Implementation of Genetic Engineering and Novel Omics Approaches to Enhance Bioremediation: A Focused Review

Bioremediation itself is considered to be a cost effective soil clean-up technique and preferred over invasive physical and chemical treatments. Besides increasing efficiency, application of genetic engineering has led to reduction in the time duration required to achieve remediation, overcoming the so called 'Achilles heel' of Bioremediation. Omics technologies, namely genomics, transcriptomics, proteomics, and metabolomics, are being employed extensively to gain insights at genetic level. A wise synchronised application of these approaches can help scrutinize complex metabolic pathways, and molecular changes in response to heavy metal stress, and also its fate i.e., uptake, transport, sequestration and detoxification. In the present review, an account of some latest achievements made in the field is presented.

Functional Outcome of Bilateral Total Knee Replacement in Advanced Osteoarthritis in Simultaneous Versus Staged Procedure

Osteoarthritis (OA) is a chronic, progressive disease involving the degeneration of cartilage and joint tissue, resulting in pain and disability. Bilateral total knee arthroplasty (TKA) is is an effective intervention that improves quality of life, reduces pain and increases functional capability. This study was performed to compare the functional outcomes between staged and simultaneous total knee arthroplasty. This prospective interventional study was carried out in Arthroscopic and Arthroplasty unit of BSMMU, Dhaka from January 2017 to December 2018. A total of 60 OA patients underwent TKA were included in this study. Thirty patients underwent simultaneous TKA procedure and 30 patients underwent staged TKA procedures performed with 1-6 months between stages were included. Pre-operative and post operative data were collected. Data were analyzed using SPSS 12.0. Numerical data were analyzed using unpaired t test and categorical data were analyzed using Chi-Square test. A value of p<0.05 was considered statistically significant. Mean age of the study subjects was 60.47±10.13 years in staged group and 59.30±9.90 years in simultaneous group. Male to female ratio was 1:1.5 in staged group and 1:2 in simultaneous group. Mean BMI of the study subjects was 30.70±4.91kg/m² in staged group and 30.06±4.79kg/m² in simultaneous group (p>0.05). In both groups, maximum study subjects were housewife (33.3% vs. 33.3%). In staged group 13.3% and 16.7% in simultaneous group were heavy worker; 20.0% in staged group and 16.7% in simultaneous group were medium worker (p>0.05). Pain, motion, stability and function were significantly changed after surgery comparing before surgery.Infection was observed in 10.0% cases in both groups. Stiffness was observed in 10.0% cases in staged group but in 6.7% cases in simultaneous group. Even final outcome showed better in simultaneous procedure, there was no significant difference between two procedures. The outcome of both simultaneous andstaged procedure of bilateral total knee replacement in Advanced Osteoarthritis is similar.

Harnessing Pisum sativum-Glomus mosseae symbiosis for phytoremediation of soil contaminated with lead, cadmium, and arsenic

This study investigates the impact of Glomus mosseae on heavy metal(loid) (HM) uptake efficiency of pea (Pisum sativum L.) plants along with physiological and biochemical parameters. Plants were grown in soil spiked with HMs (Pb and As: 50 and 100 mg kg-1; Cd: 25 and 50 mg kg-1) and a multi-metal(loid) (Mm: Pb + Cd + As) combination, inoculated/non-inoculated with G. mosseae. A dose-dependent increase in HM accumulation was observed in plants upon harvest at 60 days. Plant growth, concentration of photosynthetic pigments, total nitrogen, and carbohydrates reduced, whereas enzymatic [catalase (CAT), superoxide dismutase (SOD), and ascorbate peroxidase (APX)] and non-enzymatic (proline and total phenolics) antioxidants increased upon HM stress. Inoculation with G. mosseae led to an increase in plant growth, concentration of photosynthetic pigments, carbohydrate, nitrogen, and defence antioxidants (whereas proline decreased) which was statistically significant (p ≤ 0.05). This symbiosis can be applied for onsite remediation of Pb and Cd contaminated soil by virtue of accumulation efficiency and adaptive response of pea plants inoculated with G. mosseae. Since the amount of HMs in edible parts exceeded the maximum permissible limits recommended by FAO/WHO, pea must not be cultivated in HM-contaminated soil for agricultural purpose due to associated toxicity. Novelty statement   To our knowledge, phytoremediation potential of Pea in synchronization with Glomus mosseae has not been evaluated previously. This study highlights:  • Pea-AMF symbiosis can be applied for Pb and/or Cd phytoremediation.  • Target Hazard Quotient >1 for Pb, Cd and As; caution to food chain exposure required.  • Nonenzymatic (proline, TPC) and enzymatic (CAT, SOD, APX) antioxidants play a key role in ROS detoxification.

Metal(loid) induced toxicity and defense mechanisms in Spinacia oleracea L.: Ecological hazard and Prospects for phytoremediation

A pot study was conducted to assess the phytoremediation potential of Spinach plants along with their physiological and biochemical response when grown in soil contaminated with heavy metal(loid)s (HMs). Plants were grown under different doses of Pb, Cd and As; and their metal(loid) accumulation efficiency was studied upon harvest; expressed in terms of bioabsorption coefficient (BAC), bioconcentration factor (BCF) and translocation factor (TF). Results showed significant (p ≤ 0.05) difference in physiological and biochemical mechanisms of plants as detected through decrease in concentration of cellular constituents (pigments, carbohydrates, total nitrogen content); and increase in antioxidants (both enzymatic and non-enzymatic). Despite of accumulating high amount of HMs in tissues, no visible signs of toxicity were seen; and hence the efficient survival and defense mechanism shown by spinach plants conclude that they are a viable option to be used for phytoremediation of sites contaminated with Cd and Pb. Since the content of Cd and Pb in edible part was higher than safe limits prescribed by USEPA, the present investigation also highlights the ecological hazards that may result upon cultivation of spinach in contaminated soil for agricultural purpose; or its accidental exposure to food chain when grown for phytoremediation.

