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Biomedical subjects

N J Wang

Publications and source records attributed to N J Wang.

At least 37 records · Page 2Linked to original sources
PubMed1994

Use of dental hygienists and returns to scale in child dental care in Norway.

The purpose of this study was to investigate, in the provision of dental care for children, technically and economically efficient combinations of dentists and dental hygienists and to study returns to scale by analyzing production functions. Data from 137 dental health clinics were analyzed. Output was registered as the number of 3-18-yr-old children to whom the clinic delivered complete dental care. Resource input was registered as hours spent by dentists, dental hygienists and dental assistants to deliver care to the children. The average clinic that employed dental hygienists used one hygienist hour per three dentist hours for child dental care. It would save dentist time, but not costs, to extent the use of hygienists. Increased use of dental hygienists might be economically efficient if the work distribution between the personnel groups were changed, for example, by delegating more examinations and preventive care to hygienists. There were technical opportunities for further substitution of dental hygienists for dentists both by introducing dental hygienists in the clinics that only used dentists in child dental care and by extending use of hygienists in clinics that already employed hygienists. This study found no productivity gain from centralizing treatment of children in large dental clinics.

Adolescent↗
PubMed1994

Variation in clinical time spent by dentist and dental hygienist in child dental care.

In a field project in the Public Dental Service in Norway, 4000 children aged 5 to 18 years were examined and given preventive care by dental hygienists. The study describes the clinical time spent providing child dental care when hygienists examined all children and referred to dentists those children who required care hygienists were not qualified to deliver. Of all clinical time spent, 56% was dentist time and 44% was hygienist time. A high proportion of children without dental caries did not consume dentist resources at all. More than 40% of the dentist time was consumed by the 10% of the children with most new decayed teeth. In conclusion, the project showed that in a child population with low caries increment, a substantial proportion of children received all dental care from hygienists, so that dentist resources were saved for other groups. However, although hygienists were used as first-line personnel, a considerable quantity of dentist time was spent on dental care for children.

Adolescent↗
PubMed1994

Productivity in dental care for children. Factors influencing the time spent delivering dental care.

The cost of dental services is related to their productivity. The purpose of the study was to identify factors influencing productivity, measured as time spent providing dental care per child under care, per year, in public dental clinics. The time was expected to vary with characteristics of the patients, the personnel and the clinics. Time spent by dentists and dental hygienists delivering dental care for children aged three to 18 years was obtained from 137 public dental clinics. The data showed substantial variation in productivity between clinics. Multiple regression analysis revealed that the time spent per child was associated with interval between examinations, proportion of male dentists, ratio of dental assistants to dentists, proportion of child treatment time given by dental hygienists and proportion of all treatment time spent on child patients. These variables explained 43 per cent of the variance in the total time spent by dentists and hygienists and 41 per cent of the variance in dentists' time. Individual dentists and hygienists may reduce the mean time spent per child by extending recall intervals. On an administrative level, dentists' time per child may be reduced by employing more dental assistants or dental hygienists and allowing dentists to treat patient groups other than children. It is concluded that productivity in dental care for children in the public dental services may be influenced in several ways, both by clinical and administrative decisions.

Adolescent↗
PubMed1994

[c-myc gene and p53 protein expression in human primary liver carcinoma].

Photobiotin-labelled c-myc gene probe was used to study primary liver carcinoma (PHC) by in situ hybridization on the paraffin sections as well as immunohistochemistry staining for p53 protein expression in 42 cases from high liver cancer incidence regions. The results are as follows: c-myc gene and p53 protein expression were both located in the nuclei. The positive incidences of overexpression of both c-myc gene and p53 protein in PHC were 76% and 55% respectively. The distribution and strength of the overexpression of c-myc gene and p53 protein in PHC are related to the degree of cell differentiation and the overexpression in the liver tissue surrounding the carcinoma is lower than that detected in the PHC tissue.

Carcinoma, Hepatocellular↗
PubMed1993

Aberrations of p53 gene in human hepatocellular carcinoma from China.

Allele losses and mutations have been examined in 38 cases of primary hepatocellular carcinomas (HCC) from different geographic areas of China by Southern, single-strand conformational polymorphism (SSCP) and direct DNA sequencing analyses. Two of 12 samples from Qi-Dong and six of 18 HCCs from Shanghai showed loss of heterozygosity (LOH) at the loci on chromosome 17p13.3. All of the nine mutations in the p53 gene detected in HCC from Qi-Dong were clustered at the third base of codon 249, i.e. G:C to T:A, leading to an arginine to serine change. In contrast, 18 HCC samples from Shanghai contained three mutations at codons 249, 255 and 279. These results suggested a relationship between the spectrum of p53 aberration and environmental risk factors in these two geographic areas. Since no correlation between the state of HBV DNA and p53 aberration was observed, other factors such as dietary exposure to aflatoxin B1 (AFB1) might be responsible for the mutational hotspot at codon 249 in HCCs from Qi-Dong area.

Aflatoxin B1↗
PubMed1992

[Clinical and pathological features of primary hepatocellular carcinoma in 26 patients survived over 10 years after operation].

