Ultrastructural changes and viral morphogenesis during the growth of the mouse preputial gland tumor ESR 586.

A study was undertaken to observe morphological changes and viral morphogenesis during the growth of the mouse preputial gland tumor ESR 586. The acinar cells of the normal preputial gland have an extensive agranular endoplasmic reticulum and Golgi apparatus and large lipid droplets. No viral particles are present. During tumor growth, and numerous lipid droplets never attain the size of those found in the normal gland. There is a decrease in the Golgi apparatus and agranular endoplasmic reticulum and an increase in the rough endoplasmic reticulum which could reflect a change in composition of tumor secretory product from the normal gland. Indeed, there is a decrease in triglycerides as the tumor ages and an increase in the sterol esters and waxes. In addition, intracisternal A-particles are observed budding from thickened endoplasmic reticulum membranes. Thickening of these membranes occur early in A-particle formation. One side of the membrane is first thickened while the opposing membrane appears is first thickened while the opposing membrane appears morphologically unaffected. The thickening of the affected membrane is initially confined to the outer (cytoplasmic) face of the membrane. In the older tumor, both opposing membranes of the reticulum are thickened and can assume an elongated whorled pattern.

Culture of cloned cells from the mouse preputial gland tumor ESR 586.

Cells from the mouse preputial gland tumor ESR 586 have been cultured and cloned. Trypsin-ethylenediaminetetraacetate was used to obtain single cells. The cells are grown in a modified CMRL-1415 medium supplemented with 10% fetal calf serum. Clones tend to fall into two classes: Class 1, those that undergo morphological differentiation in liquid medium to form round bodies filled with lipid vaculoes; and Class 2, those that do not differentiate. Preliminary studies on the control of differentiation in Class 1 clones suggest that a minimum cell density is required before differentiation takes place. Analysis of the lipids from differentiating and nondifferentiating clones reveals the presence of sebaceous-type lipids in differentiating clones only. No requirement for testosterone was found for these cells.

Sebaceous gland differentiation: III. The uses and limitations of freshly isolated mouse preputial gland cells for the in vitro study of hormone and drug action.

The effects of selected hormones and drugs on freshly isolated mouse preputial gland cells have been studied. The steroid hormones, testosterone, DHT, androstanediol, androsterone and androstanedione all failed to stimulate, and estradiol failed to inhibit, either DNA or lipid synthesis under the conditions studied. Thyroxine and insulin had no effect on lipogenesis but epinephrine and PGE2 caused significant stimulation as did Bt2cAMP. The antilipemic drugs clofibrate, nicotinic acid and hydroxycitrate were all able to inhibit lipogenesis. Of the anti-acne drugs only L-DOPA was able to inhibit lipogenesis, neither tetracycline nor trans-retinoic acid showed any effect. Pyridoxine was unable to inhibit lipogenesis but DMSO caused dramatic stimulation though it was without effect on DNA synthesis. Evidence is presented which suggests that the lack of response to steroid hormones is not due to the inability of the cells to take up and metabolize the steroids but is due to the fact that the time-span of exposure is not long enough to elicit a cellular response. It is concluded that these freshly isolated cells are suitable for the study of those effects of hormones and drugs which occur within the first 3 hr after exposure to the compound.

Sebaceous gland differentiation: II. The isolation, separation and characterization of cells from the mouse preputial gland.

Viable cells have been isolated, by enzyme digestion, from mouse preputial glands and have been separated, by isopycnic centrifugation, into populations of different buoyant densities. The separated cells have been evaluated by morphological and biochemical criteria to assess the success of the separation procedure in terms of the stage of differentiation of each cell population. Use of Ficoll as gradient medium for the isopycnic centrifugation proved unsuccessful, but good separations were obtained when Metrizamide was used. The separated cells from the Metrizamide gradient were shown to be in different stages of differentiation. Techniques are described for the special handling of these cells as well as suitable assay procedures. Some of the properties of the separated cells are described.

Sebaceous gland differentiation. I. Separation, morphology and lipogenesis of isolated cells from the mouse preputial gland tumor.

Single cell suspensions have been prepared, by enzyme digestion, from the mouse preputial gland tumor and separated by flotation centrifugation into populations of different buoyant densities. These populations of cells have been shown by morphological, chemical and biochemical criteria to be in different stages of maturation. Some properties of the separated cells are described.