EDTA-Assisted Metal Uptake in Raphanus sativus L. and Brassica oleracea L.: Assessment of Toxicity and Food Safety

A study was conducted to determine the effect of ethylenediaminetetraacetic acid (EDTA) on phytoextraction potential of radish and cabbage. Plant biomass, photosynthetic pigments, proline and phenolics were significantly affected by the accumulation of heavy metals (HM). The metal uptake potential was increased significantly by the application of EDTA. Target hazard quotient (THQ) associated with exposure of these contaminants to food chain was calculated. Agronomic interventions to increase mineral levels in crops often increases the leaf concentrations only, the mineral concentration in edible portions are not increased at desired level due to low mobility of Zn in phloem. Since the leaves of both these crops are edible and a component of staple vegetarian diet, biofortification through Zn present in soil and its solubilization and mobilization through chelators can be implemented. However in no such instance these crops should be consumed when grown on Pb contaminated soil due to associated hazards.

Effect of Glomus mossae on accumulation efficiency, hazard index and antioxidant defense mechanisms in tomato under metal(loid) Stress

In the present study, the phytoremedation potential along with growth, physiological and biochemical response of tomato (Solanum lycopersicum) was assessed under heavy metal(loid) (HM) and arbuscular mycorrhizal fungus (AMF) amendment. Effect of AMF on uptake and accumulation of metal(loid)s was assessed and accumulation characteristics were expressed in terms of bioabsorption coefficient (BAC), bioconcentration factor (BCF), translocation factor (TLF) and transfer factor (TF). Results showed that AMF-inoculated plants showed not only a better growth, chlorophyll content, strengthened non-enzymatic and enzymatic defense mechanism, but also accumulated higher concentration of metal(loid)s. The correlation between biochemical and physiological parameters was significant at 0.01 level. A significant difference (p ≤ 0.001) in antioxidant enzyme activity was found on increasing metal(loid) dose and application of AMF. The accumulation of Cd and Pb in edible part exceeded the chronic reference dose stated by USEPA. The target hazard quotient (THQ) was >1 for Cd and Pb, whereas <1 for As. The study shows that tomato has good potential as Cd and Pb phytoremediator, hence must not be consumed when grown on Cd or Pb contaminated sites.

Citrus Epicarp-Derived Biochar Reduced Cd Uptake and Ameliorates Oxidative Stress in Young Abelmoschus esculentus (L.) Moench (okra) Under Low Cd Stress

Due to the important role of biochar (BC) in reducing metal-toxicity in plants, this study was aimed at assessing the potential of citrus epicarp-derived BC in ameliorating Cd toxicity in young Abelmoschus esculentus (okra) under low Cd toxicity. Okra was grown in soil amended with BC at four treatment levels for 49 days as follows: control (A), sole 1.4 mg Cd/kg-spiked soil (B), 1.4 mg Cd/kg-spiked soil + 1% BC (C) and 1.4 mg Cd/kg-spiked soil + 3% BC (D). The results showed a dose-dependent reduction in shoot accumulation of Cd due to the BC application. In addition, compared to control and sole Cd-amended soil, BC treatments (both at 1% and 3% w/w) decreased the oxidative stress, and enhanced activities of enzymatic and non-enzymatic antioxidants in the young okra. Generally, the application of BC to the soil was effective in ameliorating the Cd-induced oxidative stress in okra with limited shoot bioaccumulation of Cd.

Metal(loid) accumulation in aquatic plants of a mining area: Potential for water quality biomonitoring and biogeochemical prospecting

Aquatic bryophytes can accumulate extremely high levels of chemical elements because of their unique morphology and physiology which is markedly different from vascular plants. Four aquatic mosses-Fontinalis squamosa, Brachythecium rivulare, Platyhypnidium riparioides, Thamnobryum alopecurum-and a freshwater red alga Lemanea fluviatilis along with water samples from the streams of Góis mine region in Central Portugal were analyzed for 46 elements. Despite being below detection levels in the water samples, the elements Zr, V, Cr, Mo, Ru, Os, Rh, Ir, Pt, Ag, Ge and Bi were obtained in the plant samples. The moss T. alopecurum had the highest mean concentrations of 19 elements followed by B. rivulare (15 elements). Maximum accumulation of Rb, Ta and Au, however, was seen in the alga L. fluviatilis. Bioconcentration factors > 10⁶ were obtained for a few metals. The investigation confirms that aquatic bryophytes can be suitable for water quality biomonitoring and biogeochemical prospecting in fresh water bodies owing to their high accumulative capacity of multi-elements from their aquatic ambient.

