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Biomedical subjects

R Holland

Publications and source records attributed to R Holland.

At least 19 recordsLinked to original sources
PubMed2000

[Alterations of stage distribution for breast cancer since the implementation of national screening program in the Netherlands during 1989-1995].

OBJECTIVE: To determine the results of the nation-wide breast cancer screening on the basis of the stage distribution of diagnosed breast cancer 1989-1995. DESIGN: Descriptive, inventory. METHOD: At the University of Nijmegen data concerning the numbers of diagnosed breast cancer cases and age and stage at diagnosis were obtained from the Netherlands Cancer Registry for the years 1989-1995. Population data were provided by Statistics Netherlands. With these data incidence figures were calculated. RESULTS: The number of invasive breast cancers rose from almost 8,000 in 1989 to almost 10,500 in 1994. In 1995, a small decrease was visible. The increase was largest in women aged 50-69 years, the target population of the screening programme (introduced in 1988), and less in older women. In women aged 50-69 years, the incidence of stage I tumours doubled, stage II tumours increased but had returned to original levels in 1995, whereas stage III and IV had decreased by more than 24%. The number of carcinomas in situ rose from 336 in 1989 to 829 in 1995 in all age categories, but most in women aged 50-69 years. CONCLUSION: When the implementation scheme of the national screening programme is taken into account, the results are indicative of a reduction in breast cancer mortality. Whether such a mortality reduction actually will follow, has to be awaited.

Adult↗
PubMed2000

Correlation of high-resolution breast MR imaging with histopathology; validation of a technique.

A high-resolution three-dimensional surface gradient coil set was used to obtain magnetic resonance (MR) images of breast specimens, using a gradient-echo pulse sequence (TR/TE 1000/8 msec, flip angle 75 degrees), with 117 micrometer in-plane resolution and 1 mm slice thickness. Breast tissues were obtained from one autopsy and three surgical specimens. High-resolution breast MR images and histopathology sections (7 micrometer thickness) were acquired in the same anatomical plane. Radiographs were acquired of the sliced specimens (approximately 5 mm thick) so that images from all three methods could be correlated. It was found that in vitro high-resolution breast MRI correlated well with low-resolution microscopic histology, demonstrating normal anatomy (lobules, ducts, connective tissue strands, blood vessels) and pathology (tumor content, margins, and presence of microcalcifications) of the breast more clearly than conventional pre-gadolinium breast MRI. High-resolution breast MRI may improve specificity, when added to a conventional breast MRI protocol.

Biopsy↗
PubMed2000

Malignant adenomyoepithelioma of the breast with metastasis in the thyroid gland 12 years after excision of the primary tumor. Case report and review of the literature.

We describe a patient who was admitted to our hospital with an enlarged left lobe of the thyroid gland. Since fine-needle aspiration showed atypical follicular cells, a surgical exploration followed. Owing to extensive tumor infiltration into the surrounding tissues curative surgery was not possible, and only an incisional biopsy was taken. Histological examination of this biopsy revealed a mixed tumor composed of epithelial and myoepithelial cells. A primary thyroid tumor, metastasis of a salivary gland, and a skin appendage tumor could be excluded based on clinical examination, conventional histology, and immunohistochemistry. A tumor of the left breast treated 12 years earlier had originally been classified as an intraductal/intracystic carcinoma with focal invasion, but was re-examined. Using immunohistochemistry, the breast tumor was reclassified as a malignant adenomyoepithelioma. The current tumor was apparently a metastasis from this primary breast tumor. An updated review of the literature is given, including current knowledge on histological and immunohistochemical features of adenomyoepithelioma of the breast, with special attention to the reported pathological characteristics of recurrent and malignant tumors. Based on the reported pathological characteristics of recurrent and metastatic tumors we offer a diagnostic tool for identifying potentially malignant and recurrent tumors.

Biomarkers, Tumor↗
PubMed2000

Parity and mammographic breast density in relation to breast cancer risk: indication of interaction.

