Testicular tumors: clinically relevant histological findings

Testicular germ cell neoplasms affect young men in the prime of life. Although the overwhelming majority are malignant, they are curable. In addition to the stage of the disease and the presence of serum markers, there are important pathological changes that have clinical significance. These include (1) the cell type, (2) the amount of the component, and (3) the presence or absence of vascular invasion. Pure embryonal carcinoma or embryonal carcinoma in excess of 80% in a mixed tumor and vascular/lymphatic invasion are high-risk factors as they are predictors of relapse. These factors should be recognized by the pathologist and should be taken into account by the oncologist when selecting the management of a patient with a germ cell tumor of the testis.     

RSB-D 401自调匀整并条机评析

Rieter(立达)RSB-D 401自调匀整并条机(图1)显著提升了纺纱厂的质量标准,并由此创建了一套新标准.高且特别稳定的质量以及对后道工序中运行性能实质性的改善使纺纱厂能快速收回投资.     

Genetic diversity of feline immunodeficiency virus: dual infection, recombination, and distinct evolutionary rates among envelope sequence clades

For the rapid genetic analysis of feline immunodeficiency virus (FIV), we developed a heteroduplex mobility assay (HMA) that utilizes a PCR-amplified fragment of the FIV envelope gene spanning the third and fourth variable regions of the envelope surface protein coding sequence. Viral sequences were successfully amplified from blood specimens from 98 naturally infected cats from Australia, Canada, Germany, Italy, South Africa, and the United States. Eighty were clearly assignable to the A or B envelope sequence subtypes. Three belonged to subtype C, one was dually infected with viruses harboring the A and B env subtypes, and several were categorized as outliers to any of the established subtypes or as probable intersubtype recombinants. Some geographic clustering was evident, with subtypes A and B found in greater frequency in the western and eastern regions of the United States, respectively. Subtypes A, B, and C were found on more than one continent, and countries with more than two samples analyzed contained at least two subtypes. The broadest representation of subtypes was found in Munich, Germany, where three subtypes and one virus that was not classifiable by HMA were found. Thirteen samples were selected for DNA sequence determination over the same region of env used for HMA. Analysis of all available FIV env sequences from this and previous studies revealed the existence of recombinant viruses generated from subtype A/B, B/D, and A/C envelope gene sequences. Subtype A env sequences were less diverse than subtype B sequences, although both groups had well-supported clusters. Furthermore, the mutational pattern giving rise to diversification in the two subtypes differed, with the subtype A viruses showing half as many synonymous site mutations compared to subtype B yet showing similar levels of nonsynonymous site changes. These results are consistent with the hypothesis that FIV-B is an older virus group and is possibly more host adapted than FIV-A.     

Experience in conducting course exams on assignments in test form

Analysis of the results of examinations in oral surgery making use of tests in 319 fourth-year students showed that such a method of assessing students' knowledge is highly objective.     

In vitro evolution of horse heart myoglobin to increase peroxidase activity

Random mutagenesis and screening for enzymatic activity has been used to engineer horse heart myoglobin to enhance its intrinsic peroxidase activity. A chemically synthesized gene encoding horse heart myoglobin was subjected to successive cycles of PCR random mutagenesis. The mutated myoglobin gene was expressed in Escherichia coli LE392, and the variants were screened for peroxidase activity with a plate assay. Four cycles of mutagenesis and screening produced a series of single, double, triple, and quadruple variants with enhanced peroxidase activity. Steady-state kinetics analysis demonstrated that the quadruple variant T39I/K45D/F46L/I107F exhibits peroxidase activity significantly greater than that of the wild-type protein with k1 (for H2O2 oxidation of metmyoglobin) of 1. 34 x 10(4) M-1 s-1 ( approximately 25-fold that of wild-type myoglobin) and k3 [for reducing the substrate (2, 2'-azino-di-(3-ethyl)benzthiazoline-6-sulfonic acid] of 1.4 x 10(6) M-1 s-1 (1.6-fold that of wild-type myoglobin). Thermal stability of these variants as measured with circular dichroism spectroscopy demonstrated that the Tm of the quadruple variant is decreased only slightly compared with wild-type (74.1 degreesC vs. 76.5 degreesC). The rate constants for binding of dioxygen exhibited by the quadruple variant are identical to the those observed for wild-type myoglobin (kon, 22.2 x 10(-6) M-1 s-1 vs. 22.3 x 10(-6) M-1 s-1; koff, 24.3 s-1 vs. 24.2 s-1; KO2, 0.91 x 10(-6) M-1 vs. 0.92 x 10(-6) M-1). The affinity of the quadruple variant for CO is increased slightly (kon, 0.90 x 10(-6) M-1s-1 vs. 0.51 x 10(-6) M-1s-1; koff, 5.08 s-1 vs. 3.51 s-1; KCO, 1.77 x 10(-7) M-1 vs. 1.45 x 10(-7) M-1). All four substitutions are in the heme pocket and within 5 A of the heme group.     