The clinical and pathological features of primary hepatocellular carcinoma (PHC) in 26 patients who had survived over 10 years after operation were analyzed. The results were as follows: 84.62% (22 patients) were detected by AFP screening, 80.77% (21 patients) were in clinical stage I, 76.96% (20 patients) were younger than 45 years of age. Serum AFP of all patients turned negative within 2 months after operation. The tumor diameters ranged from 1.2 cm to 15 cm, and solitary tumors accounted for 80.77% (21 patients). All tumors were encapsulated and infiltrated by lymphocytes. Cirrhosis was found only in 9 cases (34.62%). The positive rates of HBsAg and HBcAg were 80% and 15% respectively in hepatic tissues surrounding the carcinoma. These results suggest that good prognosis or long survival is related to early detection, younger age of the patient, solitary tumor, better encapsulation, mild injury of the surrounding liver tissues, and rapid negative turning of AFP after operation.

Adolescent↗
PubMed1991

Mutational hotspot in the p53 gene in human hepatocellular carcinomas.

Human hepatocellular carcinomas (HCC) from patients in Qidong, an area of high incidence in China, in which both hepatitis B virus and aflatoxin B1 are risk factors, were analysed for mutations in p53, a putative tumour-suppressor gene. Eight of the 16 HCC had a point mutation at the third base position of codon 249. The G----T transversion in seven HCC DNA samples and the G----C transversion in the other HCC are consistent with mutations caused by aflatoxin B1 in mutagenesis experiments. No mutations were found in exons 5,6,8 or the remainder of exon 7. These results contrast with p53 mutations previously reported in carcinomas and sarcomas of human lung, colon, oesophagus and breast; these are primarily scattered over four of the five evolutionarily conserved domains, which include codon 249 (refs 4-9). We suggest that the mutant p53 protein may be responsible for a selective clonal expansion of hepatocytes during carcinogenesis.

Base Sequence↗
PubMed1989

[Pathologic analysis of primary hepatocellular carcinoma in 19 cases surviving over 10 years].

Pathological study was undertaken in 19 PHC patients who had survived over 10 years after operation. The pathological characteristics of the specimens were as follows: (1) Tumors less than 5 cm in diameter accounted for 78.9% (15/19), of which 13 PHC less than or equal to 3 cm in diameter. (2) Solitary tumors were found in 78.9% (15/19). (3) Sixteen out of nineteen (84.2%) cases had peritumor-fibrous encapsulation, and 13 cases had fibrolamellar structures in cancerous foci. (4) 14 out of 19(73.7%) cases were found to have lympholeukocyte infiltration in cancerous foci or encapsulation. (5) Liver cirrhosis was found in only 42.1% (8/19) of all cases and 75% of them were slight cirrhosis. These were the pathological background accounting for long survival duration of PHC patients. The authors suggest that early detection, diagnosis, and treatment be done in this period, for better opportunity of survival in PHC patients.

Adolescent↗
PubMed1987

Structure determination of kanglemeisu A by X-ray diffraction method.

Kanglemeisu A (C50H63O19B.CH3OH) is the product of an actinomyces species from a soil sample gathered in China Kanglemeisu A belongs to the triclinic system, space group P1, unit cell: a = 12.760(3), b = 10.287(2), c = 9.926(2) A, alpha = 88.39(2), beta = 78.64(2), gamma = 89.14(2). RANTAN direct method is used to solve the structure. The final discrepancy factor is R = 0.0689, after atom coordinates and temperature factors have been refined with full matrix least squares. The structure skeleton consists of four parts, the naphthalene nucleus connected to the 5-membered ring, a 17-membered ring connected to C2, a dimethyl butane diacid extended out from C20, beta-D-3,4-OO' methylenedigitoxose passing through an oxygen bridge O6 and linked to C27 of ansa ring.

Anti-Bacterial Agents↗
PubMed1986

[Fine needle aspiration cytology in the diagnosis of primary liver cancer].

From Dec. 1979 to Dec. 1984, 171 patients suspicious of primary liver cancer (PLC) were examined by fine needle aspiration cytology (FNAC). In this series, 148 patients were finally diagnosed as PLC. By FNAC, 133 of 148 patients showed positive cytology and 4 suspiciously positive cytology. The overall diagnostic accuracy was 92.6% There was no false positive. Neither spreading or bleeding were observed. The results show that FNAC examination, being simple, rapid and safe, could serve as a reliable way of diagnosing the suspected PLC.

Adolescent↗
PubMed1984

Takaokamycin, a new peptide antibiotic produced by Streptomyces sp.

A new peptide antibiotic named takaokamycin was isolated from a fermentation broth of Streptomyces sp. AC-1978, a soil isolate. It exhibits antibacterial activity against some Gram-positive bacteria. The molecular weight was found to be 1,130 on the basis of elemental analysis, FD-mass spectrum and 1H and 13C NMR. Acid hydrolysate of takaokamycin contains isoleucine, threonine and unidentified amino acids.

Animals↗