Management of Oncogene Driven Locally Advanced Unresectable Non-small Cell Lung Cancer

INTRODUCTION

The current standard of care of locally advanced non-small cell lung cancer (LA-NSCLC) is concurrent chemoradiation, followed by consolidation durvalumab. However, there is evidence that the efficacy of chemoradiation and also immunotherapy in many oncogene-positive LA-NSCLC are attenuated, and dependent on the subgroup.

AREAS COVERED

We will firstly review the outcomes of standard-of-care therapy in oncogene-driven LA-NSCLC. We looked at various oncogene driven subgroups and the tumor microenvironment that may explain differential response. Finally, we review the role of targeted therapy in the treatment of LA-NSCLC.

EXPERT OPINION

Each oncogene-positive subgroup should be treated as its own entity, and continued efforts should be undertaken to incorporate targeted therapy, which is likely to yield superior survival outcomes if trial design can be optimized and toxicities can be managed.

Clinical outcome and prognostic factors for Asian patients in Phase I clinical trials

BACKGROUND

Patient selection is key in Phase I studies, and prognosis can be difficult to estimate in heavily pre-treated patients. Previous prognostic models like the Royal Marsden Hospital (RMH) score or using the neutrophil-lymphocyte ratio (NLR) have not been validated in current novel therapies nor in the Asian Phase I population.

METHODS

We conducted a retrospective review of 414 patients with solid tumours participating in Phase I studies at our centre between October 2013 and December 2020.

RESULTS

The RMH model showed poorer prognosis with increasing scores [RMH score 1, HR 1.28 (95% CI: 0.96-1.70); RMH score 2, HR 2.27 (95% CI: 1.62-3.17); RMH score 3, HR 4.14 (95% CI: 2.62-6.53)]. NLR did not improve the AUC of the model. Poorer ECOG status (ECOG 1 vs. 0: HR = 1.59 (95% CI = 1.24-2.04), P < 0.001) and primary tumour site (GI vs. breast cancer: HR = 3.06, 95% CI = 2.16-4.35, P < 0.001) were prognostic.

CONCLUSIONS

We developed a NCIS prognostic score with excellent prognostic ability for both short-term and longer-term survival (iAUC: 0.71 [95% CI 0.65-0.76]), and validated the RMH model in the largest Asian study to date.

DNA damage repair gene mutations predict the efficacy of platinum-based chemotherapy and immunotherapy plus platinum-based chemotherapy in advanced non-small cell lung cancer: a retrospective Chinese cohort study

Background

Platinum-based chemotherapy (PC) and immunotherapy plus platinum-based chemotherapy (IPC) remain the first-line treatment for advanced NSCLC. But only a minority patients benefit from PC, and existing biomarkers, such as PD-L1, have been shown to be defective in predicting the efficacy of IPC. Highlighting the need to identify novel biomarkers for the efficacy of PC and IPC. DNA damage repair (DDR) mutations are known to predict response to PC in solid tumors. However, the predictive value of DDR in PC and IPC of NSCLC remains unclear.

Methods

Patients diagnosed with advanced or metastatic NSCLC were retrospectively included if they underwent next generation sequencing prior to starting treatment. Primary endpoints were to explore whether DDR mutations (DDRmut) are associated with clinical outcomes of PC and IPC. Secondary end point were to explore the association between DDRmut and the choice to add immunotherapy to chemotherapy, and the impact of different DDR pathways on efficacy in PC and IPC.

Results

DDRmut showed a strong association with tumor mutation burden-high (TMB-H) versus DDR wild-type (DDRwt) and higher rates of PD-L1 TPS ≥50% positivity. In 63 patients treated with PC, ORRs were 15.38% and 2.86% for DDRmut and DDRwt subgroup (P=0.1536), and DCRs were 88.46% and 45.72% (P=0.00097) at 6 months after PC. The DDRmut patients had significantly improved median PFS (mPFS) and median overall survival (mOS) than DDRwt group (mPFS: 7.6 vs. 3.9 months, HR =1.93, 95% CI: 1.09 to 3.14, P=0.0220. mOS: 29.9 vs. 20.7 months, HR =2.31, 95% CI: 1.09 to 4.9, P=0.0250). Moreover, among 37 patients treated with IPC, ORRs were 45% and 11.76% for DDRmut and DDRwt patients (P=0.0365), and the DCRs were 95% and 70.58% (P=0.0752), respectively at 6 months after IPC. The DDRmut patients had significantly improved mPFS compared to the DDRwt group (19.5 vs. 4.5 months, HR =3.28, 95% CI: 1.53 to 9.56, P=0.0022). In DDRmut group, mPFS of IPC recipients was significantly better than that of PC recipients (19.5 vs. 7.6 months, HR =2.09, 95% CI: 0.98 to 4.42, P=0.050).

