Biomedical subjects

S Lundgren

Publications and source records attributed to S Lundgren.

At least 19 recordsLinked to original sources

PubMed2006

Clinical 1H magnetic resonance spectroscopy of brain metastases at 1.5T and 3T.

PURPOSE: To investigate whether improvements in signal-to-noise ratio (SNR) and spectral resolution are found in spectra from patients with brain metastases obtained at higher magnetic field strengths using standard clinical instrumentation. MATERIAL AND METHODS: Six patients with brain metastases, 13 healthy volunteers, and a phantom containing brain metabolites were examined using two clinical MR instruments operating at 1.5T (Siemens) and 3T (Philips) with standard clinical head coils. Spectra were obtained using a point resolved spectroscopy pulse sequence, echo times (TE) 32 ms and 144 ms, and repetition time 2000 ms from a volume-of-interest (VOI) of size 15 x 15 x 15 mm3. SNR and spectral resolution of the metabolites N-acetylaspartate, choline, and creatine compounds in spectra from 3T were compared to the 1.5T spectra. RESULTS: In general, spectral resolution was improved by 25-30% at higher magnetic field strength. Only minor improvements in SNR were obtained at 3T using short echo time and 20-50% at long echo time. CONCLUSION: SNR and spectral resolution were improved at higher magnetic field strength, especially with TE 144 ms, including spectra from patients with heterogeneous brain tumors. However, differences in the defined effective VOI, particularly at short echo time, reduced the expected effect of increased magnetic field strength on the measured SNR.

Adult↗

PubMed2005

Monitoring of implant stability in grafted bone using resonance frequency analysis. A clinical study from implant placement to 6 months of loading.

The aim of this prospective study was to compare implants placed in grafted and normal non-grafted maxilla by means of resonance frequency analysis (RFA), clinical stability and implant failure. Twenty-nine patients with severe atrophy of the edentulous maxilla were treated with autogenous bone grafts as onlay (24 patients) or as interpositional grafts in conjunction with a Le Fort I osteotomy (five patients) 6 months prior to placement of 222 implants. Ten non-grafted patients treated with 75 Brånemark implants in the edentulous maxillae served as a control group. RFA was performed at implant placement, abutment connection and after 6 months of bridge loading. Seventeen (8%) implants were lost in the grafted bone and one (1%) in normal bone. RFA revealed a similar pattern in both grafted and normal maxillae, i.e. increasing resonance frequency (RF) with time (Wilcoxon Signed Rank test for paired data). Twenty implants that were rotation mobile (low primary stability) at the time of insertion showed a significantly lower value at implant placement according to RFA (Mann-Whitney U-test, P = 0.020). The RF for the failed implants revealed a tendency towards lower values (Mann-Whitney U-test, P = 0.072), compared to the successful implants. It is concluded that implants placed in grafted bone when using a two-stage technique achieve a stability similar to that of implants placed in normal non-grafted bone.

Aged↗

PubMed2005

A 3-year prospective follow-up study of implant-supported fixed prostheses in patients subjected to maxillary sinus floor augmentation with a 80:20 mixture of deproteinized bovine bone and autogenous bone Clinical, radiographic and resonance frequency analysis.

The purpose of this prospective clinical study was to evaluate the 3-year outcome of 30 maxillary sinus floor augmentations with an autogenous bone-deproteinized bovine bone mixture (20:80). A total of 108 dental implants were placed after 6 months of graft healing. After another 6 months, the occlusion was restored with fixed prostheses and followed for 3 years of functional loading. Clinical and radiographic examinations of the sinuses and implants, including computerized tomography (CT) were performed. The stability of the implants was evaluated by means of resonance frequency analyses (RFA). After 3 years of functional loading with fixed bridges, 15 of 108 implants were lost giving a cumulative survival rate (CSR) of 86%. All followed patients, except one, had fixed bridges in function after 3 years of loading. The mean marginal bone loss was 1.3+/-1.1 mm after 3 years. RFA showed a mean implant stability quotient (ISQ) value of 66+/-4.1 after 3 years with no significant difference between implants in grafted and residual bone. Examination with CT showed that 67% of the maxillary sinuses were healthy prior to treatment and 71% after 3 years of loading. It was concluded that grafting of the maxillary sinus with a mixture of autogenous bone and deproteinized bovine bone is a reliable procedure.

