Residual kidney function after donor nephrectomy. Assessment by 99mTc-MAG3-clearance

AIM

We evaluated the long-term residual renal function after donor nephrectomy using 99mTc-mercaptoacetyltriglycin (MAG3)-clearance.

DONORS, METHODS

Altogether 49 kidney donors were examined using 99mTc-MAG3-clearance after nephrectomy for donation to a relative (m:f = 11:38; age 55+/-27 years). The donors were examined 16+/-8 years postoperatively (1.5-26 years). 42 donors (86%) showed normal creatinine values, whereas the other seven (14%) exhibited slightly elevated levels. 20 donors were examined pre- and postoperatively and compared intraindividually. The kidney function was compared to the age adapted normal values of healthy persons with two kidneys (67-133% of age related mean).

RESULTS

After nephrectomy all donors showed a normal perfusion, good secretion, merely physiological intrarenal transit and a normal elimination from the kidneys. The 99mTc-MAG3-clearance was 69+/-15% of the normal mean value of healthy carriers of two kidneys regardless of the gender. 20 donors with a preoperative examination showed a significantly reduced total renal function from 84+/-15% of the mean normal value preoperatively to 60+/-15% postoperatively (p <0.0005). 15 donors of this group exhibited a significant functional increase of the residual kidney from 40% initially to 60% after nephrectomy (p = 0.003). No correlation was found between the initial-99mTc-MAG3-clearance measured prior to nephrectomy and the clearance levels after nephrectomy. Also, no correlation between the preoperative 99mTc-MAG3-clearance and the postoperative serum creatinine values could be observed. Altogether, 22% of the donors (11/49) developed arterial hypertension 10+/-8 years after donation (1-23 years). This corresponds to the normal age prevalence of hypertension in the carriers of two kidneys. Three donors suffered from arterial hypertension prior to the operation.

CONCLUSION

Kidney donors with normal or slightly elevated creatinine values postoperatively show a 99mTc-MAG3-clearance value of 69% of the mean value of healthy carriers of two kidneys. This may serve as a reference value for healthy carriers of one kidney. In our study we demonstrated a good compensation of the contralateral kidney via renal scintigraphy by means of 99mTc-MAG3-clearance.

Limitations of dual time point FDG-PET imaging in the evaluation of focal abdominal lesions

AIM

For the evaluation of the diagnostic potential of dual time point FDG positron emission tomography (PET) in patients with suspicious focal abdominal uptake, dual time point PET imaging was compared with clinical findings.

PATIENTS, METHODS

In a prospective study, 56 patients exhibiting a solitary suspicious, intense abdominal FDG uptake, underwent dual time point PET imaging for staging or restaging of different malignant tumors, maximal standardized uptake value (SUVmax) measurements included. The first acquisition was started 64.8 +/- 19.5, the second 211.3 +/- 52.5 min after FDG injection. The final diagnosis based on CT or MRT imaging and a follow-up period of 12.6 +/- 2.8 months. Additionally, colonoscopy was done in 6 patients. In another 6 patients histopathology was obtained from CT guided biopsy.

RESULTS

Malignant focal abdominal lesions with a SUVmax <2.5 (n = 4) showed an uptake increase of > or =30%. In the remaining malignant cases with an uptake of > or =2.5 (n = 11), uptake increased in 64% and decreased in 36%. Malignant lesions showing FDG uptake decrease (n = 4) had an initial SUVmax value > or =2.5 and remained with a SUVmax > or =2.5 in the second imaging. In benign lesions with an initial SUVmax > or =2.5 (n = 31), the uptake increased in 17 patients (55%) and decreased in 14 patients (45%). All lesions which changed configuration (33%) were confirmed as benign (n = 5).

CONCLUSION

Using dual time point PET abdominal lesions show a very hetergenous uptake pattern regardless of their dignity. Malignancy can only be reliably excluded in lesions which change their configuration and in lesions with an initial SUVmax value <2.5 combined with an SUV decrease in the delayed imaging. Particularly abdominal lesions which show an initial SUVmax > or =2.5 combined with a SUV increase in the delayed imaging are suspicious for malignancy and need further clarification.

OLAV-PMF: a novel scoring scheme for high-throughput peptide mass fingerprinting

We propose a new type of probabilistic scoring scheme framework for protein identification from peptide masses. We first introduce the framework itself and explain its requirements. In a second part, we describe a particular implementation and test it on a data set of more than 8000 MALDI-TOF spectra with known contents. Doing so, we also compare its performance to two widely used scoring schemes, thereby demonstrating the potential of the proposed approach.

The effect of preoperative antiplatelet therapy in coronary artery surgery: blood transfusion requirements for patients on cardiopulmonary bypass

INTRODUCTION

Bleeding after heart operations remains a common complication and contributes to morbidity and death. Recent studies have suggested that antiplatelet therapy (APT) may not increase homologous blood requirements in coronary bypass surgery. The purpose of this study was to examine the influence of APT therapy on haemorrhage and transfusion requirements in patients undergoing coronary artery bypass (CABG) on cardiopulmonary bypass (CPB).

MATERIALS AND METHODS

Records from 290 consecutive patients who underwent CABG with CPB were retrospectively reviewed, including 145 patients who received APT within 5 days prior to surgery and 145 control patients (CON). Blood loss was measured up to 24 h. Demographic and clinical patient data were collected until hospital discharge.

