Abdominoscrotal hydrocele in the infant.
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Abdomen↗
Biomedical subjects
R Kay
Publications and source records attributed to R Kay.
Stroke subtypes among Chinese living in Hong Kong: the Shatin Stroke Registry.
The Shatin Stroke Registry is a prospective study of all patients admitted with acute stroke to a general hospital in Hong Kong where the population is predominantly Chinese. Each patient was examined by a neurologist and 95.5% of the patients had a brain CT. Of 777 patients included in the study, 44.0% had a cortical/subcortical infarct, 18.5% a supratentorial lacunar infarct, 24.2% a supratentorial intracerebral hemorrhage, 5.8% brainstem/cerebellar infarct, 2.9% a brainstem/cerebellar hemorrhage, and 4.5% an uncertain diagnosis. The overall 30-day case fatality rate was 25.4%. Comparison with five stroke registries from the West suggests that intracerebral hemorrhage occurs between two and three times more frequently in the Chinese than in Westerners. Whether there is any difference in the relative frequencies for lacunar infarction remains unclear.
Adult↗
CD24, a signal transducer modulating B cell activation responses, is a very short peptide with a glycosyl phosphatidylinositol membrane anchor.
CD24 is a signal-transducing molecule on the surfaces of most human B cells that can modulate their response to activation signals by antagonizing IL-induced differentiation into antibody-forming cells and inducing proliferation in combination with signals generated by Ag receptors. A cDNA that directs the expression of CD24 on the surfaces of transfected COS cells was cloned by its homology to a cDNA encoding the murine M1/69-J11d heat stable Ag. The CD24 cDNA encodes a mature peptide of only 31 to 35 amino acids that is extensively glycosylated and is attached to the outer surface of the plasma membrane by a glycosyl phosphatidylinositol lipid anchor. Although CD24 is structurally similar to M1/69-J11d, and the two Ag appear to have a common genetic ancestry, the homology of CD24 to the M1/69-J11d Ag is confined to a small cluster of amino acids comprising potential N-linked glycosylation sites. Combined with the differences in expression patterns of the human and murine Ag, this indicates that CD24 and M1/69-J11d may not have equivalent functional roles in lymphoid development. The novel structure of CD24 suggests that signaling could be triggered by the binding of a lectin-like ligand to the carbohydrates projecting from the CD24 peptide, and transduced through the release of second messengers derived from the glycosyl phosphatidylinositol membrane anchor of CD24.
Antigens, CD↗
The analysis of failure time data in crossover studies.
Clinical trials of new drugs in the treatment of angina pectoris frequently make use of exercise tests to evaluate efficacy. The crossover design is often employed. The methods commonly used to analyse the various exercise times, for example, 'time to pain', are insensitive and potentially biased by the manner in which they deal with the censored nature of the data. Survival analysis can be adapted for use in crossover trials, both in a relatively simple way, and also through the full power of the Cox model. This is considerably more sensitive and not subject to the same bias. This methodology leads to the use of median survival times to illustrate treatment effects and this provides a practical interpretation of clinical relevance. The estimation of median survival times in crossover trials poses some special problems. The methodology is illustrated throughout by means of a specific two-period example in which atenolol was compared with the combination of atenolol and nifedipine. The three-period design is also briefly discussed.
Analysis of Variance↗
Asymmetrical weakness in polymyositis associated with neuropathic involvement.
Peripheral nerve involvement is rare in polymyositis and dermatomyositis. We describe a patient in whom the clinical appearance was suggestive of a markedly asymmetrical presentation of polymyositis. Nerve conduction studies, however, were consistent with multiple neuropathies and suggest that neurological involvement may have been the basis of the asymmetrical weakness. Both the muscle weakness and the neurological abnormalities resolved with corticosteroid therapy. This case illustrates a previously undescribed neurological complication of polymyositis.
Humans↗
The site of the lesion causing hearing loss in bacterial meningitis: a study of experimental streptococcal meningitis in guinea-pigs.
