Resection of hepatocellular carcinoma with diaphragmatic invasion

Fourteen consecutive patients with hepatocellular carcinoma (HCC) and diaphragmatic invasion found during operation and confirmed histopathologically were studied. They were treated by resection of the liver tumour en bloc with part of the diaphragm. Eight of the 14 patients had a diaphragmatic hump on chest radiography. Preoperative ultrasonography, computed tomography and hepatic angiography were unable to diagnose diaphragmatic invasion in these patients. A control group of 14 closely matched patients were selected from 98 undergoing curative resection for HCC during the period of the study. No evidence of a diaphragmatic hump was found in the control patients (P < 0.001). There was no significant difference in survival, operative morbidity or mortality rates between the two groups. In patients with HCC situated in the dome of the liver, the presence of a diaphragmatic hump on chest radiography strongly suggests invasion of the diaphragm. There was no difference in outcome in patients with or without diaphragmatic invasion; the tumour should be resected if the patient is fit for operation.     

Enhanced microwave performance of ion-implanted MESFET with graded GaAs/AlGaAs heterojunctions

Ion-implanted MESFETs have been fabricated on an inverted GaAs/AlGaAs heterostructure. The aluminium concentration in the AlGaAs is graded from 0% at the substrate to 30% at the heterointerface. A maximum extrinsic transconductance of 410 mS/mm is achieved with 0.5 mu m gate devices. This heterojunction ion-implanted FET (HIFET) also exhibits enhanced microwave performance, especially at low drain current, when compared to conventional ion-implanted GaAs MESFETs. At 20% of I/sub dss/, the current gain cutoff frequency f/sub t/ is 40 GHz, which increases up to a maximum value of 47 GHz as the drain current rises. These characteristics of high f/sub t/ and high gain at low current are advantageous for low-noise applications.<>     

Prevalence and genotypes of alpha- and beta-thalassemia carriers in Hong Kong -- implications for population screening

BACKGROUND: The thalassemias are common in southern China. We determined the prevalence of heterozygous carriers of these genetic disorders in Hong Kong and assessed the feasibility of a community-based screening program. METHODS: An educational and screening program for the thalassemias was carried out in three high schools with a total of 2420 students. Seventy-five percent of the students agreed to undergo screening, which consisted of blood counts, hemoglobin electrophoresis, serum ferritin measurements, and DNA analyses. RESULTS: Of the 1800 blood samples tested, 150 (8.3 percent) had microcytosis (mean corpuscular volume, <80 microm3). Ninety students (5.0 percent) were carriers of alpha-thalassemia, of whom 81 (4.5 percent) were carriers of the Southeast Asian type of deletion, in which both alpha-globin genes on the same chromosome 16 are deleted. Sixty-one students (3.4 percent) were carriers of either beta-thalassemia or the mutation coding for hemoglobin E. Six students were carriers of both alpha- and beta-thalassemias. On the basis of these figures, the estimated numbers of pregnancies in Hong Kong in which the fetus is at risk for homozygous alpha-thalassemia and beta-thalassemia major or intermedia are 145 and 80 per year, respectively. In Hong Kong the actual numbers of women referred for prenatal diagnoses of these disorders are approximately 95 and 40 per year, respectively. CONCLUSIONS: Despite the availability of hospital-based screening and prenatal diagnosis for many years in Hong Kong, many women carrying fetuses at risk for thalassemia are not referred for genetic counseling. A community-based program of education, screening, and counseling is needed in Hong Kong and southern China.     

Real-time ultrasonic monitoring of fiber-matrix debonding in ceramic-matrix composite

Real-time ultrasonic techniques were developed for monitoring damage in a unidirectional ceramic-matrix composite under longitudinal tensile loading. Specifically, shear-wave transducers producing waves polarized in the transverse to the fiber direction were used in contact with the specimen to detect the initiation and propagation of fiber—matrix debonding, and to determine the transverse shear modulus and its degradation. The ultrasonically measured transverse shear modulus and its degradation was in reasonably good agreement with a prediction based on a modified shear lag model and interpolation between available solutions for fully bonded and fully unbonded fibers.     

Compatibility of polystyrene and poly(methyl methacrylate) of various molecular weights in toluene

Gel permeation chromatography has been successfully used to determine the compositions of the conjugate phases in the system of polystyrene and poly(methyl methacrylate) with toluene as solvent. Application of this method to equilibrated samples yields tie lines, binodal curves, and plait points. Polymer–polymer compatibility and the polymer–polymer interaction parameters at the plait points in this system were found to be strongly dependent on the molecular weights of the polymers.     

