The Chlamydomonas reinhardtii chloroplast envelope protein LCIA transports bicarbonate in planta

LCIA is a chloroplast envelope protein associated with the CO2 concentrating mechanism of the green alga Chlamydomonas reinhardtii. LCIA is postulated to be a HCO3- channel, but previous studies were unable to show that LCIA was actively transporting bicarbonate in planta. Therefore, LCIA activity was investigated more directly in two heterologous systems: an E. coli mutant (DCAKO) lacking both native carbonic anhydrases and an Arabidopsis mutant (βca5) missing the plastid carbonic anhydrase βCA5. Both DCAKO and βca5 cannot grow in ambient CO2 conditions, as they lack carbonic anhydrase-catalyzed production of the necessary HCO3- concentration for lipid and nucleic acid biosynthesis. Expression of LCIA restored growth in both systems in ambient CO2 conditions, which strongly suggests that LCIA is facilitating HCO3- uptake in each system. To our knowledge, this is the first direct evidence that LCIA moves HCO3- across membranes in bacteria and plants. Furthermore, the βca5 plant bioassay used in this study is the first system for testing HCO3- transport activity in planta, an experimental breakthrough that will be valuable for future studies aimed at improving the photosynthetic efficiency of crop plants using components from algal CO2 concentrating mechanisms.

AB1092 INFLAMMATORY ARTHRITIDES IN POST-COVID-19 PATIENTS: AN ALBANIAN EXPERIENCE

Background

COVID-19 is a disease caused by the new pathogen SARS-CoV2 (severe acute respiratory syndrome coronavirus 2) typically presenting with pneumonia but also other systemic manifestation has been reported worldwide [1]. Different reports have described the appearance of inflammatory arthritis (IA) after resolution of acute infection from COVID-19 [2].

Objectives

To observe the frequency of Inflammatory Arthritis in an Albanian cohort of post-COVID-19 patients.

Methods

Post-Covid-19 patients, having two consecutive negative PCR (real-time reverse transcription polymerase chain reaction), discharged from the Pulmonology Department (January – July 2021) were invited to enter in a 6 (six) month multidisciplinary observational study. Data regarding post-COVID-19 inflammatory arthritis are presented in this study. Descriptive statistical analysis was used to express data.

Results

From 154 post-COVID-19 patients (F/M = 62/92) enrolled, 14 (9.09%) patients didn’t follow regularly the dedicated ambulatory thus were excluded from this study. Considering the remaining 140 patients (F/M = 58/82), only 21 (15%) patients were diagnosed with IA where the most common were, respectively: Reactive Arthritis (ReA) 11 (52.3%) patients; Rheumatoid Arthritis (RA) 4 (19.09%) patients; Ankylosing Spondylitis (AS) 3 (14.2%) patients; Gout Arthritis (GA) 3 (14.2%) patients. All rheumatic conditions were more frequent in male than in female post-COVID-19 patients. Data summarized in Table 1. All patients that developed a post COVID-19 IA, had fever during the period of SARS-CoV2 infection. Arthralgia was a typical symptom that have been reported by patients that have developed RA and AS. All RA post-Covid-19 patients reported having had even symptoms like cough, dispnea and fatigue. None of the AS patients neither GA reported symptoms of dysguesia or anosmia. Only 9% of ReA patients reported having had abdominal pain during acute infection with SARS-Cov2. Data summarized in Figure 1.

Table 1.Inflammatory ArthritisPatients (N, %)Age (mean ± SD)Male (N, %)Days after COVID-19 (mean ± SD)ReA11 (52.3)48.2 ± 12.57 (63.6)15.8 ± 9.9RA4 (19,09)55.7 ± 8.72 (50)32.3 ± 11.3AS3 (14.2)50.5 ± 9.72 (14.2)18.8 ± 5.5GA3 (14.2)55.3 ± 1.23 (100)10.6 ± 0.9

Conclusion

IA is another manifestation that follows acute infection from COVID-19. In this regard increased awareness and further investigations are needed in order to better understand weather SARS-Cov2 infection can accelerate the development of a rheumatic autoimmune disease.

References

[1]Mahajan RK, Paul G, Mahajan R, Gautam PL, Paul B. Systemic manifestations of COVID-19. J Anaesthesiol Clin Pharmacol. 2020; 36 (4):435-442.

[2]Zacharias H, Dubey S, Koduri G, D’Cruz D. Rheumatological complications of Covid 19. Autoimmun Rev. 2021; 20 (9):102883.

Disclosure of Interests

None declared

Expression of a CO2-permeable aquaporin enhances mesophyll conductance in the C4 species Setaria viridis

A fundamental limitation of photosynthetic carbon fixation is the availability of CO₂. In C₄ plants, primary carboxylation occurs in mesophyll cytosol, and little is known about the role of CO₂ diffusion in facilitating C₄ photosynthesis. We have examined the expression, localization, and functional role of selected plasma membrane intrinsic aquaporins (PIPs) from Setaria italica (foxtail millet) and discovered that SiPIP2;7 is CO₂-permeable. When ectopically expressed in mesophyll cells of Setaria viridis (green foxtail), SiPIP2;7 was localized to the plasma membrane and caused no marked changes in leaf biochemistry. Gas exchange and C¹⁸O¹⁶O discrimination measurements revealed that targeted expression of SiPIP2;7 enhanced the conductance to CO₂ diffusion from the intercellular airspace to the mesophyll cytosol. Our results demonstrate that mesophyll conductance limits C₄ photosynthesis at low pCO₂ and that SiPIP2;7 is a functional CO₂ permeable aquaporin that can improve CO₂ diffusion at the airspace/mesophyll interface and enhance C₄ photosynthesis.

