A new cyclic thioanhydride derived from chlorophyll a and its aurophilic properties

Article abstract of DOI:10.1016/j.dyepig.2020.108858

The need to modify the chlorine macrocycle by additional exocycles is dictated by the desire to increase the stability of the pigment, improve its spectral characteristics, including the shift of the main absorption band to the long-wavelength region, as well as the introduction of chemically active groups for the introduction of other bioactive molecules. Replacing the oxygen atom in the purpurin-18 anhydride exocycle with a sulfur atom can be considered as a bioisosteric substitution, which should not strongly affect the spectral and biological properties of the photosensitizer, but may allow the implementation of new chemical modifications at the periphery of the macrocycle. In this paper, we propose a synthesis pathway for a derivative of naturally occurring chlorin that contains an additional thioanhydride cycle attached to the main macrocycle. We report the spectral characteristics of the compound and demonstrate the possibility of immobilization of chlorin p₆ thioanhydride on gold nanoparticles (Au-NP).

Full text of DOI:10.1016/j.dyepig.2020.108858

Arab Journal of Urology (2016) 14, 216–222
Arab Journal of Urology
Official Journal of the Arab Association of Urology)
(
www.sciencedirect.com
STONES/ENDOUROLOGY
ORIGINAL ARTICLE
Implications of different nephrolithometry scoring
systems on clinical practice of endourologists: An
international web-based survey
a,
a
Mohamed A. Elkoushy , Adel H. Metwally , Yasser A. Noureldin
b
*
a
Department of Urology, Suez Canal University, Ismailia, Egypt
Department of Urology, Benha University, Benha, Egypt
b
Received 29 February 2016, Received in revised form 13 April 2016, Accepted 29 April 2016
Available online 10 June 2016
KEYWORDS
Abstract Objectives: To assess the implications of different nephrolithometry scor-
ing systems (NLSS) on clinical practice of endourologists to predict stone-free status
Endourology;
Percutaneous
nephrolithotomy;
Outcome;
Nomogram;
Clinical practice pat-
tern
(
SFS) after percutaneous nephrolithotomy (PCNL).
Methods: A web-based survey was sent to members of the Endourological
Society. Demographic and practice pattern data were collected. Multiple-choice
and open-ended questions were used to assess awareness about the NLSS and their
authentic use in clinical practice. Surgeon preferences and limitations of NLSS and
how to overcome them were asked.
Results: In all, there were 162 responses, including 17 (10.5%) respondents who
were not aware of NLSS. Most respondents (82.1%) denied the efficacy of NLSS
in predicting SFS after PCNL. Of 145 respondents who were aware of NLSS,
85.5% did not use them in clinical practice. Endourologists aged 40–60 years
(P < 0.001), in practice for 10–20 years (P = 0.003), those performing 100–200
PCNLs/year (P = 0.02), and those from North America (P < 0.001) seemed to
use NLSS more frequently. In all, 50% of respondents preferred not to use any
NLSS, while 29% chose the S.T.O.N.E followed by the Guy’s Stone Score
(10.3%) and The Clinical Research Office of the Endourology Society (CROES)
nomogram (8.3%). Inconsistency and variability among different NLSS were the
main drawbacks reported by 82% of 89 respondents. The need for high-level
evidence for NLSS through direct randomised prospective comparison was
recommended by 24.8% of respondents who answered that question.
ABBREVIATIONS
CROES, the Clinical
Research Office of the
Endourology Society;
NCCT, non-contrast
CT;
NLSS, nephrolithome-
try scoring systems;
PCNL, percutaneous
nephrolithotomy;
SFS, stone-free status;
*
Corresponding author at: Suez Canal University, Ismailia, Egypt. Tel.: +20 010 001 35102.
E-mail addresses: mohamed_elkoushy@med.suez.edu.eg, melkoushy@yahoo.com (M.A. Elkoushy).
Peer review under responsibility of Arab Association of Urology.
Production and hosting by Elsevier
http://dx.doi.org/10.1016/j.aju.2016.04.005
2
090-598X Ó 2016 Arab Association of Urology. Production and hosting by Elsevier B.V.
This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Incorporation of Nephrolithometry Scoring Systems in Clinical Practice
217
S-ReSC, Seoul
Conclusion: There is a lack of compliance and acceptance of different NLSS in
clinical practice among endourologists. Inconsistency and inaccuracy in predicting
SFS after PCNL limits their incorporation into clinical practice. However, the
results of this study might not be generalisable due to the selection bias resulting
from the geographical distribution of the respondents and the heterogeneity in sur-