Conclusions

There is potential for DDR to serve as a positive predictor of PC and IPC in advanced NSCLC patients.

Clinical characteristics and genetic testing outcome of suspected hereditary peripheral nerve sheath tumours in a tertiary cancer institution in Singapore

Background

Peripheral Nerve Sheath Tumors (PNST) are a diverse group of mostly benign tumours uncommon in the general population. About 5–10% of PNSTs are hereditary, predominantly arising from germline variants in NF1, NF2, SMARCB1, or LZTR1 gene.

Methods

We reviewed the clinical characteristics and genetic testing results of patients referred to the NCIS Adult Cancer Genetics Clinic for suspected hereditary PNST.

Results

3,001 patients suspected to have various hereditary cancer syndromes were evaluated between year 2000 to March 2021. 13 (0.4%) were clinically diagnosed to have hereditary PNSTs. The majority were male (54%), with a median age at presentation to the genetics clinic of 29 years (range 19–48). 11/13 (85%) patients had multiple PNSTs, 12/13 (92%) had young onset PNSTs, 5/13 (38.5%) had personal and family history of PNST. 11/13 patients (85%) had clinical features of neurofibromatosis type 1 (NF1) including one patient who also fulfilled clinical criteria of neurofibromatosis type 2 (NF2); 2/13 (14%) had multiple schwannomas. Four patients underwent multi-gene panel testing, including one patient with clinical NF1, one patient who met both clinical NF1 and NF2 criteria, and two patients with multiple schwannomas. The patient with clinical features of NF1 was heterozygous for a pathogenic c. 2033dup variant in the NF1 gene. The patient with both NF1/NF2 features was heterozygous for a novel c.732 T > A nonsense variant in the NF2 gene. The two patients with multiple schwannomas were heterozygous for a pathogenic/likely pathogenic variant in the LZTR1 gene and are the first LZTR1-positive schwannomatosis patients reported in Asia.

Conclusion

Hereditary PNSTs are rare referrals to an adult cancer genetics clinic. NF1 is the most common PNST seen. LZTR1 variants may be the underlying cause in Asian patients with multiple schwannomatosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13053-022-00230-4.

Design and Multicenter Clinical Validation of a 3-Dimensionally Printed Nasopharyngeal Swab for SARS-CoV-2 Testing

Importance

Three-dimensionally printed nasopharyngeal swabs (3DP swabs) have been used to mitigate swab shortages during the coronavirus disease 2019 (COVID-19) pandemic. Clinical validation for diagnostic accuracy and consistency, as well as patient acceptability, is crucial to evaluate the swab's performance.

Objective

To determine the accuracy and acceptability of the 3DP swab for identifying severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Design, Setting, and Participants

A diagnostic study was conducted from May to July 2020 at 2 tertiary care centers in Singapore with different reference swabs (FLOQSwab [COPAN Diagnostics] or Dacron swab [Deltalab]) and swab processing techniques (wet or dry) to evaluate the performance of the 3DP swab compared with traditional, standard-of-care nasopharyngeal swabs used in health care institutions. The participants were patients with COVID-19 in the first 2 weeks of illness and controls with acute respiratory illness with negative test results for SARS-CoV-2. Paired nasopharyngeal swabs were obtained from the same nostril and tested for SARS-CoV-2 by reverse-transcriptase polymerase chain reaction. The sequence of swabs was randomized based on odd and even participant numbers.

Main Outcomes and Measures

Primary outcome measures were overall agreement (OA), positive percentage agreement (PPA), and negative percentage agreement of the 3DP swab compared with reference swabs. Secondary outcome measures were the correlation of cycle threshold (Ct) values of both swabs.

Results

The mean (SD) age of participants was 45.4 (13.1) years, and most participants were men (87 of 89 [97.8%]), in keeping with the epidemiology of the COVID-19 pandemic in Singapore. A total of 79 patients with COVID-19 and 10 controls were recruited. Among the patients with COVID-19, the overall agreement and PPA of the 3DP swab was 91.1% and 93.5%, respectively, compared with reference swabs. The PPA was 100% for patients with COVID-19 who were tested within the first week of illness. All controls tested negative. The reverse-transcriptase polymerase chain reaction Ct values for the ORF1ab and E-gene targets showed a strong correlation (intraclass correlations coefficient, 0.869-0.920) between the 3DP and reference swab on independent testing at each institution despite differences in sample processing. Discordant results for both gene targets were observed only at high Ct values.

