Recurrence of Classic Scabies in a Patient Who had Unchanged Tie String of the T-Cannula

A 64-year old woman who underwent lung transplantation and had t-cannula contracted classic scabies from her daughter. The patient was treated with 5% permethrin 10 times and had two consecutive negative follow-up microscopic examinations. However, the patient had recurrent symptoms and diagnosed with recurrent classic scabies 22 days after the last treatment. Unchanged tie string and unapplied topical agent around the t-cannula skin lesion may be reasons for recurrence. Thus, accurate application of topical treatment and changing the tie string of the t-cannula is needed to prevent a recurrence.

Clustering and multiple-spreading events of nosocomial severe acute respiratory syndrome coronavirus 2 infection

Background

There is growing evidence that super-spreading events (SSEs) and multiple-spreading events (MSEs) are a characteristic feature of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. However, data regarding the possibility of SSEs or MSEs in healthcare settings are limited.

Methods

This study was performed at a tertiary-care hospital in Korea. We analysed the nosocomial COVID-19 cases that occurred in healthcare workers and inpatients and their caregivers between January and 20^th December 2020. Cases with two to four secondary cases were defined as MSEs and those with five or more secondary cases as SSEs.

Findings

We identified 21 nosocomial events (single-case events, N = 12 (57%); MSE + SSE, N = 9 (43%)) involving 65 individuals with COVID-19. Of these 65 individuals, 21 (32%) were infectors. The infectors tended to have a longer duration between symptom onset and diagnostic confirmation than did the non-infectors (median two days vs zero days, P=0.08). Importantly, 12 (18%) individuals were responsible for MSEs and one (2%) for an SSE, which collectively generated 35 (54%) secondary cases.

Conclusion

In a hospital with thorough infection-control measures, approximately 70% of the nosocomial cases of COVID-19 did not generate secondary cases, and one-fifth of the infectors were responsible for SSEs and MSEs, which accounted for approximately half of the total cases. Early case identification, isolation, and extensive contact tracing are important for the prevention of transmission and SSEs.

Nosocomial Outbreak of COVID-19 in a Hematologic Ward

Background

Coronavirus disease 2019 (COVID-19) outbreaks occur in hospitals in many parts of the world. In hospital settings, the possibility of airborne transmission needs to be investigated thoroughly.

Materials and Methods

There was a nosocomial outbreak of COVID-19 in a hematologic ward in a tertiary hospital, Seoul, Korea. We found 11 patients and guardians with COVID-19 through vigorous contact tracing and closed-circuit television monitoring. We found one patient who probably had acquired COVID-19 through airborne-transmission. We performed airflow investigation with simulation software, whole-genome sequencing of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Results

Of the nine individuals with COVID-19 who had been in the hematologic ward, six stayed in one multi-patient room (Room 36), and other three stayed in different rooms (Room 1, 34, 35). Guardian in room 35 was close contact to cases in room 36, and patient in room 34 used the shared bathroom for teeth brushing 40 minutes after index used. Airflow simulation revealed that air was spread from the bathroom to the adjacent room 1 while patient in room 1 did not used the shared bathroom. Airflow was associated with poor ventilation in shared bathroom due to dysfunctioning air-exhaust, grill on the door of shared bathroom and the unintended negative pressure of adjacent room.

Conclusion

Transmission of SARS-CoV-2 in the hematologic ward occurred rapidly in the multi-patient room and shared bathroom settings. In addition, there was a case of possible airborne transmission due to unexpected airflow.

Importance of Follow-Up Microscopic Examination in Hospitalized Patients with Confirmed Scabies

We investigated the duration of positive microscopic examination in hospitalized patients with confirmed scabies in an acute care hospital. We included hospitalized patients who were diagnosed with scabies between January 2015 and June 2019. From the study period, a total of 31 patients with confirmed scabies were identified. Median age was 75 years. Of a total of 31 patients with confirmed scabies, six were discharged or transferred before getting a negative microscopic test result. Of the remaining 25 patients with negative microscopic test results, the median duration from diagnosis to a negative microscopic test result was 14 days (interquartile range, 9-17). Given that nosocomial outbreaks lead to high workload and considerable resource consumption, adequate treatment, sufficient follow-up examination, and confirmation of cure are warranted before releasing contact isolation.

