Congenital cholesteatoma: what radiologists need to know

Congenital cholesteatoma is a rare, non-neoplastic lesion that causes conductive hearing loss in children. It is underrecognized and often diagnosed only when there is an established hearing deficit. In the pediatric population, hearing deficiency is particularly detrimental because it can impede speech and language development and, in turn, the social and academic well-being of affected children. Delayed diagnosis leads to advanced disease that requires more extensive surgery and a greater chance of recurrence. A need to promote awareness and recognition of this condition has been advocated by clinicians and surgeons, but no comprehensive imaging review dedicated to this entity has been performed. This review aims to discuss the diagnostic utility of high-resolution computed tomography and magnetic resonance imaging in preoperative and postoperative settings in congenital cholesteatoma. Detailed emphasis is placed on the essential preoperative computed tomography findings that facilitate individualized surgical management and prognosis in the pediatric population.

Hybrid Magnetic Resonance Imaging with Single Photon Emission Computed Tomography/Computed Tomography Bone Scan for Diagnosis Of Avascular Necrosis of Femoral Head

Magnetic resonance imaging (MRI) is a commonly used imaging modality to detect early avascular necrosis (AVN). When MRI is inconclusive, bone scan is helpful in detecting AVN during early phase of the disease. As newer nuclear medicine equipment, such as single photon emission computed tomography/computed tomography (SPECT/CT) and positron emission tomography, are emerging in medical science, the role of these imaging modalities in AVN of femoral head is re-evaluated.

Epidemiology of respiratory syncytial virus infection and its effect on children with heart disease in Hong Kong: a multicentre review

OBJECTIVES

There is no guideline in Hong Kong regarding respiratory syncytial virus (RSV) immunoprophylaxis for children with heart disease because of a lack of local data on RSV infection. Therefore, this study evaluated the epidemiology and impact of RSV infection on children with heart disease in Hong Kong, with the goal of providing recommendations regarding RSV immunoprophylaxis.

METHODS

This multicentre retrospective case-control study on paediatric RSV infection was conducted in four local regional hospitals from 2013 to 2015. The patients' demographic and clinical data were retrieved and analysed.

RESULTS

There were 3538 RSV hospitalisations during the study period, and the mortality rate was 0.14%. Some RSV seasonality was present in Hong Kong, primarily in spring and summer. Respiratory syncytial virus infection was positively correlated with relative humidity and negatively correlated with wind speed and atmospheric pressure. Patients with heart disease had a more severe outcome than those without, including longer median hospital stay (4 vs 2 days, P<0.001), higher complication rate (28.6% vs 9.8%, P<0.001), and higher rates of intensive care (11.6% vs 1.4%, P<0.001) and mechanical ventilation (3.6% vs 0.4%, P=0.003). Complications in non-cardiac patients included myocarditis and Kawasaki disease. Predictors of severe RSV infection in patients with heart disease were heart failure, pulmonary hypertension, and severe airway abnormalities associated with congenital heart disease.

CONCLUSIONS

Respiratory syncytial virus infection occurs mainly in spring and summer in Hong Kong, and is related to meteorological conditions. Respiratory syncytial virus infection poses a heavy disease burden on children with heart disease. A local guideline on RSV immunoprophylaxis for these children is therefore needed.

Composition of the mucosa-associated microbiota along the entire gastrointestinal tract of human individuals

Background

Homeostasis of the gastrointestinal tract depends on a healthy bacterial microbiota, with alterations in microbiota composition suggested to contribute to diseases. To unravel bacterial contribution to disease pathology, a thorough understanding of the microbiota of the complete gastrointestinal tract is essential. To date, most microbial analyses have either focused on faecal samples, or on the microbial constitution of one gastrointestinal location instead of different locations within one individual.

Objective

We aimed to analyse the mucosal microbiome along the entire gastrointestinal tract within the same individuals.

Methods

Mucosal biopsies were taken from nine different sites in 14 individuals undergoing antegrade and subsequent retrograde double-balloon enteroscopy. The bacterial composition was characterised using 16 S rRNA sequencing with Illumina Miseq.

Results

At double-balloon enteroscopy, one individual had a caecal adenocarcinoma and one individual had Peutz-Jeghers polyps. The composition of the microbiota distinctively changed along the gastrointestinal tract with larger bacterial load, diversity and abundance of Firmicutes and Bacteroidetes in the lower gastrointestinal tract than the upper gastrointestinal tract, which was predominated by Proteobacteria and Firmicutes.

Conclusions

We show that gastrointestinal location is a larger determinant of mucosal microbial diversity than inter-person differences. These data provide a baseline for further studies investigating gastrointestinal microbiota-related disease.

A Rare Case of Laryngopyocele with Airway Obstruction

Laryngocele is a rare entity and can be defined as an abnormal cystic dilatation of saccule of the laryngeal ventricle with communication to the lumen of larynx. Laryngopyocele is a rare complication of laryngocele when it is infected. Patients may present with fever, neck swelling, shortness of breath, and hoarseness. Acute presentation can develop rapidly with alarming symptom, such as stridor, which signifies airway obstruction and warrants immediate treatment and airway protection. Computed tomography and endoscopy are useful in making the diagnosis and delineate the severity of disease. Laryngopyocele should be treated with antibiotics, drainage of purulent content, and followed by definitive surgical excision.

The gastrointestinal microbiota and its role in oncogenesis

Advances in research techniques have made it possible to map the microbial communities in the gastrointestinal (GI) tract, where the majority of bacteria in the human body reside. Disturbances in these communities are referred to as dysbiosis and have been associated with GI cancers. Although dysbiosis is observed in several GI malignancies, the specific role of these changes has not been understood to the extent of Helicobacter pylori (HP) in gastric cancer (GC). This review will address the bacterial communities along the GI tract, from the oral cavity to the anal canal, particularly focusing on bacterial dysbiosis and carcinogenesis. Just as non-HP bacteria in the stomach may interact with HP in gastric carcinogenesis, the same may hold true for other GI tract malignancies, where an interplay between microbes in carcinogenesis seems conceivable, especially in colorectal cancer (CRC). In the last part of this review we will discuss the potential mechanisms of bacterial dysbiosis in GI carcinogenesis.

