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1.
Ir Med J ; 112(1): 857, 2019 01 15.
Article in English | MEDLINE | ID: mdl-30719898

ABSTRACT

Aims We report, with review of the literature, the case of a patient who developed a subcutaneous abscess after intravenously injecting his own semen in an attempt to treat longstanding back pain. He had devised this "cure" independent of medical advice. Methods A review of EMBASE, PubMed, google scholar and the wider internet was conducted with an emphasis on parenteral semen for the treatment of back pain and for other medical and non-medical uses. Results There were no other reported cases of intravenous semen injection found across the medical literature. A broader search of internet sites and forums found no documentation of semen injection for back pain treatment or otherwise. Conclusion While suicide attempt by intravenous injection of harmful substances is well described, this unique case demonstrates risks involved with innovative treatments prior to clinical research in the form of phased trials inclusive of safety and efficacy assessments.


Subject(s)
Abscess/etiology , Back Pain/therapy , Chronic Pain/therapy , Complementary Therapies/adverse effects , Connective Tissue Diseases/etiology , Self Medication/adverse effects , Semen , Subcutaneous Tissue , Adult , Humans , Infusions, Intravenous/adverse effects , Injections, Intramuscular/adverse effects , Male , Severity of Illness Index
2.
PLoS One ; 12(10): e0185015, 2017.
Article in English | MEDLINE | ID: mdl-28968421

ABSTRACT

Within a plantation of clonal somatic embryo-derived white spruce trees that belonged to four genotypes, one genotype (G6) has consistently responded for the last 16 years, to the induction of somatic embryogenesis within primordial shoot explants. Analysis of fourteen individuals within this genotype subsequently revealed a group of clonal trees that were nonresponsive. This in turn provided a unique opportunity to conduct differential gene expression analysis in the absence of genotype-specific factors. Absolute qPCR was first used to expand the analysis of several genes previously identified via microarray analysis to be differentially expressed during SE induction, along with the inclusion of two nonresponsive genotypes. While this demonstrated a high level of repeatability within, and between, responsive and nonresponsive genotypes, it did not support our previous contention that an adaptive stress response plays a role in SE induction responsiveness, at least with respect to the candidate genes we analyzed. RNAseq analysis was then used to compare responsive and nonresponsive G6 primordial shoots during the somatic embryogenesis induction treatment. Although not analyzed in this study, this included samples of callus and embryonal masses previously generated from G6 explants. In addition to revealing a large number of differentially expressed genes, de novo assembly of unmapped reads was used to generate over 25,000 contigs that potentially represent previously unidentified transcripts. This included a MADS-domain gene that was found to be the most highly differentially expressed gene within responsive shoot explants during the first seven days of the induction treatment.


Subject(s)
Gene Expression Regulation, Plant , Picea/genetics , Seeds/metabolism , Adaptation, Physiological , Genes, Plant , Picea/embryology , Picea/physiology , Plant Shoots/metabolism , Sequence Analysis, RNA , Stress, Physiological
3.
PLoS One ; 10(6): e0128679, 2015.
Article in English | MEDLINE | ID: mdl-26039876

ABSTRACT

BACKGROUND: Although somatic embryogenesis has an unprecedented potential for large-scale clonal propagation of conifers, the ability to efficiently induce the embryonal cultures required for somatic embryo production has long been a challenge. Furthermore, because early stage zygotic embryos remain the only responsive explants for pines, it is not possible to clone individual trees from vegetative explants at a commercial scale. This is of particular interest for adult trees because many elite characteristics only become apparent following sexual maturation. FINDINGS: Shoot explants collected from adult radiata pine trees were cultured on four induction media differing in plant growth regulator composition, either directly after collection or from in vitro-generated axillary shoots. Six callus lines were selected for microscopic examination, which failed to reveal any embryonal masses (EM). qPCR expression profiling of five of these lines indicated that explant type influenced the absolute level of gene expression, but not the type of genes that were expressed. The analysis, which also included three EM lines induced from immature zygotic embryos, encompassed five categories of genes reflective of metabolic, mitotic and meristematic activity, along with putative markers of embryogenicity. Culture medium was found to have no significant impact on gene expression, although differences specific to the explant's origin were apparent. Expression of transcriptional factors associated with vegetative meristems further suggested that all of the callus lines possessed a substantive vegetative character. Most notable, however, was that they all also expressed a putative embryogenic marker (LEC1). CONCLUSIONS: While limited in scope, these results illustrate the utility of expression profiling for characterizing tissues in culture. For example, although the biological significance of LEC1 expression is unclear, it does present the possibility that these callus lines possess some level of embryogenic character. Additionally, expression of vegetative meristem markers is consistent with their vegetative origin, as are differences in expression patterns as compared with EM.


