Comparative Safety of Pulsed Field Ablation and Cryoballoon Ablation Technologies for Pulmonary Vein Isolation in Patients with Paroxysmal Atrial Fibrillation: A Critical Literature Review and Indirect Treatment Comparison

INTRODUCTION

Cryoballoon ablation (CBA) is a standard catheter ablation technology with demonstrated clinical effectiveness for the treatment of paroxysmal atrial fibrillation (PAF); however, it can be associated with major adverse events, including phrenic nerve paralysis. Pulsed field ablation (PFA) is a novel, minimally thermal technology with comparable effectiveness and low safety risk. This study aimed to compare the safety profiles of PFA and CBA through critical analyses of the literature and indirect treatment comparisons.

METHODS

Studies were identified by searching the MEDLINE database and the Clinicaltrials.gov registry. Registered clinical trials and/or Food and Drug Administration Investigation Device Exemption (FDA IDE) studies evaluating PFA or CBA in adult patients with drug-refractory PAF between January 2008 and March 2023 were selected. Comparative safety between PFA and CBA was assessed for major and prespecified adverse events. Indirect comparisons were conducted using the proportion of patients experiencing adverse events and confirmed with single-arm meta-analyses and sensitivity analyses.

RESULTS

Data were extracted from three PFA publications including a total of 497 patients and six CBA studies including a total of 1113 patients. The analysis revealed that PFA was associated with significantly lower risk of major adverse events {risk difference - 4.3% [95% confidence interval (CI) - 5.8, - 2.8]; risk ratio 0.16 [95% CI 0.07, 0.45]} and prespecified adverse events [risk difference - 2.5% (95% CI - 4.4, - 0.5); risk ratio 0.53 (95% CI 0.31, 0.96)]. Meta-analyses confirmed the lower rate of major adverse events for PFA [0.4% (95% CI 0.0, 1.3)] vs. CBA [5.6% (95% CI 2.6, 8.6)] and prespecified adverse events for PFA [2.7% (95% CI 1.2, 4.1)] vs. CBA [5.8% (95% CI 2.7, 9.0)]. Sensitivity analyses exploring heterogeneity across studies confirmed robustness of the main analyses.

CONCLUSION

The findings of this study show that PFA has a more favorable safety profile than CBA, with significantly lower risks of major and prespecified adverse events. These indirect comparisons help contextualize the safety of PFA compared to CBA for the treatment of drug-refractory PAF in the absence of head-to-head studies.

Dual role of allele-specific DNA hypermethylation within the TERT promoter in cancer

Aberrant activation of telomerase in human cancer is achieved by various alterations within the TERT promoter, including cancer-specific DNA hypermethylation of the TERT hypermethylated oncological region (THOR). However, the impact of allele-specific DNA methylation within the TERT promoter on gene transcription remains incompletely understood. Using allele-specific next-generation sequencing, we screened a large cohort of normal and tumor tissues (n = 652) from 10 cancer types and identified that differential allelic methylation (DAM) of THOR is restricted to cancerous tissue and commonly observed in major cancer types. THOR-DAM was more common in adult cancers, which develop through multiple stages over time, than in childhood brain tumors. Furthermore, THOR-DAM was especially enriched in tumors harboring the activating TERT promoter mutations (TPMs). Functional studies revealed that allele-specific gene expression of TERT requires hypomethylation of the core promoter, both in TPM and TERT WT cancers. However, the expressing allele with hypomethylated core TERT promoter universally exhibits hypermethylation of THOR, while the nonexpressing alleles are either hypermethylated or hypomethylated throughout the promoter. Together, our findings suggest a dual role for allele-specific DNA methylation within the TERT promoter in the regulation of TERT expression in cancer.

DNA hypermethylation within TERT promoter upregulates TERT expression in cancer

Replicative immortality is a hallmark of cancer cells governed by telomere maintenance. Approximately 90% of human cancers maintain their telomeres by activating telomerase, driven by the transcriptional upregulation of telomerase reverse transcriptase (TERT). Although TERT promoter mutations (TPMs) are a major cancer-associated genetic mechanism of TERT upregulation, many cancers exhibit TERT upregulation without TPMs. In this study, we describe the TERT hypermethylated oncological region (THOR), a 433-bp genomic region encompassing 52 CpG sites located immediately upstream of the TERT core promoter, as a cancer-associated epigenetic mechanism of TERT upregulation. Unmethylated THOR repressed TERT promoter activity regardless of TPM status, and hypermethylation of THOR counteracted this repressive function. THOR methylation analysis in 1,352 human tumors revealed frequent (>45%) cancer-associated DNA hypermethylation in 9 of 11 (82%) tumor types screened. Additionally, THOR hypermethylation, either independently or along with TPMs, accounted for how approximately 90% of human cancers can aberrantly activate telomerase. Thus, we propose that THOR hypermethylation is a prevalent telomerase-activating mechanism in cancer that can act independently of or in conjunction with TPMs, further supporting the utility of THOR hypermethylation as a prognostic biomarker.

Thromboelastography as a Predictor of Outcomes Following Liver Transplantation

BACKGROUND

Thromboelastography (TEG) has been used perioperatively during liver transplantation (LT) to provide a real-time global hemostasis assessment for targeted blood product replacement. We aimed to analyze the relationship between post-LT TEG results and outcomes.

METHODS

We retrospectively analyzed patients undergoing LT from November 2008 to December 2014 at Mayo Clinic Florida. All 441 single-organ 1st-time LT patients aged ≥18 years requiring post-LT intensive care unit management were included. TEG parameters including r time, k time, α angle, and maximum amplitude were measured regularly during the first 24 hours after LT. Outcomes included return to the operating room secondary to bleeding, length of hospitalization, survival, and early allograft dysfunction.

RESULTS

A prolonged and/or lengthening r time, k time, and r+k time were all independently associated with increased length of hospitalization after LT. Increased maximum amplitude on the first post-LT TEG was associated with early allograft dysfunction. No notable associations of TEG parameters with survival or return to operating room were observed.

CONCLUSIONS

The association of absolute and temporal TEG value changes with increased length of hospitalization and early allograft dysfunction suggests that TEG may have a role in identifying patients at high risk for these outcomes.

