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Microsatellite data have recently been introduced in the context of genetic maternity and paternity assignments in high-fecundity fish species with single-parent-tended broods. Here we extend such analyses to an aquatic invertebrate, the crayfish Orconectes placidus, in which gravid females carry large numbers of offspring. Genetic parentage analyses of more than 900 progeny from 15 wild crayfish broods revealed that gravid females were invariably the exclusive dams of the offspring they tended (i.e. there was no allomaternal care), and that most of the females had mated with multiple (usually two) males who contributed sometimes highly skewed numbers of offspring to a brood. Within any multiply sired brood, the unhatched eggs (or the hatched juveniles) from different fathers were randomly distributed across the mother's brood space. All of these genetic findings are discussed in the light of observations on the mating behaviours and reproductive biology of crayfish.

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Snubnose darters comprise one of the largest subgenera of the percid genus Etheostoma. Many species are described based on differences in male breeding coloration. Few morphological synapomorphies have been proposed for the subgenus and their relatives, making it difficult to delineate monophyletic clades. The phylogenetic relationships of the 20 snubnose darter species of the subgenus Ulocentra and 11 members of its proposed sister subgenus Etheostoma were investigated with partial mitochondrial DNA sequences including 1033 bp encompassing the entire mitochondrial control region, the tRNA-Phe gene, and part of the 12S rRNA gene. Two hypotheses on the relationship and monophyly of the two subgenera were evaluated. Both maximum-parsimony and neighbor-joining analyses supported monophyly of the subgenus Ulocentra and resolved some species-level relationships. The banded darter, E. zonale, and its sister taxon, E. lynceum, were not closely related to the snubnose darters and appear to be diverged from the other members of the subgenus Etheostoma, fitting their former distinction as the recognized subgenus Nanostoma. The sister group to Ulocentra appears to be a restricted species assemblage within the subgenus Etheostoma containing E. blennioides, E. rupestre, E. blennius, and the E. thalassinum species group. The placement of the harlequin darter, E. histrio, is problematic, and it may represent a basal member of Ulocentra or of the restricted subgenus Etheostoma. Despite recent estimates of divergence times between nominal Ulocentra taxa, each species exhibits its own unique set of mtDNA haplotypes, providing no direct evidence for current genetic exchange between species. The nominal taxa of snubnose darters thus appear to be evolving independently from each other and therefore constitute valid species under the Phylogenetic Species Concept.

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Real-time spatial compound imaging (SonoCT) is an ultrasound technique that uses electronic beam steering of a transducer array to rapidly acquire several (three to nine) overlapping scans of an object from different view angles. These single-angle scans are averaged to form a multiangle compound image that is updated in real time with each subsequent scan. Compound imaging shows improved image quality compared with conventional ultrasound, primarily because of reduction of speckle, clutter, and other acoustic artifacts. Early clinical experience suggests that real-time spatial compound imaging can provide improved contrast resolution and tissue differentiation that is beneficial for imaging the breast, peripheral blood vessels, and musculoskeletal injuries. Future development of real-time spatial compound imaging will help address the bulk of general imaging applications by extending this technology to curved array transducers, tissue harmonics, panoramic imaging, and three-dimensional sonography.

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This study compares the rate and perceptions of interruptions experienced by practice nurses and GPs. During two recording periods, nurses noted the number of interruptions they experienced before and during their consultations (Paxton et al 1996). The nurses reported 48.5 interruptions per 100 consultations in the first period and 30.2 in the second. Fifty per cent of nurses in the first period and 33 per cent in the second were interrupted during consultation more than ten times per 100 consultations. Nurses reported that interruptions were distracting, affected patient flow and that the confidential nature of some consultations was irrevocably damaged by constant disturbances. It was the perception of the nurses that GPs caused most interruptions. Few patients, however, reported being disturbed as a result of an interruption to the nurse. The rate of interruptions for GPs was much lower and 94 per cent reported being interrupted during fewer than one in 20 consultations, although even then doctors reported interruptions as disruptive. Despite the decrease in interruptions to nurses in the second period of recording, the level remained much higher than that of interruptions to doctors.

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While MR is known to be superior to other imaging methods for detecting marrow involvement by lymphoma, MR is also capable of detecting abnormal lymph nodes. Our objective was to determine whether MR employing short TI inversion recovery (STIR) was comparable to CT in the initial staging of 23 patients with Hodgkin's disease (12 patients) and non-Hodgkin's lymphoma (11 patients). MR images of chest, abdomen, pelvis, and femoral marrow were obtained using the STIR and T1-weighted spin-echo (T1-SE) techniques, employing a protocol initially designed for marrow assessment. In all cases, CT-detected adenopathy was also found by MR. Four patients had marrow involvement by MR, undetected by CT. We conclude that MR and CT may be equivalent imaging modalities in the detection of nodal involvement, and that MR has an advantage in its ability to diagnose marrow involvement. Given the high frequency of focal marrow abnormalities detected by MR in patients with Hodgkin's disease and high-grade non-Hodgkin's lymphoma, MR may be the preferred staging modality for these patients.