gical expertise. Therefore, randomised prospective direct comparisons and valida-
tion of these systems are recommended.
National University
Renal Stone Complex-
ity;
S.T.O.N.E., Stone
Size, Tract length,
Obstruction/hydrone-
phrosis, Number of
involved calyces,
Essence/Hounsfield
units
Ó 2016 Arab Association of Urology. Production and hosting by Elsevier B.V. This
is an open access article under the CC BY-NC-ND license (http://creativecommons.
org/licenses/by-nc-nd/4.0/).
Introduction
NLSS in achieving their objectives. The question now
is whether the validation of different NLSS have been
Percutaneous nephrolithotomy (PCNL) has become the
standard procedure for large renal stones in most recent
guidelines [1]. In the past decade, PCNL has been per-
formed increasingly in the USA, a trend which is
assumed to continue [2]. However, inconsistent defini-
tions and accepted standardised reporting of PCNL out-
comes may impact the quality of urological research and
influence any comparative evaluation for the manage-
ment of urolithiasis between different series [3,4].
Moreover, preoperative patient counselling necessitates
the development of an integrated scoring system to
assess PCNL complexity for optimal decision-making
translated into a change in the practice patterns among
practitioners. In other words, are practising endourolo-
gists convinced of the utility of these NLSS and their
ability to predict post-PCNL outcomes? The present
worldwide survey was planned and conducted as a trial
to answer this question and to assess the implications of
NLSS on
endourologists.
clinical
practice
patterns
among
Methods
An internet-based survey was sent to the members of the
Endourology Society using their e-mail addresses. The
website remained open for 2 months (9 September to 9
November 2015) to give the respondents an opportunity
to visit and complete the online survey. The survey was
sent by e-mail independently and was planned to be con-
cise enough to obtain the answers to the research ques-
tions. On 9 October 2015, friendly reminder e-mails were
re-sent to encourage those who missed the first invita-
tion to complete the survey. The survey was set to
receive only one response per computer to avoid the
potential response bias of duplicate responses, especially
when sending such reminders.
Demographic and practice pattern data were col-
lected, including age, place and years of practice, and
the number of PCNLs performed within the previous
12 months. In addition, multiple-choice and open-
ended questions were used to assess awareness of the
endourologists about the current NLSS, authentic use
in clinical practice, surgeon preferences, and reliability
of these systems in accurately predicting SFS after
PCNL. Also, the respondents were queried about the
limitations of the NLSS, reasons for not using them,
and how to overcome such obstacles (Appendix 1). Par-
ticipants were given the option to check more than one
option for question number 7.
[
3].
Therefore, different scoring systems and nomograms
have been introduced to overcome these limitations for
systematic and quantitative assessment of the outcomes
of PCNL including the Guy’s Stone Score [5], S.T.O.N.
E. (Stone Size, Tract length, Obstruction/hydronephro-
sis, Number of involved calyces, Essence/Hounsfield
units) nephrolithometry scoring system [6], The Clinical
Research Office of the Endourology Society (CROES)
nomogram [7], and the Seoul National University Renal
Stone Complexity (S-ReSC) score [8,9]. All these
nephrolithometry scoring systems (NLSS) aim for pre-
operative prediction of stone-free status (SFS) and com-
plications through assessment of the complexity of
different cases undergoing PCNL. NLSS do not only
consider the imaging criteria of stones and renal anat-
omy, but also relevant patient characteristics such as
body mass index, previous renal surgery, and surgeon
experience.
However, these NLSS were validated only in retro-
spective studies [10–15] and they all have their own lim-
itations. In addition, these systems seem to suffer from
an intrinsic bias favouring predictive efficacy that is
dependent on the evaluated population of patients
[
11]. Furthermore, SFS may also be affected by surgeon
experience, heterogeneity of practice, surgical modifica-
tions among different centres, and involvement of post-
graduate trainees, which should be considered as well.
Currently, there are no sufficient high-level evidence
data regarding the applicability and reliability of these
NLSS
The Guy’s Stone Score, S.T.O.N.E. nephrolithometry
score and CROES nomogram consist of 11 variables,