RESULTS

Both groups were well matched with respect to demographic and intra-operative data. There was significantly (p < 0.0005) more mediastinal tube drainage at 24 h in the APT group (1123 mL +/- 537 mL) compared to CON patients (874 mL +/- 351 mL). In addition, the APT group received significantly more units of blood (APT: 2.6 +/- 2.5 vs CON: 1.6 +/- 1.8; p < 0.0005), platelet units (APT: 1.2 +/- 1.8 vs CON: 0.2 +/- 0.8; p < 0.0005), and fresh frozen plasma units (APT: 2.0 +/- 2.2 vs CON: 1.3 +/- 2.0; p = 0.01).

CONCLUSION

This study suggests consideration should be given to delaying elective CABG for patients who have received APT treatment until APT is discontinued for at least 5 days.

Case report: drug interference with MIBG uptake in a patient with metastatic paraganglioma

Metaiodobenzylguanidine (MIBG) labelled with iodine-131 ((131)I) has become a well established therapeutic tool for inoperable metastastic tumours of paraganglioma. There are different pharmacological substances known to interfere with MIBG-uptake which may result in a false negative MIBG scan. We present the case of a 26-year-old male polytoxicomanic patient with metastatic paraganglioma, who underwent MIBG therapy. During earlier therapies, MIBG uptake in the metastatic lesions was very high. A post-therapeutic whole-body scan subsequent to recent (131)I-MIBG therapy failed to detect the vast majority of metastatic lesions-except for two. (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) showed metastases with a similar distribution to the initial MIBG scan. The possible reasons for the discrepancy in the findings of the MIBG scans and the (18)F-FDG-PET scan are discussed with special emphasis on drug intake prior to MIBG administration, increased MIBG turn-over and unknown drug mixture interference with MIBG uptake.

Industrial-scale proteomics: From liters of plasma to chemically synthesized proteins

Human blood plasma is a useful source of proteins associated with both health and disease. Analysis of human blood plasma is a challenge due to the large number of peptides and proteins present and the very wide range of concentrations. In order to identify as many proteins as possible for subsequent comparative studies, we developed an industrial-scale (2.5 liter) approach involving sample pooling for the analysis of smaller proteins (M(r) generally < ca. 40 000 and some fragments of very large proteins). Plasma from healthy males was depleted of abundant proteins (albumin and IgG), then smaller proteins and polypeptides were separated into 12 960 fractions by chromatographic techniques. Analysis of proteins and polypeptides was performed by mass spectrometry prior to and after enzymatic digestion. Thousands of peptide identifications were made, permitting the identification of 502 different proteins and polypeptides from a single pool, 405 of which are listed here. The numbers refer to chromatographically separable polypeptide entities present prior to digestion. Combining results from studies with other plasma pools we have identified over 700 different proteins and polypeptides in plasma. Relatively low abundance proteins such as leptin and ghrelin and peptides such as bradykinin, all invisible to two-dimensional gel technology, were clearly identified. Proteins of interest were synthesized by chemical methods for bioassays. We believe that this is the first time that the small proteins in human blood plasma have been separated and analyzed so extensively.

200 Sentinel lymph node biopsies without axillary lymph node dissection -- no axillary recurrences after a 3-year follow-up

The aim of this study is to evaluate the rate of axillary recurrences in sentinel lymph node (SLN)-negative breast cancer patients after sentinel lymph node biopsy (SLNB) alone without further axillary lymph node dissection (ALND). Between May 1999 and February 2002, 333 consecutive patients with primary invasive breast cancer up to 4 cm and clinically negative axillae were entered into this prospective study. Sentinel lymph nodes were identified using the combined method with blue dye (Patent blue V®) and technetium 99m-labelled albumin (Nanocoll®). Sentinel lymph nodes were examined by frozen sections, standard haematoxylin and eosin staining and immunohistochemistry staining. In SLN-positive patients, ALND was performed. Sentinel lymph node-negative patients had no further ALND. The SLN identification rate was 98.5% (328 out of 333). In all, 128 out of 328 (39.0%) patients had positive SLNs and complete ALND. A total of 200 out of 328 (61.0%) patients were SLN negative and had no further ALND. The mean tumour size of SLN-negative patients was 16.5 mm. The mean number of SLNs removed was 2.1 per patient. There were no local or axillary recurrences at a median follow-up of 36 months. The absence of axillary recurrences after SLNB without ALND in SLN-negative breast cancer patients supports the hypothesis that SLNB is accurate and safe while providing less surgical morbidity than ALND. Short-term results are very promising that SLNB without ALND in SLN-negative patients is an excellent procedure for axillary staging in a cohort of breast cancer patients with small tumours.

The influence of thyroglobulin on functional imaging in differentiated thyroid cancer

AIM

Recombinant human thyroid stimulating hormone (rhTSH) for an exogenous stimulation of TSH and consequent thyroglobulin (hTG) synthesis has reinitiated a discussion about the usefulness of diagnostic procedures for the follow-up of differentiated thyroid cancer (DTC).

METHOD

Fifty consecutive patients with DTC who received whole-body iodine scintigraphy (WBS) and positron emission tomography (PET) were evaluated.

