Detection of internal mammary chain infiltration in breast cancer patients by [18F]FDG PET/MRI. Therapy implications

OBJECTIVE

To evaluate the detection rate and therapeutic implication of the infiltration of the internal mammary chain (IMCI) by [18F]FDG PET/MRI for staging of patients with breast cancer.

METHODS

Prospective study including 41 women with breast cancer (stage ≥ IIB) staged by [18F]FDG PET/MR. Two-phase exam: breast imaging (prone), whole-body (supine). TNM stage assessed by peer consensus with Nuclear Medicine and Radiology specialists. Study of the afferent vessel (AV) to IMC by breast MRI. IMCI was correlated with age, AV-IMC, T stage, breast quadrants, axillary and distant infiltration. Therapeutic re-evaluation by a multidisciplinary committee.

RESULTS

IMCI detection rate of 34% (14/41), with 8/14 patients under 55 years of age. All 14 patients with IMCI showed AV-IMC, 6 of them (43.9%) without VA-axillary. Of 27/41 patients without IMCI, in 13 (48.1%) only AV-axillary was found, in the remaining 14 (51.9%), AV-axillary and AV-IMC was found. In 57% (8/14) tumours were multicentric and 42% (6/14) focal, in inner quadrants in 4/6 (66.7%). In 1/14 patient (7.1%) only IMCI was found, in 9/14 (64.3%) axillary and IMC, in 4/14 patients (28.6%) distant lesions were detected. Committee re-evaluation: no further treatment in 27/41 patients (65.8%), thoracic radiotherapy in 10/41 patients (24.4%), systemic therapy in 4/41 patients (9.7%).

CONCLUSION

Our detection rate of IMCI in breast cancer staging by [18F]FDG PET/MR was 34%. Related factors were age, multicentric tumours, inner quadrants, detection of AV-IMC, NM staging. The evidence of IMCI allowed tailored therapy, with thoracic radiotherapy implementation in 24.4% of patients.

Cross section for inelastic neutron scattering from 193Ir at 6 MeV

Two samples, one of natural iridium and the other of enriched ¹⁹³Ir, were irradiated with a monoenergetic neutron beam of energy 6.0 MeV at the Triangle Universities Nuclear Laboratory. The product of the ¹⁹³Ir [Formula: see text] Ir reaction was determined by means of measuring X-rays following electron conversion of the isomeric state at 80.2 keV in ¹⁹³Ir. The cross section for inelastic neutron scattering is reported disagreeing with the literature data.

Standardization of acquisition protocols using PET/CT with 18F-Choline in prostate cancer

AIM

To standardize acquisition protocols for ¹⁸F-Choline PET/CT to prevent from urine interference, to determine the best time point for the whole-body study, and to assess whether "dual point" acquisition allows for differentiating malignant vs. benign lesions.

METHODS

One hundred consecutive patients with prostate cancer were prospectively studied. Immediately after ¹⁸F-Choline injection, a pelvis study was acquired, and a whole-body was subsequently obtained 1 and 2 hours p.i. Mean SUVmax was obtained in regions and for every sequential imaging. Mean analysis (χ²) and SUV percentage change (2/1 hours; 1 hours/0 min) were obtained. Metabolic pattern dynamics were assessed: accumulative vs. clearance. Patient follow-up after therapy and directed classification whenever ethically possible were performed.

RESULTS

Fifty-three prostate foci, without disturbing urinary activity was ever found on early images. Accumulative pattern in 42, with percentage increase was: 0 min/1 hour: +16.7% (χ²0.94); 1/2 hours: +10,0% (χ² 0.83). Clearance pattern in 11, with percentage decrease: 0 min/1 hour: -21.4% (χ²0.91): -7.7% (χ²0.85), corresponding in 7 to initial staging and in 4 post-radiotherapy biochemical recurrence. Every infradiaphragmatic uptake (n: 24) showed accumulative pattern, with percentage increase of +9.1% (χ²0.97), all of them depicted on early imaging. As for 12 supradiaphragmantic uptake, 8 of them showed clearance pattern with percentage decrease: -13.0% (χ²0.95). Accumulative pattern showed in 4 of them with percentage increase +13.0% (χ² 0.96), thus being assessed as invasive/malignant. Every bone uptake (n: 18) showed accumulative pattern, with percentage increase: +17.1% (χ²0.95), all of them depicted on 1 hour imaging.