Waitlist Outcomes for Patients Relisted Following Failed Donation After Cardiac Death Liver Transplant: Implications for Awarding Model for End-Stage Liver Disease Exception Scores

Understanding of outcomes for patients relisted for ischemic cholangiopathy following a donation after cardiac death (DCD) liver transplant (LT) will help standardization of a Model for End-Stage Liver Disease exception scheme for retransplantation. Early relisting (E-RL) for DCD graft failure caused by primary nonfunction (PNF) or hepatic artery thrombosis (HAT) was defined as relisting ≤14 days after DCD LT, and late relisting (L-RL) due to biliary complications was defined as relisting 14 days to 3 years after DCD LT. Of 3908 DCD LTs performed nationally between 2002 and 2016, 540 (13.8%) patients were relisted within 3 years of transplant (168 [4.3%] in the E-RL group, 372 [9.5%] in the L-RL group). The E-RL and L-RL groups had waitlist mortality rates of 15.4% and 10.5%, respectively, at 3 mo and 16.1% and 14.3%, respectively, at 1 year. Waitlist mortality in the L-RL group was higher than mortality and delisted rates for patients with exception points for both hepatocellular carcinoma (HCC) and hepatopulmonary syndrome (HPS) at 3- to 12-mo time points (p < 0.001). Waitlist outcomes differed in patients with early DCD graft failure caused by PNF or HAT compared with those with late DCD graft failure attributed to biliary complications. In L-RL, higher rates of waitlist mortality were noted compared with patients listed with exception points for HCC or HPS.

Noneligible Donors as a Strategy to Decrease the Organ Shortage

Organ procurement organization (OPO) performance is generally evaluated by the number of organ procurement procedures divided by the number of eligible deaths (donation after brain death [DBD] donors aged <70 years), whereas the number of noneligible deaths (including donation after cardiac death donors and DBD donors aged >70 years) is not tracked. The present study aimed to investigate the variability in the proportion of noneligible liver donors by the 58 donor service areas (DSAs). Patients undergoing liver transplant (LT) between 2011 and 2015 were obtained from the United Network for Organ Sharing Standard Transplant Analysis and Research file. LTs from noneligible and eligible donors were compared. The proportion of noneligible liver donors by DSA varied significantly, ranging from 0% to 19.6% of total liver grafts used. In transplant programs, the proportion of noneligible liver donors used ranged from 0% to 35.3%. On linear regression there was no correlation between match Model for End-Stage Liver Disease score for programs in a given DSA and proportion of noneligible donors used from the corresponding DSA (p = 0.14). Noneligible donors remain an underutilized resource in many OPOs. Policy changes to begin tracking noneligible donors and learning from OPOs that have high noneligible donor usage are potential strategies to increase awareness and pursuit of these organs.

Early Allograft Dysfunction After Liver Transplantation Is Associated With Short- and Long-Term Kidney Function Impairment

Early allograft dysfunction (EAD) after liver transplantation (LT) is related to ischemia-reperfusion injury and may lead to a systemic inflammatory response and extrahepatic organ dysfunction. We evaluated the effect of EAD on new-onset acute kidney injury (AKI) requiring renal replacement therapy within the first month and end-stage renal disease (ESRD) within the first year post-LT in 1325 primary LT recipients. EAD developed in 358 (27%) of recipients. Seventy-one (5.6%) recipients developed AKI and 38 (2.9%) developed ESRD. Compared with those without EAD, recipients with EAD had a higher risk of AKI and ESRD (4% vs. 9% and 2% vs. 6%, respectively, p < 0.001 for both). Multivariate logistic regression analysis showed an independent relationship between EAD and AKI as well as ESRD (odds ratio 3.5, 95% confidence interval 1.9-6.4, and odds ratio 3.1, 95% confidence interval 11.9-91.2, respectively). Patients who experienced both EAD and AKI had inferior 1-, 3-, 5-, and 10-year patient and graft survival compared with those with either EAD or AKI alone, while those who had neither AKI nor EAD had the best outcomes (p < 0.001). Post-LT EAD is a risk factor for both AKI and ESRD and should be considered a target for future intervention to reduce post-LT short- and long-term renal dysfunction.

The Use of Donation After Cardiac Death Allografts Does Not Increase Recurrence of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) recurrence in patients undergoing liver transplantation (LT) with donation after brain death (DBD) and donation after cardiac death (DCD) allografts has not previously been investigated. Rates and patterns of HCC recurrences were investigated in patients undergoing DBD (N = 1633) and DCD (N = 243) LT between 2003 and 2012. LT for HCC was identified in 397 patients (340 DBD and 57 DCD). No difference in tumor number (p = 0.26), tumor volume (p = 0.34) and serum alphafetoprotein (AFP) (p = 0.47) was seen between the groups. HCC recurrence was identified in 41 (12.1%) patients in the DBD group and 7 (12.3%) patients in the DCD group. There was no difference in recurrence-free survival (p = 0.29) or cumulative incidence of HCC recurrence (p = 0.91) between the groups. Liver allograft was the first site of recurrence in 22 (65%) patients in the DBD group and two (37%) patients in the DCD group (p = 0.39). LT for HCC with DBD and DCD allografts demonstrate no difference in the rate of HCC recurrence. Previously published differences in survival demonstrated between recipients with HCC receiving DBD and DCD allografts despite statistical adjustment can likely be explained by practice patterns not captured by variables contained in the SRTR database.

Characteristic dermoscopic features of primary cutaneous amyloidosis: a study of 35 cases

BACKGROUND

Primary cutaneous amyloidosis (PCA) is a relatively common skin disorder among Asians and South Americans. It is usually diagnosed clinically. However, for cases with atypical presentations, the diagnosis can be a challenge and skin biopsy may be necessary. Dermoscopy has been proved to be a valuable, noninvasive tool in the diagnosis of cutaneous pigmented diseases. Most lesions of PCA show hyperpigmentation and the major histopathological abnormalities of PCA occur in the epidermis and dermal papillae. Dermoscopy might be a powerful tool to provide valuable information for the diagnosis of PCA.

OBJECTIVES

We aimed to find characteristic dermoscopic features of PCA.

MATERIALS AND METHODS

Cases with typical clinical presentations of PCA, either macular or lichen subtypes, were included in this study. All were evaluated using a hand-held, polarized and nonpolarized dermoscope.

RESULTS

A total of 35 patients with clinically diagnosed PCA were enrolled. Eighteen patients had lesions consistent with macular amyloidosis and 17 with lichen amyloidosus. We found two major dermoscopic patterns characteristic of PCA. The most common dermoscopic finding of PCA was a central hub, which could be either white or brown, surrounded by various configurations of pigmentation. For cases of lichen amyloidosus with prominent hyperkeratosis, the central hub was replaced by a scar-like morphology.

CONCLUSIONS

This is the first study to report the characteristic dermoscopic features of PCA. We demonstrate that the use of a dermoscope may assist in achieving an accurate diagnosis of PCA.

Malignancies associated with dermatomyositis and polymyositis in Taiwan: a nationwide population-based study

BACKGROUND

Previous studies showed that idiopathic inflammatory myopathies (IIM) carried an increased risk of cancers. However, no large-scale study of IIM has been conducted in the Chinese population.

