Anna-Mary Carpenter

Comparison of streptozotocin and alloxan-induced diabetes in the rat, including volumetric quantitation of the pancreatic islets

SummaryDiabetes was induced in rats with equal molar dosages of either streptozotocin or alloxan. The clinical course of the diabetes (mortality, hyperglycemia, weight loss, polydipsia, hyperphagia, polyuria, glycosuria and diabetic indices) was recorded for six weeks before the animals were sacrificed for volumetric quantitation of the pancreatic islets. No significant differences in the pancreas (islet volumes of pancreas; beta, alpha and non-granular cell volumes and vessel volumes of both islet and total pancreas) were seen between the two groups, although differences in the clinical parameters were observed. The diabetic index at three and four weeks post injection was the clinical parameter which best reflected the terminal pancreatic beta cell volume. Analysis of the scanning data adds further empirical support for the accuracy of the linear scan method of quantitation.

Permeability of the middle ear to staphylococcal pyrogenic exotoxin in otitis media

Middle ear permeability after instillation of staphylococcal pyrogenic exotoxin was studied in each of 12 cats, 6 of them with otitis media induced by obstructing their eustachian tubes. This is the first report that there is passage of toxin to the perilymph, cerebrospinal fluid and blood not only in diseased ears, but also in normal controls, 25 min and 12 h after exposure of the middle ear cavity and round window membrane to toxin. The data suggest a pathophysiological explanation for the association of otitis media and sensorineural hearing loss and/or endolymphatic hydrops; potentially both entities can be caused by exotoxins. It also documents the extraordinary capabilities of movement of staphylococcal exotoxin.

COMPONENT QUANTITATION OF TISSUE SECTIONS. I. CHARACTERIZATION OF THE INSTRUMENTS

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STUDIES OF THE MECHANISM OF THE PERIODIC ACID-SCHIFF HISTOCHEMICAL REACTION FOR GLYCOGEN USING INFRARED SPECTROSCOPY AND MODEL CHEMICAL COMPOUNDS

It has been proposed in the literature that Schiffs reagent reacts with aldehydes to form one of the following types of compounds: alkylsulfonic acids, N-sulfinic acid derivatives, or Schiff bases. Model compounds whose structures are consistent with those proposed in the literature have been synthesized and subjected to infrared analysis. Also, actual products of Schiff reagent reactions with various aldehydes have been isolated and examined using infrared spectroscopy. Comparison of the spectra of the model compounds with those of Schiff-aldehyde reaction products yielded the following conclusions: 1. The reaction of simple organic aldehydes with Schiffs reagent produces an alkylsulfonate-type reaction product. 2. The reaction of periodate-oxidized glycogen with Schiffs reagent probably involves the formation of an alklsulfonate-type compound. 3. The product of the Schiff-aldehyde reaction exists as neither an N-sulfinic acid nor a Schiff base derivative of the fuchsin molecule.

Glomerulosclerosis in Type 2 (non0insulin-dependent) diabetes mellitus: relationship to glycaemia in the University Group Diabetes Program (UGDP)

SummaryKidney tissue of acceptable quality was available from autopsies of 55 patients who had been followed prospectively for 3 to 15 years as participants in the University Group Diabetes Program, a study of vascular disease in Type 2 (non-insulin-dependent) diabetic patients. Slides were prepared for light microscopic reading by uniform histologic techniques, and then were randomly intermixed and coded with tissues identically prepared from matched nondiabetic subjects (morphologic controls). After independent review by three morphologists, the results were tabulated and assigned to one of four diagnostic groups: 1) typical diabetic nodular glomerulosclerosis; 2) mesangial changes suggestive of diabetes (diffuse lesion); 3) non-diabetic renal disease; 4) normal for age. Of the diabetic cases 31% (17 of 55) were found to show nodular glomerulosclerosis, and another 47% (26 of 55) showed suggestive changes; none of the morphologic control slides was read as showing nodular glomerulosclerosis, but some were judged to show suggestive mesangial (diffuse) changes. Although only 4 of the 17 diabetic patients with nodules had died of uraemia, many had hypertension, which may have contributed to their deaths from vascular disease. The patients with nodular glomerular changes also showed, on the average, the highest blood glucose levels during life. Type 2 diabetes in later life appears to be associated with a high risk for typical tissue changes of diabetic kidney damage, which may contribute significantly to morbidity and mortality and may be present before azotaemia and qualitative proteinuria have been recognized.

SCANNING METHODS: VOLUME QUANTITATION OF TISSUES, CELLS AND SUBCELLULAR COMPONENTS

parallels the history of the methodology. A. Volume of fresh specimens: Mea-suring volume of entire organs can be accomplished by any one of three methods. With a large amount of tissue, volume can be determined by noting the amount of water displaced after the specimen has been dropped into a known volume of water (Fig. 1). Applying Archimedes’ princil)le, volume can be obtained by subtracting the weight of tissue in water from its weight in air. Alternately, volume of tissue may be found by dividing its weight in air by its specific gravity. To obtain specific gravity, tissue is placed in successive tubes filled with a solution of known density. When the tissue neither rises nor sinks in the solution, its specific gravity is equal to that of the solution; the specific gravity of most tissues is 1.00-1.05 (40). In a study of the volume of endocrine glands, Swinyard (47) considered the last method the most accurate of the three. Often components of fresh organs can be enumerated, as Bensley (4) demonstrated, by injecting dilute solutions of supravital dyes such as neutral red or janus green which differentiate islets from acini. From these counts, he estimated not only the number of islets per unit mass but also the total number of islets in the pancreas. This technic was used by Clark (13) as well as Haist and Pugh (25). B. Indirect methods of measuring volume: After tissues ha(l been sectioned and stained, they were either traced, drawn using a camera lucida,

Infiltration of the tensor tympani and stapedius muscles in otitis media. An experimental study in the cat

A longitudinal sequential study of otitis media was done in an experimental animal (cat) using eustachian tube obstruction. Fifty animals were used. Cellular infiltration of the tensor tympani and stapedius muscles was studied in a continuum from day 1 to 6 months after inducing otitis media. We observed that there is infiltration of the connective tissue of both muscles in otitis media, and that the cellular changes follow the same pattern as that seen in the mucoperiostium and the round window of the middle ear, although to a lesser degree. In this first report of sequential changes in middle ear muscles in otitis media, clinical implications of these findings are discussed.

Computer Analysis of Pancreatic Islet Tissue

We measure the absolute or relative volume of the islets and other pancreatic tissue components using two methods each of which requires examination of cross sections. In the linear scan procedure, lengths of linear intercepts over different tissue components are used to estimate corresponding areas and volumes. In the point count method, points falling on different components are used to estimate corresponding areas and volumes.