CONCLUSIONS

As for prostate assessment is concerned, dual point at 0 min/1 hour proved to be the best procedure. As for supradiaphragmatic lymph-nodes detection, dual point with 1/2 hours performed best. As for infradiaphragmatic and bone involvement, as well as for inconclusive findings, the 2 hour imaging increased our diagnostic confidence.

Assessment of the extension of pressure ulcers into soft tissue and osteomyelitis diagnosis using 18F-FDG PET/CT

The precise assessment of pressure ulcer extension in patients with neurological diseases has crucial therapeutic implications, especially in the early detection of fistula to interior structures and osteomyelitis. Two case reports are presented on patients with a similar ischial ulcer, in whom an ¹⁸F-FDG PET/CT study enabled a precise assessment of infectious complications in underlying tissues. These cases support the implementation of ¹⁸F-FDG PET/CT as a first-line technique in their management.

18F-FDG PET/CT in follow-up evaluation in pediatric patients with Langerhans histiocytosis

PURPOSE

We evaluated the impact of ¹⁸F-FDG PET/CT in identifying sites of active disease and to assess therapeutic follow up in a group of pediatric patients with Langerhans cell histiocytosis (LCH).

METHOD

During 2007-2013, 13 ¹⁸F-FDG PET/CT studies were performed for follow-up in 7 patients with a diagnosis of LCH (4 female, 3 male; 1-12 years-old). PET findings were analyzed and correlated with the CT and MRI. Findings were also follow-up by these techniques.

RESULTS

PET was negative in 4 patients (all diagnosed with bone lesions and one with pituitary involvement also). CT findings showed residual morphological bone lesions in all patients, and hypophysis MRI study showed no abnormal signal. PET remained negative at 10, 14, 25 and 28 months, and no new lesions on CT and MRI were detected. PET was positive in 3 patients (one with cervical lymphadenopathy and 2 with bone lesions, one also with pituitary involvement not identified by PET). CT findings showed pathological cervical lymphadenopathy (n=1), bone lesions (n=2) and also a pituitary MRI lesion (n=1). In a patient with cervical lymphadenopathy histology demonstrated LCH involvement. In the other 2 patients, PET remained positive with an increase of ¹⁸F-FDG bone uptake at 17 and 19 months.

CONCLUSION

In our preliminar study, ¹⁸F-FDG PET is a useful imaging procedure, along with other diagnostic tools, for identification of active lesions.

18F-FDG PET/CT in the Staging and Management of Breast Cancer: Value in Disease Outcome and Planning Therapy

In hormone receptor-positive locally advanced breast cancer, endocrine therapy becomes an integral part of the therapeutic strategy. There are now significant numbers of available hormonal directed compounds, including selective aromatase and mTOR inhibitors, which allow an important therapeutic advance in these patients. Sequential F-FDG PET/CT studies provided essential information regarding response to different treatments, including targeted therapies, and adverse therapeutic effects that helped to better define the right moment to implement each therapeutic approach.

The value of 11C-methionine PET in the early differentiation between tumour recurrence and radionecrosis in patients treated for a high-grade glioma and indeterminate MRI

OBJECTIVE

To evaluate the contribution of ¹¹C-Methionine PET in the early differentiation between tumour recurrence and radionecrosis in patients treated for a high grade glioma.

METHOD

The study included 30 patients with glioma (III/IV grade) treated with surgery/radiotherapy/chemotherapy (5-8 months) and with an indeterminate MRI. All patients underwent a ¹¹C-Methione PET (within 15 days of MRI) and studies were visually analysed (intensity and morphology of uptake), quantified (SUV max/SUV mean background), and coregistered to MRI (3D-Flair). Patient management was decided by the neuro-oncology committee to clinical and imaging follow-up, second-line treatment, or surgery.

RESULTS

There were 23 ¹¹C-Methionine PET studies visually positive. Morphology of uptake was focal in 15, diffuse in 4, and ring-shaped in 4. Three out of the focal uptake cases underwent resection (Histopathology +). Sixteen underwent second-line therapy (11 responded; 5 progressed). The 4 cases with ring-shaped uptake were followed-up, and progression was found in 2 (true-positive), and disease-free in 2 (follow-up of 6 and 7 months, respectively) (false-positive). Seven out of ¹¹C-Methionine studies PET were visually negative, and all of them were disease-free (follow-up of 3-12 months). SUV lesion/background was 2.79±1.35 in tumour recurrence, and 1.53±0.39 in radionecrosis (P<.05). Taking into account a SUV lesion/background threshold of 2.35, the sensitivity and specificity values were 90.5% and 100%, respectively.