Subject(s)
Gene Expression Regulation, Plant , Pinus/genetics , Plant Proteins/genetics , Seeds/genetics , Transcription Factors/genetics , Culture Media/chemistry , Culture Media/pharmacology , Gene Expression Profiling , Gene Expression Regulation, Developmental , Genetic Markers , Hydroponics , Microarray Analysis , Pinus/growth & development , Pinus/metabolism , Plant Growth Regulators/pharmacology , Plant Proteins/metabolism , Plant Shoots/genetics , Plant Shoots/growth & development , Plant Shoots/metabolism , Plant Somatic Embryogenesis Techniques , Plant Stems/genetics , Plant Stems/growth & development , Plant Stems/metabolism , Seeds/drug effects , Seeds/growth & development , Seeds/metabolism , Transcription Factors/metabolism , Zygote/growth & development , Zygote/metabolism
4.
Obes Surg ; 24(10): 1724-8, 2014 Oct.
Article in English | MEDLINE | ID: mdl-24805912

ABSTRACT

BACKGROUND: Few reports have compared laparoscopic sleeve gastrectomy (LSG) to laparoscopic Roux-en-Y procedure (LRNY). This study aims at comparing the 5-year follow-up results of mini gastric bypass (MGB or omega gastric bypass (OGB)) and LSG in terms of weight loss, weight regain, complications, and resolution of co-morbidities. METHODS: A retrospective analysis of the prospectively collected database was done from the start of our bariatric practice from February 2007 to August 2008 (minimum 5-year follow-up). During this period, 118 patients underwent LSG. These patients were matched in age, gender, preoperative weight, and BMI to 104 patients who underwent MGB in the same time period. The results were compared. RESULTS: Follow-up was achieved in 72 MGB vs 76 LSG patients up to 5 years. The mean BMI for the MGB and LSG group was 44 ± 3.1 and 42 ± 5.2 kg/m(2), respectively (P < 0.001). The average percentage of excess weight loss (%EWL) for MGB vs LSG was 63 vs 69 % at 1 year and 68 vs 51.2 % at 5 years (P = 0.166), respectively. Post-op gastro-esophageal reflux disease (GERD) was seen in 2.8 % MGB patients and marginal ulcer was diagnosed in 1 MGB patient (1.4 %). GERD was seen in 21 % post-LSG patients. CONCLUSIONS: Both MGB and LSG are safe, short, and simple operations. Weight loss is similar in MGB and LSG in the first years, but lesser %EWL with LSG at 5 years (68 % in MGB vs 51 % in LSG). Post-op GERD is more common after LSG.


Subject(s)
Gastrectomy , Gastric Bypass , Laparoscopy , Obesity, Morbid/surgery , Adult , Aged , Body Mass Index , Female , Follow-Up Studies , Humans , India , Male , Middle Aged , Retrospective Studies , Time Factors , Treatment Outcome , Weight Loss , Young Adult
5.
Obes Surg ; 24(9): 1430-5, 2014 Sep.
Article in English | MEDLINE | ID: mdl-24682767

ABSTRACT

BACKGROUND: We started laparoscopic mini-gastric bypass (MGB) for the first time in India in February 2007 for its reported safety, efficacy, and easy reversibility. METHODS: A retrospective review of prospectively maintained data of all 1,054 consecutive patients (342 men and 712 women) who underwent MGB at our institute from February 2007 to January 2013 was done. RESULTS: Mean age was 38.4 years, preoperative mean weight was 128.5 kg, mean BMI was 43.2 kg/m(2), mean operating time was 52 ± 18.5 min, and mean hospital stay was 2.5 ± 1.3 days. There were 49 (4.6%) early minor complications, 14 (1.3%) major complications, and 2 leaks (0.2%). In late complications, one patient had low albumin and one had excess weight loss; MGB was easily reversed in both (0.2%). Marginal ulcers were noted in five patients (0.6%) during follow-up for symptomatic dyspepsia, and anemia was the most frequent late complication occurring in 68 patients (7.6%). Patient satisfaction was high, and mean excess weight loss was 84, 91, 88, 86, 87, and 85% at years 1 to 6, respectively. CONCLUSION: This study confirms previous publications showing that MGB is quite safe, with a short hospital stay and low risk of complications. It results in effective and sustained weight loss with high resolution of comorbidities and complications that are easily managed.


