Bioprospecting keratinous materials

The concept of bioprospecting for bioactive peptides from keratin-containing materials such as wool, hair, skin and feathers presents an exciting opportunity for discovery of novel functional food ingredients and nutraceuticals, while value-adding to cheap and plentiful natural sources. The published literature reports multiple examples of proline-rich peptides with productive bio-activity in models of human disease including tumour formation, hypertension control and Alzheimer’s disease. Bioactive peptides have been identified from food and other protein sources however the bioactivity of keratin-related proteins and peptides is largely unknown. Considering the high representation of proline-rich peptides among proven bioactive peptides, the proline-rich character of keratinous proteins supports current research. A selection of mammalian (cow epidermis, sheep wool) and avian (chicken feather) keratinous materials were subjected to enzymatic hydrolysis using established processing methods. A bio-assay of determining inhibition of early stage amyloid aggregation involved using a model fibril-forming protein – reduced and carboxymethylated bovine K-casein (RCMk-CN) and quantitation of fibril development with the amyloid-specific fluorophore, Thioflavin T (ThT). The assay was fully validated for analytical repeatability and used together with appropriate positive controls. Peptide library products derived from chicken feather (n=9), sheep wool (n=9) and bovine epidermis (n=9) were screened in the fibril inhibition assay based on K-casein. 3 of 27 products exhibited interesting levels of bio-activity with regard to fibril inhibition. HPLC profiles provide an indication of the complexity of the assemblage of peptides in the three active products. We conclude the bioprospecting research using keratinous materials shows promise for discovery of useful bioactive peptides.

Location of Keratin-associated Proteins in Developing Fiber Cuticle Cells using Immunoelectron Microscopy

AIMS

To investigate the location of keratin-associated proteins (KAPs) in developing hair fiber cuticle cells using transmission electron microscopy with immunogold techniques and specific antibodies. Other studies were aimed at detecting the presence of cornified envelope proteins including involucrin and loricrin. MATEIALS AND METHODS: Polyclonal antibodies were produced in rabbits against peptides from KAPS 5.1, KAPS 10.1 ultra high-sulfur proteins.

RESULTS

The KAP proteins were found to form part of the developing exocuticle and a- layer. Cornified envelope proteins (involucrin and loricrin) were absent consistent with recent findings.

CONCLUSIONS

The results have been discussed in terms of a revised model for fiber cuticle surface barriers including their role in fiber cuticle surface function.

Management of primary cicatricial alopecias: options for treatment

Primary cicatricial alopecias (PCAs) are a poorly understood group of disorders that result in permanent hair loss. Clinically, they are characterized not only by permanent loss of hair shafts but also of visible follicular ostia along with other visible changes in skin surface morphology, while their histopathological hallmark usually (although not always) is the replacement of follicular structures with scar-like fibrous tissue. As hair follicle neogenesis in adult human scalp skin is not yet a readily available treatment option for patients with cicatricial alopecias, the aim of treatment, currently, remains to reduce symptoms and to slow or stop PCA progression, namely the scarring process. Early treatment is the key to minimizing the extent of permanent alopecia. However, inconsistent terminology, poorly defined clinical end-points and a lack of good quality clinical trials have long made management of these conditions very challenging. As one important step towards improving the management of this under-investigated and under-serviced group of dermatoses, the current review presents evidence-based guidance for treatment, with identification of the strength of evidence, and a brief overview of clinical features of each condition. Wherever only insufficient evidence-based advice on PCA management can be given at present, this is indicated so as to highlight important gaps in our clinical knowledge that call for concerted efforts to close these in the near future.

Loose anagen syndrome as a severity factor for trichotillomania

Loose anagen syndrome (LAS) is a condition of childhood where anagen hairs are easily and painlessly extracted. The condition is due to poor adhesion between the cuticle of the hair shaft and the inner root sheath. A 4-year-old girl presented with patches of hair loss and a clinical diagnosis of trichotillomania was made. A hair pull test extracted multiple hairs easily and painlessly. Light microscopic examination was consistent with LAS. A biopsy was performed, which showed features of trichotillomania. However, on request the child did not display sufficient dexterity to pull out her own hair. It was subsequently determined that her hair loss was likely to be due to a third person plucking out her hair. It appears that in this case the LAS was not the cause of her hair loss, but rather acted as a severity factor for trichotillomania by proxy in that the lack of pain on plucking the hairs removed the principle deterrent.