Transurethral endoscopic electrovaporization in the treatment of patients with benign prostatic hyperplasia

The adenoid tissue is an immunecompetent lymphoid organ, which has the capacity of reacting against numerous antigens. We have studied the influence that the elimination of the said tissue would have on the total IgE serum levels in 33 patients of an average age of 5 and criteria of adenoidectomy and in whom these levels were measured before and after surgery. We have not noticed any statistically significant differences in the IgE values after adenoidectomy with respect to those prior to surgery, which were normal. Adenoidectomy, like other authors have observed after tonsillectomy, does not alter the IgE serum values.     

Ion channels in isolated mouse jejunal crypts

The patch-clamp technique was used to characterise the ion channels in cells located in the mid region of mouse jejunal crypts. Six different channels were seen. A large outwardly rectified K+ channel (BK) (conductance, g at 0 mV = 92 +/- 6 pS), which was highly selective for K+ [PK+ (1) > PRb+ (0.6) > PCs+ (0.09) approximately PNa+ (0.07) > PLi+ (0.04)], had a low, voltage-independent open probability (Po) in the on-cell (O/C) configuration and appeared in 66% of the patches. In inside-out (I/O) patches, this channel had a linear current/voltage (I/V) relationship (g = 132 +/- 3 pS), Po was voltage dependent and it was blocked by cytoplasmic Ba2+ (5 mmol/l). An intermediate K+ channel (IK) which was present in 49% of O/C patches, had a linear I/V (g = 38 +/- 3 pS), ran-down in O/C patches, and was not seen in I/O patches. A number of smaller channels (SC) with conductances ranging from 5 to 20 pS were seen in 16% of O/C patches. Also present in the basolateral membrane were a Cl- channel (ICOR) and a nonselective cation channel (NSCC). These channels were only seen in I/O patches. ICOR had an outwardly rectified conductance (g at 0 mV = 36 +/- 2 pS), its Po was independent of voltage and unaffected by variations in cytoplasmic Ca2+ (100 nmol/l to 1 mmol/l) or ATP (0-1 mmol/l). The NSCC had a linear conductance (20 +/- 1 pS), its Po increased with depolarisation and elevation of cytoplasmic [Ca2+] (> or = 10 micromol/l), but was reduced by cytoplasmic ATP. None of the basolateral channels described here were activated by cAMP-dependent secretagogues, although a Cl- conductance was activated. This cAMP-dependent Cl- conductance was distinct from the basolateral Cl- channel and thus is most likely located in the apical membrane.     

Increase in plasma propranolol caused by nicardipine is dependent on the delivery rate of propranolol

The influence of a single oral dose of nicardipine 30 mg on the pharmacokinetics and pharmacodynamics of propranolol 80 mg given as a conventional release formulation and as a slow release formulation was studied in two separate groups of 12 healthy volunteers. Nicardipine doubled the area under the curve (AUC) and Cmax of propranolol when given as a conventional formulation, but increased it only slightly when given as a slow release formulation. This pharmacokinetic interaction did not result in clinically relevant changes in pharmacodynamic responses. These results indicate that the enhancement of the bioavailability of propranolol by coadministration of nicardipine is dependent on the delivery rate of propranolol, suggesting that the interaction is mainly due to short-term haemodynamic effects of nicardipine leading to saturation of hepatic enzymes or functional shunting.