Five undescribed aryltetralin lignans with cytotoxic activities from the fruits of Cleistanthus eberhardtii

Five undescribed lignans, cleiseberharnins A-D (1-4), cleiseberharside A (5) were isolated from the fruits of Cleistanthus eberhartii (Phyllanthaceae), together with six known aryltetralin lignans, cleistantoxin (6), picroburseranin (7), neocleistantoxin (8), 7-hydroxypicropolygamain (9), cleisindoside D (10), and cleisindoside A (11). Their structures and relative configurations were established by analysis of HRESIMS and NMR data, and quantum chemical calculations of JH,H coupling constants. The absolute configurations of 1-5 were determined by analysis of their experimental CD spectra and comparison with calculated electronic circular dichroism (ECD) spectra. All compounds (1-11) were evaluated for their cytotoxicity against KB, MCF-7, HepG-2, and Lu-1 human cancer cell lines. Among the tested compounds, compounds 6 and 7 showed strong activity against KB, MCF7, HepG2 and Lu-1 cell lines with IC50 values in the range of 0.02-0.62 μM. Compound 1 showed activity against three cancer cell lines KB, HepG2, and Lu-1 with IC50 values of 6.98, 7.61 and 11.75 μM, respectively. Compound 2 exhibited a selective inhibition with moderate cytotoxicity against Lu-1 with IC50 value of 15.30 μM. Compounds 4, 5 and 9 showed moderate activity against the three cancer cell lines with IC50 values in the range of 8.73-19.70 μM.

Optimal symptom combinations to aid COVID-19 case identification: Analysis from a community-based, prospective, observational cohort

Objectives

Diagnostic work-up following any COVID-19 associated symptom will lead to extensive testing, potentially overwhelming laboratory capacity whilst primarily yielding negative results. We aimed to identify optimal symptom combinations to capture most cases using fewer tests with implications for COVID-19 vaccine developers across different resource settings and public health.

Methods

UK and US users of the COVID-19 Symptom Study app who reported new-onset symptoms and an RT-PCR test within seven days of symptom onset were included. Sensitivity, specificity, and number of RT-PCR tests needed to identify one case (test per case [TPC]) were calculated for different symptom combinations. A multi-objective evolutionary algorithm was applied to generate combinations with optimal trade-offs between sensitivity and specificity.

Findings

UK and US cohorts included 122,305 (1,202 positives) and 3,162 (79 positive) individuals. Within three days of symptom onset, the COVID-19 specific symptom combination (cough, dyspnoea, fever, anosmia/ageusia) identified 69% of cases requiring 47 TPC. The combination with highest sensitivity (fatigue, anosmia/ageusia, cough, diarrhoea, headache, sore throat) identified 96% cases requiring 96 TPC.

Interpretation

We confirmed the significance of COVID-19 specific symptoms for triggering RT-PCR and identified additional symptom combinations with optimal trade-offs between sensitivity and specificity that maximize case capture given different resource settings.

Optimal symptom combinations to aid COVID-19 case identification: analysis from a community-based, prospective, observational cohort

OBJECTIVES

Diagnostic work-up following any COVID-19 associated symptom will lead to extensive testing, potentially overwhelming laboratory capacity whilst primarily yielding negative results. We aimed to identify optimal symptom combinations to capture most cases using fewer tests with implications for COVID-19 vaccine developers across different resource settings and public health.

METHODS

UK and US users of the COVID-19 Symptom Study app who reported new-onset symptoms and an RT-PCR test within seven days of symptom onset were included. Sensitivity, specificity, and number of RT-PCR tests needed to identify one case (test per case [TPC]) were calculated for different symptom combinations. A multi-objective evolutionary algorithm was applied to generate combinations with optimal trade-offs between sensitivity and specificity.

FINDINGS

UK and US cohorts included 122,305 (1,202 positives) and 3,162 (79 positive) individuals. Within three days of symptom onset, the COVID-19 specific symptom combination (cough, dyspnoea, fever, anosmia/ageusia) identified 69% of cases requiring 47 TPC. The combination with highest sensitivity (fatigue, anosmia/ageusia, cough, diarrhoea, headache, sore throat) identified 96% cases requiring 96 TPC.

INTERPRETATION

We confirmed the significance of COVID-19 specific symptoms for triggering RT-PCR and identified additional symptom combinations with optimal trade-offs between sensitivity and specificity that maximize case capture given different resource settings.

Allergen sensitisation among chronic respiratory diseases in urban and rural areas of the south of Viet Nam

OBJECTIVE

To evaluate the prevalence of and risk factors for allergen sensitisation among patients with chronic respiratory disease (CRD) in southern Viet Nam.

DESIGN

An environmental questionnaire and skin prick tests for airborne and food allergens were administered to patients with CRD, defined as individuals with respiratory symptoms and lung function defects.

RESULTS

Of 610 CRD patients, 56% had chronic obstructive pulmonary disease and 31% were asthma patients; 80% were males. The most frequent sensitisers were dust mites (Dermatophagoides farinae 22%, Blomia tropicalis 19%, D. pteronyssinus 18%) and cockroach droppings (13%). Among study participants, 37% were from rural settings and 36% from urban areas, whereas 27% had migrated from rural to urban areas. Compared with people from rural areas, being born in an urban area was a risk factor for sensitisation to mites (OR 1.56, 95%CI 1.11-2.20, P < 0.02). In multivariate analysis, place of birth remained a risk factor for mite sensitisation. Compared with the native urban population, the risk of mite sensitisation was not significantly different among patients born in rural areas and those migrating to urban areas.