Aged↗

PubMed2005

Cyclophosphamide induces mRNA, protein and enzyme activity of cytochrome P450 in rat.

The effects of cyclophosphamide (CPA) on CYP enzymes in vivo and its auto induction in rat were investigated in Wistar/Fu male rats at a single dose (40 or 200 mg kg(-1)) or as repeated dose of 200 mg kg(-1) CPA. After a single dose of CPA, mRNAs of CYPs 2B1, 2B2, 3A2, 2C11 were significantly induced up to 220-, 6.7-, 5.0- and 5.8-fold at the low dose CPA, and 4800-, 52-, 22- and 2.5-fold at the high dose. CYP2B1/2 and CYP3A proteins were increased by 4- and 2-fold (low dose) and by 28- and 1.7-fold (high dose). CYP2C11 protein levels were not altered. Microsomal activities of CYP2B, CYP3A and 2C11 were increased by 2-, 1.8- and 1.3-fold at low dose CPA, and 3.2-, 1.7- and 1.6-fold at high dose. A significant (p<0.05) decrease in CPA concentration and a significant (p<0.05) increase in 4-OH-CPA levels were observed with repeated administration of CPA. Acute induction effect on CYP2B1, 2B2, 2C11 and 3A2 and a substantial up regulation of CYP2B1 mRNA were observed after a single dose of CPA, auto induction was observed by repeated administration.

Animals↗

PubMed2003

Alteration of pharmacokinetics of cyclophosphamide and suppression of the cytochrome p450 genes by ciprofloxacin.

Recently, it has been reported that prophylactic administration of ciprofloxacin during cyclophosphamide (CY) conditioning was a high-risk factor for relapse in patients undergoing allogeneic BMT. In the present study, we investigated the possible mechanisms of this interaction in male Sprague-Dawley rats. The kinetics of CY and its active 4-OH-CY metabolite were determined, after 3 days pretreatment with ciprofloxacin (200 mg/kg) and compared to control rats without treatment. CY was administered as a high or low single intravenous dose (150 and 90 mg/kg, respectively). The expression of the CYP2B1, CYP2B2, CYP2C11, CYP3A1 and CYP3A2 genes was evaluated by SYBR Green I Dye real-time PCR for quantification of mRNA. The administration of ciprofloxacin resulted in a significant increase in the AUC (P=0.007) and a significant decrease in clearance (P=0.007) when CY was given as a high dose. In accordance, the metabolic ratio (AUC4-OH-CY/AUCCY) was significantly lower (P=0.007) compared to that found in the control group. Ciprofloxacin significantly suppressed gene expression of CYP2C11 (P=0.01) and CYP3A1 (P=0.04); however, no effect was observed on the gene expression of CYP3A2, CYP2B1 and CYP2B2. Our study revealed that ciprofloxacin interacts with CY and suppressed relevant cytochromes p450 at the transcriptional level. This study may have a great clinical impact when ciprofloxacin is used in therapy.

Animals↗

PubMed2003

Role of polymorphic human CYP2B6 in cyclophosphamide bioactivation.

