Effect of Cutaneous Hypoxia upon Erythema and Pigment Responses to UVA, UVB, and PUVA (8-MOP + UVA) in Human Skin**Persented in part at the Annual Meeting of The Society for Investigative Dermatology, Inc., Washington, D.C., May 7–9, 1984 (J Invest Dermatol 82:420, 1984).

The effect of oxygen deprivation upon UVA-, UVB-, and PUVA- induced pigment and erythema responses in normal human skin was examined. Before exposure, varying degrees of hypoxia in the skin of the forearm were achieved by inflating sphygmomanometer cuff applied to the upper arm. After the transcutaneously measured pO2 had stabilized, sites on the inner forearm were exposed to UVA, UVB, or 8-MOP + UVA radiation, to determine dose thresholds for the induction of erythema and pigmentation at different cuff pressures. Inflation of the cuff to greater than systolic pressure completely inhibited immediate and delayed pigment responses (IPD, DT) to UVA doses greater than 10 times the normal pigmentation threshold dose. UVA-induced delayed erythema responses were partially inhibited by cuff inflation: 2.7 times the minimal erythema dose of UVA was necessary to cause an erythema response when exposure occurred during vascular occlusion. In contrast, erythema and pigments responses to UVB and PUVA were unaltered by cuff pressures exceeding systolic pressure during exposure. Inhibition of UVA-induced erythema and pigment responses by vascular occlusion were reversed by the transcutaneous diffusion of 100% O2. These findings indicate that the cutaneous responses to UVA and UVB occur by separate pathways differing with respect to O2-dependence. Our findings agree with those of other studies which indicate that PUVA-induced phototoxicity and melanogenesis are not O2-dependent

Cyclic Tetrapyrrolic Photosensitisers from the leaves of Phaeanthus ophthalmicus

<p>Abstract</p> <p>Background</p> <p>Twenty-seven extracts from 26 plants were identified as photo-cytotoxic in the course of our bioassay guided screening program for photosensitisers from 128 extracts prepared from 64 terrestrial plants in two different collection sites in Malaysia - Royal Belum Forest Reserve in the State of Perak and Gunung Nuang in the State of Selangor. One of the photo-cytotoxic extracts from the leaves of <it>Phaeanthus ophtalmicus </it>was further investigated.</p> <p>Results</p> <p>The ethanolic extract of the leaves from <it>Phaeanthus ophtalmicus </it>was able to reduce the <it>in vitro </it>viability of leukaemic HL60 cells to < 50% when exposed to 9.6 J/cm²of a broad spectrum light at a concentration of 20 μg/mL. Dereplication of the photo-cytotoxic fractions from <it>P. ophthalmicus </it>extracts based on TLC R_fvalues and HPLC co-injection of reference tetrapyrrolic compounds enabled quick identification of known photosensitisers, pheophorbide-<it>a</it>, pheophorbide-<it>a </it>methyl ester, 13²-hydroxypheophorbide-<it>a </it>methyl ester, pheophytin-<it>a </it>and 15¹-hydroxypurpurin 7-lactone dimethyl ester. In addition, compound <b>1 </b>which was not previously isolated as a natural product was also identified as 7-formyl-15¹-hydroxypurpurin-7-lactone methyl ester using standard spectroscopic techniques.</p> <p>Conclusions</p> <p>Our results suggest that the main photosensitisers in plants are based on the cyclic tetrapyrrole structure and photosensitisers with other structures, if present, are present in very minor amounts or are not as active as those with the cyclic tetrapyrrole structure.</p

Coronary artery calcification – distribution, extent and 1-year outcomes in patients with low to intermediate pre-test probability of coronary artery disease.