CONCLUSION

Dust mites and cockroach droppings were the most frequent allergens among people with CRD in the south of Viet Nam. Compared with the urban population, being native to a rural area was protective against mite sensitisation, but this effect ceased to be significant after migration from rural to urban areas.

Systematic review with meta-analysis: rifaximin for the prophylaxis of spontaneous bacterial peritonitis

BACKGROUND

The primary and secondary prevention of spontaneous bacterial peritonitis (SBP) is recommended in high-risk patients with cirrhosis. Several studies evaluating the efficacy of rifaximin for SBP prophylaxis have yielded conflicting results. Rifaximin has the potential advantage of preventing bacterial overgrowth and translocation without the systemic side effects of broad-spectrum antibiotics.

AIM

To evaluate the efficacy of rifaximin in the primary and secondary prevention of SBP.

METHODS

A literature search using five databases was performed to identify studies on the association between rifaximin and SBP. We performed two meta-analyses: (1) rifaximin compared to systemic antibiotics and (2) rifaximin compared to no antibiotics. Random-effect modelling was conducted to determine overall pooled estimates and 95% confidence intervals (CIs).

RESULTS

Five studies with 555 patients (295 rifaximin, 260 systemic antibiotics) compared rifaximin with systemic antibiotics. The pooled odds ratio (OR) for SBP was 0.45 (95% CI 0.16-1.27; P = .13) in patients receiving rifaximin and strengthened on sensitivity analysis (OR 0.38, 95% CI 0.19-0.76, P = .01). In the analysis comparing rifaximin with no antibiotics, there were five studies with 784 patients (186 rifaximin, 598 no antibiotics). The OR for SBP was 0.34 (95% CI 0.11-0.99; P < .05) in patients receiving rifaximin. In subgroup analysis, rifaximin reduced the risk of SBP by 47% compared to no antibiotics for primary prophylaxis and by 74% compared to systemic antibiotics for secondary prophylaxis.

CONCLUSION

Rifaximin may be effective in preventing SBP in patients with cirrhosis and ascites compared to systemically absorbed antibiotics and compared to placebo.

Systematic review with meta-analysis: the proportion of chronic hepatitis B patients with normal alanine transaminase ≤ 40 IU/L and significant hepatic fibrosis

BACKGROUND

Chronic hepatitis B (CHB) may lead to cirrhosis, hepatocellular carcinoma and premature death. Elevated alanine transaminase (ALT) levels ≥ the upper limit of normal (ULN) are a major determinant for initiating anti-viral therapy; however, ALT levels alone may not be predictive of hepatic fibrosis.

AIM

To determine the proportion of CHB patients with ALT ≤ 40 IU/L and liver fibrosis stage ≥ 2. Secondary goals include subgroup analysis by hepatitis B e antigen (HBeAg) status, high hepatitis B virus (HBV) DNA levels, Asian ethnicity, lower ULN of ≤ 30 IU/L (males) and 19 IU/L (females), and advanced age.

METHODS

Studies identified in EMBASE and MEDLINE (1/1990-6/2012) using the search criteria: "Hepatitis B"[Mesh] OR "Hepatitis B virus"[Mesh] OR "Hepatitis B, Chronic"[Mesh])) AND "Alanine Transaminase"[Mesh]) and abstracts containing the term 'hepatitis' from recent major U.S. gastroenterology and liver society meetings were considered.

RESULTS

Among nine studies (N = 830 patients), a significant proportion (20.7%; 95% CI: 16.2-26.0%) of CHB patients with ALT levels ≤ 40 IU/L had significant fibrosis irrespective of HBeAg status, high HBV DNA levels, ethnicity or age, although this proportion may be higher in patients older than 30-40 years old. The corresponding proportion was 27.8% even when the newer ULN of 30 IU/L (males) and 19 IU/L (females) was applied.

CONCLUSIONS

Approximately one fifth of CHB patients with ALT ≤ 40 IU/L may have significant hepatic fibrosis. The approach to such patients should be individualised, as further evaluation and treatment may be appropriate.

Systematic review: Asian patients with chronic hepatitis C infection

BACKGROUND

Chronic hepatitis C (CHC) infection is a risk factor for both the development of end-stage liver disease and hepatocellular carcinoma (HCC). Globally, approximately 170 million people are chronically infected with the hepatitis C virus (HCV), and the majority of these individuals come from the western Pacific and Southeast Asia regions (94.6 million persons combined). CHC is an understudied and underappreciated health problem in many Asian countries and in the US, where Asians represent one of the fastest growing groups of new Americans.

AIM

To perform a systematic review of the current literature on the epidemiology, diagnosis and screening, clinical characteristics and response to anti-viral therapy of Asians with CHC.

METHODS

Using a PubMed search of 'hepatitis C' and 'Asia,' 341 original manuscripts published in peer-reviewed journals were identified, and 99 were selected based on their relevance.