Conclusions and Relevance

In this diagnostic study of 79 patients with COVID-19 and 10 controls, the 3DP swab performed accurately and consistently across health care institutions and could help mitigate strained resources in the escalating COVID-19 pandemic.

Clinical Diagnostic Study of a Novel Injection Molded Swab for SARS-Cov-2 Testing

Introduction

The gold standard for COVID-19 diagnosis is currently a real-time reverse transcriptase polymerase chain reaction (RT-PCR) to detect SARS-CoV-2. This is most commonly performed on respiratory secretions obtained via a nasopharyngeal swab. Due to supply chain limitations and high demand worldwide because of the COVID-19 pandemic, access to commercial nasopharyngeal swabs has not been assured. 3D printing methods have been used to meet the shortfall. For longer-term considerations, 3D printing may not compare well with injection molding as a production method due to the challenging scalability and greater production costs of 3D printing.

Methods

To secure sufficient nasopharyngeal swab availability for our national healthcare system, we designed a novel injection molded nasopharyngeal swab (the IM2 swab). We performed a clinical diagnostic study comparing the IM2 swab to the Copan FLOQSwab. Forty patients with a known diagnosis of COVID-19 and 10 healthy controls were recruited. Paired nasopharyngeal swabs were obtained from the same nostril of each participant and tested for SARS-CoV-2 by RT-PCR.

Results

When compared to the Copan FLOQswab, results from the IM2 swab displayed excellent overall agreement and positive percent agreement of 96.0% and 94.9%, respectively. There was no significant difference in mean RT-PCR cycle threshold values for the ORF1ab (28.05 vs. 28.03, p = 0.97) and E-gene (29.72 vs. 29.37, p = 0.64) targets, respectively. We did not observe any significant adverse events and there was no significant difference in patient-reported pain.

Conclusion

In summary, the IM2 nasopharyngeal swab is a clinically safe, highly accurate option to commercial nasopharyngeal swabs.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40121-020-00391-6.

Range of Varicella Zoster Co-Infections with COVID-19, Singapore

There have been recent descriptions of the novel coronavirus disease 2019 (COVID-19) presenting as 'varicella-like exanthem'. We report three cases of patients with Varicella-Zoster Virus (VZV) and COVID-19 co-infections, presenting in three varied ways. These cases highlight the need for heightened alertness to how such co-infections can present, to pick up overlapping 'dual pathologies' during this current pandemic given that infection control measures including airborne precautions are crucial for both COVID-19 and VZV.

Roadmap Out of COVID-19

The recent coronavirus disease (COVID-19) was declared as a public health emergency by the World Health Organisation on 30th January 2020, and has now affected more than 100 countries. Healthcare institutions and governments worldwide have raced to contain the disease, albeit to varying degrees of success. Containment strategies adopted range from complete lockdowns to remaining open with public advisories regarding social distancing. However, general principles adopted by most countries remain the same, mainly to avoid gatherings in large numbers and limit social interactions to curb the spread of disease. In Singapore, this disease had a very different progression. The first wave of the disease started with the confirmation of the first COVID-19 positive patient in Singapore on 23rd January 2020. Initially, the daily number of confirmed cases were low and manageable. With a rise in unlinked cases, the Disease Outbreak Response System Condition (DORSCON) status was raised from yellow to orange. New cluster outbreaks in foreign worker dormitories led to the rampant spread of disease, with daily spikes of COVID-19 cases. As of 7th June 2020, we have a total of 37,910 confirmed cases of COVID-19 infections, the highest in Southeast Asia, 12,999 active cases and a manageable mortality count of 25 deaths. This details our unique method for dealing with a pandemic, including a brief demographic of trauma patients during this period. We were able to conserve sufficient resources to ensure that our essential services can still continue. Moving on, we have to ensure the continued protection of our population, especially the vulnerable groups such as the elderly and the immunocompromised, as we reopen.

Four Patients with COVID-19 and Tuberculosis, Singapore, April-May 2020

Coronavirus disease (COVID-19) and tuberculosis (TB) developed in 4 foreign workers living in dormitories in Singapore during April–May 2020. Clinical manifestations and atypical radiographic features of COVID-19 led to the diagnosis of TB through positive interferon-gamma release assay and culture results. During the COVID-19 pandemic, TB should not be overlooked.

Increased drug resistance is associated with reduced glucose levels and an enhanced glycolysis phenotype

BACKGROUND AND PURPOSE

The testing of anticancer compounds in vitro is usually performed in hyperglycaemic cell cultures, although many tumours and their in vivo microenvironments are hypoglycaemic. Here, we have assessed, in cultures of tumour cells, the effects of reduced glucose levels on resistance to anticancer drugs and investigated the underlying cellular mechanisms.