Assessment of edibility and effect of arbuscular mycorrhizal fungi on Solanum melongena L. grown under heavy metal(loid) contaminated soil

Arbuscular mycorrhizal fungi (AMF) aids in plant establishment at heavy metal(loid) (HM) contaminated soils, strengthening plant defense system along with promoting growth. A pot experiment was carried out to evaluate the effect of AMF on eggplants grown under HM stress. Further, the potential health risks of HM exposure to the humans via dietary intake of eggplant were also estimated. Results showed that AMF application improved growth, biomass and antioxidative defense response of plants against HM stress. Significant difference (p ≤ 0.001) in parameters under study was found on increasing metal dose and on application of AMF. Among metal(loid)s maximum uptake was recorded for Pb (29.64mgkg^-1 in roots; 23.08mgkg^-1 in shoot) followed by As (3.84mgkg^-1 in roots; 8.20mgkg^-1 in shoot) and, Cd (0.96mgkg^-1 in roots; 2.12mgkg^-1 in shoot). Based on the accumulation of HM in edible part, Hazard Quotient (HQ) was calculated. HQ was found to be > 1 for Pb, which highlights the risks associated with consumption of Eggplants grown on Pb contaminated soil. However this potential, which was further enhanced by application of AMF, can be harnessed for on-site remediation of Pb contaminated soils. The content of Cd and As in the edible part was found to be within safe limits (HQ < 1) when compared to chronic reference dose stated by USEPA.

Comparative Study of Patellar Tendon Graft versus Hamstrings Graft for Anterior Cruciate Ligament Reconstruction

Graft selection for primary anterior cruciate ligament reconstruction is very important part of knee stability. The purpose of this Qasi experimental study was to compare the clinical outcomes after ACL reconstruction using either a BPTB graft or a four-strand hamstrings graft and conducted from January 2012 to December 2013. Patients presented with a symptomatic unilateral ACL rupture who were underwent ACL reconstruction by using either BPTB or Hamstrings graft, IPD of Department of Orthopedics at Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka as well as in a private hospital in Dhaka, Bangladesh were selected as study population. Patients were divided into Group A who were treated with the patellar tendon bone graft and Group B patients who were received hamstrings tendon graft. All surgery was performed by the same surgeon and the both procedures were arthroscopically assisted. Operation was performed at least three (03) weeks after initial trauma. All patients were assessed by independent examiner before surgery, at 6 months, 12 months and then annually by clinically. A total number of 70 patients were recruited for this study. The mean age with SD of Group A and Group B were 27.31±10.91 and 26.97±10.10 years respectively (p=0.892). Tegner scores were measured preoperatively and post-operatively. The score were 2.2±1.1 and 2.1±1.0 in preoperatively (p=0.817). In post-operatively the mean score were 6.0±1.7 and 5.8±1.5 in Group A and Group B respectively (p=0.508). Regarding outcome of the operation excellent was 18(51%) cases in both Group A and Group B, good was 15 (43%) and 16(46%) cases in Group A and Group B respectively (p=0.793). In conclusion there was no significant difference between the two groups of the ACL reconstructions cases.

Accumulation of uranium by aquatic plants in field conditions: prospects for phytoremediation

A study was undertaken to determine Uranium concentrations in water and aquatic plants in the uraniferous region of Beiras, Central Portugal. Samples were collected from running water (n=200) at places where aquatic species were observed. Plant samples were collected from 28 species of submerged, free-floating and rooted emergent plants including 2 bryophytes and 1 pteridophyte. Uranium concentrations in surface waters ranged from 0.23 to 1,217 μg L(-1). The aquatic plant species studied, including several previously untested species, exhibited the ability to accumulate U in concentrations many times that of the ambient water. In general submerged plants exhibited higher U content followed by rooted emergent and free floating species. The highest U concentrations were observed in the bryophyte Fontinalis antipyretica (up to 4,979 mg kg(-1)) followed by Callitriche stagnalis (1963mgkg(-1)), Callitriche hamulata (379 mg kg(-1)), Ranunculus peltatus subsp. saniculifolius (243 mg kg(-1)), Callitriche lusitanica (218 mg kg(-1)), and Ranunculus trichophyllus (65.8 mg kg(-1)). In two out of three rooted emergent species U seemed to be preferentially partitioned in rhizome/roots with highest rhizome U content recorded in Typha latifolia (380 mg kg(-1)). Among the free-floating species, the highest U content (42.5 mg kg(-1)) was seen in Lemna minor. The bryophyte F. antipyretica and Callitrichaceae members seem to be promising candidates for the development of phytofiltration methodologies based on U accumulation, abundance and biomass production.

Phytoremedial assessment of flora tolerant to heavy metals in the contaminated soils of an abandoned Pb mine in Central Portugal

