Dietary hempseed reduces platelet aggregation.
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Animals↗
Biomedical subjects
R Ganguly
Publications and source records attributed to R Ganguly.
Effect of dietary hempseed intake on cardiac ischemia-reperfusion injury.
Polyunsaturated fatty acids (PUFAs) have significant, cardioprotective effects against ischemia. Hempseed contains a high proportion of the PUFAs linoleic acid (LA) and alpha-linolenic acid (ALA), which may have opposing effects on postischemic heart performance. There are no reported data concerning the cardiovascular effects of dietary hempseed intake. A group of 40 male Sprague-Dawley rats were distributed evenly into four groups that were fed for 12 wk a normal rat chow supplemented with hempseed (5% and 10%), palm oil (1%), or a 10% partially delipidated hempseed that served as a control. Plasma ALA and gamma-linolenic acid levels were significantly elevated in the rats that were fed a 5% or 10% hempseed-supplemented diet, but in heart tissue only ALA levels were significantly elevated in the rats fed these diets compared with control. After the dietary interventions were completed, postischemic heart performance was evaluated by measuring developed tension, resting tension, the rates of tension development and relaxation, and the number of extrasystoles. Hearts from rats fed a hempseed-supplemented diet exhibited significantly better postischemic recovery of maximal contractile function and enhanced rates of tension development and relaxation during reperfusion than hearts from the other groups. These hearts, however, were not protected from the occurrence of extrasystoles, nor were the increases in resting tension altered during ischemia or reperfusion as a function of any dietary intervention. Our data demonstrate that dietary hempseed can provide significant cardioprotective effects during postischemic reperfusion. This appears to be due to its highly enriched PUFA content.
Animals↗
Effect of SDS on the self-assembly behavior of the PEO-PPO-PEO triblock copolymer (EO)20(PO)70(EO)20.
The mixed micellar system comprising the poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide)-based triblock copolymer (EO)(20)(PO)(70)(EO)(20) (P123) and the anionic surfactant sodium dodecyl sulfate (SDS) has been investigated in aqueous media by small-angle neutron scattering (SANS) and viscosity measurements. The aggregation number of the copolymer in the micelles decreases upon addition of SDS, but a simultaneous enhancement in the degree of micellar hydration leads to a significant increase in the micellar volume fraction at a fixed copolymer concentration. This enhancement in the micellar hydration leads to a marked increase in the stability of the micellar gel phase until it is destroyed at very high SDS concentration. Mixed micellar systems with low and intermediate SDS concentrations form the micellar gel phase in much wider temperature and copolymer concentration ranges than the pure copolymer micellar solution. A comparison of the observed results with those for the copolymers (EO)(26)(PO)(40)(EO)(26) (P85) and (EO)(99)(PO)(70)(EO)(99) (F127) suggests that the composition of the copolymers plays a significant role in determining the influence of SDS on the gelation characteristics of the aqueous copolymer solutions. Copolymers with high PO/EO ratios show an enhancement in the stability of the gel phase, whereas copolymers with low PO/EO ratios show a deterioration of the same in the presence of SDS.
Journal Article↗
Mathematical model for the cancer stem cell hypothesis.
Recent research on the origin of brain cancer has implicated a subpopulation of self-renewing brain cancer stem cells for malignant tumour growth. Various genes that regulate self-renewal in normal stem cells are also found in cancer stem cells. This implies that cancers can occur because of mutations in normal stem cells and early progenitor cells. A predictive mathematical model based on the cell compartment method is presented here to pose and validate non-intuitive scenarios proposed through the neural cancer stem cell hypothesis. The growths of abnormal (stem and early progenitor) cells from their normal counterparts are ascribed with separate mutation probabilities. Stem cell mutations are found to be more significant for the development of cancer than a similar mutation in the early progenitor cells. The model also predicts that, as previously hypothesized, repeated insult to mature cells increases the formation of abnormal progeny, and hence the risk of cancer.
Animals↗
Effect of "inverse melting transition" of aqueous triblock copolymer solutions on solute rotational dynamics.