EXPERIMENTAL APPROACH

PIK3CA mutant (AGS, HGC27), and wild-type (MKN45, NUGC4) gastric cancer cells were cultured in high-glucose (HG, 25 mM) or low-glucose (LG, 5 mM) media and tested for sensitivity to two cytotoxic compounds, 5-fluorouracil (5-FU) and carboplatin, the PI3K/mTOR inhibitor, PI103 and the mTOR inhibitor, Ku-0063794.

KEY RESULTS

All cells had increased resistance to 5-FU and carboplatin when cultured in LG compared with HG conditions despite having similar growth and cell cycle characteristics. On treatment with PI103 or Ku-0063794, only the PIK3CA mutant cells displayed increased resistance in LG conditions. The PIK3CA mutant LG cells had selectively increased p-mTOR, p-S6, p-4EBP1, GLUT1 and lactate production, and reduced reactive oxygen species, consistent with increased glycolysis. Combination analysis indicated PI103 and Ku-0063794 were synergistic in PIK3CA mutant LG cells only. Synergism was accompanied by reduced mTOR signalling and increased autophagy.

CONCLUSIONS AND IMPLICATIONS

Hypoglycaemia increased resistance to cytotoxic agents, especially in tumour cells with a high dependence on glycolysis. Dual inhibition of the PI3K/mTOR pathway may be able to attenuate such hypoglycaemia-associated resistance.

Venous thromboembolism prophylaxis in acute medical admissions to a university teaching hospital

The objective of this study was to assess appropriate thromboprophylaxis prescription rates in a university hospital and to re-audit after a series of interventions. The notes of all acute medical patient admissions over a 4-week period were assessed for VTE risk factors and prescription of thromboprophylaxis. Subsequently, a series of hospital wide interventions including educational initiatives and a new drug prescription chart were introduced. 2 years post intervention the audit was repeated. Pre-intervention, 104 of 265 (39%) "at risk" patients were prescribed appropriate thromboprophylaxis. Post intervention the prescription rate increased to 108 of 188 (57%) "at risk patients". The results of the pre- intervention audit are consistent with the published literature. While there was a significant increase in prescription rates post intervention, over 40% of "at risk" patients still did not receive thromboprophylaxis highlighting the challenge in attempting to close the gap between guidelines and actual practice.

Serum resistin is not associated with obesity or insulin resistance in humans

BACKGROUND

Resistin has proposed link with obesity related insulin resistance and type 2 diabetes. The physiologic role of resistin in humans remains unknown. It is suggested that circulating resistin levels are not associated with obesity or insulin resistance in humans. However, the effects of weight loss on serum resistin concentration has not been studied. In order to better understand the physiologic role of resistin in human obesity, we measured the serum resistin concentration in subjects with severe obesity (before and after 6-months of dietary intervention) to test the hypothesis that serum resistin concentrations are elevated amongst individuals with severe obesity and weight loss would reduce these levels.

METHODS

Seventy-one obese subjects (defined as BMI > 35 kg/m2) who were randomized to low fat (LF) vs low carbohydrates (LC) diets and who completed the 6-month follow-up were studied. Their baseline demographic information was collected and serum resistin, insulin, glucose were measured at baseline and at 6-months.

RESULTS

Subjects in LC diet lost more weight than LF (-19.54 +/- 7.87 lbs vs -7.83 +/- 11.23 lbs., p = 0.001). Insulin sensitivity (HOMA) improved in LC group compared with LF group [-3.72 +/- 9.84 (LC) vs +1.31 +/- 7.31 (LF), p = 0.006]. Serum resistin levels did not decrease in either diet.

CONCLUSIONS

Our study found that despite a significant weight loss and improvement in insulin sensitivity there was no reduction in serum resistin concentration in morbidly obese men with metabolic syndrome suggesting that resistin does not play a central role in obesity related insulin resistance.

The disability profile of patients with schizophrenia in psychiatric hospital and community settings in Singapore

The disability profile of persons with schizophrenia in Singapore and how disability levels vary in patients cared for in the community and in the long-stay wards of a state mental hospital were studied using the Life Skills Profile (LSP). The inter-rater reliability of the LSP assessed by the intraclass correlation coefficient (ICC), was lower than in the Australian studies. The test-retest ICCs for the total LSP score and the five subscale scores were satisfactory for the hospitalised subjects and for the community psychiatric nurse subjects, but generally poor for the community care facility subjects. The average ICCs were lower compared to the Australian study. Female hospitalised subjects but not male hospitalised subjects returned higher disability scores on all LSP scales compared to community subjects. This study provided some preliminary data on the usefulness and validity of the LSP in a multi-ethnic Asian setting like Singapore. If the LSP is used as a measure of disability in schizophrenia, it would appear that ratings should only be made by those who know the subject well, and that raters should be formally trained mental health professionals.