Background: Coronary artery calcium (CAC) is an established marker to predict major cardiovascular events (MACE), and has incremental value over traditional risk factors (CVRF). CAC is widely available, easily reproducible, and used in nearly all coronary computed tomography angiography (CCTA) assessment protocols for coronary artery disease (CAD). The distribution and extent of CAC, and its prognostic implications in local Malaysian patients with low to intermediate pre-test probability (LI-PTP) of CAD had not been established. Objectives: We aimed to establish the distribution, extent and prognostic implications of CAC in patients without known CAD, but with LI-PTP of CAD, undergoing CCTA for chest pain evaluation. Methods: Clinical information was obtained from consecutive patients who underwent CAC and CCTA examination from January 2020 to January 2021 at a single public access tertiary referral centre. The primary outcomes were the distribution and extent of CAC, and its relationship with MACE at 1 year. Results: Of 499 consecutive patients, 7 were excluded due to high PTP. CAC was present in 172/492 (35%). Within this group, 74/172 (41.3%) had CAC score of 1-100 (mild), 75/172 (42.4%) had a CAC of 101- 400 (moderate), 23/172 (13.4%) had CAC of >400 (high). 136 had suspected significant CAD and was offered conventional coronary angiography (CCA). 91/492 underwent CCA, and 38 were found to have significant CAD. Of those found to have significant CAD, 7/38 (18.4%) had CAC of zero, 8/38 (21.1%) had mild CAC, 12/38 (31.6%) moderate, and 11/38 (30%) high CAC. Severe CAC was associated with a higher rate of revascularization 11/23 (47.8%), compared to those with zero 7/320 (2.2%), mild 8/74 (10.8%) and moderate 12/75 (16%) CAC. Predictors of high CAC were age, male gender, and presence of cardiovascular disease risk factors. Of the 492 patients, 230 patients completed 1 year follow-up, and from this, 1 patient had a MACE. Conclusion In patients with LI-PTP risk of CAD, CAC was seen in approximately one third of our cohort. In the group with high CAC, a higher proportion required coronary revascularization, but MACE remained low at 1 year

Prevalence of Acid alpha-Glucosidase (GAA) Pseudodefiency Allele and It’s Clinical Significance Among Patients with Cardiomyopathy

Background: Pompe disease is an autosomal recessive lysosomal storage disorder caused by deficiency of lysosomal acid alpha-glucosidase (GAA) activity, leading to the progressive accumulation of glycogen in lysosomes of the skeletal and cardiac muscles. An alpha-glucosidase (GAA) pseudodeficiency allele is a change in the GAA gene sequence that results in GAA enzyme activity reduction, but does not cause Pompe disease. In Japan and Taiwan, there is high prevalence of pseudodeficiency allele (c.1725G>A and c.2065G>A) detected from their newborn screening. We observed similar prevalence of pseudodeficiency allele among our patients who had genetic test performed for suspected hereditary cardiomyopathy. Objectives: To report the prevalence of GAA pseudodeficiency allele, and to ascertain its clinical significance among patients with cardiomyopathy. Methods: The clinical data of the patients with GAA mutations were retrieved. Patients were called back for neurological examination, lung function test, measurement of creatine kinase (CK) level and dried-blood-spot for GAA enzymatic activity. Results: From January to December 2021, 33 patients underwent genetic testing. 23 out of the 33 genetic analyses included GAA mutation. 9 (39.13%) out of 23 were tested positive for pseudodeficiency allele. Their median age was 53 years (range 29-82), 44.4% were males with equal ethnic distribution (33.3% Malay, 33.3% Chinese, 33.3% Dayaks). All were heterozygous for the pseudodeficiency allele: 5 (55.6%) with c.[1726A; 2065A] allele, the other 4 (44.4%) c.2065G>A. The underlying cardiomyopathy phenotypes were hypertrophic (44.4%), transthyretin amyloid (22.2%), hypertensive (22.2%) and Fabry (11.1%). 1 patient (11.1%) with transthyretin amyloid cardiomyopathy died of advanced heart failure at age 79 years. 1 patient had mild motor weakness of the limbs attributable to thyrotoxicosis, while the other 7 patients had normal skeletal motor function. Their median predicted forced vital capacity was 87.5% (range 76-103), median CK level was 103 U/L (range 39-297) and median GAA activity was 4.8 micromol/l/h (range 3.2-9.2) [normal > 2.0]. Conclusion: The prevalence of GAA pseudodeficiency allele among patients with cardiomyopathy is 39.13%. None of the patients exhibit significant muscle weakness or respiratory insufficiency despite low normal enzymatic activity. Whether the presence of pseudodeficiency allele affects the prognosis of the underlying cardiomyopathy remains uncertain

Coronary Computed Tomography Angiography as part of initial strategy, in assessment of patients with chest pain – clinical experience and 1 year prognosis.

