Influence of prior activity on residual limb volume and shape measured using plaster casting: results from individuals with transtibial limb loss.

The purpose of this research was to determine whether prior activity affected the shape of a plaster cast taken of a transtibial residual limb. Plaster casts were taken twice on one day in 24 participants with transtibial limb loss, with 5 s between doffing and casting in one trial (PDI-5s) and 20 min in the other trial (PDI-20m). The ordering of the trials was randomized.

A Novel Measurement Device for Volume Management in Lower Limb Amputees: A Technical Note.

Many amputees suffer from irritation and wounds as a result of poor residual limb volume management. Reasons contributing to failure to maintain volume properly include peripheral neuropathy, cognitive impairment, and social/cultural issues. Amputees commonly use socks of various thicknesses to account for diurnal limb volume loss.

Recent translational research: computational studies of breast cancer.

The combination of mathematics--queen of sciences--and the general utility of computers has been used to make important inroads into insight-providing breast cancer research and clinical aids. These developments are in two broad areas. First, they provide useful prognostic guidelines for individual patients based on historic evidence.

The effects of chemotherapeutics on cellular metabolism and consequent immune recognition.

Awidely held view is that oncolytic agents induce death of tumor cells directly. In this report we review and discuss the apoptosis-inducing effects of chemotherapeutics, the effects of chemotherapeutics on metabolic function, and the consequent effects of metabolic function on immune recognition. Finally, we propose that effective chemotherapeutic and/or apoptosis-inducing agents, at concentrations that can be achieved physiologically, do not kill tumor cells directly.

Lamellar granule biogenesis: a role for ceramide glucosyltransferase, lysosomal enzyme transport, and the Golgi.

Although lamellar granules are critical to the formation of the epidermal permeability barrier and are a known marker of late keratinocyte differentiation, very little is known about the physiologic regulators of lamellar granule assembly and extrusion. Ceramide glucosyltransferase (CGT), the enzyme responsible for the synthesis of lamellar granule glucosylceramides (GlcCer; the precursors of the stratum corneum ceramides), is localized to the Golgi apparatus in other cell types. We have found that CGT is induced during keratinocyte culture differentiation coincident with increased GlcCer content and the appearance of lamellar granules.

In vitro reconstitution of stratum corneum lipid lamellae.

In the final stages of differentiation in the epidermis of terrestrial mammals, lipids are extruded into the intercellular spaces. The initially extruded lipid becomes transformed into broad, multilamellar sheets that are found in the intercellular spaces throughout the stratum corneum. These lamellae display an unusual alternating broad-narrow-broad pattern of lucent bands as revealed by transmission electron microscopy (TEM).

Proposal for a new model of breast cancer metastatic development.

Background: The commonly accepted theory of breast cancer metastatic development assumes continuous tumor growth from tumor seeding until documentation of clinical recurrence. In particular, Gompertzian growth kinetics is currently the theoretical cornerstone of the natural history of breast cancer, and has been widely utilized for planning treatments.

Materials And Methods: To verify agreement between findings and the implications of the continuous growth model, several published papers about the natural history of breast cancer after removal of the primary tumor were reviewed.

Computer simulation of a breast cancer metastasis model.

Recent analysis of relapse data from 1173 untreated early stage breast cancer patients with 16-20 year follow-up shows that frequency of relapse has a double peaked distribution. There is a sharp peak at 18 months, a nadir at 50 months and a broad peak at 60 months. Patients with larger tumors more frequently relapse in the first peak while those with smaller tumors relapse equally in both peaks.

Lipids of hamster cheek pouch epithelium.

The hamster cheek pouch is a much used but incompletely understood experimental model. In particular, the cheek pouch epithelial lipids, which are important for permeability barrier function as well as other aspects of epithelial biology, have not been completely characterized. In the present study, the complete lipid class composition has been determined by thin-layer chromatography in conjunction with photodensitometry.

Development of an optimal protocol for the ultrastructural examination of skin by transmission electron microscopy.

The intercellular lipid bilayers of the stratum corneum provide the permeability barrier of the skin. To perform an electron microscopical examination of the ultrastructure of these bilayers, ruthenium tetroxide fixation is required. In this study an optimal fixation protocol was developed and selected upon comparing seven different fixation procedures, using glutaraldehyde (GA) and the postfixatives ruthenium red, osmium tetroxide (OsO4) and ruthenium tetroxide (RuO4) in combination with potassium ferrocyanide (K4Fe(CN)6) and potassium ferricyanide (K3Fe(CN)6).

Regional variation in content, composition and organization of porcine epithelial barrier lipids revealed by thin-layer chromatography and transmission electron microscopy.

Epidermis and oral epithelia provide permeability barriers that limit penetration of potentially harmful agents. Barrier function is determined by lipids in the superficial epithelial layers and varies regionally by more than 10-fold. The purpose of this study was to determine whether differences in lipid content, composition or organization could account for this variation in barrier function.

Osmium tetroxide and ruthenium tetroxide are complementary reagents for the preparation of epidermal samples for transmission electron microscopy.

