Abortive neovascular outgrowths discovered during vitrectomy for diabetic vitreous haemorrhage

Abortive neovascular outgrowths from the retina were identified in 13 out of 34 eyes (38%) undergoing vitrectomy for diabetic vitreous haemorrhage. Postoperatively, fluorescein angiography of the lesions demonstrated a characteristic smoke-stack pattern of dye leakage. Each outgrowth appears to represent a focal variant of preretinal neovascularisation complicating retinal capillary non-perfusion and inner retinal ischaemia, their distinctive features being determined primarily by the absence of a cortical vitreous scaffold on the retinal surface at the time of vasoproliferation.     

Advances in liquid chromatography and related methodologies for therapeutic drug monitoring

In this article the merits of current liquid chromatography (LC) columns and techniques are reviewed, to include the following topics: (1) a brief introduction to rational therapeutic drug monitoring (TDM) to justify drug measurements; (2) selected recent survey results from the College of American Pathologists (CAP) to establish the current utilization pattern of LC for TDM in the USA; (3) LC analyses of major classes of drugs--antiarrhythmics, antidepressants, antiepileptics, antimicrobials, cyclosporine, and others--with emphasis on analysis of these drugs in human serum or plasma, by focusing on the less usual, reversed-phase functional groups such as CN and phenyl, and by the use of "mini" columns, silica and polymeric columns, the emphasis being reduced on the well-established C-18 columns; (4) high-speed LC; (5) various approaches of direct sample analysis--solvent extraction, automated sample processing, column switching, micro-injections, micellar chromatography, electrochemical detection with photolytic derivation, and the internal surface reversed-phase column of Pinkerton; (6) microbore LC drug analysis; (7) clinical chiral separation; and (8) overall conclusions.     

Trisomy 22 in acute myeloid leukemia: a marker for myeloid leukemia with monocytic features and cytogenetically cryptic inversion 16

Trisomy 22 is an uncommon chromosomal abnormality in acute myeloid leukemia. Recent studies, however, have shown an association between trisomy 22 and acute myeloid leukemia with a monocytic component, and in particular, acute myelomonocytic leukemia with marrow eosinophilia. Furthermore, it has also been suggested that trisomy 22 was in fact only a secondary chromosomal change occurring in acute myeloid leukemia with inv(16). In this report, we analyze the morphological, cytogenetic, and molecular findings of three cases of acute myeloid leukemia with trisomy 22 but without cytogenetic evidence of inv(16). The results indicate a consistent association between trisomy 22 and inv(16), the latter being cytogenetically cryptic in some cases. This finding is of potential diagnostic and therapeutic significance.     

Comparison of the COBAS TaqMan HBV test with the COBAS Amplicor monitor test for measurement of hepatitis B virus DNA in serum

Quantitation of low hepatitis B virus (HBV) DNA levels in patients with chronic hepatitis B is important for monitoring natural history of disease and treatment efficacy. This study aimed to compare the quantitation range and analytical sensitivity of the newly developed COBAS TaqMan HBV test (TaqMan test) with the COBAS Amplicor HBV Monitor Test (Amplicor test), using the Eurohep HBV reference plasma and serum samples from patients. Serial dilutions (2.7x10(1)-2.7x10(8) copies/ml) of the Eurohep HBV reference plasma and 50 serum samples from chronic hepatitis B patients were tested by both assays. The TaqMan test could detect seven (2.7x10(2)-2.7x10(8) copies/ml) of eight dilutions of the reference plasma, while the Amplicor test could only detect three of them (2.7x10(3)-2.7x10(5) copies/ml). The HBV DNA values measured by the TaqMan test correlated very well with the theoretical Eurohep standard values (r=0.998, P<0.001). There were good correlations between the HBV DNA levels measured by the two assays on both the Eurohep reference plasma (r=0.993, P<0.001) and serum samples from patients (r=0.904, P<0.001). Compared to the Amplicor test, the TaqMan test had a higher sensitivity (50 vs. 300 copies/ml), shorter assay time (6 vs. 10 hr), and wider dynamic range (8 vs. 3 logs), and was more cost-effective in a clinical setting. These data indicate that the TaqMan test is an excellent tool for HBV DNA quantitation.     

