Biomedical subjects

Z Huo

Publications and source records attributed to Z Huo.

10 recordsLinked to original sources

PubMed1998

Automated computerized classification of malignant and benign masses on digitized mammograms.

RATIONALE AND OBJECTIVES: To develop a method for differentiating malignant from benign masses in which a computer automatically extracts lesion features and merges them into an estimated likelihood of malignancy. MATERIALS AND METHODS: Ninety-five mammograms depicting masses in 65 patients were digitized. Various features related to the margin and density of each mass were extracted automatically from the neighborhoods of the computer-identified mass regions. Selected features were merged into an estimated likelihood of malignancy by, using three different automated classifiers. The performance of the three classifiers in distinguishing between benign and malignant masses was evaluated by receiver operating characteristic analysis and compared with the performance of an experienced mammographer and that of five less experienced mammographers. RESULTS: Our computer classification scheme yielded an area under the receiver operating characteristic curve (Az) value of 0.94, which was similar to that for an experienced mammographer (Az = 0.91) and was statistically significantly higher than the average performance of the radiologists with less mammographic experience (Az = 0.81) (P = .013). With the database used, the computer scheme achieved, at 100% sensitivity, a positive predictive value of 83%, which was 12% higher than that for the performance of the experienced mammographer and 21% higher than that for the average performance of the less experienced mammographers (P < .0001). CONCLUSION: Automated computerized classification schemes may be useful in helping radiologists distinguish between benign and malignant masses and thus reducing the number of unnecessary biopsies.

Breast Neoplasms↗

PubMed1997

A glycoprotein pneumococcal conjugate vaccine primes for antibody responses to a pneumococcal polysaccharide vaccine in Gambian children.

BACKGROUND: Streptococcus pneumoniae is a major cause of acute respiratory infections and acute bacterial meningitis in children. Pneumococcal polysaccharide vaccines are poorly immunogenic in this highly vulnerable group, but protein polysaccharide conjugate vaccines are likely to be more effective. OBJECTIVES: To determine whether immunization of infants with a pneumococcal conjugate vaccine induces immunologic memory. METHODS: Eighty-four Gambian children, who had been vaccinated previously with two or three doses of a pentavalent pneumococcal conjugate vaccine (CRM197) or with a Haemophilus influenzae type b (Hib) conjugate vaccine were immunized when approximately 2 years old with a 23-valent pneumococcal polysaccharide vaccine, and a blood sample was obtained 10 days later. Pneumococcal antibody titers in prevaccination and postvaccination sera were measured by enzyme-linked immunosorbent assay and by an opsonophagocytic assay. RESULTS: On revaccination with a pneumococcal polysaccharide vaccine, children who had previously received pneumococcal conjugate vaccine had higher antibody concentrations to each of the five polysaccharide components of the conjugate vaccine than did control children. For type 6B polysaccharide, which is poorly immunogenic in young children, postvaccination antibody concentrations were 0.37, 27.6 and 50.9 microg/ml in children who had received no previous pneumococcal immunization or two or three doses of conjugate vaccine, respectively. Type 14 antibodies produced after revaccination were of high avidity and had opsonic activity. CONCLUSION: Vaccination of young infants with two or three doses of a pneumococcal conjugate vaccine primes the immune system to respond strongly and rapidly on subsequent exposure to pneumococcal polysaccharide.

Antibodies, Bacterial↗

PubMed1997

Severe pneumococcal disease and temporary splenic dysfunction.

We report a patient presenting with pneumonia in whom temporary splenic dysfunction was diagnosed by counting pitted red blood cells. This under-recognised condition caused a transient immunosuppression which may have had serious implications for our patient's recovery.

Adult↗

PubMed1997

The glial glutamate transporter in hyperammonemia and hepatic encephalopathy: relation to energy metabolism and glutamatergic neurotransmission.

Abnormalities in glutamate metabolism and glutamatergic neurotransmission appear to play a major role in the pathogenesis of hyperammonemia and hepatic encephalopathy. Astrocytes may be involved in these derangements as ammonia has been shown to impair the ability of these cells to take up glutamate. This study presents a northern blot analysis of the GLT-1 glutamate transporter in hyperammonemic rats, and in rats with thioacetamide-induced acute liver failure. Our findings demonstrate a downregulation of GLT-1 mRNA in both conditions. This article examines the potential impact of deficits in glutamate uptake on energy metabolism and glutamatergic neurotransmission in the context of abnormalities in glial-neuronal interactions. We propose that an ammonia-induced abnormality in astroglial glutamate uptake constitutes a critical aspect in the pathogenesis of hepatic encephalopathy and other hyperammonemic conditions.

ATP-Binding Cassette Transporters↗

PubMed1995

Analysis of spiculation in the computerized classification of mammographic masses.

Spiculation is a primary sign of malignancy for masses detected by mammography. In this study, we developed a technique that analyzes patterns and quantifies the degree of spiculation present. Our current approach involves (1) automatic lesion extraction using region growing and (2) feature extraction using radial edge-gradient analysis. Two spiculation measures are obtained from an analysis of radial edge gradients. These measures are evaluated in four different neighborhoods about the extracted mammographic mass. The performance of each of the two measures of spiculation was tested on a database of 95 mammographic masses using ROC analysis that evaluates their individual ability to determine the likelihood of malignancy of a mass. The dependence of the performance of these measures on the choice of neighborhood was analyzed. We have found that it is only necessary to accurately extract an approximate outline of a mass lesion for the purposes of this analysis since the choice of a neighborhood that accommodates the thin spicules at the margin allows for the assessment of margin spiculation with the radial edge-gradient analysis technique. The two measures performed at their highest level when the surrounding periphery of the extracted region is used for feature extraction, yielding Az values of 0.83 and 0.85, respectively, for the determination of malignancy. These are similar to that achieved when a radiologist's ratings of spiculation (Az = 0.85) are used alone. The maximum value of one of the two spiculation measures (FWHM) from the four neighborhoods yielded an Az of 0.88 in the classification of mammographic mass lesions.