The pathological basis of hearing loss in bacterial meningitis was investigated using an animal model of Streptococcus suis meningitis. Forty guinea-pigs were infected after their hearing had been assessed by brain stem auditory evoked potentials. In 17 animals, it was possible to repeat the procedure at the onset of meningitis; this included one animal with subclinical disease. Fifteen animals showed evidence of hearing loss, which on subsequent histological examination was found to be associated invariably with suppurative labyrinthitis. The remaining two animals without hearing loss had normal cochleas. It is suggested that cochlear sepsis rather than eighth cranial nerve involvement by meningeal sepsis is primarily responsible for hearing loss in bacterial meningitis, and that bacteria enter the cochlea via the cochlear aqueduct and not the internal auditory canal. The tissue within the lumen of the cochlear aqueduct may act as a barrier against invasion by micro-organisms, and haemolytic streptococci could cause lysis of this barrier by the exotoxins they produce.
Animals↗
Low ambient temperature increases baroreflex-governed sympathetic outflow to muscle vessels in humans.
Microelectrode multi-unit recordings of muscle nerve sympathetic activity, primarily involved in blood pressure regulation, were made from the right peroneal nerve in 10 healthy subjects during exposure to cold inside a box used for hypothermic surgery. Blood pressure was monitored by an automatic cuff applied to the left arm. Heart activity (ECG) and the temperature inside the box were monitored. Muscle nerve sympathetic activity outflow and blood pressure were stable during 15 minutes initial rest at 22.7 +/- 0.3 degrees C (mean +/- SEM). All subjects increased muscle nerve sympathetic activity and blood pressure with lowering of ambient temperature. The box temperature was 10.5 +/- 0.3 degrees C at the end of the cooling period. With rewarming the changes in muscle nerve sympathetic activity and blood pressure were reversed. Mean outflows of muscle nerve sympathetic activity during initial rest, final phase of cooling period, and post-rewarming were 20.3 +/- 2.7, 26.6 +/- 3.2 and 20.2 +/- 2.8 burst min-1, respectively. Systolic blood pressure during the same periods was 118 +/- 3, 131 +/- 4 and 120 +/- 4 mmHg, respectively, whereas corresponding values for diastolic blood pressure were 73 +/- 2, 82 +/- 2 and 75 +/- 2 mmHg (P less than 0.001 for all variables; (ANOVA). It is concluded that muscle nerve sympathetic activity, while not regarded as being involved in body temperature regulation, is under the influence of ambient temperature and contributes to blood pressure elevation in a cold environment.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Juvenile distal spinal muscular atrophy of upper extremities in Chinese males: a single fibre electromyographic study of arms and legs.
Single fibre electromyography (SFEMG) was performed on six young Chinese males with distal spinal muscular atrophy of the upper extremities. Abnormal SFEMG findings of increased fibre density, jitter and blocking were recorded over both arms and legs in all patients, suggesting a more generalised disturbance than would appear clinically.
Adolescent↗
Environmental temperature and stroke in a subtropical climate.
The effect of environmental temperature on stroke occurrence in a subtropical climate was studied over a 1-year period by documenting the number of strokes (subdivided into cerebral infarct and intracerebral hemorrhage) admitted into a district hospital in Hong Kong at different temperatures. There was no significant correlation between the number of strokes (or its subtypes) per day per temperature category and the environmental minimum or maximum temperature. However, an association was present between the occurrence of cerebral infarcts and maximum temperature on the day of onset in elderly patients aged 70 years and above. Environmental temperature is not a strong risk factor for the occurrence of stroke in a subtropical climate.
Age Factors↗
Hypertension, lipoprotein(a), and apolipoprotein A-I as risk factors for stroke in the Chinese.
We analyzed the serum concentrations of lipids and lipoproteins and the prevalence of other risk factors in a case-control study of 304 consecutive Chinese patients with acute stroke (classified as cerebral infarction, lacunar infarction, or intracerebral hemorrhage) and 304 age- and sex-matched controls. For all strokes we identified the following risk factors: a history of ischemic heart disease, diabetes mellitus, or hypertension; the presence of atrial fibrillation or left ventricular hypertrophy; a glycosylated hemoglobin A1 concentration of greater than 9.1%; a fasting plasma glucose concentration 3 months after stroke of greater than 6.0 mmol/l; a serum triglyceride concentration 3 months after stroke of greater than 2.1 mmol/l; and a serum lipoprotein(a) concentration of greater than 29.2 mg/dl. We found the following protective factors: a serum high density lipoprotein-cholesterol concentration of greater than 1.59 mmol/l and a serum apolipoprotein A-I concentration of greater than or equal to 106 mg/dl. The patterns of risk factors differed among the three stroke subtypes. When significant risk factors were entered into a multiple logistic regression model, we found a history of hypertension, a high serum lipoprotein(a) concentration, and a low apolipoprotein A-I concentration to be independent risk factors for all strokes. The attributable risk for hypertension was estimated to be 24% in patients aged greater than or equal to 60 years. In this population, in which cerebrovascular diseases are the third commonest cause of mortality, identification of risk factors will allow further studies in risk factor modification for the prevention of stroke.