In-vitro testosterone metabolism in the mouse preputial gland: intercellular co-operation and changes with cell maturation.

In-vitro [14C]testosterone metabolism was investigated in isolated cells of adult male mouse preputial sebaceous glands. Labelled steroids were extracted and chromatographed after a 2-h incubation, and were identified as 5 alpha-dihydrotestosterone, androstenedione, 5 alpha-androstane-3,17-dione, 5 alpha-androstane-3 alpha,17 beta-diol and 5 alpha-androstane-3 beta,17 beta-diol, androsterone and 3-epiandrosterone. In cells separated according to state of maturity (lipid content) by isopycnic centrifugation in a metrizamide gradient, maximal testosterone metabolism occurred in large, nearly mature cells. In this population, mean hydroxysteroid 5 alpha-reductase and 17 beta-hydroxysteroid dehydrogenase activities were 3.8 and 2.3 nmol/10(6) cells per 2h respectively, more than 100-fold greater than in the densest population, comprised of undifferentiated and early differentiating cells. It was also found that the profile of testosterone metabolites was dependent on the proportion of the label metabolized. The metabolite index (MI), i.e. the average number of enzymatic steps undergone per molecule of metabolite, increased with increasing substrate utilization. Metrizamide showed reversible, non-specific inhibition of testosterone metabolism and reduction of the MI. Thus, it was postulated that testosterone is metabolized sequentially by different cells, with metrizamide inhibiting cellular uptake and intercellular substrate transport. This suggested that most of the metabolites would be found in the medium, rather than in the cellular compartment. Further, in incubations run without cell disaggregation, efficient substrate cycling among cells should result in a high MI, independent of metrizamide concentration and substrate utilization. These predictions were all confirmed, providing strong evidence that testosterone metabolism is a co-operative effort among several cells in this tissue.

Stability of an impulsively accelerated density interface in magnetohydrodynamics.

In the framework of ideal incompressible magnetohydrodynamics, we examine the stability of an impulsively accelerated, sinusoidally perturbed density interface in the presence of a magnetic field that is parallel to the acceleration. This is accomplished by analytically solving the linearized initial value problem, which is a model for the Richtmyer-Meshkov instability. We find that the initial growth rate of the interface is unaffected by the presence of a magnetic field, but for a finite magnetic field the interface amplitude asymptotes to a constant value. Thus the instability of the interface is suppressed. The interface behavior from the analytical solution is compared to the results of both linearized and nonlinear compressible numerical simulations.

The House of Lords Select Committee on the Assisted Dying for the Terminally III Bill: implications for specialist palliative care.

The Assisted Dying for the Terminally III Bill proposed to legalise both euthanasia and physician-assisted suicide for those with a terminal illness in the UK. A House of Lords Select Committee was convened to scrutinise this Bill and has recently published its report, which will be debated in Parliament on October 10th 2005. The written and oral evidence submitted to the Select Committee represented a wide range of views on 'assisted dying'. Much of the evidence from those countries which have legalised euthanasia/physician-assisted suicide (The Netherlands, Belgium, Switzerland and Oregon, USA) dealt with the practicalities of ending life, and the legal procedures and safeguards instigated in these countries. All the written and oral evidence in the public domain was scrutinised by the authors whilst the Select Committee was sitting. We have extracted those themes relevant to specialist palliative care practice and present them in this paper. We hope that this will provide a useful resource to inform the forthcoming public debate on assisted dying. The evidence of harms inherent in making such a change in the law, as presented to the Select Committee, has moved all three authors to oppose a change in the law.

Lipogenesis from amino acids in perfused isolated dog skin.

Lipogenesis from amino acids has been studied in isolated perfused dog skin. Uniformly labeled alanine-(14)C, glycine-(14)C, isoleucine-(14)C, leucine-(14)C, phenylalanine-(14)C, and valine-(14)C are all incorporated into the cutaneous lipids, with significant incorporation into most of the isolated lipid fractions. Efficiency of lipogenesis has been expressed relative to the extent of incorporation of acetate under the same experimental conditions. This efficiency was highest for the three branched-chain amino acids. The accuracy, uses, and limitations of the perfusion technique for the study of cutaneous lipogenesis have been evaluated.