Significant accumulation of heavy metals in soils and flora exists around the abandoned Barbadalhos Pb mine in Central Portugal. Soil and plant samples [49 species] were collected from two line transects, LT 1 and LT 2, in the mineralized and non-mineralized area, respectively to gain a comprehensive picture of heavy metals in soils and flora to assess its potential for phytoremediation. Phytosociological inventories of the vegetation were made using the Braun-Blanquet cover-abundance scale. Metal concentrations in soil ranged from (in mg kg(-1)): 98-9330 [Pb], 110-517 [Zn], 7.1-50 [Co], 69-123 [Cr], 31-193 [Cu], 33400-98500 [Fe], 7.7-51 [Ni], 0.95-13 [Ag], 2.8-208 [As], and 71-2220 [Mn] along LT 1; and 24-93 [Pb], 30-162 [Zn], 3.7-34 [Co], 61-196 [Cr], 21-46 [Cu], 24100-59400 [Fe], 17-87 [Ni], 0.71-1.9 [Ag], 4.3-12 [As], and 44-1800 [Mn] along LT 2. Plant metal content ranged from (in mg kg(-1)): 1.11-548 [Pb], 7.06-1020 [Zn], 0.08-2.09 [Co], 0.09-2.03 [Cr], 2.63-38.5 [Cu], 10.4-4450 [Fe], 0.38-8.9 [Ni], and 0.03-1.9 [Ag] along LT 1; and 0.94-11.58 [Pb], 2.83-96.5 [Zn], 0.12-1.44 [Co], 0.21-1.49 [Cr], 1.61-22.7 [Cu], 4.6-2050 [Fe], 0.51-4.81 [Ni], and 0.02-0.31 [Ag] along LT 2. Plants with highest uptake of metals were: Cistus salvifolius (548 mg Pb kg(-1)), Digitalis purpurea (1017 mg Zn kg(-1) and 4450 mg Fe kg(-1)). Mentha suavolens and Ruscus ulmifolius were seen to hyperaccumulate Ag (1.9 and 1 mg Ag kg(-1), respectively). More metals and higher concentrations were traced in plants from LT 1, especially for Pb and Zn.

Metal contamination of soils and plants associated with the glass industry in North Central India: prospects of phytoremediation

INTRODUCTION

The effect of the glass industry on urban soil metal characterization was assessed in the area of Firozabad, India. A comprehensive profile of metal contamination was obtained in five zones each containing five specific sites.

FINDINGS

Zn, Cd, and As showed a greater accumulation, whereas accumulation of Ni and Cu was high in limited samples. Positive correlation was found for the metal pairs Cu-Zn, Cu-Co, and Cu-Cr at P < 0.01. Moderate positive correlation was also observed between Zn-Co, Mn-Cd, Mn-As, Pb-As, and Ni-Cu at P < 0.05. Integrated contamination indices indicate that 60% of the sites were heavily contaminated while 28% were moderately contaminated. Phytoremedial potential of native flora (twenty herbs, three shrubs, and two grasses) was also assessed by analyzing their metal uptake. Individual elements displayed remarkably different patterns of accumulation in soils as well as in plants. Mn, Zn, Cu, and As were predominantly partitioned in shoots, Co and Cd in roots while Pb, Cr, and Ni almost equally between shoots and roots. Most plants exhibited capabilities in mobilizing Co, Pb, Cr, and Ni in the root zone.

CONCLUSION

Potential phytoextractors include Datura stramonium and Chenopodium murale while phytostabilizers include Calotropis procera and Gnaphalium luteo-album. Poa annua showed potential in both categories. None of the species showed phytoremedial potential for Co and Ni.

Bioassay as monitoring system for lead phytoremediation through Crinum asiaticum L

Toxicity of lead in soil is well documented and established. Phytoremediation has gained attention as a cheap, easily applicable, and eco-friendly clean-up technology. Chemical methods are used to assess exact levels and type of pollutants but heavy metal content in soil can also be evaluated indirectly by estimation of phytotoxicity levels using bioassays. Plant bioassays through fast germinating cereals can indicate not only the level of pollution and its effects on growth and survival but also the progress of phytoremediation process. The performance of barley Hordeum vulgare L. seedlings as bioassay for assessment of changes in the levels of lead (Pb) at three concentrations, i.e., 300 (T(1)), 600 (T(2)), and 1,200 ppm (T(3)) in the soil was evaluated while testing the efficiency of Crinum asiaticum L. as a phytoremedial tool. At the first assessment, i.e., 30 DAT (days after treatment) shoot and root lengths of seedlings decreased with increasing concentrations of Pb. As the study progressed, a decrease in levels of Pb was accompanied by better germinability and growth of barley. At 120 DAT seedling growth in all the treatments were comparable to control. In T(1), T(2), and T(3) soils, 74.5%, 83.7%, and 91.2% reduction in lead content was observed at 120 DAT. Highly significant correlations between decreasing pollutant (Pb) content in the soil, seed germination, and seedling growth of barley H. vulgare were found. The differences in root and shoot length as well as overall growth pattern are indicative of the suitability of barley as a bio-monitoring tool.

Phytoextraction potential of Prosopis juliflora (Sw.) DC. with specific reference to lead and cadmium

Root and shoot samples of Prosopis juliflora were assessed for their heavy metal content to evaluate the species as a green solution to decontaminate soils contaminated with lead and cadmium. The highest uptake of both the metals was observed in plants from industrial sites. Sites with more anthropogenic disturbance exhibited reduced chlorophyll levels, stunted growth, delayed and shortened reproductive phase. The ratios of lead and cadmium in leaves to lead and cadmium in soil were in the range of 0.62-1.46 and 0.55-1.71, respectively. Strong correlation between the degree of contamination and concentrations of lead and cadmium in plant samples identifies P. juliflora as an effective heavy metal remediator coupled with environmental stress.