Background: Coronary computed tomography angiography (CCTA) has been showed to have high specificity and sensitivity for detecting coronary artery disease (CAD). In Malaysia, national guidelines state that CCTA may be used in low- to intermediate pre-test probability (LI-PTP) of CAD, who have an equivocal functional test result, and who are asymptomatic or mildly symptomatic with good exercise capacity. Recent evidence suggested a ‘CCTA-first’ strategy in the evaluation of a patient with chest pain could provide prognostic benefits. Prognostic benefits of adopting this strategy in Malaysia has not been well studied. Objectives: We aimed to evaluate 12-month clinical outcomes of patients with LI-PTP, using the CCTA as an initial strategy, or as part of the work-up for, chest pain assessment. Methods: Consecutive patients who underwent CCTA examination from January 2020 to January 2021 were enrolled. Clinical information was then extracted. Primary outcome was defined as presence of stenosis of >50% in a major epicardial coronary artery; and secondary outcome defined as a composite of all-cause mortality, non-fatal myocardial infarction (MI) and coronary revascularisation. Results: Among the initial 499 patients, 7 were excluded as they were high in PTP. The mean PTP was 47.1±26.3. Baseline characteristics were available in 300 patients. The mean age was 53.5±11.4 years, 59.3% were male, 18.6% were diabetic, 71.2% had hypertension, and 50.8% had hypercholestrolaemia. 1.9% had an equivocal functional test for ischaemia. Of the 492 LI-PTP patients who underwent CCTA, 136 patients were suspected to have significant CAD, and recommended conventional coronary angiography (CCA). Of these, 91 patients underwent CCA. From this group 38 were found to have significant CAD which warranted revascularisation – 32 by percutaneous coronary intervention (PCI) and 6 referred for coronary artery bypass surgery (CABG). Therefore, utilising this strategy, 7.7% (38/492) of patients met the primary outcome. Of the original cohort of 492 LI-PTP patients, only 230 completed 1 year follow up, and from this, one patient met the secondary outcome. Conclusion Incorporation of CCTA into contemporary chest pain evaluation identified significant number of patients with significant CAD and was also associated with a low cardiac event rate at 1 year follow-up

Impact of Myocardial Viability Assessed by Delayed Enhancement Cardiovascular Magnetic Resonance on Clinical Outcomes in Real World Practice

Background: Delayed enhancement cardiovascular magnetic resonance imaging (DeCMRI) has become the preferred method for viability assessment. It is well established that viable dysfunctional myocardium has the potential for functional recovery after revascularization. Objective: Our objective is to evaluate whether viability assessment by DeCMRI affects clinical outcome in daily clinical practice. Methodology:We retrospectively studied 132 consecutive patients (114 male, mean age 59 ± 10 years) with ischaemic cardiomyopathy (Mean LVEF: 29.1 ± 14%) who underwent CMRI viability testing from 1st Jan-31st Dec 2015 in our centre. Patientswere divided into 3 groups: Group A: Viable myocardium- optimal medical therapy only (38.6%); B: Viable myocardium- revascularization done (29.5%); and C: Nonviable myocardium (29.5%). Results: Mean age for groups A, B and C were 61.2, 58.3, 56.2 years respectively, p=0.048. The proportion of triple vessel disease in each of the groups were 56.1%, 54.5% and 38.5% (p=0.44); whereas left main involvement was 31.7%, 21.2% and 19.2% respectively (p=0.43). Majority of group C patients did not undergo revascularisation (90%). Group B had statistically significant EF improvement (5.5%, SD 11.9) compared to Group A (-0.6%, SD 6.7) and Group C (-1.2%, SD 9.8), p value 0.014. Mortality at 1 year was significantly higher in Group A compared to Group Band C (31.4%, 7.7% and 12.8% respectively, p=0.009). MACE rates were also increased in Group A compared to the other two groups (41.2%, 20.5% and 27.0%, p=0.09). Odds Ratio for MACE was 3.01 (95% Cl 1.22 - 7.45) for Group A vs B and 2.8 (95% Cl 1.1 - 6.9) for Group A vs C. Conclusion: Patients with viable myocardium who did not undergo revascularization (group A) had the worst prognosis, even when compared to those with non-viable myocardium; with significantly higher 1-year mortality. Although not statistically significant, there was also a trend towards higher MACE in these patients. These findings emphasize that patients with poor LV function but viable myocardium need to undergo revascularisation and that optimal medical therapy alone is not sufficient

Utility of Dutch Lipid Clinic Network Score to Estimate Prevalence of Familial Hypercholestrolemia in Patients with ST-Elevation Myocardial Infarction