RESULTS

Many Asian CHC patients do not have easily identifiable risk factors and may be underdiagnosed. Rates of HCV infection in Asians on community screening in the US are unexpectedly high, and there is a high prevalence of HCV genotype 6 in Southeast Asia and Southern China. HCV-infected Asians tend to present at older age and may have higher risk of HCC; however, they respond better to anti-viral therapy than non-Asians across all HCV genotypes.

CONCLUSIONS

Given the high HCV endemicity in Asia, lack of identifiable risk factors and favourable treatment response rates in Asians, we advocate the screening for HCV infection of all Asians who come from areas where HCV prevalence is ≥2%.

Prevalence of hepatitis B virus DNA polymerase mutations in treatment-naïve patients with chronic hepatitis B

BACKGROUND

One of the most important factors in treatment failure using nucleos(t)ide analogues in chronic hepatitis B is anti-viral resistance. Primary drug resistance refers to amino acid changes in the hepatitis B virus polymerase/reverse transcriptase (rt) that result in reduced susceptibility to anti-viral agents. Pre-existing drug resistance mutations may occur in untreated patients and may affect their treatment outcomes.

AIM

To determine the prevalence of hepatitis B DNA polymerase mutations in treatment-naïve patients.

METHODS

We used a direct PCR sequencing test to detect DNA polymerase mutations in 472 consecutive treatment-naïve patients at two community gastroenterology clinics in Northern California.

RESULTS

A majority of patients were Asians (>95%), had either genotype B or C (95%) and had no evidence of cirrhosis or liver cancer (94%). Mean age was 45 +/- 13 and mean hepatitis B virus DNA was 5.3 +/- 1.8 log(10) IU/mL. Most patients did not have any detectable mutations (82.4%). Some (16.7%) had mutations of unknown clinical significance (rtV207M/L/I) and only 4 patients had rtA181A/S, rtA194S or M250I.

CONCLUSIONS

No rtM204V/I or rtN236T mutations were observed in our study. Less than 1% of our patients had mutations that can be associated with primary resistance to existing anti-viral therapies for hepatitis B virus.

Promoter recognition and discrimination by EsigmaS RNA polymerase

Although more than 30 Escherichia coli promoters utilize the RNA polymerase holoenzyme containing sigmaS (EsigmaS), and it is known that there is some overlap between the promoters recognized by EsigmaS and by the major E. coli holoenzyme (Esigma70), the sequence elements responsible for promoter recognition by EsigmaS are not well understood. To define the DNA sequences recognized best by EsigmaS in vitro, we started with random DNA and enriched for EsigmaS promoter sequences by multiple cycles of binding and selection. Surprisingly, the sequences selected by EsigmaS contained the known consensus elements (-10 and -35 hexamers) for recognition by Esigma70. Using genetic and biochemical approaches, we show that EsigmaS and Esigma70 do not achieve specificity through 'best fit' to different consensus promoter hexamers, the way that other forms of holoenzyme limit transcription to discrete sets of promoters. Rather, we suggest that EsigmaS-specific promoters have sequences that differ significantly from the consensus in at least one of the recognition hexamers, and that promoter discrimination against Esigma70 is achieved, at least in part, by the two enzymes tolerating different deviations from consensus. DNA recognition by EsigmaS versus Esigma70 thus presents an alternative solution to the problem of promoter selectivity.

The human interferon- and estrogen-regulated ISG20/HEM45 gene product degrades single-stranded RNA and DNA in vitro

The human ISG20/HEM45 gene was identified independently on the basis of its increased level of expression in response to either interferon or estrogen hormone. Notably, the encoded protein is homologous with members of the 3' to 5' exonuclease superfamily that includes RNases T and D, and the proofreading domain of Escherichia coli DNA polymerase I. We provide here direct biochemical evidence that Isg20 acts as a 3' to 5' exonuclease in vitro. This protein displays a pH optimum of approximately 7.0, prefers Mn2+ as a metal cofactor, and degrades RNA at a rate that is approximately 35-fold higher than its rate for single-stranded DNA. Along with RNase L, Isg20 is the second known RNase regulated by interferon. Previous data showed that Isg20 is located in promyelocytic leukemia (PML) nuclear bodies, known sites of hormone-dependent RNA polymerase II transcription and oncogenic DNA viral transcription and replication. The combined data suggest a potential role for Isg20 in degrading viral RNAs as part of the interferon-regulated antiviral response and/or cellular mRNAs as a regulatory component of interferon and estrogen signaling.

Micrometastasis to in-transit lymph nodes from extremity and truncal malignant melanoma

BACKGROUND

The sentinel lymph node (SLN) is the first lymph node in the regional nodal basin to receive metastatic cells. In-transit nodes are found between the primary melanoma site and regional nodal basins. To date, this is one of the first reports on micrometastasis to in-transit nodes.

METHODS

Retrospective database and medical records were reviewed from October 21, 1993, to November 19. 1999. At the UCSF Melanoma Center, patients with tumor thickness > 1 mm or < 1 mm with high-risk features are managed with preoperative lymphoscintigraphy, selective SLN dissection, and wide local excision.