Importance of the superficial tissue layer for the indentation stiffness of articular cartilage

Indentation testing is a widely used technique for nondestructive mechanical analysis of articular cartilage. Although cartilage shows an inhomogeneous, layered structure with anisotropic mechanical properties, most theoretical indentation models assume material homogeneity and isotropy. In the present study, quantitative polarized light microscopy (PLM) measurements from canine cartilage were utilized to characterize thickness and structure of the superficial, collageneous tissue layer as well as to reveal its relation to experimental indentation measurements. In addition to experimental analyses, a layered, transversely isotropic finite element (FE) model was developed and the effect of superficial (tangential) tissue layer with high elastic modulus in the direction parallel to articular surface on the indentation response was studied. The experimental indentation stiffness was positively correlated with the relative thickness of the superficial cartilage layer. Also the optical retardation, which reflects the degree of parallel organization of collagen fibrils as well as collagen content, was related to indentation stiffness. FE results indicated effective stiffening of articular cartilage under indentation due to high transverse modulus of the superficial layer. The present results suggest that indentation testing is an efficient technique for the characterization of the superficial degeneration of articular cartilage.     

The effect of metal ions and antidiuretic hormone on oxygen consumption in toad bladder

1. The sodium-dependent oxygen consumption of pieces of toad bladder (Bufo marinus) has been investigated using an oxygen electrode.2. The effect of polyvalent cations (Ca(2+), Sr(2+), Mg(2+), Eu(3+), La(3+) and Mn(2+)) on sodium-dependent oxygen consumption has been measured. All cations inhibited oxygen consumption, the order of effectiveness being Ca(2+) > Sr(2+) > Mg(2+) > Mn(2+) > Eu(3+) > La(3+).3. Treatment of bladder pieces with antidiuretic hormone (50 m-u./ml.) decreased the effectiveness of Ca(2+) and Sr(2+) as inhibitors of sodium-dependent oxygen consumption. Mn(2+), Eu(2+) and La(2+) were more effective after hormonal treatment, while the effectiveness of Mg(2+) was unaltered.4. The results have been interpreted in terms of a model in which sodium entry to the transporting mechanisms of the epithelium is controlled by Ca(2+), and in which antidiuretic hormone alters Ca(2+) binding and so affects sodium transport.     

WSJM, a simple chemically defined medium for growth of Neisseria gonorrhoeae

The growth requirements of 135 clinical isolates of Neisseria gonorrhoeae and six American Type Culture Collection reference strains were examined by using a simple chemically defined medium known as Wong-Shockley-Johnston medium, WSJM. The simple liquid medium supported growth of gonococci from an inoculum of 2 X 10(6) colony-forming units ml-1 and yielded 10(10) colony-forming units ml-1 in 10 h in the absence of CO2. Scale-up experiments with the complete medium yielded 5 to 10 g, wet weight, of cells per liter. The complete medium was stable upon storage at 5 degrees C and after lyophilization.     

Increased expression of osteopontin gene in atypical teratoid/rhabdoid tumor of the central nervous system.

The atypical teratoid/rhabdoid tumor, primary to the central nervous system, is a highly malignant and aggressive neoplasm of infancy and childhood. Although having distinct biological features and clinical outcomes, it is frequently misdiagnosed as primitive neuroectodermal tumor/medulloblastoma. To further distinguish the underlying pathogenesis and to identify biological markers for clinical use, an atypical teratoid/rhabdoid tumor-derived cell line was established and its gene expression pattern analyzed in comparison to the human astrocyte SVG12 cell line and the human DAOY medulloblastoma cell line using a complementary DNA microarray method. The osteopontin gene was found specifically upregulated in atypical teratoid/rhabdoid tumor cells. This specificity was confirmed by immunohistochemistry in pathological sections of tissues from atypical teratoid/rhabdoid tumor patients. Even though the role of osteopontin in the cytopathogenesis of atypical teratoid/rhabdoid tumor still needs to be determined, our data support that overexpressed osteopontin is a potential diagnostic marker for atypical teratoid/rhabdoid tumor.