RESULTS

The work-up was normal in 18/50. In 32 patients, functional imaging detected DTC. In 44% exogenous TSH stimulation with rhTSH was used and thyroxin was withdrawn in the others. The hTG under stimulation ranged from 0.8 to 5.004 ng x ml(-1). It was below 2 ng x ml(-1) in four (12.5%) patients. In total, 91 tumour sites were identified by positron emission tomography (PET) and 47 sites by WBS. PET and WBS showed corresponding uptake in 38% of lymph node, 48% of parenchymal and 43% of bone metastases. PET detected additional 53% of lymph node (WBS 9%), 38% of parenchymal (WBS 14%) and 28.5% of bone metastases.

CONCLUSION

It is concluded that PET is more sensitive than WBS for the detection of DTC. The follow-up of DTC patients with hTG levels alone misses a significant number of true positive cases. Its use should therefore be restricted to selected low risk patients only.

Prefabrication of vascularized bone grafts using recombinant human osteogenic protein-1—part 3: dosage of rhOP-1, the use of external and internal scaffolds

In a previous study vascularized bone grafts were prefabricated with recombinant human osteogenic protein-1 (rhOP-1) using blocks of xenogenic bone mineral (BioOss) as scaffolds. The present study addressed the dosage of rhOP-1 and the combination of an external (mould) and internal scaffold (granular BioOss). In five Göttingen minipigs six prefabrication sites in the latissimus dorsi muscles were randomly assigned to groups a-f. Moulds were prepared by shaping collagen/polylactide membranes in a cylindrical form which was filled with 1g BioOss granules and rhOP-1 (a: 0; b: 50; c, f, e: 250; d: 1000 microg of rhOP-1, a-e: cylinder open to muscle, e cylinder perforated, f: cylinder open to subcutaneous fat). After 6 weeks a dose dependency of bone density (a-d: 0%; 9.4%; 15.8%; 31.1%) and vessel density (a-d: 0.3; 2.4; 7.9; 25.4 counts/view) was observed histomorphometrically. Muscular surrounding was advantageous to subcutaneous tissue. Perforations of the membranes increased vessel density and did not impair bone formation. Bone density decreased in the proximity of the polylactide membranes. The membrane material was too soft and partly collapsed and therefore needs not to be reconsidered. The use of BioOss granules with 1000 microg rhOP-1 per gram proved to be a suitable concept for prefabrication of bone transplants.

Atypical thoracic and supraclavicular FDG-uptake in patients with Hodgkin's and non-Hodgkin's lymphoma

AIM

In FDG-PET imaging abnormal supraclavicular and paravertebral FDG uptake is a frequent finding which recently could be demonstrated to partly represent brown fat tissue. This study was carried out to further investigate causes for this phenomenon. Patients variables such as age, gender, body mass index (BMI) and the value of sedation and delayed imaging were compared with the presence of atypical uptake in 2 distinct groups of diseases, Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL).

METHODS

PET images of 81 patients (53 HD and 28 NHL) were evaluated for atypical uptake. In 5 patients additional delayed images were acquired. Sedatives were used in anxious patients (n=45).

RESULTS

Twelve out of 53 patients with HD and 2 out of 28 patients with NHL showed an atypical uptake. The BMI of patients with atypical uptake (median, 21 kg/m2 versus 24 kg/m2; p<0.05) and the age (median, 25 y versus 44 y; p<0.05) were significantly lower compared with patients without atypical uptake. In nearly 50% of all women with HD= or <30 y and 20% of all male patients with HD= or <30 y an atypical uptake was observed. Delayed images showed a SUVmax decrease in 4 patients and an increase in 1 patient. All patients with atypical uptake received sedatives which had an anxiolytic effect in all patients, but did not prevent atypical uptake.

CONCLUSION

Abnormal supraclavicular and paravertebral FDG accumulation occurs particularly in younger patients and those with lower BMI values. The use of sedatives or delayed acquisition does not increase the diagnostic information in these cases.

Monitoring the efficacy of iodine-131-MIBG therapy using fluorine-18-FDG-PET

BACKGROUND

The purpose of this study was to assess the potential of fluorine-18 fluoro-2-deoxy-d-glucose positron emission tomography (18F-FDG-PET) for monitoring the efficacy of iodine-131 metaiodobenzylguanidine (131I-MIBG) therapy in neuroendocrine tumours.

METHODS

A total of seven 131I-MIBG therapies with 3.7 to 10.2 GBq were carried out in three patients suffering respectively from a phaeochromocytoma, a paraganglioma and a metastatic neuroendocrine tumour of an unknown primary. The post-therapeutic whole-body scintigrams were compared with the results of six 18F-FDG-PET studies performed at the time of the therapies. One patient received three PET scans prior to each one of the MIBG therapies, and one patient was studied twice.

RESULTS

18F-FDG uptake in tumour sites seemed to correlate well with tumour differentiation, showing no uptake in one patient with a highly differentiated neuroendocrine tumour, and moderate-to-intense uptake in the two other patients with metastatic disease. Those tumour sites that had a simultaneous positive uptake in both the MIBG scintigram and the PET scan showed response to therapy as a continuous reduction in MIBG uptake over time. They also showed a qualitative decrease in FDG accumulation during the follow-up. This was associated with a decrease in the mean and maximum standard uptake values of more than 50 % in some metastases, while the X-ray computed tomography showed no decrease in tumour volume. Two patients revealed additional metastases that were unknown on the basis of prior diagnostic or therapeutic PET scans and radiological follow-up.

