A "floral" variant of nodal marginal zone lymphoma

We describe 6 cases of a specific variant of nodal marginal zone lymphoma with "floral" lymph follicles in patients ranging in age from 18 to 66 years. All 6 patients had lymphadenopathy, either local (n = 5) or systemic (n = 1), and good performance status (0), and none had fever, weight loss, or night sweating. They all underwent excisional biopsy. Histologically, all lesions had a distinctive morphology, with proliferation of medium-sized atypical lymphoid cells in the marginal zone, hyperplastic lymph follicles with enlarged germinal centers, and a thickened mantle zone. In places, folliculolysis was observed. On immunohistochemical staining, the atypical lymphoid cells showed a B-cell phenotype (CD20 +), IgM positivity in 2 of 5 cases, and negativity for CD5, CD10, CD23, CD43, bcl-6, and IgD. Polymerase chain reaction examination for immunoglobulin heavy chain in 5 cases showed monoclonality in all. Five patients did not receive adjuvant chemotherapy and had no recurrences. The patient with systemic lymphadenopathy received chemotherapy and had a complete response without relapse. This variant should be differentiated from the usual nodal marginal zone lymphoma because of its specific clinical and pathological features.     

Light and electron microscopic analyses of immediate and late tissue damage caused by radiofrequency ablation in porcine liver

Radiofrequency ablation (RFA) is an effective procedure for localized hepatocellular carcinoma. Contrast-enhanced CT depicts the ablated area as a hypoattenuated area without hepatic blood flow; however, light microscopy does not show obvious necrosis in the ablated area. We evaluated liver tissue changes after RFA by light microscopy and electron microscopy. The normal livers of three anesthetized pigs were coagulated using RFA after laparotomy. The liver was examined immediately, and 1 week after operation by light and electron microscopy. After RFA, the liver parenchyma surrounding the needle electrode was brown in color and surrounded by a red marginal zone separate from the normal liver parenchyma. Hematoxylin-eosin staining of the central area did not show cell necrosis, and the structures of liver sinusoids, liver cell cord and the nuclei of hepatocytes were preserved. However, electron microscopic examination of tissue immediately after RFA showed destruction of mitochondria of hepatocytes and fixation of sinusoidal cells. One week later, there was a large quantity of debris in the enlarged sinusoids, in addition to irreversible destruction of hepatocyte organelles. RFA of the porcine liver causes hepatocyte damage. This damage was not evident by light microscopy but clearly identified by electron microscopy.     

Source apportionment of methane escaping the subsea permafrost system in the outer Eurasian Arctic Shelf

The East Siberian Arctic Shelf holds large amounts of inundated carbon and methane (CH₄). Holocene warming by overlying seawater, recently fortified by anthropogenic warming, has caused thawing of the underlying subsea permafrost. Despite extensive observations of elevated seawater CH₄ in the past decades, relative contributions from different subsea compartments such as early diagenesis, subsea permafrost, methane hydrates, and underlying thermogenic/ free gas to these methane releases remain elusive. Dissolved methane concentrations observed in the Laptev Sea ranged from 3 to 1,500 nM (median 151 nM; oversaturation by ∼3,800%). Methane stable isotopic composition showed strong vertical and horizontal gradients with source signatures for two seepage areas of δ¹³C-CH₄ = (−42.6 ± 0.5)/(−55.0 ± 0.5) ‰ and δD-CH₄ = (−136.8 ± 8.0)/(−158.1 ± 5.5) ‰, suggesting a thermogenic/natural gas source. Increasingly enriched δ¹³C-CH₄ and δD-CH₄ at distance from the seeps indicated methane oxidation. The Δ¹⁴C-CH₄ signal was strongly depleted (i.e., old) near the seeps (−993 ± 19/−1050 ± 89‰). Hence, all three isotope systems are consistent with methane release from an old, deep, and likely thermogenic pool to the outer Laptev Sea. This knowledge of what subsea sources are contributing to the observed methane release is a prerequisite to predictions on how these emissions will increase over coming decades and centuries.