We examined whether the harmful influence of nulliparity on breast cancer risk could be mediated by high mammographic density. Another possibility is that mammographic density and nulliparity act independently or perhaps synergistically on breast cancer risk. Our study population consisted of 129 cases and 517 controls who had been participants in the Nijmegen breast cancer screening programme for 10 years. Breast density was classified with a fully automated technique on digitized mammograms from the screening examination 10 years before diagnosis. Classification was based on the proportion of the breast that was composed of high density: < 5%, 5-25% or > 25%. Data on parity and potential confounders were obtained using a questionnaire, administered at the same examination. We found that nulliparae with low breast density (< 5%) were not at increased risk compared to parous women with low density: OR 1.1 (95% CI 0.2-5.8). Parous women with < 5% density formed the reference category throughout all analyses. The risks for parous women with 5-25% or > 25% density were 2.7 (95% CI 1.3-5.6) and 3.6 (95% CI 1.7-7.7) fold increased, respectively. However, when both factors were present (nulliparity and > or = 5% density), breast cancer risk was 7.1 times higher (95% CI 3.2-15.9). This could indicate that nulliparity and high breast density might work synergistically and that breast density is not just an explanatory factor in the influence of nulliparity on breast cancer risk. It is hypothesized that high breast density (reflecting fibro-glandular tissue with increased epithelial cell proliferation) is more susceptible to carcinogenic effects in the undifferentiated epithelial breast tissue of nulliparae than in the differentiated tissue of parous women. Since there were few data, no firm conclusions can be drawn. If these findings can be confirmed in a larger study population, however, they may have important implications for the prevention and early detection of breast cancer.

Adult↗
PubMed2000

Cloning, characterization, controlled overexpression, and inactivation of the major tributyrin esterase gene of Lactococcus lactis.

The gene encoding the major intracellular tributyrin esterase of Lactococcus lactis was cloned using degenerate DNA probes based on 19 known N-terminal amino acid residues of the purified enzyme. The gene, named estA, was sequenced and found to encode a protein of 258 amino acid residues. The transcription start site was mapped 233 nucleotides upstream of the start codon, and a canonical promoter sequence was identified. The deduced amino acid sequence of the estA product contained the typical GXSXG motif found in most lipases and esterases. The protein was overproduced up to 170-fold in L. lactis by use of the nisin-controlled expression system recently developed for lactic acid bacteria. The estA gene was inactivated by chromosomal integration of a temperature-sensitive integration vector. This resulted in the complete loss of esterase activity, which could then be recovered after complementation of the constructed esterase-deficient strain with the wild-type estA gene. This confirms that EstA is the main enzyme responsible for esterase activity in L. lactis. Purified recombinant enzyme showed a preference for short-chain acyl esters, surprisingly also including phospholipids. Medium- and long-acyl-chain lipids were also hydrolyzed, albeit less efficiently. Intermediate characteristics between esterases and lipases make intracellular lactococcal EstA difficult to classify in either of these two groups of esterolytic enzymes. We suggest that, in vivo, EstA could be involved in (phospho)lipid metabolism or cellular detoxification or both, as its sequence showed significant similarity to S-formylglutathione hydrolase (FGH) of Paracoccus denitrificans and human EstD (or FGH), which are part of a universal formaldehyde detoxification pathway.

Amino Acid Sequence↗
PubMed2000

Tracking clock-shifted homing pigeons from familiar release sites.

Clock-shifted homing pigeons were tracked from familiar sites 17.1 km and 23.5 km from the home loft in Pisa, Italy, using an on-board route recorder. At the first release site, north of home, the majority of clock-shifted birds had relatively straight tracks comparable with those of control birds. At the second release site, south of home, the clock-shifted birds deflected in the direction predicted for the degree of clock shift, with many birds travelling some distance in the wrong direction before correcting their course. The possible role of large-scale terrain features in homing pigeon navigation is discussed.

Animals↗
PubMed1999

An outbreak of Salmonella typhimurium RDNC A045 at a wedding feast in South Australia.

In April 1998 an outbreak of salmonellosis amongst guests at a wedding feast was investigated. Of the 58 attendees interviewed 38 (66%) subsequently developed gastrointestinal symptoms. Stool cultures from 7 cases grew Salmonella Typhimurium RDNC A045. Food samples were culture-negative for Salmonella spp. A cohort study implicated spatchcock (RR 2.5, 95% CI 1.09-5.77) and scampi (RR 2.0, 95% CI 1.05-3.89). Temperature abuse and cross-contamination within the kitchen during preparation and cooking are likely to have been the main contributing factors to this outbreak. Control measures included staff education in safe food handling and improvements in poultry processing methods to minimise carcass contamination.