Identification of Calotropis procera L. as a potential phytoaccumulator of heavy metals from contaminated soils in Urban North Central India

Lead and cadmium levels were monitored in soil at fifteen urban (riverbank, roadside, industrial and residential) sites in the north central part of India. Calotropis procera, a hardy xerophytic plant was identified and selected for remedial potential as it was seen growing well at all sites. Root and leaf samples were collected simultaneously with soil samples to assess the characteristics of accumulation and tolerance of Pb and Cd in C. procera. Chlorophyll and phenological studies were undertaken to investigate the health of plants. The overall trend of Pb and Cd content in soil and plant samples was in the order Industrial>Roadside>Riverbank>Residential. The highest uptake of both the metals was observed in plants from industrial sites. Sites with more anthropogenic disturbance like vehicular and machinery exhausts exhibited reduced chlorophyll levels, stunted growth as well as a delayed, shortened reproductive phase. The ratios of Pb in leaves to Pb in soil were in the range of 0.60-1.37; while similar ratios of Cd were in the range of 1.25-1.83. Highly significant correlation coefficients were determined between concentrations of Pb and Cd in the samples with R(2) values 0.839 for soil, 0.802 for leaf and 0.819 for root samples. The strong correlation between the degree of contamination and concentrations of Pb and Cd in plant samples identifies C. procera as an effective heavy metal remediator of contaminated lands coupled with environmental stress.

The sequential effects of estrogen administration and hypertension on cardiac function in ewes

OBJECTIVE

Our objective was to study the effect of estrogen administration and moderate hypertension on left ventricular size, pump function, and contractility in chronically instrumented ewes.

STUDY DESIGN

Ewes were either given 0.06 mg/kg 17beta-estradiol intramuscularly (n = 8) or were made hypertensive (n = 6) by inflation of an occluder around the aorta and were studied weekly. After 3 weeks each ewe received the opposite treatment.

RESULTS

Estrogen administration caused an increase in left ventricular chamber size at a given pressure, fractional shortening (21.9% +/- 2.9% to 28.5% +/- 3.7%), and stroke volume (1.4 +/- 0.3 mL/kg to 1.6 +/- 0.3 mL/kg). Subsequent hypertension further increased left ventricular size at a given pressure but decreased fractional shortening (20.0% +/- 4.4%) and stroke volume (1.3 +/- 0.3 mL/kg). With hypertension first, there was no left ventricular enlargement, even with subsequent estrogen administration, and there were no changes in left ventricular pump function. End-systolic pressure and stress-dimension relationships did not change with either treatment. The end-systolic wall stress-fractional shortening relationship was likewise unchanged, suggesting that neither treatment changed contractility.

CONCLUSIONS

The left ventricle previously exposed to hypertension does not remodel when exposed to estrogen, and cardiac pump function decreases when the estrogen enlarged heart is faced with moderate, subacute hypertension.

Inosine exists in mRNA at tissue-specific levels and is most abundant in brain mRNA

The general view that mRNA does not contain inosine has been challenged by the discovery of adenosine deaminases that act on RNA (ADARs). Although inosine monophosphate (IMP) cannot be detected in crude preparations of nucleotides derived from poly(A)+ RNA, here we show it is readily detectable and quantifiable once it is purified away from the Watson-Crick nucleotides. We report that IMP is present in mRNA at tissue-specific levels that correlate with the levels of ADAR mRNA expression. The amount of IMP present in poly(A)+ RNA isolated from various mammalian tissues suggests adenosine deamination may play an important role in regulating gene expression, particularly in brain, where we estimate one IMP is present for every 17 000 ribonucleotides.

Estrogen-induced left ventricular chamber enlargement in ewes

We studied the chronic effect of administration of a single large intramuscular dose of 17 beta-estradiol on left ventricular chamber size and output in the ewe. Fourteen oophorectomized ewes were successfully instrumented and studied, with measurements made of left ventricular, aortic, right and left atrial pressures, left ventricular stroke volume, and left ventricular minor axis dimension. Unanesthetized ewes were studied before and 1, 2, and 3 wk after intramuscular administration of 0.6 mg/kg 17 beta-estradiol (7 ewes) or 1.5 ml sesame oil placebo (7 ewes). Left ventricular end-diastolic pressure-end-diastolic dimension (LVEDP-EDD) and left ventricular end-diastolic pressure-stroke volume (LVEDP-SV) relationships were quantified during graded inferior vena caval occlusion and volume infusion. Left ventricular end-diastolic diameter was larger after estrogen but not after placebo administration. The LVEDP-EDD relationship shifted progressively rightward, indicating left ventricular chamber enlargement in the estrogen group but was unchanged in the placebo group. The plateau limb of the LVEDP-SV relationship in the estrogen group shifted up from a mean stroke volume of 77.1-89.5 ml/beat and did not change in the placebo group. We conclude that administration of a single large intramuscular dose of 17 beta-estradiol resulted in left ventricular chamber enlargement and increased stroke volume in the ewe.

Maternal left ventricular dimension in pregnancies complicated by fetal growth retardation

Previous studies using two-dimensional chest radiographs have found a significant correlation between prematurity, fetal growth retardation, and the size of the maternal heart. Accordingly, we evaluated maternal left ventricular size and function by M-mode echocardiography near the end of gestation in 42 women with suspected fetal growth retardation and in 79 women whose pregnancies were normal. No significant differences were found between the two groups, implying that maternal left ventricular size and function is adequate in pregnancies complicated by "idiopathic" fetal growth retardation.