Subject(s)
Gastric Bypass/statistics & numerical data , Laparoscopy/statistics & numerical data , Obesity, Morbid/surgery , Adolescent , Adult , Aged , Body Mass Index , Female , Gastric Bypass/adverse effects , Gastric Bypass/methods , Humans , India , Laparoscopy/adverse effects , Laparoscopy/methods , Length of Stay , Male , Middle Aged , Operative Time , Patient Satisfaction , Retrospective Studies , Treatment Outcome , Weight Loss , Young Adult
6.
Leukemia ; 28(7): 1467-71, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24441288

ABSTRACT

We previously reported preliminary findings that post induction imatinib mesylate (340 mg/m(2)/day), in combination with intensive chemotherapy, resulted in outcomes similar to blood and marrow transplant (BMT) for pediatric patients with Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL). We now report 5-year outcomes of imatinib plus intensive chemotherapy in 91 children (1-21 years) with and without allogeneic BMT (N=91). We explore the impacts of additional chromosomal abnormalities and minimal residual disease (MRD) by flow cytometry on outcomes. The 5-year disease-free survival was similar for Cohort 5 patients, treated with chemotherapy plus imatinib (70%±12%, n=28), sibling donor BMT patients (65%±11%, n=21) and unrelated donor BMT patients (59±15%; P=0.60, n=13). Patients with additional cytogenetic abnormalities had worse outcomes (P=0.05). End induction (pre-imatinib) MRD was not prognostic for Cohort 5 or allogeneic BMT patients, although limited by small numbers. The re-induction rate following relapse was similar to other higher-risk ALL groups. Longer-term follow-up confirms our initial observation of substantially good outcomes for children and adolescents with Ph+ ALL treated with imatinib plus intensive chemotherapy with no advantage for allogeneic BMT.


Subject(s)
Antineoplastic Agents/therapeutic use , Benzamides/therapeutic use , Piperazines/therapeutic use , Precursor Cell Lymphoblastic Leukemia-Lymphoma/drug therapy , Protein Kinase Inhibitors/therapeutic use , Pyrimidines/therapeutic use , Adolescent , Antineoplastic Agents/administration & dosage , Benzamides/administration & dosage , Child , Child, Preschool , Chromosome Aberrations , Follow-Up Studies , Humans , Imatinib Mesylate , Infant , Piperazines/administration & dosage , Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics , Precursor Cell Lymphoblastic Leukemia-Lymphoma/mortality , Prognosis , Protein Kinase Inhibitors/administration & dosage , Pyrimidines/administration & dosage , Recurrence , Remission Induction , Treatment Outcome , Young Adult
8.
Curr Oncol ; 16(2): 29-33, 2009 Mar.
Article in English | MEDLINE | ID: mdl-19370176

ABSTRACT

In Canada people affected by cancer access psychosocial care and support from two systems. In the conventional medical system, psychosocial professionals focus mainly on screening for and treating those most distressed by their diagnosis. Many patients and family members go beyond this step to find information and support provided by community-based organizations (CBOS). This article outlines the components of complete cancer care effectively provided by CBOS and why the integration of the two systems of care is critical in delivering seamless high-quality psychosocial care for all.

9.
Nucleic Acids Res ; 32(22): e178, 2004 Dec 15.
Article in English | MEDLINE | ID: mdl-15601990

ABSTRACT

Quantitative real-time PCR has revolutionized many aspects of genetic research, biomedical diagnostics and pathogen detection. Nevertheless, the full potential of this technology has yet to be realized, primarily due to the limitations of the threshold-based methodologies that are currently used for quantitative analysis. Prone to errors caused by variations in reaction preparation and amplification conditions, these approaches necessitate construction of standard curves for each target sequence, significantly limiting the development of high-throughput applications that demand substantive levels of reliability and automation. In this study, an alternative approach based upon fitting of fluorescence data to a four-parametric sigmoid function is shown to dramatically increase both the utility and reliability of quantitative real-time PCR. By mathematically modeling individual amplification reactions, quantification can be achieved without the use of standard curves and without prior knowledge of amplification efficiency. Combined with provision of quantitative scale via optical calibration, sigmoidal curve-fitting could confer the capability for fully automated quantification of nucleic acids with unparalleled accuracy and reliability.