A low CO2-responsive mutant of Setaria viridis reveals that reduced carbonic anhydrase limits C4 photosynthesis

In C4 species, β-carbonic anhydrase (CA), localized to the cytosol of the mesophyll cells, accelerates the interconversion of CO2 to HCO3-, the substrate used by phosphoenolpyruvate carboxylase (PEPC) in the first step of C4 photosynthesis. Here we describe the identification and characterization of low CO2-responsive mutant 1 (lcr1) isolated from an N-nitroso-N-methylurea- (NMU) treated Setaria viridis mutant population. Forward genetic investigation revealed that the mutated gene Sevir.5G247800 of lcr1 possessed a single nucleotide transition from cytosine to thymine in a β-CA gene causing an amino acid change from leucine to phenylalanine. This resulted in severe reduction in growth and photosynthesis in the mutant. Both the CO2 compensation point and carbon isotope discrimination values of the mutant were significantly increased. Growth of the mutants was stunted when grown under ambient pCO2 but recovered at elevated pCO2. Further bioinformatics analyses revealed that the mutation has led to functional changes in one of the conserved residues of the protein, situated near the catalytic site. CA transcript accumulation in the mutant was 80% lower, CA protein accumulation 30% lower, and CA activity ~98% lower compared with the wild type. Changes in the abundance of other primary C4 pathway enzymes were observed; accumulation of PEPC protein was significantly increased and accumulation of malate dehydrogenase and malic enzyme decreased. The reduction of CA protein activity and abundance in lcr1 restricts the supply of bicarbonate to PEPC, limiting C4 photosynthesis and growth. This study establishes Sevir.5G247800 as the major CA allele in Setaria for C4 photosynthesis and provides important insights into the function of CA in C4 photosynthesis that would be required to generate a rice plant with a functional C4 biochemical pathway.

Bundle sheath suberisation is required for C4 photosynthesis in a Setaria viridis mutant

C4 photosynthesis provides an effective solution for overcoming the catalytic inefficiency of Rubisco. The pathway is characterised by a biochemical CO2 concentrating mechanism that operates across mesophyll and bundle sheath (BS) cells and relies on a gas tight BS compartment. A screen of a mutant population of Setaria viridis, an NADP-malic enzyme type C4 monocot, generated using N-nitroso-N-methylurea identified a mutant with an amino acid change in the gene coding region of the ABCG transporter, a step in the suberin synthesis pathway. Here, Nile red staining, TEM, and GC/MS confirmed the alteration in suberin deposition in the BS cell wall of the mutant. We show that this has disrupted the suberin lamellae of BS cell wall and increased BS conductance to CO2 diffusion more than two-fold in the mutant. Consequently, BS CO2 partial pressure is reduced and CO2 assimilation was impaired in the mutant. Our findings provide experimental evidence that a functional suberin lamellae is an essential anatomical feature for efficient C4 photosynthesis in NADP-ME plants like S. viridis and have implications for engineering strategies to ensure future food security.

Aloe vera modulates X-ray induced hematological and splenic tissue damage in mice

The present study was premeditated to examine the radioprotective effects of aqueous Aloe vera gel extract against whole-body X-ray irradiation-induced hematological alterations and splenic tissue injury in mice. Healthy male balb/c mice were divided into four groups: group 1, control; group 2, A. vera (50 mg/kg body weight) administered per oral on alternate days for 30 days (15 times); group 3, X-ray exposure of 2 Gy (0.25 Gy twice a day for four consecutive days in the last week of the experimental protocol); and group 4, A. vera + X-ray. X-ray exposure caused alterations in histoarchitecture of spleen along with enhanced clastogenic damage as assessed by micronucleus formation and apoptotic index. Irradiation caused an elevation in proinflammatory cytokines like tumor necrosis factor and interleukin-6, total leucocyte counts, neutrophil counts and decreased platelet counts along with unaltered red blood cell counts and hemoglobin. Irradiation also caused an elevation in reactive oxygen species (ROS), lipid peroxidation (LPO) levels, lactate dehydrogenase activity and alterations in enzymatic and nonenzymatic antioxidant defense mechanism in plasma and spleen. However, administration of A. vera gel extract ameliorated X-ray irradiation-induced elevation in ROS/LPO levels, histopathological and clastogenic damage. It also modulated biochemical indices, inflammatory markers, and hematological parameters. These results collectively indicated that the A. vera gel extract offers protection against whole-body X-ray exposure by virtue of its antioxidant, anti-inflammatory and anti-apoptotic potential.

Carboxysome encapsulation of the CO2-fixing enzyme Rubisco in tobacco chloroplasts

A long-term strategy to enhance global crop photosynthesis and yield involves the introduction of cyanobacterial CO2-concentrating mechanisms (CCMs) into plant chloroplasts. Cyanobacterial CCMs enable relatively rapid CO2 fixation by elevating intracellular inorganic carbon as bicarbonate, then concentrating it as CO2 around the enzyme Rubisco in specialized protein micro-compartments called carboxysomes. To date, chloroplastic expression of carboxysomes has been elusive, requiring coordinated expression of almost a dozen proteins. Here we successfully produce simplified carboxysomes, isometric with those of the source organism Cyanobium, within tobacco chloroplasts. We replace the endogenous Rubisco large subunit gene with cyanobacterial Form-1A Rubisco large and small subunit genes, along with genes for two key α-carboxysome structural proteins. This minimal gene set produces carboxysomes, which encapsulate the introduced Rubisco and enable autotrophic growth at elevated CO2. This result demonstrates the formation of α-carboxysomes from a reduced gene set, informing the step-wise construction of fully functional α-carboxysomes in chloroplasts.

Pulmonary Rehabilitation - PR

Chronic respiratory diseases are associated with severe, not only pulmonary, but also systemic damage such as dysfunction of peripheral muscles, dysfunction of respiratory muscles, nutritional disorders, cardiac injuries, skeletal disorders, sensory debilities, and psychological dysfunction. Mechanisms of these injuries are many and different. Pulmonary recovery (PR) is an integral part of clinical therapy in patients with chronic respiratory disease who continue to be symptomatic or continue to have pulmonary function depression, regardless of standard medical treatment.  

Protective role of Aloe vera against X-ray induced testicular dysfunction

The present investigation was carried out to evaluate the possible radioprotective potential of an Aloe vera extract against whole-body X-ray irradiation-induced testicular alterations in mice. Male balb/c mice were divided into four groups: control, A. vera, X-ray and A. vera pre-treated + X-ray irradiated. Histopathological examination revealed significant structural alterations in testes after X-ray exposure, which was also associated with the presence of apoptotic cells as assessed by TUNEL assay. X-ray irradiation resulted in elevation in the levels of reactive oxygen species, lipid peroxidation, a reduction in glutathione concentration and enhanced activities of antioxidant enzymes such as glutathione reductase, glutathione peroxidase, catalase, superoxide dismutase and glutathione-S-transferase. Sperm count/motility and testosterone levels were significantly decreased in the irradiated group. Irradiated animals pre-treated with A. vera extract revealed an improvement in antioxidant status, inhibition of lipid peroxides, apoptotic cell formation and enhanced testicular parameters when compared to the X-ray-exposed group. These findings suggest that A. vera extract could ameliorate X-ray-induced damage due to its free radical scavenging properties and its potential to boost cellular antioxidant defence machinery.