Rotational dynamics of two structurally similar hydrophobic solutes, 2,5-dimethyl-1,4-dioxo-3,6-diphenylpyrrolo[3,4-c]pyrrole (DMDPP) and 1,4-dioxo-3,6-diphenylpyrrolo[3,4-c]pyrrole (DPP), has been investigated in 30% wv aqueous solution of triblock copolymer, poly(ethylene oxide)(20)-poly(propylene oxide)(70)-poly(ethylene oxide)(20) as a function of temperature. This study has been undertaken in an attempt to explore how the dynamics of a solute molecule solubilized in a copolymer solution is influenced when it undergoes sol-to-gel transition. It has been observed that the anisotropy decays of both DMDPP and DPP can be described by biexponential functions in the sol as well as in the gel phase. This observation has been rationalized on the basis of the probe molecule undergoing two different kinds of motion rather than being located in two different regions of the micelle. Even in the gel phase, which results as a consequence of micelle-micelle entanglement due to an increase in their volume fraction, the rotational relaxation of the solutes is similar to that observed in the micellar solution. The outcome of this work indicates that even though these gels have very high macroscopic viscosities and hence do not flow, the microenvironments experienced by the solutes are akin to that of a micellar solution.
Journal Article↗
Sodium chloride and ethanol induced sphere to rod transition of triblock copolymer micelles.
Dynamic light scattering (DLS), small-angle neutron scattering (SANS), and viscosity studies have been carried out to examine the influence of NaCl and ethanol on the structure of triblock copolymer [(EO)20(PO)70(EO)20] (EO = ethylene oxide; PO = propylene oxide) micelles in aqueous medium. The studies show that while the pure triblock copolymer solutions do not show any significant growth of the micelles on approaching the cloud point, the presence of a small amount of ethanol (5-10%) induces a sphere to rod shape transition of micelles at high temperatures. Interestingly, this ethanol induced sphere to rod transition of micelles can be brought down to room temperature (25 degrees C) with the addition of NaCl. It is also found that NaCl alone cannot induce such sphere to rod transitions and excess ethanol suppresses them by increasing their transition temperature.
Journal Article↗
Simulating thermal power plant processes on a message passing environment.
Simulators play a very important role in the operation of thermal power plants and also in the design of control systems for these plants. To cater to this requirement elaborate methodologies have been developed to simulate thermal power plant processes in an interactive way. Due to the intensive computations involved, such simulators use one or more high through-put computers known as the simulation computers. This paper puts forward a method where parallel processing on a low latency message passing environment has been used to simulate thermal power plant processes following a modular approach. This eliminates the need of an expensive high through-put simulation computer, thus cutting down the hardware cost associated with a simulator and increasing the system reliability manifold.
Journal Article↗
Forty years of solitude: life-history divergence and behavioural isolation between laboratory lines of Drosophila melanogaster.
The study of the early stages of speciation can benefit from examination of differences between populations of known history that have been separated for a short time, such as a few thousands of generations. We asked whether two lines of Drosophila melanogaster that were isolated more than 40 years ago have evolved differences in life-history characters, or have begun to evolve behavioural or postzygotic isolation. One line, which is resistant to DDT, showed lower egg production and a shorter lifespan than a susceptible line. These differences are not a pleiotropic effect of resistance because they are not attributable to the chromosome that contains the resistance factors. The two lines have begun to become behaviourally isolated. Again, the isolation is not attributable to genes on the chromosome that contains resistance factors. The lines show only prezygotic isolation; there is no evidence of reduced fitness of F1 or F2 hybrids. These lines and others like them, should be excellent subjects for analyses of genetic changes that could lead to speciation.
Age Factors↗
Is squatting a triggering factor for stroke in Indians?