Visual working memory deterioration preceding relapse in psychosis

BACKGROUND

Relapse is distressingly common after the first episode of psychosis, yet it is poorly understood and difficult to predict. Investigating changes in cognitive function preceding relapse may provide new insights into the underlying mechanism of relapse in psychosis. We hypothesized that relapse in fully remitted first-episode psychosis patients was preceded by working memory deterioration.

METHOD

Visual memory and verbal working memory were monitored prospectively in a 1-year randomized controlled trial of remitted first-episode psychosis patients assigned to medication continuation (quetiapine 400 mg/day) or discontinuation (placebo). Relapse (recurrence of positive symptoms of psychosis), visual (Visual Patterns Test) and verbal (Letter-Number span test) working memory and stressful life events were assessed monthly.

RESULTS

Remitted first-episode patients (n = 102) participated in the study. Relapsers (n = 53) and non-relapsers (n = 49) had similar baseline demographic and clinical profiles. Logistic regression analyses indicated relapse was associated with visual working memory deterioration 2 months before relapse [odds ratio (OR) 3.07, 95% confidence interval (CI) 1.19-7.92, P = 0.02], more stressful life events 1 month before relapse (OR 2.11, 95% CI 1.20-3.72, P = 0.01) and medication discontinuation (OR 5.52, 95% CI 2.08-14.62, P = 0.001).

CONCLUSIONS

Visual working memory deterioration beginning 2 months before relapse in remitted first-episode psychosis patients (not baseline predictor) may reflect early brain dysfunction that heralds a psychotic relapse. The deterioration was found to be unrelated to a worsening of psychotic symptoms preceding relapse. Testable predictors offer insight into the brain processes underlying relapse in psychosis.

Unexplained childhood anaemia: idiopathic pulmonary hemosiderosis

This report demonstrates pulmonary haemorrhage as a differential cause of anaemia. Idiopathic pulmonary hemosiderosis is a rare disease in children; it is classically described as a triad of haemoptysis, pulmonary infiltrates on chest radiograph, and iron-deficiency anaemia. However, anaemia may be the only presenting feature of idiopathic pulmonary hemosiderosis in children due to occult pulmonary haemorrhage. In addition, the serum ferritin is falsely high in idiopathic pulmonary hemosiderosis which increases the diagnostic difficulty. We recommend that pulmonary haemorrhage be suspected in any child presenting with iron-deficiency anaemia and persistent bilateral pulmonary infiltrates.

Upregulation of pituitary adenylate cyclase activating polypeptide and its receptor expression in the rat carotid body in chronic and intermittent hypoxia

The carotid body (CB) plays important roles in cardiorespiratory changes in chronic and intermittent hypoxia. Pituitary adenylate cyclase activating polypeptide (PACAP) is involved in the regulation of respiratory chemoresponse. We hypothesized an upregulation of the expressions of PACAP and its receptor (PAC1) in the rat CB in chronic and intermittent hypoxia. The CB expressions of PACAP and PAC1 were examined in rats breathing 10% O(2) (in isobaric chamber for chronic hypoxia, 24 h/day) or in intermittent hypoxia (cyclic between air and 5% O(2) per minute, 8 h/day) for 7 days. Immunohistochemical studies showed that the PACAP and PAC1 proteins were localized in CB glomic clusters containing tyrosine hydroxylase. The proportional amount of cells with positive staining of PACAP and PAC1 was significantly increased in both hypoxic groups when compared with the normoxic control. In addition, the mRNA level of PAC1 expression was markedly elevated in the hypoxic groups, despite no changes in the PACAP expression. These results suggest an upregulation of PACAP and its receptor expression in the rat CB under chronic and intermittent hypoxic conditions. The PACAP binding to its receptor could activate the PKA signaling pathway leading to an increased CB excitability under hypoxic conditions.

Combined treatment with a dipeptidyl peptidase-IV inhibitor (sitagliptin) and an angiotensin II type 1 receptor blocker (losartan) promotes islet regeneration via enhanced differentiation of pancreatic progenitor cells

AIM

The existence of pancreatic progenitor cells (PPCs) with differentiation capacity in the adult pancreas has rendered that promotion of islet regeneration is feasible. The dipeptidyl peptidase-IV inhibitor sitagliptin and the angiotensin II type 1 receptor (AT(1) receptor) blocker losartan have a common target action in the pancreata. Thus, we evaluated the synergistic/additive effects of these two drugs on the differentiation of islet progenitors.

METHODS

The acute and chronic effects of sitagliptin and losartan, individually or in combination, on islet regeneration in vivo were investigated by using a streptozotocin-induced type 1 diabetes mouse model. Their effects were also examined on an in vitro PPCs model derived from human foetal pancreas.

RESULTS

A chronic combination treatment enhanced glucose tolerance in diabetic mice associated with an increased ratio of β cells to islet; an acute combination treatment resulted in a marked increase in the production of neurogenin 3 (NGN3(+)) cells in proximity to CK7(+) ductal cell and an increased presence of insulin(+) /CK7(+) cells. The in vitro study revealed that a combination treatment significantly enhanced mRNA expression of NGN3, NKX6.1 and PDX-1 during PPCs differentiation into human islet-like cell clusters (ICCs). Despite no apparent changes in insulin release, the combined treatment resulted in increasing production of peroxisome proliferator-activated receptor γ (PPARγ) during PPC differentiation.

CONCLUSIONS

These data indicate that combined sitagliptin-losartan treatment can improve islet function by promoting the differentiation of PPCs into ICCs, perhaps via a mechanism involving PPARγ production, and could thereby, contribute to islet regeneration.

Early detection of central airway lung cancer in smokers with silicosis

BACKGROUND

Smokers with silicosis are at increased risk of lung cancer.

