Investigating Town Design and Social Organization at Port Tobacco, Maryland, Through the Use of Archaeology and Geophysics

This thesis examines the connection between town planning and social organization at the small town site of Port Tobacco in south-central Charles County, Maryland from the beginning of the 18th century through to the end of the 19th century. By employing a methodology of both geophysical techniques and archaeological excavations, I was able to locate and map numerous structures and features associated with town planning and examine how these spaces were used. This data was used to show how social order, power, and wealth transformed the town layout from a linear settlement along the river into a grid-like pattern. Specifically, I was able to show that these changes in town layout were dominated by the power of the local elite landowners and tobacco merchants

The Stromal Ultrastructure of Normal and Pathologic Human Corneas

This thesis describes results and observations from an ultrastructural study of the stroma of various human corneo-scleral tissues. The major components of the stromal extracellular matrix are collagen fibrils and proteoglycan macromolecules. Their character and distribution in normal human cornea and sclera are first studied. The main thrust of the research then progressed to elucidating the ultrastructure in two pathologic conditions where proteoglycan anomalies were known to occur; macular corneal dystrophy and corneal oedema. Transmission electron microscopical studies, employing the proteoglycan-specific stain Cuprolinic blue, demonstrated that the arrangement of proteoglycans, with respect to the collagen fibrils, in normal human cornea differs from other mammals in that there is more 'b' band association. Meridional X-ray diffraction showed that the axial electron density of human scleral collagen was similar to rat tail tendon collagen. When used in conjunction with Cupromeronic blue-staining, it verified as non-artifactual the electron microscopical observation that proteoglycans associate with collagen near the 'd/e' staining bands in the gap zone. Transmission electron microscopy revealed that macular dystrophy corneal stromas contain numerous collagen-free lacunae. Cuprolinic blue-staining further revealed that some of these lacunae contain congregations of various sized proteoglycan filaments. Enzyme digests identified these filaments as belonging to the chondroitin/ dermatan sulphate population of proteoglycans. It was concluded that aggregation of chondroitin/dermatan sulphate proteoglycans often occurs in the macular dystrophy stroma. X-ray diffraction data supported the electron microscopical observation of normal collagen fibrils in the macular dystrophy cornea. However, meridional X -ray data, from Cuprolinic blue-stained specimens, pointed to an abnormal distribution of proteoglycans along the collagen fibrils. Equatorial X-ray diffraction results indicated heterogeneous close packing of normal diameter collagen fibrils throughout the macular dystrophy stroma, this effect was deemed responsible for the central corneal thinning in vivo; a clinical feature of macular dystrophy. By using fresh tissue in the X-ray experiments, it was shown that that cryostorage of excised corneal buttons had no effect on the fibril dimensions. A collaboration was set up to analyse serum and corneal tissue immunochemically from the macular dystrophy patients, to characterise the type of macular dystrophy under investigation. There were no specific ultrastructural differences between type I and type II macular dystrophy stromas; an overall structural heterogeneity exists which indicates that the classification system is not, as yet, complete. High-angle X-ray patterns from macular dystrophy corneas contained two “extra reflections” not obtained from other human corneas, normal or pathologic. The reflections arise from 4.61Å and 9.62Å periodic structures which are considered to be glycosaminoglycan in origin. Electron microscopy revealed the presence of “wavy” lamellae and various sized collagen free “lakes” in the stroma of the oedematous hum an cornea, with the posterior portion containing by far the largest “lakes”. The existence of stromal “lakes” was further supported by the equatorial. X-ray diffraction data. Cuprolinic blue-stained transmission electron micrographs demonstrated a D-periodic association of proteoglycans with collagen, which suggested a depletion of keratan sulphate in the oedematous stroma; this was backed-up by immunochemical evidence. Large proteoglycan filaments (possibly chondroitin/dermatan sulphate) were observed in some parts of the extracellular matrix. Scheie’s syndrome corneal stromas, which contain no α-L-iduronidase, also contained dense Cuprolinic blue-stained deposits. The possibility exists that aggregation of corneal chondroitin/dermatan sulphate is a common factor of several corneal pathologies

Chronic Scleroedema

Two patients with chronic scleroedema are presented. One patient had severe joint contractures. The literature on scleroedema is reviewed and the relationship of scleroedema to the stiff skin syndrome is discussed.S. Afr. Med. J., 48, 164, (1974)

Axial electron density of human scleral collagen. Location of proteoglycans by x-ray diffraction

The low angle meridional x-ray diffraction pattern from fresh human sclera was analyzed to ascertain if collagen-bound proteoglycans affect the axially-projected electron density distribution to the same extent as appears to occur in the cornea. The results showed that, unlike cornea, the electron density of the sclera is similar to that seen in rat tail tendon collagen. The proteoglycans were specifically stained using either Cuprolinic blue or Cupromeronic blue, both under critical electrolyte conditions. The tissue was then examined by electron microscopy and by low angle x-ray diffraction. The electron-optical observations suggested that proteoglycans associate with collagen near the d/e staining bands in the gap zone. A difference Fourier analysis from the x-ray results confirmed that these observations were not e.m. preparative artefacts and allowed a quantitative estimate to be made of the axial extent of the proteglycans in the wet tissue

Generation of a TALEN-mediated, p63 knock-in in human induced pluripotent stem cells

The expression of p63 in surface ectodermal cells during development of the cornea, skin, oral mucosa and olfactory placodes is integral to the process of cellular self-renewal and the maintenance of the epithelial stem cell status. Here, we used TALEN technology to generate a p63 knock-in (KI) human induced pluripotent stem (hiPS) cell line in which p63 expression can be visualized via enhanced green fluorescent protein (EGFP) expression. The KI-hiPS cells maintained pluripotency and expressed the stem cell marker gene, ΔNp63α. They were also able to successfully differentiate into functional corneal epithelial cells as assessed by p63 expression in reconstructed corneal epithelium. This approach enables the tracing of p63-expressing cell lineages throughout epithelial development, and represents a promising application in the field of stem cell research