Disappearance of pili annulati following an episode of alopecia areata

Pili annulati is a distinctive autosomal dominant hair shaft disorder that produces alternating light and dark bands that can give a spangled appearance to the hair. The literature contains three case reports of patients in whom the condition has disappeared following recovery from alopecia totalis. None of these reports contain a direct microscopic comparison of pre- and post-regrowth hairs. We report a 6-year-old girl who was first noted to have pili annulati at the age of 2 years and who developed alopecia totalis at the age of 3 years. When the hair regrew spontaneously, 18 months later, the pili annulati was no longer visible. Hair samples obtained before and after the episode of alopecia areata were compared by normal and cross-polarized light microscopy. While not apparent on careful clinical examination, banding was present on light microscopy in 20% of the hairs. Eighty per cent of the affected hairs displayed banding throughout their entire length. In contrast, prior to the episode of alopecia totalis, when the pili annulati was clearly visible, 50% of the hair obtained was banded on microscopy and 90% of the affected hairs showed banding throughout their microscopic length.

Keratosis pilaris and hereditary koilonychia without monilethrix

Keratosis pilaris is found commonly in isolation as well as associated with other conditions. We describe a family with keratosis pilaris and hereditary koilonychia, with an autosomal dominant pattern of inheritance. These two findings have only been previously found in the context of monilethrix. The coexistence of the two disorders suggests a close association of their genetic pathogenesis.

Spironolactone-induced hepatitis

There is widespread use of spironolactone in medical practice and the indications for its use well established and side effect profile well known. Herein, we present a case of drug-induced hepatitis occurring in a 50-year-old woman using spironolactone for the treatment of androgenetic alopecia. Six weeks after commencement of spironolactone the patient became unwell, complained of an extensive itch, but no icterus or jaundice. Liver function tests found abnormally elevated bilirubin and enzymes levels. After withdrawal of spironolactone, the patient's symptoms resolved and liver function improved. To date, there has only been one other report of spironolactone-induced hepatitis.

Management of male pattern hair loss

The management of androgenetic alopecia (AGA) has been materially altered by the availability of the 5 alpha-reductase type 2 inhibitor, finasteride. Nevertheless, this agent is only one component of successful management, and an understanding of the role of camouflage agents, surgical options, and other medical treatments is important. Because no treatment completely reverses baldness, it is important to communicate the limitations of each modality to the patient so that he has appropriate expectations of the outcome of any intervention. Patient counseling and support are also often relevant.

Perceptions of acne vulgaris in final year medical student written examination answers

Misconceptions exist in the community regarding factors that exacerbate acne vulgaris. In particular stress, diet, lifestyle and personal hygiene are often erroneously claimed to be important factors. In order to investigate whether these common misconceptions persist in medical graduates, we analysed the answers of 215 sixth year medical students, who all subsequently graduated from The University of Melbourne, to a short-answer question on acne management and exacerbating factors in one of their final year examination papers. With respect to exacerbating factors, 67% of students identified stress, 10% identified lifestyle factors (smoking and alcohol consumption), and 25% claimed poor facial hygiene exacerbated acne. Diet was stated to be an important factor by 41% of students, of whom 12% specifically mentioned chocolate. Persistence of these misconceptions among medical graduates is likely to perpetuate misinformation in the community.