CONCLUSION

Visual analysis, quantitative and PET/MRI coregistration of ¹¹C-Methionine PET showed their complementary role in patients with indeterminate MRI results, thus allowing early differentiation between tumour recurrence and radionecrosis, and helping in the individual therapy approach.

Peritoneal Cancer Index by (18)F-FDG PET/TC pre and post-hyperthermic intraperitoneal chemotherapy. Report of a case

Radical cytoreductive surgery followed by hyperthermic intraperitoneal chemotherapy increases survival in patients with end-stage peritoneal carcinomatosis, and who are under palliative therapy. The Peritoneal Cancer Index enables the tumor burden to be quantified during surgery, as well as treatment planning and patient prognosis. It is obtained by combining the tumor spread in 13 abdominal and pelvic regions with the largest tumor size. Fluorodeoxyglucose positron emission tomography/computed tomography is the technique of choice for those patients selected to undergo radical cytoreductive surgery followed by hyperthermic intraperitoneal chemotherapy, due to its higher detection rate of carcinomatosis, and since it allows extra-peritoneal disease staging. The simplified Peritoneal Cancer Index (9 regions defined by 2 transverse and 2 sagittal planes) obtained by fluorodeoxyglucose positron emission tomography/computed tomography allows correlation with the surgical procedure, therefore its standardization is advisable.

11C-Choline PET/CT in the primary diagnosis of prostate cancer: impact on treatment planning

AIM

Aim of the present study was to evaluate the usefulness of 11C-choline PET/CT for detecting lymphatic or haematogenous spread and for planning radiotherapy in patients with medium-to-high risk prostate cancer.

METHODS

We have included 61 consecutive patients recently diagnosed with cancer prostate by biopsy. All patients were classified as medium-to-high risk: Gleason: 7-9; PSA: 6.3-30.4 ng/mL; stage T2c (N.=20) or stage T3 (N.=41). Image acquisition began 5 min after intravenous injection of 11C-choline (656+119 MBq), starting at the pelvis and continuing craniocaudally. Images were interpreted visually to evaluate uptake by the prostate gland. Lymph nodes with 11C-choline uptake were considered invaded, regardless of their size. Bone lesions were considered positive when they showed greater focal uptake than the surrounding bone. In patients with evidence of lymph-node invasion or bone metastases (15 patients), disease was classified as locoregional, oligometastatic, or multimetastatic.

RESULTS

All patients had prostate gland uptake (20 focal, 8 bifocal, and 33 multifocal). Extraprostatic disease was present in 15 patients (24.6%), as follows: 9 (60%) in a single location: in an infradiaphragmatic lymph node (N.=6), in a supradiaphragmatic lymph node (N.=1), and in bone (M1) (N.=2). Six (40%) as multifocal invasion: with both infra- and supradiaphragmatic lymph node involvement (N.=2); with infradiaphragmatic lymph node involvement and M1 bone metastases (N.=3); and infra- and supradiaphragmatic lymph node involvement plus M1 bone metastases (N.=1). Disease was classified as locoregional (N.=6), oligometastatic (N.=5), and multimetastatic (N.=4). The 11 (73.3%) patients with locoregional and oligometastatic disease were selected to undergo intensity-modulated radiation therapy with dose escalation based on the PET findings.

CONCLUSION

Our results suggest that 11C-choline PET/CT is a useful one-stop diagnostic procedure for evaluating patients with medium/high risk prostate cancer scheduled for radical treatment. 11C-choline PET/CT can reliably rule out lymph node involvement and remote metastases, allowing to select candidates for radiotherapy and to plan their treatment.

[Diagnostic performance of bone scintigraphy and (11)C-Choline PET/CT in the detection of bone metastases in patients with biochemical recurrence of prostate cancer]

AIM

To compare bone scan (BS) with (11)C-Choline PET/CT for the detection of bone metastases in patients with biochemical recurrence of prostate cancer (PC).