The murine complement receptor gene family. III. The genomic and transcriptional complexity of the Crry and Crry-ps genes

The murine CR genes Crry (previously termed mCRY) and Crry-ps (previously termed mCRX) are two distinct, but related, sequences which are the evolutionary homologs to sequences contained within the human CR1 gene. Screening a BALB/c genomic DNA library with the Crry/Crry-ps specific cDNA resulted in the isolation of two clusters of genomic sequences: those specific for Crry and those specific for Crry-ps. The coding sequences of the Crry gene encompass over 25 kb of DNA, whereas the Crry-ps sequences are included within a single 5.6-kb Eco-R1 fragment. The Crry gene consists of 10 separate exons. The first of these contains both the signal sequence and an alternatively spliced 129 bp present in approximately 10% of the Crry transcripts. Of the remaining exons, two encode a single sixty amino acid repeat domain each (A and E), two encode a split sixty amino acid repeat (B), and another encodes two 60 amino acid domains (C and D) fused as one exon. The transmembrane and cytoplasmic regions are both split into two exons each. RNA protection analysis indicates that although there is alternative splicing in the 5' region of the gene, the 3' exons encoding the terminal 60 amino acid repeat, the transmembrane region and cytoplasmic exons are used in the same order in all Crry transcripts. This suggests that the Crry gene product is not found as a secreted protein, but only as a cell surface bound protein. DNA sequence analysis of the Crry-ps gene indicates that this sequence most likely represents a pseudogene resulting from a processed mRNA transcript from the Crry gene. This conclusion is based on the lack of intervening sequences in the Crry-ps gene and the observation that the Crry-ps gene sequence contains both an 11-bp deletion within the "coding" region and a degenerate poly A tail at the 3' end of the homologous sequence. Additionally, RNA protection analysis indicates that mRNA cannot be detected which matches the Crry-ps sequence.

The murine complement receptor gene family. III. The genomic and transcriptional complexity of the Crry and Crry-ps genes

The murine CR genes Crry (previously termed mCRY) and Crry-ps (previously termed mCRX) are two distinct, but related, sequences which are the evolutionary homologs to sequences contained within the human CR1 gene. Screening a BALB/c genomic DNA library with the Crry/Crry-ps specific cDNA resulted in the isolation of two clusters of genomic sequences: those specific for Crry and those specific for Crry-ps. The coding sequences of the Crry gene encompass over 25 kb of DNA, whereas the Crry-ps sequences are included within a single 5.6-kb Eco-R1 fragment. The Crry gene consists of 10 separate exons. The first of these contains both the signal sequence and an alternatively spliced 129 bp present in approximately 10% of the Crry transcripts. Of the remaining exons, two encode a single sixty amino acid repeat domain each (A and E), two encode a split sixty amino acid repeat (B), and another encodes two 60 amino acid domains (C and D) fused as one exon. The transmembrane and cytoplasmic regions are both split into two exons each. RNA protection analysis indicates that although there is alternative splicing in the 5' region of the gene, the 3' exons encoding the terminal 60 amino acid repeat, the transmembrane region and cytoplasmic exons are used in the same order in all Crry transcripts. This suggests that the Crry gene product is not found as a secreted protein, but only as a cell surface bound protein. DNA sequence analysis of the Crry-ps gene indicates that this sequence most likely represents a pseudogene resulting from a processed mRNA transcript from the Crry gene. This conclusion is based on the lack of intervening sequences in the Crry-ps gene and the observation that the Crry-ps gene sequence contains both an 11-bp deletion within the "coding" region and a degenerate poly A tail at the 3' end of the homologous sequence. Additionally, RNA protection analysis indicates that mRNA cannot be detected which matches the Crry-ps sequence.

Vascular pressure-volume relationships in pregnant and estrogen-treated guinea pigs

We investigated the relationship between mean circulatory filling pressure (MCFP) and blood volume in nonpregnant (NP), estrogen-treated (E), and pregnant (P) guinea pigs. Reversible circulatory arrest was produced by rapid ventricular pacing or acetylcholine in unanesthetized animals remote from surgery. MCFP (mmHg) was higher for E (7.1 +/- 0.3) than for NP (5.8 +/- 0.5) or P (5.3 +/- 0.4). The gradient for venous return, the difference between MCFP and right atrial pressure (mmHg), did not differ in NP- (6.0 +/- 0.5), P- (5.8 +/- 0.5), or E- (5.8 +/- 0.4) treated animals. Capacitance, the blood volume (ml/kg) at an MCFP of 6 mmHg, was increased in P (84 +/- 6) and E (89 +/- 7), compared with NP (64 +/- 5) animals. Compliance, the ratio of the change in volume to change in pressure in the range of 6-12 mmHg (ml.kg-1.mmHg-1), was greater in P (4.4 +/- 0.3) than NP (3.5 +/- 0.3) animals. Hexamethonium blockade did not affect MCFP, capacitance, or compliance. We conclude that the effect of blood volume expansion on the circulation in pregnancy cannot be predicted from knowledge of MCFP-blood volume relationships in the nonpregnant animal, because capacitance and compliance are altered. Estrogen administration to nonpregnant animals reproduces some of these effects.

Murine complement receptor gene family. II. Identification and characterization of the murine homolog (Cr2) to human CR2 and its molecular linkage to Crry

CR2, a 145,000 to 150,000 Mr protein which binds specific breakdown products of C3, has been identified on the surface of both human and murine B cells. In order to understand the evolutionary relatedness of the human and murine proteins, we have used the coding sequences from the human CR2 gene to investigate those homologous sequences of murine Cr2. Human CR2 cDNA sequences were used as probes on a cDNA library derived from BALB/c spleen mRNA to identify cross-reacting cDNA sequences. A number of putative cDNA clones encoding murine Cr2 have been isolated and examined. DNA sequence analysis of these Cr2 cDNA clones indicates that they represent the murine homolog to human CR2. mRNA analysis with these Cr2 cDNA clones has revealed a transcription pattern similar to, but distinct from that seen for CR2. Whereas human CR2 coding sequences identify a single mRNA species of approximately 5 kb from human tonsillar mRNA, the murine counterpart identifies four transcripts from murine spleen of approximately 3, 5, 9 and 11 kb in size. The Cr2 cDNA clones which detect the four forms of spleen mRNA overlap in coding sequences and contain exons mapping to three colinear fragments as defined by EcoRI digestion. This suggests that the 3- 5-, 9-, and 11-kb mRNA forms arise by alternative splicing from a single gene. Use of these murine Cr2-specific cDNA clones to isolate their respective genomic sequences has allowed for the linkage of the 3' end of the Cr2 gene to the 5' end of the Crry gene, the evolutionary homolog to human CR1.