Unmasking of primary hyperparathyroidism by Vitamin D therapy

A 38-year-old female on Vitamin D therapy presented with hypercalcemia induced acute kidney injury. Evaluation revealed primary hyperparathyroidism (PHPT) and iatrogenic hypervitaminosis D. After medical stabilization, she underwent surgical removal of the parathyroid adenoma, and made a full recovery. This case highlights unmasking of subclinical hyperparathyroidism by vitamin D therapy leading to severe hypercalcemia.

EFFECT OF TOPICAL APPLICATION OF MEDICINAL GRADE PETROLATUM ON VARIOUS SPECIES OF LABORATORY ANIMALS AND MAN

Medicinal grade yellow and white petrolatum (soft paraffin) were tested for dermatoxic effects on laboratory animals and man. Yellow petrolatum produced redness, thickening of skin, hyperkeratosis and reversible total hair loss in rabbit and rat but no dermatoxic effect was observed in man and dog. White petrolatum which is similar in composition to yellow petrolatum produced less redness and keratosis. Refluxing of yellow soft paraffin with 95% alcohol could dissolve out dermatoxic fraction. The results have been discussed and it is suggested that drugs with petrolatum as ointment base should not be tested on rats and rabbits as petrolatum itself is dermatoxic in these species.

Regenerative endodontic treatment of an immature tooth with a necrotic pulp and apical periodontitis using platelet-rich plasma (PRP) and mineral trioxide aggregate (MTA): a case report

AIM

To report the successful clinical and radiographic outcome of a regenerative endodontic treatment.

SUMMARY

A 16-year-old male patient presented with a discoloured, maxillary left lateral incisor with a necrotic pulp. Radiographic examination revealed an incompletely developed root with an open apex. Under local anaesthesia and rubber dam isolation, an access cavity was prepared and the necrotic pulpal remnants were removed. The canal was disinfected without mechanical instrumentation with 5.25% NaOCl solution and dried with sterile paper points. A triple antibiotic (metronidazole, ciprofloxacin and minocycline) mixed with distilled water was packed in the canal and left for 28 days. Ten millimetres of whole blood was drawn by venipuncture from the patients antecubital vein for preparation of platelet-rich plasma (PRP). After removal of the antibiotic mixture, the PRP was injected into the canal space up to the cementoenamel junction level. Three millimetres of white MTA was placed directly over the PRP clot. Two days later, the tooth was restored with permanent filling materials. The patient was recalled for 3, 6, 12, 24 and 36 months clinical/radiographic follow-up. A 3-year follow-up radiograph revealed resolution of the periapical lesion, increased thickening of the root walls, further root development and continued apical closure of the root apex. The tooth was not responsive to cold tests; however, sensitivity tests with an electric pulp tester (EPT) elicited a delayed positive response.

KEY LEARNING POINTS

Regeneration is a viable treatment modality that allows continued root development of immature teeth with open apices and necrotic pulps. Platelet-rich plasma appears to be a suitable scaffold for regeneration of vital tissues in teeth with a necrotic pulps and an associated periapical lesion. Regenerative endodontic procedures may offer an effective treatment option to save teeth with compromised structural integrity.

Supply chain and marketing of sea grapes, Caulerpa racemosa (Forsskål) J. Agardh (Chlorophyta: Caulerpaceae) in Fiji, Samoa and Tonga

This report describes for the first time the supply chain of Caulerpa racemosa in three Pacific Island countries. The harvesting and marketing of C. racemosa are important subsistence activities for villagers in Fiji and Samoa, less so in Tonga. At least 150 harvesters are involved in Fiji, some 100 in Samoa and only a handful in Tonga. The annual combined crop is of some 123 t valued at around US$266,492. In Fiji, it is projected that supply does not meet local demand and there is a potential export market that is currently operating at a pilot project level. In Samoa, the supply is considered adequate for the current market. In Tonga, harvesting is carried out by a few families and supplies a niche market in that country. The possibilities of field cultivation of Caulerpa have been explored but, at present, with only limited success in Samoa. The supply chain is simple in all three countries, and only in Fiji are middlemen involved in the distribution process. The limitations for marketing include the fact that only a few sites supply most of the crop in all the three countries, that all sites need to be conserved through sustainable harvesting methods, the short shelf life of the crop and a lack of information on the carrying capacity of harvest sites. Caulerpa remains a crop that fulfils a niche market but has the potential to be scaled up for additional livelihood development in the future.

Abstract P4-01-09: 18F-FLT-PET/CT for the prediction of response to ANG-1005 therapy in patients with brain metastases from breast cancer

Background: ANG1005 (formerly called GRN1005) is a peptide-drug conjugate being developed for targeted treatment of brain metastases. It consists of 3 molecules of paclitaxel covalently linked to Angiopep-2 designed to cross the blood brain barrier (BBB) via the low density lipoprotein (LDL) receptor-related protein-1 (LRP1)-mediated trancytosis. This drug was evaluated in a multi-center, open-label single-arm study (GRABMB study). An interim analysis determined that the agent met the futility endpoint based on MRI assessment (SABC 2012). However, centrally confirmed responses were achieved in the study, and a biomarker substudy enrolling patients (pts) to evaluate the utility of FLT-PET in assessing response to treatment with ANG1005 suggested sufficient activity of the agent to allow continuation of the study. 18F-FLT (3’-Fluoro-3’ deoxythymidine)-PET imaging is a novel imaging modality which provides a tool for measuring in vivo tumor cell proliferation. FLT is an analog of thymidine; cellular retention of FLT reflects DNA synthesis.

Methods: Adult pts with measurable BMBC were eligible with or without history of prior WBRT. We compared 18F-FLT-PET/CT with MRI-gadolinium contrast images for brain metastases detection and for assessment of whether treatment with ANG1005 was associated with significant change in intracranial tumor uptake of 18F-FLT.