Apolipoprotein A-I↗
The radiological (CT) and clinical sequelae of primary intracerebral haemorrhage.
To determine the radiological and clinical outcome of primary intracerebral haemorrhage, a prospective study was carried out involving computed tomography (CT) of 388 consecutive Chinese patients admitted with acute stroke to a large public hospital in Hong Kong. Further CT and functional assessment were performed 3 months later in 71% of survivors. The patients were admitted over a 6 month period. 120 (31%) were found to have had presumed primary intracerebral haemorrhage. Of these, 64 patients (53%) died within 3 months. From 40 of the 56 survivors who returned for a follow-up study at 3 months, 30 were functionally independent and five mildly disabled; only five were significantly disabled. Follow-up CT showed no residual lesion in 27%, low attenuation areas in 37%, slit-like lesions in 25% and calcification in 10% of patients. The size of residual lesions correlated statistically with the degree of residual disability, although the association was not close. It is concluded that primary intracerebral haemorrhage accounts for a high percentage of strokes among Hong Kong Chinese with more than half of the patients dying within 3 months. Many survivors, in whom follow-up CT appearances are variable, show good functional recovery.
Activities of Daily Living↗
Compliance during lithium treatment, intra-erythrocyte lithium variability, and relapse.
Differential lithium concentrations across the erythrocyte (RBC) membrane have been studied in the search for biological markers in the affective disorders. The methodologic problems of these studies are reviewed with particular reference to compliance effects. We assessed a triad of compliance parameters, including RBC lithium variability, in a group of 60 lithium clinic attenders, in relation to relapse data and diagnostic subgroups. It was found that RBC lithium variability, used in the present study for the first time, related to higher relapse rates on lithium, suggesting that it may be used as an objective medium term compliance parameter. The established patterns of compliance were compared for the diagnostic subgroups.
Bipolar Disorder↗
The validity of inferences based on incomplete observations in disease state models.
In many survival time studies or studies on the progression of a disease, information is often incomplete in the sense that it is known only that a patient has been in certain disease states at several time points. In this paper, conditions concerning the interrelationship between the disease process and the examination scheme (i.e., the pattern of examination times) are derived under which a valid statistical inference is possible. These conditions are confronted with examination schemes that are of practical importance in clinical research. A cancer marker study is used as an example to estimate the magnitude of the potential bias when the conditions derived are violated.
Biometry↗
Renal cell carcinoma with inferior vena cava tumor thrombi.
Renal cell carcinoma is a unique neoplasm because of its common propensity to propagate into the renal vein and inferior vena cava (IVC) as tumor thrombus. Historically, the surgical difficulties encountered in removal of these cancers limited the ability of a single institution to obtain experience with large numbers of instances. Between January 1956 and July 1987, 68 patients with renal cell carcinoma extending into the IVC or right atrium underwent radical nephrectomy with vena cava thrombus extraction at the Cleveland Clinic. Twenty-five patients had partial resection of the IVC with reconstruction. Fifteen patients had partial resection and reconstruction of the IVC; however, because of narrowing of the infrarenal IVC, persisting bland thrombus in the proximal IVC or iliac veins or concern regarding postoperative pulmonary emboli, the infrarenal IVC was either ligated or clipped. Seven patients underwent cavectomy with division of the IVC. A right atriotomy was performed upon 14 patients and cardiopulmonary bypass was used in 20 patients, with 17 also having deep hypothermic circulatory arrest. The tumor thrombus was removed intact in 64 per cent of the patients and in multiple small fragments ("piecemeal") in 36 per cent of the patients. The mortality rate was 7 per cent. Survival was examined relative to extent of vena caval thrombus. Patients with extension into the atrium had a significantly worse prognosis than those with other levels of vena caval involvement. Other factors, such as lymph node status, perinephric fat involvement, resection of IVC and intact or "piecemeal" extraction, did not influence the survival rate. Patients with pre-existing metastases preoperatively had an extremely poor survival rate. The techniques now available for surgical resection of all levels of tumor thrombus of the IVC make resection feasible in most patients. In our opinion, the addition of deep hypothermic circulatory arrest has been a significant advance.
