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131.
132.
W. S. Ng B. L. Davies A. G. Timoney R. D. Hibberd 《Medical & biological engineering & computing》1993,31(4):349-354
A new way of applying transurethral ultrasound scanning in the common surgical procedure of the transurethral resection of
the prostate is described. The scanning is incorporated as part of a robotic procedure for surgery, so that the overall time
spent in an operation can be further shortened, and a safe and accurate operation can be achieved. The prostate dimensions
obtained pre-operatively by the transrectal method and those obtained operatively are compared. A robotic system, which was
developed specifically to remove prostatic adenoma automatically, is discussed. The system, called a motorised frame, is briefly
described, together with its predecessor, a manual frame, in relation to ultrasound measurements. Sizing of the prostate pre-operatively
using transrectal ultrasound methods is discussed, using both the manual and the motorised frame. The shortcomins of transrectal
ultrasound for use in a robotic procedure are highlighted. 相似文献
133.
In Vitro and In Vivo Characterization of MEMS Microneedles 总被引:1,自引:0,他引:1
Transdermal drug delivery TDD systems have many advantages but are conventionally limited by the low permeability of skin. The idea of using microneedles to painlessly penetrate the topmost impermeable stratum corneum has previously been put forward. In this paper, the fabrication of solid and hollow silicon microneedles with straight side-walls and with the following dimensions: 20–100 m in diameter and 100–150 m in length is described. In vitro tests demonstrate that with prior solid microneedle application, transdermal drug transport is significantly increased by 10–20 times, with the degree of enhancement being related to needle diameter. In vivo tests in diabetic animals, however, were unable to demonstrate any delivery of insulin through the hollow microneedles. It is proposed that two factors, microneedle length and tip sharpness, have to be improved for systemic drug delivery to be seen in vivo. 相似文献
134.
135.
A novel regulation mechanism of DNA repair by damage-induced and RAD23-dependent stabilization of xeroderma pigmentosum group C protein 总被引:16,自引:0,他引:16
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Ng JM Vermeulen W van der Horst GT Bergink S Sugasawa K Vrieling H Hoeijmakers JH 《Genes & development》2003,17(13):1630-1645
Primary DNA damage sensing in mammalian global genome nucleotide excision repair (GG-NER) is performed by the xeroderma pigmentosum group C (XPC)/HR23B protein complex. HR23B and HR23A are human homologs of the yeast ubiquitin-domain repair factor RAD23, the function of which is unknown. Knockout mice revealed that mHR23A and mHR23B have a fully redundant role in NER, and a partially redundant function in embryonic development. Inactivation of both genes causes embryonic lethality, but appeared still compatible with cellular viability. Analysis of mHR23A/B double-mutant cells showed that HR23 proteins function in NER by governing XPC stability via partial protection against proteasomal degradation. Interestingly, NER-type DNA damage further stabilizes XPC and thereby enhances repair. These findings resolve the primary function of RAD23 in repair and reveal a novel DNA-damage-dependent regulation mechanism of DNA repair in eukaryotes, which may be part of a more global damage-response circuitry. 相似文献
136.
Characterization of a 105-kDa plasma membrane associated glycoprotein that is involved in West Nile virus binding and infection 总被引:3,自引:0,他引:3
This study attempts to isolate and characterize West Nile virus-binding molecules on the plasma membrane of Vero and murine neuroblastoma cells that is responsible for virus entry. Pretreatment of Vero cells with proteases, glycosidases (endoglycosidase H, alpha-mannosidase), and sodium periodate strongly inhibited West Nile virus infection, whereas treatments with phospholipases and heparinases had no effect. The virus overlay protein blot detected a 105-kDa molecule on the plasma membrane extract of Vero and murine neuroblastoma cells that bind to WN virus. Treatment of the 105-kDa molecules with beta-mercaptoethanol resulted in the virus binding to a series of lower molecular weight bands ranging from 30 to 40 kDa. The disruption of disulfide-linked subunits did not affect virus binding. N-linked sugars with mannose residues on the 105-kDa membrane proteins were found to be important in virus binding. Specific antibodies against the 105-kDa glycoprotein were highly effective in blocking virus entry. These results strongly supported the possibility that the 105-kDa protease-sensitive glycoprotein with complex N-linked sugars could be the putative receptor for WN virus. 相似文献
137.
Dr C. K. Kwoh M. Y. Teo W. S. Ng S. N. Tan L. M. Jones 《Medical & biological engineering & computing》1998,36(6):768-771
In a computerised ultrasound image guidance for automated prostatectomy system, it is necessary to identify a smooth, continuous
contour for the prostate (boundary) from the ultrasound image. The radial bas-relief (RBR) method, which has been reported
previously, can extract a skeletonised image from an ultrasound image automatically. After this process the prostate boundary
is clearly revealed. However, analysis of the image is far from complete, as there are many spurious branches that create
too much ambiguity for the system to define the actual boundary. There are also sections missing from the prostate boundary.
Therefore further post-processing is required to describe and define the prostate boundary. In the paper, the harmonics method
is used to describe the prostate boundary. The harmonics method uses Fourier information for noise removal and encodes a smooth
boundary. The results of using the harmonics method after application of the RBR method on ultrasound images are presented.
Factors that affect the performance are also highlighted and discussed. 相似文献
138.
Previous studies analysing the incidences of mitochondrial DNA (mtDNA) deletions and mtDNA content in unfertilized oocytes in relation to donors' age have been controversial. The objective of the study was to compare these two parameters in unfertilized oocytes and relate them to the donors' age. Fifty-two women donated 155 unfertilized metaphase II (MII) oocytes. The incidence of 4977 bp deletion was 34.6%, and the mtDNA copy number was 598 350 +/- 265 862. Women >or=35 years of age had a significantly higher incidence of 4977 bp deletion, lower mtDNA copy number, higher FSH level and poorer ovarian response when compared with younger women. The mtDNA copy number was negatively correlated with the donor's age. The higher incidence of mtDNA deletion and lower mtDNA copy number in older women suggested that these two parameters may reflect ovarian ageing. 相似文献
139.
140.
Ng VL Kraemer R Hogan C Eckman D Siobal M 《American journal of clinical pathology》2000,114(1):128-138
In response to a $350,000 laboratory budget cut and closure of an intensive care unit-based laboratory and a desire to maintain turnaround times of 10 minutes or less, a multidisciplinary group developed and implemented point-of-care (POC) testing. Only blood gases (pH, PO2, and PCO2) and ionized calcium values were deemed essential stat tests. Three commercially available POC blood gas devices were evaluated; all yielded results comparable to in-house reference methods. The 1 device with a US Food and Drug Administration-approved method for ionized calcium testing and with an existing interface for laboratory information systems was selected. Fiscal analysis predicted annual savings of approximately $225,000. POC blood gas analysis was implemented in April 1996 coincident with closure of the intensive care unit-based laboratory. Clinical laboratories and POC blood gas test volumes remained constant through August 1998; in contrast, the number of ionized calcium tests decreased dramatically after April 1996. In August 1998, clinically significant (i.e., artificial ventilation parameters would have been altered based on test results) discrepant PCO2 values were observed sporadically and noted only with patient specimens, not with commercial controls or electronic simulators. Because investigation failed to identify the cause, use of the POC device was discontinued in September 1998. 相似文献