ANG1005 therapy was administered intravenously at 550 mg/m2 q 21d until progression of intra-cranial disease or unacceptable toxicity. All pts underwent 18F-FLT PET/CT imaging before and after 1 cycle of therapy with ANG1005. Pts were scanned dynamically over 30 min followed by a static whole body PET image at 1 hour post-injection. We calculated the% of change before and after therapy, with change > 20% considered significant.

Results: 5/10 planned pts have been accrued to the substudy to date, and 12 metastatic brain lesions have been analyzed. The maximum standard uptake value (SUVmax) ranged from 0.8 to 4.0, mean 1.8 for baseline scans. Tumor to normal brain background ratios ranged from 3.2 to 22.3, mean 9.4. 7/12 lesions showed >20% change between pre and post therapy. The average% change was (-) 42.39% ± 12.77, range: 29.2 to 66.8% (using SUVmax), and (-) 38.7% ± 14.3, range: 20.12 to 57.10% (using tumor to normal ratios). Based on brain MRI evaluation per RECIST 1.1 criteria, 1 pt had intra-cranial partial response (PR) and 3 patients had stable disease (SD). These pts remained on therapy for an average of 7 cycles, range: 5 to 9 cycles. 1 pt withdrew consent after 2 cycles of therapy and opted to receive whole brain radiation therapy. 5/42 pts achieved a confirmed investigator-assessed PR by MRI at 550 mg/m2, and 4/13 pts achieved a PR at 650 mg/m2, a dose not progressed due to toxicity.

Conclusion: This pilot study using 18F-FLT-PET imaging of brain metastases suggests that it is a promising tool for detection and measurement of CNS disease. Given that contrast-enhanced MRI detection of brain metastases represent gadolinium leakage through the BBB rather than actual tumor volume measurements, better approaches are needed to assess efficacy of therapies. Accrual to this study is ongoing. Updated results with ANG1005 will be presented during the meeting.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-01-09.

Summary of FDA workshop on ischemia reperfusion injury in kidney transplantation

The Food and Drug Administration (FDA) held an open public workshop in September 2011 to discuss the current state of science related to the effects of ischemia reperfusion injury (IRI) on outcomes in kidney transplantation. Topics included the development of IRI and delayed graft function (DGF), histology and biomarkers, donor factors, recipient factors, organ quality and organ preservation by means of cold storage solutions or machine perfusion. Various mechanisms of injury and maladaptive response to IRI were discussed as potential targets of intervention. Animal models evaluating specific pathophysiological pathways were presented, as were the limitations of extrapolating animal results to humans. Clinical trials of various drug products administered in the peri-transplant period were summarized; a few demonstrated early improvements in DGF, but none demonstrated an improvement in late graft function. Clinical trial design for IRI and DGF were also discussed.

Functional analysis of corn husk photosynthesis

The husk surrounding the ear of corn/maize (Zea mays) has widely spaced veins with a number of interveinal mesophyll (M) cells and has been described as operating a partial C(3) photosynthetic pathway, in contrast to its leaves, which use the C(4) photosynthetic pathway. Here, we characterized photosynthesis in maize husk and leaf by measuring combined gas exchange and carbon isotope discrimination, the oxygen dependence of the CO(2) compensation point, and photosynthetic enzyme activity and localization together with anatomy. The CO(2) assimilation rate in the husk was less than that in the leaves and did not saturate at high CO(2), indicating CO(2) diffusion limitations. However, maximal photosynthetic rates were similar between the leaf and husk when expressed on a chlorophyll basis. The CO(2) compensation points of the husk were high compared with the leaf but did not vary with oxygen concentration. This and the low carbon isotope discrimination measured concurrently with gas exchange in the husk and leaf suggested C(4)-like photosynthesis in the husk. However, both Rubisco activity and the ratio of phosphoenolpyruvate carboxylase to Rubisco activity were reduced in the husk. Immunolocalization studies showed that phosphoenolpyruvate carboxylase is specifically localized in the layer of M cells surrounding the bundle sheath cells, while Rubisco and glycine decarboxylase were enriched in bundle sheath cells but also present in M cells. We conclude that maize husk operates C(4) photosynthesis dispersed around the widely spaced veins (analogous to leaves) in a diffusion-limited manner due to low M surface area exposed to intercellular air space, with the functional role of Rubisco and glycine decarboxylase in distant M yet to be explained.

Summary of FDA antibody-mediated rejection workshop

The Food and Drug Administration (FDA) held an open public workshop in June 2010 to discuss the current state of science related to antibody-mediated rejection (AMR) in kidney transplantation. Desensitization, acute AMR and chronic AMR (CAMR) were considered in the context of clinical trial design. Participants discussed experiences with HLA antibody detection and quantitation and the utility of monitoring donor-specific antibodies (DSAs) to inform the management of patients with AMR. The role for animal models was discussed. Diagnostic and prognostic features of histology were presented, followed by discussion of sensitivity and specificity of various criteria. The published literature on treatment of acute AMR was summarized, which consisted of case series and limited data from controlled clinical trials. Considerations for future clinical trials were presented, including endpoints and statistical evaluations of outcome. Although many issues need further consideration, the meeting enabled an important exchange of ideas between experts in the field.

Intraorbital organic foreign body--a diagnostic challenge

Intraorbital organic foreign bodies pose a diagnostic and management challenge to ophthalmologists. A high degree of suspicion of an orbital foreign body is needed when patients present with injuries to the eyelids and orbit. We present a case of retained intraorbital wooden foreign body which was initially undetected. A 10-year-old boy presented to the eye casualty with signs and symptoms suggestive of orbital cellulitis. He was started on intravenous antibiotics and urgent CT of the orbits did not reveal any foreign bodies. There was spontaneous extrusion of a wooden foreign body through the upper lid two days later, followed by spontaneous resolution of symptoms. Wood has a density similar to air and fat and can be difficult to distinguish from soft tissue in both a plain X-ray film and a computed tomogram. Clinicians should be alerted to the possibility of retention of an intraorbital foreign body in all patients presenting with periorbital trauma. The clinician should also obtain a careful history of the type of injury and should examine the patient in detail. In cases where a wooden foreign body is suspected, investigation by magnetic resonance imaging is preferred.

