Permanent Mounts Of Chromosomes After 8-Oxyquinoline and Squashing

Fresh young root tips or free-hand cross sections thereof were placed in 0.002 M 8-oxyquinoline (aq.) at 10-14^oC. for 3 hours. After rinsing in water 1-2 minutes, they were soaked in N HC1 at 55^oC. for 25 minutes, rinsed again and squashed under a cover glass on a dry slide. Slide and cover glass were separated by placing in 70% alcohol and allowed to remain therein at least 0.5 hour after separation. Both slide and cover glass were passed through 50% and 30% alcohol to water and stained by the Feulgen procedure (without further hydrolysis) or with crystal violet after mordanting in 1% chromic acid overnight and washing in running water 3-4 hours. Dehydration and mounting in balsam completed the process. The smear on the slide was covered with a clean cover glass and the cover glass, bearing stained material, mounted separately.     

Improved Methods for Permanent Chromosome Preparations: Cellophane Squashes and Citric Acid Dissociation

Normally, squash preparations from prestained acetic acid softened or HCl macerated tissues are made by pressing the tissue under a coverglass (e.g. Walker 1973). When permanent slides are wanted the coverglass has to be removed sooner or later, which is only possible by hardening the squashed tissue by freezing, for example in carbon dioxide snow, or by slow diffusion of fixatives into the space between the slide and the coverglass. These methods are either expensive or time-consuming, and upon removal of the coverglass, many cells and chromosomes either are lost or are poorly preserved.     

Permanent Stained Preparations of Synovial Fluid for Detection of Calcium Compounds Using Alizarin Red S

Permanent preparations of air dried synovial fluids were prepared by staining calcium compounds with alizarin red S stain; each slide was coverslipped with Permount. Variables studied were: (a) concentration of the solution of alizarin red S, (b) pH of staining solution, (c) time of incubation in staining solution and aqueous and ethanolic content of staining solution. The staining effect of each solution was tested on calcium pyrophosphate dihydrate, calcium oxalate, apatite and monosodium urate (MSU). Of all the solutions, best results were obtained with 0.25% alizarin red S in 50% ethanol at pH 7.0 for 30 min. With this solution, the calcium-containing compounds were well stained. MSU did not stain and still preserved negative birefringence on polarizaton. Fixation of smears with ethanol served a double purpose: It fixed the slides without dissolving or removing MSU or the calcium compounds, yet it did dissolve five corticosteroids commonly used for intra-articular injection which may interfere with interpretation of compensated polarized light microscopy of synovial fluids.     

Treatment of Trillium Erectum Prior to and During Mass Production of Permanent Smear Preparations

Technics used in handling dormant plants of Trillium erectum L. prior to and during microsporogenesis are described. Normal meiosis occurs during storage of the plants at 4-6°C. Approximate times in days required for various stages of meiosis are presented. Schedules used for the mass production of aceto- or propiono-carmine smears of microsporocytes, microspores and pollen tubes are also given.     

Histologic classification and differential diagnosis of mesothelioma.

Controversy surrounds the diagnosis, classification, and therefore the epidemiology of those tumors which have been designated as mesotheliomas. The group includes lesions which are as broadly different as benign fibrous lesions which some authors refer to as fibromas and anaplastic tumors which are extremely difficult to differentiate from peripheral lung cancers. The former are benign tumors which are usually readily resected and therefore cured. The latter are unresectable tumors which are invariably fatal and which may terminate with extensive metastatic disease. The reasons for including all of these lesions under the category of mesothelioma and the differential diagnosis of the various types is discussed.     

Histologic and biochemical identification and characterization of an elastin in cartilage.

Histochemical and chemical techniques have been used to identify, isolate and characterize elastin from certain bovine cartilages. The results strongly suggest that in addition to fibroblasts and smooth muscle cells, chondroblasts also synthesize elastin. Some of the possible functions of elastin in elastic cartilages are discussed and the possiblity of a new type of elastin perhaps unique to cartilage is suggested.     

Comparison of Agar and Agarose Preparations for Mengovirus Plaque Formation

An agarose overlay yielded mengovirus plaques earlier and in greater size and number than overlays of chemically undefined agars with or without enhancers. Marked variability in plaque-forming efficacy of commercial agarose preparations was noted.