Topical delivery of a Rho-kinase inhibitor to the cornea via mucoadhesive film

The application of inhibitors of the Rho kinase pathway (ROCK inhibitors) to the surface of the eye in the form of eyedrops has beneficial effects which aid the recovery of diseased or injured endothelial cells that line the inner surface of the cornea. The aim of this study was to test the plausibility of delivering a selective ROCK inhibitor, Y-27,632, to the cornea using a thin polymeric film. Mucoadhesive polymeric thin films were prepared incorporating Y-27,632 and diffusional release into PBS was determined. Topical ocular delivery from the applied film was investigated using freshly excised porcine eyes and eyedrops of equivalent concentration acted as comparators; after 24 h the formulations were removed and the corneas extracted. Drug-loaded thin polymeric films, with high clarity and pliability were produced. ROCK inhibitor Y-27,632 was weakly retained within the film, with release attaining equilibrium after 1 h. This in turn facilitated its rapid ocular delivery, and an approximately three-fold greater penetration of Y-27,632 into cryoprobe-treated corneas was observed from the thin film (p < 0.01) compared to eyedrop. These findings support the further development of ROCK inhibitor delivery to the cornea via release from thin mucoadhesive films to treat vision loss cause by corneal endothelial dysfunction

Ocular surface ectoderm instigated by WNT inhibition and BMP4

We sought to elucidate how and when the ocular surface ectoderm commits to its differentiation into the corneal epithelium in eye development from human induced pluripotent stem cells (hiPSCs) under the influence of WNT signaling and the actions of BMP4. These signals are key drivers ocular surface ectodermal cell fate determination. It was discovered that secreted frizzled related protein-2 (SFRP2) and Dickkopf1 (DKK1), which are expressed in neural ectoderm, are both influential in the differentiation of hiPSCs, where they act as canonical WNT antagonists. BMP4, moreover, was found to simultaneously initiate non-neural ectodermal differentiation into a corneal epithelial lineage. Combined treatment of hiPSCs with exogenous BMP4 aligned to WNT inhibition for the initial four days of differentiation increased the ocular surface ectodermal cell population and induced a corneal epithelial phenotype. Specification of a surface ectodermal lineage and its fate is thus determined by a fine balance of BMP4 exposure and WNT inhibition in the very earliest stages of human eye development

Protecting the Upper Chesapeake Bay: Fort Hollingsworth (1813-1815), Elk River, Cecil County, Maryland

Fort Hollingsworth, erected in April 1813 by the citizens of Cecil County, Maryland, was a small breastwork that protected the upper reaches of the Chesapeake Bay and the “backdoor” to Philadelphia during the War of 1812. Fort Hollingsworth saw brief action in 1814. After the war, it was demolished and the land returned to farming. Geophysical surveying, exploratory soil borings, detailed topographic mapping, and focused excavation conducted by the Archeological Society of Maryland convincingly and economically identified the footprint of Fort Hollingsworth. Methodological considerations are here coupled with a discussion of vernacular fortifications and the implications that unconventional fortifications have for their archaeological discovery and recordation

Microwave treatment of the cornea leads to localised disruption of the extracellular matrix

Microwave keratoplasty is a thermo-refractive surgical procedure that can correct myopia (short-sightedness) and pathologic corneal steepening by using microwave energy to cause localised shrinkage around an annulus of the cornea leading to its flattening and vision correction. The effects on the corneal extracellular matrix, however, have not yet been evaluated, thus the current study to assess post-procedure ultrastructural changes in an in-vivo rabbit model. To achieve this a series of small-angle x-ray scattering (SAXS) experiments were carried out across whole transects of treated and untreated rabbit corneas at 0.25 mm intervals, which indicated no significant change in collagen intra-fibrillar parameters (i.e. collagen fibril diameter or axial D-period), whereas inter-fibrillar measures (i.e. fibril spacing and the degree of spatial order) were markedly altered in microwave-treated regions of the cornea. These structural matrix alterations in microwave-treated corneas have predicted implications for corneal biomechanical strength and tissue transparency, and, we contend, potentially render microwave-treated corneas resistant to surgical stabilization using corneal cross-linking procedures currently employed to combat refractive error caused by corneal steepening

A multicentre trial of voltaren in the treatment of rheumatoid arthritis

Voltaren, a compound with analgesic, anti-inflammatory and antipyretic properties, has been compared at two dose levels-25 mg t.d.s. and 50 mg t.d.s. with indomethacin 25 mg t.d.s. and acetylsalicylic acid 1 500 mg t.d.s. Ninety-one patients with definite or classical rheumatoid arthritis took part in this study. The trial was a doubleblind cross-over study, with each  medication being given for one week. Patients were washed out for one week prior to the first active treatment. Each patient received only two of the four possible treatments. Voltaren in a dose of 25 mg t.d.s. was found to improve the symptoms of rheumatoid arthritis to a greater degree than indomethacin or acetylsalicylic acid. Voltaren 50 mg t.d.s. evoked a greater response than acetylsalicylic acid and was at least as efficacious as indomethacin. Voltaren was better tolerated than either indomethacin or acetylsalicylic acid. The incidence of gastro-intestinal side-effects was similar with Voltaren and indomethacin, and half that produced by acetylsalicylic acid. Some evidence of possible drug interaction was found.S. Afr. Med. J., 48, 2013 (1974)