Lipid-laden macrophage index in healthy canines

BACKGROUND

The quantity of lipids in alveolar macrophages is used clinically as an indicator of aspiration, which is associated with increased lung inflammation. This is determined in the macrophages obtained from bronchoalveolar lavage (BAL) and is expressed as lipid-laden macrophage index (LLMI). Although there is ample data on LLMI in human subjects, there is no published data pertaining to the baseline measures of the LLMI in canines, which are extensively used for experimental studies on gastroesophageal reflex (GER) and airway diseases. Primary aim of the present study was to collect data pertaining to the cytology and LLMI in BAL fluids obtained from healthy dogs.

MATERIALS AND METHODS

Eight dogs underwent a bronchoscopy with BAL collection, and esophageal pH monitoring to determine the reflux index (RI). The BAL fluid was processed and reviewed under a microscope to determine the proportions of the various cell types and the LLMI.

RESULTS

The median RI among the subjects was found to be 0.6 (0.0, 1.2). The BAL cytology analysis showed 77.5% (71.0, 83.5) macrophages, 21.0 (13.0, 24.5) lymphocytes and 2.5 (1.5, 5.0) neutrophils. The median LLMI was found to be 156 (111, 208).

CONCLUSIONS

Although the differential cell counts in the dogs' BAL fluid was comparable to that of other experimental animals and humans, the LLMI was distinctly higher than the corresponding value reported for other species. As LLMI is a valuable modality for evaluation of intrapulmonary pathophysiology, these data on LLMI can be used as a species-specific standard for canine subjects used for experimental studies on GER and airway diseases.

CYCLIN D1 as a genetic modifier in hereditary nonpolyposis colorectal cancer

Hereditary nonpolyposis colorectal cancer is associated with inherited defects in DNA mismatch repair. Clinical variation even in cases with identical predisposing mutations suggests the existence of other factors contributing to the phenotype. We addressed the modifying role of the common A/G polymorphism in exon 4 and the alternatively spliced transcripts a and b of the CCND1 gene encoding cyclin D1 in a series of 146 affected carriers of 10 MLH1 and 3 MSH2 mutations. No correlation was observed between a particular allele (A versus G) and age at onset. However, the presence of the variant transcript b in blood/normal mucosa, by multiplex reverse transcription-PCR, was associated with a significantly lower age at onset of colon cancer as compared with individuals with transcript a only (35 versus 46 years; P = 0.02). Whereas our data do not support a modifying role of A versus G allele of CCND1, the results do suggest that the relative abundance of a and b transcripts may modify the age at onset of colon cancer in hereditary nonpolyposis colorectal cancer.

Divergent structure and function of the bicoid gene in Muscoidea fly species

We have investigated the evolution of the bicoid (bcd) gene in fly species of the Muscoidea Superfamily. We obtained the complete bcd sequence from the housefly Musca domestica and found polymorphism in the coding region among Musca strains. In addition to Musca, we cloned most of the bcd coding sequences from two blowfly species Calliphora vicina and Lucilia sericata. The 5' and 3' regulatory regions flanking the Musca bcd gene are widely diverged in sequence from Drosophila; however, some important sequence motifs identified in Drosophila bcd are present. The predicted RNA secondary structures of the 3' UTRs are similar, despite sequence divergence. Comparison of Bicoid (Bcd) proteins shows a serine-rich domain of unknown function is present in the Muscoidea species, but is absent in other species. The in vivo function of bcd in Musca was tested by RNAi to mimic loss of function phenotype. We obtained a head defect phenotype similar to weak bcd alleles of Drosophila. Although our comparisons initially suggest functional conservation between species, closer inspection reveals significant differences. Divergence of structural motifs, such as regulatory elements in flanking regions and conservation of protein domains in some species but not in others, points to functional divergence between species. We suggest that the larger embryonic size in Muscoidea species restricts the morphogenetic activity of a weak Bcd activator, which has evolved a more specialized role in head determination and lost some functions in thoracic development.

An improved method for the analysis of sennosides in Cassia angustifolia by high-performance liquid chromatography

A reversed-phase column liquid chromatographic method for the analysis of sennosides A and B present in leaf and pod extracts of Cassia angustifolia has been developed using a Symmetry C18 column and a linear binary gradient profile. The method can be utilised for the quantitative determination of other sennosides as a baseline resolution for most of the constituents was achieved. The method is economical in terms of the time taken and the amount of solvent used (25 mL) for each analysis. The validity of the method with respect to analysis was confirmed by comparing the UV spectra of each peak with those of reference compounds using a photodiode array detector.

Symmetry C18 column: a better choice for the analysis of indole alkaloids of Catharanthus roseus

By virtue of the different elution patterns of vindoline, catharanthine, vincristine and vinblastine present in the leaves of Catharanthus roseus plants, a Symmetry C18 column provided a better resolution for all of these compounds as compared with other C18 columns. The binary gradient system with a linear gradient profile, employed in a method developed using a Symmetry C18 column, gave excellent peak symmetry, resolution and reproducibility. Detection was performed at 220 nm which presented better absorptivity for these indole alkaloids giving a minimum detection limit of 0.5 microgram. Photodiode array detection was used to determine the homogeneity and purity of each compound. The described analysis is rapid and economical to perform as small amounts of solvent are consumed per analysis, and the method will find application where a large number of samples are to be analysed as, for example, in crop improvement studies where plants need to be selected regularly on the basis of alkaloid production.

Effect of phloretin on ionophore mediated electroneutral transmembrane translocations of H(+), K(+) and Na(+) in phospholipid vesicles

Rates of M(+)/H(+) exchange (M(+)=K(+), Na(+)) across phospholipid membranes by ionophore mediated electroneutral translocations and transports through channels could either increase or decrease or change negligibly on adding the polar molecule phloretin to the membrane. The changes depend on pH, the concentration and choice of M(+) and choice of ionophore/channel. Such diverse behaviours have been inferred from studies on the decay of the pH difference across soybean phospholipid vesicular membrane (=Delta pH). The transporters used in this study are (a) the exchange ionophores: nigericin, monensin; (b) combinations of alkali metal ion carriers, valinomycin or nonactin with weak acids carbonyl cyanide m-chlorophenylhydrazone or 2,4-dinitrophenol and (c) channels formed by gramicidin A. All the diverse results can be rationally explained if we take note of the following. (i) The rate limiting steps are associated with the transmembrane translocations involving the rate limiting species identified in the literature. (ii) Phloretin in the membrane decreases the apparent M(+) dissociation constant, K(M), of the M(+) bound ionophores/channels which has the effect of increasing the concentration of these species. (iii) The concentrations of H(+) bound ionophores/channels decrease on adding phloretin. (iv) Phloretin inhibits ternary complex formation (involving valinomycin or nonactin, M(+) and an anion) by forming 1:2 complexes with valinomycin-M(+) or nonactin-M(+). (v) On adding 6-ketocholestanol to the membrane (instead of phloretin) K(M) increases. The decreases/increases in K(M) mentioned above are consistent with the consequences of a hypothesis in which phloretin decreases and 6-ketocholestanol increases the positive internal membrane dipole potential.