OBJECTIVES

We sought to delineate the association of IIM and various cancer types from a nationwide database in Taiwan.

METHODS

We analysed the published national data from records of National Health Insurance claims. Cases of dermatomyositis (DM) and polymyositis (PM) from 2000 to 2005 and cancers registered in the catastrophic illness profile from 1997 to 2006 were collected. A nationally representative cohort of 1,000,000 enrollees was included for comparison.

RESULTS

In total, 136 patients (12.8%) among 1059 cases of DM and 46 persons (7.0%) among 661 cases of PM carried internal malignancies. Patients with DM tended to have cancers of nasopharynx, lung and breast. On the other hand, patients with PM tended to have breast, uterine cervix and lung cancers. Compared with the general population, DM gave a 10-fold increased risk for cancers, in which a 66-fold increased risk for nasopharyngeal carcinoma and a 31-fold increased risk for lung cancer were the two most significant. For patients with PM, a 6-fold increased risk for cancer was observed. Juvenile DM had a 16-fold increased risk for haematopoietic or lymphoid malignancy. Two thirds of comorbid malignancies were detected shortly after the diagnoses of IIM, within a mean of 1-2 years. Overall, younger patients with IIM carried the highest risk for malignancies, especially those in their twenties and thirties.

CONCLUSIONS

This is the first large-scale study to report the associated malignancies and the cancer risk of IIM in Taiwan.

Cellular therapies for type 1 diabetes

Type 1 diabetes mellitus (T1DM) is a disease that results from the selective autoimmune destruction of insulin-producing beta-cells. This disease process lends itself to cellular therapy because of the single cell nature of insulin production. Murine models have provided opportunities for the study of cellular therapies for the treatment of diabetes, including the investigation of islet transplantation, and also the possibility of stem cell therapies and islet regeneration. Studies in islet transplantation have included both allo- and xeno-transplantation and have allowed for the study of new approaches for the reversal of autoimmunity and achieving immune tolerance. Stem cells from hematopoietic sources such as bone marrow and fetal cord blood, as well as from the pancreas, intestine, liver, and spleen promise either new sources of islets or may function as stimulators of islet regeneration. This review will summarize the various cellular interventions investigated as potential treatments of T1DM.

Cytokine gene polymorphisms in Chinese patients with psoriasis

BACKGROUND

Previous studies have shown that cytokine gene polymorphisms may confer susceptibility to psoriasis.

OBJECTIVES

To determine whether genetic polymorphisms of the cytokine genes might influence the development of psoriasis in Chinese patients in Taiwan.

METHODS

DNA samples were obtained from 170 patients with psoriasis vulgaris (PV), 102 patients with psoriatic arthritis (PsA) and 210 control subjects. Using direct sequencing and microsatellite genotyping, we examined 28 polymorphisms in 11 cytokine genes including the interleukin (IL)-1alpha, IL-1beta, IL-1 receptor antagonist, IL-4, IL-8, IL-10, IL-12B, IL-13, tumour necrosis factor (TNF)-alpha, TNF-beta and interferon-gamma genes. Genotypes of HLA-Cw*0602, killer cell immunoglobulin-like receptor (KIR) genes and major histocompatibility complex class I chain-related gene A (MICA) were also determined in patients with PsA.

RESULTS

The patients with PV were more likely to carry the +4496G allele of the IL-12B gene (59.4% vs. 49.3%, P = 0.0067, P(c) = 0.033). However, no significantly different allelic and genotypic distributions of the other analysed genes including IL-1beta, TNF-alpha, TNF-beta, KIR genes and MICA were found between the PV/PsA patients and controls. Moreover, no association was observed with disease onset, gender, peripheral arthritis or joint erosion. With regards to HLA-Cw*0602, its allele frequency was significantly increased in patients with early-onset PV (25.3% vs. 4.8%, P < 10(-7)), but not in patients with PsA.

CONCLUSIONS

The IL-12B gene polymorphism conferred a risk for PV in our Chinese population, although the effect was more minor than that of HLA-Cw*0602. Cw*0602, KIR2DS1/S2 and MICA-A9 were unlikely to be risk alleles in our patients with PsA. The other analysed genetic polymorphisms of cytokine genes do not appear to be associated with susceptibility to PV and PsA in Chinese patients in Taiwan.

Psoriasis vulgaris in Chinese individuals is associated withPSORS1C3andCDSNgenes

BACKGROUND

Besides the HLA-Cw*0602 allele, the psoriasis susceptibility 1 candidate 3 (PSORS1C3) and corneodesmosin (CDSN) genes are two probable psoriasis susceptibility genes in the PSORS1 locus. The -79C, -26C and +246A alleles of the PSORS1C3 gene, the CDSN*971T allele, CDSN*TTC (619T-1236T-1243C) and CDSN*5 (619T-1240G-1243C) are strongly associated with psoriasis in the caucasian population. Until now, no haplotype study of the PSORS1C3 and CDSN genes has been documented in Chinese patients with psoriasis vulgaris.

OBJECTIVES

We aimed to determine whether genetic polymorphisms of the PSORS1C3 and CDSN genes were associated with an increased risk of psoriasis vulgaris in Chinese patients in Taiwan.

METHODS

We investigated the PSORS1C3 and CDSN genes for disease association by direct sequencing in 178 patients with psoriasis vulgaris and 203 control subjects. Genotyping for HLA-Cw*0602, alpha-helix coiled-coil rod homologue (HCR) gene and single nucleotide polymorphism (SNP) n.9 was also carried out using a sequence-based typing method.

RESULTS

The PSORS1C3*582A allele, an SNP in the 3'-untranslated region of the PSORS1C3 gene, was a major psoriasis vulgaris susceptibility allele in the Chinese population, and the association was much stronger in patients with early-onset psoriasis vulgaris (22.3% vs. 6.9%, odds ratio = 3.87, P(c) =0.0000072). The frequencies of CDSN*TTC and CDSN*971T were also significantly increased in patients with early-onset psoriasis vulgaris. Moreover, PSORS1C3*582A, SNP n.9*C, Cw*0602 and HCR*WWCC were in near complete linkage disequilibrium (LD) with each other; in contrast, the LD with the CDSN gene was not so strong. SNP n.9*C-Cw*0602-PSORS1C3*582A-HCR*WWCC was a major susceptibility haplotype in patients with early-onset psoriasis vulgaris (P < 10(-7)) and this risk haplotype also carried CDSN*TTC and CDSN*971T.

CONCLUSIONS

The PSORS1C3 and CDSN genes are important psoriasis susceptibility genes in Chinese patients with psoriasis vulgaris.