A theoretical framework of uplink macroscopic optimization for multicell systems with multiuser detection

In this paper, we consider a system with K client users (single antenna), n/sub B/ base stations (each has single antenna), as well as a centralized controller. All the base stations operate at the same frequency and have optimal multiuser detection (MUD) per base station. The MUD at the base station is able to cancel only the intracell interference but not the intercell interference. A client user is associated with a single base station at any time. We consider a general problem of uplink macroscopic optimization (or macroscopic resource management) where the centralized controller dynamically determines an appropriate association mapping of the K users with respect to the n/sub B/ base stations over a macroscopic time scale. We propose a novel multicell capacity region as well as an analytical framework for the above macroscopic optimization problem. A simple conventional rule is to associate a user with the strongest base station (camp-on-the-strongest-cell) and this has been widely employed in conventional cellular systems. However, based on the optimization framework, we found that this conventional approach is in fact not optimal when MUD is employed at the base station. We show that the optimal macroscopic optimization algorithm is of exponential complexity and we propose a simple greedy algorithm as a feasible solution. It is shown that the macroscopic optimization gain over the conventional approach increases with decreasing path loss exponent due to large area of overlapping.     

Delayed mid-ileal perforation secondary to acute-on-chronic ischaemia after a diagnostic colonoscopy

Perforation occurring at a remote site of the bowel after diagnostic colonoscopy is rare. A 61-year-old man presenting with bloody diarrhoea underwent colonoscopy. A dynamic ileus developed in less than 1 day, and mid-ileal perforation occurred 7 days after the procedure. It is suggested that high air pressure during colonoscopy further compromised the reduced blood flow in the mid-ileum, which had underlying chronic ischaemia, leading to perforation. Our patient constitutes the first reported case of small-bowel perforation after colonoscopy due to pre-existent ileal ischaemia.     

A corneal endothelium cell analyzer for slit lamps

An optical system that attaches to a slit lamp is an alternative to the cost and limitations of specular microscopes. In order to overcome the limitations of subjective assessment of all the endothelial layers, the difficulties of manipulation, high cost, and analysis of several parts of the cornea, we have developed a system that can be attached to the slit lamp (290/spl times/ nominal magnification of the image of the cells displayed on a PC monitor and a dedicated software for image treating and cells counting). Results are in good agreement with measurements done in specular microscopes (correlation coefficient is 0.98081) and the automatic counting method is also in good agreement with the interactive counting method (correlation coefficient is 0.95798).     

Hypophysectomy or adrenalectomy of rats with insulin-dependent diabetes mellitus partially restores their responsiveness to growth hormone

The studies reported herein were conducted to confirm that the pituitary gland is involved in maintaining growth hormone (GH) resistance in rats with insulin-dependent diabetes mellitus (IDDM) and to determine whether the adrenocorticotropic hormone (ACTH)-adrenal cortical axis is responsible. The rats were made diabetic by injecting streptozotocin (85 mg/kg body wt) IP once daily on two consecutive days. They were then injected with 15 IU insulin SC twice daily on two consecutive days to enable them to survive hypophysectomy or adrenalectomy. Intact nondiabetic (NonDb), diabetic (Db), hypophysectomized diabetic (HxDb), and adrenalectomized diabetic (AxDb) rats were injected twice daily with 50 micrograms porcine (p) GH or with 0.9% saline for 2 weeks following the surgeries. Serum glucose levels of the saline-injected Db, HxDb, and AxDb rats were significantly greater than those of the NonDb rats by 106%, 65% and 49%, respectively. However, the levels in the HxDb and AxDb animals were significantly lower than those of the Db group by 20% and 28%, respectively. Injections of pGH into NonDb rats increased serum glucose concentrations by 38%, over their saline-treated controls, and by 29% in AxDb rats. This diabetogenic effect of GH was not seen in any other group. Administration of pGH to Db rats failed to increase body weight gain, tall growth, tibial epiphysial plate width, or serum IGF-I concentration over saline-injected controls. By contrast, HxDb and AxDb rats injected with pGH showed significant increases in all four growth parameters. Total serum IGF-I concentrations in AxDb rats injected with pGH equaled those in NonDb controls. To determine whether the lack of corticosterone (B) in the AxDb rats was responsible for the reduced hyperglycemia and restored responsiveness to pGH, AxDb rats were given B in their drinking water at 5 or 25 micrograms/ml. Administration of B reduced the beneficial effects of adrenalectomy by restoring hyperglycemia and growth impairment, and partially restored resistance to the pGH injections. These studies confirm that the pituitary contributes to diabetic growth impairment and show that the ACTH-adrenal cortical axis is primarily responsible for the GH-resistant state that develops in rats with IDDM.