胎盘组织液氨基酸的含量测定及层析鉴别

本文采用层析法进行鉴定,用氨基酸分析仪测氨基酸的含量,为胎盘组织液的质量标准提供可靠依据。本法准确率为99%。     

A perspective on measurement of mutations in vivo.

The development of transgenic mouse lines with target genes that are suitable for tissue-specific mutagenesis studies is an important contribution to the field of environmental mutagenesis. These models can accommodate many of the questions relating to metabolism, distribution and relative potency of mutagens as well as providing a more comprehensive system for the identification of mutagens. However, the lesions that the field has learned about methods, development and validation from the use of in vitro systems must be applied to the development and validation of transgenic models.     

Automatic discrimination of myoelectric signals via parallel cascade identification

It has recently been shown that it is possible to discriminate accurately among myoelectric signals underlying different muscle contraction types, specifically elbow flexion and extension and forearm pronation and supination. It was reported that once a number of distinctive features had been extracted from the myoelectric signals, a neural network could be trained to distinguish the contraction types with an impressively high accuracy. In the present paper, we show that a technique known as parallel cascade identification can be used to construct classifiers that can also accurately, differentiate the contraction types. The use of parallel cascades has the benefit of dispensing with the need for feature extraction, so that raw myoelectric signal data can be used directly. In addition, very little data are required to train the parallel cascades to distinguish accurately novel incoming myoelectric signals. Results of using parallel cascades to distinguish foream pronation, supination, and elbow flexion are presented.     

Diagnostic performance of arginase activity in colorectal cancer

Arginase activity was measured in serum and biopsy from healthy individuals and colorectal cancer patients. Arginase activity in tumor samples (87±7.7 U/g tissue) was significantly higher than in controls (40.7±3.3 U/g tissue). However, serum arginase activity did not show any significant change in both groups. Finally, the micromethod used to quantify arginase activity in this study is superior to other methods because it has increased sensitivity, requires less sample, and is less time-consuming. Arginase differences are significant, according to the t-test (P<0.05). Received: 14 September 2001 / Accepted: 6 February 2002     

A PCR–restriction fragment length polymorphism assay to genotype human metapneumovirus

Human metapneumovirus (hMPV) genotypes A and B show epidemiological and probably clinical differences. This report describes a fast and simple PCR–restriction fragment length polymorphism (PCR-RFLP) assay, involving digestion of the fusion protein gene with Tsp 509I, that allows lineages A1, A2, B1 and B2 to be distinguished. The assay should help in elucidating the epidemiology of hMPV, and possibly in predicting the severity of clinical infection.     

A String Matching Computer-Assisted System for Dolphin Photoidentification

This paper presents a syntactic/semantic string representation scheme as well as a string matching method as part of a computer-assisted system to identify dolphins from photographs of their dorsal fins. A low-level string representation is constructed from the curvature function of a dolphin's fin trailing edge, consisting of positive and negative curvature primitives. A high-level string representation is then built over the low-level string via merging appropriate groupings of primitives in order to have a less sensitive representation to curvature fluctuations or noise. A family of syntactic/semantic distance measures between two strings is introduced. A composite distance measure is then defined and used as a dissimilarity measure for database search, highlighting both the syntax (structure or sequence) and semantic (attribute or feature) differences. The syntax consists of an ordered sequence of significant protrusions and intrusions on the edge, while the semantics consist of seven attributes extracted from the edge and its curvature function. The matching results are reported for a database of 624 images corresponding to 164 individual dolphins. The identification results indicate that the developed string matching method performs better than the previous matching methods including dorsal ratio, curvature, and curve matching. The developed computer-assisted system can help marine mammalogists in their identification of dolphins, since it allows them to examine only a handful of candidate images instead of the currently used manual searching of the entire database. © 2000 Biomedical Engineering Society. PAC00: 8780Tq, 4230Sy, 0705Pj     

Peak Identification in Visual Evoked Potentials

Waveform patterns evoked by 4 intensities of flash in normal subjects were studied in relation to intersubject variability. Time-frequency distribution curves of all peaks occurring between 11 and 280 msec after flash onset and meeting minimal criteria were obtained from 46 males. These distributions closely corresponded to similar data reported by others for single intensity stimulation. An algorithm was developed which identified in 67 to 100% of instances a single “peak event’ within the time ranges of each of 6 peak distributions. Many peak events appeared and disappeared within the 4 intensity sets of individuals. Latencies were obtained for these peak events. Application of the algorithm to a replicate sample of 29 Ss, which included 8 females, indicated generalizability. Test-retest data on 15 Ss showed its reliability. The data suggest that methodology significantly contributes to the variability of peak identification among subjects. This may be reduced by employing multiple intensities of stimulation.     

Model identification and estimation of organ-function parameters using radioactive tracers and the impulse-response function

Examination of the input-output events in functioning organs by the use of the impulse-response function (IRF) for a radioactive tracer is gaining more and more ground in nuclear medicine. This study summarizes the development of deconvolution analysis, laying special stress on the model-free approach. System linearity and time invariance are discussed, and means of eliminating noise in IRFs originating from the input and organ-time-activity curves are outlined. Typical IRFs are illustrated by flow diagrams, time-domain curves, and their representation by Laplace transforms. The cases of nondiffusible and diffusible tracers as well as parenchymally extracted and transported substances are discussed. Methods for the derivation of models and for the calculation of physiologically important parameters from theIRFs are suggested.At present, a guest scientist at the Institute for Medicine, Nuclear Research Center Jülich, Jülich, Federal Republic of Germany     

Perinatal mortality trends in a referral hospital

A comparative study of perinatal mortality patterns over a period was conducted at a teaching hospital of South India. Among the 6,048 babies born from January 1984 to December 1985 (Group A), there were 265 (43.8/1000) still births and 127 (22.0/1000) early neonatal deaths. Three hundred and thirty seven (41/1000) babies were still born and 235 (29.8/1000) early neonatal deaths out of 8,215 deliveries during 1992–93 (Group B). The perinatal mortality rate (PMR) in Group A and B were 57.9/1000 and 57.7/1000 respectively. Unbooked cases accounted for the majority (> 75%) of perinatal deaths during both the periods. The overall mortality rates in unbooked cases were three to four times higher than booked cases. Among the various causes of still births, antepartum haemorrhage and uterine rupture had increased. Septicaemia was the major cause of early neonatal deaths in Group A, but in Group B birth asphyxia and prematurity were the leading causes. Effective interventions like creating awareness among the target population to utilise maternal and child health services and early referral of high risk cases with improved intranatal and perinatal care can decrease the perinatal mortality.