as it would only be effective in necrotising enterocolitis caused by Gram positive organisms and could increase the danger of the emergence of vancomycin resistant or dependent organisms. Its use should be restricted to a high prevalence nursery for a short and well defined period in a selected group of high risk patients.

Posterior maxillary anatomy: implications for Le Fort I osteotomy.

The most common site of haemorrhage in maxillary osteotomies is the posterior maxilla. Better understanding of the anatomy in this region may minimize possible vascular complications. The aim of the study was to study the osteology of the posterior maxillary region and establish clinical safety guidelines for the Le Fort I osteotomy Thirty human dry skulls were selected and assessed by a combination of direct inspection, computerized imaging and computed tomography (CT) scan analysis. Results showed that the presence of maxillary third molars influenced the transverse angulation of the posterior vertical cut. Synostosis of the pterygomaxillary junction was noted in 12% of samples. The mean length of the medial sinus wall from the piriform rim to the descending palatine canal at the Le Fort I level was 34 mm. The three-dimensional CT-reconstructed descending palatine canal ran at 60 degrees anteroinferiorly to the palatine plane and slightly medially to the exit through the greater palatine foramen.

Intra-operative blood loss and operating time in orthognathic surgery using induced hypotensive general anaesthesia: prospective study.

We investigated the average operating time and extent of intra-operative blood loss in orthognathic surgeries performed using induced hypotensive general anaesthesia, with the intention of devising a practical guideline for blood unit preparation for these procedures. We prospectively studied 32 Chinese patients undergoing surgery to correct dentofacial deformities at a public hospital in Hong Kong from 1 December 1997 to 1 December 1998. Most patients (72. 4%) needed double-jaw surgery. The mean estimated blood loss was approximately 617.6 mL. The blood loss during simple Le Fort I osteotomies was about half that of multiple segmentalised osteotomies. For mandibular ramus osteotomies, the mean blood loss and operating time for were approximately 280 mL and 2 hours, respectively; for anterior mandibular osteotomies, the corresponding values were 171.3 mL and 1 hour 13 minutes. The average drop in the haematocrit value was 15.4%, and the crossmatch to transfusion ratio was 29. A bivariate correlation test between the blood loss and operating time gave a strong correlation (P<0.01), as did blood loss with a drop in haematocrit value (P<0.01). Orthognathic surgeries are thus safe and predictable in terms of intra-operative blood loss and operating time, and a 'type, screen, and save' policy for blood unit preparation is more appropriate than a 'crossmatch' policy.

Comparison of two techniques of patient-controlled sedation with midazolam.

OBJECTIVE: To compare patient-controlled sedation with 1-mg increments of midazolam at 1-min intervals with 0.1-mg increments of midazolam without a lock-out interval. DESIGN: Randomized cross over study. SUBJECTS: 32 patients aged 17-35 years having third molars removed. RESULTS: Doses of midazolam obtained, degree of sedation and operating conditions were similar in the two groups. The demands far exceeded the increments actually received by patients obtaining 0.1-mg increments. Some were extremely sedated with both techniques. CONCLUSIONS: In this age group, there were no significant advantages or disadvantages of one technique over the other. Patients obtained the degree of sedation they required to undergo the operation by pressing the button independently of the dose or incremental interval. So-called 'true' patient-controlled sedation is a misnomer. The cut-off interval proved to be an extremely important safety feature.