MATERIAL AND METHODS

A total of 169 patients with biochemical recurrence of PC(PSA:2.4-58 ng/ml) who were referred for both exams (0-15 days-in-between) were included. Lesion-detection-rate per patients and lesions were analyzed for both BS and (11)C-Choline PET/CT. Metastasis diagnosis was reached by: biopsy, CT/(18)F-Fluoride PET/MRI confirmation, or evidence of progression in subsequent imaging procedures.

RESULTS

A total of 91 lesions were found to be active in BS and/or (11)C-choline PET/CT (40 patients), with 78 of which were metastatic. BS detected 38 blastic, 2 lytic and 10 non-CT-evident lesions. (11)C-Choline PET/CT detected 41 blastic, 4 lytic and 29 non-CT-evident lesions. BS and (11)C-Choline PET/CT sensitivities were 65.4% and 96.1%; specificities ere 38.5 and 92.3% (χ(2) 8.27, p<0.04). Both imaging techniques were negative in 118 patients. Tracer avid lesions were found in 51 patients: with 30/51 being BS and (11)C-Choline PET/CT concordant; in 21/51 patients had discordant lesions (kappa 0.712, p=0.00). Lesions were absolutely discordant in 10/19 patients,: 5 FN BS, 2 FP BS (degenerative changes; dysplasia), 1 FN (11)C-Choline PET/CT (blastic), 1 FP (11)C-Choline PET/CT (degenerative), 1 out of field-of-view lesion with (11)C-Choline PET/CT (tibia alone). (11)C-Choline PET/CT showed extraosseous involvement in 26/51 patients with bone metastases: 9 local recurrences, 5 infra-diaphragmatic-lymph-nodes, 2 supra-diaphragmatic, 5 local and infra-diaphragmatic, 4 infra- and supra-diaphragmatic, 1 supra-diaphragmatic and lung metastases.

CONCLUSION

(11)C-Choline PET/CT yielded better sensitivity and specificity than BS for the detection of bone involvement in patients with biochemical recurrence of PC and allowed extraosseous restaging, with an impact in the clinical management of these patients.

Chemical biology. A bump-and-hole approach to engineer controlled selectivity of BET bromodomain chemical probes

Small molecules are useful tools for probing the biological function and therapeutic potential of individual proteins, but achieving selectivity is challenging when the target protein shares structural domains with other proteins. The Bromo and Extra-Terminal (BET) proteins have attracted interest because of their roles in transcriptional regulation, epigenetics, and cancer. The BET bromodomains (protein interaction modules that bind acetyl-lysine) have been targeted by potent small-molecule inhibitors, but these inhibitors lack selectivity for individual family members. We developed an ethyl derivative of an existing small-molecule inhibitor, I-BET/JQ1, and showed that it binds leucine/alanine mutant bromodomains with nanomolar affinity and achieves up to 540-fold selectivity relative to wild-type bromodomains. Cell culture studies showed that blockade of the first bromodomain alone is sufficient to displace a specific BET protein, Brd4, from chromatin. Expansion of this approach could help identify the individual roles of single BET proteins in human physiology and disease.

Partner associations across sympatric broad-headed bug species and their environmentally acquired bacterial symbionts

Many organisms have intimate associations with beneficial microbes acquired from the environment. These host-symbiont associations can be specific and stable, but they are prone to lower partner specificity and more partner-switching than vertically transmitted mutualisms. To investigate partner specificity in an environmentally acquired insect symbiosis, we used 16S rRNA gene and multilocus sequencing to survey the bacterial population in the bacteria-harbouring organ (crypts) of 49 individuals across four sympatric broad-headed bug species (Alydus calcaratus, A. conspersus, A. tomentosus and Megalotomus quinquespinosus). Similar to other insect-bacteria associations, Burkholderia spp. were the most common residents of the crypts in all four insect species (77.2% of recovered sequences). Burkholderia presence was associated with prolonged survival to adulthood in A. tomentosus, suggesting a beneficial role of these specialized associations. Burkholderia were also found in environmental reservoirs in the insects' habitat, which may facilitate acquisition by insects by increasing Burkholderia-insect encounters. Symbiont establishment could also be facilitated by resistance to insect defences; zone of inhibition assays demonstrated that Burkholderia and other bacteria isolated from crypts are resistant to insect defences that limit growth of Escherichia coli. Alternatively, the insects' defences may not efficiently kill a broad range of bacteria. Although the symbiosis is targeted to Burkholderia, the insects' crypts housed other bacteria, including non-Burkholderiaceae species. There is no significant effect of host insect species on Burkholderia distribution, suggesting a lack of strong partner specificity at finer scales. The presence of frequent partner-switching between sympatric insects and their symbionts likely prevents tight co-evolutionary dynamics.