Cohort Studies↗
PubMed1999

Reaction of dogs' teeth to root canal filling with mineral trioxide aggregate or a glass ionomer sealer.

This study was conducted to observe the reaction of apical tissues of dogs' teeth after root canal filling with gutta-percha and mineral trioxide aggregate (MTA) or a glass ionomer (Ketac-Endo) as a sealer. The root canals were instrumented and filled by the lateral condensation technique with the sealers studied. Animals were killed 6 months later, and the specimens were removed and prepared for histological analysis. Results showed no inflammatory reaction of apical tissue and total closure of the apical foramen of all the teeth sealed with MTA. The teeth sealed with Ketac-Endo showed two cases of partial closure and different degrees of chronic inflammatory reaction. In conclusion, MTA exhibited better biological properties than Ketac-Endo.

Aluminum Compounds↗
PubMed1999

Reaction of rat connective tissue to implanted dentin tubes filled with mineral trioxide aggregate or calcium hydroxide.

This study was conducted to observe the rat subcutaneous connective tissue reaction to the implanted dentin tubes filled with calcium hydroxide or mineral trioxide aggregate. The animals were sacrificed after 7 and 30 days, and the specimens were prepared for morphological study. Some undecalcified specimens were prepared for histological analysis with polarized light and Von Kossa technique for calcium. The results were similar for both studied materials. At the tube openings, there were Von Kossa-positive granules that were birefringent to polarized light. Next to these granulations, there was an irregular tissue like a bridge that was Von Kossa-positive. The dentin walls of the tubes exhibited in the tubules a structure highly birefringent to polarized light, usually like a layer and at different depths. It is possible that the mechanism of action of both materials has some similarity.

Aluminum Compounds↗
PubMed1999

Changes in mammographic breast density and concomitant changes in breast cancer risk.

Among participants of the biennial Nijmegen breast cancer screening programme, we examined whether diminution of mammographic breast density lowered breast cancer risk. Post-menopausal breast cancer cases (n = 108), who had to have participated in all the five screening rounds prior to their diagnosis, were matched to 400 controls on year of birth and screening history. Controls had to be free of breast cancer at the time of the case's diagnosis. Changes in breast density were measured over a 10-year period, by a fully computerized method. Women in whom 5-25% or >25% of the breast was composed of fibro-glandular density showed a threefold increased 10-year risk compared to women with <5% density. In women with 5-25% density initially, we observed a trend of decreasing risk with diminishing density: when women with <5% density throughout the whole period formed the reference category, the odds ratio (OR) for those who decreased from 5-25% to <5% density was 1.9 [95% confidence interval (CI) = 0.6-6.1] in contrast to the OR of 5.7 (95% CI = 2.2-15.2) for those with persisting 5-25% density. In women who increased from 5-25% density to >25% density the OR was 6.9 (95% CI = 2.1-22.9). In women with >25% density initially, diminishing density was not clearly associated with lowering risk, which may be partly explained by the low number of women who decreased to <5% (n = 12). Due to the limited size of the study these results have to be interpreted with caution. Although the results are not conclusive, they could indicate a trend of decreasing risk with diminishing breast density. Should this effect be real, it may have great implications for the primary prevention of breast cancer or for the identification of high-risk groups who would benefit by more frequent screening. Therefore, large-scale, long-term follow-up studies on the effects of changes in breast density are needed.

Adult↗
PubMed1999

High mammographic breast density and its implications for the early detection of breast cancer.

OBJECTIVES: Women with high mammographic breast density are at increased risk of breast cancer. This study explores whether these women should receive intensified screening (more frequent screening or screening with alternative techniques that increase the length of the preclinical detectable phase) to reduce further breast cancer mortality. METHODS: Mathematical models were used to estimate the effects of intensified screening in women with high breast density. The effects were expressed as a reduction in the number of interval cancers. RESULTS: If women with > 25% breast density (comprising about one fifth of all women) are screened annually instead of biennially, an 18% reduction in the total number of interval cancers can be expected. Screening these women with alternative screening techniques biennially may produce the same reduction, provided that these techniques double the mean lead time. CONCLUSIONS: By screening women with dense breasts more intensively, many more breast cancers can theoretically be detected at an early stage. The results provide an early indication of what may be expected from screening strategies. Next, cost-benefit analyses are needed.