BACKGROUND: Undocumented observations of ours suggested increased occurrence of strokes in the early hours of the morning and in the toilets where most Indians still squat. The present study has been designed to assess the validity of this observation and to identify the likely triggering factor in stroke onset in such situations. MATERIAL AND METHODS: Part A of the study looked into stroke onset data of 100 consecutive CT-confirmed stroke patients specially in relation to time of day, place, posture and activity of the individual. Part B of the study included 67 healthy volunteers (age 24-49 years) whose supine and squatting blood pressure (BP) were measured and the differences noted. Part C of the study consisted of repeating the same procedure in 104 known hypertensives on treatment (age 28-60 years). RESULTS: Part A of the study revealed that most strokes (52%) occurred in the morning and at home (86%) and over a third (36%) while in toilets. Thirty-six per cent of the strokes occurred while the subjects squatted, mostly during the act of defecation. More than half of the haemorrhagic strokes occurred while the subjects were in squatting position. In normal healthy volunteers squatting produced a small (8.09 +/- 7.04 mmHg) but significant rise in systolic blood pressure (SBP) but not in diastolic blood pressure (DBP) (0.9 +/- 7.38 mmHg). In contrast, in treated hypertensives squatting produced a significantly higher rise in both SBP (14.49 +/- 11.63 mmHg) and DBP(9.10 +/- 9.19 mmHg). CONCLUSION: The relationship of the clinical observations regarding stroke onset with the BP changes noted on squatting in healthy as well as hypertensive subjects appears to be more than fortuitous. Squatting induced rise in BP appears to be an important triggering factor for stroke onset in subjects at risk in India.
Adult↗
Squatting, blood pressure and stroke.
Most Indians still adopt squatting posture in toilets. In a group of 67 healthy volunteers, squatting produced a small (8.09 +/- 7.04 mm Hg) but significant rise in systolic blood pressure (SBP) but not in diastolic (DBP). However, in a group of randomly selected treated hypertensives (N=104) squatting produced a much greater and significant rise in both SBP (14.46 +/- 11.63 mm Hg) and DBP (9.10 +/- 9.19 mm Hg). The possible clinical significance of this rise of BP in squatting has been evaluated in 100 consecutive CT proved patients with stroke by analysing their stroke onset data in relation to time, place, posture and activity. Most strokes (52%) occurred in the morning hours (5 am-9 am) and at home (86%) and over a third (36%) while in toilets. Thirty six percent of strokes occurred when the subjects squatted, mostly during defecation. More than half of hemorrhagic strokes occurred in the squatting position. The relationship of these clinical observations with the BP changes noted above on squatting appears to be more than fortuitous. We would suggest that hypertensive subjects and those at risk of stroke should avoid squatting and urge physicians to check squatting BP while monitoring anti-hypertensive therapy.
Adult↗
Factors on the third chromosome affect the level of cyp6a2 and cyp6a8 expression in Drosophila melanogaster.
The expression of two second chromosome-linked cytochrome P450 genes, Cyp6a2 and Cyp6a8, of Drosophila melanogaster was measured in various strains. Six different strains, including ry(506) and 91-C, showed low or undetectable levels of CYP6A2 and CYP6A8 mRNAs, suggesting that low expression is the wild-type phenotype of Cyp6a2 and Cyp6a8 genes. In the 91-R and MHIII-D23 strains, however, both these genes are overexpressed. In order to examine the genetic basis of Cyp6a2 and Cyp6a8 expression, CYP6A2 and CYP6A8 RNA levels were measured in the F1 hybrids of overproducer (91-R and MHIII-D23) and underproducer (ry(506) and 91-C) strains. Results showed that the total amounts of CYP6A2 and CYP6A8 mRNAs in the F1 hybrids were lower than half the amounts of these RNAs found in the overproducer parental strains. This suggested that the underproducer strains carry loci which downregulate Cyp6a2 and Cyp6a8 gene expression. To determine the chromosome linkage of these loci, several stocks homozygous for the second chromosome of overproducer 91-R strain and, therefore, homozygous for the Cyp6a2-91R and Cyp6a8-91R alleles were synthesized. The third chromosomes in all these stocks were from the underproducer ry(506) strain. The levels of expression of both Cyp6a2-91R and Cyp6a8-91R genes in these three stocks were significantly lower than that observed in the 91-R strain. One of these stocks, named iso-2, showing reduced expression, was used to synthesize two new isogenic stocks by resubstituting the third chromosome of ry(506) origin with third chromosomes of the 91-R strain. Expression of both Cyp6a2-91R and Cyp6a8-91R alleles was found to be much higher in these two resubstituted isogenic stocks than in the progenitor iso-2 stock. Taken together, these results suggest that the second chromosome-linked Cyp6a2 and Cypa8 genes are regulated by loci present on the third chromosome, and the wild-type function of these loci is to repress these two Cyp genes. The data also suggest that Cyp6a2 and Cyp6a8 overexpression in the 91-R and MHIII-D23 strains is more likely due to mutation in the repressor locus (or loci) rather than in the cis-regulatory sequences of the Cyp6a2 and Cyp6a8 genes.