Subject(s)
Polymerase Chain Reaction/methods , Calibration , Kinetics , Models, Theoretical , Polymerase Chain Reaction/standards , Regression Analysis
10.
Mol Genet Genomics ; 270(1): 78-86, 2003 Oct.
Article in English | MEDLINE | ID: mdl-12920576

ABSTRACT

PCR amplification with degenerate primers targeted to highly conserved amino acid motifs within the MYB domain was used to demonstrate that black spruce (Picea mariana) possesses a diverse MYB gene family. Amino acid sequence comparisons revealed three broad MYB subfamilies, one of which shares extensive similarity with maize C1, a central regulator of anthocyanin biosynthesis. A cDNA clone encoding a MYBR2R3 protein from P. mariana with high levels of sequence homology to maize C1 was shown to transactivate the Bz2 promoter in combination with maize R in embryonal tissues of both black spruce and larch. Functional dependence on the maize R protein, and the presence of a conserved C-terminal GIDPxTH motif, support the conservation of MYBR2R3 function in conifers, and demonstrate that the basic components of MYBR2R3-dependent transcriptional regulation have been conserved between angiosperms and gymnosperms.


Subject(s)
DNA-Binding Proteins/genetics , Picea/genetics , Plant Proteins/genetics , Zea mays/genetics , Amino Acid Sequence , Base Sequence , Conserved Sequence , DNA Primers , DNA-Binding Proteins/chemistry , Gene Expression Regulation , Molecular Sequence Data , Multigene Family , Phylogeny , Picea/classification , Plant Proteins/chemistry , Polymerase Chain Reaction , Seeds , Sequence Homology, Amino Acid , Trees/genetics , Zea mays/classification
11.
Nucleic Acids Res ; 31(16): e93, 2003 Aug 15.
Article in English | MEDLINE | ID: mdl-12907745

ABSTRACT

Fluorescent monitoring of DNA amplification is the basis of real-time PCR, from which target DNA concentration can be determined from the fractional cycle at which a threshold amount of amplicon DNA is produced. Absolute quantification can be achieved using a standard curve constructed by amplifying known amounts of target DNA. In this study, the mathematics of quantitative PCR are examined in detail, from which several fundamental aspects of the threshold method and the application of standard curves are illustrated. The construction of five replicate standard curves for two pairs of nested primers was used to examine the reproducibility and degree of quantitative variation using SYBER Green I fluorescence. Based upon this analysis the application of a single, well- constructed standard curve could provide an estimated precision of +/-6-21%, depending on the number of cycles required to reach threshold. A simplified method for absolute quantification is also proposed, in which quantitative scale is determined by DNA mass at threshold.


Subject(s)
Polymerase Chain Reaction/methods , Polymerase Chain Reaction/standards , DNA/genetics , DNA/metabolism , Kinetics , Linear Models , Mathematics , Reference Standards , Reproducibility of Results
12.
Plant Cell Rep ; 21(11): 1080-7, 2003 Jul.
Article in English | MEDLINE | ID: mdl-12836002

ABSTRACT

Seventy transgenic tissue lines (translines) of three spruce species ( Picea mariana, P. glauca and P. abies) were characterized with respect to the integration pattern of the gus (beta-glucuronidase) gene, and the level of GUS activity was determined in 81 lines. The majority of the P. mariana translines (18 lines of 22) integrated multicopies of the transgene, whereas mostly single integrations were detected in the other two species. The activity levels of GUS varied widely among the individual translines of P. mariana, and there was a strong indication that the logarithm of GUS activity increased with the number of gus copies ( P=0.0003) in lines with one to five known insertions (uncensored). The average level of GUS activity, in lines that integrated one gene copy, was the highest in white spruce followed by black spruce and Norway spruce (22.7, 16.5 and 6.3 nmol 4-methylumbelliferone min(-1 )mg(-1 )protein, respectively).