Candida auris colonization or infection of the ear: A single-center study in South Korea from 2016 to 2018

Candida auris was first identified in Japan from specimens obtained from the ear, but most reports since have reported invasive infections or non-ear based cases. We reviewed all the microbiology records from a single center in South Korea from February 2016 to July 2018. One hundred eleven isolates were positive for C. auris from 79 patients. All 79 patients positive for C. auris had positive ear discharge samples. All but one of the patients with C. auris had been to the otorhinolaryngology clinic. Symptom-driven ear culture was done for all but one patient, whose culture was performed for surveillance. Ear discharges were mostly purulent (60%) or serous (34%). We performed the environmental cultures at the otorhinolaryngology outpatient clinic to evaluate the environmental contamination of C. auris, but C. auris was not isolated from medical equipment and environmental surfaces.

Isosamidin from Peucedanum japonicum Roots Prevents Methylglyoxal-Induced Glucotoxicity in Human Umbilical Vein Endothelial Cells via Suppression of ROS-Mediated Bax/Bcl-2

Methylglyoxal (MGO) is a highly reactive metabolite of glucose. Elevated levels of MGO induce the generation of reactive oxygen species (ROS) and cause cell death in endothelial cells. Vascular endothelial cell damage by ROS has been implicated in the progression of diabetic vascular complications, cardiovascular diseases, and atherosclerosis. In this study, the protective effect of isosamidin, isolated from Peucedanum japonicum roots, on MGO-induced apoptosis was investigated using human umbilical vein endothelial cells (HUVECs). Among the 20 compounds isolated from P. japonicum, isosamidin showed the highest effectiveness in inhibiting MGO-induced apoptosis of HUVECs. Pretreatment of HUVECs with isosamidin significantly prevented the generation of ROS and cell death induced by MGO. Isosamidin prevented MGO-induced apoptosis in HUVECs by downregulating the expression of Bax and upregulating the expression of Bcl-2. MGO treatment activated mitogen-activated protein kinases (MAPKs), such as p38, c-Jun N terminal kinase (JNK), and extracellular signal-regulated kinase (ERK). In contrast, pretreatment with isosamidin strongly inhibited the activation of p38 and JNK. Furthermore, isosamidin caused the breakdown of the crosslinks of the MGO-derived advanced glycation end products (AGEs). These findings suggest that isosamidin from P. japonicum may be used as a preventive agent against MGO-mediated endothelial dysfunction in diabetes. However, further study of the therapeutic potential of isosamidin on endothelial dysfunction needs to explored in vivo models.

The Rate of Acquisition of Carbapenemase-Producing Enterobacteriaceae among Close Contact Patients Depending on Carbapenemase Enzymes

Background

Carbapenemase-producing Enterobacteriaceae (CPE) are highly drug-resistant pathogens. Screening the contacts of newly-identified CPE patients is crucial for nosocomial transmission control. We evaluated the acquisition rate of CPE in close contacts as a function of CPE genotype.

Materials and Methods

This study was conducted in Asan Medical Center, a 2,700-bed, tertiary teaching hospital in Seoul, Korea, between November 2010 and October 2017. Index cases were defined as patients with positive tests for CPE from any infected or colonized site during hospitalization who had no direct epidemiologic linkage with existing CPE patients; close contact patients were defined as those whose hospital stay overlapped with the stay of an index case for at least one day and who occupied the same room or intensive care unit (ICU). Secondary patients were defined as those who produced positive CPE culture isolates from surveillance cultures that had the same CPE enzyme as that of the index case patients.

Results

A total of 211 index case patients and 2,689 corresponding contact patients were identified. Of the contact patients, 1,369 (50.9%) including 649 New-Delhi metallo-beta-lactamase-1 (NDM-1) and 448 Klebsiella pneumoniae carbapenemase (KPC)-producing CPE exposures were screened, and 44 secondary patients (3.2%; 95% confidence interval 2.3 - 4.3%) were positive for NDM-1-producing CPE (16 patients) and KPC-producing (24 patients) CPE. The CPE acquisition rate (5.4%) for KPC-producing CPE exposures was significantly higher than that for NDM-1 exposures (2.7%) (P = 0.01).

Conclusion

The CPE acquisition rate was 3.2% among close contacts sharing a multi-patient room, with about a two-fold higher risk of KPC-producing CPE than NDM-1-producing CPE.