The role of polymorphic CYP2B6 in cyclophosphamide (CPA) bioactivation was investigated in human liver microsomes. A total of 67 human liver specimens were first genotyped with respect to the CYP2B6*5 and CYP2B6*6 variant alleles. CYP2B6 apoprotein levels in 55 liver microsomal preparations were assessed by immunoblotting. 4-Hydroxy-CPA and hydroxy-bupropion were quantified by using HPLC and LC-MS, respectively. 7-Ethoxy-4-trifluoromethyl coumarin O-deethylase activity was measured fluorometrically. The frequencies of CYP2B6*5 and CYP2B6*6 mutant alleles were 9.0 and 16.4%, respectively. CYP2B6 protein expression was detected in 80% of the samples, with a large variation (0.003-2.234, arbitrary units). There was a high correlation between CYP2B6 apoprotein content and CPA 4-hydroxylation (n=55, r=0.81, P<0.0001). When based on the CYP2B6 apoprotein levels, the *6 carriers had significantly higher CPA 4-hydroxylation (P<0.05). CPA 4-hydroxylation also correlated significantly with other CYP2B6-specific reactions (n=20, P<0.0001). V(max) and K(m) for CPA 4-hydroxylation in recombinant CYP2B6 enzyme were 338 nmol/min/nmol enzyme and 1.4 mM, respectively. CYP2B6 showed much higher in vitro intrinsic clearance than previously observed in recombinant CYP2C19 and CYP2C9 variants in yeast expression system. Our results demonstrate that the polymorphic CYP2B6 is a major enzyme in the bioactivation of CPA. Moreover, we identified a strong impact of CYP2B6*6 on CPA 4-hydroxylation.

Analysis of Variance↗

PubMed2001

[Breast cancer surgery in Norway 1990-95 illustrated by data from SINTEF United].

BACKGROUND: Breast-conserving therapy has been shown to be as effective as mastectomy in many cases; hence in many countries more breast cancer patients are offered this type of treatment. This study focuses on the amount and type of surgery used in Norway for breast cancer patients and the possible use of hospital discharge data to evaluate the diffusion of this surgical practice. MATERIAL AND METHODS: Data from the nationwide Register of Hospital Discharges in Norway at SINTEF Unimed for patients operated for breast cancer from 1990 to 1995 were used. RESULTS: 11,041 patients were registered with 11,727 hospital admissions for breast cancer operations from a total of 64 hospitals. The discrepancy in the number of breast cancer patients with the National Cancer Registry was 7%. Breast-conserving surgery was performed in 19.7%. An increase from 17% in 1990 to 21% in 1995 was found, but with variations according to type of hospital, county and age of patients. INTERPRETATION: The percentage of breast conserving surgery is still low in Norway; this indicates that many women are not offered this type of surgery. With some caution, the data from SINTEF Unimed can be used to reflect the clinical practice over time at Norwegian hospitals. Further improvements could be obtained if national identity numbers were added to the database.

Adult↗

PubMed2001

Caffeine metabolism and the risk of spontaneous abortion of normal karyotype fetuses.

OBJECTIVE: To investigate whether the rate of caffeine metabolism influences spontaneous abortion risk. METHODS: We studied 101 women with normal karyotype spontaneous abortions and 953 pregnant women at 6-12 gestational weeks. Participants reported on caffeine intake and provided urine for phenotyping cytochrome P4501A2 (CYP1A2) activity and blood for genotyping N-acetylation (NAT2) status. We calculated odds ratios (OR) and 95% confidence intervals (CI) to evaluate the association between each of the two metabolic indices and spontaneous abortion risk and also the potential interaction between caffeine intake and metabolic activity on such risk. In calculating the associations between the metabolic indices and risk of spontaneous abortion, we had 80% power to detect an OR of 2.1, with a Type I error of 0.05. RESULTS: Slow acetylators had a nonsignificantly increased risk for spontaneous abortion (OR 1.36, 95% CI 0.84, 2.21) and recurrent spontaneous abortion (OR 2.51, 95% CI 0.81, 7.76). In contrast, low CYP1A2 activity was associated with a significantly decreased risk for spontaneous abortion (OR 0.35, 95% CI 0.20, 0.63). Caffeine was a risk factor for spontaneous abortion among women with high, but not low, CYP1A2 activity (OR 2.42, 95% CI 1.01, 5.80 for 100-299 mg/day; OR 3.17, 95% CI 1.22, 8.22 for 300 mg/day or more, among women with high CYP1A2 activity). CONCLUSION: The findings indicate that high CYP1A2 activity may increase the risk of spontaneous abortion, independently or by modifying the effect of caffeine. The results regarding NAT2 are less conclusive but suggest that slow acetylators may be at elevated risk of spontaneous abortion.