No association of cytokine gene polymorphisms in Chinese patients with atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is a common chronically relapsing skin disease associated with the activation of T-helper 2 cells. Recent studies have shown that polymorphisms in the genes for interleukin (IL)-4, the IL-4 receptor, IL-13, and signal transducer and activator 6 (STAT6) may contribute to susceptibility of AD. To date, no cytokine gene polymorphism study has been conducted on Chinese patients with AD.

AIMS

To determine whether genetic polymorphisms of the cytokine genes might influence the development of AD.

METHODS

DNA samples were obtained from 94 patients and 186 control subjects. Using direct sequencing and microsatellite genotyping, we examined 22 polymorphisms in eight cytokine genes including the genes for IL-4, -10, -12B and -13, the IL-4 receptor, tumour necrosis factor (TNF)-alpha, STAT6, and interferon (IFN)-gamma.

RESULTS

No significantly different allelic and genotypic distributions of the cytokine gene polymorphisms could be found between patients and controls. Moreover, no association was observed with disease onset, gender, the presence of elevated serum total IgE level or blood eosinophilia.

CONCLUSION

Our study suggests that the analysed genetic polymorphisms of cytokine genes do not appear to be associated with AD susceptibility in our Chinese population.

A study of PSORS1C1 gene polymorphisms in Chinese patients with psoriasis

BACKGROUND

Although genetic analyses have identified the HLA-Cw*0602 allele as the major risk allele for chronic plaque psoriasis in various ethnic groups, it has been proposed that the association of Cw*0602 is due to linkage disequilibrium and that other nearby genes are involved in susceptibility to psoriasis. The psoriasis susceptibility 1 candidate 1 (PSORS1C1, formerly SEEK1) gene, located 127 kb telomeric to the HLA-C locus, is considered to be one of the potential candidate genes of psoriasis. Up to the present, no association study of the PSORS1C1 gene has been conducted on Chinese patients with psoriasis.

OBJECTIVES

We aimed to determine whether the genetic polymorphisms of the PSORS1C1 gene were associated with an increased risk of psoriasis in Chinese patients.

METHODS

We investigated the PSORS1C1 gene for disease association by direct sequencing of the PSORS1C1 gene in 143 Chinese patients with chronic plaque psoriasis and 188 control subjects. Genotyping for HLA-Cw*0602 and the alpha-helix coiled-coil rod homologue (C6orf18, formerly HCR) gene was also carried out using a sequence-based typing method.

RESULTS

We identified 10 single nucleotide polymorphisms (SNPs) on the PSORS1C1 gene in our subjects; four of these SNPs cause amino acid change. We also detected poly(C) repeat variants from nucleotide positions 386-392 (poly(C)6-8). The poly(C) repeat polymorphisms cause a frame shift mutation. Another poly(C) repeat variant was also found at nucleotide positions 748-751. No significantly different allelic distributions of the PSORS1C1 SNPs or poly(C) repeat polymorphisms could be found between the patients with chronic plaque psoriasis and controls after correction for multiple testing. However, a significant increase of the Cw*0602 allele and tryptophan-tryptophan allele of the C6orf18 gene (HCR*WW) was found in patients with early onset psoriasis (21.9% vs. 4.8%, P < 10(-7)). Haplotype-based association analysis also showed a susceptibility haplotype carrying Cw*0602 and HCR*WW alleles in early onset Chinese patients.

CONCLUSIONS

Our results indicate that the PSORS1C1 gene might not play an important role in the causation of chronic plaque psoriasis in Chinese people.

Cytokine gene polymorphisms in bullous pemphigoid in a Chinese population

BACKGROUND

Bullous pemphigoid (BP) is an autoimmune bullous disease mostly associated with autoantibodies to the hemidesmosomal BP autoantigens BP180 and BP230. High levels of interleukin (IL)-1beta, IL-4, IL-5, IL-6, IL-8, IL-10, IL-13, tumour necrosis factor (TNF)-alpha and interferon (IFN)-gamma have been detected in skin lesions or sera of patients with BP. Cytokine gene polymorphisms may affect cytokine production and contribute to susceptibility to autoimmune diseases. Until now, no cytokine gene polymorphism study has been conducted on patients with BP.

OBJECTIVES

We aimed to determine whether the genetic polymorphisms of the cytokine genes might influence the development of BP.

METHODS

DNA samples were obtained from 96 BP patients and 174 control subjects. Using direct sequencing and microsatellite genotyping, we examined 23 polymorphisms in 11 cytokine genes including the IL-1alpha, IL-1beta, IL-1 receptor antagonist, IL-4, IL-6, IL-8, IL-10, IL-13, IL-4 receptor, TNF-alpha and IFN-gamma genes.

RESULTS

Although the BP patients were more likely to carry the -511T and -31C alleles of the IL-1beta gene (P = 0.04), the significance disappeared after correction for multiple testing (Pc). There was complete linkage disequilibrium between the -511T and -31C alleles of the IL-1beta gene. In female patients with BP, the associations with IL-1beta (-511T) and (-31C) alleles were much stronger (68% vs. 40.6%, odds ratio = 3.11, Pc = 0.006). No significantly different allelic and genotypic distributions of other cytokine gene polymorphisms could be found between the patients with BP and controls. Moreover, no association with the extent of disease involvement (localized or generalized) was observed.

CONCLUSIONS

The IL-1beta (-511) and (-31) polymorphisms were significantly associated with BP in women. The other genetic polymorphisms of cytokine genes that we analysed do not appear to be associated with BP susceptibility in our Chinese population.

A study of cytokeratin profiles in localized cutaneous amyloids

The major component of localized cutaneous amyloids may be derived from cytokeratin (CK). However, the CK profiles of primary cutaneous amyloidosis (PCA) and secondary cutaneous amyloidosis (SCA) remain obscure. Paraffin-embedded sections of skin tissue from 64 patients with PCA, 111 with SCA and 3 with systemic amyloidosis were analyzed immunohistochemically using 12 different polyclonal or monoclonal anti-CK antibodies (34betaE12, MNF116, LP34, AE1/AE3, anti-CK1, CK5, CK6, CK7, CK10, CK14, CK16 and CK17). In addition, frozen skin tissues from 12 patients with PCA were analyzed for comparison with the paraffin-embedded tissue. In all 64 PCA paraffin sections, the amyloid deposits were immunopositive for anti-CK5 antibody and 34betaE12. In all 12 frozen sections of PCA, the amyloid deposits were immunopositive for anti-CK5 antibody, 34betaE12, MNF116 and LP34, and seven (58.3%), three (25%) and one (8.3%) were immunopositive for anti-CK1, CK14, and CK10 antibodies, respectively. In all SCA sections, the amyloid deposits were immunopositive for CK5 and 34betaE12. In addition, MNF116 immunolabeled amyloids of all sections from patients with basal cell carcinoma and trichoepithelioma, and MNF116 and LP34 immunolabeled amyloids of sections from patients with porokeratosis. Our results indicate that CK5 is the major CK present in the amyloid deposits of PCA and SCA, and "amyloid-K" is mainly derived from basal keratinocytes.