2
18
Elkoushy et al.
including four shared parameters (stone size, location,
number, and staghorn status). Other variables which
are considered by these three NLSS are stone density,
renal anatomy, tract length, obstruction of renal pelvis,
case load/year, prior treatment history, and the presence
of spina bifida or spinal injury.
The Guy’s Stone score categorises PCNL cases into
four grades, increasing in complexity from Grade 1 to
Grade 4, depending on patients’ past medical history
and non-contrast CT (NCCT) [5]. The S.T.O.N.E.
nephrolithometry scoring system assesses PCNL com-
plexity by nine different possible scores, ranging from
wide range of PCNL caseloads with only 12.3% of
respondents performing a high volume of cases.
In all, 17 respondents (10.5%) were not aware of
NLSS and were excluded from data analysis of ques-
tions numbers 6–10, bringing the total number of
respondents to these questions to 145 (89.5%) respon-
dents. The 10.5% of respondents who were not aware
of NLSS came from Africa and Asia (5.6% and 4.9%,
respectively). Most of them (9.2%) were aged <40 years
and had practised for <10 years (8.6%), while their
PCNL case load was zero or <100 procedures in the
previous 12 months (6.2% and 4.3%, respectively).
Surprisingly, most respondents (82.1%) denied the
efficacy of NLSS in accurately predicting SFS after
PCNL, including 33.8% who were not sure (Fig. 1). This
was translated into 124 of 145 respondents (85.5%) who
did not use NLSS in their daily clinical practice.
Respondents who did not use NLSS are characterised
in Fig. 2, including 66% of those aged 40–60 years
vs > 91% in the other two age groups (P < 0.001),
64.4% of those in practice for 10–20 years vs 82–90%
in the other two groups (P = 0.003), 65.5% in those
performing 100–200 PCNLs vs 70–100% in the other
two groups (P = 0.02), and 54.9% in North America
vs 74.1–93.8% for the other continents (P < 0.001).
When asking about the explanation of the latter
response, the responses were obtained from only 72
(58.1%) of those who did not use NLSS. The responses
obtained were: 80.5% of respondents reported that
some of these NLSS are time-consuming, while others
found that NLSS did not consider some factors that
could impact postoperative outcomes such as surgeon
5
to 13, according to five NCCT-calculated parameters
including stone size, tract length, obstruction/
hydronephrosis, number of involved calyces, essence/
Hounsfield units [6].
However, the CROES nephrolithometric nomogram
predicts treatment success using plain X-ray of the kid-
neys, ureters and bladder considering the stone burden,
count, and location, in addition to case volume and
prior stone treatment [7]. The total score to predict the
chance of treatment success is the sum of individual
scores derived from each predicting variable; the higher
the score, the higher the chance of treatment success,
while a patient with a low score has a low chance of
achieving a SFS [7].
On the other hand, the S-ReSC score is calculated by
counting the number of sites involved in the renal pelvis
and calyces, regardless of stone parameters or renal
anatomy. This system assigns a score from 1 to 9
depending mainly on the number of sites involved; the
renal pelvis (1), superior and inferior major calyces
(2–3), anterior and posterior minor calyces of the supe-
rior (4–5), middle (6–7), and inferior calyces (8–9).
Table 1 Baseline and demographic characteristics of the
respondents.
Statistical analysis
Variable
N (%)
Data were analysed using the commercially available
Statistical Package for Social Science (SPSS) for win-
dows, version 20 (Chicago, IL, USA). Descriptive data
were presented in terms of number of responses,
percentages, medians and interquartile range (IQR).
Fisher’s exact test was used for comparing discrete vari-
ables with a two-tailed P < 0.05 indicating significant
differences between groups.
Respondents
Age, years
162 (100)
<
40
0–60
60
42 (25.9)
97 (59.9)
23 (14.2)
4
>
Place of practice
Africa
Asia
32 (19.7)
25 (15.4)
9 (5.6)
Australia
Europe
27 (16.7)
51 (31.5)
18 (11.1)
North America
South America
Results
Duration of practice, years
<10
A total of 162 responses were obtained within the
2
50 (30.9)
73 (45.1)
39 (24.1)
1
0–20
20
-month period from September to November 2015.
>
Most of the responses came from North America, Africa,
and Europe (31.5%, 19.7%, and 16.7%, respectively).
Most endourologists were aged 40–60 years (59.9%)
and had practised for 10–20 years (45.1%) (Table 1).
Over the previous 12-months, the respondents performed
a median (IQR) of 152 (63–182) PCNLs. There was a
Number of PCNL performed within the previous 12 months
None
100
00–200
200
8 (4.9)
<
76 (46.9)
58 (35.8)
20 (12.3)
1
>