Genetic analysis of the APAF1 gene in male germ cell tumors

Cytogenetic and molecular analyses have shown that the chromosome band 12q22 is recurrently deleted in male germ cell tumors (GCTs), indicating the presence of a candidate tumor suppressor gene (TSG) in this region. To identify the TSG, we mapped the APAF1 gene, a proapoptotic mammalian homologue of ced-4, to chromosomal band 12q22, that suggested that this might be the candidate deleted gene in GCTs. We further localized the gene between the polymorphic markers D12S1671 and D12S1082 at 12q22 to determine the role of APAF1 in the pathogenesis of GCT, and we characterized its normal genomic structure and analyzed its alterations in GCTs. The APAF1 gene comprises 27 exons, with the coding region spanning 26. The region containing APAF1 was found to be deleted in GCT by fluorescence in situ hybridization analysis, but without evidence of coding sequence alterations. RT-PCR and Western blot analysis showed APAF1 gene expression at detectable levels in all GCT cell lines analyzed. An aberrant-sized APAF1 protein was seen in one cell line. This and 2 other cell lines carrying APAF1 deletions also exhibited defects in dATP-mediated caspase-3 activation. Caspase-3 activity was effectively restored by addition of recombinant caspase-9 and APAF1 proteins, and to a lesser extent by caspase-9 alone, but not by APAF1 alone. These data do not support a TSG role for APAF1, but defects in other components of the apoptotic pathway that may be related to 12q22 deletion cannot be ruled out. Genes Chromosomes Cancer 28:258-268, 2000.

Constitutive APC exon 14 skipping in early-onset familial adenomatous polyposis reveals a dramatic quantitative distortion of APC gene-specific isoforms

Adenomatous polyposis coli (APC) gene transcripts skipping exon 14 in combination with the alternatively spliced exons 9 and 10A contribute to the heterogeneity of physiological APC mRNA isoforms. Here we report on a novel genotype-phenotype correlation in familial adenomatous polyposis (FAP) with early onset of disease and malignancy due to an APC exon 14 splice defect. Compared to controls, two affected individuals of a FAP kindred presented with a significantly distorted APC mRNA isoform pattern in B lymphocytes. As a result of an A-->G transition in the canonical AG-splice acceptor dinucleotide of exon 14, expression levels of all APC mRNA isoforms without exon 14 were dramatically increased and those with exon 14 were simultaneously decreased. Skipping of exon 14 is a physiological event also seen in nonmalignant cells, which results in a frameshift to produce low-molecular-weight APC proteins. Western blot analysis of the patients' lymphoblastoid B cells revealed the identification of intracellularly stable APC protein isoforms with an Mr of 55-67 kDa and, thus, the first demonstration of APC proteins encoded by exon 14-skipped transcripts. We postulate that the quantitatively imbalanced expression of these physiological APC light chains represents a novel pathogenetic mechanism associated with predisposition to FAP.

Analysis of taxol and major taxoids in Himalayan yew, Taxus wallichiana

A reversed-phase column liquid chromatography method for the analysis of taxol, 10-deacetylbaccatin III, baccatin IV, 1-hydroxybaccatin I, 2-acetoxybrevifoliol, brevifoliol, 2'-deacetoxydecinnamoyltaxinine J and 2'-deacetoxytaxinine J in yew needles has been developed using a Nova-Pak Phenyl column and a binary gradient profile. The various aspects of analysis such as extraction efficiency, detection limits, reproducibility and peak purity were validated using UV-Vis as well as photodiode array detection.

A 3-Mb high-resolution BAC/PAC contig of 12q22 encompassing the 830-kb consensus minimal deletion in male germ cell tumors

Cytogenetic and molecular genetic analyses have shown that the 12q22 region is recurrently deleted in male germ cell tumors (GCTs), suggesting that this site may harbor a tumor suppressor gene (TSG). Previous loss of heterozygosity (LOH) analyses identified a consensus minimal deleted region between the markers D12S377 and D12S296, and a YAC clone contig covering the region was generated. Here, we describe a high-resolution sequence-ready physical map of this contig covering a 3-Mb region. The map comprised of 52 cosmids, 49 PACs, and 168 BACs that were anchored to the previous YAC contig; 99 polymorphic, nonpolymorphic, EST, and gene-based markers are now placed on this map in a unique order. Of these, 61 markers were isolated in the present study, including one that was polymorphic. In addition, we have narrowed the minimal deletion to approximately 830 kb between D12S1716 (proximal) and P382A8-AG (distal) by LOH analysis of 108 normal-tumor DNAs from GCT patients using 21 polymorphic STSs. These physical and deletion maps should prove useful for identification of the candidate TSG in GCTs, provide framework to generate complete DNA sequence, and ultimately generate a gene map of this segment of the chromosome 12. [The sequence data described in this paper have been submitted to the Genome Survey Sequence under accession nos. AQ254896-AQ254955 and AQ269251-AQ269266. Online supplementary material is available at http://www.genome.org]

A 3-Mb high-resolution BAC/PAC contig of 12q22 encompassing the 830-kb consensus minimal deletion in male germ cell tumors