Spontaneous eye movements in goldfish: oculomotor integrator performance, plasticity, and dependence on visual feedback

To quantify performance of the goldfish oculomotor neural integrator and determine its dependence on visual feedback, we measured the relationship between eye drift-velocity and position during spontaneous gaze fixations in the light and in the dark. In the light, drift-velocities were typically less than 1 deg/s, similar to those observed in humans. During brief periods in darkness, drift-velocities were only slightly larger, but showed greater variance. One hour in darkness degraded fixation-holding performance. These findings suggest that while visual feedback is not essential for online fixation stability, it may be used to tune the mechanism of persistent neural activity in the oculomotor integrator.

SPR1 gene near HLA-C is unlikely to be a psoriasis susceptibility gene

Although genetics analyses have identified the HLA-Cw6 allele to be the major risk allele for psoriasis vulgaris (PV) in many racial groups, it has been proposed that other putative genes near the HLA-C locus are involved in PV susceptibility and that the association of Cw6 is a result of linkage disequilibrium. The SPR1 gene, a predicted gene located 128 kb telomeric to the HLA-C locus, is considered to be one potential candidate gene of PV. Until now, no association study of the SPR1 gene has been conducted on psoriasis patients. We investigated the SPR1 gene for disease association by direct sequencing of the SPR1 gene in 116 Chinese patients with PV and 116 normal subjects. Genotyping for HLA-Cw6 was also carried out using polymerase chain reaction/restriction fragment length polymorphism. Significant increase of the HLA-Cw6 allele was found in psoriasis patients (32.8% vs. 13.8%, P = 0.001). We found that the SPR1 gene is a highly polymorphic gene containing 13 single nucleotide polymorphisms (SNPs), two of which have not been previously reported, and four SNPs cause amino acid change. No significantly different allelic distribution of 13 SPR1 SNPs could be found between the patients with PV and controls after correction for multiple testing. If the frequencies of SPR1 SNPs were compared between the early onset psoriatics and control subjects, early onset patients were more likely to have G allele at position 988 (60% vs. 35.3%, P = 0.001). However, the significance disappeared upon stratification for the Cw6 status. Haplotype-based association analysis showed two susceptibility haplotypes (types 8 and 19) in early onset psoriasis patients. Nonetheless, the significance also disappeared after stratification of the Cw6 status. Our results suggest that HLA-Cw6 remains the major risk allele in Chinese psoriatics, and that the SPR1 gene might not play an important role in the causation of PV.

A study of candidate genes for psoriasis near HLA-C in Chinese patients with psoriasis

BACKGROUND

Genetic analyses have identified the HLA-Cw6 allele as the major risk allele for psoriasis in many racial groups. However, by serological typing, HLA-Cw6 is not considered a risk factor in Chinese psoriatics. There are several susceptibility genes for psoriasis residing in chromosome 6p near the HLA-C locus, including the corneodesmosin (CDSN) gene, the octamer transcription factor-3 (POU5F1) gene, the major histocompatibility complex class I chain-related gene A (MICA), and the gene for tumour necrosis factor (TNF)-alpha. However, the information about their role in psoriasis in Chinese patients is limited.

OBJECTIVES

We aimed to determine whether Cw6 and the genetic polymorphism of the CDSN gene, POU5F1 gene, MICA gene and the gene for TNF-alpha promoter region were associated with an increased risk of psoriasis in Chinese patients.

METHODS

We conducted a case-control association study in 105 Chinese patients with psoriasis vulgaris and 160 control subjects of similar ages. Genotypes of Cw6, the CDSN gene, the POU5F1 gene, and the gene for the TNF-alpha promoter region were determined by polymerase chain reaction (PCR) followed by restriction enzyme digestion. Genotyping of MICA was determined by PCR combined with fluorescent-based automated fragment detection technology. Results The allele frequencies showed no differences between patients and controls for the POU5F1 gene, MICA gene and the gene for TNF-alpha promoter region. The frequency of the HLA-Cw6 allele in the psoriasis group was significantly higher than that in the control group (18.6% vs. 6.56%, P < 0.00005). For the CDSN gene, patients were more likely to have C allele at position +619 (P = 0.006) and C allele at position +1243 (P = 0.007), but the significance disappeared after correction for multiple testing (Pc > 0.05).

CONCLUSIONS

HLA-Cw6 remains the most significant susceptibility gene in Chinese patients with psoriasis. However, the role of the CDSN gene in the pathogenesis of psoriasis deserves further scrutiny.

Clinical and histopathological characteristics of primary cutaneous amyloidosis in 794 Chinese patients

BACKGROUND

Primary cutaneous amyloidosis (PCA) is not uncommon in Chinese patients. The disease is usually persistent and quite pruritic. Patients who suffer from this disease usually respond poorly to conventional treatment. We thus reviewed our cases of PCA to discuss the clinical and pathological characteristics.

METHODS

Seven hundred and ninety-four Chinese patients with PCA who visited the Department of Dermatology, Taipei Veterans General Hospital during the last 26-year period were examined and retrospectively studied. The diagnosis in these patients was confirmed by histopathological studies.

RESULTS

Among the many types of PCA, lichen amyloidosis was the most common clinical variant (67%). Pure cases of macular amyloidosis accounted only 8% and were often associated with lichenoid lesions to form biphasic amyloidosis, which was composed of 25% in our series. Other rare types of PCA, such as nodular, anosacral, and vitiliginous amyloidosis, always required a careful differential diagnosis clinically from other similar skin disorders. In addition, 56 familial cases were found. Histopathologically, the most common epidermal findings of PCA were hyperkeratosis, irregular acanthosis with thinning of rete ridges, and expansion of dermal papillae by amyloid deposition. Special histochemical stains were helpful for confirming the existence of amyloid.

CONCLUSIONS

Our study represents the largest number of cases of PCA collected to date. Based on the data, most cases are sporadic, except 56 familial cases which may suggest the possible genetic role. Rare types of PCA, such as anosacral and vitiliginous amyloidosis which need special attention, compose a diagnostic challenge to a dermatologist. Histochemically, H&E stain can give a primary clue for the diagnosis of amyloidosis and crystal violet stain is a very simple and sensitive method to detect the existence of amyloid.