OBJECTIVE

To evaluate the feasibility of using autofluorescence bronchoscopy after sputum examination for early detection of large airway lung cancer and factors associated with the presence of cancerous and pre-cancerous lesions among smokers with silicosis.

METHODS

Subjects at the pneumoconiosis clinic were recruited if they fulfilled the following criteria: 1) age ≥40 years, 2) smoking history of ≥20 pack-years and 3) confirmed diagnosis of silicosis. Sputum specimens were collected for cytology/cytometry examination and autofluorescence bronchoscopy was performed in subjects with an abnormal sputum result.

RESULTS

A total of 48 subjects were recruited during the study period. The mean age and smoking history were respectively 63 ± 10 years and 51 ± 30 pack-years. Intraepithelial lung cancers and pre-neoplastic lesions (squamous metaplasia or above) were detected in respectively 2 (4.2%) and 14 (29.2%) subjects. The proportions of current smokers (75.0% vs. 40.6%, P = 0.03) and asbestos exposure (37.5% vs. 9.4%, P = 0.04) were significantly higher in subjects with the above lesions compared with those without.

CONCLUSIONS

Sputum examination followed by autofluorescence bronchoscopy may be a useful way of identifying cancerous/pre-cancerous lesions among silicotic smokers. Current smoking and asbestos exposure were associated with these lesions.

Epidermal inclusion cyst of the breast: a rare benign entity

Epidermal inclusion cyst (EIC) arising from the breast is an uncommon benign condition. We report two cases of enlarging EIC of the breast in two women in their forties. The diagnosis of this condition may not be straightforward with imaging alone if an EIC presents as an enlarging lump in the breast and mimics a benign breast lesion, most commonly a fibroadenoma or malignant lesion with benign imaging features. Excision is usually recommended for a definite histopathological diagnosis and for the prevention of potential risks of malignant transformation. Asymptomatic stable lesions do not require treatment; biopsy is unnecessary, and follow-up imaging suffices if typical sonographic and clinical findings are found.

The first novel influenza A (H1N1) fatality despite antiviral treatment and extracorporeal membrane oxygenation in Hong Kong

We report the first fatality caused by novel influenza A (H1N1) infection despite having the diagnosis confirmed and being given antiviral treatment after hospitalisation. This patient was also the first with influenza A (H1N1) to be supported with extracorporeal membrane oxygenation in Hong Kong. Although extracorporeal membrane oxygenation is an effective means of supporting patients with refractory hypoxaemia on high mechanical ventilatory support, it is labour-intensive and technically demanding. We also discuss the challenges faced when managing this case.

A comparison between low-dose and standard-dose non-contrasted multidetector CT scanning of the paranasal sinuses

PURPOSE

To compare the image quality of the low-dose to the standard-dose protocol of MDCT scanning of the paranasal sinuses, based on subjective assessment and determine the radiation doses to the eyes and thyroid gland and dose reduction between these two protocols.

MATERIALS AND METHODS

31 adult patients were scanned. Prior to scanning, thermoluminescent dosimeters (TLDs) were placed at 4 sites: outer canthus of right eye, outer canthus of left eye, inner canthus and anterior neck (thyroid gland). Every patient was scanned twice using the standard-dose protocol (100mAs) followed by the low-dose protocol (40mAs). The images were reviewed by 3 radiologists. Wilcoxon test was used as the test of significance for the image quality assessments. The paired sample t-test was used as the test of significance for the analysis of the radiation doses measured by the TLDs.

RESULTS

Of the 30 patients selected for analysis, this study showed no significant difference in the scores for the diagnostic image quality and the anatomical structures assessments between the two protocols. The average calculated mean entrance surface doses and standard deviation for the standard-dose and low-dose protocols were 12.40±1.39 mGy and 5.53±0.82 mGy respectively to the lens and 1.03±0.55 mGy and 0.63±0.53 mGy respectively to the thyroid gland.

CONCLUSION

The reduction of mAs from 100 to 40 resulted in a significant reduction of the radiation doses to the lens and thyroid gland by 55.4% and 38.8% respectively without causing any significant effect to the diagnostic image quality and assessment of the anatomical structures.

Upregulation of erythropoietin and its receptor expression in the rat carotid body during chronic and intermittent hypoxia

The carotid body (CB) plays important roles in cardiorespiratory changes in intermittent hypoxia (IH). Erythropoietin (EPO), a hypoxia-inducible factor (HIF)-1 target gene, is present in the chemoreceptive type-I cells in the CB but its expression and role in IH resembling sleep apnoeic conditions are not known. We hypothesized that IH upregulates the expression of EPO and its receptor (EPOr) in the rat CB. The CB expressions of EPO and EPOr were examined in rats breathing 10% O(2) (in isobaric chamber for CH, 24 hour/day) or in IH (cyclic between air and 5% O(2) per minute, 8 hour/day) for 3-28 days. Immunohistochemical studies revealed that the EPO and EPOr proteins were localized in CB glomic clusters. The proportional amount of cells with positive staining of EPO immunoreactivities was significantly increased in both IH and CH groups when compared with the normoxic control. The EPO expression was more markedly increased in the CH than that of the IH groups throughout the time course, reaching a peak level at day 14. The positive EPOr immunostaining was increased significantly in the 3-day CH group. By day 14, the EPOr expression elevated considerably at peak levels in both IH and CH rats, whereas the elevation was greater in the CH rats. These results suggest an upregulation of EPO and its receptor expression in the rat CB under IH and CH conditions, presumably mediated by the activation of HIF-1 pathway. The increased EPO binding to its receptor might play a role in the enhancement of CB excitability during the early pathogenesis in patients with sleep-disordered breathing.