RESULTS

Thirty (5%) out of 557 extremity and truncal melanoma patients had in-transit SLNs. Three patients had positive in-transit SLNs and negative SLNs in the regional nodal basin. Two patients had positive in-transit and regional SLNs. Three patients had negative in-transit SLNs but positive regional SLNs. The remaining 22 patients were negative for in-transit and regional SLNs.

CONCLUSIONS

In-transit SLNs may harbor micrometastasis. About 10% of the time, micrometastasis may involve the in-transit and not the regional SLN. Therefore, both in-transit and regional SLNs should be harvested.

Evaluation of sentinel lymph node status in spindle cell melanomas

BACKGROUND

The propensity for spindle cell melanoma to metastasize to the lymph node is relatively low despite its relative thick depth. To date, there are no published reports on the sentinel lymph node (SLN) status in patients diagnosed with spindle cell melanoma and desmoplastic malignant melanoma (DMM).

OBJECTIVE

Our purpose was to report our experience on the SLN status in spindle cell melanoma and DMM.

METHODS

We undertook a retrospective database and medical record review from Oct 21, 1993 to Sept 29, 1999. At the University of California at San Francisco Melanoma Center, patients with tumor thickness greater than 1 mm or less than 1 mm with high-risk features are managed with preoperative lymphoscintigraphy, selective SLN dissection, and wide excision.

RESULTS

Of 29 patients diagnosed with spindle cell melanoma and DMM, 28 had negative SLNs and are free of disease except for one patient who experienced splenic, bony, and brain metastases. The mean follow-up in this population was 16.5 and 11 months, respectively.

CONCLUSION

Our preliminary findings show that SLNs from patients diagnosed with spindle cell melanoma and DMM only rarely harbor micrometastasis despite their relative thickness. A larger number of cases from multicenter databases may further define the true biology of SLNs in this melanoma variant.

Computer databases for the sentinel lymph node program

At the University of California San Francisco Comprehensive Cancer Center, a computer database system was created using the FileMaker Pro database program. The system allows the clinical team to bring together data from all aspects of a multidisciplinary effort toward improving daily clinical management, for research, and ultimately, for the clinical standard of care for melanoma patients. With modest objectives during the initiation of the database, its adaptability has allowed it to become an integral link in all the efforts of the melanoma program. For the future, tapping into the immense potential of the Internet has begun to organize multicenter efforts. Through nationwide collaboration, the Sentinel Lymph Node Working Group will be able to follow, on a larger scale, the successes of the FileMaker pro database at the UCSF Comprehensive Cancer Center.

The human homolog of Escherichia coli Orn degrades small single-stranded RNA and DNA oligomers

We report here the identification of human homologues to the essential Escherichia coli Orn protein and the related yeast mitochondrial DNA-escape pathway regulatory factor Ynt20. The human proteins appear to arise from alternatively spliced transcripts, and are thus identical, except the human Ynt20 equivalent contains an NH(2)-terminal extension that possesses a predicted mitochondrial protease cleavage signal. In vitro analysis revealed that the smaller human protein exhibits a 3' to 5' exonuclease activity for small (primarily </=5 nucleotides in length) single-stranded RNA and DNA oligomers. We have named this human protein Sfn for small fragment nuclease to reflect its broad substrate range, and have termed the longer protein hSfnalpha. Sfn prefers Mn(2+) as a metal cofactor and displays a temperature-resistant (to 50 degrees C) nuclease activity. Kinetic analysis indicates that Sfn exhibits a similar affinity for small RNAs and DNAs (K(m) of approximately 1.5 micrometer), but degrades small RNAs approximately 4-fold more efficiently than DNA. Mutation of a conserved aspartate (Asp(136)) to alanine abolishes both nuclease activities of Sfn. Northern blot analysis revealed that a 1-kilobase transcript corresponding to SFN and/or SFNalpha (these mRNAs differ by only two nucleotides) is expressed at varying levels in all fetal and adult human tissues examined. Expressed tag sequence clone analysis found that the two splice variants, SFN to SFNalpha, are present at a ratio of roughly 4 to 1, respectively. The results presented within suggest a role for human Sfn in cellular nucleotide recycling.

Mapping the protein-DNA interface and the metal-binding site of the major human apurinic/apyrimidinic endonuclease

Apurinic/apyrimidinic (AP) endonuclease Ape1 is a key enzyme in the mammalian base excision repair pathway that corrects AP sites in the genome. Ape1 cleaves the phosphodiester bond immediately 5' to AP sites through a hydrolytic reaction involving a divalent metal co-factor. Here, site-directed mutagenesis, chemical footprinting techniques, and molecular dynamics simulations were employed to gain insights into how Ape1 interacts with its metal cation and AP DNA. It was found that Ape1 binds predominantly to the minor groove of AP DNA, and that residues R156 and Y128 contribute to protein-DNA complex stability. Furthermore, the Ape1-AP DNA footprint does not change along its reaction pathway upon active-site coordination of Mg(2+) or in the presence of DNA polymerase beta (polbeta), an interactive protein partner in AP site repair. The DNA region immediately 5' to the abasic residue was determined to be in close proximity to the Ape1 metal-binding site. Experimental evidence is provided that amino acid residues E96, D70, and D308 of Ape1 are involved in metal coordination. Molecular dynamics simulations, starting from the active site of the Ape1 crystal structure, suggest that D70 and E96 bind directly to the metal, while D308 coordinates the cation through the first hydration shell. These studies define the Ape1-AP DNA interface, determine the effect of polbeta on the Ape1-DNA interaction, and reveal new insights into the Ape1 active site and overall protein dynamics.