Incorporation of Nephrolithometry Scoring Systems in Clinical Practice
219
Figure 3 Which NLSS do you use or prefer to use?
Figure
1
Implications of NLSS on clinical practice of
respondents.
Discussion
Several NLSS have been developed in the past few years
to predict the outcomes of PCNL. However, these NLSS
lack high-level evidence to show their reliability and
reproducibility, despite both the Guy’s Stone Score
and S.T.O.N.E nephrolithometry score having been
tested for inter-observer concordance, albeit retrospec-
tively. Therefore, these NLSS are limited by the data
captured, as they are unable to take into account factors
that may influence the outcome of PCNL such as sur-
geons’ experience and skills, together with the emerging
techniques that would improve the SFS such as retro-
grade intrarenal surgery combined with PCNL.
In the current era of NLSS, there are no data avail-
able about their implementation in clinical practice
and whether practising endourologists are convinced
of their utility and ability to predict the outcomes of
PCNL. The present study was conducted to address this
issue and to assess the implications of these NLSS on
clinical practice patterns among endourologists.
In the present survey, 10% of the respondents were not
aware of NLSS, while 85.5% of the remaining respon-
dents do not use them in their daily clinical practice. This
could be explained by the finding that most respondents
(82.1%) denied the efficacy of NLSS to accurately predict
post-PCNL SFS. Moreover, 80% of those who do not use
NLSS found them time-consuming, inconsistent and/or
inaccurate. A lack of level-1 evidence to support their
use in clinical practice, increased workload, and complex-
ity of these systems may also explain the high percentage
of those who do not use them.
Characterisation of respondents who use/do not use
NLSS in clinical practice showed that middle-aged
respondents (aged 40–60 years), those in practice for
10–20 years, and those performing 100–200 PCNLs in
the previous 12-months used NLSS significantly more
than either extreme. It seems also that respondents from
North America use NLSS significantly more frequently
than their colleagues from other continents.
Figure 2 Characterisation of respondents who did not use NLSS
in clinical practice.
experience. Increased work load was reported by 18.1%,
in addition to 12.5% who cited the complexity of these
systems and lack of their clinical utility for not using
NLSS.
When questioned about which NLSS is currently or is
preferred to be used, 50.3% of respondents chose no
one, while 29% choose the S.T.O.N.E nephrolithometry
score followed by the Guy’s Stone Score and CROES
nomogram (10.3% and 8.3%, respectively; Fig. 3). Only
three respondents (2.1%) recommended the S-ReSC and
all of them came from Asia.
In all, 89 (61.4%) respondents provided several draw-
backs or obstacles to using NLSS in clinical practice.
Inconsistency and variability among different systems
were reported by 82% of the respondents. When ques-
tioned whether they had any recommendations to over-
come these limitations and/or improve the validity of
NLSS, only 36 (24.8%) participants responded to that
question and most of them recommended the need for
high-level evidence for these NLSS through direct
prospective comparison between these systems in a ran-
domised controlled trial. Others mandated a large mul-
ticentre series to ensure matched or similar groups of
patients.
While half of the respondents would not like to use
NLSS in clinical practice, 29% favoured the S.T.O.N.
E, followed by the Guy’s Stone Score and CROES