Alleles↗
Exposure of medical students to body fluids.
Three hundred forty-two students at 3 Florida medical schools were surveyed concerning occupational exposures to blood and body fluids during their 3rd-year clerkship. The 16-item questionnaire was anonymously returned by 150 students, and differences among groups were assessed at p < .05. Most of the students complied with universal precautions guidelines (UVPG); 62 reported 101 exposures, including 9 with HIV-positive blood and body fluids. Most of the exposed students knew about the guidelines but regarded the incidents as irrelevant to their safety or supervision training. Noncompliant students reported significantly more exposures than compliant students. Time constraints, inconvenience of using gloves during procedures, and belief that patients were at low HIV risk discouraged adherence to the guidelines. Common practices following exposure were "no action" or "washed area only" without medical follow-up. Medical students' UVPG adherence should be increased by workload modification, user-friendly safety products, and supervised practice training in clinical exposure settings.
Adult↗
Constitutive and barbital-induced expression of the Cyp6a2 allele of a high producer strain of CYP6A2 in the genetic background of a low producer strain.
The levels of one or more cytochrome P450 (CYP) enzymes and the respective mRNAs are found to be higher in insecticide-resistant insects than in susceptible insects. To understand better how insects regulate the levels of CYPs, we examined the expression of the Cyp6a2 gene in various strains of Drosophila melanogaster. We also took a transgenic approach to understand the molecular mechanisms that are involved in strain variation of Cyp6a2 expression. RNA blot analysis showed that the constitutive expression of Cyp6a2 varies from strain to strain; the level of CYP6A2 mRNA is barely detectable in the underproducer ry506 strain, whereas it is very high in the overproducer 91-R and MHIII-D23 strains. The long terminal repeat (LTR) of mobile element 17.6 that is found in the 3' untranslated region (UTR) of the Cyp6a2 gene of some strains does not appear to have any role on the steady-state CYP6A2 mRNA level. We also found that the Cyp6a2 gene is inducible by barbital in 91-R, ry506 as well as 91-C, which carries an LTR insertion. To examine the genetic background of the underproducer ry506 strain with respect to Cyp6a2 expression, we transformed the ry506 strain with the Cyp6a2 allele of the overproducer 91-R strain (Cyp6a2-91 R) and measured the constitutive and barbital-induced expression of the Cyp6a2-91 R transgene in the transformed flies. The Cyp6a2-91 R transgene carrying 129 bp of DNA upstream of the ATG codon did not show any constitutive or barbital-induced expression in the ry506 host genome. However, transgenes with 1331 and 985 bp upstream DNA showed similar levels of constitutive expression that were higher than that of the endogenous Cyp6a2 gene of the ry506 host strain, but lower than the expression of the same gene in the 91-R strain. Both these transgenes, with 1331 and 985 bp upstream DNA, also showed induction with 0.1 M barbital. DNA sequence analysis revealed that in both 91-R and ry506, the upstream DNA between +1 and -985 bp contains a distal and a proximal group of three potential barbie boxes, i.e. cis-elements that are thought to be involved in barbiturate-mediated induction of CYP genes. Except for four bases located near the distal cluster of barbie boxes and two other bases, the base sequence of the upstream DNA is identical in ry506 and 91-R strains. These results suggest that the underproducer ry506 strain has the trans-regulatory factors to support constitutive and induced expression of the Cyp6a2-91 R allele carrying DNA between -129 and -1331 bp regions. Possible reasons for low constitutive expression of the endogenous Cyp6a2 gene and moderate level of expression of the Cyp6a2-91 R allele in the ry506 genetic background are discussed.