Automation↗

PubMed1994

[Experimental study of antiinfection effect of topical "moist ointment" in burn wound infection].

A controversy on the therapeutic effect of topical "moist ointment" in burns has been noticed recently. An experimental study is designed for the evaluation of its antibacterial and antiinfection effect. A 20% fullthickness burn wound is produced on SD rat back, and they are seeded with 10(9) CFU of Pseudomonas aeruginosa ATCC-27853. "Moist ointment", cream base, 1% silver sulfadiazine (Ag-SD) cream or 1.2% silver norfloxacin (Ag-FLX) cream is topically applied to the burn wounds at various time interval of 10 min, 8h, 24h, and 48h, after the inoculation of Pseudomonas aeruginosa. Topical therapy lasted for 48h, with dressing change once a day but twice a day for "moist ointment" therapy only. Bacterial counts of subeschar tissue and heart blood culture, and histopathologic study of the wounds are made as laboratory criteria. A modified agar well diffusion (AWD) test is performed as a bacterial inhibitory study using Pseudomonas aeruginosa ATCC-27853, E. coli ATCC-25922, or Staphylococcus aureus ATCC-25923. Results of the study show that Ag-FLX cream has a strong antibacterial effect and Ag-SD cream a moderate effect. However, "moist ointment" and cream base do not show antibacterial effect. Bacterial counts of subeschar tissue and histopathologic study of the infected burn wounds show that more than 70% of the animals in the "moist ointment" group have invasive wound infection, and the incidence of septicemia with Pseudomonas aeruginosa is 50% as determined by blood cultures. The above mentioned results indicate that "moist ointment" has no antibacterial and anti-infection effect.

Administration, Topical↗

PubMed1993

[The analysis of human DNA fingerprints by the synthetic oligonucleotide probe].

In order to test the practical applicability of oligonucleotide fingerprinting we have investigated 50 unrelated individuals, 11 members in two families and one pair of twin using the probe (CAC)5/(GTG)5. Except the monozygotic twins highly variable patterns were demonstrated, even in a family. The probability of chance association between random individuals was calculated as 3.8 x 10(-10). It seems reasonable to conclude that (CAC)5/(GTG)5 fingerprints are completely individual-specific. The results of the pedigree study showed that the inheritance of alleles was in keeping with the Mendelian Law. This method is not so costly and labor-intensive as the conventional Southern blotting. It increases the speed and lessen the complexity of RFLPs study.

DNA Fingerprinting↗

PubMed1993

[An evaluation of DNA fingerprinting with oligonucleotide probe for forensic purposes].

The synthetic oligonucleotide probe (CAC)5/(GTG)5 for DNA, fingerprinting was studied in this paper. The incomplete pattern of DNA fingerprints was obtained from bloodstains up to three years old, which were kept at room temperature. The identical results were achieved from various human organ tissues of the same individual. DNA fingerprints from vaginal swabs was the same as that obtained from the male donor's blood. The discernible DNA fingerprints were obtained with as little as 250ng of genomic DNA. Besides, using restriction enzyme Hae III instead of Hinf I to digest human DNA, the highly polymorphic hybridization pattern was also obtained. A practical case was tested by Hinf I and Hae III digestion, respectively. The results demonstrated that the (CAC)5/(GTG)5 was a suitable probe for DNA fingerprinting in forensic practice.

Base Sequence↗

PubMed1992

[DNA repair capacity measurement and possibility of heterozygote detection using nucleoid sedimentation technique among members taken from 3 xeroderma pigmentosum (XP) families].

The nucleoid sedimentation test was used to analyse the DNA repair capacity in 35 members taken from 3 xeroderma pigmentosum (XP) families after their peripheral blood lymphocytes being exposed to UV irradiation or N-methyl-N-nitro-N-nitrosoguanidine (MNNG) at a dose of 2.5 microJ/mm2 and 2 micrograms/ml respectively. The results showed that the 6 XP patients all failed to repair their damaged DNA even after 20-hour incubation at 37 degrees C. The repair ratios were 0.61 +/- 0.13 for UV and 0.44 +/- 0.15 for MNNG while those of non-related normal members usually reached 0.96 +/- 0.07 and 0.71 +/- 0.07 for both UV and MNNG after 11-hour incubation. It is interesting to note that 9 obligatory heterozygotes (parents and grandparents of XP patients) and 4 highly possible heterozygotes (blood relatives of XP patients) also showed very poor DNA repair capacity: they could not accomplish their repair process even after 20-hour incubation. It has been showed that the nucleoid sedimentation test can probably be used to pick out the heterozygotes in XP families.

Adolescent↗

PubMedDate not supplied

[Multi-locus DNA fingerprints using oligonucleotide probe (CAC)5/(GTG)5 in the Chinese population].

In order to test the practical applicability of oligonucleotide fingerprinting in China we have investigated unrelated individuals, family members and a pair of twins from the Beijing area using the probe (CAC)5/(GTG)5. Except for the monozygotic twins highly variable banding patterns were demonstrated as expected for the randomly selected individuals but also for the relatives. On the basis of an initial survey of 50 unrelated individuals the calculated probability for obtaining by chance two identical multilocus patterns is very small (less than 1.93 x 10(-13). Therefore it seems reasonable to conclude that like in caucasians, (CAC)5/(GTG)5 fingerprints are completely individual-specific also in this population. Therefore they have already been used successfully for identification purposes and paternity tests in many actual cases.

China↗