ABSTRACTS 63
0.25% w/v A lakoocha solution as the test solution,
whereas the second and the third group, respectively,
received 0.25% licorice extract and 3% kojic acid as the
reference solutions in the same solvent. The subjects in
each group twice daily applied the test (or reference)
solution in one of her upper ann, whereas the remaining
arm was treated with only propylene glycol (self-control)
for 12 ffl:Cks. The melanin content of each application site
was measured using Mexameter every week and calculated
as %reduction in melanin content relative to the initial
melanin value (%whitening). The value of %whitening
was then compared between the product-treated and the
propylene glycol-treated arms within the same subject
using paired t-test (a ""0.05). The A lakoocha extract was
the most effective agent, giving the shortest onset of
significant whitening effect after only 4 weeks of
application (P 0.05), followed by 3% kojic acid (6 weeks)
and 0.25% licorice extract (10 weeks). The effect also
increased with time with maximum whitening observed at
week 12 for A. lakoocha extract. When the extract was
formulated as an oil-in-water emulsion, its whitening
efficacy was further enhanced. Daily application of 0.1%
w/w A lakoocha lotion to the upper arms (n =25) and
cheeks (n =15) of volunteers produced significant
whitening over the lotion base after 2 and 3 weeks,
respectively (P 0.05). Thus, the preliminary study
suggested that the heartwood extract of A lakoocha may
have a promising potential for use as an effective and
economical skin-whitening agent.
Heat Shock Proteins In The Skin
C. Jonak. G. Klosner and F. Trautinger
Heat shock proteins (hsp) are expressed in all cells and
organisms. Their expression is induced by heat shock
(temperatures above 42°C) and other forms of
pathophysiological stress. Elevated levels of hsp protect
cells from further stress exposure. Hsp are expressed
intracellularly. They are highly conserved throughout
evolution indicating hsp being necessary for survival under
potentially harmful environmental conditions. Hsp are
divided into families according to their molecular weight.
The majority of hsp function as molecular chaperones.
Chaperone function is characterized by binding to other
proteins and mediating their folding, transport and
interaction with other molecules. In human epidermis hsp
are abundantly expressed and have been linked with
functions in cell differentiation and photobiology. Recent
research has mainly focused on the 27 and 72 kD hsp that
are constitutively expressed in human keratinocytes.
ultraviolet radiation (UV)-induced cell death and sunburn
cell formation can be inhibited by previous heat shock
exposure and UV itself can induce hsp expression. The
expression of the 27 kD hsp (hsp27) in epidermal
keratinocytes in situ and in culture correlates with
differentiation. Expression of hsp27 increases
simultaneously with keratinocyte differentiation. For that
reason, hsp27 is described as a marker of epidermal
differentiation. Changes in the expression and inducibility
of hsp have been linked with ageing. In the skin, recent
data indicate that hsp72 expression remains remarkably
stable with intrinsic ageing. In contrast, levels of hsp27
have been found to be elevated in sun-protected aged skin
indicating a link between hsp27 expression and age-
dependent epidermal alterations. Regulation of hsp can be
modified by pharmacological intervention and the
development of safe topical and systemic treatments for the
prevention of skin damage and disorders of keratinocyte
differentiation can be expected for the future.
Histological Evaluation of Hyperpigmentation on Female
Filipino Axillary Skin
A G. James, J. E. Pople, W. E. Parish, A. E. Moore and N.
Dunbar
Females in South East Asia (Thailand, Indonesia and the
Philippines) show concern about dark areas of skin which
develop in their underarms, but little is known about the
features differentiating pale and hyperpigmented axillary
skin in the general population. To investigate this, a
histology study was undertaken in the Philippines to define
the aetiology of underarm darkening, which is postulated to
be a mild form of postinflammatory hyperpigmentation
(PIHP). Punch biopsies were taken from dark and light
axillary skin sites of 20 female subjects, of whom seven
had hyperpigmented underarms, based on an instrumental
(Mexameter MX-18, Courage and Kha?.aka Electronic
GmbH. Cologne, Germany) measure, and 13 had not.
Histological and immunohistochemical analyses were
undertaken using a range of stains and antibodies, including
haematoxylin-eosin for general histopa-thology, Masson-
Fontana for melanin, anti-CD68 for monocytes and
macrophages, Van Gieson's technique for fibrosis, anti-
proliferating cell nuclear antigen for cell mitosis, and the
melanocyte-specific immunostains, anti-tyrnsinase and
anti-tyrosinase-related protein 1. In most cases, dark skin
sites from hyperpigmented panellists had increased
intensity of Masson-Fontana, anti-tyrosinase and/or anti-
TRPl staining, indicative of melanocyte stimulation and
increased melanin production. Furthermore, hair plucking
emerged as a key stimulus to increased pigmentation. The
trauma of hair plucking slightly increased the number of
infiltrating mononuclear cells and macrophages that
ingested melanosomes leaking from the damaged
epidermis, more so in the skin of hyperpigmented
panellists this, in tum, potentially increases pigmentation.
However, cell infiltration was focal, mainly near the
plucked follicles, and not indicative of diffuse
inflammation. The results from this study support the
hypothesis that axillary darkening is mild PIHP,
characterized by increased epidermal melanin, following
stimulation or mild irritation of skin, with hair plucking as
a key factor in this process.