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We reviewed magnetic resonance (MR) staging examinations of 98 patients with malignant lymphoma who failed other therapy and were under evaluation for bone marrow transplantation. MR scan results were compared with blind posterior iliac crest aspirations and biopsies. Images of vertebral, pelvic, and femoral marrow were obtained using a standard T1-weighted, short repetition time (TR), short time to echo (TE) (TR700/TE22), spin-echo (T1-SE) method in 92 patients and short TI inversion recovery (STIR) technique (TR1,500/TE36/TI100) in all. On standard T1-SE sequence, normal marrow is bright due to the predominance of marrow fat, and tumor is dark. With STIR images, water containing tumor has a very high signal intensity in a dark (fat suppressed) background. Thirteen patients had positive MR scans and marrow biopsies, whereas 49 had negative MR scans and biopsies. Of 36 discordant MR/histology results, 10 had positive biopsies and negative MR exams; eight of these had microscopic infiltration (less than or equal to 5%) with tumor. MR detected marrow tumor either in the crests or elsewhere in 25 of 75 (33%) patients with negative study biopsies. We could confirm marrow involvement in 15 of these 25 (60%) by clinical methods. Therefore, up to one third of the patients evaluated with routine biopsies may have occult marrow tumor detectable by MR exam. In patients with negative marrow biopsies, especially those with Hodgkin's disease or intermediate to high-grade non-Hodgkin's lymphomas, MR scans found focal lesions distant from the crests. Biopsy better detected lower grade microscopic involvement. We conclude that optimal marrow staging of lymphoma patients incorporates both biopsy and MR imaging.

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Ten patients with non-Hodgkin's lymphoma have been evaluated as candidates for experimental radioimmunotherapy and five of those patients have been treated with a single high dose of iodine-131-(131I) labeled anti-pan B-cell antibodies. The evaluation protocol involved collecting biodistribution data by quantitation of gamma camera images and by tumor biopsy from trace labeled doses of antibody, to estimate the relative radiation dose delivered to normal organs and tumor sites. Each patient received up to three escalating mass doses (0.5 mg/kg, 2.5 mg/kg, and 10.0 mg/kg) of radioiodinated antibody for determination of the antibody amount that yielded the most favorable biodistribution for treatment. The millicuries of 131I-labeled to the optimal antibody dose for therapy was selected to deliver 1,000 rads (three patients) or 1,500 rads (two patients) to normal uninvolved organs. Because severe bone marrow toxicity was expected, all patients had their bone marrow cryopreserved prior to entry into the study. This report details the methods and results of quantitative imaging, biodistribution data collection, and absorbed radiation dose estimation in patients with lymphoma receiving high level radioimmunotherapy with 131I-labeled antibodies.

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Three- to eight-day old Mysidopsis bahia were used to evaluate the acute toxicities of 17 industrial surfactants having a wide range of physiochemical characteristics. LC50s based on nominal concentrations covered approximately three orders of magnitude (less than 1 to greater than 4,000 mg/L). The base structure of the surfactants (i.e., aromatic or aliphatic, branched or linear) was not a factor controlling toxicity. Low solubility surfactants with low ethylene oxide (EO) molar ratios were the most toxic surfactants tested. Ethylene oxide chain length was the best predictor of toxicity, and would be a good parameter to use to "screen" for surfactant toxicity in hazard assessment. Substitution of terminal OH with SO3 or PO4 reduced toxicity of a selected group of surfactants. Sensitivity of M. bahia up to 26 days old was not significantly different from that of 3- to 8-day old animals. Use of one surfactant as a reference toxicant demonstrated that sensitivity of M. bahia was consistent throughout the various tests.

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Unenhanced T1- and T2-weighted spin-echo, short inversion time inversion recovery (STIR), and gadolinium-DTPA (Gd-DTPA)-enhanced spin-echo and STIR imaging techniques were used in 20 patients as part of a multicenter study to assess the safety and efficacy of Gd-DTPA in spinal imaging. Five patients had normal MR scans. Of those with lesions, both Gd-DTPA-enhanced T1-weighted spin-echo and unenhanced STIR scans improved detection and evaluation of spinal tumors over conventional spin-echo methods, particularly T2-weighted spin echo, by providing higher tissue contrast in shorter imaging times. The Gd-DTPA-enhanced T1-weighted spin-echo scans were most helpful in evaluating intradural tumors, whereas STIR sequences were most effective for extradural tumors and bone metastases. In most cases, Gd-DTPA-enhanced T1-weighted spin-echo scans best delineated tumor margins, and the enhancement was helpful in suggesting a cellular or active nature of the lesions. In some cases, the enhancement resulted in a more homogeneous and thus less abnormal-appearing marrow in vertebrae involved by tumor; therefore, a precontrast T1-weighted spin-echo scan is necessary in all patients who are to be studied with Gd-DTPA. A combined approach that uses T1-weighted spin-echo, Gd-DTPA-enhanced T1-weighted spin-echo, and STIR images currently appears optimal for MR imaging of spinal neoplasms. T2-weighted spin-echo images add information only in occasional cases.