Xanthones and triterpenoids from the bark of Garcinia vilersiana

The hexane extract of the bark of Garcinia vilersiana from Vietnam contained four triterpenoids (olean-12-ene-3beta,11alpha-diol, lupeol, beta-amyrin and oleanolic acid), and six xanthones (globuxanthone, subelliptenone H, subelliptenone B, 12b-hydroxy-des-D-garcigerrin A, 1-O-methylglobuxanthone and symphoxanthone). The structure of 1-O-methylglobuxanthone, the only novel compound, was determined using 1D and 2D NMR techniques and by correlation with globuxanthone.

Dimensionality and reliability of the Civilian Mississippi Scale for PTSD in a postearthquake community

This study examines psychometric properties of the Civilian Mississippi Scale for posttraumatic stress disorder when administered in a community survey of 656 persons following the 1989 Loma Prieta earthquake. Internal consistency was lower (Cronbach's alpha = .73) than for previous analyses of civilian and combat versions of the Mississippi Scale. The analysis produced one strong factor composed of 25 items with regular wording and a second, weaker factor composed of 10 items with reversed wording. Internal consistency was higher when the 10 reversed items were removed (Cronbach's alpha = .86); the two factors were negatively correlated. Traumatic experiences and psychological distress measures explained more variance in the 25-item factor than in the 35-item scale. Further studies should focus on content analysis and performance of the reversed items.

Oral acyclovir after penetrating keratoplasty for herpes simplex keratitis

OBJECTIVE

To determine the efficacy of systemic acyclovir in decreasing complications and improving the outcome of penetrating keratoplasty for herpes simplex virus (HSV) keratitis.

METHODS

Retrospective study of 53 primary penetrating keratoplasties for HSV keratitis at an eye hospital from January 1, 1989, through December 31, 1996. Medical records were analyzed for history of HSV keratitis, preoperative neovascularization, and disease activity. Postoperative use of acyclovir, recurrence of HSV keratitis, rejection, uveitis or edema, and graft failure were evaluated.

RESULTS

Twenty-four patients (mean +/- SD follow-up, 44.7 +/- 32.6 months) received no acyclovir and were compared with 20 patients, (mean +/- SD follow-up, 28.8 +/- 16.7 months), who received 400 mg acyclovir twice a day for at least 1 year. No patient in the acyclovir group had a recurrence of dendritic keratitis in the first year compared with 5 (21%) of the patients who did not receive acyclovir (P = .03). No patient had graft failure in the acyclovir group compared with 4 (17%) in the group without acyclovir after 1 year of follow-up (P = .06).

CONCLUSION

Postoperative systemic acyclovir therapy after penetrating keratoplasty for HSV keratitis is associated with a reduced rate of recurrent HSV dendritic keratitis and possible graft failure at 1 year of follow-up.

Evidence that a single replication fork proceeds from early to late replicating domains in the IgH locus in a non-B cell line

In non-B cell lines, like the murine erythroleukemia cell line (MEL), the most distal IgH constant region gene, C alpha, replicates early in S; other heavy chain constant region genes, joining and diversity segments, and the most proximal Vh gene replicate successively later in S in a 3' to 5' direction proportional to their distance from C alpha. In MEL, replication forks detected in the IgH locus also proceed in the same 3' to 5' direction for approximately 400 kb, beginning downstream of the IgH 3' regulatory region and continuing to the D region, as well as within the Vh81X gene. Downstream of the initiation region is an early replicating domain, and upstream of Vh81X is a late replicating domain. Hence, the gradual transition between early and late replicated domains can be achieved by a single replication fork.

Injuries as a result of California earthquakes in the past decade

The devastating effects of earthquakes have been demonstrated repeatedly in the past decade, through moderate and major earthquakes such as the October 1987 Whittier Narrows earthquake (5.9 on the Richter scale), the October 1989 Loma Prieta earthquake (7.1) and the January 1994 Northridge earthquake (6.7). While 'official' tallies of injuries and deaths are reported for each event, the numbers vary from report to report. For Northridge, the number of injuries vary between 8,000 and 12,000; the number of deaths from 33 to 73 (Peek-Asa et al., 1997; Durkin, 1996). While official estimates are commonly reported following disasters, the study of actual numbers, types and causes of casualties has not developed. In this paper, we identify the numbers and risk factors for injuries within community-based samples across three earthquakes in urban California. We first report the numbers and types of injuries in each earthquake and then identify risk factors specifically associated with the Northridge earthquake.

Examining self-perceived first-aid abilities after the Northridge earthquake

INTRODUCTION

This study examines those factors predictive of self-perceived first-aid abilities among a community-based sample after the 1994 Northridge earthquake.

METHODS

A probabilities-proportionate-to-size (pps) sample of residents of Los Angeles Country and 11 pre-selected zip codes from southeastern Ventura County was selected using computer-generated random digit-dialing (rdd) procedures 7-11 months after the earthquake. Data were collected from 506 individuals in 45 minute interviews. A unidimensional scale of self-perceived first-aid ability was created and represents the dependent variable in a causal path model.

