Morphologic heterogeneity along the rat inner medullary collecting duct

The qualitative and quantitative morphologic features of the cells lining the inner medullary collecting duct (IMCD) in the outer (IMCD1), middle (IMCD2) and inner (IMCD3) segments were investigated. Kidneys of male rats were fixed by in vivo vascular perfusion with glutaraldehyde and processed for light microscopy and scanning and transmission electron microscopy. The IMCD1 consisted of both principal cells and intercalated cells similar to those present in the outer medullary collecting duct. The principal cells were covered with small microvilli and a single cilium. Most of the IMCD2 and the entire IMCD3 contained one cell type (IMCD cell). When compared with the principal cells, the IMCD cells were taller, had fewer basal infoldings and a lighter staining cytoplasm containing numerous free ribosomes and small electron-dense cytoplasmic bodies in the basal region. The luminal surface was covered with prominent microvilli, but had no cilia. Morphometric analysis demonstrated that the surface density of apical and basal plasma membranes decreased from IMCD1 to IMCD3. However, because of an overall increase in tubule volume from IMCD1 to IMCD3, there were no significant differences in the absolute area of apical or basal membranes between the three segments. In contrast, the absolute area of lateral membranes increased significantly from IMCD1 to IMCD3. This study demonstrates that the IMCD1 consists of principal cells and intercalated cells similar to those in the outer medullary collecting duct, whereas the cells in most of the IMCD2 and the entire IMCD3 appear to represent a distinct and separate cell type which we choose to call the IMCD cell. Thus, both morphologic and functional heterogeneity appear to exist along the IMCD.     

Pancreatic pseudocyst simulating perinephric abscess

A case of pseudocyst of the pancreas simulating perinephric abscess is described. This condition is rare compared with most reported cases of pseudocyst causing pyelographic abnormalities by extrinsic compression. Spontaneous rupture of the pseudocyst is proposed as the mechanism by which the normally protective Gerota's fascia is penetrated.     

Effect of glycerol on local and systemic carcinogenicity of topically applied tobacco condensate

When glycerol was added to tobacco smoke condensate in acetone solvent, the topical carcinogenicity and the ability to produce epithelial hyperplasia in mice was reduced. Two doses of condensate were applied, combined with 2 concentrations of added glycerol. Age-standardized results show that glycerol reduced the incidence of tumours and malignant tumours and of hyperplasia in animals not developing skin tumours. The relative incidences of malignant tumours, benign tumours, hyperplasia and unaffected skin suggest that there is a sequential relationship (i.e. normal skin to hyperplasia to benign neoplasia to malignant neoplasia) which is impeded by glycerol. There was no systemic effect attributable to the condensate.     

In focus: (166) Ho-DOTMP in the pretransplant treatment of multiple myeloma

NeoRx STR 0303: a randomized multicenter study to compare the safety and efficacy of (166) HO-DOTMP plus melphalan to melphalan alone as conditioning for autologous peripheral blood stem cell transplant in subjects with primary refractory multiple myeloma.     

Morphologic characterization of rat taste receptor cells that express components of the phospholipase C signaling pathway

Rat taste buds contain three morphologically distinct cell types that are candidates for taste transduction. The physiologic roles of these cells are, however, not clear. Inositol 1,4,5-triphosphate (IP(3)) has been implicated as an important second messenger in bitter, sweet, and umami taste transductions. Previously, we identified the type III IP(3) receptor (IP(3)R3) as the dominant isoform in taste receptor cells. In addition, a recent study showed that phospholipase Cbeta(2) (PLCbeta(2)) is essential for the transduction of bitter, sweet, and umami stimuli. IP(3)R3 and PLCbeta(2) are expressed in the same subset of cells. To identify the taste cell types that express proteins involved in PLC signal transduction, we used 3,3'diaminobenzidine tetrahydrochloride immunoelectron microscopy and fluorescence microscopy to identify cells with IP(3)R3. Confocal microscopy was used to compare IP(3)R3 or PLCbeta(2) immunoreactivity with that of some known cell type markers such as serotonin, protein gene-regulated product 9.5, and neural cell adhesion molecule. Here we show that a large subset of type II cells and a small subset of type III cells display IP(3)R3 immunoreactivity within their cytoplasm. These data suggest that type II cells are the principal transducers of bitter, sweet, and umami taste transduction. However, we did not observe synapses between type II taste cells and nerve fibers. Interestingly, we observed subsurface cisternae of smooth endoplasmic reticulum at the close appositions between the plasma membrane of type II taste cells and nerve processes. We speculate that some type II cells may communicate to the nervous system via subsurface cisternae of smooth endoplasmic reticulum in lieu of conventional synapses.     

The effect of nuchal cord on amniotic fluid and cord blood erythropoietin at delivery

OBJECTIVE: We investigated the effect of a nuchal cord on fetal hypoxia by using amniotic fluid and cord blood erythropoietin as markers of chronic and acute hypoxia, respectively. METHODS: A total of 167 full-term pregnancies without maternal complications or fetal prelabor complications except fetal growth restriction of unknown cause were studied prospectively. Of these, 47 had a nuchal cord at delivery, and 62 had one or more complications during labor and delivery (nonreassuring fetal heart rate pattern, birth weight less than 2500 g, Apgar score at 1 minute less than 7, presence of meconium-stained amniotic fluid, oligohydramnios), and 26 had both nuchal cord and at least one of the intrapartum complications. RESULTS: Erythropoietin levels (mean +/- standard error of the mean) were not significantly different between the nuchal cord group (n = 47) and the no nuchal cord group (n = 120) in either amniotic fluid (19.3 +/- 4.1 mU/mL versus 13.7 +/- 1.1 mU/mL) or cord blood (57.9 +/- 10.3 mU/mL versus 52.1 +/- 4.9 mU/mL). Similarly, in the 62 fetuses with intrapartum complications, there were no significant differences in amniotic fluid (14.3 +/- 2.0 mU/mL versus 18.8 +/- 2.9 mU/mL) or cord blood erythropoietin (66.9 +/- 16.8 mU/mL versus 72.6 +/- 12.6 mU/mL) levels between those with (n = 26) or without a nuchal cord (n = 36). Among the 107 uncomplicated cases, however, amniotic fluid erythropoietin was significantly elevated in the nuchal cord group (25.5 +/- 8.7 mU/mL, n = 21) compared with that in the no nuchal cord group (11.5 +/- 0.9 mU/mL, n = 84) (P <.05), whereas there was no significant between-group difference in cord blood erythropoietin levels between nuchal cord and no nuchal cord groups (46.8 +/- 10.0 mU/mL versus 43.3 +/- 4.1 mU/mL). Tightness of the nuchal cord did not affect amniotic fluid or cord blood erythropoietin concentrations. CONCLUSION: Although nuchal cord may not significantly increase the risk of acute or labor-associated fetal hypoxia, it appears to be an independent risk factor of mild, chronic, prelabor fetal hypoxia.