Alleles↗
Hepatitis B immunization in a university student population.
In the United States, hepatitis B virus infection occurs predominantly among adolescents and young adults, despite the availability of an effective vaccine. Immunization status and hepatitis B virus (HBV) vaccine acceptance among 505 students visiting the student health services of a large southern university were investigated. Only 58 students had received HBV vaccine. The cost of the vaccine was paid by the students personally (35.5%) or by their parents (34.5%) or employers (31.0%). Nearly half of the students (45.7%) did not know their vaccination status. Lower immunization percentages were found among Hispanics, men, persons of lower education levels, and students aged 25 years and under. Being immunized was related to the perception that the vaccine was affordable, although most students (95.7%) said that the cost of HBV vaccine was excessive. Health professionals' emphasis on the need for HBV vaccination and a reduction in the price of the vaccine could improve HBV immunization rates among university students.
Adult↗
Three second chromosome-linked clustered Cyp6 genes show differential constitutive and barbital-induced expression in DDT-resistant and susceptible strains of Drosophila melanogaster.
The level of expression of the Cyp6a2 gene is much higher in the DDT-resistant 91-R strain than in the susceptible 91-C strain of Drosophila melanogaster (Waters et al. (1992b) Proc. Natl. Acad. Sci. USA, 89, 4855-4859). To understand the role of Cyp6a2 and related genes in insecticide resistance, we have isolated and characterized two new Cyp6 genes from the 91-R strain. The polypeptides encoded by these two genes, Cyp6a8 and Cyp6a9, show 77 and 75% amino acid sequence similarity, and 60 and 55% identity with Cyp6a2 of D. melanogaster, respectively. In the genome, Cyp6a8 and Cyp6a9 genes are closely clustered within 4 kb and map at region 51C of the second chromosome. In between them another Cyp gene is present which is more related to Cyp6a9 than to Cyp6a8. The Cyp6a8 gene which is transcriptionally highly active in 91-R, moderately active in ry506 and silent in the 91-C strain hybridizes with 2.0- and 1.8-kb RNAs. Two different-sized RNAs, 2.1 and 1.8 kb, also hybridize with the Cyp6a9 and/or Cyp6a9-related genes. While the level of 2.1-kb RNA is similar in all three strains, the level of 1.8-kb RNA is highest in the 91-R strain and barely detectable in 91-C strain. Transgenic experiments showed that a 8.3-kb BamHI fragment contains the cis-regulatory elements for the expression of both Cyp6a8 and Cyp6a9-related genes. Barbital induces all these genes in all three strains and increases the levels of the two Cyp6a8 transcripts and the 1.8-kb RNA produced by the Cyp6a9 and/or Cyp6a9-related genes. Expression of the Cyp6a8 gene is down-regulated in the hybrids of 91-R and 91-C strains despite the fact that the hybrids carry one copy of the highly active allele of the Cyp6a8 gene of the 91-R strain. Based on these results we propose that the Cyp6a8 gene in 91-C strain may be turned off by an active repressor which might be inhibited by barbital treatment. In the 91-R strain, the putative repressor may be defective, allowing high level of constitutive expression of the Cyp6a8 gene.
Amino Acid Sequence↗
A 3.5-kb DNA fragment contains the cis-regulatory elements for retina-specific expression and partial dosage compensation of the Arrestin B (ArrB) gene of Drosophila miranda.