Breast Neoplasms↗
PubMed1998

Electropotential measurements as a new diagnostic modality for breast cancer.

BACKGROUND: Proliferative changes in breast epithelium are an intrinsic aspect in the development of breast cancer, and result in regions of epithelial electrical depolarisation within the breast parenchyma, which can extend to the skin surface. Diagnostic information might be obtained from a non-imaging and non-invasive test based on skin-surface electropotentials. METHODS: In 661 women, scheduled for open biopsy at eight European centres, we studied whether measurements of breast electrical activity with surface sensors could distinguish benign from malignant breast disease. A depolarisation index was developed. RESULTS: We found a highly significant trend of progressive electrical changes according to the proliferative characteristics of the biopsied tissue. Discriminatory information was obtained in both premenopausal and postmenopausal women, and the index was not related to age. The best test performances were for women with palpable lesions. The median index was 0.398 for non-proliferative benign lesions, 0.531 for proliferative benign lesions, and 0.644 for cancer (ductal carcinoma-in-situ and invasive). A specificity of 55% was obtained at 90% sensitivity for women with palpable lesions when a discriminant based on age and the depolarisation index was used. INTERPRETATION: This new modality may have diagnostic value, especially in reducing the number of unnecessary diagnostic tests among women with inconclusive findings on physical examination. Understanding and control of the biological variability of these electrical phenomena will be important in the improvement of this test. Studies in populations with a lower cancer prevalence are needed to assess further the diagnostic value of this approach.

Adolescent↗
PubMed1998

Characterisation of benign lesions and carcinomas of the female breast in a sub-Saharan African population.

Carcinoma of the breast is the second most frequent tumour in African females. Breast carcinomas in African females appear about a decade earlier and follow a more aggressive clinical course than those in developed countries. To elucidate this difference we investigated 63 biopsied benign lesions of the female breast for their potential to malignant progression. We also performed histologic typing and grading of 184 female breast carcinomas received at the Muhimbili University Hospital in Dar es Salaam, Tanzania. Fibrocystic disease and fibroadenomas were the most frequent lesions. The majority of patients with fibrocystic disease had no proliferative lesion and thus were not at a significantly increased risk of developing breast carcinomas. For fibroadenomas, no indication for precancerous lesions was found. The vast majority of breast carcinomas investigated were invasive. As a striking feature, the majority of those studied (66%) were of the non-special type (NST), displaying a more aggressive behaviour than the remaining tumours of the special type (ST). In the group of ST tumours, cribriform types constituted 41% of the cases which may be a special feature of the carcinomas in African females. Among the NST, the tumours were either of grade II or grade III, whereas in ST, 25% of the cases were of grade I. Since histology observed in this study is comparable to that seen in patients from the Western society, late hospital presentation with advanced tumour stages may be a major reason for differences in clinical behaviour between African and Western females. A genetic factor, however, may be an important contributing factor.

Africa South of the Sahara↗
PubMed1998

Effect of root canal filling material and level of surgical injury on periodontal healing in dogs.

Some divergencies in the literature about periodontal healing after surgical injury stimulated the development of this experiment. The root canals of dogs' teeth were negotiated and filled by the lateral condensation technique with two kinds of sealers: Sealapex and zinc oxide-eugenol cement. In the second session, the bone tissue was exposed and one cavity was made at the apical third of the root and another at the border between the coronal and middle thirds, both penetrating into the root canal. Six months later the animals were sacrificed and the specimens prepared for histopathologic analysis. The results showed that the kind of filling material and the level of the periodontal wound exposing the root canal can influence the healing process.