Seroprevalence of mumps in healthcare workers in South Korea

Mumps is contagious disease and maintaining immunity to mumps in healthcare worker (HCW) is important for preventing transmission in the hospital. We evaluated the seroprevalence of mumps in HCWs in a tertiary care hospital in Republic of Korea. A total of 6,055 HCWs born between 1950 and 1995 underwent antibody testing. The overall seropositivity rate of mumps was 87% (95% confidence interval, 86%-87%). Our data indicates that, in Korean HCWs, testing for mumps antibody followed by mumps vaccination is more appropriate than routine mumps vaccination without testing for mumps antibody.

2455. Outbreak of carbapenemase-producing Enterobacteriaceae in cardiology units associated with contaminated water dispenser and sink drain in Korea

Background

There is a growing concern about the importance of hospital water environment for the transmission of carbapenemase-producing Enterobacteriaceae (CPE). Herein, we report a large outbreak in cardiology units involving intensive care units (ICU) and wards at a tertiary care hospital.

Methods

During a CPE outbreak between July and December 2018, contact tracing and environmental sampling were performed. For outbreak control, we performed education to healthcare workers, hand hygiene enforcement, active surveillance test, preemptive isolation, chlorhexidine bathing for CPE positive patients, and deep terminal cleaning including UV and hydrogen peroxide non-touch disinfection. Patients with CPE were isolated at a single room with dedicated staffs, contact precaution was implemented, and when case patients were located in multi-patient room, we performed surveillance culture for exposed patients in the room.

Results

A total of 87 patients with CPE infection or colonization were identified at two cardiology ICUs and three cardiology wards. CPE from the first two index patients were identified from sputum culture suspecting pneumonia, and the remaining 85 patients were identified to harbor CPE through surveillance culture (exposed patients n = 22, active surveillance test n = 63). Diverse organisms were identified; organisms with blakpc (n = 13), blaNDM-1 (n = 55), blaVIM or blaIMP (n = 12), blaOXA-48 (n = 3), and co-producing organisms (n = 4). We performed environmental culture; KPC-producing Escherichia coli was isolated from water dispenser in ICU and NDM-1 producing Citrobacter freundii and Enterobacter cloacae were isolated from sinks in the patient room. Outbreak ended after the removal of water dispenser and the replacement of sink drain with pouring bleach to the sink drain.

Conclusion

Water dispenser and sink drain were suspected for the possible reservoirs of CPE in this outbreak. Replacement of plumbing system and use of bleach for pouring to sink as well as the removal of water dispenser was needed to control outbreak. Investigation of water system is warranted for finding the source of CPE.

Disclosures

All authors: No reported disclosures.

Seroprevalence of Measles in Healthcare Workers in South Korea

There are only limited data regarding the seroprevalence of measles of healthcare workers (HCWs) in Korea. We evaluated the seroprevalence of measles in HCWs in a tertiary care hospital in Korea. A total of 7,411 HCWs born from 1952 to 1995 underwent antibody test. The overall seropositivity of measles was 73% (95% confidence interval, 72 – 74). The seropositivity of measles sharply declined from 85% in the 1986 birth cohort to 42% in the 1995 birth cohort, thus signifying pockets of under-immunity. Our data warrant the need for routine antibody tests, followed by measles vaccination or routine measles vaccination in young Korean HCWs.

Determination of the Absolute Configuration of Khellactone Esters from Peucedanum japonicum Roots

Sixteen new angular dihydropyranocoumarins (1-16) and 24 known compounds were isolated from the roots of Peucedanum japonicum Thunb. The absolute configuration of diacylkhellactone was established by partial hydrolysis, the Mosher method, and X-ray crystallography. In addition, ECD spectroscopy was used to assign the absolute configurations of several of the angular dihydropyranocoumarins. Enantiomers were detected by RP-HPLC using MTPA esters while acyl migration of the substituents was observed in cis-monoacylkhellactones.