Equilibrium properties of temporally asymmetric Hebbian plasticity

A theory of temporally asymmetric Hebb rules, which depress or potentiate synapses depending upon whether the postsynaptic cell fires before or after the presynaptic one, is presented. Using the Fokker-Planck formalism, we show that the equilibrium synaptic distribution induced by such rules is highly sensitive to the manner in which bounds on the allowed range of synaptic values are imposed. In a biologically plausible multiplicative model, the synapses in asynchronous networks reach a distribution that is invariant to the firing rates of either the presynaptic or postsynaptic cells. When these cells are temporally correlated, the synaptic strength varies smoothly with the degree and phase of their synchrony.

Cognition. The manifold ways of perception

One of the great puzzles of visual perception is how an image that is in perpetual flux can still be seen by the observer as the same object. In an informative Perspective, Seung and Lee explain the mathematical intricacies of two new algorithms for modeling the variability of perceptual stimuli and other types of high-dimensional data (Tenenbaum et al., and Roweis and Saul).

The autapse: a simple illustration of short-term analog memory storage by tuned synaptic feedback

According to a popular hypothesis, short-term memories are stored as persistent neural activity maintained by synaptic feedback loops. This hypothesis has been formulated mathematically in a number of recurrent network models. Here we study an abstraction of these models, a single neuron with a synapse onto itself, or autapse. This abstraction cannot simulate the way in which persistent activity patterns are distributed over neural populations in the brain. However, with proper tuning of parameters, it does reproduce the continuously graded, or analog, nature of many examples of persistent activity. The conditions for tuning are derived for the dynamics of a conductance-based model neuron with a slow excitatory autapse. The derivation uses the method of averaging to approximate the spiking model with a nonspiking, reduced model. Short-term analog memory storage is possible if the reduced model is approximately linear and if its feedforward bias and autapse strength are precisely tuned.

Resorbable calcium phosphate bone substitute

The in vitro and in vivo properties of a novel, fully resorbable, apatitic calcium phosphate bone substitute (ABS) are described. The ABS was prepared from calcium phosphate precursors that were hydrated to form an injectable paste that hardens endothermically at 37 degrees C to form a poorly crystalline apatitic calcium phosphate (PCA). The PCA reaction product is stable in vivo as determined by FTIR and XRD analysis of rabbit intramuscular implants of ABS retrieved 4, 7, and 14 days postimplantation. Bone formation and resorption characteristics of the ABS material were characterized in a canine femoral slot defect model. Femoral slot defects in dogs were filled with either autologous bone implants or the ABS material. Sections of femoral bone defect site from animals sacrificed at 3, 4, 12, 26, and 52 weeks demonstrated that new bone formation proceeded similarly in both autograft and ABS filled slots. Defects receiving either material were filled with trabecular bone in the first 3 to 4 weeks after implantation; lamellar or cortical bone formation was well established by week 12. New bone formation in ABS filled defects followed a time course comparable to autologous bone graft filled defects. Histomorphometric evaluation of ABS resorption and new bone formation indicated that the ABS material was greater than 99% resorbed within 26 weeks; residual ABS occupied 0.36+/-0.36% (SEM, n = 4) of the original defect area at 26 weeks. Quantitatively and qualitatively, the autograft and ABS were associated with similar new bone growth and defect filling characteristics.

Comparison of pharmacokinetics of fentanyl after intravenous and transdermal administration in cats

OBJECTIVE

To compare pharmacokinetic and pharmacodynamic characteristics of fentanyl citrate after IV or transdermal administration in cats.

ANIMALS

6 healthy adult cats with a mean weight of 3.78 kg.

PROCEDURE

Each cat was given fentanyl IV (25 mg/cat; mean +/- SD dosage, 7.19 +/- 1.17 mg/kg of body weight) and via a transdermal patch (25 microg of fentanyl/h). Plasma concentrations of fentanyl were measured by use of radioimmunoassay. Pharmacokinetic analyses of plasma drug concentrations were conducted, using an automated curve-stripping process followed by nonlinear, least-squares regression. Transdermal delivery of drug was calculated by use of IV pharmacokinetic data.

RESULTS

Plasma concentrations of fentanyl given IV decreased rapidly (mean elimination half-life, 2.35 +/- 0.57 hours). Mean +/- SEM calculated rate of transdermal delivery of fentanyl was 8.48 +/- 1.7 mg/h (< 36% of the theoretical 25 mg/h). Median steady-state concentration of fentanyl 12 to 100 hours after application of the transdermal patch was 1.58 ng/ml. Plasma concentrations of fentanyl < 1.0 ng/ml were detected in 4 of 6 cats 12 hours after patch application, 5 of 6 cats 18 and 24 hours after application, and 6 of 6 cats 36 hours after application.

CONCLUSIONS AND CLINICAL RELEVANCE

In cats, transdermal administration provides sustained plasma concentrations of fentanyl citrate throughout a 5-day period. Variation of plasma drug concentrations with transdermal absorption for each cat was pronounced. Transdermal administration of fentanyl has potential for use in cats for long-term control of pain after surgery or chronic pain associated with cancer.

Coding and noncoding variation of the human calcium-channel beta4-subunit gene CACNB4 in patients with idiopathic generalized epilepsy and episodic ataxia

Inactivation of the beta4 subunit of the calcium channel in the mouse neurological mutant lethargic results in a complex neurological disorder that includes absence epilepsy and ataxia. To determine the role of the calcium-channel beta4-subunit gene CACNB4 on chromosome 2q22-23 in related human disorders, we screened for mutations in small pedigrees with familial epilepsy and ataxia. The premature-termination mutation R482X was identified in a patient with juvenile myoclonic epilepsy. The R482X protein lacks the 38 C-terminal amino acids containing part of an interaction domain for the alpha1 subunit. The missense mutation C104F was identified both in a German family with generalized epilepsy and praxis-induced seizures and in a French Canadian family with episodic ataxia. These coding mutations were not detected in 255 unaffected control individuals (510 chromosomes), and they may be considered candidate disease mutations. The results of functional tests of the truncated protein R482X in Xenopus laevis oocytes demonstrated a small decrease in the fast time constant for inactivation of the cotransfected alpha1 subunit. Further studies will be required to evaluate the in vivo consequences of these mutations. We also describe eight noncoding single-nucleotide substitutions, two of which are present at polymorphic frequency, and a previously unrecognized first intron of CACNB4 that interrupts exon 1 at codon 21.

Stability of the memory of eye position in a recurrent network of conductance-based model neurons

Studies of the neural correlates of short-term memory in a wide variety of brain areas have found that transient inputs can cause persistent changes in rates of action potential firing, through a mechanism that remains unknown. In a premotor area that is responsible for holding the eyes still during fixation, persistent neural firing encodes the angular position of the eyes in a characteristic manner: below a threshold position the neuron is silent, and above it the firing rate is linearly related to position. Both the threshold and linear slope vary from neuron to neuron. We have reproduced this behavior in a biophysically plausible network model. Persistence depends on precise tuning of the strength of synaptic feedback, and a relatively long synaptic time constant improves the robustness to mistuning.