Use of antibody avidity assays for diagnosis of severe acute respiratory syndrome coronavirus infection

An indirect immunofluorescent assay (Euroimmun AG, Luebeck, Germany) was used to investigate the avidity of immunoglobulin G (IgG), IgM, IgA, and total Ig (IgGAM) antibody responses to severe acute respiratory syndrome coronavirus (SARS CoV) infections. Serial serum samples from eight patients collected during the first, third, and ninth months after the onset of infection were evaluated. It was found that low-avidity IgG antibodies were detected in 15/15 (100%), 1/5 (20%), and 0/8 (0%) serum samples collected during the first, third, and ninth months after the onset of symptoms, respectively. Low-avidity antibodies of IgA and IgM subclasses were detected in 14/14 (100%) and 3/14 (21%) serum samples, respectively, collected in the first month after the onset of infection. However, IgA antibodies remained low in avidity in a proportion of patients even during late convalescence. As a consequence, IgG antibody avidity assays gave better discrimination between acute-phase and late-convalescent-phase serum samples than IgM, IgA, or IgGAM assays. In two of these patients, sequential serum samples were also tested for IgG avidity against human CoV strains OC43 and 229E in parallel. While SARS CoV infections induced an anamnestic IgG antibody response to the 229E and OC43 viruses, these cross-reactive antibodies remained of high avidity from early (the first month) postinfection. The results showed that assays to detect low-avidity antibody may be useful for discriminating early from late antibody responses and also for distinguishing anamnestic cross-reactive antibody responses from primary specific responses. This may be useful in some clinical situations.

Comparative analytical sensitivities of six rapid influenza A antigen detection test kits for detection of influenza A subtypes H1N1, H3N2 and H5N1

BACKGROUND

Rapid and simple methods for diagnosing human influenza A (H5N1) disease urgently needed. The limited data so far suggest that the currently available rapid antigen detection kits have poor clinical sensitivity for diagnosis of human H5N1 disease.

OBJECTIVES

To compare the analytical sensitivity of six commercially available rapid antigen detection kits for the detection of "human" (subtypes H1N1, H3N2) and "avian" (subtype H5N1) influenza A viruses.

STUDY DESIGN

Six commercially available test kits for the detection of influenza A were investigated. Analytic sensitivity for the detection of two contemporary H1N1, two H3N2 and three H5N1 viruses was determined using virus culture as a reference method.

RESULTS AND CONCLUSIONS

Each test kit detected the H5N1 virus subtypes as efficiently as they detected conventional human viruses of subtypes H1N1 or H3N2. However, limits of detection of influenza viruses of all subtypes by antigen detection kits were >1000-fold lower than virus isolation. Thus, the reportedly poor clinical sensitivity of these antigen detection kits for diagnosis of patients with H5N1 disease is not due to a difference of sensitivity for detecting avian influenza H5N1 compared to human influenza viruses.

Merosin-deficient congenital muscular dystrophy in two siblings

Congenital muscular dystrophies are a group of heterogeneous inherited autosomal recessive disorders. The so-called 'pure' or 'occidental' form is further divided into merosin-positive and merosin-negative subgroups. Merosin is also expressed in the nervous system and its deficiency could affect development of the nervous system. The authors report two siblings with merosin-negative congenital muscular dystrophy. The clinical picture, biopsy findings, and abnormalities as detected by the magnetic resonance imaging of the two patients are presented.

HAb18G/CD147-mediated calcium mobilization and hepatoma metastasis require both C-terminal and N-terminal domains

HAb18G/CD147 is a heavily glycosylated protein containing two immunoglobulin superfamily domains. Our previous studies have indicated that overexpression of HAb18G/CD147 enhances metastatic potentials in human hepatoma cells by disrupting the regulation of store-operated Ca2+ entry by nitric oxide (NO)/cGMP. In the present study, we investigated the structure-function of HAb18G/CD147 by transfecting truncated HAb18G/CD147 fragments into human 7721 hepatoma cells. The inhibitory effect of HAb18G/CD147 on 8-bromo-cGMP-regulated thapsigargin-induced Ca2+ entry was reversed by the expression of either C or N terminus truncated HAb18G/CD147 in T7721deltaC and T7721deltaN cells, respectively. The potential effect of HAb18G/CD147 on metastatic potentials, both adhesion and invasion capacities, of hepatoma cells was abolished in T7721deltaC cells, but not affected in T7721deltaN cells. Release and activation of matrix metalloproteinases (MMPs), MMP-2 and MMP-9, were found to be enhanced by the expression of HAb18G/CD147, and this effect was abolished by both truncations. Thapsigargin significantly enhanced release and activation of MMPs (MMP-2 and MMP-9) in non-transfected 7721 cells, and this effect was negatively regulated by SNAP. However, no effects of thapsigargin or SNAP were observed in T7721 cells, and expression of HAb18G/CD147 enhanced secretion and activation of MMPs at a stable and high level. Taken together, these results suggest that both ectodomain and intracellular domains of HAb18G/CD147 are required to mediate the effect of HAb18G/CD147 on the secretion and activation of MMPs and metastasis-related processes in human hepatoma cells by disrupting the regulation of NO/cGMP-sensitive intracellular Ca2+ mobilization although each domain may play different roles.

Features predicting adverse outcomes of status epilepticus in childhood

OBJECTIVE

To examine variables that might predict abnormal outcome of status epilepticus among children.

DESIGN

Retrospective study.

SETTING

Regional hospital, Hong Kong.

PATIENTS

All children younger than 15 years who were admitted to the paediatric intensive care unit with status epilepticus between 1997 and 2002.

MAIN OUTCOME MEASURES

Neurodevelopmental outcomes.

RESULTS

Two of the 25 patients died, resulting in a mortality rate of 8%. No deaths were due to status epilepticus itself. No patient with febrile or idiopathic status epilepticus developed epilepsy. Neurological deterioration was observed in a quarter (six of 23) of the survivors. Symptomatic aetiology (acute or remote) and refractory status epilepticus were associated with adverse outcomes (P<0.05). Young age at status epilepticus (<12 months) and duration of status epilepticus (>60 minutes) tended to be more frequent among those who developed adverse outcome. Rectal diazepam was given before hospital arrival in only four patients.