CONCLUSIONS

It may be concluded from these cases that 18F-FDG-PET is a valuable tool for an initial metabolic staging of neuroendocrine tumours prior to 131I-MIBG therapy, as it can reveal tumour sites beyond the reach of radioisotope therapy. It may also be of importance in assessing therapeutic potential in those tumour sites that do show positive MIBG uptake.

Trypsin catalyzed 16O-to-18O exchange for comparative proteomics: tandem mass spectrometry comparison using MALDI-TOF, ESI-QTOF, and ESI-ion trap mass spectrometers

Quantitative or comparative proteome analysis was initially performed with 2-dimensional gel electrophoresis with the inherent disadvantages of being biased towards certain proteins and being labor intensive. Alternative mass spectrometry-based approaches in conjunction with gel-free protein/peptide separation have been developed in recent years using various stable isotope labeling techniques. Common to all these techniques is the incorporation, biosynthetically or chemically, of a labeling moiety having either a natural isotope distribution of hydrogen, carbon, oxygen, or nitrogen (light form) or being enriched with heavy isotopes like deuterium, (13)C, (18)O, or (15)N, respectively. By mixing equal amounts of a control sample possessing for instance the light form of the label with a heavy-labeled case sample, differentially labeled peptides are detected by mass spectrometric methods and their intensities serve as a means for direct relative protein quantification. While each of the different labeling methods has its advantages and disadvantages, the endoprotease (16)O-to-(18)O catalyzed oxygen exchange at the C-terminal carboxylic acid is extremely promising because of the specificity assured by the enzymatic reaction and the labeling of essentially every protease-derived peptide. We show here that this methodology is applicable to complex biological samples such as a subfraction of human plasma. Furthermore, despite the relatively small mass difference of 4 Da between the two labeled forms, corresponding to the exchange of two oxygen atoms by two (18)O isotopes, it is possible to quantify differentially labeled proteins on an ion trap mass spectrometer with a mass resolution of about 2000 in automated data dependent LC-MS/MS acquisition mode. Post column sample deposition on a MALDI target parallel to on-line ESI-MS/MS enables the analysis of the same compounds by means of ESI- and MALDI-MS/MS. This has the potential to increase the confidence in the quantification results as well as to increase the sequence coverage of potentially interesting proteins by complementary peptide ionization techniques. Additionally the paired y-ion signals in tandem mass spectra of (16)O/(18)O-labeled peptide pairs provide a means to confirm automatic protein identification results or even to assist de novo sequencing of yet unknown proteins.

Paraneoplastic syndromes: detection of malignant tumors using [(18)F]FDG-PET

AIM

Paraneoplastic syndromes (PS) comprise a variety of clinical symptoms and diseases associated with underlying malignancy. Differentiation towards benign autoimmune diseases is necessary due to different therapeutic options. This diagnostic challenge includes cost- and time-consuming methods and is not successful in many cases. The aim of this study was the evaluation of [(18)F]fluorodeoxyglucose positron emission tomography ([(18)F]FDG-PET) for detecting or ruling out malignancy in these patients.

METHODS

In this retrospective work-up a total of 30 patients with suspected PS (m:f = 17:13, mean age 55, range 22-76 years) were examined with [(18)F]FDG-PET between 1996 and 2001. Diagnoses were erythrodermia, cerebellar degeneration, dermatomyositis, polyneuropathia and others. PET scans were compared to histopathological (n=14), radiological and follow up data (mean follow up 3.6 years, range 1-6 years).

RESULTS

In 7 out of 30 patients (23%) an underlying malignancy was detected. Six out of 7 malignant neoplasms showed a distinctly increased glucose consumption. One benign neoplasm caused increased tracer uptake, another PET positive patient refused biopsy and showed no growth of a malignant tumour during clinical follow up of 28 months. The remaining 21 patients without suspicious glucose consumption did not demonstrate a malignancy in other diagnostic modalities or during subsequent clinical follow-up.

CONCLUSION

[(18)F]FDG-PET seems to be a useful tool in the diagnostic work-up of patients with suspected paraneoplastic syndrome.

[Sentinel lymph node biopsy in breast cancer patients--results and experience after 500 sentinel lymph node biopsies]

INTRODUCTION

Sentinel lymph node biopsy (SLNB) is a widely used technique for axillary staging in breast cancer patients. The principle to evaluate the axillary status of a breast cancer patient with a less invasive surgery than axillary lymph node dissection (ALND) meets the new minimally invasive concept in breast cancer surgery. Some breast cancer centers proceed to SLNB without ALND in SLN-negative patients.

PATIENTS AND METHODS

Between March 1998 and March 2002, 500 SLNBs were performed. After a learning period with SLNB and ALND in 75 patients with a sensitivity of 96.2% and a false-negative rate of 3.8%, SLNB alone without further ALND was performed in a group of patients. In addition, the feasibility of SLNBin patients with locally advanced breast cancer, in patients after neoadjuvant chemotherapy and in patients with multicentricity was evaluated. The combined method with blue dye and technetium-99m-labeled human albumin for identification of SLNs was applied.

RESULTS

500 SLNBs were performed. The identification rate was 86.2%. After exclusion of patients with neoadjuvant chemotherapy and patients with multicentricity, the identification rate was 94.5%. SLNs were positive in 41.3% of patients and negative in 58.7% of patients.