Spinal Accessory Nerve: Ultrasound Findings and Correlations with Neck Lymph Node Levels

Purpose: To evaluate the ultrasound characteristics of the spinal accessory nerve (SAN) and correlate nerve location with neck lymph node level. Materials and Methods: 50 participants with 100 SANs were enrolled in this study. The SAN was traced from the trapezius muscle to the upper neck and was identified by a hypoechoic linear structure without color Doppler flow. The ultrasound characteristics of the SAN, such as visibility, diameter, relationship with adjacent structures, and its correlation with lymph node levels, were evaluated. Results: The SAN was identified in 96 %-100 % of segments. The mean diameter of the SAN was 0.54 ± 0.09 mm. The SANs was located between the trapezius and levator scapulae muscles and 90.8 % were traced into the trapezius muscle. In the upper neck, the SAN passed deep into the sternocleidomastoid (SCM) muscle in 38 % of cases and between the two heads of the SCM muscle in 62 % of cases. The SAN was found at neck lymph node levels II, III, IV, and V, but not I or VI. Conclusion: Continuous ultrasound monitoring of the SAN and its correlation with lymph node levels is possible in most patients. Our current findings may assist in the future prevention of SAN injury during ultrasound-guided procedures.

A prospective study on symptom generation according to spicy food intake and TRPV1 genotypes in functional dyspepsia patients

BACKGROUND

Capsaicin is an ingredient of red peppers that binds to transient receptor potential vanilloid subtype 1 (TRPV1), and Koreans eat more capsaicin-rich food than do Japanese. This study aimed to compare symptom generation according to TRPV1 genotypes and the intake of spicy foods.

METHODS

Consecutive functional dyspepsia (FD) patients who were evaluated at Konkuk University Medical Centre (Korea) and Keio University Hospital (Japan) were included. Questionnaires on spicy food intake, patient assessment of gastrointestinal symptoms (PAGI-SYM), patient assessment of quality of life, and hospital anxiety and depression scale were provided. Blood was sampled for the detection of TRPV1 polymorphisms, and upper gastrointestinal endoscopy was performed with biopsies.

KEY RESULTS

Of 121 included subjects, 35 and 28 carried the TRPV1 CC and GG genotypes, respectively, with the prevalence rates not differing between Japan and Korea. The prevalence of FD subtypes did not differ with the spicy food intake, TRPV1 genotypes, or Helicobacter pylori infection. Neither TRPV1 polymorphisms nor H. pylori infections were related to scores on the PAGI-SYM questionnaires, but spicy food intake was positively correlated with the scores for stomach fullness (p = 0.001) and retching (p = 0.001). Using the linear regression analysis, stomach fullness was associated with spicy food intake (p = 0.007), whereas retching was related to younger age (p < 0.001) and female gender (p = 0.014).

CONCLUSIONS & INFERENCES

Upper gastrointestinal symptoms are more common in subjects with a higher consumption of spicy foods, younger age and female gender, regardless of TRPV1 genotypes and the H. pylori infection status. Capsaicin-rich foods may induce stomach fullness.

Stereoisomer-specific anticancer activities of ginsenoside Rg3 and Rh2 in HepG2 cells: disparity in cytotoxicity and autophagy-inducing effects due to 20(S)-epimers

Autophagy has been an emerging field in the treatment of hepatic carcinoma since anticancer therapies were shown to ignite autophagy in vitro and in vivo. Here we report that ginsenoside Rg3 and Rh2, major components of red ginseng, induce apoptotic cell death in a stereoisomer-specific fashion. The 20(S)-forms of Rg3 and Rh2, but not their respective 20(R)-forms, promoted cell death in a dose-dependent manner accompanied by downregulation of Bcl2 and upregulation of Fas, resulting in apoptosis of HepG2 cells with poly ADP ribose polymerase cleavage. The LD50 value [45 µM for Rg3(S), less than 10 µM for Rh2(S)] and gross morphological electron microscopic observation revealed more severe cellular damage in cells treated with Rh2(S) than in those treated with Rg3(S). Both Rg3(S) and Rh2(S) also induced autophagy when undergoing induced apoptosis. Inhibition of autophagy with lysosomotrophic agents significantly potentiated the cellular damage, implying a favorable switch of the cell fate to tumor cell death. Blocking intracellular calcium with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis(acetoxymethyl ester) (BAPTA-AM) restored the cell death induced by both Rg3(S) and Rh2(S). Our results suggest that the 20(S)-forms of Rg3 and Rh2 in red ginseng possess more potent antitumor activity with autophagy than their 20(R)-forms via calcium-dependent apoptosis.