RESULTS

In a causal path model, standardized path coefficients suggested that while reports of taking first-aid courses were the most influential factors in predicting higher self-perceived first-aid abilities, other factors including being white, younger, speaking English in the home, and lower income also predicted higher self-perceived first-aid abilities that were independent from taking formal first-aid courses.

CONCLUSIONS

First-aid training should be directed towards target segments of the population that are not likely to have had instruction in these basic skills. Those individuals who self-report high first-aid proficiency, independent of formal first-aid training, should be evaluated to assess their abilities to perform these skills.

Asthma in a Vietnamese refugee population

Asians and Pacific Islanders comprise a large and growing minority group in the United States, yet data on health status specific to these populations are scant. We conducted an epidemiologic study of asthma in a Vietnamese refugee population to estimate prevalence, evaluate risk factors, and better understand treatments of asthma among Vietnamese individuals. One hundred twenty-four asthma cases were identified from a population of 2,536 new Vietnamese refugees in San Diego (prevalence = 49 per 1,000; 4.9%). Two nonasthmatic control groups of Vietnamese refugees, matched for age and gender with the asthma cases, were recruited for a case-control study, using a questionnaire administered in Vietnamese. Vietnamese asthmatic individuals used both Western and non-Western therapies. Most subjects used traditional health practices, such as coining, cupping, and oil inhalation. As compared with current-refugee controls, the asthmatic subjects used significantly more bleeding (OR: 3.40; 95% CI: 1.06 to 10.80) and herbal ingestion (OR: 1.87; 95% CI: 1.08 to 3.19). As compared with former-refugee controls, the asthmatic subjects used significantly more oil inhalation (OR: 2.58; 95% CI: 1.45 to 4.85), bleeding (OR: 8.64, 95% CI: 1.02 to 73.70), and herbal ingestion (OR: 1.93; 95% CI: 1.02 to 3.67). The presentation and recognition of asthma among the Vietnamese subjects were similar to those in other populations. This information may be helpful in designing culture-specific health-education programs.

Comparative analysis of the interactions of Escherichia coli sigma S and sigma 70 RNA polymerase holoenzyme with the stationary-phase-specific bolAp1 promoter

We have investigated the interactions of Escherichia coli sigma 70 and sigma S holoenzyme RNA polymerases (E sigma S and E sigma 70) with the stationary-phase-specific bolAp1 promoter by various footprinting methods in vitro. E sigma S and E sigma 70 have been shown to transcribe the bolApl promoter in vitro. We have determined the effects of salt and holoenzyme concentrations on E sigma S and E sigma 70 open complex formation at the bolAp1 promoter in vitro. We have obtained a high-resolution hydroxyl radical (OH.) footprint of E sigma S and E sigma 70 on the bolApl promoter. The OH. footprinting data show remarkable similarities between the footprints of the heparin-resistant transcription complexes of the two holoenzymes which have the same +1 transcription start site. However, there are distinctive differences in the protection patterns in the region between -20 and -10 of the bolAp1 promoter. KMnO4 reactivity assays reveal that, at 37 degrees C, both holoenzymes produced similar but not identical patterns of reactivities.

Epitope mapping using histidine-tagged protein fragments: application to Escherichia coli RNA polymerase sigma 70

We present a simple, rapid, and inexpensive method for mapping epitopes of monoclonal antibodies using His-tagged protein fragments. In essence, four steps are involved: (i) purify overproduced His-tagged protein from inclusion body; (ii) fragment the protein by partial chemical or enzymatic hydrolysis and isolate the His-tagged peptides with a Ni(2+)-chelate column to generate a "ladder" containing a distribution of peptide fragment sizes; (iii) fractionate the isolated peptides by SDS-polyacrylamide gel electrophoresis and probe the ladder by immunoblot analysis; (iv) determine the size of the fragments that do and do not bind the monoclonal antibody using size markers specific to the His-tagged protein being studied. We have applied this method successfully to map the epitope positions of known and new monoclonal antibodies to Escherichia coli sigma 70. We believe this method will find broad application.

Overproduction and purification of sigmaS, the Escherichia coli stationary phase specific sigma transcription factor

This paper reports the overproduction and the details of a rapid method to purify active sigmaS monomers from a T7 RNA polymerase-based protein expression system. This 2-day procedure involves solubilizing inclusion bodies in sarkosyl detergent, removal of sarkosyl by dialysis, and a single gel filtration column chromatography step. The final yield of sigmaS is about 9 mg of approximately 92% purity from 0.5 g of wet weight cells. Overproduced sigmaS binds to core RNA polymerase and supports transcription from the bolAp1 promoter, a sigmaS-dependent promoter.

