Biomedical subjects

S M Husain

Publications and source records attributed to S M Husain.

At least 19 recordsLinked to original sources

PubMed2006

Artificial perfusion of the fetal circulation of the in situ mouse placenta: methodology and validation.

Here we present methodology and validation (including measurement of unidirectional maternofetal clearance (Kmf) of (45)Ca and (14)C-mannitol) for in situ perfusion of the mouse placenta. On day 18 of gestation (term=19 days) mice were anaesthetised and the uterus delivered into a saline bath (40 degrees C). A fetus was selected, the umbilical artery and vein catheterised and perfused with Krebs Ringer (pH 7.4) at 60 microl/min. (45)Ca/(14)C-mannitol (2 microCi/5 microCi in 50 microl saline) was injected via maternal tail vein. Perfusate samples were collected every 5 min for 45 min. Maternal carotid artery pressure was monitored throughout perfusion. A terminal maternal cardiac blood sample was taken and analysed. Placentas were immersion fixed and processed for electron microscopy. Kmf for (45)Ca and (14)C-mannitol was calculated as perfusate [(45)Ca or (14)C-mannitol] x perfusion rate/maternal plasma [(45)Ca or (14)C-mannitol]xplacental weight. Maternal cardiac blood chemistry at termination (n=8-15, mean+/-SEM) was as follows: pH 7.153+/-0.016, PCO(2) 45.48+/-2.06 mmHg, PO(2) 66.47+/-7.10 mmHg, Na(+) 151.4+/-1.2 mmol/l, K(+) 5.54+/-0.17 mmol/l, Ca(2+) 1.15+/-0.03 mmol/l, glucose 7.2+/-0.5 mmol/l, and lactate 1.76+/-0.77 mmol/l. A successful 45 min perfusion in which perfusate recovery was >95% occurred in >50% of animals. Perfusion did not alter placental morphology or carotid pressure. Kmf (microl/min/g placenta) for (45)Ca (66.0+/-8.4 (n=7)) was significantly higher than Kmf for (14)C-mannitol (20.0+/-2.4 (n=5)) (p<0.01). These data demonstrate physiological perfusion of the mouse placenta in situ and its usefulness for measurement of solute transfer.

Animals↗

PubMed2006

Isolation, molecular cloning and in vitro expression of rhesus monkey (Macaca mulatta) prominin-1.s1 complementary DNA encoding a potential hematopoietic stem cell antigen.

Human prominin-1 (CD133 or AC133) is an important cell surface marker used to isolate primitive hematopoietic stem cells. The commercially available antibody to human prominin-1 does not recognize rhesus prominin-1. Therefore, we isolated, cloned and characterized the complementary DNA (cDNA) of rhesus prominin-1 gene and determined its coding potential. Following the nomenclature of prominin family of genes, we named this cDNA as rhesus prominin-1.s1. The amino acid sequence data of the putative rhesus prominin-1.s1 could be used in designing antigenic peptides to raise antibodies for use in isolation of pure populations of rhesus prominin-1(+) hematopoietic cells. To the best of our knowledge, there has been no previously published report about the isolation of a prominin-1 cDNA from rhesus monkey (Macaca mulatta).

AC133 Antigen↗

PubMed2005

Electrical potential difference between mother and conceptus in the mouse.

This study aimed to determine whether there is a maternofetal potential difference (PD) in the mouse. The mean (+/- SEM) in vivo electrical potential difference (PD(sa)) between saline filled catheters in the maternal subcutaneous space (s) and the fetal amniotic sac (a) measured, according to strict criteria, in anaesthetised MF1 mice at a gestational age of 18-20 (term 20) days was 3.9+/-0.5 mV (significantly different from zero P<0.0001) in 16 conceptuses from 11 mice with the amniotic sac positive with respect to the maternal catheter. The PD(sv) between maternal tail vein (v) and maternal subcutaneous space was -0.8+/-0.4 mV (n=3: not significantly different from zero). Measurement of PD between two different maternal subcutaneous catheters (n=4) was < or =0.5 mV. This study shows that there is a maternofetal PD in the mouse and provides the foundation for studies addressing its mechanism of generation in this species.

Amniotic Fluid↗

PubMed2001

Effect of diabetes mellitus on rat placenta cellularity.