CONCLUSIONS

Paediatric patients with status epilepticus who had normal neurodevelopmental status before the onset of an attack and who did not sustain an acute insult to the central nervous system or have progressive encephalopathy, had favourable outcomes. Prompt use of rectal diazepam or buccal midazolam administered by caretakers or paramedics should be encouraged.

Expression, immunolocalization, and functional activity of Na+/H+ exchanger isoforms in mouse endometrial epithelium

The luminal fluid microenvironment of the uterus is important for sperm capacitation and embryo development. In an attempt to understand the possible role of Na(+)/H(+) exchangers (NHEs) in uterine function, the mRNAs of different NHE isoforms as well as their subcellular localization (apical versus basolateral) and functional activity were investigated in mouse endometrial epithelial cells using reverse transcriptase-polymerase chain reaction (RT-PCR), immunohistochemistry, and intracellular pH (pH(i)) measurement techniques. The presence of NHE1, NHE2, and NHE4, but not NHE3 mRNAs were revealed by RT-PCR. Immunostaining showed that NHE1, NHE2, and NHE4 were present in both apical and basolateral membranes. The pH(i) recovery from intracellular acidification was Na(+)-dependent; however, the rate of pH(i) recovery depending on basolateral Na(+) was 12.4 times faster than that depending on apical Na(+). The Na(+)-dependent rate of pH(i) recovery was also inhibited by amiloride, indicating H(+) extrusion through NHEs; however, the amiloride sensitivity of the apical membrane was less than that of the basolateral membrane, suggesting the involvement of different types of NHEs in the two membranes. The results indicate that the basolaterally located NHE1, NHE2, and NHE4, in addition to participating in the homeostatic control of intracellular pH, may play a role in H(+) extrusion in order to achieve transepithelial HCO(3)(-) secretion. The apically located NHEs may be involved in mediating Na(+) absorption as alternatives of or complementary to epithelial Na(+) channels.

Non-accidental carbon monoxide poisoning from burning charcoal in attempted combined homicide-suicide

OBJECTIVE

To describe an emerging form of serious child abuse in combined homicide-suicide in Hong Kong.

METHOD

This is a retrospective hospital chart review in a regional hospital in Hong Kong from January to December 2000.

RESULTS

Eight children, with a mean age of 7.8 years (range 0.5-11 years), from four families were admitted to hospital because of non-accidental exposure to carbon monoxide when their parents attempted suicide by burning charcoal. A 7-year-old boy died on arrival. His 5.6-year-old sister and another 6-month-old boy had cerebral hypoxia on admission. Hyperbaric oxygen therapy was used in both cases, with rapid improvement, although there were persistent neurological deficits in the girl. The other children in the present study were asymptomatic and none had delayed neurological sequelae. Concomitant use of sedatives was also detected in three of the surviving patients.

CONCLUSIONS

Non-accidental poisoning with carbon monoxide appears to be a new means of child abuse with potentially serious consequences. Concomitant intoxication with psychotropic drugs is common in such cases. The reason for parents killing their own children under such circumstances was unclear, but a desire to exact revenge on an estranged partner was suggested.

Postnatal hypoxemia increases angiotensin II sensitivity and up-regulates AT1a angiotensin receptors in rat carotid body chemoreceptors

In the present study, the effects of postnatal hypoxemia on the AT1 angiotensin receptor-mediated activities in the rat carotid body were studied. Angiotensin II (Ang II) concentration-dependently increased the chemoreceptor afferent activity in the isolated carotid body. Single- or pauci-fiber recording of the sinus nerve revealed that the afferent response to Ang II was enhanced in the postnatally hypoxic carotid body. To determine whether the increased sensitivity to Ang II is mediated by changes in the functional expression of Ang II receptors in the carotid body chemoreceptors, cytosolic calcium ([Ca2+]i) was measured by spectrofluorimetry in fura-2 acetoxymethyl ester-loaded type I cells dissociated from carotid bodies. Ang II (25-100 nM) concentration-dependently increased [Ca2+]i in the type I cells. The proportion of clusters of type I cells responsive to Ang II was higher in the postnatally hypoxic group than in the normoxic control (89 vs 66%). In addition, the peak [Ca2+]i response to Ang II was enhanced 2- to 3-fold in the postnatally hypoxic group. The [Ca2+]i response to Ang II was abolished by pretreatment with losartan (1 microM), an AT1 receptor antagonist, but not by PD-123177 (1 microM), an AT(2) antagonist. Double-labeling immunohistochemistry confirmed that an enhanced immunoreactivity for AT1 receptor was co-localized to the lobules of type I cells in the hypoxic group. In addition, RT-PCR analysis of subtypes of AT1 receptors showed an up-regulation of AT1a but a down-regulation of AT1b receptors, indicating a differential regulation of the expression of AT1 receptor subtypes by postnatal hypoxia in the carotid body. These data suggest that postnatal hypoxemia is associated with an increased sensitivity of peripheral chemoreceptors in response to Ang II and an up-regulation of AT1a receptor-mediated [Ca2+]i activity of the chemoreceptors. This modulation may be important for adaptation of carotid body functions in the hypoxic ventilatory response and in electrolyte and water homeostasis during perinatal and postnatal hypoxia.

Life threatening acute epiglottitis in acute leukemia

We report an 8-year-old boy who developed a life-threatening acute epiglottitis during induction chemotherapy for acute promyelocytic leukemia. He survived the infection with emergency tracheostomy, treatment with broad spectrum antibiotics and amphotericin, and the use of granulocyte-macrophage colony stimulating factor. No organism was identified. A literature review identified 18 cases of acute epiglottitis in cancer patients. Sixteen of them were suffering from hematologic malignancies and three patients had received bone marrow transplantation. Unlike the usual case of epiglottitis, the majority (15 out of 18) of affected patients were adults and none of the infections was associated with Haemophilus influenzae. Streptococcus pneumoniae and Candida albicans were the most frequently identified pathogens. Early recognition and aggressive supportive care are required for successful management.

