Fine-needle aspiration of pancreatic extramedullary plasmacytoma: Possible confusion with islet cell tumor

We report two cases of extramedullary plasmacytoma (EMP) of the pancreas, diagnosed by fine-needle aspiration (FNA). Plasmacytoma of the pancreas is a rare neoplasm with only 12 cases recorded in the literature. Because of its scarcity and the cytomorphologic similarity between plasma cells and endocrine cells, EMP of the pancreas may be confused with neuroendocrine (islet cell) tumors of the pancreas. Immunohistochemical staining for light chain and/or neuroendocrine markers will prevent diagnostic error when interpreting plasmacytoid neoplasms of any site susceptible to endocrine tumors, including the pancreas. © 1994 Wiley-Liss, Inc.     

A new physical assay method for tobacco mosaic virus using a radioactive virus recovery standard and the first derivative of the ultraviolet absorption spectrum

A new physical assay method for tobacco mosaic virus is described which incorporates two improvements on previous procedures. Losses of up to 75% of virus during extraction are corrected by adding a trace of radioactive virus to leaf samples before homogenization, and determining percentage recovery of radioactivity in final virus preparations. Estimation of virus concentration in partially purified preparations is from the first derivative (dA/d lambda) of the ultraviolet absorption spectrum, using a pronounced signal from the tryptophan fine-structure absorption band at 285-293 nm. This method is highly insensitive to ultraviolet-absorbing contaminants, which cause errors and increase variation between replicates, when estimation of virus concentration is by normal measurement of ultraviolet absorption (A260). The method can be applied to at least some other viruses.     

Comparison of isolation of Haemophilus vaginalis (Corynebacterium vaginale) from peptone-starch-dextrose agar and Columbia colistin-nalidoxic acid agar.

A total of 447 cervical or vaginal specimens were inoculated in parallel onto peptone-starch-dextrose (PSD) and Columbia colistin (10 mg/ml)-nalidixic acid (15 mug/ml) (CNA) agar and were incubated for 48 h at 35 degrees C in an atmosphere with 2 to 10% CO2. One hundred (22.4%) of the cultures were positive for Haemophilus vaginalis. Forty-eight of the isolates were recovered from both PSD and Columbia CNA agar, five from PSD only, and 47 from Columbia CNA agar only (P less than 0.001). On Columbia CNA agar, 76 of the isolates were detected after 24 h of incubation, and the remainder were detected within 4 days of incubation.     

Population study of T cell receptor V beta gene usage in peripheral blood lymphocytes: differences in ethnic groups.

The T cell receptor (TCR) V beta repertoire in peripheral blood lymphocytes (PBL) of a large number of healthy individuals was analysed by quantifying V beta-specific mRNA using the method of anchored multiprimer DNA amplification and a reverse dot blot assay. Among 16 V beta gene families examined, particular V beta genes were noted to be unequally expressed in the PBL of 70 healthy donors. The frequently used genes belong to the V beta 4, 5, 6, 8 and 13 (12) families, while V beta 1, 9 and 15 were the least frequently used gene families. This bias in gene usage was observed in all individuals. Marked deviation from the mean percentage usage was noted for some V beta genes in individuals when their PBL were examined serially, but the common pattern of biased usage was not grossly distorted. When the TCR repertoire of different ethnic groups was examined, a lower mean frequency of V beta 3.2 was seen in the repertoire of 19 Caucasians compared with 25 age-matched Samoans (P < 0.003). Conversely, the expression of V beta 5.1 and V beta 5.3 was higher in Caucasians than in 51 age-matched Polynesians (Maoris and Samoans, P < 0.003). Considering the 20% co-efficient of variation in the estimate of V beta gene usage, our data from 70 unrelated individuals suggest that in PBL, individual variations in the TCR repertoire were superimposed upon a common biased usage of V beta genes in the general population.     

Differential expression of stem cell mobilization-associated molecules on multi-lineage cells from adipose tissue and bone marrow

Our laboratory has characterized a population of stromal cells obtained from adipose tissue termed processed lipoaspirate cells (PLAs). PLAs, like bone-marrow derived mesenchymal stem cells (BM-MSCs), have the capacity to differentiate along the adipogenic, osteogenic, chondrogenic, and myogenic lineages, In order to better characterize these two multi-lineage populations, we examined the surface phenotype of both bone marrow and adipose tissue-derived cells from five patients undergoing surgery. PLA and BM-MSC cells were isolated, subcultivated, and evaluated for cell surface marker expression using flow cytometry. PLA and BM-MSC cells both expressed CD13, CD29, CD44, CD90, CD105, SH-3, and STRO-1. Differences in expression were noted for cell adhesion molecules CD49d (Integrin alpha4), CD54 (ICAM-1), CD34, and CD106 (VCAM-1). While markedly similar, the surface phenotypes of PLA and BM-MSC cells are distinct for several cell adhesion molecules implicated in hematopoietic stem cell homing, mobilization, and proliferation.     