A genetic variation in microRNA target site of KRT81 gene is associated with survival in early-stage non-small-cell lung cancer

BACKGROUND

MicroRNAs (miRNAs) have a key role in carcinogenesis through negative regulation of their target genes. Therefore, genetic variations in miRNAs or their target sites may affect miRNA-mRNA interactions, thereby result in altered expression of target genes. This study was conducted to investigate the associations between single-nucleotide polymorphisms (SNP) located in the miRNA target sites (poly-miRTSs) and survival of patients with early-stage non-small-cell lung cancer (NSCLC).

METHODS

Using public SNP database and miRNA target sites prediction program, 354 poly-miRTSs were selected for genotyping. Among these, 154 SNPs applicable to Sequenom's MassARRAY platform were investigated in 357 patients. A replication study was carried out on an independent patient population (n = 479). Renilla luciferase assay and reverse transcription-polymerase chain reaction were conducted to examine functional relevance of potentially functional poly-miRTSs.

RESULTS

Of the 154 SNPs analyzed in a discovery set, 14 SNPs were significantly associated with survival outcomes. Among these, KRT81 rs3660G>C was found to be associated with survival outcomes in the validation cohort. In the combined analysis, patients with the rs3660 GC + CC genotype had a significantly better overall survival compared with those with GG genotype [adjusted hazard ratio (aHR) for OS, 0.65; 95% confidence interval (CI) 0.50-0.85; P = 0.001]. An increased expression of the reporter gene for the C allele of rs3660 compared with the G allele was observed by luciferase assay. Consistently, the C allele was associated with higher relative expression level of KRT81 in tumor tissues.

CONCLUSION

The rs3660G>C affects KRT81 expression and thus influences survival in early-stage NSCLC. The analysis of the rs3660G>C polymorphism may be useful to identify patients at high risk of a poor disease outcome.

Comparison of the clinical characteristics and imaging findings of acute cholangitis with and without biliary dilatation

OBJECTIVE

To evaluate the causes of acute cholangitis without biliary dilatation and to compare the clinical characteristics and the imaging findings between patients with acute cholangitis with and without biliary dilatation.

METHODS

93 patients diagnosed with acute cholangitis underwent contrast-enhanced CT. Among them, 17 patients were classified as not having biliary dilatation (Group 1) and 76 patients were classified as having biliary dilatation (Group 2). The causes of acute cholangitis were evaluated in both groups. Clinical characteristics and imaging findings were compared between the two groups.

RESULTS

The causes of acute cholangitis without biliary dilatation included common bile duct (CBD) stones (n=11), CBD sludge (n=3), a passed stone (n=1) and unknown causes (n=2). The total bilirubin levels of Group 1 were significantly lower than those of Group 2 (p=0.001). By contrast, Group 1 had higher median alanine aminotransferase (ALT) levels than Group 2 (p=0.04). The length of hospital stay was significantly longer in Group 2 than in Group 1 patients (p<0.001). In the imaging findings, the extent of transient hepatic attenuation differences (THADs) (p=0.003) were significantly smaller in Group 1 than in Group 2.

CONCLUSION

CBD stones and sludge were the most common causes of acute cholangitis in patients without biliary dilatation. These patients showed lower levels of bilirubin and higher levels of ALT than those with acute cholangitis with biliary dilatation, and had a shorter duration of hospital stay. The extent of THADs was the only discriminative CT finding between the two groups.

ADVANCES IN KNOWLEDGE

Acute cholangitis can present without biliary dilatation on imaging, and the most common causes are CBD stones and sludge. The patients with acute cholangitis without biliary dilatation have different clinical characteristics and imaging findings compared with those with acute cholangitis presenting with biliary dilatation.

Diagnostic performance of multidetector CT for acute cholangitis: evaluation of a CT scoring method

OBJECTIVE

The aim of this study was to retrospectively assess the diagnostic performance of multidetector CT (MDCT) for the diagnosis of acute cholangitis using a new scoring method.

METHODS

Of 80 patients with suspected biliary disease who underwent biphasic CT and endoscopic retrograde cholangiography, 39 were diagnosed as having acute cholangitis (Group 1) and 41 patients were classified as suspected biliary disease (Group 2). 100 age-matched patients without evidence of biliary disease were selected randomly as a control group (Group 3). Each patient's axial scan was scored by two independent radiologists for the extent of transient hepatic attenuation difference, the presence of biliary dilatation and identification of a biliary obstructive lesion. The difference in the scores among the three groups was evaluated and the optimal cut-off score for the diagnosis of acute cholangitis was determined. Interobserver agreement was also evaluated.