Subject(s)
Gene Expression Regulation, Plant , Picea/genetics , Transgenes/genetics , Culture Techniques , Gene Dosage , Glucuronidase/genetics , Glucuronidase/metabolism , Picea/classification , Plants, Genetically Modified , Species Specificity
13.
Plant Cell Rep ; 21(6): 619-24, 2003 Feb.
Article in English | MEDLINE | ID: mdl-12789439

ABSTRACT

Despite the success of the MUG fluorometric assay for quantitative analysis of beta-glucuronidase (GUS) activity within a vast array of transgenic plant species and tissues, attempts to apply this protocol for analysis of woody plants has been found to be problematic, primarily due to the interfering effects of phenolics and other secondary metabolites. Our analysis of transgenic spruce needles and poplar leaves illustrates that low tissue mass to extract volume, along with the inclusion of polyvinylpolypyrolidone and either beta-mercaptoethanol or metabisulphite, are essential for producing reliable results. The primary action of these additives was found to involve increased GUS extractability and the preservation of GUS activity during extract manipulation, but they were not completely effective in eliminating GUS enzymatic inhibitors. Normalization of GUS activity upon DNA concentration was also found to be an effective alternative to protein concentration, providing the ability to make cross-species and inter-tissue comparisons of gusA transgene activity.


Subject(s)
Glucuronidase/metabolism , Picea/genetics , Plants, Genetically Modified/genetics , Populus/genetics , Fluorescence , Fluorometry/methods , Glucuronidase/genetics , Picea/metabolism , Plant Extracts/genetics , Plant Extracts/metabolism , Plant Leaves/genetics , Plant Leaves/metabolism , Plants, Genetically Modified/metabolism , Populus/metabolism , Reproducibility of Results
14.
Obes Surg ; 11(3): 276-80, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11433900

ABSTRACT

BACKGROUND: Results of the laparoscopic Mini-Gastric Bypass (MGB) are reported. METHODS: 1,274 MGB patients are continuously monitored as part of an online computer tracking data-base system. RESULTS: Mean preoperative weight (+/- Standard Deviation) was 132 +/- 21 kg, BMI 47 +/- 7. Mean excess weight loss was 51% at 6 months, 68% at 12 months and 77% at 2 years. The mean operating-time was 36.9 +/- 33.5 minutes. The shortest time was 19 minutes. Hospital stay was 1.5 +/- 1.6 days. The overall complication rate has been 5.2%. The overall rate of deep vein thrombosis and pulmonary embolism was 0.08% and 0.16% respectively. The leak rate was 1.6%. There was one hospital death, 0.08%. Associated medical illnesses were either completely reversed or markedly improved. CONCLUSIONS: The MGB is safe, results in major weight loss, has a short operating-time, and has a short hospital stay. The MGB appears to meet many of the criteria of an "ideal" weight loss operation.


Subject(s)
Gastric Bypass/methods , Laparoscopy , Adult , Aged , Female , Gastric Bypass/adverse effects , Humans , Male , Middle Aged , Obesity, Morbid/surgery
15.
Eur J Pharmacol ; 415(1): 39-44, 2001 Mar 09.
Article in English | MEDLINE | ID: mdl-11245850

ABSTRACT

The cerebral circulation is innervated by calcitonin gene-related peptide (CGRP) containing fibers originating in the trigeminal ganglion. During a migraine attack, there is a release of CGRP in conjunction with the head pain, and triptan administration abolishes both the CGRP release and the pain at the same time. In the search for a novel treatment of migraine, a non-peptide CGRP antagonist has long been sought. Here, we present data on a human cell line and human and guinea-pig isolated cranial arteries for such an antagonist, Compound 1 (4-(2-Oxo-2,3-dihydro-benzoimidazol-1-yl)-piperidine-1-carboxylic acid [1-(3,5-dibromo-4-hydroxy-benzyl)-2-oxo-2-(4-phenyl-piperazin-1-yl)-ethyl]-amide). On SK-N-MC cell membranes, radiolabelled CGRP binding was displaced by both CGRP-(8-37) and Compound 1, yielding pK(i) values of 8.9 and 7.8, respectively. Functional studies with SK-N-MC cells showed that CGRP-induced cAMP production was antagonised by both CGRP-(8-37) and Compound 1 with pA(2) values of 7.8 and 7.7, respectively. Isolated human and guinea pig cerebral arteries were studied with a sensitive myograph technique. CGRP induced a concentration-dependent relaxation in human cerebral arteries which was antagonized by both CGRP-(8-37) and Compound 1 in a competitive manner. In guinea pig basilar arteries, CGRP-(8-37) antagonised the CGRP-induced relaxation while Compound 1 had a weak blocking effect. The clinical studies of non-peptide CGRP antagonists are awaited with great interest.