A comparative mental health literacy survey of psychiatrists and other mental health professionals in Singapore

OBJECTIVE

The objectives of this study are, first, to replicate and extend an Australian approach to assessing mental health literacy by studying a sample of Singapore mental health professionals, and to focus on differences between judgements made by the psychiatrists in comparison with the other mental health professionals. Second, to compare the psychiatrists' judgements with those of Australian psychiatrists.

METHOD

The Australian questionnaire, assessing responses in relation to vignettes of major depression and to schizophrenia was extended by adding a third vignette of mania, and by the addition of several region-specific response options. Nearly 500 questionnaires were distributed to representative staff (psychiatrists, nurses and allied health) of a large psychiatric institution in Singapore, with a response rate of 81%. Psychiatrists' judgements were compared with all other hospital staff, and with Australian psychiatrists' judgements.

RESULTS

The two principal contrast groups (Singapore psychiatrists and other Singapore mental health professionals) differed slightly in terms of diagnostic accuracy. The psychiatrists differed in favouring a more professionally focused model of intervention, while both professional groups viewed traditional healers and their practices as distinctly unhelpful. Direct comparison of psychiatrist ratings generated in Singapore and in Australia revealed quite similar response profiles.

CONCLUSIONS

In addition to generating data of some intrinsic importance, comparison with Australian survey data allows the potential impact of regional and cultural differences, as well as of varying psychiatric practices, to be identified. Responses identified more similarities than differences in the judgements of the psychiatrists from the two countries.

Mental health literacy in Singapore: a comparative survey of psychiatrists and primary health professionals

OBJECTIVES

To assess the beliefs amongst health professionals in Singapore about management of 3 major mental disorders, comparing psychiatrists and a sample of primary care physicians, and so identify target areas for the education of primary health professionals.

MATERIALS AND METHOD

A questionnaire earlier distributed to psychiatrists at Woodbridge Hospital was posted to both Singapore general practitioners and polyclinic doctors. The questionnaire assessed the capacity of respondents to identify vignettes of depression, schizophrenia or mania, and then assessed respondents' views about the likely helpfulness of a number of interventions.

RESULTS

The psychiatrists and primary health professionals differed little in terms of diagnostic accuracy for depression and schizophrenia; however, only half the general practitioners and three-quarters of the polyclinic doctors correctly diagnosed mania, which was consistently diagnosed by the psychiatrists. A number of distinct differences were identified between the groups concerning the likely helpfulness and disorder specificity of various psychotropic drugs. The primary health physicians were more likely to favour non-specific management approaches, whilst the psychiatrists generally supported a focused biological approach to treatment, especially for the psychotic disorders. Some of the differences in beliefs about mental health management may well be contributed by the different patients treated by each group of clinicians.

CONCLUSIONS

The findings have important clinical implications in terms of diagnosing common psychiatric conditions accurately and giving us professionals' views about a range of interventions for such conditions, while also assisting review of educational programmes for identifying and managing major mental disorders.

The Bradyrhizobium japonicum nolA gene encodes three functionally distinct proteins

Examination of nolA revealed that NolA can be uniquely translated from three ATG start codons. Translation from the first ATG (ATG1) predicts a protein (NolA1) having an N-terminal, helix-turn-helix DNA-binding motif similar to the DNA-binding domains of the MerR-type regulatory proteins. Translation from ATG2 and ATG3 would give the N-terminally truncated proteins NolA2 and NolA3, respectively, lacking the DNA-binding domain. Consistent with this, immunoblot analyses of Bradyrhizobium japonicum extracts with a polyclonal antiserum to NolA revealed three distinct polypeptides whose molecular weights were consistent with translation of nolA from the three ATG initiation sites. Site-directed mutagenesis was used to produce derivatives of nolA in which ATG start sites were sequentially deleted. Immunoblots revealed a corresponding absence of the polypeptide whose ATG start site was removed. Translational fusions of the nolA mutants to a promoterless lacZ yielded functional fusion proteins in both Escherichia coli and B. japonicum. Expression of NolA is inducible upon addition of extracts from 5-day-old etiolated soybean seedlings but is not inducible by genistein, a known inducer of the B. japonicum nod genes. The expression of both NolA2 and NolA3 requires the presence of NolA1. NolA1 or NolA3 is required for the genotype-specific nodulation of soybean genotype PI 377578.