RESULTS

The total scores (mean ± standard deviation) for Groups 1, 2 and 3 were 7.0 ± 2.0, 4.4 ± 2.4 and 0.9 ± 1.2, respectively, for Reviewer 1 and 7.2 ± 2.7 and 0.7 ± 1.1, respectively, for Reviewer 2. Significant differences were found for the subscores and the total scores among the three groups (p < 0.001). Using a cut-off score of ≥ 5, the sensitivity and specificity for diagnosing acute cholangitis were 84.6% and 83.7%, respectively, for Reviewer 1 and 89.7% and 83.7%, respectively, for Reviewer 2. Agreement for the subscores between readers was good to excellent (κ = 0.74-0.86).

CONCLUSION

Based on dynamic MDCT and the described CT scoring method, the diagnosis of acute choangitis can be made with high sensitivity and specificity.

Food insecurity is associated with dietary intake and body size of Korean children from low-income families in urban areas

OBJECTIVE

This study examined household food insecurity of urban low-income families in Korea and the associations of the food insecurity with children's dietary intake and body size.

DESIGN

Cross-sectional study.

SETTING

Low-income neighborhoods in large cities.

SUBJECTS

Included 370 children aged 4-12 y, who had all records on dietary intake and anthropometry as well as household food insecurity measures.

RESULTS

Using the 10-item Radimer/Cornell Scale, 62.7% of the households showed some degree of food insecurity (8.6% for food insecure for family, 28.4% for food insecure for adults and 25.7% for child hunger households). Food insecurity was linearly and negatively associated with household economic conditions as well as the caretaker's use of nutrition knowledge. There were also significant associations of food insecurity with the children's dietary intakes, indicating the largest amount of nutrients for the children from the household food insecure, followed by those from the food secure, adult food insecure and child hunger groups. The household food insecure children were fatter than the food secure children. The fatter condition of the former children appeared to be related to more frequent intakes of low-quality foods.

CONCLUSION

This study reports curvilinear associations between the status of household food insecurity and children's food intakes and fatness.

SPONSORSHIP

This work was funded by a grant of the 2001 Korea Health Promotion Research Program, the Ministry of Health & Welfare, Republic of Korea.

Relationship between dobutamine echocardiography and the elevation of cardiac troponin I in patients with acute coronary syndromes

An elevated cardiac troponin I (cTnI) and a positive dobutamine echocardiography are powerful predictors for future cardiac events in patients with coronary artery disease. Investigating their correlation also should be helpful in understanding their clinical usefulness in evaluating patients with acute coronary syndromes (ACS). Dobutamine echocardiography and a blood sampling for cTnI were performed on 117 patients with ACS 70 +/- 2 hours after arriving at the hospital. CTnI was considered elevated when its value was greater than 2.0 ng/ml. Dobutamine echocardiography was positive in 86 (73.5%) patients, and cTnI was elevated in 37 (31.6%). The occurrence of positive dobutamine echocardiography in patients with elevated cTnI was significantly higher than in those with normal cTnI (86.5% vs. 67.5%, P = 0.042). More patients in the elevated cTnI group developed myocardial ischemia before or at the stage of dobutamine 20 microg/kg/min (43.2% vs. 15%, P = 0.002). When compared with patients with normal cTnI, patients with elevated cTnI had a lower ischemic threshold during dobutamine echocardiography, and more frequently had baseline echocardiographic wall-motion abnormalities, a history of myocardial infarction, and a positive dobutamine echocardiography. Using multivariate analysis, we found that only a lower dobutamine echocardiography ischemic threshold (P = 0.0008) and baseline wall-motion abnormalities (P = 0.0004) were associated independently with the elevation of cTnI. Our results suggest that in patients with ACS, dobutamine echocardiography can offer information regarding wall-motion abnormalities and ischemic threshold, which are suggested to have a clinical value similar to elevated cTnI.