DISCUSSION

SLNB is an excellent method for axillary stag-ing and an alternative for ALND in a certain group of breast cancer patients.

Sentinel lymph node biopsy alone without axillary lymph node dissection--follow up of sentinel lymph node negative breast cancer patients

AIMS

To evaluate the rate of axillary recurrences in sentinel lymph node (SLN) negative breast cancer patients after sentinel lymph node biopsy (SLNB) alone without further axillary lymph node dissection (ALND).

METHODS

Between May 1999 and February 2001 all patients who had primary invasive breast cancer and were SLN negative were eligible for this prospective study. SLNB was performed by using the combined method with radioactive tracer and blue dye. SLNs were examined by frozen section, standard H/E staining and immunohistochemistry staining. SLN negative patients did not receive further ALND. Follow-up was done three-monthly with clinical controls, blood samples and ultrasound of the breast and axilla. An annual mammogram was performed.

RESULTS

116 patients with T1 or T2 invasive breast cancer were included in this trial. All 116 patients had negative SLNs in frozen sections, in H/E staining and in immunohistochemistry staining. The mean number of removed SLNs was 2.03+/-1.22. Mean tumor size was 17.15+/-7.62 mm. Postmenopausal patients totalled 79.3 and 20.7% of patients were premenopausal. No local or axillary recurrences occurred at a mean duration of follow-up of 22.12+/-6.38 months.

CONCLUSION

The absence of axillary recurrences after SLNB without ALND in SLN negative breast cancer patients supports the hypothesis that SLNB is accurate and safe while providing less surgical morbidity. Short term results are very promising. SLNB without ALND in SLN negative patients is an excellent procedure for axillary staging in a cohort of breast cancer patients with small tumors.

[Positron-emission tomography in oncology]

This review analyses clinical results, new trends and recommendations of the leading medical centers concerning application of positron-emission tomography (PET) with F-18 fluorodeoxyglucose (F18 FDG) in cancer patients. This method of radionuclide visualization has been widely introduced for the last decade in diagnosis of cancer of unknown primary location, or CUP-syndrome, bronchogenic cancer of the lungs, cancer of the head and neck, malignant lymphoma and melanoma, colorectal and neuroendocrine cancer. Efficacy of this procedure, physiological grounds, performance are considered. Potentialities of F18 FDG PET are demonstrated in tumor screening, detection of metastases, recurrences after surgical, radiation or drug antitumor treatment or monitoring. In combination with CT, MRT, USI and other techniques, F18 FDG PET raises accuracy of the diagnosis of pathological changes at any stage of cancer with resulting improvement in further therapeutic and follow-up efficacy.

Subclinical hyperthyroidism in dementia and correlation of the metabolic index in FDG-PET

AIM

Thyroid hormone status and thyroid antibodies were evaluated in patients suffering from dementia for further study of an association of hyperthyroidism with AD and vascular dementia (VD), respectively.

PATIENTS

In 77 patients with dementia, and 42 controls, thyrotropin (TSH) and thyroid antibodies were correlated with the different types of dementia and the metabolic index (MI) based on imaging with F-18-2-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET).

RESULTS

Twenty-two of all patients with dementia (29%) had borderline (TSH 0.3-0.5 mU/l) or decreased TSH levels (TSH < 0.3 mU/L). TSH values were significantly lower in patients suffering from AD (median: 1.1 mU/l) and VD (0.5 mU/l) than in the control group (1.5 mU/l) (p < 0.01). Decreased or borderline TSH levels were present in 52% of the patients with VD, but in only 10% of the controls, and in 23% of the patients with AD. Antibodies to thyroid peroxidase were positive in 16% of all patients with dementia. The MI in patients suffering from AD with borderline TSH levels was 0.81 (0.70, 0.94). In contrast, patients suffering from AD with normal TSH values showed a slightly higher MI of 0.84 (0.76, 0.89) (p = n.s.).

CONCLUSION

Decreased or borderline TSH values are associated with an increased probability of having dementia, especially VD.

[Positron emission tomography for the preoperative staging of esophageal carcinoma]

BACKGROUND AND OBJECTIVE

Exact preoperative staging is a prerequisite for the indication as well as the choice of the appropriate operative technique for patients with esophageal carcinoma. In this prospective study we assessed whether positron emission tomography (PET) with (18)F-fluorodeoxyglucose (FDG) increases the accuracy of staging compared to standard computer tomography (CT) and leads to a different therapeutic approach.

PATIENTS AND METHODS

30 patients (25 men, 5 women, median age 63 years) with histologically identified carcinoma of the esophagus (n =29) and the cardia (n = 1), respectively, were studied. All patients underwent FDG-PET imaging of the neck, chest, and abdomen as well as CT of the chest and abdomen. Sensitivity, specificity and accuracy were calculated for FDG-PET and CT to evaluate the detection of histologically identified lymph node metastases and distant metastatic disease.

RESULTS

FDG-PET showed higher specificity whereas the accuracy of the CT proved to be higher not only for the detection of abdominal lymph node metastases (67 % vs. 46 %), but also for lymph node metastases of the thorax (71 % vs. 50 %). Furthermore, the accuracy of the CT for the detection of blood-bone and lymphatic distant metastases was also higher than that of FDG-PET (72 % vs. 68 %). FDG-PET was more specific (100 % vs. 71 %) albeit less sensitive than CT-imaging (27 % vs. 73 %).