Cytogenetic and molecular genetic analyses have shown that the 12q22 region is recurrently deleted in male germ cell tumors (GCTs), suggesting that this site may harbor a tumor suppressor gene (TSG). Previous loss of heterozygosity (LOH) analyses identified a consensus minimal deleted region between the markers D12S377 and D12S296, and a YAC clone contig covering the region was generated. Here, we describe a high-resolution sequence-ready physical map of this contig covering a 3-Mb region. The map comprised of 52 cosmids, 49 PACs, and 168 BACs that were anchored to the previous YAC contig; 99 polymorphic, nonpolymorphic, EST, and gene-based markers are now placed on this map in a unique order. Of these, 61 markers were isolated in the present study, including one that was polymorphic. In addition, we have narrowed the minimal deletion to approximately 830 kb between D12S1716 (proximal) and P382A8-AG (distal) by LOH analysis of 108 normal-tumor DNAs from GCT patients using 21 polymorphic STSs. These physical and deletion maps should prove useful for identification of the candidate TSG in GCTs, provide framework to generate complete DNA sequence, and ultimately generate a gene map of this segment of the chromosome 12. [The sequence data described in this paper have been submitted to the Genome Survey Sequence under accession nos. AQ254896-AQ254955 and AQ269251-AQ269266. Online supplementary material is available at http://www.genome.org]

Inhibition of tumor necrosis factor alpha alters resistance to Mycobacterium avium complex infection in mice

Increased production of tumor necrosis factor alpha (TNF-alpha) appears to play an important role in the progression of human immunodeficiency virus disease. One treatment strategy being explored is the use of TNF-alpha inhibitors. TNF-alpha also appears to be important in conferring resistance to infections, and the inhibition of this cytokine may exacerbate the emergence of opportunistic pathogens, such as Mycobacterium avium complex (MAC). The present study examines the possibility that inhibition of TNF-alpha will increase the progression of disease in mice infected with MAC. C57BL/6 beige (bg/bg) mice have been shown to be highly susceptible to infection with MAC and are routinely used for testing of antimycobacterial drugs. However, bg/bg mice are known to exhibit impaired phagocyte and natural killer cell function. Since these cell types are important sources of TNF-alpha, the susceptibility of the bg/bg strain to infection with MAC was compared with those of the heterozygous (bg/+) and wild-type (+/+) strains of C57BL/6 mice. The susceptibilities of the bg/bg and bg/+ strains of mice infected with MAC were found to be comparable. The +/+ strain was the least susceptible. Mycobacterial burden and serum TNF-alpha levels increased over time in all the strains of mice tested. The bg/+ strain of C57BL/6 mice was then chosen to measure the activity of TNF-alpha antagonists. Treatment with dexamethasone decreased serum TNF-alpha levels and increased mycobacterial burden. Treatment with anti-TNF-alpha antibody or pentoxifylline did not significantly alter serum TNF-alpha levels but increased mycobacterial burden. Treatment with thalidomide neither consistently altered mycobacterial burden in the spleens or livers of infected mice nor affected serum TNF-alpha levels.

Childhood hepatocellular adenoma in familial adenomatous polyposis: mutations in adenomatous polyposis coli gene and p53

BACKGROUND & AIMS

Infantile and childhood liver tumors have been found in 0.42% of individuals with a germline mutation in the adenomatous polyposis coli (APC) gene. This study analyzed a hepatocellular adenoma of a 2-year-old child at risk for familial adenomatous polyposis to identify genetic alterations in hepatic tumors initiated by APC germline mutations.

METHODS

Mutation screening was performed for the APC gene (protein truncation test and DNA sequence analysis), p53 gene (complementary DNA cloning and sequencing), and members of the Ras gene family (complementary DNA sequence analysis).

RESULTS

Both the mother and child had a germinal CGA-->TGA transition at codon 1451 leading to an Arg1451Ter stop mutation in the APC gene. Loss of the wild-type APC allele as a second hit revealed hemizygosity of the inherited mutation in the tumor. Furthermore, a CGC-->CAC transition in the p53 gene of the adenoma resulted in an Arg-->His missense mutation in codon 175. No loss of heterozygosity was detected at the p53 locus. Ras gene mutations were not found.

CONCLUSIONS

Biallelic inactivation of APC gene and p53 mutation are early events in hepatocellular tumorigenesis. Additional reports will confirm whether inherited APC gene mutations between codon 1444 and 1578 increase the risk for hepatic tumors.

In the absence of endogenous IFN-gamma, mice develop unimpaired IL-12 responses to Toxoplasma gondii while failing to control acute infection

The relationship between IFN-gamma and IL-12 in generating innate immune responses and resistance to acute Toxoplasma gondii infection was assessed in T. gondii-exposed IFN-gamma knockout (gko) mice. Gko mice, in contrast to wild-type (wt) animals, rapidly succumbed to infection with either the avirulent ME49 strain or, surprisingly, an attenuated temperature-sensitive mutant strain, ts4. Microscopic examination of peritoneal exudates from infected gko mice demonstrated that mortality is associated with unchecked tachyzoite replication. Nevertheless, both wt and gko animals developed a peritoneal inflammatory response that in gko animals was greater due to a 5- to 10-fold increase in the number of granulocytes recruited to the site of infection. In addition, IL-12 production in gko mice was both unimpaired and functional since a significant, albeit lower than wt, IL-12-dependent NK cell response developed in these animals. Regardless, no evidence for an IFN-gamma-independent protective function for IL-12 or NK cells was apparent since in vivo treatment of gko mice with an IL-12-neutralizing mAb ablated the NK cell response, but did not decrease survival. Together, these data identify distinct functions for IL-12 and IFN-gamma in host resistance to T. gondii: IL-12 precedes and initiates synthesis of IFN-gamma, while the latter lymphokine directly controls parasite growth and diminishes the contribution of IL-4- and IL-5-producing T cell subsets.

In the absence of endogenous IFN-gamma, mice develop unimpaired IL-12 responses to Toxoplasma gondii while failing to control acute infection

The relationship between IFN-gamma and IL-12 in generating innate immune responses and resistance to acute Toxoplasma gondii infection was assessed in T. gondii-exposed IFN-gamma knockout (gko) mice. Gko mice, in contrast to wild-type (wt) animals, rapidly succumbed to infection with either the avirulent ME49 strain or, surprisingly, an attenuated temperature-sensitive mutant strain, ts4. Microscopic examination of peritoneal exudates from infected gko mice demonstrated that mortality is associated with unchecked tachyzoite replication. Nevertheless, both wt and gko animals developed a peritoneal inflammatory response that in gko animals was greater due to a 5- to 10-fold increase in the number of granulocytes recruited to the site of infection. In addition, IL-12 production in gko mice was both unimpaired and functional since a significant, albeit lower than wt, IL-12-dependent NK cell response developed in these animals. Regardless, no evidence for an IFN-gamma-independent protective function for IL-12 or NK cells was apparent since in vivo treatment of gko mice with an IL-12-neutralizing mAb ablated the NK cell response, but did not decrease survival. Together, these data identify distinct functions for IL-12 and IFN-gamma in host resistance to T. gondii: IL-12 precedes and initiates synthesis of IFN-gamma, while the latter lymphokine directly controls parasite growth and diminishes the contribution of IL-4- and IL-5-producing T cell subsets.