Abortion, Spontaneous↗

PubMed2001

A clinical histologic study of bovine hydroxyapatite in combination with autogenous bone and fibrin glue for maxillary sinus floor augmentation. Results after 6 to 8 months of healing.

Biopsies were taken from 16 out of 20 consecutive referral patients 6 to 8 months after maxillary sinus floor augmentation with a mixture of bovine hydroxyapatite (BH), autogenous bone particles and fibrin glue. Four days prior to biopsy retrieval the patients were given a single dose of tetracycline to label bone forming sites. Fluorescence microscopy of 100 microm thick sections revealed active bone formation in conjunction with the BH particles in 14 of 15 specimens analysed. Light microscopy and morphometry of ground sections from 16 patients showed various amounts of mineralised bone tissue in all except one specimen. In the latter case, the BH particles were encapsulated by a dense fibrous connective tissue. Sections from the augmented areas were occupied by non-mineralized tissue (54.1+12.6%), lamellar bone (21.2+24.5%), BH particles (14.5+10.3%) and woven bone (10.2+13.4%). The non-mineralized tissue seen in bone forming areas consisted of a loose connective tissue, rich of vessels and cells, and in the periphery of a more dense fibrous connective tissue. Woven bone with large and scattered osteocyte lacunae was bridging between the BH particles and the lamellar trabecular bone. There were no signs of resorption of the BH particles. The lamellar bone appeared to have originated from the recipient site and was seldom in contact with the BH particles. It is concluded that the tested implant material has bone conducting properties. The bone associated with the BH particles after 6 to 8 months of healing was mainly woven.

Aged↗

PubMed2001

Nurses' use of time in a medical-surgical ward with all-RN staffing.

AIMS: To investigate allocation of nursing time, organisation of nursing activities and whether or not allocation and organisation have changed over time. BACKGROUND: In a ward that changed to all-RN staffing, the nurses were encouraged to implement a patient-focused philosophy. The nurses perceived that they had difficulty in using the time available efficiently. METHODS: Non-participant observations were conducted with 2-year intervals. Ten consecutive weekdays were covered on two occasions. The study was carried out at a university hospital in Sweden. FINDINGS: Between observations, a significant change in the organization of the direct care had occurred, and the same tendency was found in patient administration and general management. The organization of work changed from a partly fragmented to a more coherent one. The time used for direct care and administrative activities increased between the two observations, while indirect care, personal and service activities decreased. CONCLUSION: It can be suggested that the nurses used their time efficiently and, over time, they developed a more coherent way of organizing nursing activities.

General Surgery↗

PubMed2001

Histologic analysis of clinical biopsies taken 6 months and 3 years after maxillary sinus floor augmentation with 80% bovine hydroxyapatite and 20% autogenous bone mixed with fibrin glue.

