Frank Parker

A Basic Fuchsin and Alkalinized Methylene Blue Rapid Stain for Epoxyembedded Tissue

Sections 1 μ thick of epoxy-embedded, OsO4-fixed tissues were stained with 4% aqueous basic fuchsin at 70 C for 1 min, rinsed well and destained, also at 70 C, for 1 min. A 2% aqueous methylene blue solution, alkalinized to pH 12.5 by mixing 1 N NaOH with the dye on the slide in the proportion of about 2:1, was then allowed to act for 2 min at 23-27 C. The stain was rinsed off the slide, and the preparation air dried before applying a mounting medium and cover glass. The mounting medium consisted of immersion oil sealed with epoxy household cement. Stains had not faded after 1 yr. The method is simple, rapid (total time 4-5 min), and provides sharp contrast between cellular and connective tissue components.

The esterification in vitro of free cholesterol in human and rat plasma

The transformation in vitro of the plasma free cholesterol first observed by Sperry has been further studied. The drop in free cholesterol occuring on the incubation of rat plasma has been shown to be due to esterification by fatty acids. Radioactive cholesterol incubated in vitro in rat or human plasma becomes incorporated into each of the cholesterol ester subfractions obtained by silicic acid column chromatography. Under similar conditions of incubation no incorporation of free fatty acids into any of the plasma ester fractions has been demonstrated. However, when [14C]linoleic acid-labeled lecithin is incubated in vitro with rat or human plasma, radioactive cholesterol linoleate is formed as well as 14C free fatty acid, triglycerides, mono- and diglycerides, and probably also cephalin. Similarly, when [14C]palmitic acid-labeled tripalmitin is incubated with rat or human plasma, [14C]cholesterol palmitate results as well as 14C-labeled free fatty acid, mono- and diglycerides, cephalin and lecithin. It is concluded that the preformed fatty acid esters of the plasma are the source of the fatty acids for the cholesterol esterification reaction in vitro.

Xanthomas and hyperlipidemias

The ability to recognize diverse clinical forms of xanthomas, such as tuberous, planar, eruptive and tendinous, is important in the detection of underlying systemic disease. A variety of primary genetic disorders, as well as numerous secondary conditions such as diabetes, obstructive liver disease, thyroid disease, renal disease, and pancreatitis, can lead to hyperlipoproteinemia that results in the formation not only of xanthomas but also of life-threatening vascular atherosclerosis. An understanding of the pathogenesis of the underlying lipoprotein alterations provides a rational approach to therapy utilizing dietary manipulations and drugs. Such treatment is capable of correcting most disorders of lipid metabolism, and, if appropriate therapy is initiated at the first sign of xanthoma evolution, it may prevent progression of atherosclerosis, provide resolution of xanthomas, and in some instances prevent serious pancreatitis.

Evidence for the chylomicron origin of lipids accumulating in diabetic eruptive xanthomas: a correlative lipid biochemical, histochemical, and electron microscopic study.

Plasma lipoprotein alterations in nine insulin-dependent diabetics with hyperlipemia have been related to the lipid accumulating in eruptive xanthomas evolving in these patients. Histochemical and electron microscopic examination of xanthomas have been correlated with the lipid analyses in order to obtain additional evidence regarding the lipoprotein origin of lipids accumulating in the lesions. Both analytical and morphologic evidence suggested that circulating chylomicrons significantly contribute to the xanthoma lipids. All the patients had large quantities of circulating triglyceriderich chylomicrons which carried approximately 70% of the triglyceride found in the plasma. The fatty acid pattern of chylomicron and xanthoma triglycerides were similar. Triglyceride constituted the major lipid found in the xanthomas when they were sampled during their eruption. These findings, take in conjunction with histochemical and electron microscopic evidence of chylomicron particles in the dermal capillary walls, support the theory that blood lipoproteins, and particularly chylomicrons, permeated the vascular walls and the triglycerides carried by these lipoproteins apparently accumulated in tissue macrophages and perithelial cells which evolved into foam cells. Initiation of appropriate therapy resulted in clearance of the chylomicronemia and a concomitant resolution of the xanthomas as reflected by a decrease in total xanthoma lipid. Sequential studies of resolving xanthomas in five patients revealed that xanthoma triglyceride was mobilized more rapidly than cholesterol, resulting in a redistribution of the xanthoma lipids, so that the resolving lesions were cholesterol rich. Consistent with this change in lipid composition, correlative electron microscopy revealed loss of amorphous material from many of the foam cell vacuoles.