C(60) and water-soluble fullerene derivatives as antioxidants against radical-initiated lipid peroxidation

C(60), vitamin E, and three C(60) derivatives (polar 1 and water-soluble C(3)/D(3)C(60)s) were examined for their antioxidant effects on prevention of lipid peroxidation induced by superoxide and hydroxyl radicals. The protection effect on lipid peroxidation was found to be in the sequence: C(60) >/= vitamin E > 1 > none, for liposoluble antioxidants, and C(3)C(60) >> D(3)C(60) > none, for water-soluble ones. Fluorescence quenching of PyCH(2)COOH (Py = pyrene) by both C(3)- and D(3)C(60)s shows that the Stern-Volmer constant, K(SV), is about the same for both quenchers in aqueous solution. Upon addition of liposomes, the fluorescence quenching becomes more efficient: 5-fold higher in K(SV) for C(3)C(60) than for D(3)C(60). When Py(CH(2))(n)()COOH (n = 1, 3, 5, 9, or 15) was incorporated in lipid membranes, the K(SV)s all were small and nearly equal for D(3)C(60) but were quite large and different for C(3)C(60) with the sequence: n = 1 < 3 < 5 < 9 < 15. The better protection effect of C(3)C(60) on lipid peroxidation than that of D(3)C(60) is attributed to its stronger interaction with membranes. Overall, the antioxidation abilities of the compounds examined were rationalized in terms of the number of reactive sites, the location of antioxidant in lipid membranes, and the strength of interactions between antioxidants and membranes.

Learning the parts of objects by non-negative matrix factorization

Is perception of the whole based on perception of its parts? There is psychological and physiological evidence for parts-based representations in the brain, and certain computational theories of object recognition rely on such representations. But little is known about how brains or computers might learn the parts of objects. Here we demonstrate an algorithm for non-negative matrix factorization that is able to learn parts of faces and semantic features of text. This is in contrast to other methods, such as principal components analysis and vector quantization, that learn holistic, not parts-based, representations. Non-negative matrix factorization is distinguished from the other methods by its use of non-negativity constraints. These constraints lead to a parts-based representation because they allow only additive, not subtractive, combinations. When non-negative matrix factorization is implemented as a neural network, parts-based representations emerge by virtue of two properties: the firing rates of neurons are never negative and synaptic strengths do not change sign.

alpha-BSM: a biomimetic bone substitute and drug delivery vehicle

alpha-BSM is a biomimetic endothermically setting apatitic calcium phosphate bone substitute material. Its injectability and ability to harden at body temperature in the presence of physiologic saline, and other buffering agents, makes it an attractive clinical bone substitute and delivery vehicle for therapeutic agents in orthopaedic and dental applications. In osseous tissue, alpha-BSM alone remodels into bone and promotes bone healing. alpha-BSM treatment has been shown in several animal models to be effective in promoting healing of surgically created critical size defects and restoring bone biomechanical strength to values equal to or greater than values achieved with autograft controls. In vitro studies with alpha-BSM containing gentamicin show that antibiotics can be incorporated stably into alpha-BSM and that the release kinetics can be controlled with the appropriate formulation and preparative procedures. Growth factors and enzymes also are compatible with the alpha-BSM setting reaction. The incorporation of recombinant human bone morphogenetic protein-2 with alpha-BSM was shown to be effective in stimulating bone formation and accelerating restoration of the differentiated phenotype in an osteotomy model. Clinical trial investigators in Europe currently are using alpha-BSM implantations for treatment of fractures and other indications.

Complications of osteotomies in severe cerebral palsy

Seventy-nine consecutive children with cerebral palsy who underwent osteotomies about the hip for subluxation or dislocation were studied retrospectively to determine risk factors that would correlate with postoperative complications of death, fracture, or decubitus ulcer. Except for the three patients who died, all of the children had > or = 1 year of follow-up. Twenty (25%) patients had at least one complication. Three children died; one at 1 week, one at 2 weeks, and one at 5 months after surgery. Sixteen patients sustained 25 fractures. All were managed with cast or splint immobilization in the clinic. Five patients developed decubitus ulcers requiring > or = 2 weeks of local care, but none required skin grafts or flaps. Complications occurred in 13 (68%) of 19 children with gastrostomies or tracheostomies but in only seven (12%) of the remaining 60 children. Only one (8%) of 13 ambulatory patients had a complication compared with 19 (29%) of 66 nonambulatory patients. In conclusion, ambulatory function correlates well with the risk of complications after osteotomies. A nonambulatory patient with a gastrostomy or tracheostomy is at even greater risk. Fortunately the fractures and ulcers observed in this series healed uneventfully with no operative intervention.

Dermatopathologic findings in 20 cases of systemic amyloidosis

The clinical findings of systemic amyloidosis are often variable and nonspecific. The early recognition of this disorder relies upon clinical suspicion, and definite diagnosis requires the confirmation of amyloid deposits in tissue. We reviewed 31 skin biopsy specimens from 20 patients, including 17 with amyloid light chain (AL) protein amyloidosis and 3 with serum amyloid A (AA) protein amyloidosis. Histologically, amyloid can be present in the papillary dermis, reticular dermis, subcutis, around the appendages, and in or around blood vessels. In our series, all 20 patients had at least one positive skin biopsy. Amyloid was found in 30 of 31 specimens (97%), a higher rate than in most series. Skin biopsy is a simple, safe procedure with high yield and may be used to obtain a firm diagnosis of systemic amyloidosis.

High-resolution zero-dispersion wavelength mapping in single-mode fiber

We present a new noninvasive technique for measuring the spatial variation of the zero-dispersion wavelength (lambda(0)) in single-mode fibers. This technique uses low-power continuous-wave lasers and is simple to implement. When applying this technique to dispersion-shifted fibers, we can resolve subnanometer fluctuations in lambda(0) with a potential spatial resolution of better than 100 m. We also discuss and show the limits of this and other techniques that arise from polarization-mode dispersion in the fibers.

Respiratory depressant and skeletal muscle relaxant effects of low-dose pancuronium bromide in spontaneously breathing, isoflurane-anesthetized dogs

OBJECTIVE

To assess and compare the respiratory depressant and skeletal muscle relaxant effects of two low doses of a nondepolarizing neuromuscular blocker, pancuronium bromide. To determine if a "low dose" of pancuronium bromide can produce selective skeletal muscle relaxation in extraocular muscles sufficient to perform intraocular surgery while sparing or minimizing depression of muscles of ventilation.