BACKGROUND: Bovine hydroxyapatite (Bio-Oss, Geistlich Pharmaceutical, Wollhausen, Switzerland) has been suggested to be used in maxillary sinus floor augmentation procedures prior to or in conjunction with implant placement. However, the long-term histologic fate of this material is not well understood. PURPOSE: The aim with this study was to histologically evaluate the tissue response in patients to a mixture of bovine hydroxyapatite (BH), autogenous bone, and fibrin glue 6 months and 3 years after a maxillary sinus floor augmentation procedure. MATERIALS AND METHOD: Biopsies were taken from a group of 20 consecutive patients 6 months (n = 16) and 3 years (n = 12) after maxillary sinus floor augmentation with a mixture of BH (80%), autogenous bone (20%), and fibrin glue and prepared for histologic analysis. RESULTS: Light microscopy and morphometry from biopsies taken after 6 months showed various amounts of mineralized bone tissue. The specimen area was occupied by 54.1 +/- 12.6% nonmineralized tissue, followed by 21.2 +/- 24.5% lamellar bone, 14.5 +/- 10.3% BH particles, and 10.2 +/- 13.4% woven bone. The nonmineralized tissue seen in bone-forming areas consisted of a loose connective tissue, rich with vessels and cells. There were no signs of resorption of the BH particles. The lamellar bone appeared to have originated from the recipient site and was seldom in contact with the BH particles. After 3 years, the nonmineralized tissue area had decreased to 36.0 +/- 19.0% (p < .05) and consisted mainly of bone marrow tissue. The surface area of lamellar bone had increased to 50.7 +/- 22.8% (p < .05), and there was almost no immature bone. The mean specimen area occupied by BH particles, was 12.4 +/- 8.7% and had not changed from 6 months (not significant). Moreover, the sizes of the particles were similar after 6 months and 3 years. The degree of BH particle-bone contact had increased from 28.8% +/- 19.9% after 6 months to 54.5 +/- 28.8% after 3 years (p < .05). CONCLUSION: Histology of specimens from maxillary sinuses augmented with 80% BH particles, 20% autogenous bone, and fibrin glue showed a positive bone tissue response after 6 months and 3 years after augmentation of the maxillary sinus floor prior to implant placement in a group fo 20 patients. The bone surrounding and in contact with the BH particles after 6 months was mainly immature woven bone, which with time was replaced by mature lamellar bone filling the interparticle space as observed in the 3-year specimens. Moreover, bone-integrated BH particles seem to be resistant to resorption. The results indicate that the procedure may be considered when only small amounts of intraoral autogenous bone graft are available.

Aged↗

PubMed2000

Axillary lymph node metastases in breast cancer: preoperative detection with dynamic contrast-enhanced MRI.

Metastatic involvement of axillary lymph nodes is one of the most important prognostic variables in breast cancer. The aim of our work was to study the value of dynamic contrast-enhanced MR imaging in revealing axillary lymph node metastases from breast cancer. A total of 65 patients with invasive breast cancer treated with axillary lymph node dissection were preoperatively evaluated by MRI. T1-weighted dynamic contrast-enhanced 3D images were acquired using a coil covering the breast and the axilla. The dynamic contrast enhancement, size, and morphology of the axillary lymph nodes were registered. Histopathological examination revealed axillary lymph node metastases in 24 patients. When using a signal intensity increase in the lymph nodes of >100% during the first postcontrast image as a threshold for malignancy, 57 of 65 patients were correctly classified (sensitivity 83%, specificity 90%, accuracy 88%). These results were not improved when lymph node size and morphology were used as additional criteria. Axillary lymph nodes can be evaluated as a part of an MR-mammography study without substantial increase in examination time, and provide the surgeon with knowledge about the localization of possible metastatic lymph nodes.

Adult↗

PubMed2000

Breast lesions: evaluation with dynamic contrast-enhanced T1-weighted MR imaging and with T2*-weighted first-pass perfusion MR imaging.

PURPOSE: To evaluate the diagnostic value of an imaging protocol that combines dynamic contrast-enhanced T1-weighted magnetic resonance (MR) imaging and T2*-weighted first-pass perfusion imaging in patients with breast tumors and to determine if T2*-weighted imaging can provide additional diagnostic information to that obtained with T1-weighted imaging. MATERIALS AND METHODS: One hundred thirty patients with breast tumors underwent MR imaging with dynamic contrast-enhanced T1-weighted imaging of the entire breast, which was followed immediately with single-section, T2*-weighted imaging of the tumor. RESULTS: With T2*-weighted perfusion imaging, 57 of 72 carcinomas but only four of 58 benign lesions had a signal intensity loss of 20% or more during the first pass, for a sensitivity of 79% and a specificity of 93%. With dynamic contrast-enhanced T1-weighted imaging, 64 carcinomas and 19 benign lesions showed a signal intensity increase of 90% or more in the first image obtained after the administration of contrast material, for a sensitivity of 89% and a specificity of 67%. CONCLUSION: T2*-weighted first-pass perfusion imaging can help differentiate between benign and malignant breast lesions with a high level of specificity. The combination of T1-weighted and T2*-weighted imaging is feasible in a single patient examination and may improve breast MR imaging.