Local regulation of anion secretion by pituitary adenylate cyclase-activating polypeptide in human colonic T84 cells

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a novel hypothalamic peptide, which has been shown to exert various functions in a number of tissues, including exocrine and endocrine tissues. The present study investigated the role of local PACAP in the control of anion secretion by the human colonic T84 cell. Both bioactive forms of PACAP-27 and PACAP-38 gave rise to a dose-dependent increase in the short-circuit current (I(SC)). However, there was a reversal in the order of potency observed at different concentration ranges for the two bioactive forms. PACAP-27 was greater than PACAP-38 when the peptide concentrations were below 10 n m; PACAP-38 was greater than PACAP-27 in the range of 10-80 n m. The effects of both PACAP forms were restricted to the apical aspect of the T84 cell. The I(SC)responses to both PACAP-27 and PACAP-38 were suppressed respectively by the non-selective Cl(-)channel blocker, diphenylamine-dicarboxylic acid (DPC), by the Ca(2+)dependent Cl(-)channel blocker, diisothiocyanatostilbene-disulfonic acid (DIDS) and by the Ca(2+)chelator, BAPTA-AM, indicating the involvement of Ca(2+). The expression of PACAP was demonstrated and localized specifically to the perinuclear cytoplasm of the T84 cell using immunocytochemistry, indicating its epithelial origin. Thus, the present data suggest that, in addition to the well-known cAMP-dependent pathway, PACAP may play a role in regulating colonic Cl(-)secretion via a Ca(2+)-dependent pathway, perhaps through two distinct PACAP receptor subtypes. Moreover, the regulation of anion secretion by T84 cells may be mediated by locally formed PACAP in an autocrine or paracrine fashion.

Functional expression of angiotensin II receptors in type-I cells of the rat carotid body

Angiotensin II increases afferent discharge from the carotid body in vitro. We hypothesized that angiotensin II receptors (AT receptors) are expressed functionally in the type-I cell of the carotid body. Cytosolic free [Ca2+] ([Ca2+]i) in type-I cells freshly dissociated from rat carotid bodies was measured spectrofluorimetrically. Angiotensin II (10-100 nM) concentration-dependently increased [Ca2+]i in type-I cells. The [Ca2+]i response was blocked by pretreatment with losartan (1 microM), an AT1 receptor antagonist, but not by blockade of AT2 receptors with PD- 123319 (1 microM). Moreover, the gene expression of AT1 receptors was assessed by the reverse transcriptase polymerase chain reaction and gene transcripts of both AT1a and AT1b receptors were detected in the carotid body. In addition, immunohistochemical study revealed that AT1 immunoreactivity was localized in lobules of type-I cells in the carotid body. Taken together, these results suggest that type-I cells in the rat carotid body express functional angiotensin II receptors. The binding of angiotensin II to the AT1 receptors increases [Ca2+]i, a key step of the intracellular signalling cascade following the activation of the receptors. It is concluded that angiotensin II modulates carotid body chemoreceptor function directly via AT1 receptors in the type-I cell.

Chronic hypoxia upregulates the expression and function of AT(1) receptor in rat carotid body

In the present study, the effects of chronic hypoxia on the expression and localization of angiotensin II (Ang II) receptors are investigated by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and by immunohistochemistry. The effect of chronic hypoxia on the carotid body chemoreceptor activity was also examined by in vitro electrophysiology. Results from RT-PCR revealed that chronic hypoxia exhibited differential effects on the gene expression of Ang II receptors, namely AT(1) and AT(2), in the carotid body. The mRNA expression for subtypes of the AT(1) receptor, AT(1a) and AT(1b), was significantly increased in the carotid body with chronic hypoxia. To further investigate the localization of the AT(1) receptor, an immunohistochemical study was performed. The results showed that AT(1) receptor immunoreactivity was found in lobules of glomus cells in the carotid body and the immunoreactivity was more intense in chronic hypoxia than in normoxic controls. In vitro electrophysiological studies consistently demonstrated that chronic hypoxia enhanced the AT(1) receptor-mediated excitation of carotid body chemoreceptor activity. These data suggest that chronic hypoxia upregulates the transcriptional and post-transcriptional expression of AT(1) receptors in the rat carotid body. The upregulation of the expression also enhances AT(1) receptor-mediated excitation of the carotid body afferent activity. This might be important in the modulation of cardiorespiratory functions as well as fluid and electrolyte homeostasis during chronic hypoxia.

Testicular hormonal regulation of the renin-angiotensin system in the rat epididymis

Evidence for the existence of an intrinsic angiotensin system based on locally formed angiotensinogen as a precursor for angiotensin production has been demonstrated in the rat epididymis. The data strongly support the presence of an epididymal renin-angiotensin system (RAS) which may be important for epididymal and sperm functions. In the present study, the effects of castration and testicular hormonal replacement on the expression of RAS components from the rat epididymis are investigated at the gene and protein levels. Results from northern blot and western blot analyses consistently showed that the expression of angiotensinogen mRNA and protein was apparently abolished by castration whereas their expression was completely restored to control levels when the castrated rats were hormonally replaced with either testosterone alone or with combined testosterone and estradiol. Northern blot did not detect any signal for angiotensinogen mRNA while western blot could detect a weak signal for angiotensinogen protein when the castrated rats were replaced with estradiol alone. Renin could be detected neither in control, castrated nor hormonally replaced rats. Moreover, the expression of angiotensin II receptor, type I (AT1) was almost abolished by castration as demonstrated by northern blot and reverse transcription-polymerase chain reaction. These data indicate that the expression of RAS by the rat epididymis at the levels of its precursor angiotensinogen and its receptor AT1, is subject to the regulation of testicular hormones and its expression appears to be predominantly testosterone-dependent.

Ammonia clearance by peritoneal dialysis and continuous arteriovenous hemodiafiltration

We report the use of continuous arteriovenous hemodiafiltration (CAVHD) in a neonate with severe hyperammonemia due to a urea cycle disorder. We compared the ammonia clearance (C(NH3)) for peritoneal dialysis (PD) and CAVHD. C(NH3) for CAVHD was 7.45 ml/min per m2 at a dialysate flow of 300 ml/h and was 10.55 ml/min per m2 at a dialysate flow rate of 600 ml/h. The mean PD clearance was 2.15 ml/min per m2. Our data suggest that CAVHD is superior to PD for the removal of plasma ammonia. We conclude that CAVHD should be considered a reasonable alternative in the treatment of neonatal hyperammonemia in urea cycle disorders when medical treatment fails.