The leucine-responsive regulatory protein (Lrp) acts as a specific repressor for sigma s-dependent transcription of the Escherichia coli aidB gene

The product of the Escherichia coli aidB gene is homologous to human isovaleryl-coenzyme A dehydrogenase (IVD), an enzyme involved in the breakdown of the amino acid leucine. The aidB gene is not expressed constitutively, but its transcription is induced via distinct mechanisms in response to: (i) exposure to alkylating agents; (ii) acetate at a slightly acidic pH; and (iii) anoxia. Induction by alkylating agents is mediated by the transcriptional activator Ada, in its methylated form (meAda); the other forms of induction are Ada independent and require sigma s, the alternative sigma factor mainly expressed during the stationary phase of bacterial growth. In this report we show that, in the absence of any transcriptional factor, aidB is efficiently transcribed in vitro by the sigma s, but not by the sigma 70, form of RNA polymerase holoenzyme. In the presence of meAda, levels of transcription by both forms of RNA polymerase are significantly increased. However, sigma s-dependent transcription of aidB is inhibited both in vitro and in vivo by binding of the transcriptional regulator Lrp (leucine responsive protein) to the aidB promoter region (PaidB). Lrp acts as a specific repressor for sigma s-dependent transcription of aidB. Leucine counteracts Lrp binding to P aidB, as does binding to P aidB of me Ada, which causes Lrp to dissociate from the promoter. The physiological significance of aidB transcription regulation is discussed.

Using the brief symptom inventory to profile monolingual Spanish-speaking psychiatric outpatients

As part of a larger study (Acosta, Evans, Hurwicz, & Yamamoto, 1987), a translated version of the Brief Symptom Inventory (BSI) was given to 153 monolingual Spanish-speaking psychiatric outpatients in the Los Angeles area. The raw mean scores on the nine primary symptom dimensions and the Global Severity Index (GSI) of the Spanish-speaking population were compared with the published raw mean scores of a normative sample of English-speaking psychiatric outpatients. Results suggested that the Spanish-speaking population had higher symptom levels on several dimensions and the GSI. It was suggested that the BSI could be a potentially useful instrument for self-reported psychiatric symptomatology among the Spanish-speaking population if an appropriate translation of the BSI were used.

Synthesis of the stationary-phase sigma factor sigma s is positively regulated by ppGpp

Strains of Escherichia coli which lack detectable guanosine 3',5'-bispyrophosphate (ppGpp) display a pleiotropic phenotype that in some respects resembles that of rpoS (katF) mutants. This led us to examine whether ppGpp is a positive regulator of sigma s synthesis. sigma s is a stationary-phase-specific sigma factor that is encoded by the rpoS gene. We found that a ppGpp-deficient strain is defective in sigma s synthesis as cells enter stationary phase in a rich medium, as judged by immunoblots. Under more-defined conditions we found that the stimulation of sigma s synthesis following glucose, phosphate, or amino acid starvation of wild-type strains is greatly reduced in a strain lacking ppGpp. The failure of ppGpp-deficient strains to synthesize sigma s in response to these starvation regimens could indicate a general defect in gene expression rather than a specific dependence of rpoS expression on ppGpp. We therefore tested the effect of artificially elevated ppGpp levels on sigma s synthesis either with mutations that impair ppGpp decay or by gratuitously inducing ppGpp synthesis with a Ptac::relA fusion. In both instances, we observed enhanced sigma s synthesis. Apparently, ppGpp can activate sigma s synthesis under conditions of nutrient sufficiency as well as during entry into stationary phase. This finding suggests that changes in ppGpp levels function both as a signal of imminent stationary phase and as a signal of perturbations in steady-state growth.

In vitro functional characterization of overproduced Escherichia coli katF/rpoS gene product

The katF/rpoS gene product (sigma s), a central regulator of stationary-phase gene expression in Escherichia coli, has been purified from an overproducing strain. sigma s was used as an immunogen for the production of monoclonal antibodies. Previous sequence analysis of sigma s strongly indicated homology to the sigma factor family. We show biochemically in this paper that sigma s is a sigma factor. This protein can bind to core RNA polymerase (E), and this binding can be competed effectively by the major E. coli transcription initiation factor, sigma 70. Immunopurified sigma s holoenzyme (E sigma s) transcribes the promoters of the bolAp1 gene and the xthA gene. Interestingly, both promoters can also be transcribed by sigma 70 holoenzyme (E sigma 70).

Overproduction and purification of sigma 32, the Escherichia coli heat shock transcription factor

This paper reports the overproduction and the details of a rapid method to purify active sigma 32 that is free of core RNA polymerase enzyme. Maximal overproduction of sigma 32 in a T7 RNA polymerase-based expression system is achieved only in the presence of rifampicin. This 2-day procedure involves solubilizing inclusion bodies in Sarkosyl, removal of Sarkosyl by dialysis, and a single S-Sepharose column chromatography step. The final yield of sigma 32 is about 4.1 mg of approximately 95% purity from 1 g of wet weight cells.

Replication-defective mutants of herpes simplex virus (HSV) induce cellular immunity and protect against lethal HSV infection

Live viruses and live virus vaccines induce cellular immunity more readily than do inactivated viruses or purified proteins, but the mechanism by which this process occurs is unknown. A trivial explanation would relate to the ability of live viruses to spread and infect more cells than can inactivated virus. We have used live but replication-defective mutants to investigate this question. Our studies indicate that the immune responses of mice to live virus differ greatly from the responses to inactivated virus even when the virus does not complete a replicative cycle. Further, these studies indicate that herpes simplex virus-specific T-cell responses can be generated by infection with replication-defective mutant viruses. These data indicate that the magnitude of the cellular immunity to herpes simplex virus may be proportional to the number or quantity of different viral gene products expressed by an immunizing virus.