Adult↗

PubMed1999

Prognostic value of plasma prostate specific antigen after megestrol acetate treatment in patients with metastatic breast carcinoma.

BACKGROUND: Prostate specific antigen (PSA) is an established tumor marker of prostate adenocarcinoma that recently also was found in breast tumors. Minute amounts of PSA are found in female plasma. It is known from cell culture studies that PSA expression can be up-regulated by androgens and progestins but not estrogens. In this study, the authors examined whether plasma PSA in women with breast carcinoma changes after the therapeutic administration of the progestin megestrol acetate (MA) and whether these changes have any prognostic value. METHODS: Plasma PSA was measured by a highly sensitive immunofluorometric procedure that can measure within 1 ng/L of PSA. Serial plasma levels from women with metastatic breast carcinoma who received either MA (N = 52) or other treatments (N = 24) were evaluated. PSA changes in plasma were correlated with patient outcomes. RESULTS: The study found that approximately 50% of the patients receiving MA had a significant increase in their plasma PSA concentration after the treatment and that this increase was rapid (starting within 1 week) and dose-dependent. PSA levels declined when treatment was withdrawn. Further comparisons with similar groups of patients receiving tamoxifen or doxorubicin have shown that the plasma PSA increases are specific to the MA treatment. The plasma PSA increases reflect the stimulation of the tumor by MA to produce PSA and the secretion of PSA into the general circulation. There is a statistically significant association between the plasma PSA changes after MA treatment and overall patient survival; patients with increased plasma PSA have an approximate threefold increase in their relative risk of death during the follow-up period. Multivariate analysis has shown that the increased risk of death in this group is associated, at least in part, with the frequent presence of distant metastasis. CONCLUSIONS: The measurement of plasma PSA after treatment with MA allows for patient classification into two groups. The group that did not demonstrate any changes in their plasma PSA level after MA treatment (approximately 50% of the patients) had a significantly better prognosis. The group that did demonstrate an increase in their plasma PSA level after MA treatment represented a subset of patients who may benefit more from MA withdrawal and the initiation of alternative regimens. However, these data need further confirmation with a larger pool of patients.

Aged↗

PubMed1999

Characterization of neoplastic and normal human breast tissues with in vivo (1)H MR spectroscopy.

The purpose of this study was to evaluate whether the detection of choline-containing compounds in in vivo (1)H magnetic resonance spectroscopy (MRS) of breast lesions is specific for carcinomas, whether a choline peak in in vivo (1)H MRS can be detected under physiological conditions of increased metabolism in breast parenchyma, and whether analysis of lipid signals can differentiate between various breast lesions and tissues. Forty patients and volunteers were examined with in vivo (1)H MR spectroscopy. Three spectra with identical localization but increasing echo times were obtained. Choline-containing compounds were detected in 9 of 11 carcinomas and in 2 of 11 benign lesions. A choline signal was also detected in five of seven volunteers who were breast-feeding at the time of examination, demonstrating that choline compounds can be detected by in vivo (1)H MRS in breast tissue under physiological conditions. Analysis of lipid signals did not contribute to differentiation between various breast lesions and tissues. J. Magn. Reson. Imaging 1999;10:159-164.

Adult↗

PubMed1999

Effects of treatment with megestrol acetate on the insulin-like growth factor system: time and dose dependency.