Murine complement receptor gene family. II. Identification and characterization of the murine homolog (Cr2) to human CR2 and its molecular linkage to Crry

CR2, a 145,000 to 150,000 Mr protein which binds specific breakdown products of C3, has been identified on the surface of both human and murine B cells. In order to understand the evolutionary relatedness of the human and murine proteins, we have used the coding sequences from the human CR2 gene to investigate those homologous sequences of murine Cr2. Human CR2 cDNA sequences were used as probes on a cDNA library derived from BALB/c spleen mRNA to identify cross-reacting cDNA sequences. A number of putative cDNA clones encoding murine Cr2 have been isolated and examined. DNA sequence analysis of these Cr2 cDNA clones indicates that they represent the murine homolog to human CR2. mRNA analysis with these Cr2 cDNA clones has revealed a transcription pattern similar to, but distinct from that seen for CR2. Whereas human CR2 coding sequences identify a single mRNA species of approximately 5 kb from human tonsillar mRNA, the murine counterpart identifies four transcripts from murine spleen of approximately 3, 5, 9 and 11 kb in size. The Cr2 cDNA clones which detect the four forms of spleen mRNA overlap in coding sequences and contain exons mapping to three colinear fragments as defined by EcoRI digestion. This suggests that the 3- 5-, 9-, and 11-kb mRNA forms arise by alternative splicing from a single gene. Use of these murine Cr2-specific cDNA clones to isolate their respective genomic sequences has allowed for the linkage of the 3' end of the Cr2 gene to the 5' end of the Crry gene, the evolutionary homolog to human CR1.

The murine complement receptor gene family. Analysis of mCRY gene products and their homology to human CR1

The mouse genome contains two sets of gene sequences which are highly homologous to the gene encoding the human C3b/C4b receptor (CR1). These genes, termed murine CRY (mCRY) and murine CRX (mCRX) reside on murine chromosomes 1 and 8, respectively. Analysis of cDNA isolated by using these sequences as probes indicates that there are two related but distinct mRNA which are expressed in a wide variety of murine tissues including spleen, liver, lung, and brain. Both of these transcripts encode proteins which should contain a signal sequence for membrane insertion, a transmembrane/cytoplasmic tail region for membrane anchoring, and five extracellular domains made up of 60 amino acid consensus repeat sequences. The difference between the two is the presence of an additional exon of 129 bp immediately 3' of the signal sequence. This additional exon does not encode a 60 amino acid repeat. The sizes of the mature proteins predicted from the cDNA sequences are 43,998 Mr and 48,680 Mr; however, antisera raised against carboxy-terminal sequences detects a 70,000 Mr protein from murine fibroblasts suggesting a high degree of post-translational modification of the mature protein. A comparison of these murine gene sequences with a partial human CR1 sequence suggests that the human CR1 gene evolved by direct duplication of the ancestral coding sequences contained within these murine genes including those sequences important for membrane anchoring and cytoplasmic protein attachment.

The murine complement receptor gene family. Analysis of mCRY gene products and their homology to human CR1

The mouse genome contains two sets of gene sequences which are highly homologous to the gene encoding the human C3b/C4b receptor (CR1). These genes, termed murine CRY (mCRY) and murine CRX (mCRX) reside on murine chromosomes 1 and 8, respectively. Analysis of cDNA isolated by using these sequences as probes indicates that there are two related but distinct mRNA which are expressed in a wide variety of murine tissues including spleen, liver, lung, and brain. Both of these transcripts encode proteins which should contain a signal sequence for membrane insertion, a transmembrane/cytoplasmic tail region for membrane anchoring, and five extracellular domains made up of 60 amino acid consensus repeat sequences. The difference between the two is the presence of an additional exon of 129 bp immediately 3' of the signal sequence. This additional exon does not encode a 60 amino acid repeat. The sizes of the mature proteins predicted from the cDNA sequences are 43,998 Mr and 48,680 Mr; however, antisera raised against carboxy-terminal sequences detects a 70,000 Mr protein from murine fibroblasts suggesting a high degree of post-translational modification of the mature protein. A comparison of these murine gene sequences with a partial human CR1 sequence suggests that the human CR1 gene evolved by direct duplication of the ancestral coding sequences contained within these murine genes including those sequences important for membrane anchoring and cytoplasmic protein attachment.