Subject(s)
Calcitonin Gene-Related Peptide Receptor Antagonists , Cerebral Arteries/drug effects , Piperazines/pharmacology , Piperidines/pharmacology , Animals , Binding, Competitive , Calcitonin Gene-Related Peptide/pharmacology , Cell Membrane/metabolism , Cerebral Arteries/metabolism , Cerebral Arteries/physiology , Cyclic AMP/metabolism , Dose-Response Relationship, Drug , Guinea Pigs , Humans , In Vitro Techniques , Peptide Fragments/pharmacology , Tumor Cells, Cultured , Vasodilation/drug effects
17.
Plant Cell Physiol ; 41(8): 982-7, 2000 Aug.
Article in English | MEDLINE | ID: mdl-11038059

ABSTRACT

The phenylpropanoid pathway has important functions in angiospermous plants following exposure to environmental stresses, such as wounding and pathogen attack, that lead to production of compounds including lignin, flavonoids and phytoalexins. Chalcone synthase (CHS) is a key enzyme in this pathway, catalyzing the first step in flavonoid biosynthesis, whose expression can be induced in response to environmental stress. To explore the response of conifers to environmental stress, expression of spruce CHS and its inducibility were investigated. A partial spruce CHS cDNA clone was isolated using PCR. Examination of the expression patterns of the CHS gene family in white spruce revealed accumulation of CHS mRNA in needle tissue following mechanical wounding, or application of signal molecules like jasmonic acid or methyl jasmonate. Repeated mechanical wounding or jasmonate applications had an enhancing effect on transcript accumulation in needles. A systemic accumulation of CHS mRNAs following wounding was also observed. Conifers thus appear to possess a general wound response similar to that found for angiosperms, which includes CHS induction as well as its inducibility by jasmonic acid and airborne methyl jasmonate.


Subject(s)
Acyltransferases/biosynthesis , Cycadopsida/enzymology , Cyclopentanes/pharmacology , Plant Growth Regulators/pharmacology , Acyltransferases/genetics , Cloning, Molecular , Enzyme Induction , Molecular Sequence Data , Oxylipins , Physical Stimulation , RNA, Messenger/analysis , RNA, Plant/analysis , Sequence Analysis, DNA
18.
Arch Surg ; 135(9): 1116-8, 2000 Sep.
Article in English | MEDLINE | ID: mdl-10982524
19.
Plant Cell Rep ; 19(4): 358-362, 2000 Mar.
Article in English | MEDLINE | ID: mdl-30754787

ABSTRACT

Using particle bombardment of mature somatic embryos followed by the induction of secondary embryogenesis in the presence of hygromycin, we produced over 90 lines of transgenic embryonal masses expressing ß-glucuronidase from two genotypes of black spruce. Transformation efficiencies of up to 7% (1 transgenic line per 14 embryos bombarded) were achieved by extending the period of selection from 8 to 12 weeks. Proliferation of transformed embryonal masses in the presence of hygromycin had no effect on either embryogenicity or embryo maturation. Southern blot hybridization and PCR amplification confirmed the presence of the hygromycin phosphotransferase gene in genomic DNA. The expression of the ß-glucuronidase gene in the needles of regenerated seedlings support the potential for long-term transgene expression in spruce.

20.
Tree Physiol ; 20(10): 701-707, 2000 May.
Article in English | MEDLINE | ID: mdl-12651520

ABSTRACT

Significant reductions in needle water content were observed in white spruce (Picea glauca (Moench) Voss), black spruce (Picea mariana (Mill) B.S.P.), and jack pine (Pinus banksiana Lamb.) seedlings in response to a 10-day drought, although turgor was apparently maintained. When the seedlings were re-watered after the drought, jack pine needles regained their original saturated volume, whereas white spruce and black spruce needles did not. Significant drought-induced reductions in turgor-loss volume (i.e., tissue volume at the point of turgor loss) were observed in shoots of all three species, especially jack pine. Repeated exposure to 7 days of drought or treatment with the cytochrome P(450) inhibitor, paclobutrazol ((2RS,3RS)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-pentan-3-ol), reduced seedling height relative to that of untreated controls in all three species. The reductions in saturated and turgor-loss needle volumes in the paclobutrazol-treated seedlings were comparable with those of seedlings subjected to a 10-day drought. The treatment-induced reductions in shoot and needle water contents enabled seedlings to maintain turgor with tissue volumes close to, or below, the turgor-loss volume of untreated seedlings. Paclobutrazol-treated seedlings subsequently survived drought treatments that were lethal to untreated seedlings.

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