Nail apparatus melanoma

Nail apparatus melanoma is a relatively rare variant of melanoma with a disproportionately high mortality when compared with melanoma elsewhere. The aetiology and natural history remain poorly understood. There is no clear epidemiological association with race, skin type or sun exposure. Universally accepted clinical and histological criteria for the diagnosis of early nail apparatus melanoma have not been defined. The two cardinal clinical signs are melanonychia striata and Hutchinson's sign. These are useful but not pathognomonic of melanoma. Diagnostic delay is frequent and patients commonly have advanced disease at the time of diagnosis. Surgical excision is advocated for treatment of stage I disease; however, the most appropriate re-excision margins, including the level of amputation where required, have not been determined. Early diagnosis and excision of the tumour is the only treatment known to increase survival. Adjuvant systemic chemotherapy, isolated limb perfusion, and routine elective lymph node dissection have been used, but no survival benefit has been demonstrated.

Genetics of alopecia areata

Alopecia areata is a common disorder with a genetic predisposition where interaction with environmental factors leads to episodes of terminal hair loss. In this review article, we examine the evidence for a genetic basis to this disorder and discuss the prospects for future research into genetic susceptibility areas and the problems that are likely to be encountered in such research.

Permanent alopecia following chemotherapy and bone marrow transplantation

Alopecia can be a psychologically daunting prospect for people requiring cancer chemotherapy. Fortunately, most patients experience only temporary hair loss. We report the case of a 23-year-old woman with chronic myeloid leukaemia who developed permanent, near-total alopecia of her scalp, eyebrows, eyelashes, axillary and public hair following busulphan and cyclophosphamide chemotherapy which was used as conditioning prior to allogeneic bone marrow transplantation. The histology from a scalp biopsy revealed hair follicle destruction. Topical minoxidil failed to induce significant re-growth.

Cryosurgery of benign skin lesions

Cryosurgery is a widely used treatment modality in dermatology. Its place in cutaneous malignant and premalignant disease is well established; however, it also has great utility with benign lesions. Vascular, infectious, fibrotic diseases, solar damage, acne, as well as some cosmetic defects are amenable to freezing. The mechanism of treatment involves inducing tissue damage, vascular stasis and occlusion, as well as inflammation, to destroy unwanted tissue. After destruction of epidermal lesions, healing involves rapid re-epithelialization over a relatively cold-insensitive dermal network. Side effects are common but shortlived and are rarely severe. The equipment required is relatively economical and readily available. The technique is straightforward and reproducible, making cryosurgery an attractive option for many commonly encountered benign skin conditions. This review outlines treatment with the timed spot freeze technique of some commonly encountered benign lesions.

Understanding and managing common baldness

BACKGROUND

Society places importance on physical attributes especially the appearance of our hair. Common baldness or androgenetic alopecia is a normal physiological process of hair loss in genetically predisposed individuals. Premature or accelerated hair loss can engender considerable negative thoughts and anxiety associated with feelings of diminished attractiveness.

OBJECTIVE

To enable general practitioners to recognise the various treatment options available, therefore offering patients reasonable hope and informed choices.

DISCUSSION

Common baldness can be prevented by currently available mediums and regrowth may be achieved in a significant percentage of cases. Correct use of these agents requires an understanding of the pathogenesis of androgenetic alopecia, its natural history and the time course of response to treatment.

Cryosurgery of malignant and premalignant diseases of the skin: a simple approach

Cryosurgical treatment of skin cancer and premalignant conditions of the skin has been in widespread use for 20 years. Data accumulated over this period suggest that if attention is paid to the treatment technique and to lesion selection, then cure rates equivalent to radiotherapy, simple surgical excision, and curettage and cautery can be achieved reliably. Moh's micrographic surgery offers a higher cure rate for skin cancer, but is not suitable for the vast majority of lesions seen in clinical practice. The decision to use cryosurgery to treat any particular lesion will therefore be influenced by a number of other considerations. Cryosurgery competes well on morbidity and cosmetic outcome and is the quickest, easiest, cheapest and most readily available of the treatment options. As such it has earned its place among the recognized treatment modalities for skin cancers as well as premalignant conditions of the skin. Cryosurgery is commonly delivered empirically without record of the dose delivered and without audit of the outcome. The aim of this review is to describe in detail one standard technique of therapy that is easily reproduced and has been audited; the timed spot freeze technique. This technique can be used, even by those inexperienced in cryosurgery, to achieve predictable success rates. Many other techniques do exist, but either have not been audited or are unnecessarily cumbersome.