An analysis of geothermal and carbonic springs in the western United States sustained by deep fluid inputs

Hydrothermal springs harbor unique microbial communities that have provided insight into the early evolution of life, expanded known microbial diversity, and documented a deep Earth biosphere. Mesothermal (cool but above ambient temperature) continental springs, however, have largely been ignored although they may also harbor unique populations of micro-organisms influenced by deep subsurface fluid mixing with near surface fluids. We investigated the microbial communities of 28 mesothermal springs in diverse geologic provinces of the western United States that demonstrate differential mixing of deeply and shallowly circulated water. Culture-independent analysis of the communities yielded 1966 bacterial and 283 archaeal 16S rRNA gene sequences. The springs harbored diverse taxa and shared few operational taxonomic units (OTUs) across sites. The Proteobacteria phylum accounted for most of the dataset (81.2% of all 16S rRNA genes), with 31 other phyla/candidate divisions comprising the remainder. A small percentage (~6%) of bacterial 16S rRNA genes could not be classified at the phylum level, but were mostly distributed in those springs with greatest inputs of deeply sourced fluids. Archaeal diversity was limited to only four springs and was primarily composed of well-characterized Thaumarchaeota. Geochemistry across the dataset was varied, but statistical analyses suggested that greater input of deeply sourced fluids was correlated with community structure. Those with lesser input contained genera typical of surficial waters, while some of the springs with greater input may contain putatively chemolithotrophic communities. The results reported here expand our understanding of microbial diversity of continental geothermal systems and suggest that these communities are influenced by the geochemical and hydrologic characteristics arising from deeply sourced (mantle-derived) fluid mixing. The springs and communities we report here provide evidence for opportunities to understand new dimensions of continental geobiological processes where warm, highly reduced fluids are mixing with more oxidized surficial waters.

[Detection of tumors in the central zone of the prostate with 11C-Choline PET/CT]

Prostate tumors originate 68% in the peripheral region and 24% in the transitional region where tumors originating in the central zone are rare (8%). However, diagnosis of the tumors in the central zone is important since they exhibit greater aggressiveness conditioned by their location and different biological behavior. Magnetic resonance imaging shows problems in identifying lesions in the central prostate zone, since this region has a heterogeneous signal, mainly after the primary treatment. Ultrasound guided sextant biopsy shows a negative result in 28% of prostate tumors. Therefore, it is advisable to repeat or even to perform saturation biopsies. We present two patients, one of them with suspected biochemical prostate cancer and one with biochemical recurrence after radical treatment. In both, (11)C-Choline PET/CT allowed detection of the tumor focus in the central zone of the prostate, with negative complementary diagnostic test and biopsies.

[Incidence of focal myocardial (18)F-FDG uptake and correlation with coronary calcifications by PET/CT]

OBJECTIVE

To evaluate the incidence of (18)F-FDG focal uptake in the myocardium as well as its correlation with coronary vessel calcifications.

MATERIAL AND METHODS

A total of 130 patients who underwent an oncological PET/CT study were reviewed retrospectively. Sixty-five had undergone a myocardial perfusion study because of clinical suspicion of coronary artery disease (group 1). There were no significant differences in age and gender regarding another group of the same series (n=65; group 2). Focal myocardial (18)F-FDG uptake and the presence of coronary vessel calcifications were identified by 2 independent observers.

RESULTS

Group 1: in 18 out of 65 patients (28%) focal myocardial (18)F-FDG uptake was identified (5 had 2 foci; total: 23 foci). In 43 out of 65 studies (66%), calcification was identified in the coronary vessels. Group 2: in 6 out of 65 patients (9%) focal myocardial (18)F-FDG uptake was identified (1 had 2 foci; total: 7 foci). In 17 out of 65 studies (26%), calcification was identified in the coronary vessels. Comparative analysis: focal myocardial (18)F-FDG uptake and coronary vessel calcifications were more frequent in the group 1 patients (p<0.01). There was no correlation between the presence of coronary vessel calcifications and focal myocardial (18)F-FDG uptake in individual patients in both groups (group 1: p=0.7; group 2: p=0.163).