Aberrant development of thymocytes in mice lacking laminin-2

In previous in vitro studies, we proposed a role for the extracellular matrix component, laminin-2, and its integrin receptor, VLA-6, in thymocyte development. The characterization of two dystrophic mouse strains with different defects in laminin-2 allowed us to examine this proposal in vivo. Mice deficient in laminin-2, dy/dy, show a significant reduction in thymus size and number of thymocytes compared to normal littermates. These mice also exhibited apparent alterations of thymic architecture. Examination of the CD4/CD8 populations in dy/dy thymi showed large relative increases in the DN (CD4- CD8-) and SP (CD4+ CD8-, CD4- CD8+) populations and a significant decrease in the DP (CD4+ CD8+) population. Further examination of the DN population for CD44 and CD25 expression showed a remarkable decrease in the more mature pre-T cell populations. Analysis of apoptosis in situ, and by flow cytometry, in dy/dy thymi revealed a significant increase in apoptotic DN thymocytes in the capsule and subcapsular regions. Interestingly, thymocyte development appeared to proceed normally in dystrophic mice expressing a mutant form of laminin-2, dy2J, as well as, in fetal and neonatal dy/dy mice. We propose that laminin-2 plays an active role in thymocyte development by delivering cell survival and differentiation signals at specific stages of development in young adult mice.

Expression of a novel integrin beta 1 chain epitope and anti-beta 1 antibody-mediated enhancement of fibronectin binding are dependent on the stage of T cell differentiation

Beta 1 integrins are a family of alpha beta heterodimers that serve as cell surface receptors for extracellular matrix proteins. We demonstrate that the anti-mouse integrin beta 1 chain mAb KMI6 selectively recognizes a beta 1 epitope that is constitutively expressed by certain immature thymocytes and is induced only slightly on mature thymocytes and peripheral T cells by activation with Con A. Because virtually all cells examined expressed beta 1 integrins on their surface, expression of the KMI6 epitope is T cell differentiation stage specific. Most CD3-4-8- thymocytes were KMI6+, with the lowest level of staining observed on the earliest CD44+IL-2R- cells within this subset. Expression was down-regulated during the CD3-4-8- to CD3-4-8+ transition, and lost by the CD4+8+ stage. Mature single positive thymocytes and resting peripheral T cells were also KMI6-. In contrast with the loss of the epitope before TCR expression by other thymocytes, most CD3+4-8- and certain CD8+ gamma delta TCR+ thymocytes were KMI6+ Addition of KMI6 to cell adhesion assays enhanced CD4-8- thymocyte, but not activated mature thymocyte or peripheral T cell, binding to fibronectin (via alpha 4 beta 1 and alpha 5 beta 1), whereas laminin binding (via alpha 6 beta 1) was unaffected. These properties distinguish the KMI6 epitope from other epitopes involved in beta 1 integrin activation in mice and other species. The unique selectivity of KMI6 recognition of beta 1 integrins, and its selective enhancement of ligand binding suggest that beta 1 integrin structure and factors that regulate beta 1 integrin binding are correlated with the stage of T cell differentiation.

Expression of a novel integrin beta 1 chain epitope and anti-beta 1 antibody-mediated enhancement of fibronectin binding are dependent on the stage of T cell differentiation

Beta 1 integrins are a family of alpha beta heterodimers that serve as cell surface receptors for extracellular matrix proteins. We demonstrate that the anti-mouse integrin beta 1 chain mAb KMI6 selectively recognizes a beta 1 epitope that is constitutively expressed by certain immature thymocytes and is induced only slightly on mature thymocytes and peripheral T cells by activation with Con A. Because virtually all cells examined expressed beta 1 integrins on their surface, expression of the KMI6 epitope is T cell differentiation stage specific. Most CD3-4-8- thymocytes were KMI6+, with the lowest level of staining observed on the earliest CD44+IL-2R- cells within this subset. Expression was down-regulated during the CD3-4-8- to CD3-4-8+ transition, and lost by the CD4+8+ stage. Mature single positive thymocytes and resting peripheral T cells were also KMI6-. In contrast with the loss of the epitope before TCR expression by other thymocytes, most CD3+4-8- and certain CD8+ gamma delta TCR+ thymocytes were KMI6+ Addition of KMI6 to cell adhesion assays enhanced CD4-8- thymocyte, but not activated mature thymocyte or peripheral T cell, binding to fibronectin (via alpha 4 beta 1 and alpha 5 beta 1), whereas laminin binding (via alpha 6 beta 1) was unaffected. These properties distinguish the KMI6 epitope from other epitopes involved in beta 1 integrin activation in mice and other species. The unique selectivity of KMI6 recognition of beta 1 integrins, and its selective enhancement of ligand binding suggest that beta 1 integrin structure and factors that regulate beta 1 integrin binding are correlated with the stage of T cell differentiation.

