Different types of visual cells in the photoreceptor layer of the retinae of the treeshrew (Tupaia belangeri chinensis) as revealed by scanning microscopy.

BACKGROUND: The retinae of treeshrew have never been evaluated by scanning electron microscopic studies. MATERIALS AND METHODS: This work described the visual cells in the photoreceptor layer of the retinae of treeshrew (Tupaia belangeri chinensis) living on the high plateau of Yunnan, China, via scanning electron microscopy. RESULTS: Results indicated five morphologically different types of cones, two of which contain oil droplets in their inner segments. To our knowledge, no prior studies have reported oil droplets in the visual cells of higher mammals, only in lower vertebrate and primitive mammals. In addition, this study revealed one type of degenerative visual cell without outer segments. CONCLUSIONS: The findings signal the needs for additional studies to understand the physiological functions and phylogenetic relationships of the diversity of visual cells in this group of mammal.

Brain death in children: a retrospective review of patients at a paediatric intensive care unit.

PURPOSE: Among patients in paediatric intensive care units (PICUs), death is sometimes inevitable despite advances in treatment. Some PICU patients may have irreversible cessation of all brain function, which is considered as brain death (BD). This study investigated demographic and clinical differences between PICU patients with BD and those with cardiopulmonary death. METHODS: All children who died in the PICU at a university-affiliated trauma centre between October 2002 and October 2018 were included in this retrospective study. Demographics and clinical characteristics were compared between patients with BD and patients with cardiopulmonary death. RESULTS: Of the 2784 patients admitted to the PICU during the study period, 127 died (4.6%). Of these 127 deaths, 22 (17.3%) were BD and 105 were cardiopulmonary death. Length of PICU stay was shorter for patients with cardiopulmonary death than for patients with BD (2 vs 8.5 days, P=0.0042). The most common mechanisms of injury in patients with BD were hypoxic-ischaemic injury (40.9%), central nervous system infection (18.2%), and traumatic brain injury (13.6%). The combined proportion of accident and trauma-related injury was greater in patients with BD than in patients with cardiopulmonary death (27.3% vs 3.8%, P<0.001). Organ donation was approved by the families of four of the 22 patients with BD (18.2%) and was performed successfully in three of these four patients. CONCLUSIONS: These findings emphasise the importance of injury prevention in childhood, as well as the need for education of the public regarding acceptance of BD and support for organ donation.

A novel mitochondrial DNA deletion in a Chinese girl with Kearns-Sayre syndrome.

Kearns-Sayre syndrome is a rare disorder often caused by mitochondrial DNA rearrangement. The most commonly reported mitochondrial DNA deletion is 4977 bp in size spanning nucleotides 8469 and 13447. The clinical signs of Kearns-Sayre syndrome include chronic progressive external ophthalmoplegia, retinitis pigmentosa, heart block and cerebellar ataxia, as well as other heterogeneous manifestations including neuromuscular problems and endocrine disorders. Cardiac conduction defects can develop insidiously, leading to sudden death sometimes if not promptly recognised. This report focuses on the diagnosis of Kearns-Sayre syndrome in a Chinese girl who presented initially with short stature, delayed puberty, insidious onset of ptosis and later with typical features of Kearns-Sayre syndrome including complete heart block. Genetic analysis disclosed a novel 7.2 kilobases deletion in muscle tissue. Mitochondrial diseases have heterogeneous phenotypes and mutational analysis has proven to be an effective tool for confirming the diagnosis.

Sequential non-traumatic femoral shaft fractures in a patient on long-term alendronate.

Fractures associated with osteoporosis are common among elderly people and postmenopausal women. Bisphosphonate is an effective anti-resorptive drug commonly used for the prevention and treatment of osteoporosis. There are, however, concerns about potential side-effects during long-term treatment with alendronate. We report a case where an 82-year-old woman who had been taking alendronate for 10 years presented with two episodes of non-traumatic femoral shaft fracture. An iliac bone biopsy showed severely suppressed bone turnover, suggestive of adynamic bone disease. We suspect the bone turnover suppression was related to the prolonged use of alendronate.

Juvenile-onset glycogen storage disease type II with novel mutations in acid alpha-glucosidase gene.

The authors describe two novel mutations of the acid alpha-glucosidase gene, P361L and R437C, which define the juvenile-onset glycogen storage disease type II (GSDII) in a 16-year-old Chinese patient. The asymptomatic 13-year-old brother of the proband is also a compound heterozygote of the two mutations. These results confirm that intrafamilial phenotypic variation of juvenile-onset GSDII is ethnically diverse and suggest the contribution of other genes to the phenotypic variability of GSDII.

Respiratory insufficiency in a Chinese adult with mitochondrial myopathy.

Mitochondrial myopathy is an important but uncommon cause of respiratory insufficiency in adults. We report the first case of respiratory insufficiency associated with adult-onset mitochondrial myopathy seen in a Chinese adult in Hong Kong. The patient presented with peripheral oedema and shortness of breath over 2 to 3 days. There was a history of gradual progressive limb weakness over approximately 2 years, hypertrophic cardiomyopathy, intermittent diarrhoea, and weight loss. The diagnosis was made by skeletal muscle biopsy and molecular study, which revealed the A3243G point mutation.

Classic late infantile neuronal ceroid lipofuscinosis in a Chinese patient.