CONCLUSIONS

PET/CT allows simultaneous assessment of focal myocardial (18)F-FDG uptake and myocardial vessel calcifications. Patients with clinical suspicion of coronary artery disease have a higher incidence of focal myocardial (18)F-FDG uptake and coronary calcifications. However, (18)F-FDG focal uptake is often observed in sites remote from those with calcification.

Corneal disease in patients with chronic renal insufficiency undergoing hemodialysis

PURPOSE

To evaluate alterations of the corneal endothelium in patients undergoing hemodialysis for renal insufficiency.

METHODS

Sixty-six patients undergoing hemodialysis received a complete ophthalmologic examination. The state of the endothelium was assessed using pachymetry and specular microscopy. The group of patients undergoing dialysis was divided according to the time of dialysis, aluminum, product of calcium and phosphate in blood, and parathyroid hormone to analyze the influence of these factors. The possible presence of iron and aluminum in the aqueous humor of patients who underwent and those who did not undergo hemodialysis was also estimated.

RESULTS

Patients undergoing hemodialysis did not have significant corneal edema. Cell density was significantly lower in patients undergoing dialysis than in patients not undergoing dialysis; this reduction appeared to be associated with length of dialysis and was unrelated to serum aluminum and calcium levels. Patients undergoing dialysis did not have cell polymorphism or polymegethism, although there was a tendency toward increased polymegethism with length of dialysis. Aluminum and iron were not increased in the aqueous humor of patients undergoing dialysis.

CONCLUSIONS

The alteration of the endothelium that we found is not related to the elements studied. It is possibly the result of another product dissolved in the anterior chamber or to the alterations of the anterior segment that these patients are known to have.

Macrophages transfer [14C]-labelled fatty acids to pancreatic islets in culture

Macrophages are able to produce, export, and transfer fatty acids to lymphocytes in culture. The purpose of this study was to examine if labelled fatty acids could be transferred from macrophages to pancreatic islets in co-culture. We found that after 3 h of co-culture the transfer of fatty acids to pancreatic islets was: arachidonic >> oleic > linoleic = palmitic. Substantial amounts of the transferred fatty acids were found in the phospholipid fraction; 87.6% for arachidonic, 59.9% for oleic, 53.1% for palmitic, and 36.9% for linoleic acids. The remaining radioactivity was distributed among the other lipid fractions analysed (namely polar lipids, cholesterol, fatty acids, triacylglycerol and cholesterol ester), varying with the fatty acid used. For linoleic acid, a significant proportion (63.1%) was almost equally distributed in these lipid fractions. Also, it was observed that transfer of fatty acids from macrophages to pancreatic islets is time-dependent up to 24 h, being constant and linear with time for palmitic acid and remaining constant after 12 h for oleic acid. These results lead us to postulate that in addition to the serum, circulating monocytes may also be a source of fatty acids to pancreatic islets, mainly arachidonic acid.

Value of SPECT imaging of the thoracolumbar spine in cancer patients

The purpose of this study was to evaluate the usefulness of SPECT bone imaging in targeting the precise location of vertebral abnormalities to ascertain whether such knowledge would help in differentiating between metastatic and benign lesions. SPECT images of the thoracolumbar spine in 50 patients were correlated with plain x-rays, CT, MRI, PET, and bone scans and 6-month clinical follow-ups. SPECT images revealed 110 lesions, 35 of which were metastases. Twenty-four of 25 lesions involving the vertebral body with extension into posterior elements were metastases, as well as 10 of 39 lesions found in the vertebral body and 1 of 4 found in the spinous process. All lesions limited to the anterior aspect of the vertebral body (13/13), facet joints (23/23), and intervertebral disk space (6/6) were benign. In conclusion, SPECT imaging of the thoracolumbar spine is helpful in determining the precise anatomic location of vertebral abnormalities, and knowledge of the location can be used to determine whether these abnormalities in cancer patients are benign entities or metastases.