22q11 deletions in patients with conotruncal heart defects

OBJECTIVE

To ascertain the frequency of 22q11 deletions in a representative population of conotruncal heart defects (CTD) and determine which children are at risk of having a deletion.

METHODOLOGY

A clinical and laboratory evaluation of 90 children with CTD, including isolated and syndromic cases.

RESULTS

Fifteen children (17%) were shown to have 22q11 deletions by fluorescence in situ hybridization (FISH) studies with the Oncor probe N25. Varying degrees of developmental delay/learning disabilities and facial dysmorphism were common in these children. None of the isolated cases without dysmorphism had a deletion.

CONCLUSION

22q11 deletions are a significant cause of a specific form of congenital heart disease, CTD. It is important to have a high index of suspicion of the 22q11 deletion disorders in children with CTD and other extracardiac manifestations so that the diagnosis can be made early and appropriate interventions implemented.

Visualization of colorectal polyps with spiral CT colography: evaluation of processing parameters with perspective volume rendering

PURPOSE

To evaluate two key processing steps for detection of colon polyps with spiral computed tomographic (CT) colography with perspective volume rendering (PVR): image reconstruction and opacity assignment of the attenuation data.

MATERIALS AND METHODS

Spiral CT was performed in 10 patients with known polyps confirmed at colonoscopy, and detailed quantitative analyses were performed of data obtained in four. First, anatomic fidelity of three-dimensional (3D) images generated from two-dimensional (2D) source images with equal voxel dimensions (87%-90% overlap) was compared with 3D images generated from 2D source images with unequal voxel dimensions (0%-80% overlap). Next, the relative dimensions of colorectal polyps to adjacent structures were evaluated for various opacity threshold settings. Then, step and sigmoidal opacity functions were compared with respect to image smoothness and edge sharpness.

RESULTS

PVR images generated after interpolation of image data reconstructed with at least 60% overlap were equivalent in image quality to PVR images generated from source images with equal voxel dimensions. Relative polyp-to-haustral fold dimensions demonstrated substantial distortions with opacity thresholds below -700 HU. The 3D PVR images generated with the sigmoidal opacity function were significantly smoother than those generated with the step opacity function (paired t test, P < .02), with small differences noted in edge sharpness.

CONCLUSION

Use of highly overlapping source images (87%-90%) was not necessary to generate 3D PVR images of colorectal polyps. Image artifacts were suppressed with use of an appropriate opacity threshold and a sigmoidal opacity function without substantial loss in edge sharpness.

NodV and NodW, a second flavonoid recognition system regulating nod gene expression in Bradyrhizobium japonicum

In Bradyrhizobium japonicum, members of two global regulatory families, a LysR-type regulator, NodD1, and a two-component regulatory system, NodVW, positively regulate nod gene expression in response to plant-produced isoflavone signals. By analogy to other two-component systems, NodV and NodW are thought to activate transcription via a series of phosphorylation steps. These include the phosphorylation of NodV in response to the plant signal and the subsequent activation of NodW via the transfer of the phosphoryl group to an aspartate residue in the receiver domain of NodW. In this study, we demonstrated that NodW can be phosphorylated in vitro by both acetyl phosphate and its cognate kinase, NodV. In addition, in vivo experiments indicate that phosphorylation is induced by genistein, a known isoflavone nod gene inducer in B. japonicum. By using site-directed mutagenesis, a NodWD70N mutant in which the aspartate residue at the proposed phosphorylation site was converted to an asparagine residue was generated. This mutant was not phosphorylated in either in vitro or in vivo assays. Comparisons of the biological activity of both the wild-type and mutant proteins indicate that phosphorylation of NodW is essential for the ability of NodW to activate nod gene expression.

NodV and NodW, a second flavonoid recognition system regulating nod gene expression in Bradyrhizobium japonicum

In Bradyrhizobium japonicum, members of two global regulatory families, a LysR-type regulator, NodD1, and a two-component regulatory system, NodVW, positively regulate nod gene expression in response to plant-produced isoflavone signals. By analogy to other two-component systems, NodV and NodW are thought to activate transcription via a series of phosphorylation steps. These include the phosphorylation of NodV in response to the plant signal and the subsequent activation of NodW via the transfer of the phosphoryl group to an aspartate residue in the receiver domain of NodW. In this study, we demonstrated that NodW can be phosphorylated in vitro by both acetyl phosphate and its cognate kinase, NodV. In addition, in vivo experiments indicate that phosphorylation is induced by genistein, a known isoflavone nod gene inducer in B. japonicum. By using site-directed mutagenesis, a NodWD70N mutant in which the aspartate residue at the proposed phosphorylation site was converted to an asparagine residue was generated. This mutant was not phosphorylated in either in vitro or in vivo assays. Comparisons of the biological activity of both the wild-type and mutant proteins indicate that phosphorylation of NodW is essential for the ability of NodW to activate nod gene expression.