CONCLUSION

In our study, FDG-PET did not increase the accuracy of standard staging (CT) in patients with carcinoma of the esophagus. Therefore, no new consequences resulted for the operative indication as well as therapeutic procedure. Due to the high costs involved with PET investigation, this form of staging is momentarily indicated mainly for use in clinical studies, and in cases where CT does not offer unequivocal results. Increase in sensitivity of the already advantageous whole-body FDG-PET imaging by means of tumor-affinitive radiopharmaceuticals as well as optimized apparatus resolution could lead to new indications for this staging procedure.

Discrimination between Alzheimer dementia and controls by automated analysis of multicenter FDG PET

A new diagnostic indicator of FDG PET scan abnormality, based on age-adjusted t statistics and an automated voxel-based procedure, is presented and validated in a large data set comprising 110 normal controls and 395 patients with probable Alzheimer's disease (AD) that were studied in eight participating centers. The effect of differences in spatial resolution of PET scanners was minimized effectively by filtering and masking. In controls FDG uptake declined significantly with age in anterior cingulate and frontolateral perisylvian cortex. In patients with probable AD decline of FDG uptake in posterior cingulate, temporoparietal, and prefrontal association cortex was related to dementia severity. These effects were clearly distinct from age effects in controls, suggesting that the disease process of AD is not related to normal aging. Women with probable AD had significantly more frontal metabolic impairment than men. The new indicator of metabolic abnormality in AD-related regions provided 93% sensitivity and specificity for distinction of mild to moderate probable AD from normals, and 84% sensitivity at 93% specificity for detection of very mild probable AD (defined by Mini Mental Score 24 or better). All regions related to AD severity were already affected in very mild AD, suggesting that all vulnerable areas are affected to a similar degree already at disease onset. Ventromedial frontal cortex was also abnormal. In conclusion, automated analysis of multicenter FDG PET is feasible, provides insights into AD pathophysiology, and can be used potentially as a sensitive biomarker for early AD diagnosis.

The role of the laser pulse duration in infrared matrix-assisted laser desorption/ionization mass spectrometry

The role of the laser pulse duration in matrix-assisted laser desorption/ionization mass spectrometry with infrared lasers (IR-MALDI-MS) emitting in the 3 microm wavelength range has been evaluated. Mass spectrometric performance and characteristics of the IR-MALDI process were examined by comparing a wavelength-tuneable mid-infrared optical parametric oscillator (OPO) laser of 6 ns pulse duration, tuned to wavelengths of 2.79 and 2.94 microm, with an Er:YAG laser (lambda = 2.94 microm) with two pulse durations of 100 and 185 ns, and an Er:YSGG laser (lambda = 2.79 microm) with a pulse duration of 75 ns. Threshold fluences for the desorption of cytochrome C ions were determined as a function of the laser pulse duration for various common IR-MALDI matrices. For the majority of these matrices a reduction in threshold fluence by a factor of 1.2-1.9 was found by going from the 75-100 ns long pulses of the Erbium lasers to the short 6 ns OPO pulse. Within the experimental accuracy threshold fluences were equal for the 100 and the 185 ns pulse duration of the Er:YAG laser. Some pronounced pulse duration effects related to the ion formation from a glycerol matrix were also observed. The effect of the laser pulse length on the duration of ion emission was furthermore investigated.

Intraoperative radiotherapy given as a boost after breast-conserving surgery in breast cancer patients

Conventional radiotherapy after breast-conserving therapy is confined to 50-55 Gy external beam radiation therapy (EBRT) to the whole breast and 10-16 Gy external boost radiation to the tumour bed or brachytherapy to the tumour bed. Local recurrence rate after breast-conserving surgery varies between 5 and 18%. External boost radiation can partially miss the tumour bed and therefore can result in local failure. Intra-operative radiotherapy (IORT) as a high precision boost can prevent a 'geographical miss'. From October 1998 to December 2000, 156 patients with stage I and stage II breast cancer were operated upon in a dedicated IORT facility. After local excision of the tumour, the tumour bed was temporarily approximated by sutures to bring the tissue in the radiation planning target volume. A single dose of 9 Gy was applied to the 90% reference isodose with energies ranging from 4 to 15 MeV, using round applicator tubes 4-8 cm in diameter. After wound healing, the patients received additional 51-56 Gy EBRT to the whole breast. No acute complications associated with IORT were observed. In 5 patients, a secondary mastectomy had to be performed because of tumour multicentricity in the final pathological report or excessive intraductal component. 2 patients developed rib necroses. In 7 patients, wound healing problems occurred. After a mean follow-up of 18 months, no local recurrences were observed. Cosmesis of the breast was very good and comparable to patients without IORT. Preliminary data suggest that IORT given as a boost after breast-conserving surgery could be a reliable alternative to conventional postoperative fractionated boost radiation by accurate dose delivery and avoiding geographical misses, by enabling smaller treatment volumes and complete skin-sparing and by reducing postoperative radiation time by 7-14 days.