S. cerevisiae TFIIIB is the transcription initiation factor proper of RNA polymerase III, while TFIIIA and TFIIIC are assembly factors

The S. cerevisiae RNA polymerase III (pol III) transcription factor TFIIIB binds to DNA upstream of the transcription start site of the SUP4 tRNA(Tyr) gene in a TFIIIC-dependent reaction and to the major 5S rRNA gene in a reaction requiring TFIIIC and TFIIIA. It is shown here that TFIIIB alone correctly positions pol III for repeated cycles of transcription on both genes, with the same efficiency as fully assembled transcription complexes. Thus, TFIIIB is the sole transcription initiation factor of S. cerevisiae pol III; TFIIIC and TFIIIA are assembly factors for TFIIIB. The TFIIIB-dependent binding of pol III to the SUP4 tRNA and 5S rRNA genes has been analyzed in binary (protein and DNA only) and precisely arrested ternary (protein, DNA, and RNA) transcription complexes. Pol III unwinds at least 14 bp of DNA at the SUP4 transcription start in a temperature-dependent process. The unwound DNA segment moves downstream with nascent RNA as a transcription bubble of approximately the same size.

Transcription factor IIIB generates extended DNA interactions in RNA polymerase III transcription complexes on tRNA genes

Transcription complexes that assemble on tRNA genes in a crude Saccharomyces cerevisiae cell extract extend over the entire transcription unit and approximately 40 base pairs of contiguous 5'-flanking DNA. We show here that the interaction with 5'-flanking DNA is due to a protein that copurifies with transcription factor TFIIIB through several steps of purification and shares characteristic properties that are normally ascribed to TFIIIB: dependence on prior binding of TFIIIC and great stability once the TFIIIC-TFIIIB-DNA complex is formed. SUP4 gene (tRNATyr) DNA that was cut within the 5'-flanking sequence (either 31 or 28 base pairs upstream of the transcriptional start site) was no longer able to stably incorporate TFIIIB into a transcription complex. The TFIIIB-dependent 5'-flanking DNA protein interaction was predominantly not sequence specific. The extension of the transcription complex into this DNA segment does suggest two possible explanations for highly diverse effects of flanking-sequence substitutions on tRNA gene transcription: either (i) proteins that are capable of binding to these upstream DNA segments are also potentially capable of stimulating or interfering with the incorporation of TFIIIB into transcription complexes or (ii) 5'-flanking sequence influences the rate of assembly of TFIIIB into stable transcription complexes.

Transsynaptic degeneration of motoneurones caudal to spinal cord lesions

We studied the effects of complete transversal section of the spinal cord, at T8-10, in adult rats, upon the number and morphology of identified motoneurones in lumbar segments L4 and L5. In observations by light and electron microscopy many lumbar motoneurones had structural abnormalities when the interval between surgery and perfusion ranged between a few hours and one week. We found also that as many as 25% of the motoneurones distal to a cord transection disappeared as a consequence of the lesions. We did not find comparable changes in the spinal cord at C6 after transection at T8-10. Complete removal of the cerebellum did not reduce the lumbar motoneurone counts. Bilateral ablation of the "motor" cortex did cause a reduction of motoneurone counts at L4-5; these animals showed normal or near normal spontaneous locomotor activity beginning a few days after the lesion was placed. Motoneurone counts were significantly reduced after partial cord lesions that spared the dorsal funiculi (where the corticospinal tract travels in the rat), but in this case the rats were paraplegic as a result of the lesion. Cord transection at 7 days of postnatal age resulted in reduced motoneurone counts when the rats reached adulthood. Intraspinal or subarachnoid administration of colchicine led to reduced motoneurone counts. Prolonged infusion of a GABA agonist, muscimol, into the lumbar CSF did not prevent the loss of motoneurones produced by cord transection. Pretreatment of animals with a Ca2+ channel blocker (nimodipine) did not prevent the effects of cord transection.(ABSTRACT TRUNCATED AT 250 WORDS)

Recovery of locomotor function after hemisection of the spinal cord in cats

Cats were subjected to high lumbar hemisection of the spinal cord, on the right side. The initial paralysis of the right hindlimb became rapidly attenuated, and they walked again in one week or less after surgery. Minor residual deficits in gait remained, that may be permanent. Electrical stimulation of the bulbar reticulospinal formation showed residual crossed connections reaching the right lumbosacral cord via the left hemicord. Recovery from Brown-Séquard's syndrome may be primarily due to the survival of low crossing descending projections to the spinal cord.

Locomotor control in macaque monkeys

We carried out experiments on young adult macaque monkeys (M.fascicularis) in an attempt to establish whether or not primates possess a locomotor control system consisting of spinal pattern generators modulated by brain-stem locomotor regions. We could not induce 'spinal stepping' in our subjects after spinal cord transection. Sparing of pathways contained in the central sector of the white matter of the cord was sufficient for stepping and walking. 'Controlled locomotion' was elicited in thalamic monkeys by electrical stimulation of the posterior subthalamic region or the midbrain tegmentum just ventral to the inferior colliculi. We conclude that there are significant homologies between this primate species and the cat regarding the probable existence of supraspinal locomotor control structures, but it seems that the presumed spinal step generators in monkeys depend more on supraspinal inputs than they do in cats.