Concurrent and independent HCO3- and Cl- secretion in a human pancreatic duct cell line (CAPAN-1)

The present study investigated both HCO-3 and Cl- secretions in a human pancreatic duct cell line, CAPAN-1, using the short-circuit current (Isc) technique. In Cl-/HCO-3-containing solution, secretin (1 microM) or forskolin (10 microM) stimulated a biphasic rise in the Isc which initially reached a peak level at about 3 min and then decayed to a plateau level after 7 min. Removal of external Cl- abolished the initial transient phase in the forskolin-induced Isc while the plateau remained. In HCO-3/CO2-free solution, on the contrary, only the initial transient increase in Isc was prominent. Summation of the current magnitudes observed in Cl--free and HCO-3-free solutions over a time course of 10 min gave rise to a curve which was similar, both in magnitude and kinetics, to the current observed in Cl-/HCO-3-containing solution. Removal of external Na+ greatly reduced the initial transient rise in the forskolin-induced Isc response, and the plateau level observed under this condition was similar to that obtained in Cl--free solution, suggesting that Cl--dependent Isc was also Na+-dependent. Bumetanide (50 microM), an inhibitor of the Na+-K+-2Cl- cotransporter, and Ba2+ (1 mm), a K+ channel blocker, could reduce the forskolin-induced Isc obtained in Cl-/HCO-3-containing or HCO-3-free solution. However, they were found to be ineffective when external Cl- was removed, indicating the involvement of these mechanisms in Cl- secretion. On the contrary, the HCO-3-dependent (in the absence of external Cl-) forskolin-induced Isc could be significantly reduced by carbonic anhydrase inhibitor, acetazolamide (45 microM). Basolateral application of amiloride (100 microM) inhibited the Isc; however, a specific Na+-H+ exchanger blocker, 5-N-methyl-N-isobutylamiloride (MIA, 5-10 microM) was found to be ineffective, excluding the involvement of the Na+-H+ exchanger. However, an inhibitor of H+-ATPase, N-ethylmaleimide did suppress the Isc (IC50 = 22 microM). Immunohistochemical studies also confirmed the presence of a vacuolar type of H+-ATPase in these cells. H2DIDS (100 microM), an inhibitor of Na+-HCO-3 cotransporter, was without effect. Apical addition of Cl- channel blocker, diphenylamine-2,2'-dicarboxylic acid (DPC, 1 mm), but not disulfonic acids, DIDS (100 microM) or SITS (100 microM), exerted an inhibitory effect on both Cl- and HCO-3-dependent forskolin-induced Isc responses. Histochemical studies showed discrete stainings of carbonic anhydrase in the monolayer of CAPAN-1 cells, suggesting that HCO-3 secretion may be specialized to a certain population of cells. The present results suggest that both HCO-3 and Cl- secretion by the human pancreatic duct cells may occur concurrently and independently.

Nodular histiocytic/mesothelial hyperplasia: a lesion potentially mistaken for a neoplasm in transbronchial biopsy

This report describes two examples of nodular histiocytic/ mesothelial hyperplasia as seen in transbronchial biopsy that initially led to serious consideration of neuroendocrine neoplasm or meningioma. The biopsies showed nodular collections of cohesive polygonal or round cells with ovoid or deeply grooved nuclei and a moderate amount of finely granular cytoplasm. Nuclear pleomorphism was mild. Immunohistochemical studies showed few cells staining for cytokeratin and the mesothelial marker HBME-1, whereas most cells were decorated by the histiocytic marker PG-M1 (CD68). This lesion appears to be identical to nodular mesothelial hyperplasia as described in hernia sacs and mesothelial/monocytic incidental cardiac excrescences, and we propose modifying the designation to "nodular histiocytic/mesothelial hyperplasia" to take into account the marked predominance of histiocytes over mesothelial cells. The clues to recognition of the true nature of the lesion are clinicopathologic correlation and identification of strips of low cuboidal (mesothelial) cells in the vicinity, and the diagnosis can be further confirmed by immunohistochemical staining. Nodular histiocytic/mesothelial hyperplasia probably results from irritation to the mesothelial lining by various causes leading to focal aggregation of histiocytes within retraction pockets or crevices of the serosal cavity.

Evaluation of a histogenetic classification for thymic epithelial tumours

We reviewed 87 thymic epithelial tumours from Chinese patients and typed them according to the Marino and Müller-Hermelink classification as updated by Kirschner and Müller-Hermelink in 1989. Related categories were grouped for statistical analyses: group 1, medullary thymoma and mixed thymoma; group 2, cortical predominant thymoma; group 3, cortical thymoma and well-differentiated thymic carcinoma; group 4, other thymic carcinomas; and group 5, unclassified. Group 3 tumours were more frequently associated with the myasthenia gravis syndrome compared with group 1 tumours (P = 0.001). They also presented at a more advanced stage. Groups 1 and 2 showed an excellent prognosis (100% survival at 10 years). The 10-year survival for groups 3 and 4 patients was 40% and 30% respectively. Pure medullary thymoma made up a higher proportion of our cases (10.3%) than those of a similar Caucasian study (5.3%). The eight thymic carcinomas (group 4) included two thymic lymphoepitheliomas. We conclude that the histogenetic classification evaluated shows a clear correlation with prognosis and clinical features, even when tested on separate geographic groups, where pathogenetic factors may be different. A common approach to classification of thymic epithelial tumours would greatly facilitate future studies on these possible differences.