Neuronal ceroid lipofuscinoses are a group of rare neurodegenerative disorders that are characterised by an accumulation of autofluorescent lipopigments in neurons and extraneuronal tissues. We report on a 4-year-old boy who presented with an acute onset of seizures followed by rapid psychomotor deterioration, ataxia, and visual failure. Photic stimulation at 1 to 3 Hz elicited discrete spike and wave discharges in the electroencephalogram, which were diminished at a higher frequency of stimulation. The electroretinogram was extinct. Magnetic resonance imaging of the brain showed generalised cerebral and cerebellar atrophy. Electron microscopic examination of lymphocytes and samples of muscle and skin revealed characteristic curvilinear inclusion bodies. To our knowledge, this is the first case of late infantile neuronal ceroid lipofuscinosis to be reported in a Hong Kong Chinese patient.

Classifying the location of osteosarcoma with reference to the epiphyseal plate helps determine the optimal skeletal resection in limb salvage procedures.

Between 1989 and 1996, 21 skeletally immature patients were treated for osteosarcoma of the extremity. Their average age was 12.6 years (range 9-16 years). We classified the location and extent of the lesion in bone on magnetic resonance imaging (MRI) with reference to the growth plate and joint margin into five subtypes. This classification served as a guide for the level of resection and the type of reconstruction required for a limb salvage procedure. All patients received neoadjuvant chemotherapy using a modified T10 protocol before the definitive operation. These patients were followed up for periods ranging from 11-86 months, with a mean of 35. 5 months. Patients were assessed for (1) local tumour recurrence, (2) metastatic disease, (3) allograft complications and (4) extremity function and joint stability. Excellent function was retained in 2, good in 13 and fair function in 6 patients. The MRI classification proved useful for the resection and provides an insight into the possible functional outcomes.

Three Hong Kong Chinese cases of pretibial epidermolysis bullosa: a genodermatosis that can masquerade as an acquired inflammatory disease.

Three patients in two families presented with many years' history of fragile skin, blisters, erosions and scars affecting almost exclusively the shin areas, accompanied by a variable degree of itching. Two of the patients also had toenail dystrophy. Skin biopsy revealed dermal-epidermal blister formation and milia but no immunohistochemical evidence of immunoglobulin or complement deposition. Electron microscopic study of the lesional and perilesional skin showed very sparse or absent anchoring fibrils. Immunolabelling for type VII collagen using LH 7.2 monoclonal antibody revealed a bright, linear staining pattern at the dermal-epidermal junction. The clinicopathological features were thus compatible with pretibial epidermolysis bullosa, a subtype of dystrophic epidermolysis bullosa. Of note, the inflammatory nature of the skin lesions, and their resemblance to nodular prurigo and hypertrophic lichen planus, had caused diagnostic difficulties in all cases in the past. A high degree of awareness of this rare subtype of epidermolysis bullosa is important to establish the correct diagnosis, to allow for genetic counselling and to plan clinical management.

Bacterial colonization of bone allografts related to increased interval between death and procurement: an experimental study in rats.

Whereas organs from donors must be removed almost immediately after death to maximize organ viability in the recipient, there is a slightly longer window for tissue allograft recovery. To determine the maximum safe interval after death within which bone allografts may be harvested for clinical use, an experimental model was devised using adult Sprague-Dawley (SD) rats and duplicating cadaveric storage techniques. Allografts were procured at increasing time intervals after death. The grafts were then transplanted to 80 living SD rats, and the animals killed at 7 weeks to evaluate any increase in the risk of infection and bacterial colonization. None of the allografts procured within 48 h after death were colonized with bacteria, while 12% of grafts procured at 96 h and 50% of allografts procured at 1 week were colonized. The results suggest that it may be possible to extend the safe period within which cadaveric tissue may be procured for transplantation to up to 96 h following death, provided scrupulous measures to prevent and detect microorganism contamination are followed.

A characteristic dissection microscopy appearance of a renal biopsy of a Fabry heterozygote.

We report a 15-year-old Fabry heterozygote presenting to us with asymptomatic proteinuria. During the dissection-microscopic examination, the glomeruli exhibited a characteristic swollen, glistening and white appearance. They were swollen and bulged out from the surface of the renal core. The glomerular tufts appeared to be filled with opaque and whitish material giving them a pale white discoloration. This appearance is due to the accumulation of glycosphingolipids in visceral epithelial cells of the kidney. This feature is important for the investigation of female patients with asymptomatic proteinuria, as in two thirds of Fabry heterozygotes the characteristic skin lesions are absent, and thus heterozygous Fabry disease may not be considered. We suggest that this easily demonstrable appearance can be the first evidence for the disease and pathologists should be aware of it in future.

Use of low molecular weight heparin in postangioplasty management.

The results of using low molecular weight heparin (LMWH) in postangioplasty management are examined. In comparison to intravenous unfractionated heparin, subcutaneous LMWH caused less groin complications and was simpler and cheaper to be administered by the medical personnel. The incidence of ischaemic complications after angioplasty including acute closure and myocardial infarction, however, remained similar and was not excessive. Subcutaneous administration of LMWH provides and alternative simple and cost-effective strategy for postangioplasty management.

Balloon mitral commissurotomy in a patient with situs inversus and dextrocardia.

A patient with situs inversus and dextrocardia in whom a successful balloon mitral commissurotomy for symptomatic rheumatic mitral stenosis was performed after appropriate modifications in the technique of transseptal catheterization is described.