0.25% w/v A lakoocha solution as the test solution,
whereas the second and the third group, respectively,
received 0.25% licorice extract and 3% kojic acid as the
reference solutions in the same solvent. The subjects in
each group twice daily applied the test (or reference)
solution in one of her upper ann, whereas the remaining
arm was treated with only propylene glycol (self-control)
for 12 ffl:Cks. The melanin content of each application site
was measured using Mexameter every week and calculated
as %reduction in melanin content relative to the initial
melanin value (%whitening). The value of %whitening
was then compared between the product-treated and the
propylene glycol-treated arms within the same subject
using paired t-test (a ""0.05). The A lakoocha extract was
the most effective agent, giving the shortest onset of
significant whitening effect after only 4 weeks of
application (P 0.05), followed by 3% kojic acid (6 weeks)
and 0.25% licorice extract (10 weeks). The effect also
increased with time with maximum whitening observed at
week 12 for A. lakoocha extract. When the extract was
formulated as an oil-in-water emulsion, its whitening
efficacy was further enhanced. Daily application of 0.1%
w/w A lakoocha lotion to the upper arms (n =25) and
cheeks (n =15) of volunteers produced significant
whitening over the lotion base after 2 and 3 weeks,
respectively (P 0.05). Thus, the preliminary study
suggested that the heartwood extract of A lakoocha may
have a promising potential for use as an effective and
economical skin-whitening agent.
Heat Shock Proteins In The Skin
C. Jonak. G. Klosner and F. Trautinger
Heat shock proteins (hsp) are expressed in all cells and
organisms. Their expression is induced by heat shock
(temperatures above 42°C) and other forms of
pathophysiological stress. Elevated levels of hsp protect
cells from further stress exposure. Hsp are expressed
intracellularly. They are highly conserved throughout
evolution indicating hsp being necessary for survival under
potentially harmful environmental conditions. Hsp are
divided into families according to their molecular weight.
The majority of hsp function as molecular chaperones.
Chaperone function is characterized by binding to other
proteins and mediating their folding, transport and
interaction with other molecules. In human epidermis hsp
are abundantly expressed and have been linked with
functions in cell differentiation and photobiology. Recent
research has mainly focused on the 27 and 72 kD hsp that
are constitutively expressed in human keratinocytes.
ultraviolet radiation (UV)-induced cell death and sunburn
cell formation can be inhibited by previous heat shock
exposure and UV itself can induce hsp expression. The
expression of the 27 kD hsp (hsp27) in epidermal
keratinocytes in situ and in culture correlates with
differentiation. Expression of hsp27 increases
simultaneously with keratinocyte differentiation. For that
reason, hsp27 is described as a marker of epidermal
differentiation. Changes in the expression and inducibility
of hsp have been linked with ageing. In the skin, recent
data indicate that hsp72 expression remains remarkably
stable with intrinsic ageing. In contrast, levels of hsp27
have been found to be elevated in sun-protected aged skin
indicating a link between hsp27 expression and age-
dependent epidermal alterations. Regulation of hsp can be
modified by pharmacological intervention and the
development of safe topical and systemic treatments for the
prevention of skin damage and disorders of keratinocyte
differentiation can be expected for the future.
Histological Evaluation of Hyperpigmentation on Female
Filipino Axillary Skin
A G. James, J. E. Pople, W. E. Parish, A. E. Moore and N.
Dunbar
Females in South East Asia (Thailand, Indonesia and the
Philippines) show concern about dark areas of skin which
develop in their underarms, but little is known about the
features differentiating pale and hyperpigmented axillary
skin in the general population. To investigate this, a
histology study was undertaken in the Philippines to define
the aetiology of underarm darkening, which is postulated to
be a mild form of postinflammatory hyperpigmentation
(PIHP). Punch biopsies were taken from dark and light
axillary skin sites of 20 female subjects, of whom seven
had hyperpigmented underarms, based on an instrumental
(Mexameter MX-18, Courage and Kha?.aka Electronic
GmbH. Cologne, Germany) measure, and 13 had not.
Histological and immunohistochemical analyses were
undertaken using a range of stains and antibodies, including
haematoxylin-eosin for general histopa-thology, Masson-
Fontana for melanin, anti-CD68 for monocytes and
macrophages, Van Gieson's technique for fibrosis, anti-
proliferating cell nuclear antigen for cell mitosis, and the
melanocyte-specific immunostains, anti-tyrnsinase and
anti-tyrosinase-related protein 1. In most cases, dark skin
sites from hyperpigmented panellists had increased
intensity of Masson-Fontana, anti-tyrosinase and/or anti-
TRPl staining, indicative of melanocyte stimulation and
increased melanin production. Furthermore, hair plucking
emerged as a key stimulus to increased pigmentation. The
trauma of hair plucking slightly increased the number of
infiltrating mononuclear cells and macrophages that
ingested melanosomes leaking from the damaged
epidermis, more so in the skin of hyperpigmented
panellists this, in tum, potentially increases pigmentation.
However, cell infiltration was focal, mainly near the
plucked follicles, and not indicative of diffuse
inflammation. The results from this study support the
hypothesis that axillary darkening is mild PIHP,
characterized by increased epidermal melanin, following
stimulation or mild irritation of skin, with hair plucking as
a key factor in this process.