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Fifteen patients with known metastatic or high-risk primary cancer, normal neurologic examinations, and new abnormalities on 99mTc bone scan were evaluated with spinal CT and magnetic resonance (MR) imaging. Four patients underwent CT metrizamide myelography. Spinal CT and MR agreed in 14 of 15 patients demonstrating spinal metastases in 12 patients and benign disease in two. In one patient spinal CT was normal, but MR showed altered marrow signal consistent with metastatic disease. Epidural tumor was demonstrated by CT metrizamide myelography in four cases, all correctly identified by MR. Further evaluation of spinal MR in this setting is warranted.

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Twenty-nine soft tissue masses were studied with magnetic resonance imaging (MRI) which proved to be useful in the preoperative evaluation of these lesions. Other imaging modalities employed had significant limitations. Plain films were of little value because of the intrinsically low contrast of soft tissues. Angiography was not necessary unless MRI suggested a vascular lesion or proximity to major blood vessels. Computed tomography (CT) and MRI both readily identified fatty lesions and their relationship to adjacent structures. Some soft tissue tumors could not be delineated from normal muscle with CT, but were easily seen with MRI. MRI is ideally suited for the study of suspected soft tissue tumors because of its excellent soft tissue contrast and its ability to image directly in any plane. Optimum evaluation required imaging in at least two planes with spin echo sequences chosen to bring out both T1 and T2 features.

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Chondrosarcoma of the head and neck region is a rarely encountered tumor. Aggressive surgical excision offers the best chance for cure. In our case, combined diagnostic techniques consisting of fine needle aspiration (FNA), computed tomography (CT), and magnetic resonance imaging (MRI) made an accurate preoperative assessment possible and greatly influenced the treatment provided.

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Hepatobiliary imaging with Tc-99m IDA derivatives has proven value for evaluation of biliary disease. Prompt hepatocellular uptake with persistent nonvisualization of the common bile duct and bowel is usually indicative of a high-grade common bile duct obstruction, but is not pathognomonic. A functional abnormality due to hepatocyte dysfunction resulting in intrahepatic cholestasis can also cause this pattern. Two cases of hepatocellular excretory dysfunction, one due to E. coli endotoxemia with intrahepatic cholestasis and the other due to acute hepatitis A that produces ductal obstructive patterns on Tc-99m disofenin scintigraphy in patients with documented patent biliary ducts, are reported. Transhepatic cholangiography or endoscopic retrograde cholangiography may be useful when the diagnosis of biliary ductal obstruction is in doubt.

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Magnetic resonance (MR) imaging, performed on 31 women with 40 surgically proven adnexal masses, was reviewed to determine whether MR can distinguish hemorrhagic from nonhemorrhagic masses. Fourteen masses proved to be hemorrhagic at surgery including functional ovarian cysts (seven cases), cystadenoma (one case), endometriomas (three cases), hematosalpinx (one case), ectopic pregnancy (one case), and parametrial extension from cervical carcinoma (one case). A high signal intensity (compared with adjacent pelvic fat) on a T1-weighted spin echo sequence was found to be a reliable indicator of hemorrhage and was demonstrated in all 14 hemorrhagic masses. The "hematocrit" effect was seen as an area of high signal intensity layering in the dependent portion of six hemorrhagic cysts. Only four of 26 nonhemorrhagic masses demonstrated high signal intensity on T1-weighted sequences and, of these, three proved to be fat-containing dermoid cysts and one was a simple cyst with adherent mesenteric fat. We conclude that high signal intensity on a T1-weighted spin echo pulse sequence is evidence for a hemorrhagic mass and that a hematocrit effect appears to be a specific sign for a hemorrhagic cyst. The clinical significance of hemorrhagic adnexal masses is discussed.

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Five patients with progressive hairy cell leukemia were treated with recombinant alpha 2-interferon and examined prospectively at 3-month intervals using serial bone marrow biopsies and magnetic resonance (MR) imaging. Pretreatment iliac crest marrow biopsies demonstrated hairy cell infiltration involving 30-90% of marrow cellularity. Concurrent pretreatment coronal images of the proximal femurs and pelvis using MR revealed extensive marrow involvement that varied in distribution from patchy to diffuse. At 6 months, all patients had responded to alpha 2-interferon with improvement in peripheral blood counts and decrease in lymphoid infiltration on marrow biopsy to 15-40%. Six-month follow-up MR scans demonstrated decreasing marrow leukemia infiltration and increasing marrow fat. MR bone marrow imaging appears useful in the initial diagnosis of hairy cell leukemia, for monitoring the response to treatment, and possibly for predicting relapse.

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