Protein reverse staining: high-efficiency microanalysis of unmodified proteins detected on electrophoresis gels

A methodology is presented for efficiently gaining structural information from electrophoresed proteins after on-gel detection by imidazole-sodium dodecyl sulfate-zinc reverse staining. As a consequence of reverse staining, (a) protein bands arise transparent against a deep white-stained background, limits of detection being in the femtomole range; (b) there is no loss of image when the gel is kept in distilled water (even during years); and (c) protein bands result immobilized, i.e., they do not diffuse upon gel storage. To recover reverse-stained proteins or fragments thereof from the gel, the immobilization of bands must first be abrogated by chelating the zinc ions from stain (protein mobilization). We had originally described mobilization at low pH by using citric acid. Here, we improve this procedure regarding the protein electrotransfer. We demonstrate that mobilization is efficiently done at neutral to alkaline pH by short-term (5 to 10 min) incubation of the gel in a buffer containing glycine or dithiothreitol prior to transfer. Moreover, mobilization was most simply performed by just adding the zinc chelating agent to the transfer buffer. Reverse staining and the new mobilization procedure made electrotransferring single protein bands from gel onto small-sized (13 x 5 mm2) PVDF membrane pieces in mini sandwich-like assemblies practical. Equipment is described for the protein electroblotting in such minisandwiches. Microsequence analysis of the electroblotted proteins showed initial yields in the range of those achieved when the transfer was done from unstained control gels. Protein bands kept in the reverse-stained gel for prolonged time periods (even for as long as 2 years) could be similarly analyzed.(ABSTRACT TRUNCATED AT 250 WORDS)

The impact of HLA mismatches on the survival of first cadaveric kidney transplants

BACKGROUND

The benefits of HLA-A, B, and DR matching of cadaveric kidney grafts and recipients remain controversial when viewed from the perspective of social equity and graft survival.

METHODS

We estimated graft survival using proportional-hazards techniques, adjusting for patient and donor characteristics, for a series of 30,564 Medicare patients receiving a first cadaveric kidney transplant between 1984 and 1990. The effects of minimal achievable HLA mismatches and maximal matching on graft survival were estimated by simulated allocation of a sample of organs to a sample of 20,000 candidates for transplantation.

RESULTS

The adjusted one-year graft survival was 84.3 percent for grafts with no mismatches and 77.0 percent for grafts with four mismatches. National rationing of donor organs to achieve minimal mismatching and maximal matching could potentially decrease the average number of HLA mismatches from 3.6 to 1.2, with a corresponding increase in the number of matches. As a consequence, projected five-year graft survival could potentially increase from 58.5 percent to 62.9 percent. This would be associated with a decrease in the proportion of kidneys allocated to black recipients from 22.2 to 15.0 percent.

CONCLUSIONS

Under ideal circumstances, a policy of maximal matching of cadaveric renal transplants would increase five-year graft survival by a comparatively small 4.4 percentage points, but the actual benefit is likely to be smaller.

Direct blotting, sequencing and immunodetection of proteins after five-minute staining of SDS and SDS-treated IEF gels with Nile red

The non-covalent dye Nile red allows the fast and simple fluorescent staining of protein bands in sodium dodecyl sulfate (SDS)-polyacrylamide gels. This procedure has been extended to polyacrylamide isoelectric focusing gels that do not contain SDS. Unlike the current methods using Coomassie blue or silver for gel staining, Nile red staining does not preclude the direct electroblotting of protein bands onto polyvinylidene difluoride membranes, and the transferred proteins can be used directly for immunoblotting analysis and for N-terminal microsequencing.

Isolation and identification of two neutral thyrotropin releasing hormone-like peptides, pyroglutamylphenylalanineproline amide and pyroglutamylglutamineproline amide, from human seminal fluid