Transcellular placental maternofetal flux of calcium and magnesium is reduced in diabetic pregnancy in the rat which might be due to changes in placental cellularity. In order to investigate this wet and dry weight, DNA and protein content were measured in placentas from untreated diabetic (D(O)), insulin-treated diabetic (D(I)) and control rats (C) on day 21 of gestation (term=23 days). Wet and dry weights (mg; mean+/-S.E.M.) were 418+/-13, 474+/-19, 416+/-14 and 66+/-3, 75+/-3, 67+/-3 in C, D(O) and D(I) groups, respectively. Total DNA and protein content (mg) was 1.8+/-0.2, 1.7+/-0.1, 1.5+/-0.1 and 50.4+/-2.4, 54.9+/-2.6, 51.9+/-3.3 in C, D(O) and D(I) groups, respectively. The data suggest that placental cellularity is unaffected by maternal diabetes mellitus in the rat and is unlikely to directly affect maternofetal flux of calcium and magnesium.

Animals↗

PubMed2001

Antigen expression during murine gamma-herpesvirus infection.

Gammaherpesviruses (gammaHV) establish a life-long latency in the host and are associated with a number of malignant human diseases. It is generally believed that T cells play a major role in controlling the initial acute infection and subsequently maintaining the virus in a quiescent state. However, the nature of the T cell response to gamma-herpesvirus infections is poorly understood. In the current report we took advantage of a mouse model of gammaHV infection (murine herpesvirus-68, MHV-68) to investigate the T cell response to different phases of the infection. Intranasal infection with MHV-68 induces an acute infection in lung epithelial cells and long-term latency in B cells. The kinetics of the CD8+ T cell response to different lytic cycle and latency-associated antigens was highly complex and distinct patterns of response could be identified. These responses were regulated by multiple factors including differences in temporal expression of the relevant antigens, differences in the presentation of antigen in different organs, and differential expression of antigen in different types of antigen presenting cells. For example, some antigens were expressed at distinct phases of the infection and in specific organs or subsets of antigen presenting cells. In addition, recent data suggest that in addition to B cells, both macrophages and dendritic cells harbor latent MHV-68 infection, adding further complexity to their role in controlling the T cell response to this infection.

Animals↗

PubMed2000

Latent murine gamma-herpesvirus infection is established in activated B cells, dendritic cells, and macrophages.

Intranasal infection of mice with the murine gamma-herpesvirus MHV-68 results in an acute lytic infection in the lung, followed by the establishment of lifelong latency. Development of an infectious mononucleosis-like syndrome correlates with the establishment of latency and is characterized by splenomegaly and the appearance of activated CD8+ T cells in the peripheral blood. Interestingly, a large population of activated CD8+ T cells in the peripheral blood expresses the V beta 4+ element in their TCR. In this report we show that MHV-68 latency in the spleen after intranasal infection is harbored in three APC types: B cells, macrophages, and dendritic cells. Surprisingly, since latency has not previously been described in dendritic cells, these cells harbored the highest frequency of latent virus. Among B cells, latency was preferentially associated with activated B cells expressing the phenotype of germinal center B cells, thus formally linking the previously reported association of latency gene expression and germinal centers to germinal center B cells. Germinal center formation, however, was not required for the establishment of latency. Significantly, although three cell types were latently infected, the ability to stimulate V beta 4+CD8+ T cell hybridomas was limited to latently infected, activated B cells.

Animals↗

PubMed2000

Effects of acute maternal hyperglycaemia and hyperosmolality on maternofetal transfer of calcium and magnesium across the in situ perfused rat placenta.