A 3.5-kb genomic DNA fragment containing the X1R chromosome-linked retina-specific Arrestin B gene (also called Arrestin 2) of Drosophila miranda (ArrB-mr) was introduced into the Drosophila melanogaster genome via germ-line transformation. The results showed that the ArrB-mr transgene was expressed only in the retina of the transformed flies. The transgene also showed male-specific transcriptional hyperactivation or dosage compensation, but the level was found to be 71-79% of the expected value. The endogenous autosomal ArrB-ml gene of D. melanogaster, as expected, was not found to be dosage compensated in the transformants. Thus, while the cis-regulatory elements for retina-specific expression are fully present in the 3.5-kb DNA, part of the sequences needed for full dosage compensation are missing in this DNA. Nucleotide (nt) sequence comparison of the upstream DNA revealed that both ArrB-mr and ArrB-ml possess a putative TATA box at -32 nt. They also have an 11-bp motif (5'-AATCCAGTTAG) similar to the photoreceptor conserved element I (PCE I) believed to play an important role in retina-specific expression of the D. melanogaster opsin and mouse Arr genes. In addition, both genes contain a TGACCT motif which is known to bind a transcription factor activated by retinoic acid and vitamin D3. However, five tandem repeats of a heptanucleotide sequence (TGGGCNR) and a 29-bp sequence with the potential to form a stem-loop structure, are found only in the ArrB-ml gene. These sequences may play an important role in dosage compensation of the X1R-linked ArrB-mr gene.
Animals↗
Organization and expression of the Drosophila melanogaster D-G gamma 1 gene encoding the G-protein gamma subunit.
The organization and expression of the Drosophila melanogaster G-protein gamma subunit-encoding gene (D-G gamma 1) were analyzed. The results showed that the three D-G gamma 1 RNAs (1.1, 1.3 and 2.6 kb) are differentially expressed in different tissues. While the 2.6-kb RNA is found only in the neural tissues of late embryo, larva and adult, the 1.3-kb RNA is expressed only in the adult ovary. The 1.1-kb RNA, on the other hand, is predominantly expressed during embryogenesis and in the neural tissues of late embryo, larva and adult. Moderate expression of this RNA is also found in the imaginal discs and other larval tissues. Nucleotide (nt) sequence analysis showed that the 70-amino-acid polypeptide encoded by the 1.3-kb transcript of D-G gamma 1 is the same as that encoded by the 1.1- and 2.6-kb D-G gamma 1 transcripts reported earlier [Ray and Ganguly, J. Biol. Chem. 267 (1992) 6086-6092]. Both the 1.3- and 1.1-kb RNAs utilize the same polyadenylation site, but their 3'-UTR are 1662 nt shorter than that of the 2.6-kb RNA. Although transcription of all three RNAs starts at the same transcription start point (tsp), the 5'-UTR of the 1.3-kb RNA is 190-nt longer than that of the other two RNAs, due to the utilization of an 3' alternative splice site.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Barriers to immunization--an examination of factors that influence the application of pneumococcal vaccine by house staff.
Pneumococcal infection is a leading cause of adult morbidity and mortality in the United States. Immunization against this infection is a valuable strategy in preventive medicine. An effective pneumococcal vaccine has been available in this country for over a decade, but it remains poorly utilized. The purpose of the present investigation was to analyse the factors that affect the use and administration of the pneumococcal vaccine and to identify barriers to use. Upper-level internal medicine residents (n = 33) from two medical clinics associated with an academic medical centre completed an explanatory survey. This explored the levels of house-staff knowledge, perception and attitudes regarding the vaccine and the existence of practical barriers against its utilization. chi 2 analyses and z tests were carried out to determine significance, where appropriate. The majority of the house staff (22, 66.7%) answered correctly regarding vaccine target groups, and all residents indicated that they generally obtain a vaccination history in adult patient evaluation. However, a sizeable number (14, 42.4%) did not indicate a time of the year when they routinely administered vaccines to patients. They were not confident about their knowledge regarding vaccine guidelines (23, 69.7%) and had an exaggerated fear of hypersensitivity reactions from immunization (20, 60.6%). Neither the expense of the vaccine nor adverse publicity were impediments to immunization (24, 72.7% and 28, 84.8%, respectively). Although most physicians knew of the usefulness of the vaccine (31, 93.9%), many failed to translate this knowledge into clinical practice (22, 66.7%). 'Pressing' clinical issues were viewed as barriers to vaccination (18, 54.5%) and placed the practice of preventive medicine in a subordinate position.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