Genomic distribution of 5' TTCCA 3' repeat motif and its diagnostic potential in human Y-chromosome-related anomalies

We have studied genomic distribution of a simple repeat motif 5' TTCCA 3' derived from the DYZ1 fraction of the human Y chromosome employing restriction fragment length polymorphism and in situ hybridization techniques. This has led us to develop a synthetic DNA based genetic marker specific to human genome. Randomly selected human genomic DNA from both sexes, digested with a total of 16 restriction enzymes, OAT20Y probe comprising four repeat units of 5'TTCCA 3' motif failed to reveal fragment length polymorphisms. In contrast, with most of the enzymes, several multilocus monomorphic bands and with a few enzymes, smeary signals were detected. In situ hybridization of the OAT20Y probe with human chromosomes revealed grains on the long arm of the Y chromosome, whereas the X-chromosome and autosomes showed random distribution of the grains without any preferential labeling in the centromeric or telomeric regions. The OAT20Y probe uncovers a 3.4 kb isomorphic band exclusively in the human male DNA digested with Hae III enzyme. Using the OAT20Y probe, we have detected the presence of Y chromosome in mosaic cell populations of Turner's patients with dysgenetic gonads and high levels of LS/FSH. The presence of Y chromosome in these patients has been associated with an increased risk of gonadoblastoma. The OAT20Y probe offers sensitivity and accuracy for the detection of Y-chromosome-bearing cells in a mosaic cell population and, consequently, help in better management of the patients.

Multiple products in the protein truncation test due to alternative splicing in the adenomatous polyposis coli (APC) gene

Reverse transcription-polymerase chain reaction (RT-PCR)-based analyses of the adenomatous polyposis coli (APC) gene encompassing exons 1-15 revealed a complex pattern of products that were due to alternative splicing of exons 9, 10A and 14. The multiplicity of polypeptide chains obtained from T7-promoter-directed in vitro translation of the RT-PCR product pool was confirmed immunochemically to correspond to the mRNA isoforms, but not to represent products of internal initiation of translation. This observation is of particular relevance for the diagnostic protein truncation test (PTT), since this assay will pick up mRNA variants derived from physiological splice events, e.g., skipping of exons 9, 10A and 14. In vitro-translated proteins of reduced molecular weight were therefore detectable in healthy individuals. We extended this observation to the PTT of cDNA encompassing APC exons 1-14 of familial adenomatous polyposis patients. Knowledge of the normal polypeptide pattern seen in the diagnostic in vitro translation assay allowed us not only to identify translational stop mutations, but even to detect a splice acceptor mutation of exon 14 as a result of quantitative changes of the isoform pattern. Western immuno blot analysis on protein extracts of Epstein-Barr virus-immortalized lymphocytes of the same patients revealed that mutations accessible to the RT-PCR PTT yield intracellularly undetectable APC proteins.

HIV infection suppresses type 1 lymphokine and IL-12 responses to Toxoplasma gondii but fails to inhibit the synthesis of other parasite-induced monokines

Individuals infected with Toxoplasma gondii normally develop resistance to the parasite, resulting in an asymptomatic chronic infection. In AIDS patients, this resistance is lost leading to reactivation of infection and development of encephalitis. To characterize the cytokine response of T. gondii-infected individuals, PBMC were cultured in vitro in the presence or absence of crude tachyzoite Ags (STAg). When stimulated with STAg, PBMC from T. gondii-infected donors, but not controls, produced high levels of Type 1 lymphokines (IL-2 and IFN-gamma) as well as the monokine IL-12, in the absence of detectable Type 2 lymphokines (IL-4 and IL-5). In contrast, cells of individuals from both groups produced high levels of IL-1, IL-6, and TNF-alpha when exposed to the same Ag preparation. By using highly purified elutriated cells, we demonstrated that monocytes are a major source of these monokines. The above findings were further expanded by analyzing the cytokine responses induced by STAg in PBMC from patients co-infected with T. gondii and HIV. Our results demonstrate that parasite-specific IL-2 and IFN-gamma responses are greatly impaired even before AIDS development, as is IL-12 synthesis by PBMC from HIV-infected individuals stimulated with STAg. In contrast, the release of IL-6 and TNF-alpha triggered by STAg is either not affected or augmented during HIV infection.

HIV infection suppresses type 1 lymphokine and IL-12 responses to Toxoplasma gondii but fails to inhibit the synthesis of other parasite-induced monokines

Individuals infected with Toxoplasma gondii normally develop resistance to the parasite, resulting in an asymptomatic chronic infection. In AIDS patients, this resistance is lost leading to reactivation of infection and development of encephalitis. To characterize the cytokine response of T. gondii-infected individuals, PBMC were cultured in vitro in the presence or absence of crude tachyzoite Ags (STAg). When stimulated with STAg, PBMC from T. gondii-infected donors, but not controls, produced high levels of Type 1 lymphokines (IL-2 and IFN-gamma) as well as the monokine IL-12, in the absence of detectable Type 2 lymphokines (IL-4 and IL-5). In contrast, cells of individuals from both groups produced high levels of IL-1, IL-6, and TNF-alpha when exposed to the same Ag preparation. By using highly purified elutriated cells, we demonstrated that monocytes are a major source of these monokines. The above findings were further expanded by analyzing the cytokine responses induced by STAg in PBMC from patients co-infected with T. gondii and HIV. Our results demonstrate that parasite-specific IL-2 and IFN-gamma responses are greatly impaired even before AIDS development, as is IL-12 synthesis by PBMC from HIV-infected individuals stimulated with STAg. In contrast, the release of IL-6 and TNF-alpha triggered by STAg is either not affected or augmented during HIV infection.