Spurious hyperkalaemia

In a patient with acute lymphoblastic leukaemia, the plasma was found to have a potassium level of 10·4 mEq./1. Investigations showed that plasma from patients with leukaemia may be found to have falsely high potassium levels because of breakdown of leucocytes between the venepuncture and separation of the plasma.     

The effect of menopause on the relation between weight gain and mortality among women

OBJECTIVE: To examine the effect of menopause on the relation between weight gain and all-cause mortality. DESIGN: Prospective cohort study of 6,030 adults (ages 25-82 years) who never smoked cigarettes, had no history of coronary heart disease, cancer, or stroke, and were enrolled in a 29-year follow-up in which anthropometric data were given at baseline and at 17 years after baseline. RESULTS: Weight gain that occurred over a 17-year interval (baseline to 17 years after baseline) increased the mortality risk of men and middle-aged women, but decreased the mortality risk of older women. Further study of the women revealed that a strong protective effect of weight gains was only evident among the leanest (25 kg/m2) postmenopausal women [HR (95% CI) = 0.81 (0.41, 1.58)] or for premenopausal women [HR (95% CI) = 1.05 (0.49, 2.25) for 25 kg/m2]. We found that the protective effect of weight gain among the leanest postmenopausal women was primarily due to a more than threefold decrease in cardiovascular disease mortality risk. One possible explanation for these findings is that weight gain increases the level of adipose-tissue-derived estrogen among lean postmenopausal women. CONCLUSION: Moderate menopausal weight gain may be well tolerated in lean women.     

Rapid detection of group B streptococci in pregnant women at delivery

BACKGROUND: Group B streptococcal infections are an important cause of neonatal morbidity and mortality. A rapid method for the detection of this organism in pregnant women at the time of delivery is needed to allow early treatment of neonates. METHODS: We studied the efficacy of two polymerase-chain-reaction (PCR) assays for routine screening of pregnant women for group B streptococci at the time of delivery. We obtained anal, vaginal, and combined vaginal and anal specimens from 112 pregnant women; in 57 women, specimens were obtained before and after the rupture of the amniotic membranes. The specimens were tested for group B streptococci by culture in a standard selective broth medium, with a conventional PCR assay, and with a new fluorogenic PCR assay. RESULTS: Among the 112 women, the results of the culture of the combined vaginal and anal specimens were positive for group B streptococci in 33 women (29.5 percent). The two PCR assays detected group B streptococcal colonization in specimens from 32 of these 33 women: the one negative PCR result was in a sample obtained after the rupture of membranes. As compared with the culture results, the sensitivity of both PCR assays was 97.0 percent and the negative predictive value was 98.8 percent. Both the specificity and the positive predictive value of the two PCR assays were 100 percent. The length of time required to obtain results was 30 to 45 minutes for the new PCR assay, 100 minutes for the conventional PCR assay, and at least 36 hours for culture. CONCLUSIONS: Colonization with group B streptococci can be identified rapidly and reliably by a PCR assay in pregnant women in labor both before and after the rupture of membranes.     

DNA large restriction fragment patterns of sporadic and epidemic nosocomial strains of Mycobacterium chelonae and Mycobacterium abscessus.

Large restriction fragment (LRF) pattern analysis of genomic DNA using pulsed-field gel electrophoresis was performed on three reference strains, 32 sporadic isolates, and 92 nosocomial isolates from 12 epidemics of Mycobacterium chelonae and Mycobacterium abscessus. Only 17 of 30 (57%) unrelated strains of M. abscessus, compared with 10 of 11 (91%) of M. chelonae strains, gave satisfactory DNA extractions, with the remainder resulting in highly fragmented DNA. DraI, AsnI, XbaI, and SpeI gave satisfactory LRF patterns. Sporadic isolates of the two species had highly variable LRF patterns, except for one reference strain and one sporadic isolate of M. chelonae that differed by only two to five bands. Evaluation of repeat isolates from five patients monitored for 8 months to 13 years (mean, 5.8 years) revealed LRF patterns to be stable, with changes of not more than two bands. LRF analysis of the seven nosocomial outbreaks with evaluable DNA revealed identical patterns in most or all of the patient isolates and in three outbreaks revealed identity with environmental isolates. These outbreaks included endoscope contamination, postinjection abscesses, and surgical wound infections. LRF analysis of genomic DNA is a useful technique for epidemiologic studies of M. abscessus and M. chelonae, although improved technology is needed for the approximately 50% of strains of M. abscessus with unsatisfactory DNA extractions.     

Repertoire of transcribed peripheral blood T-cell receptor beta chain variable-region genes in acute rheumatic fever.

Patients with severe group A streptococcal infections have abnormalities in the Vbeta repertoire of peripheral blood T cells that are consistent with superantigen stimulation by cytoplasmic membrane proteins. The purpose of this study was to determine whether similar changes in Vbeta repertoire could be found for patients with acute rheumatic fever (ARF). The mean Vbeta repertoire of peripheral blood T cells in nine hospitalized ARF patients was similar to that of 34 controls and did not change during 6 months of follow-up in 6 of the ARF subjects. We were unable to detect changes in the Vbeta repertoire of peripheral blood T cells from patients with ARF that could be attributed to the influence of a superantigen.