2
20
Elkoushy et al.
nomogram. Those who preferred to use the S.T.O.N.E
nephrolithometry score found it easier and more practi-
cal than the other scoring systems. Despite the Guy’s
Stone score, S.T.O.N.E. nephrolithometry score and
CROES nomogram being equally predictive of post-
PCNL SFS in one study, Labadie et al. [11] considered
that the S.T.O.N.E. nephrolithometry scoring system
provides more accurate data stratification than the
Guy’s Stone score and offers an easier application than
the CROES nomogram. Despite a scale incorporation
into the latter nomogram to help practitioners to give
a percentage chance of treatment success, it was found
by some respondents to be the most difficult to apply
in clinical practice. Furthermore, a multicentre study
including 850 patients found that the S.T.O.N.E.
nephrolithometry score accurately predicted surgical
outcomes after PCNL, including SFS and overall com-
plications [16]. However, these results should be cau-
tiously interpreted as participation of different
institutions with different raters in such a retrospective
approach would impact its outcomes. Conversely, the
S-ReSC was recommended by only three Asian respon-
dents, despite appearing to be much easier. However, it
does not account for the stone characteristics specifically
the stone size, which remains the leading predictor of
perioperative outcome in all the published reports.
In the present study, inconsistency and variability
among different NLSS were reported to be the main
problems of using them in clinical practice. Post-
PCNL complications may be considered as a good
example of such variability where some authors found
significant positive association between the Guy’s Stone
scoring system and post-PCNL complications [17,18],
while others did not detect a similar correlation [5,14].
However, it is unfortunate that the respondents did
not make a distinction between the different NLSS, as
it seems obvious that all NLSS were not considered to
be equally time consuming, complex, and/or inaccurate,
from the respondents’ point of view.
independently to the e-mail addresses of the endourolo-
gists, which may be potentially outdated. A response
bias may be expected by respondents who may have
been more inclined to complete the survey due to their
interest in the subject. Moreover, the unequal worldwide
distribution of the respondents may represent a domi-
nate practice from a certain continent such as North
America. This has been indicated and deserves to be
highlighted. Furthermore, lack of data about academic
versus community practice of the respondents might
limit interpretation of some findings. Unequal distribu-
tion of respondents over different continents might also
limit the generalisability of the present results. Neverthe-
less, the present survey appears to reveal a disparity
between research and real clinical settings, highlighting
the necessity for high-level evidence rather than retro-
spective trials when trying to validate a new technique
or evaluation tools.
Conclusion
There is a lack of compliance and acceptance of differ-
ent NLSS among endourologists in clinical practice.
Endourologists aged 40–60 years, in practice for
10–20 years, those performing 100–200 PCNLs/year,
and those from North America seem to use NLSS
significantly more frequently than their colleagues.
Inconsistency and inaccuracy of some NLSS to predict
post-PCNL outcomes limits their incorporation into clin-
ical practice. However, the results of the present study
might not be generalisable due to the selection bias result-
ing from the geographical distribution of the respondents
and the heterogeneity in surgical expertise. Therefore,
randomised controlled trials are recommended for direct
comparison and validation of these NLSS.
Compliance with ethical standards
All procedures performed in studies involving human
participants were in accordance with the ethical stan-
dards of the institutional and/or national research com-
mittee and with the 1964 Helsinki declaration and its
later amendments.
This article is an online survey and does not contain
any studies with human participants or animals per-
formed by any of the authors.
When questioned about their advice to overcome
these limitations and to improve the validity of NLSS,
most respondents recommended direct prospective com-
parison between these NLSS in randomised controlled
trials. A large multicentre series is awaited to ensure
matched or similar groups of patients. Others recom-
mended a single, reliable, and reproducible NLSS, which
is adequately comprehensive for thorough reporting and
comparison. This would help to answer the current
question regarding how clinicians incorporate research
advances into clinical practice as such trials with a rising
tide of consensus invariably lead to practice changes to
deliver optimum care to the patients. Nevertheless,
incorporation of research advances into practice will
typically require more time and more proof.
Author’s contributions
Mohamed A. Elkoushy:
Project development
Data collection and management
Data analysis
Manuscript writing and editing
Adel H. Metwally:
Data collection and management
Being a web-based survey, the present study may be
limited by the low response rate, despite it being sent

Incorporation of Nephrolithometry Scoring Systems in Clinical Practice
221
Manuscript writing and editing
Yasser A. Noureldin:
Data management
Source of funding
None.
Manuscript writing and editing
Appendix 1: Online questionnaire
Conflicts of interest
All the authors declare no conflicts of interest.

2
22
Elkoushy et al.
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