A cryptic deletion of 2q35 including part of the PAX3 gene detected by breakpoint mapping in a child with autism and a de novo 2;8 translocation

We report a de novo, apparently balanced (2;8)(q35;q21.2) translocation in a boy with developmental delay and autism. Cross species (colour) paint (Rx) and SKY FISH, forward and reverse chromosome painting, and FISH with subtelomeric probes were used to examine the patient's karyotype, but further rearrangements were not detected. FISH with region specific clones mapping near 2q35 and 8q21.2 breakpoints and STS mapping performed on the isolated derivative chromosomes were used to refine the location of the breakpoints further. A cryptic deletion of between 4.23 and 4.41 Mb in extent and involving at least 13 complete genes or transcription units was found at the breakpoint on 2q35. The deletion includes the promoter and 5' untranslated region of the paired box 3 (PAX3) gene. The child has very mild dystopia canthorum which may be associated with the PAX3 haploinsufficiency. The 8q21.2 breakpoint is within MMP16 which encodes matrix metalloproteinase 16. We postulate that the cryptic deletion and rearrangement are responsible for the patient's phenotype and that a gene (or genes) responsible for autism lies at 2q35 or 8q21.2. The results present a step towards identifying genes predisposing to autism.

Measurements of mean initial velocities of analyte and matrix ions in infrared matrix-assisted laser desorption ionization mass spectrometry

The mean initial velocities of analyte ions ranging in molecular weight from 1000 Da to 150 kDa and desorbed with a pulsed Er:YAG laser from various solid-state and liquid IR MALDI matrices were measured along with those of the matrix ions. Experiments with UV MALDI were performed for comparison in addition for a 2,5-dihydroxybenzoic acid preparation. Two different measurement principles were employed, (1) a delayed extraction method, relying on the initial velocity-dependent increase of flight times with delay time between laser and HV ion extraction pulse, and (2) a field-free drift method in which the first region of a two-stage ion source was varied in length and the flight times compared. The two methods yielded somewhat different values for the mean initial ion velocities. Based on a detailed discussion of the measurement principles it is suggested that the actual initial velocities of IR MALDI ions lie between the limits set by the two methods. The influences of the analyte-to-matrix ratio, laser fluence, and laser wavelength on the initial ion velocities were also investigated. Significant differences between the desorption mechanisms for liquid and solid-state matrices were observed.

Time-efficient T2 relaxometry of the entire hippocampus is feasible in temporal lobe epilepsy

OBJECTIVE

To test the clinical usefulness and reliability of a new dual-echo turbo-spin-echo (TSE) sequence for rapid and regional hippocampal T2 relaxometry.

METHODS

Hippocampal T2 relaxation time (HRT) was determined by a TSE sequence on three to four consecutive coronal images in 16 control subjects and 12 patients with mesial temporal lobe epilepsy. HRT was related to neuropathology findings in hippocampal specimens including neuronal cell density (ND), results of visual analysis of MR images, clinical outcome after epilepsy surgery, and hippocampal volumetry.

RESULTS

Rapid HRT differentiated patients from control subjects; all cases of hippocampal sclerosis (HS; n = 10) were correctly diagnosed. HRT showed a strong correlation with ND in CA1 (p < 0.02) and CA3 (p < 0.05). Diagnoses based on rapid relaxometry concurred fully with results of visual inspection. Mean HRT was prolonged ipsilaterally in all patients with excellent postoperative seizure outcome and bilaterally prolonged or normal in patients with poorer outcome. Rapid HRT was concordant with hippocampal volumetry in 10 of 12 patients. Regional HRT of control subjects revealed significantly higher values in the anterior than posterior hippocampus. In patients with unilateral HS, this gradient was absent. The gradient was also absent contralaterally to HS, although surgical outcome was excellent.

CONCLUSIONS

Hippocampal dual-echo TSE-relaxometry can be regarded a reliable technique to detect and quantify HS. With a scan time of 3.31 minutes and immediate off-line analysis lasting a few minutes only, TSE-T2 relaxometry is easy to integrate in the routine diagnostic assessment of hippocampal morphology in large numbers of patients.

Painful multifocal arthritis: therapy with rhenium 186 hydroxyethylidenediphosphonate ((186)Re HEDP) after failed treatment with medication--initial results of a prospective study

Eight patients (77 joints) with polyarthritis were treated systemically with 570 MBq (15.4 mCi) of rhenium 186 ((186)Re) hydroxyethylidenediphosphonate (HEDP). Pain and disease activity were assessed monthly. In six (75%) of eight patients, a single injection of (186)Re HEDP led to an improvement in disease activity. Systemic low-dose treatment with (186)Re HEDP can reduce pain and disease activity in patients with polyarthritis.

Radiation exposure and radiation protection of the physician in iodine-131 Lipiodol therapy of liver tumours

Intra-arterial iodine-131 labelled Lipiodol therapy for liver cancer has been investigated for safety and efficacy over a number of years, but data on radiation exposure of personnel have remained unavailable to date. The aim of this study was to assess the radiation exposure of the physician during intra-arterial 131I-Lipiodol therapy for liver malignancies and to develop appropriate radiation protection measures and equipment. During 20 intra-arterial administrations of 131I-Lipiodol (1110-1924 MBq), radiation dose equivalents (RDE) to the whole body, fingers and eyes of the physician were determined for (a) conventional manual administration through a shielded syringe, (b) administration with an automatic injector and (c) administration with a lead container developed in-house. Administration by syringe resulted in a finger RDE of 19.5 mSv, an eye RDE of 130-140 microSv, and a whole-body RDE of 108-119 microSv. The injector reduced the finger RDE to 5 mSv. With both technique (a) and technique (b), contamination of angiography materials was observed. The container allowed safe transport and administration of the radiopharmaceutical from 4 m distance and reduced the finger RDE to <3 microSv and the eye RDE to <1 microSv during injection. During femoral artery compression, radiation exposure to the fingers reached 170 microSv, but the whole-body dose could be reduced from a mean RDE of 114 microSv to 14 microSv. No more contamination occurred. In conclusion, radiation exposure was high when 131I-Lipiodol was administered by syringe or injector, but was significantly reduced with the lead container.