Ruthenium tetroxide and osmium tetroxide were compared as post-fixatives in the preparation of human epidermis for transmission electron microscopic examination. Both reagents revealed characteristic lamellar granules within the granular layer and extruded lamellar granule contents in the upper granular layer. The transformation of the granule contents into multilamellar sheets at the interface between the granular and cornified layers and the persistence of these sheets through all levels of the stratum corneum were demonstrated only with ruthenium tetroxide fixation.

Organization of the intercellular spaces of porcine epidermal and palatal stratum corneum: a quantitative study employing ruthenium tetroxide.

Previous studies have demonstrated that the intercellular spaces of the stratum corneum contain multilamellar lipid sheets with variable ultrastructure in addition to desmosomes or desmosomal remnants. The intercellular lamellae are thought to provide a permeability barrier whereas the desmosomes are responsible for cell-cell cohesion. In this study, transmission electron microscopy of RuO4-fixed tissue was used to compare the proportions of the intercellular spaces in epidermal and palatal stratum corneum occupied by desmosomes and by different patterns of lamellae.

Gaming: a creative strategy for staff education.

Providing staff development in a stimulating, innovative manner is the challenge of all nurse educators. This article discusses gaming, a creative teaching strategy that can help meet these needs. Games designed specifically for the education of dialysis staff will be reviewed.

Computer model challenges breast cancer treatment strategy.

The breast cancer treatment failure rate remains unacceptably high. The current breast cancer treatment paradigm, based primarily on Gompertzian kinetics and animal models, advocates short-course, intensive chemotherapy subsequent to tumor debulking, citing drug resistance and host toxicity as the primary reasons for treatment failure. To better understand treatment failure, we have studied breast cancer from the perspective of computer modeling.

An alternative approach for treatment of breast cancer.

Since adjuvant chemotherapy and hormonal therapy generally extend disease free survival in breast cancer rather than provide a cure, we have examined the current breast cancer paradigm. Heterogeneity is a fundamental characteristic of breast cancer tissue and a well recognized aspect of the disease. There are variations in natural history, histopathology, biochemistry and endocrinology, and molecular biology of cancer tissues and cells within the tissues.

Covalently bound lipids in keratinizing epithelia.

Covalently bound lipids have been identified and compared in keratinizing porcine epithelia including epidermis and oral epithelium from palate and gingiva. Stratum corneum was isolated by tryptic digestion, and after extensive extraction of lipids using a series of chloroform-methanol mixtures, the residual tissue was subjected to alkaline hydrolysis to release covalently bound lipids. The lipids so released were analyzed by quantitative thin-layer chromatography.

The possible relationship between mercury from dental amalgam and diseases. I: Effects within the oral cavity.

Mercury is released from dental amalgams, and therefore it is necessary to consider the biological and clinical consequences of such exposure. Intraorally, it would appear as though mercury can cause hypersensitivity/toxic reactions resulting in lichen planus lesions, and may play a major role in the pathogenesis of gingivitis, periodontitis and periodontal disease.

Studies of epidermal lipids using electron microscopy.

Ruthenium tetroxide fixation has permitted the electron microscopic visualization of intercellular lipid lamellae in thin sections of stratum corneum. This development complements prior freeze-fracture studies of lipid lamellae and has advanced our knowledge about the ultrastructure of epidermal lipids in several ways. We have demonstrated a continuous lipid envelope that surrounds each differentiated stratum corneum cell and the presence of lipid lamellae throughout the entire stratum corneum of three mammalian species, including humans.

Characterization of bone cells isolated on discontinuous Percoll gradients: distribution in sequentially derived populations.

Bone cell populations obtained by sequential digestion of newborn mouse calvariae remain morphologically heterogeneous despite well-documented biochemical differences. Fractionation of these populations on Percoll gradient reveal three major cell groups of low, intermediate, and high buoyant density (1.056, 1.

Surgical complications of continuous ambulatory peritoneal dialysis.

Surgical experience with 260 consecutive patients with chronic renal failure receiving continuous ambulatory peritoneal dialysis (CAPD) at one medical center from 1980 to 1989 is reviewed. Patients received CAPD for a mean of 24.2 months (range: 3 days to 91 months).

Sphingolipid metabolism in organotypic mouse keratinocyte cultures.

Ceramides are the dominant component of the stratum corneum intercellular lipid lamellae, which constitute the epidermal permeability barrier. Only pig and human epidermal ceramides have been extensively characterized and the structures of the ceramides of cultured keratinocytes have not been previously investigated. In the present studies, we have characterized the ceramides synthesized by organotypic lifted mouse keratinocyte cultures for the first time and compared them to the ceramides of intact mouse epidermis.

Is Gompertzian or exponential kinetics a valid description of individual human cancer growth?

It is generally accepted that human cancers grow in an exponential or Gompertzian manner. This assumption is based on analysis of the growth of transplantable animal tumors and on averages of tumor growth in human populations. A computer model of breast cancer in individual patients has raised some doubts about this assumption.