The East Siberian Arctic Shelf (ESAS) is the world’s largest and shallowest shelf sea system, formed through inundation of northeast Siberia during sea level transgression in the early Holocene. The ESAS holds substantial but poorly constrained amounts of organic carbon and methane (CH₄). These carbon/methane stores are contained in unknown partitions as gas hydrates, unfrozen sediment, subsea permafrost, gas pockets within and below the subsea permafrost, and as underlying thermogenic gas (1–3). Methane release to the atmosphere from these compartments could potentially have significant effects on the global climate (4, 5), yet there are large uncertainties regarding the size and the vulnerability toward remobilization of these inaccessible and elusive subsea carbon/methane pools. Conceptual development and modeling have predicted that warming of the ESAS system by a combination of geothermal heat and climate-driven Holocene heat flux from overlying seawater, recently further enhanced by Anthropocene warming, may lead to thawing of subsea permafrost (6, 7). Subsea permafrost drilling in the Laptev Sea, in part at the same sites as 30 y ago, has recently confirmed that the subsea permafrost has indeed come near the point of thawing (8). In addition to mobilization of the carbon/methane stored within the subsea permafrost, its degradation can also lead to the formation of pathways for gaseous methane from underlying reservoirs, allowing further methane release to the overlying water column (3, 9).Near-annual ship-based expeditions to the ESAS over the past two decades have documented widespread seep locations with extensive methane releases to the water column (3, 10). Methane levels are often found to be 10 to 100 times higher than the atmospheric equilibrium and are particularly elevated in areas of strong ebullition from subsea gas seeps (“methane hotspots”). Similarly, elevated dissolved methane concentrations in bottom waters appear to be spatially related to the thermal state of subsea permafrost as deduced from modeling results and/or geophysical surveys (7, 9). Currently, we lack critical knowledge on the quantitative or even relative contributions of the different subsea pools to the observed methane release, a prerequisite for robust predictions on how these releases will develop. An important distinction needs to be made between pools that release methane gradually, such as methane produced microbially in shallow sediments during early diagenesis or in thawing subsea permafrost, versus pools with preformed methane that may release more abruptly once pathways are available, such as from disintegrating methane hydrates and pools of thermogenic (natural) gas below the subsea permafrost. Multidimensional isotope analysis offers a useful means to disentangle the relative importance of these different subsea sources of methane to the ESAS: Stable isotope data (δ¹³C-CH₄ and δD-CH₄) provide useful information on methane formation and removal pathways, and the radiocarbon content of methane (Δ¹⁴C-CH₄) helps to determine the age and methane source reservoir (see SI Appendix, text S1 for details on these isotope systematics and typical isotopic signatures for the ESAS subsea system).Here, we present triple-isotope–based source apportionment of methane conducted as part of the Swedish–Russian–US investigation of carbon–climate–cryosphere interactions in the East Siberian Arctic Ocean (SWERUS-C3) program. To this end, the distribution of dissolved methane, its stable carbon and hydrogen isotope composition, as well as natural radiocarbon abundance signature, were investigated with a focus on the isotopic fingerprint of methane escaping the seabed to pinpoint the subsea sources of elevated methane in the outer Laptev Sea.     

Short Report

Background : Most aphasia therapists appear to assume that people with aphasia undergo psychological distress that is associated with communication problems. However, the relationship between aphasia and psychological status has not been sufficiently investigated. Aim : The aim of this study was to explore the relationship between verbal communication and psychological status in people with aphasia. Methods & Procedure : A total of 25 people with aphasia were assessed by the Observational Profile of Communication (OPC), the Questionnaire of Verbal Communication (QVC), and the Standard Language Test of Aphasia (SLTA). Two items of the OPC—Interpersonal Attitude and Emotional State—were used as measures of psychological status. Two domains of the QVC—Receptive Ability and Expressive Ability—were used as measures of verbal communication activity. The overall scoring system of the SLTA was used to rate the severity of aphasia. Correlations were calculated between the OPC and other variables, namely, Receptive Ability, Expressive Ability, the SLTA, age, and time since onset. The group effects of gender and aphasia type were examined. Outcome & Results : Interpersonal Attitude had a moderate and significant correlation with Receptive Ability, but not with Expressive Ability, the SLTA, age, and time since onset. Emotional State had moderate and significant correlations with the SLTA and time since onset, but not with Receptive Ability, Expressive Ability, and age. Gender and aphasia type did not have a significant relationship with the measures of psychological status. Conclusions : The relationship between verbal communication and psychological status was not straightforward in this small exploratory study. The severity of the communication problem in aphasic people does not necessarily appear to relate to psychological status.     