Alpha 3 beta 1 and alpha 6 beta 1 integrins mediate laminin/merosin binding and function as costimulatory molecules for human thymocyte proliferation

Integrins comprise a superfamily of alpha beta heterodimers that serve as cell signaling as well as adhesion molecules. We demonstrate that the alpha 3 beta 1 and alpha 6 beta 1 integrins are laminin/merosin receptors expressed in human thymocytes. By reverse transcriptase-PCR analysis, we determined that the alpha 3A beta 1, but not the alpha 3B beta 1, cytoplasmic structural variant of alpha 3 beta 1 is expressed in thymocytes. In contrast, both alpha 6A beta 1 and alpha 6B beta 1 cytoplasmic structural variants of alpha 6 beta 1 are expressed. A small percentage (10 to 15%) of human thymocytes bind to immobilized laminin, and even fewer (3 to 5%) bind to merosin, the laminin isoform normally present in the thymus. This binding, however, can be increased to 39 to 41% after activation of thymocytes with Mn2+ (or PMA). Binding to either laminin or merosin is completely inhibited by anti-beta 1 mAb or by a mixture of anti-alpha 3 and anti-alpha 6 mAbs, indicating that both alpha 3 beta 1 and alpha 6 beta 1 participate in thymocyte adhesion to the laminin family of extracellular matrix proteins. The protein kinase C inhibitors, calphostin C and staurosporine, inhibit Mn(2+)-enhanced thymocyte binding, suggesting that protein kinase C activity is crucial for the binding. Furthermore, the data indicate that at least two divalent cation binding sites serve to regulate integrin binding activity. Finally, we show that both immobilized laminin and merosin have costimulatory function for anti-CD3-induced thymocyte proliferation, and both anti-alpha 3 and anti-alpha 6 mAbs can block this proliferative response. The cooperative function of alpha 3 beta 1 and alpha 6 beta 1 evidenced in the laminin/merosin binding and proliferation assays suggests that thymocyte-merosin interactions may play an important role in thymic T cell development.

Alpha 3 beta 1 and alpha 6 beta 1 integrins mediate laminin/merosin binding and function as costimulatory molecules for human thymocyte proliferation

Integrins comprise a superfamily of alpha beta heterodimers that serve as cell signaling as well as adhesion molecules. We demonstrate that the alpha 3 beta 1 and alpha 6 beta 1 integrins are laminin/merosin receptors expressed in human thymocytes. By reverse transcriptase-PCR analysis, we determined that the alpha 3A beta 1, but not the alpha 3B beta 1, cytoplasmic structural variant of alpha 3 beta 1 is expressed in thymocytes. In contrast, both alpha 6A beta 1 and alpha 6B beta 1 cytoplasmic structural variants of alpha 6 beta 1 are expressed. A small percentage (10 to 15%) of human thymocytes bind to immobilized laminin, and even fewer (3 to 5%) bind to merosin, the laminin isoform normally present in the thymus. This binding, however, can be increased to 39 to 41% after activation of thymocytes with Mn2+ (or PMA). Binding to either laminin or merosin is completely inhibited by anti-beta 1 mAb or by a mixture of anti-alpha 3 and anti-alpha 6 mAbs, indicating that both alpha 3 beta 1 and alpha 6 beta 1 participate in thymocyte adhesion to the laminin family of extracellular matrix proteins. The protein kinase C inhibitors, calphostin C and staurosporine, inhibit Mn(2+)-enhanced thymocyte binding, suggesting that protein kinase C activity is crucial for the binding. Furthermore, the data indicate that at least two divalent cation binding sites serve to regulate integrin binding activity. Finally, we show that both immobilized laminin and merosin have costimulatory function for anti-CD3-induced thymocyte proliferation, and both anti-alpha 3 and anti-alpha 6 mAbs can block this proliferative response. The cooperative function of alpha 3 beta 1 and alpha 6 beta 1 evidenced in the laminin/merosin binding and proliferation assays suggests that thymocyte-merosin interactions may play an important role in thymic T cell development.

Isolated left coronary ostial stenosis--a case report

A patient with isolated left coronary ostial stenosis proved by coronary angiography is presented. Isolated left coronary ostial stenosis is a rare condition of unknown etiology. Unique clinical and angiographic profiles are discussed in detail with a review of the literature, along with a suggestion of a natural history distinct from that usually seen in atherosclerotic coronary diseases.