Animals↗
PubMed1998

Influence of reduced water activity on lactose metabolism by lactococcus lactis subsp. cremoris At different pH values

The influence of reduced water activity (aw) on lactose metabolism by Lactococcus lactis subsp. cremoris 2254 and 2272 was studied at different pH values. In control incubations (aw, 0.99) with nongrowing cells in pH-controlled phosphate buffer, the levels of carbon recovered as L-(+)-lactate were 92% at pH 6.1 and 5.3 and 78% at pH 4.5. However, the levels of recovery decreased to approximately 50% at all pH values tested when the aw was 0.88 (with glycerol as the humectant). When growing cells in broth controlled at pH 6.3 were used, a reduction in the aw from 0.99 to 0.96 resulted in a decrease in the level of lactose carbon recovered as L-(+)-lactate from 100 to 71%. Low levels of L-(+)-lactate carbon recovery (<50%) were also observed with cells resuspended in pH-uncontrolled reconstituted skim milk at aw values of 0.99 and 0. 87 and in young cheese curds. The missing lactose carbon could not be accounted for by acetate, ethanol, formate, acetaldehyde, or pyruvate. Attempts were made to determine where the missing lactose carbon was diverted to under the stress conditions used. Some of the missing lactose carbon was recovered as galactose (0.1 to 2.5 mM) in culture supernatants. Decreasing either the aw or the pH resulted in increased galactose accumulation by nongrowing cells; adjusting both environmental factors together potentiated the effect. The sensitivities of the two lactococcal strains tested were different; strain 2272 was more prone to accumulate galactose under stress conditions. A methyl pentose(s) and additional galactose were found in acid-hydrolyzed supernatants from cultures containing both growing and nongrowing cells, indicating that a saccharide(s) rich in these components was formed by lactococci under low-aw and low-pH stress conditions.

Journal Article↗
PubMed1998

Effect of mammographic breast density on breast cancer screening performance: a study in Nijmegen, The Netherlands.

STUDY OBJECTIVE: To study the implications of breast density on mammographic screening performance. DESIGN: Screening outcomes of women with dense breast patterns were compared with those of women with lucent breast patterns (dense > 25% densities, lucent < or = 25% densities); the women were screened in different periods (before/after improvement of the mammographic technique in 1982). SETTING: Nijmegen, the Netherlands, 1977-1994. PARTICIPANTS: Between 1977 and 1994, 73,525 repeat screenings were performed in 19,152 participants (aged 50-69 years) in the Nijmegen breast cancer screening programme (repeat screenings were defined as mammographic examinations that were preceded by an examination in the previous screening round). Participants were screened biennially with mammography. There were 258 screen detected and 145 interval cancers. MAIN RESULTS: Before 1982 (rounds 2-4) the predictive value of a positive screening test (PV+) was lower in women with dense breasts than in those with lucent breasts (dense 29% v lucent 52%, p = 0.003). Also, the ratio of screen detected cancers to the total number of screen detected plus interval cancers (as a proxy for sensitivity) was lower in this group (based on a one year interval: dense 63% v lucent 92%, p = 0.001 and based on a two year interval: dense 41% v lucent 68%, p = 0.002). Moreover, the survival rate was less favourable for those with dense breasts (p = 0.07). In rounds 5-10, there were no important differences with respect to PV+ (dense 66% v lucent 62%, p = 0.57) or survival (p = 0.48). Moreover, sensitivity based on a one year interval was nearly as high in women with dense breasts as in those with lucent breasts (85% v 86%, p = 0.75). However, based on a two year interval sensitivity was lower (dense 59% v lucent 72%, p = 0.04). CONCLUSIONS: In the early screening years (rounds 2-4) high breast density had an unfavourable effect on screening performance. Nowadays, the situation has improved with respect to PV+, survival and detecting tumours in dense breasts with a lead time of up to one year, but little improvement has occurred in the detection of tumours with a lead time greater than one year.

Aged↗
PubMed1998

Calcium hydroxide and a corticosteroid-antibiotic association as dressings in cases of biopulpectomy. A comparative study in dogs' teeth.

The subject of this paper was to study the behavior of the periapical tissues of dogs' teeth after biopulpectomy and dressing with calcium hydroxide or a corticosteroid-antibiotic association, before root canal filling with zinc oxide eugenol (ZOE) or Sealapex sealers. The teeth were overinstrumented and dressed for 7 days before the root canal filling. The animals were sacrificed 180 days after treatment and the specimens were prepared for morphological analysis. Specimens treated with Sealapex presented a higher number of cases with biological closure than ZOE. When the root canals were filled with ZOE, better results were observed with the use of the Ca(OH)2 dressing.

Animals↗