Hepatitis C virus antibody in multiply transfused Chinese with thalassaemia major

Thirty-four of 99 multiply transfused Chinese (49 females, 50 males) with thalassaemia major were positive for antibody to hepatitis C virus. There was no sex predominance in seropositivity with 18 females and 16 males positive. The mean (+/- SD) age and units of blood transfused were significantly higher in the seropositive patients (167 +/- 48 months, 206 +/- 82 units respectively) than the seronegative patients (113 +/- 56 months, 124 +/- 80 units respectively). The seropositive patients had higher mean (+/- SD) serum alanine aminotransferase, aspartate aminotransferase and ferritin concentrations (91 +/- 82 IU/L, 67 +/- 38 IU/L, 4797 +/- 2522 ng/ml respectively) than the seronegative patients (38 +/- 29 IU/L, 48 +/- 28 IU/L, 3620 +/- 2140 ng/ml respectively). Serum ferritin had an independent and significant effect on serum alanine aminotransferase in addition to that of seropositivity to hepatitis C virus.

Factors affecting fetal loss in induction of ovulation with gonadotropins: increased abortion rates related to hormonal profiles in conceptual cycles

Thirty-six first-trimester abortions (9.7%), 16 second-trimester abortions (4.3%), 11 ectopic pregnancies (2.9%), and 10 stillbirths (2.7%) occurred in 373 conceptual cycles after gonadotropin induction of ovulation. Fetal wastage was higher in spontaneous pregnancies that occurred before therapy (54.3%, p less than 0.0001) and lower with subsequent spontaneous pregnancies (10.1%, p less than 0.05). Significant risk factors for overall fetal loss during induced ovulation were a continuous rise of estrogen excretion until ovulation (p less than 0.01) and previous abortion (p less than 0.05). For first-trimester abortion, the risk factor was continuous estrogen rise (p less than 0.01); for second-trimester abortion, the risk factors were a low luteal pregnanediol-to-estrogen excretion ratio (p less than 0.002), increased age at conception (p less than 0.02), and high baseline estrogen excretion (p less than 0.05). Multiple pregnancy was not significant. The continuous rising estrogen pattern may serve as a marker of abnormal oocyte maturation. We propose that future studies on infertility treatment should report on pregnancy outcome.

Treatment-independent pregnancies after cessation of gonadotropin ovulation induction in women with oligomenorrhea and anovulatory menses

Life-table analysis was performed for the cumulative spontaneous pregnancy rate (CSPR) of 56 patients with oligomenorrhea and anovulatory cycles who had been treated with gonadotropin for ovulation induction between 1963 and 1985. Twenty-seven had at least one spontaneous pregnancy, giving rise to a CSPR of 66.4% (95% confidence limit [CL] 42.4% to 90.4%) at 115 months for the first spontaneous pregnancy, which is significantly lower than the cumulative induced pregnancy rate (CIPR) of 88.6% at 23 months for the first course of gonadotropin therapy (P less than 0.0001). This fertility potential was not affected by the baseline estrogen and follicle-stimulating hormone levels, diagnosis, result of gonadotropin therapy, and age and menstrual pattern during exposure to spontaneous pregnancy by Cox regression analysis. More multiple births occurred in the induced pregnancies than in the spontaneous pregnancies (P = 0.005).

Outcome of patients with one ovary in an in vitro fertilization program

To determine whether the absence of one ovary would influence adversely the outcome of in vitro fertilization, the results of 60 laparoscopic oocyte retrieval procedures in 34 single-ovary patients were compared with the outcome for all laparoscopic retrieval cycles during the same period (January 1984-August 1986) in patients with tubal infertility and two accessible ovaries (559 cycles in 335 patients). The median age was younger in the one-ovary group (31 vs 32) (P less than 0.05). The group with two accessible ovaries had significantly more follicles aspirated (median, 7 vs 5; P less than 0.001) and more oocytes obtained (median, 5 vs 4; P less than 0.001) per retrieval compared with the single-ovary group. However, the single-ovary group had a higher percentage fertilization (69 vs 62%; P less than 0.05) so that the number of embryos transferred per transfer patient (median, 3 vs 3) and pregnancy rate per cycle (9.7 vs 15.6%) did not differ significantly between groups. We conclude that patients with a single ovary have a compensatory increase in the ability to produce oocytes which may have greater potential for fertilization and subsequent development.

Smoking, passive smoking and histological types in lung cancer in Hong Kong Chinese women

In a case control study in Hong Kong, 445 cases of Chinese female lung cancer patients all confirmed pathologically were compared with 445 Chinese female healthy neighbourhood controls matched for age. The predominant histological type was adenocarcinoma (47.2%). The relative risk (RR) in ever-smokers was 3.81 (P less than 0.001, 95% CI = 2.86, 5.08). The RRs were statistically significantly raised for all major cell types with significant trends between RR and amount of tobacco smoked daily. Among never smoking women, RR for passive smoking due to a smoking husband was 1.65 (P less than 0.01, 95% CI = 1.16, 2.35) with a significant trend between RR and amount smoked daily by the husband. When broken down by cell types, the numbers were substantial only for adenocarcinoma (RR = 2.12, P less than 0.01, 95% CI = 1.32, 3.39) with a significant trend between RR and amount smoked daily by the husband. The results suggest that passive smoking is a risk factor for lung cancer, particularly adenocarcinoma in Hong Kong Chinese women who never smoked.

Mild to moderate abnormalities of semen do not affect pregnancy rates during ovulation induction with gonadotrophins

One or more semen analysis results were available for 195 men whose wives responded to ovulation induction with gonadotrophins performed at The Royal Women's Hospital since 1963. Fifty-three men (27%) has subnormal semen analyses by conventional criteria: sperm concentration less than or equal to 20 X 10(6)/ml, motility less than or equal to 40% or normal morphology less than or equal to 50%. The lifetable pregnancy rates were not significantly different for those with subnormal and normal semen (chi 2 = 0.169), by six cycles 64% (s.e.m. = 7) with subnormal semen had conceived compared with 59% (s.e.m. = 5) with normal semen. It appears that lower limits of semen quality could be relaxed for women needing ovulation induction with gonadotrophins.