Phenotypic characterization and regulation of the nolA gene of Bradyrhizobium japonicum

Two Bradyrhizobium japonicum nolA mutants were constructed and used to test the functional role of NolA in nodulation. Contrary to the previous hypothesis that NolA acts as a repressor of nod gene transcription, the expression of a nodD1-lacZ or nodY-lacZ fusion in the nolA mutant strains was similar to that found in the wild type. However, NolA does appear to act as a transcriptional regulatory protein since it is required for its own expression, as well as that of nodD2. Expression of NodD2 from a constitutive promoter led to a significant reduction in nodC-lacZ activity. Therefore, the repression of nod gene expression by NolA is likely an indirect effect, perhaps mediated by other genes (e.g., nodD2) that are regulated by NolA. When inoculated onto soybean roots, the nolA mutant strains showed only a slight delay in nodulation as compared to the wild type. However, the mutant strains were grossly defective in nodulation and nitrogen fixation on cowpea plants. Microscopic examination of soybean nodules induced by the nolA mutant strains showed developmental and morphological characteristics similar to nodules formed by the wild type with only a slight delay in bacteroid maturation. In contrast, cowpea nodules induced by the nolA mutant strains contained fewer infected cells and bacteroids were not found in a typical symbiosome structure. These results indicate that NolA is a transcriptional activator required for the expression of genes that play a role not only in the early stages of infection, but also during the later stages of bacteroid development and maintenance.

Low-affinity antibodies against collagen type II produced by lymph node cells are associated with pathology in collagen-induced arthritis in rats

The relationship between the affinity of antibodies against type II collagen (CII) and arthritis was studied in rats immunized intradermally with bovine CII. Disease was associated with a higher mean titre of serum antibody and a lower mean functional antibody affinity (determined in a chaotropic dissociation assay) against both the immunizing bovine CII and homologous autoantigenic rat CII in comparison with the response in immunized rats that did not develop disease. The functional affinity of the antibodies present in the serum was found to correlate with that of antibodies produced in culture by cells from the lymph nodes draining the site of immunization with collagen. The reduction in mean functional affinity in the anti-collagen response may be the result of the increased production of antibodies of the lowest affinity and a consequent broadening of the affinity heterogeneity. It is proposed that production of low-affinity antibodies in the lymph nodes draining the site of immunization with collagen is important in the pathogenesis of collagen-induced arthritis in rats.

The predictive value of the time course of ST segment depression during exercise testing in patients referred for coronary angiograms

We studied the time course of ST segment depression during and after exercise testing in 462 subjects who also had coronary angiograms. Sixty-three percent of patients with late onset-early offset ST depression, previously reported to be likely to have false positive tests, had significant coronary artery disease, and 32% had three-vessel disease. Those with early onset and late offset ST depression and those with resting ST depression that was accentuated with exercise had a high prevalence of significant coronary artery disease and three-vessel disease. We found that observation of the time course of ST depression during and after exercise adds significantly to the information gained during exercise testing.

The autonomic orienting response and CT scan findings in schizophrenia

CT scan measures of prefrontal sulcal prominence, parieto-occipital sulcal prominence, ventricle-brain ratio (VBR), and third ventricle width (TVW) were examined in 24 schizophrenic patients who were grouped on the basis of their autonomic orienting response (OR) status. A two-component definition of the OR was used that required concordance across both electrodermal and finger pulse volume components for response status assignment. The nine OR responders had significantly greater TVW than the 15 OR nonresponders. Although OR responders had higher values also on the other CT scan measures, these differences were not significant. These findings are consistent with the possibility that OR responsiveness and nonresponsiveness are related to different pathological dimensions of schizophrenia.