Glucagonoma syndrome: In vitro evidence that glucagon increases epidermal arachidonic acid

A 63-year-old white woman with perioral dermatitis, a sore tongue, and an erythematous dermatosis in the inframammary and perineal regions underwent surgical removal of a pancreatic glucagonoma. The patients plasma and pooled normal human plasma containing Sigma glucagon were fed to human keratinocyte cultures and increased arachidonic acid levels by 300% and 200%, respectively, when compared to pooled normal human plasma with no added commercial glucagon. These experiments suggest that glucagon may increase inflammatory mediators such as arachidonic acid and its metabolites in the epidermis, causing the skin lesions seen in the glucagonoma syndrome.

Ketoconazole in griseofulvin-resistant dermatophytosis

The efficacy of ketoconazole was evaluated in twenty patients with chronic dermatophyte infections who had failed to clear with griseofulvin therapy. Trichophyton rubrum was the causative organism in nineteen of the patients, and Trichophyton mentagrophytes in one patient. Three of twelve organisms tested showed in vitro resistance to griseofulvin. Duration of infection ranged from 2 to 28 years. Patients received 200 to 400 mg of ketoconazole daily for periods up to 8 months. In addition, patients were followed for 5 months post-therapy to monitor recurrences. Clearing was seen clinically as early as 2 weeks, and by 18 weeks all patients showed marked improvement or clinical clearing, though only six achieved complete mycologic cure. Improvement followed a predictable sequence of sites, with lesions of the trunk healing first, followed by hands, feet, and finally, nails. After 8 months, though all patients showed proximal nail clearing, onychomycosis persisted in thirteen of twenty affected sites. By 5 months post-therapy, four of six patients who had achieved clearing of skin and nails showed recurrences. No significant side effects were observed during therapy, though rare, apparently idiosyncratic cases of hepatotoxicity have been reported. Ketoconazole is an affective therapeutic agent for griseofulvin-resistant dermatophytosis. Apparent cures may subsequently recur after discontinuation of therapy.

In Vitro Studies of Phospholipid Synthesis in Experimental Atherosclerosis: Possible Role of Myo-Intimal Cells

Using in vitro techniques and labeled linoleic acid and glucose, alterations in phospholipid synthesis in the aorta were correlated with electron microscopic studies at various intervals of time after feeding rabbits cholesterol. After 4 to 8 weeks of feeding, more phospholipid precursors were incorporated into the phospholipids of atherosclerotic blood vessels than of normal vessels. Concomitant with the metabolic alterations, the following ultrastructural changes occur. Smooth muscle cells of the plaque (myo-intimal cells) evolve into highly vacuolated cells containing a profusion of cytoplasmic organelles. The increase in membranous organelles suggests that the increase in phospholipid synthesis may be the result of a cellular requirement for increased intracytoplasmic structural phospholipid.

Diet-Induced Systemic Lupus Erythematosus (SLE) in Primates

Ten adult, female cynomolgus macaques were randomly assigned to two equal groups: (1) semipurified diet (SPD); and (2) SPD with 45% ground alfalfa seed (AS). Both groups were studied at monthly intervals after 5 mo on their respective diets. Control animals had a mean hematocrit (Hct) of 43 +/- 2%, negative antiglobulin (AG), antinuclear antibody (ANA) and LE cell tests. Mean values for C3 and C4 were 309 +/- 47 mg/dl and 35 +/- 7 mg/dl, respectively. Mean serum binding to radiolabeled double stranded deoxyribonucleic acid (dsDNA) was 1.9 +/- 0.2%. Three of five animals fed AS developed signs of an SLE-like illness characterized by AG-positive anemia (lowest Hct 30%), positive ANA (highest titer greater than 1:15, 360; rim pattern) and elevated anti-dsDNA binding (highest 96%) with variable degrees of hypocomplementemia. One animal had granular deposition of immunoglobulin and complement at the dermal-epidermal junction of clinically normal skin the presence of immune complex-induced glomerulonephritis.

THE ENZYMATIC NATURE OF PHOSPHOLIPID SYNTHESIS IN NORMAL RABBIT AND HUMAN AORTA. RESULTS OF IN VITRO STUDIES.

Evidence has been presented to show that phospholipids are synthesized by supernatants of homogenates of rabbit and human aorta when palmitate-l-C-14, or linoleate-l-C-14, are used. The synthetic process is enzymatic in nature; it depends on temperature, pH, and the presence of various cofactors. These requirements are not unlike those of cellfree liver preparations, which also synthesize phospholipids.

Occupational contact dermatitis.

Skin reactions are common in the workplace. The skin, which constantly is exposed to chemicals and industrial processes, develops inflammatory reactions, most commonly dermatitis, which may have an allergic or irritant basis. The epidemiology, pathophysiology, and clinical features of common occupational dermatoses are discussed. Irritant, allergic, and urticarial contact reactions are compared, and their clinical features are outlined. Important occupational irritants and allergens, their sources, and the industries in which they most commonly are found are listed. The prognosis and therapy of these occupational reactions are examined.