The basement membrane zone of the nail

The anatomy of the epidermis, dermis and subcutaneous tissues of the nail apparatus is distinct from that of non-appendageal skin. Apart from the demonstration of the longitudinal configuration of the dermal-epidermal junction of the nail bed, there have been no studies of the composition of the basement membrane zone of the nail apparatus. We obtained three human accessory digits, including one thumb, all of which had been amputated for cosmetic reasons, and were without known pathology. Specimens were stained with a battery of monoclonal and polyclonal antibodies which target normal basement membrane zone antigens, and studied by indirect immunofluorescence. This study demonstrated that the four distinct regions of the nail, namely the proximal nail fold, the nail matrix, the nail bed and the hyponychium expressed all the target antigens found in the normal non-appendageal basement membrane. In particular, there was normal expression of the epidermal-associated antigens, the 220- and 180-kDa bullous pemphigoid antigens, and the alpha 6 beta 4 integrin. There was also normal expression of the lamina lucida antigens LH39, GB3 and laminin. It is of interest that the dermal-associated components, namely the 285-kDa linear IgA antigen, the extracellular matrix glycoproteins chondroitin sulphate, type VII collagen and its closely associated proteins, and the poorly characterized antigen for LH24 and LH39 were all normally expressed. Fibronectin, which is not a normal basement membrane zone component, was diffusely expressed in the extracellular matrix, but did not accentuate the basement membrane zone.(ABSTRACT TRUNCATED AT 250 WORDS)

Proteolytic enzymes in wound healing: the role of enzymatic debridement

Proteolytic enzymes are a family of proteins that serve to degrade necrotic debris derived from cell breakdown. They are produced endogenously often as precursor proteins whose activation is precisely regulated. These activated enzymes serve many functions in normal as well as pathological situations. In particular they are involved in the regulation of cell maturation and multiplication; collagen synthesis and turnover; the development and removal of the perivascular fibrin cuffs found in venous insufficiency and leg ulceration as well as the removal of dead tissues following inflammation. As a limited number of enzymes perform all these functions, it is difficult to predict the effects of applying synthetic proteolytic enzymes to a wound. Many such enzymes are currently commercially available and being promoted as alternatives to surgical wound debridement. It is important for their use to be considered in the context of their interaction with endogenous proteases, their physiological role in tissue, their ability to reach a desired target and the stage of wound healing at the time they are applied.

Congenital inclusion dermoid cysts of the scalp

The natural history of congenital inclusion dermoid cysts of the scalp is unknown. We report three cases of this condition, which has been followed from birth for up to ten years. Dermoids are congenital subcutaneous cysts, which gradually flatten and scar over a number of years. The lesions are covered with skin showing focal alopecia but they may be surrounded by a collar of hypertropic hair. Later in life flattened cysts may be mistaken for aplasia cutis, but the history of a cyst at birth allows the clinician to distinguish these two conditions. As these cysts have a potential for intracranial extension, this is an important clinical entity.

Chemical and nonchemical components of ventilation during hypercapnic exercise in man

Nine young athletes performed treadmill exercise at average VO2 levels of 1.08, 1.78, 3.00, and 3.57 l/min while exposed to inspired PCO2 levels of 0, 10, 20, 30, and 40 Torr. The average slope of the VE-PACO2 relationship increased significantly from 3.59 to 4.70 l.min-1.Torr-1 in the transition from rest to light exercise and then decreased progressively and significantly to 1.34 l.min-1.Torr-1 at the highest work load. A similar pattern of initial increased steepness followed by progressive flattening was found in the VT-PACO2, curves, whereas slopes of the f-PACO2 relationships continuously decreased in the transition from rest through light to heavy exercise. These data are consistent both with an increased ventilatory response to PACO2--[H+]a increments during light exercise and with progressive reduction of that response during the transition from light to heavy exercise in parallel with increasingly severe mechanical influences on VE as maximal limits are approached. They are not consistent with simple addition of chemical and nonchemical components of exercise hyperpnea at all levels of exercise.