Gastric Mucosal Injury Induced by Local Ischemia-Reperfusion in Rats (Role of Endogenous Endothelin-1 and Free Radical)

We investigated the role of an endogenousvasoconstrictor peptide endothelin-1 (ET-1) and freeradicals in local gastric ischemia-reperfusion injury inrats. Local gastric ischemia was induced by clamping the left gastric artery for 15 min andreperfusion was done for 10-30 min in the presence of150 mM exogenous HCl intragastrically. Local gastricischemia and reperfusion resulted in significantmacroscopic and microscopic gastric mucosal damage togetherwith elevation of gastric tissue ET-1 concentration.Gastric tissue ET-1 was found to increase after 15 minof ischemia alone and also with 30 min of reperfusion. A novel nonpeptide endothelin receptorantagonist, bosentan, or a combination of radicalscavengers (superoxide dismutase, catalase, anddeferoxamine) both attenuated gastric mucosal injury.However, the greater protection observed with bosentan thanwith radical scavengers might reflect a preferentialrole of endothelin-1 in this type of injury.     

Rate-dependent changes in atrial action potential duration after short- duration rapid atrial pacing in humans.

The effect of rapid atrial pacing on the rate adaptation of the atrial action potential duration was studied in humans. The right atrial monophasic action potential (RAMAP) of 5 patients was recorded before and after 30 min of rapid atrial pacing. The pacing cycle length (CL) was 146 +/- 9 ms, the shortest duration at which 1:1 capture was possible. The RAMAP duration at 90% repolarization (RMAPD) was measured. CL-dependent changes in RAMAPD (CL 600 ms-CL 300 ms) before and after rapid atrial pacing were 51.8 +/- 10.7 ms and 30.8 +/- 7.6 ms (p < 0.05), respectively.     

Noninvasive diagnosis of dual AV nodal physiology in patients with AV nodal reentrant tachycardia by adenosine triphosphate test

Atrioventricular nodal reentrant tachycardia (AVNRT) is a relatively common paroxysmal supraventricular tachycardia. This study investigated whether adenosine-5'-triphosphate (ATP) injection during sinus rhythm might be useful in the noninvasive diagnosis of dual AV nodal pathways. The study group consisted of 9 patients with slow/fast AVNRT and 11 control patients without antegrade dual AV nodal physiology (DAVNP). ATP (2.5 to 30 mg, in 2.5-mg increments was injected during sinus rhythm until signs of DAVNP (> or = 50 msec increase or decrease in AH or PR interval in two consecutive beats) or > or = second-degree AV block was observed. DAVNP was diagnosed by ATP test in all 9 patients with slow/fast AVNRT. DAVNP was observed by ATP test in 3 of the 11 control patients. Thus, the test had a sensitivity of 100% and specificity of 73%. ATP test given during sinus rhythm is useful for identifying patients with dual AV nodal pathways who are prone to AVNRT.     

Functional giant parathyroid cyst with high concentration of CA19-9 in cystic fluid

A 63-year-old man was admitted to our hospital for the evaluation of hypercalcemia and anterior neck mass. Laboratory findings revealed hypercalcemia, hypophosphatemia, and hypercalciuria, as well as elevated serum levels of parathyroid hormone (PTH) and alkaline phosphatase. Computerized tomography and magnetic resonance images showed that the mass contained a cystic area. Parathyroid scintigraphy using either 99mTc-sestamibi alone or 201Tl-chloride in conjunction with 99mTc-pertechnetate for thyroid image subtraction showed uptake of the radioactivity into the cyst wall, suggesting that the mass originated from the parathyroid. Fine needle aspiration biopsy revealed that the cyst fluid was serous and bloody with extremely high concentrations of both PTH and CA19-9. The patient was diagnosed as primary hyperparathyroidism caused by parathyroid cyst and cervical exploration was performed. The cyst was dissected away along with the right lobe of the thyroid gland. After tumor removal, serum calcium and PTH levels were normalized. Histological study showed that the tumor possessed malignant potential with capsular invasion as well as moderate cellular atypia with trabecular pattern in arrangement. Parathyroid cells in the wall of the cystic tumor were immunostained positively for CA19-9, suggesting that CA19-9 in the cyst fluid was produced from the cells.