Molecular cloning of Xp11 breakpoints in two unrelated mentally retarded females with X;autosome translocations

Mental retardation is a very common and extremely heterogeneous disorder that affects about 3% of the human population. Its molecular basis is largely unknown, but many loci have been mapped to the X chromosome. We report on two mentally retarded females with X;autosome translocations and breakpoints in Xp11, viz., t(X;17)(p11;p13) and t(X;20)(p11;q13). (Fiber-) FISH analysis assigned the breakpoints to different subbands, Xp11.4 and Xp11.23, separated by approximately 8 Mb. High-resolution mapping of the X- chromosome breakpoints using Southern blot hybridization resulted in the isolation of breakpoint-spanning genomic subclones of 3 kb and 0. 5 kb. The Xp11.4 breakpoint is contained within a single copy sequence, whereas the Xp11.23 breakpoint sequence resembles an L1 repetitive element. Several expressed sequences map close to the breakpoints, but none was found to be inactivated. Therefore, mechanisms other than disruption of X-chromosome genes likely cause the phenotypes.

A translocation breakpoint cluster disrupts the newly defined 3' end of the SNURF-SNRPN transcription unit on chromosome 15

Balanced translocations affecting the paternal copy of 15q11--q13 are a rare cause of Prader-Willi syndrome (PWS) or PWS-like features. Here we report on the cytogenetic and molecular characterization of a de novo balanced reciprocal translocation t(X;15)(q28;q12) in a female patient with atypical PWS. The translocation breakpoints in this patient and two previously reported patients map 70-80 kb distal to the SNURF-SNRPN gene and define a breakpoint cluster region. The breakpoints disrupt one of several hitherto unknown 3' exons of this gene. Using RT--PCR we demonstrate that sequences distal to the breakpoint, including the recently identified C/D box small nucleolar RNA (snoRNA) gene cluster HBII-85 as well as IPW and PAR1, are not expressed in the patient. Our data suggest that lack of expression of these sequences contributes to the PWS phenotype.

Influence of the laser fluence in infrared matrix-assisted laser desorption/ionization with a 2.94 microm Er : YAG laser and a flat-top beam profile

The dependence of the signal intensity of analyte and matrix ions on laser fluence was investigated for infrared matrix-assisted laser desorption/ionization (IR-MALDI) mass spectrometry using a flat-top laser beam profile. The beam of an Er : YAG laser (wavelength, 2.94 microm; pulse width, 90 ns) was coupled into a sapphire fiber and the homogeneously illuminated end surface of the fiber imaged on to the sample by a telescope. Three different laser spot sizes of 175, 350 and 700 microm diameter were realized. Threshold fluences of common IR matrices were determined to range from about 1000 to a few thousand J m(-2), depending on the matrix and the size of the irradiated area. In the MALDI-typical fluence range, above the detection threshold ion signals increase strongly with fluence for all matrices, with a dependence similar to that for UV-MALDI. Despite the strongly different absorption coefficients of the tested matrices, varying by more than an order of magnitude at the excitation laser wavelength, threshold fluences for equal spot sizes were found to be comparable within a factor of two. With the additional dependence of fluence on spot size, the deposited energy per volume of matrix at threshold fluence ranged from about 1 kJ mol(-1) for succinic acid to about 100 kJ mol(-1) for glycerol.

Lymphoscintigraphy in breast cancer patients--comparison of peritumoural and intradermal injection

AIM of this study was to determine whether the sentinel lymph nodes (SLNs) can be accurately identified in breast cancer patients with intradermal injection of the radiotracer above the primary tumour in comparison to peritumoural injection.

METHODS

In 45 women with breast cancer we performed lymphoscintigraphy on two separate days. We injected Tc-99m nanocolloid on the first day peritumourally, and on a separate day intradermally. The results of both investigations using different injection sites were compared in order to determine the number and location of SLNs.

RESULTS

The SLN identification rate using peritumoural injection was 71% (32 of 45 patients) and 96% (43 out of 45 patients) using intradermal injection. In 62% (28 of 45 patients) the number and location of the SLNs were identical. In 97% (31 of 32 patients) in whom a SLN was detected using peritumoural injection, the same SLNs reappeared with intradermal injection. There were no false negative findings with the peritumoural administration of tracer whereas the intradermal administration approach resulted in a false negative rate of 13%.

CONCLUSION

In women with breast cancer the reproducibility of lymphoscintigraphy using peritumoural and intradermal injection sites was 62%. The intradermal injection modality enables the detection of a SLN in patients where the peritumoural injection failed but it has the disadvantage of a higher false negative rate in comparison to the peritumoural injection technique.