Two tripeptide amides with stuctures similar to thyrotropin releasing hormone were isolated from human seminal fluid and their amino acid sequences determined. The peptides were purified by gel exclusion from Sephadex G50 and were detected by radioimmunoassay with thyrotropin releasing hormone antibody; in addition, N-terminally extended forms were demonstrated by radioimmunoassay after trypsin digestion. Further purification of the tripeptides was by chromatography on SP-Sephadex C25 and by high performance liquid chromatography on C18 Microbondapak using an HCl/acetonitrile gradient. After exclusion from mini-columns of SP-Sephadex C25 and DEAE-Sephadex A25, two neutral peptides were obtained in homogeneous form by high performance liquid chromatography with an HCl/methanol gradient. Amino acid analysis gave the following compositions: Glu, 0.74, Phe, 1.0, Pro, 1.0; and Glu, 1.72, Pro, 1.0. Both peptides possessed a blocked N terminus, but after opening the pyroglutamyl ring the sequences Glu-Phe-Pro and Glu-Glx-Pro were demonstrated. The chromatographic properties of the endogenous peptides were identical to the properties of the corresponding synthetic peptides. The structure of pGlu-Phe-Pro (where p-indicates pyro-) amide was confirmed by fast atom bombardment mass spectrometry. The presence in human semen of three structurally related peptides, pGlu-Phe-Pro amide, pGlu-Gln-Pro amide, and the previously reported pGlu-Glu-Pro amide (Cockle, S. M., Aitken, A., Beg, F., and Smyth, D. G. (1989) J. Biol. Chem. 264, 7788-7791), suggests that this series of peptides may have evolved to fulfil complementary biological roles.

Phospholipase production in morphological variants of Candida albicans

The yeast Candida albicans is considered a dangerous opportunist in a compromised host. Both phases of growth are thought to be pathogenic, however, evidence suggests that the hyphal phase is the more virulent. It has been proposed that the increased virulence lies in the ability of hyphae to digest and penetrate host tissue, thus enabling access of fungal cells to the deeper tissues. However, this one characteristic does not sufficiently explain the organism's success as a pathogen. Recently, high-frequency, colonial morphology switching systems were described in C. albicans. We obtained some of these variants and tested them for the ability to produce extracellular phospholipase(s), a generally accepted mechanism of pathogenesis in many microorganisms. Using egg yolk agar plates, we showed that all variants produced the enzyme. However, one produced significantly more than the others.

The impact of nonidentical ABO cadaveric renal transplantation on waiting times and graft survival

Blood type O recipients of cadaveric renal transplants have longer pretransplant waiting periods than blood type A, B, and AB recipients. To evaluate reasons for and consequences of this discrepancy, we studied both the frequency of various donor and recipient blood type combinations and their outcomes. Among 37,659 cadaveric renal transplants performed during 1983 through 1989, there were 2,625 transplants (7%) received by patients of compatible but nonidentical blood types. Of 18,575 type O donor organs, 16,784 were received by type O patients for a recipient to donor ratio of 0.9. The corresponding ratios were greater than 1.0 for all other blood types (1.02 for blood type A, 1.14 for type B, and 2.18 for type AB). This causes blood type O patients to have a lower access to transplantation and to have significantly longer waiting times than patients of all other blood types. This inequality of access diminished significantly (P less than 0.001) over the years, but did not resolve by 1989. Analysis of relative risk for first graft loss by multiple regression (Cox) showed that transplantation across compatible blood types had a 9.1% higher risk (P less than 0.1) than that of transplantation among identical blood types. Cadaveric renal transplantation within identical blood types optimizes access to transplantation and avoids further aggravating past disadvantages for blood type O recipients.

Prevalence of multiple sclerosis in Lanzarote (Canary Islands)

In the island of Lanzarote of the Province of Las Palmas, which is part of the Spanish archipelago of the Canary Islands, the prevalence of multiple sclerosis is 15 per 100,000. The prevalence of MS in Lanzarote seems related more to ethnic conditions than to geography.

Genetic analysis of muscle development in Drosophila melanogaster

The different thoracic muscles of Drosophila are affected specifically in the mutants: stripe (sr), erect wing (ewg), vertical wings (vtw), and nonjumper (nj). We have tested the extent of this specificity by means of a genetic analysis of these loci, multiple mutant combinations, and gene dosage experiments. A quantitative, rather than a qualitative, specificity is found in the mutant phenotypes. All muscles are altered by mutations in any given gene, but the severity of these alterations is muscle specific. The locus stripe seems to have a polar organization where different allelic combinations show quantitative specificity in the muscle affected. In addition to the muscle phenotypes, neural alterations are detected in these mutants. The synergism found between ewg, vtw and ewg, sr as well as the dosage effect of the distal end of the X chromosome upon the expression of ewg and sr suggests the existence of functional relationships among the loci analyzed.