Background Hypercholesterolaemia is prevalent in the Malaysian population, and its treatment control rates remain suboptimal1. Familial hypercholesterolemia (FH) is an autosomal dominant condition that leads to accelerated arteriosclerotic cardiovascular disease (ASCVD). The prevalence of FH in the general population worldwide has been postulated to be 1:3132 and 1:100 in the Malaysian community3. It has been proposed that lipid lowering treatment prevents further increase in total cardiovascular risk of FH patients, and this recommendation is extensible for FH patients plus atherosclerotic CAD (coronary artery disease). However, despite its implication in CAD, FH is still an underdiagnosed and undertreated condition2-4. To date, the prevalence of FH in the STEMI (ST-elevation myocardial infarction) population in Malaysia is not studied. Establishing the prevalence of FH among patients with CAD and comparing this with the general population would help future efforts at identifying subjects with FH. Objective We aim to estimate the prevalence of FH in patients with STEMI in Sarawak using Dutch Lipid Clinic Network (DLCN) score. Materials and Methods Patients who were admitted for type-1 STEMI from April 2021 until July 2021 to Pusat Jantung Sarawak were recruited. History taking and physical examination were carried out on-site. FH was screened clinically using DLCN score. Results Out of the recruited patients, 45% of the cohort was clinically categorized into probable/ possible FH without genetic testing. Mean age and low density lipoprotein (LDL) were 52.7 and 3.38mmol/l respectively. Prevalence of premature CAD was 63%. Male gender, smoking, high BMI was the most frequent risk factor observed. Conclusions Prevalence of probable/possible familial hypercholesterolemia in a STEMI cohort using DLCN score is 45%. DLCN score in the STEMI cohort is not related to LDL levels

Dynamically-Driven Inactivation of the Catalytic Machinery of the SARS 3C-Like Protease by the N214A Mutation on the Extra Domain

Despite utilizing the same chymotrypsin fold to host the catalytic machinery, coronavirus 3C-like proteases (3CLpro) noticeably differ from picornavirus 3C proteases in acquiring an extra helical domain in evolution. Previously, the extra domain was demonstrated to regulate the catalysis of the SARS-CoV 3CLpro by controlling its dimerization. Here, we studied N214A, another mutant with only a doubled dissociation constant but significantly abolished activity. Unexpectedly, N214A still adopts the dimeric structure almost identical to that of the wild-type (WT) enzyme. Thus, we conducted 30-ns molecular dynamics (MD) simulations for N214A, WT, and R298A which we previously characterized to be a monomer with the collapsed catalytic machinery. Remarkably, three proteases display distinctive dynamical behaviors. While in WT, the catalytic machinery stably retains in the activated state; in R298A it remains largely collapsed in the inactivated state, thus implying that two states are not only structurally very distinguishable but also dynamically well separated. Surprisingly, in N214A the catalytic dyad becomes dynamically unstable and many residues constituting the catalytic machinery jump to sample the conformations highly resembling those of R298A. Therefore, the N214A mutation appears to trigger the dramatic change of the enzyme dynamics in the context of the dimeric form which ultimately inactivates the catalytic machinery. The present MD simulations represent the longest reported so far for the SARS-CoV 3CLpro, unveiling that its catalysis is critically dependent on the dynamics, which can be amazingly modulated by the extra domain. Consequently, mediating the dynamics may offer a potential avenue to inhibit the SARS-CoV 3CLpro

31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

Withdrawal response in healthy adults

Abstract Background: Withdrawal response was used to explain extensor plantar response in population without pyramidal dysfunction but there is lack of data characterizing this response in normal population. Objective: To characterize withdrawal response from pain and tickle sensation in population without any neurological defi cit. Methods: The study was carried out using four different stimuli, namely heat-induced pain, cold-induced pain, electric-induced pain using electromyography stimulator and ticklish sensation using superworm (Zophobas morio), applied to normal subjects in University Malaya Medical Centre, Kuala Lumpur. Results: Heat-induced pain resulted in fl exion of the big toe (61.1%), other toes (62.3%), ankle dorsifl exion (82.6%), knee fl exion (83.9%) and hip fl exion (83.9%). Electric-induced pain showed fl exion of the big toe (27.7%), other toes (28.3%), ankle dorsifl exion (51.0%), knee fl exion (76.0%) and hip fl exion (76.0%). Ticklish sensation showed fl exion of the big toe (14.8%), other toes (14.8%), ankle dorsifl exion (22.7%), knee fl exion (21.9%), and hip fl exion (21.9%). There was signifi cant correlation between fear and ticklish sensation induced withdrawal responses and extension of big toe. Cold induced pain resulting in big toe fl exion (6.4%), other toes (6.9%), dorsifl exion of ankle (7.1%), fl exion of knee (6.9%), and hip fl exion (6.9%). Females were more responsive to heat, males to electrical stimulation. The prevalence of big toe extension ranged from 11.0% (electrical), 6.3% (ticklish), 4.8 (heat), to 0% (cold), a mean of 5.2% overall. Conclusion: Withdrawal response caused by nociceptive and ticklish sensation consists mostly of big toe fl exion and of other toes, ankle dorsifl exion and fl exion of the knee and hip. Extension of the big toe is seen in about 5% of all the stimulation