Carcinoma, Renal Cell↗
Expression cloning of a cDNA encoding M1/69-J11d heat-stable antigens.
The differentiation Ag identified by the mAb M1/69 and J11d (commonly referred to as heat-stable Ag) are found in structurally heterogeneous forms on the surfaces of many types of murine hemopoietic cells. The extinction of expression of these antigens is associated with thymocyte maturation and Ig class switching in B cells, as well as terminal differentiation of macrophages. A cDNA encoding the M1/69-J11d peptide was cloned from a hemopoietic progenitor cell line by immunoselection of COS cells transfected with expression libraries. The cloned cDNA is a copy of a gene that is transcribed in M1/69-J11d+ lymphoid, myeloid, and erythroid cells. This gene could be responsible for the expression of all forms of the M1/69-J11d Ag, although there are homologous genes that may encode some forms of the Ag that are specifically expressed in bone marrow. The cloned cDNA encodes a surprisingly small peptide, predicted to contain only 30 amino acids after removal of a signal sequence and displacement of the C-terminal region by the glycosyl-phosphatidylinositol group that anchors the peptide to the cell surface. Almost all of the mass of the M1/69-J11d Ag accumulates through extensive N- and O-linked glycosylation at multiple sites in the short peptide. These carbohydrates are likely to execute the functions of M1/69-J11d Ag, which could be specialized to each cell type as a consequence of differential glycosylation.
Amino Acid Sequence↗
Heterogeneous modifications of the 114/A10 protein of interleukin-3-dependent cells are concentrated in a highly repetitive amino-terminal domain.
The protein 114/A10 is expressed in structurally heterogeneous forms on the surfaces of all murine hemopoietic cells that are responsive to the growth factor interleukin-3, including multipotent progenitors. Despite their structural diversity, all forms of 114/A10 appear to be expressed from a single gene that encodes a peptide with a potential transmembrane segment, three sequences with homology to epidermal growth factor, and an N-terminal domain consisting of eight perfect or near perfect tandem repeats of a 27-amino acid peptide that has a very high content of serine and threonine. Constructed cDNAs that encode deleted or hybrid forms of the 114/A10 protein have been expressed on COS cells in order to localize sites of post-translational modification. The results demonstrate that the structural diversity of 114/A10 is confined to its N-terminal repeat domain and probably arises through extensive O-linked glycosylation within each of the repeats in that domain. The highly modified N terminus of 114/A10 projects from the outer surface of the cell and could serve as a ligand for lectin-like proteins or could modulate the activities of the adjacent epidermal growth factor-like domains of 114/A10.
Amino Acid Sequence↗
The influence of hyperglycemia and diabetes mellitus on immediate and 3-month morbidity and mortality after acute stroke.
Fasting serum glucose, glycosylated hemoglobin, and fructosamine concentrations were determined in 304 consecutive subjects admitted with acute stroke, within 48 hours of ictus. Based on the medical history and these results, subjects were divided into known diabetics, newly diagnosed diabetics, subjects with stress hyperglycemia, and nondiabetics. The type of stroke was classified as lacunar infarct, cerebral infarct, or intracerebral hemorrhage, based on clinical examination by a neurologist and computed tomographic brain scan and/or autopsy. Immediate and 3-month outcomes were examined in relation to (1) fasting glucose, glycosylated hemoglobin, and fructosamine levels by stroke subtypes, and (2) glucose tolerance categories by stroke subtypes. A high fasting glucose level was associated with an increased mortality, but this was observed only among patients with intracerebral hemorrhage. Patients with stress hyperglycemia, but not diabetics, had increased mortality. In spite of having similar glucose concentrations to those patients with stress hyperglycemia, diabetics did not have a worse outcome compared with nondiabetics. It is concluded that the association between glucose concentration and outcome is a reflection of stress relating to stroke severity, rather than a direct harmful effect of glucose on damaged neurons.
Acute Disease↗
Renal sarcomas of childhood.
Renal sarcomas in infants and children are extremely uncommon. Previously classified as Wilms tumors with unfavorable histology, these tumors were thought to be variants of Wilms tumors but in general have a worse prognosis. Our recent experience with 4 cases of renal sarcomas indicate that these tumors must be approached individually and treated appropriately. Their histologic picture and their varying response to surgery and chemotherapy suggest that these unusual tumors are not variants of Wilms tumors but instead sarcomas unrelated to the classic Wilms tumors.
Child↗