This study was designed to evaluate time and dose dependency of alterations in insulin-like growth factor (IGF)-I, free IGF-I and the functional status of IGF-binding protein (IGFBP)-3 in breast cancer patients during treatment with megestrol acetate (MA). In 16 patients receiving MA 160 mg daily, total IGF-I levels increased gradually (significant after 3 days on treatment) by a maximum of 2.66-fold after 5-6 months on treatment. However, free (readily dissociable) IGF-I levels increased to a smaller extent (1.23-2.15-fold). This discrepancy may be due to an increase in intact IGFBP-3 determined by Western ligand blotting (WLB). Similar findings were observed in 12 patients treated with MA in escalating doses from 40-800 mg daily. A dose-dependent increase in IGF-I was observed up to a dose level of 120 mg daily. We conclude that treatment with MA caused a profound increase in plasma levels of total IGF-I accompanied by a moderate increase in free IGF-I. This may explain the anabolic effects of MA in patients suffering from cachexia, but refute the hypothesis that alterations in the IGF-system may contribute to the antitumour effects of MA in breast cancer patients.

Aged↗

PubMed1999

Dietary caffeine as a probe agent for assessment of cytochrome P4501A2 activity in random urine samples.

AIMS: To validate the use of randomly collected urine samples for assessment of cytochrome P4501A2 (CYP1A2) activity based on dietary caffeine (caffeine metabolic ratio, MRcaff ), and to relate the MRcaff to caffeine intake and smoking habits in a larger group of individuals. METHODS: Nineteen healthy volunteers were included in the validation study. Caffeine (100 mg) was ingested and a urine sample was collected after 6 h. Within the following week a random urine sample was collected in the individuals without a preceding test dose of caffeine. Urine samples were analysed for caffeine and its metabolites by h.p.l.c. and the (AFMU+1U+1X)/1,7U metabolic ratio was used to reflect CYP1A2 activity. In an extended investigation of 522 healthy pregnant women the MRcaff was related to intake of caffeine from various sources, and to smoking. RESULTS: The results from the random and standardised sampling methods correlate with each other (correlation coefficient of MRcaff was 0. 91). The MRcaff as assessed by the random sampling method in a larger population was not affected by source or amount of caffeine ingested. Significantly higher MRcaff was found in smokers compared to non-smokers. In the large group of individuals the random sampling method was possible to use in 80% of the cases. In the residual 20% one or several of the metabolite concentrations were too low or unmeasurable. CONCLUSIONS: Our study demonstrates that the random urine caffeine phenotyping method is possible to use in as many as 80% of the individuals when based on dietary caffeine. Our approach should prove applicable in most countries with widely spread caffeine consumption. The method is useful in larger studies of drug metabolising enzyme activities and minimises the time consumption and costs.

Caffeine↗

PubMed1999

Differentiating benign and malignant breast lesions with T2*-weighted first pass perfusion imaging.

PURPOSE: Invasive breast carcinomas and fibroadenomas are often difficult to differentiate in dynamic contrast-enhanced T1-weighted MR imaging of the breast, because both tumors can enhance strongly after contrast injection. The purpose of this study was to evaluate whether the addition of T2*-weighted first pass perfusion imaging can increase the differentiation of malignant from benign lesions. MATERIAL AND METHODS: Nine patients with invasive carcinomas and 10 patients with contrast enhancing fibroadenomas were examined by a dynamic contrast-enhanced T1-weighted 3D sequence immediately followed by a single slice T2*-weighted first pass perfusion sequence positioned in the contrast-enhancing lesion. RESULTS: The carcinomas and the fibroadenomas were impossible to differentiate based on the contrast enhancement characteristics in the T1-weighted sequence. The signal loss in the T2*-weighted perfusion sequence was significantly stronger in the carcinomas than in the fibroadenomas (p = 0.0004). CONCLUSION: Addition of a T2*-weighted first pass perfusion sequence with a high temporal resolution can probably increase the differentiation of fibroadenomas from invasive carcinomas in contrast-enhanced MR imaging of the breast.

Adult↗