The effects of acute maternal hyperglycaemia and hyperosmolality on maternofetal placental transfer of Ca, Mg and 51Cr-EDTA were investigated in the rat. On day 21 of gestation (term = 23 d) the fetal circulation of the in situ placenta of anaesthetised rats was perfused with a Mg-free Krebs Ringer solution and the unidirectional maternofetal fluxes of Ca (CaJmf) and Mg (MgJmf), and the unidirectional maternofetal clearance of 51Cr-EDTA ((EDTA)Kmf) were determined before and during maternal hyperglycaemia, hyperosmolality and volume expansion, attained by infusing 30% D-glucose, 25% mannitol and 0.9% saline solutions, respectively, into the maternal circulation. MgJmf was significantly reduced during glucose infusion (23.9 +/- 1.2 v 28.2 +/- 1.4 nmol min(-1) g(-1) placenta during control perfusion (mean +/- SEM); p < 0.005) and during mannitol infusion (28.2 +/- 1.0 v 33.5 +/- 1.5 nmol min(-1) g(-1) placenta; p < 0.001). CaJmf and (EDTA)Kmf were not significantly altered by maternal hyperglycaemia or hyperosmolality. There was no significant change in MgJmf during infusion of saline into the maternal circulation. Maternal plasma Na concentration was significantly reduced in both glucose and mannitol infusion experiments, whereas maternal plasma Mg concentration was significantly reduced only during glucose infusion. We postulate that the reduced maternal plasma Na concentration in the glucose and mannitol experiments might decrease MgJmf via alteration of placental Na+/Mg2+ exchange activity.

Animals↗

PubMed1999

Murine gammaherpesvirus M2 gene is latency-associated and its protein a target for CD8(+) T lymphocytes.

Murine gammaherpesvirus 68 (MHV-68) infection of mice is a potential model with which to address fundamental aspects of the pathobiology and host control of gammaherpesvirus latency. Control of MHV-68 infection, like that of Epstein-Barr virus, is strongly dependent on the cellular immune system. However, the molecular biology of MHV-68 latency is largely undefined. A screen of the MHV-68 genome for potential latency-associated mRNAs revealed that the region encompassing and flanking the genomic terminal repeats is transcriptionally active in the latently infected murine B-cell tumor line S11. Transcription of one MHV-68 gene, that encoding the hypothetical M2 protein, was detected in virtually all latently infected S11 cells and in splenocytes of latently infected mice, but not in lytically infected fibroblasts. Furthermore, an epitope was identified in the predicted M2 protein that is recognized by CD8(+) T cells from infected mice and a cytotoxic T lymphocyte line that recognizes this epitope killed S11 cells, indicating that the M2 protein is expressed during latent infection and is a target for the host cytotoxic T lymphocyte response. This work therefore provides essential information for modeling MHV-68 latency and strategies of immunotherapy against gammaherpesvirus-related diseases in a highly tractable animal model.

Animals↗

PubMed1999

Urinary excretion of pyridinium crosslinks in healthy 4-10 year olds.

Urinary pyridinoline and deoxypyridinoline, pyridinium crosslinks released during breakdown of mature collagen, might serve as useful markers of bone resorption. Before their role can be identified, reference values must be established. In this study, free pyridinoline (f-Pyr), free deoxypyridinoline (f-DPyr), and creatinine (Cr) were measured in first morning void urine samples from 250 girls and 265 boys between the ages of 4 and 10 years. Overall, there was a decrease in f-Pyr:Cr and f-DPyr:Cr ratios with increasing age in both sexes, but there was a wide range of values for individuals of similar ages. Further studies are required to assess whether urinary pyridinium crosslink excretion is sufficiently deranged in conditions affecting bone metabolism for the measurement of these compounds to be of clinical value.

Age Factors↗

PubMed1995

The effect of diabetes mellitus on urinary calcium excretion in pregnant rats and their offspring.

The effect of maternal diabetes mellitus on renal calcium excretion in pregnant rats and their offspring has been examined in order to ascertain the role of the kidney in the disturbed calcium homeostasis of infants born to diabetic mothers. Diabetic pregnant (DP) rats exhibited severe hypercalciuria which greatly exceeded the urinary calcium losses (UCaV) in non-diabetic pregnant (CP) or non-pregnant diabetic (D) rats. Means +/- S.E.M. for UCaV at day 21 (mmol/24 h) were: DP = 1.12 +/- 0.09 (n = 7); CP = 0.06 +/- 0.01 (n = 7); D = 0.63 +/- 0.06 (n = 7) (P < 0.001 DP vs CP and DP vs D). The profile for urinary calcium excretion in the three groups was different from that of other measured ions. The degree of natriuresis, for example, was comparable in DP and D rats at all stages studied. Although magnesium output was significantly greater in DP than D rats on days 14 and 21, this appeared to result from an additive effect of the magnesiuresis seen when pregnancy and diabetes were studied separately. The marked renal calcium wasting of diabetic pregnancy will have implications for overall calcium balance in the mother. For example, an enhanced intestinal calcium absorption was seen in DP rats in the second half of gestation. Means +/- S.E.M. for day 21 (mmol/24 h) were: DP = 3.8 +/- 0.8 (n = 7); CP = 1.4 +/- 0.3 (n = 7); D = 1.6 +/- 0.3 (n = 7) (P < 0.05 DP vs CP and DP vs D).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1995

Analysis of sickle cell gene using polymerase chain reaction & restriction enzyme Bsu 361.