STUDY DESIGN

Blinded, randomized crossover, placebo controlled study.

ANIMALS

Six healthy, adult mongrel dogs weighing 20.8 +/- 1.9 kg.

METHODS

Spontaneously breathing, isoflurane-anesthetized dogs received 0.02 mg/kg pancuronium bromide, intravenously (i.v.), (high dose [HD]), 0.01 mg/kg pancuronium bromide, i.v., (low dose [LD]), or saline placebo i.v. in a blinded, randomized crossover study. Indices of patient ventilation including tidal volume (Vt), respiratory rate (RR), and minute ventilation (VE) were recorded throughout the study period. Serial arterial blood gas analyses were performed at timed intervals. Neuromuscular blockade of skeletal muscle was assessed at timed intervals with train-of-four stimulus/response ratios. Eye position scores, based on the degree of ocular rotation from a neutral gaze axis, were assigned by an ophthalmologist who was blinded to the treatment given.

RESULTS

VT and VE in HD dogs decreased by 82% from baseline after administration of pancuronium bromide. Similarly, Vt and VE in LD dogs decreased 40% and 55%, respectively. Decreased ventilation in HD dogs corresponded with significant (P< .05) neuromuscular blockade, as indicated by train-of-four ratio less than 75% between 0 and 60 minutes. Eye position scores in HD and LD dogs were suitable for intraocular surgery between 0 and 60 minutes. Eye position scores in five of six control dogs were unsuitable for intraocular surgery at any time period.

CONCLUSIONS

LD dogs experienced only transient, mild to moderate respiratory depression compared with HD dogs, which experienced prolonged, moderate to severe respiratory depression. Both LD and HD dogs acquired and maintained eye position scores suitable for intraocular surgery between 0 to 60 minutes. A "low dose" of pancuronium bromide, which would provide adequate extraocular muscle relaxation while minimizing ventilatory depression, was not identified.

CLINICAL RELEVANCE

All patients receiving any dose of neuromuscular blocking agents should be closely monitored and receive ventilatory assistance as needed.

General principles of anesthesia and sedation in food animals

Minimal-risk anesthesia practice demands that fundamental physiologic and pharmacologic principles be applied to the specific medical and surgical needs of individual patients. In developing an anesthesia plan for a patient, health status must be assessed and considered along with other extrinsic factors such as the physical setting in which the anesthetic procedure will be performed, the availability of equipment and supplies, and the academic and technical training and abilities of participating personnel. This article reviews considerations for developing anesthesia protocols for ruminant and swine species.

Genetic heterogeneity of familial primary cutaneous amyloidosis: lack of evidence for linkage with the chromosome 10 pericentromeric region in Chinese families

Primary cutaneous amyloidosis is a relatively common skin disease in Southeast Asia, South America, and the Republic of China. Although most cases are sporadic, some patients have a family history, suggesting that genetic factors may play a role in its pathogenesis. Some patients with multiple endocrine neoplasia type 2A also have a clinical picture of primary cutaneous amyloidosis. It is thus suggested that the gene of familial primary cutaneous amyloidosis is linked to the pericentromeric region of chromosome 10, the location of the RET proto-oncogene. We have carried out linkage analysis in seven families with cutaneous amyloidosis using four dinucleotide repeat markers from the RET region. Negative lod scores at all recombination frequencies were obtained. We thus conclude that there is no evidence for linkage between Chinese families with primary cutaneous amyloidosis and the pericentromeric region of chromosome 10. The distinct genetic basis, plus their apparent phenotypic differences in sex ratio, age of onset, and sites of cutaneous lesions, suggests that familial primary cutaneous amyloidosis includes clinical subtypes attributable to genetic heterogeneity.

Systemic amyloidosis with initial polyneuropathy

We report a case of systemic amyloidosis with the initial sign of polyneuropathy. The patient eventually developed heart failure, macroglossia, and ecchymoses 6 years later. Biopsies from the sural nerve and normal-looking skin both proved the existence of amyloid.

Increased blood pressure and neural tone in the silent ischemia of hypertension: disparate effects of immediate release nifedipine

OBJECTIVES

The aims of this study were 1) to evaluate the role of blood pressure and associated neural tonicity in ambient ischemia of a group of hypertensive patients with stable angina, and 2) to determine the efficacy of immediate release nifedipine therapy in controlling the total ischemic burden in both office-measured and ambulatory blood pressure.

BACKGROUND

Low heart rate ischemia, as detected by Holter ambulatory electrocardiographic monitoring, suggests that reduced coronary flow is the major factor leading to ischemia. We previously found that 91% of the ischemic episodes in our hypertensive patients with stable angina were silent.

METHODS

We measured plasma norepinephrine content during ischemic events from blood obtained from automatic pump withdrawal with the assistance of a real-time ST segment depression monitor. We then related the norepinephrine content to ischemic episodes assessed by 48-h Holter recording, blood pressure reading by ambulatory blood pressure monitoring and patients' diaries. Measurements were taken during the placebo period and immediate-release nifedipine therapy in 30 hypertensive patients (20 with and 10 without stable angina).

RESULTS

More than half of the patients had ischemic episodes; 95% of these were silent. Ischemic episodes peaked in the early morning, and 55% occurred during routine sedentary activities. There was a 10% to 15% increase in heart rate at the onset of ischemia associated with a 30% higher plasma norepinephrine level. Seventy-five percent of patients had increased norepinephrine after nifedipine therapy. Nifedipine therapy controlled measured blood pressure but not 24-h ambulatory blood pressure. Ischemic episodes were reduced only in patients whose ambulatory blood pressure was controlled.

CONCLUSIONS

The results suggest that increased neural tone at the time of the ischemic event may play a role in reducing coronary perfusion leading to silent ischemia. Nifedipine therapy (immediate release) was effective in control of ischemia only when both ambulatory and office-measured blood pressure were controlled.

KONCPA: a new method for diagnosing tinea unguium

Tinea unguium (TU) is very common in tropical and subtropical regions. An inexpensive, quick and sensitive test is essential for screening the nail specimens. We investigated if a test using potassium hydroxide (KOH)-treated nail clippings, which were then crushed and stained with periodic acid-Schiff (PAS), could be useful for diagnosing TU. The new method (abbreviated as KONCPA) was proved to be more fruitful to identify fungal hyphae in comparison with conventional KOH nail scraping preparation, histopathologic examination and fungal culture. The positive rates of each method were 77, 44, 60 and 16%, respectively. All 10 KONCPA-negative nails failed to show fungus by the other three methods. The KONCPA slides can be permanently stored as records. In addition, we also found that treatment of nail specimens in 20% KOH at 56 degrees C for 10 min prior to histopathologic processing is a simple method to soften the nail plate.