Experimental autoimmune myocarditis in the guinea pig

Male and female guinea pigs underwent immunisation with heterologous heart protein (rat heart), complete Freund's adjuvant and pertussis vaccine (immunised) or normal saline (control) at weekly intervals for 6 weeks, and were subsequently studied. In vivo intracardiac pressures, cardiac outputs, blood volumes, in vitro pressure-volume relations, left ventricular collagen contents, light microscopy, direct immunofluorescence, lymphocyte stimulation studies, and serology for circulating anti heart antibody (haemagglutination and radioimmunoassay) were performed. Immunised guinea pigs studied between 5 and 8 weeks following the immunisation protocol demonstrated a 44% increase in LVEDP (p less than 0.005), an increase in right atrial pressure (p less than 0.001), although no change in aortic pressure or cardiac output when compared with controls. Left ventricular weight was increased 20% (p less than 0.001), and in vitro left ventricular volume by 34% (at 8 mmHg distending pressure, p less than 0.001). Lung wet weight was increased 44% (p less than 0.005), and left ventricular collagen content increased 60% (p less than 0.001). Cultured lymphocytes from treated guinea pigs demonstrated a 1.5- to 4.5-fold (dependent upon proximity to last immunisation) increase in radiolabelled thymidine uptake when incubated with guinea pig heart protein compared to controls (p less than 0.001), and circulating anti guinea pig heart antibodies were detected by haemagglutination and radioimmunoassay. Histological examination of the left ventricles revealed inflammatory cell infiltration and myocyte increase to varying degrees in 15 of the 18 treated animals. We conclude that inflammatory, probably immune-mediated, chronic myocarditis can be produced in the guinea pig.

Exercise dynamics in late gestation: effects of physical training

Heart rate and stroke volume were measured serially in subjects at rest in the sitting position and at the onset and end of a 6-minute period of upright bicycle exercise. Twenty-three subjects with normal pregnancy were studied in late gestation and again post partum. Rest and exercise cardiac outputs in late gestation were not different from those in the postpartum period. Heart rate was higher at rest and stroke volume lower during exercise in late gestation than post partum. At the end of exercise, stroke volume fell dramatically in late gestation but not post partum. Ten women prospectively identified as physically fit had responses that were not different from those of the nonfit cohort in late gestation. Post partum, the physically fit women had exercise responses typical of trained persons and different from those of the nonfit cohort. In late gestation, rest and exercise hemodynamics in subjects in the sitting position appeared to be dominated by factors influencing venous return, independent of physical fitness.

Exercise during pregnancy

Theoretical arguments suggest that cardiovascular fitness would be desirable during pregnancy but that high-intensity exercise should be avoided; both notions require rigorous testing. Moderate exercise, by normal women with uncomplicated pregnancy, does not appear to affect fetal health. Coexisting maternal medical or obstetrical complications may contraindicate exercise.

Accelerated respiratory response to moderate exercise in late pregnancy

We studied the rates of change of expired ventilation (VE, BTPS), O2 consumption (VO2, STPD) and CO2 production (VCO2, STPD) at the start and stop of 6 min of 50-W bicycle exercise, comparing 20 healthy young women at 38 weeks of pregnancy (G) and 3 months postpartum (NG). VO2, VCO2 and VE were significantly greater at rest for G than for NG. The absolute increases of VO2 and VCO2 from steady-state rest (SSR) to steady-state exercise (SSE) were the same for G and NG. The absolute increase of VE from SSR to SSE was significantly greater for G than NG. VCO2 and VE increased more rapidly in G than NG, but only during the first 90 sec of exercise. Recovery rates after exercise were equal for G and NG. We believe that lower extremity muscles of G contract on more distended veins at the onset of exercise, forcing increased volumes of venous blood through the lungs, increasing VO2 and VCO2. VE follows VCO2 closely.

Effect of oxygen and of carbon dioxide tension on the incidence of apnea in fetal lambs

Fetal breathing movements (FBM) in unanesthetized lambs in utero were correlated with measurements of arterial blood gases. One hundred and eighty-seven observations, consisting of the incidence of FBM during the hour preceding and the hour after the blood gas determinations, were made on 125 separate days in 30 fetuses of 117 to 146 days' gestational age. Fifty-eight percent of the observations with fetal apnea (FBM 0 to 9% in 2 hours) showed hypoxia (PaO2 less than or equal to 16 torr), whereas only 4% of the observations with FBM greater than 10% were associated with hypoxia. Sevety-eight percent of the hypoxic and normocarbic (PaCO2 42 to 53 torr) observations demonstrated apnea. However, only 44% of hypoxic plus hypercarbic (PaCO2 57 to 63 torr) fetuses were apneic, and with an elevated PaCO2, apnea tended to develop at a lower level of PaO2. We conclude that FBM may persist in the presence of hypercarbia with hypoxia.

Effect of beta-adrenergic suppression by propranolol on coronary collateral development in response to chronic coronary ischemia in dogs

Acute left circumflex coronary artery (LC) occlusion in conscious dogs caused marked ischemia in the myocardium supplied by the occluded artery, as judged by the radioactive microsphere technique for determining blood flow distribution. With the chest open, LC pressure distal to the occlusion fell to 21 +/- 1.9% of aortic pressure. By 8 weeks after gradual LC occlusion with an ameroid constrictor, collateral development had restored coronary blood flow distribution to near-normal under basal conditions and during pacing, at a heart rate of 200 beats/min. The only evidence for ischemia was in the subepicardium within the distribution of the unoccluded left anterior descending artery, which provided the extra collateral blood flow. Distal LC pressure was 70 +/- 1.7% of aortic pressure. Propranolol 160 mg orally every 6 hours for 8 weeks had no detectable effect on coronary collateral development, as judged by blood flow distribution or distal LC pressure. The only significant difference for the propranolol dogs was a slight transmural shift away from the subendocardium in the left anterior descending region.