A 772bp DNA fragment from human beta-globin gene has been amplified by polymerase chain reaction (PCR) and subjected to restriction enzyme analysis using Bsu 361, an isoschizomer of restriction enzyme Mst II. This protocol has been designed basically to enhance the analytical facility for the detection of sickle cell mutation. A 430bp DNA fragment was found to be associated with the mutant locus, whereas 228bp and 202bp DNA fragments were generated from the normal locus. This difference of about 202bp in the resulting fragments from the mutant and normal loci has improved discriminatory power in the genotype analysis of the sickle cell mutation.

Anemia, Sickle Cell↗

PubMed1994

Effect of diabetes mellitus on maternofetal flux of calcium and magnesium and calbindin9K mRNA expression in rat placenta.

The effect of maternal diabetes mellitus on placental unidirectional maternofetal flux of calcium (Ca) and magnesium (Mg), calbindin9K mRNA expression, and net fetal Ca and Mg accretion has been investigated using control (C), untreated diabetic (D(O)) and insulin-treated diabetic (DI) rats. Unidirectional maternofetal flux of Ca in the D(O) group was 61 and 63% of the value of the C and DI groups; unidirectional maternofetal flux of magnesium in the D(O) group was 79 and 66% of the value in the C and DI groups. Fetal Ca and Mg content (mmol; mean +/- SEM) was also significantly lower in the D(O) group compared with the other two groups (0.111 +/- 0.004 versus 0.153 +/- 0.008 in C and 0.168 +/- 0.007 in DI, p < 0.01 D(O) versus C and DI for Ca; and 0.021 +/- 0.001 versus 0.027 +/- 0.001 in C and 0.031 +/- 0.001 in DI, p < 0.01 D(O) versus C and DI for Mg). However, only Ca content was significantly lower in the D(O) group when normalized to fetal ash weight. Densitometric analysis of autoradiograms after Northern hybridization with cDNA probes demonstrated that the placental calbindin9K/cyclophilin mRNA ratio was 11- to 12-fold lower in the D(O) group compared with the C and DI groups. Collectively, the data suggest that untreated maternal diabetes mellitus reduces fetal Ca and Mg accretion by an effect on the expression of placental transport components involved in the maternofetal transfer of these cations.

Amino Acid Isomerases↗

PubMed1993

Measurement of ionised calcium concentration in neonates.

Whole blood ionised calcium concentration was measured simultaneously in capillary and arterial blood from neonates being nursed on an intensive care unit using an ion selective electrode. The mean arterio-capillary difference was -0.027 mmol/l (95% confidence intervals -0.041 to -0.012 mmol/l) and the limits of agreement between the two measurements were 0.034 and -0.088 mmol/l. Measurement of ionised calcium in capillary blood is acceptable for clinical purposes.

Arteries↗

PubMed1993

Magnesium and pregnancy.

Maternal and fetal magnesium homeostasis is reviewed. Current evidence suggests that pregnancy-associated growth is unlikely to cause maternal magnesium deficiency and that the case for magnesium supplementation during pregnancy is unproven. Similarly, data do not support the use of magnesium in prevention of preterm labor or its preferential use in tocolysis. Magnesium might have a role to play in the prevention/treatment of eclamptic seizures. Hypomagnesaemia occurs in poorly controlled diabetic pregnancy and may be part of the cause of the hypomagnesaemia in the infants of such mothers. Fetal magnesium homeostasis is poorly understood as is the mechanism of placental transfer. Data from the rat suggest that the bulk of maternofetal placental magnesium transfer occurs via a transcellular route utilising a Na+/Mg2+ exchanger and that maternofetal flux of magnesium is reduced in the presence of maternal diabetes mellitus. Further study of diabetic pregnancy will increase our understanding of magnesium homeostasis both in normal and abnormal pregnancy.

Animals↗

PubMed1992