PubMed · 398678
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G Mondragon, F Nygaard. 1979. Shakes, bubbles, slides, and artifacts.. https://doi.org/10.1097/00000372-197900120-00010
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Renal weight (left-right combined), as a parameter of renal development, is required to be less than half the normal value for age for a statistically confident diagnosis of hypoplasia. "Medullary ray glomerular counting" (MRGC), counting cortical glomerular generations, has been proposed as a simple technique of possibly greater sensitivity. Recent development of the Disector method for the unbiased stereological estimation of total glomerular number has provided a, hitherto unavailable, "golden standard" with which to determine the diagnostic potential of MRCG. Both "true" (actual number of generations seen) and "assumed" (a subjective "guess" of the total number of generations) MRGC counts were determined in 11 pairs of kidneys from spontaneously aborted, normally developed, non-malformed fetuses (gestational age: 15-40 weeks). Each kidney was randomly analysed blind and on two separate occasions by two paediatric pathologists using a written protocol. Results were compared with unbiased stereological estimates of glomerular number. Intra- and inter-observer and intra- and inter-(left-right)renal reproducibility were analysed. In conclusion, MRGC, using "real" counts, is a highly reproducible parameter of renal development from 15-36 weeks' gestation. Sensitivity for detection of both hypoplasia and maturation delay increase with gestational age and generally exceeds that of renal weight.
In an effort to improve working conditions in the histopathologic laboratory, we have investigated whether less toxic substances may be substituted for the toxic organic solvent xylene currently in use. Xylene is used in the clearing as well as the deparaffinization process. We have tested whether the substitution of xylene by olive oil and coconut oil leads to any difference in the quality of the histologic sections. Two tissue blocks from each of 232 specimens sent for histopathologic evaluation were subjected to parallel processing in xylene and oil. The specimens represented a broad spectrum of tissue types. All sections were stained with hematoxylin-eosin to permit evaluation of histologic and cytologic details. Furthermore, a range of histochemical and immunohistochemical stainings were applied to a subgroup of tissue sections. The results showed qualitative differences between xylene-processed and oil-processed tissue in only a minority of cases. In no cases were the oil-processed samples considered less suitable for histologic diagnosis. In the histochemical and immunohistochemical stainings, no differences were registered. Although the long-term stability of oil-processed tissue remains to be clarified, we conclude that less toxic vegetable oil may probably be substituted for xylene without losing valuable diagnostic information.
A method is presented for histological examination of undecalcified ground sections of tooth roots affected with periodontal disease. The roots were placed in Karnovsky's fixative overnight, postfixed in 2% buffered osmic acid, and dehydrated in an ascending series of ethanol. The specimens were then infiltrated with propylene-oxide and Epon-Araldite resin, embedded in Epon-Araldite, and sections were prepared using a cutting and grinding system. The resulting ground sections were 8-12 microns thick. The sections were allowed to air dry at room temperature. When thoroughly dried, a coverglass was applied using resinous mounting medium DPX. The specimens were examined by phase-contrast microscopy. The method is useful for simultaneous examination of mineralized dental tissue and bacterial morphotypes covering the root surface of teeth involved with periodontal disease.