The management of arterial injuries caused by penetration of zone III of the neck

Penetrating trauma of the neck has been divided into three anatomic locations. Zone III, the subject of this paper, is defined as the area between the base of the skull and the lower border of the mandible. Management of these injuries remains problematic. Clinical assessment may be misleading, exploration may damage surrounding neurovascular structures, and injuries may go undetected. This has led us and others to advocate mandatory angiography before any surgical exploration. This report reviews 46 patients with Zone III injuries with respect to types of injuries, therapy and outcome. Angiography was normal in 22 patients who were treated conservatively with no complications. The remaining 24 patients sustained 39 arterial injuries diagnosed by contrast studies. Eighteen internal carotid injuries were identified in 16 patients. At operation ligation was performed in four patients and revascularization in two patients. One of the repairs subsequently thrombosed. Ten patients were managed nonoperatively by observation (seven patients) or angiographic embolization (three patients). Catheter embolization of the external carotid or its branches was performed to control bleeding (eight vessels) or close arteriovenous fistulas (two patients). Seven nonbleeding external vessels were successfully managed by observation. Two vertebral artery injuries were diagnosed. One required proximal embolization and distal ligation via occipital craniectomy to control a fistula between the vertebral artery and the jugular vein. Overall mortality was 8.6%. Three of the four deaths were in patients with neurologic deficit on admission. Another died of respiratory arrest. An air embolism resulting in hemiparesis was the only complication of the angiographic studies. We conclude that angiography is essential in Zone III neck wounds. It facilitates triage decisions and, combined with transcatheter embolization, enables the majority of these injuries to be managed without surgical exploration.

Combined modality therapy for esophageal squamous cell carcinoma

Of 55 patients with esophageal squamous cell carcinoma, 30 with localized disease were treated with a combined modality for curative intent. Treatment consisted of mitomycin C (10 mg/m2 day 1) and continuous infusion 5-FU (1000 mg/m2 day, days 1-4, 29-32) (CT), radiation (XRT) (3000 rad, days 1-21) with nutritional support, and surgery (days 49-64). Surgery consisted of celiotomy, esophagectomy and esophagogastrostomy +/- postoperative ventilatory support. Postoperative CT plus an additional 2000 rad XRT was restricted to patients with histologic positive tumor. Since five resected patients with subclinical metastatic tumor had an inferior survival equal to 25 patients treated essentially for palliation, pretreatment celiotomy seems warranted to identify patients with an inferior prognosis. Of 18 resected patients without disseminated tumor evaluable for this combined modality: six were tumor free, three had intramural and nine transmural tumor; the median survival is 76 weeks and five of six living patients are disease free at 95-190 weeks; and local recurrence occurred in two and in two of seven unresected patients. Since toxicity was minimal except for postoperative pneumonitis (13%) and local recurrence low (13%), two courses of chemotherapy and 5000 rad XRT perhaps obviates the need for resection.

Clinical trial of cisplatin and 5-FU infusion as initial treatment for advanced squamous cell carcinoma of the head and neck

Initial treatment with drug combinations that include cisplatin and bleomycin has been effective in reducing tumor in patients with previously untreated epidermoid cancers of the head and neck. Because of the threat of pulmonary complications from bleomycin, patients with poor pulmonary function were excluded from those studies. We conducted a trial using the combination of cisplatin (100 mg/m2) and a 96-hour infusion of 5-FU (1000 mg/m2/day) and achieved a response rate of 88.5% in 26 patients treated with two courses. Five of these patients had complete remissions and 18 had partial remissions. Nausea and vomiting (experienced by 70% of the patients) was the predominant toxic effect, and 26% experienced leukopenia. Although all patients were initially inoperable, six underwent resection following chemotherapy, and another six underwent resection after chemotherapy and irradiation. Two additional patients were treated with radiation therapy after clinically achieving complete remissions following chemotherapy, and another ten received X-ray therapy after chemotherapy. Cisplatin and 5-FU infusion are effective without being as toxic as bleomycin in patients with previously untreated advanced carcinoma of the head and neck.

Cryptorchidism and testicular cancer

An analysis of 125 patients with a history or clinical evidence of cryptorchidism and testicular germinal tumor treated at our hospital from 1934 to 1975 is presented. Cryptorchidism was corrected ipsilaterally or contralaterally in 83 patients with intrascrotal testis cancer when they were from 4 to 42 years old, either spontaneously (21 patients), by orchiopexy (51 patients) or by hormonal therapy (11 patients). Forty-two cryptorchid patients (uncorrected cases) presented with either ipsilateral inguinal (24 patients), abdominal (14 patients) or contralateral intrascrotal tumors (4 patients). Tumor histologic types on orchiectomy were pure seminoma in 54 patients, embryonal carcinoma in 35, teratocarcinoma in 33 and pure choriocarcinoma in 3. The 5-year survival rates were 60 per cent for the corrected cases and 63 per cent for the uncorrected cases according to cryptorchid state, and they were 78 per cent in patients with pure seminoma and 48 per cent in patients with other germinomas according to histologic type. The majority (58 of 73) of 5-year survivors received regional lymphatic irradiation, in 39 patients with pure seminoma, and/or systemic chemotherapy, in 19 patients with germinal carcinomas, with or without regional lymphadenectomy.