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Biomedical subjects

S Jahan

Publications and source records attributed to S Jahan.

17 recordsLinked to original sources
PubMed2007

Neuroendocrine regulation of prolactin secretion in adult female rhesus monkeys during different phases of the menstrual cycle: role of neuroexcitatory amino acid (NMA).

The present study attempts to examine the role of N-methyl-D, L-aspartate (NMDA) receptors in the central regulation of prolactin (PRL) secretion, which may be involved in ovarian function and its alteration by glutamate in various phases of the menstrual cycle of female rhesus monkeys (Macaca mulatta). The results suggest that the glutaminergic component of the control system, which governs PRL secretion by utilizing NMDA receptors, may have an important role in regulating changes in PRL secretion. The response of PRL during the luteal phase of the cycle was different from that observed in follicular and menstrual phases. Steroids may influence the NMDA-dependent drive to release PRL. N-methyl-D-aspartic acid (NMA) involvement in the regulation of PRL secretion may occur through activation of the PRL-stimulating system depending on the physiological state or steroidal milieu. It is possible, therefore, that the NMA-induced release of PRL-releasing factors (PRF) and PRL are enhanced in the presence of ovarian feedback.

Analysis of Variance↗
PubMed2000

Increased concentrations of plasma neuropeptide Y in patients with eclampsia and preeclampsia.

OBJECTIVE: Epinephrine and norepinephrine are associated with the hyperstimulation of the sympathetic nervous system. Neuropeptide Y is a potent vasoconstrictive substance that is released in response to sympathetic nerve stimulation. STUDY DESIGN: The concentrations of plasma neuropeptide Y in pregnant patients with eclampsia (n = 8), preeclampsia (n = 8), and normotension (n = 8) were measured by radioimmunoassay on admission and 6 days after delivery. Correlations between plasma concentration of neuropeptide Y and mean arterial blood pressure were also evaluated in these patients on admission and 6 days after delivery. RESULTS: The plasma level of neuropeptide Y in women with eclampsia (P <.001) and preeclampsia (P <.003) was found to be significantly elevated with respect to that in normotensive pregnant women. At 6 days after delivery the concentration of plasma neuropeptide Y was significantly decreased in women with eclampsia, women with preeclampsia, and women with normotensive pregnancies compared with the value measured on admission (P <.0001, P <.0001, and P <.002, respectively). At admission the plasma neuropeptide Y level was positively correlated with mean arterial blood pressure in women with eclampsia and preeclampsia. However, no significant correlations were observed between plasma neuropeptide Y concentration and mean arterial blood pressure both at admission and 6 days after delivery in normotensive pregnant women and 6 days after delivery in women with eclampsia and preeclampsia. CONCLUSION: We have concluded that the level of neuropeptide Y in plasma is increased in women with eclampsia and preeclampsia. Elevated plasma neuropeptide Y levels may play a key role in the development of eclampsia and preeclampsia.

Adult↗
PubMed1998

Microbial transformations of hypolipemic E-guggulsterone.

Biotransformation of E-guggulsterone (pregna-4,17(20)-cis-diene-3,16-dione) (1) by Aspergillus niger resulted in the formation of four new hydroxyl derivatives identified as 7 beta-hydroxypregna- 4,17(20)-trans-diene-3,16-dione (2), 7 beta-hydroxypregna-4,17(20)-cis-diene-3,16-dione (3), 7 beta- hydroxypregn-4-ene-3,16-dione (4), and 7 beta,15 beta-dihydroxypregn-4-ene-3,16-dione (5). The biotransformation of 1 with Cephalosporium aphidicola also resulted in the formation of four new steroidal derivatives as 11 alpha-hydroxypregna-4,17(20)-trans-diene-3,16-dione (6), 11 alpha- -hydroxypregna-4,17(20)-cis-diene-3,16-dione (7), 11 alpha,15 beta-dihydroxypregna-4,17(20)-trans-diene- 3,16-dione (8), and 11 alpha,15 beta-dihydroxypregna-4,17(20)-cis-diene-3,16-dione (9). The structures of these compounds were elucidated on the basis of 1D and 2D NMR spectroscopic techniques.

Anti-Bacterial Agents↗
PubMed1998

Modified preparation and rapid quality control test for technetium-99m-tetrofosmin.

OBJECTIVE: The objectives of this study were to: modify the preparation of 99mTc-tetrofosmin by using twice the amount of 99mTcO4- recommended by the manufacturer; evaluate the use of miniaturized rapid paper chromatography (MRPC) for quality control (QC) testing; and determine the in vitro stability of the modified preparation using MRPC. METHODS: Two preparations of 99mTc-tetrofosmin were made: one with 4.4-8.8 GBq (120-240 mCi) and the other with 13.9-17.6 GBq (380-480 mCi) 99mTcO4-, referred to as regular and modified preparations, respectively. Routine QC tests were performed using MRPC and instant thin-layer chromatography/silica-gel (ITLC/SG) systems. The preparations were injected into 58 patients. Planar and SPECT images of stress and rest studies were obtained. The technical quality of the SPECT images was graded visually by four observers. Heart-to-lung and heart-to-background ratios were calculated from the planar images. RESULTS: The QC testing procedure took 4.18 +/- 0.15 min with MRPC and 54 +/- 5.3 min with ITLC/SG systems. The percent labeling efficiency, as determined by both techniques, ranged from 95.6 +/- 1.6 to 97.2% +/- 0.8%. Both preparations were stable up to 6 hr after reconstitution. There was no difference between the cardiac-to-lung and cardiac-to-background ratios of the two preparations. CONCLUSION: The results indicate that MRPC is a faster and effective chromatographic technique for routine QC testing of 99mTc-tetrofosmin. Doubling the amount of 99mTcO4- used in preparing 99mTc-tetrofosmin did not affect its in vitro stability, its efficacious use in patients or the technical quality of the images.

Chromatography, Paper↗
PubMed1997

Increased concentrations of plasma epinephrine and norepinephrine in patients with eclampsia.

We measured plasma catecholamine concentrations on admission (after eclamptic fit) and after 6 days of delivery in 21 eclamptic patients and on admission in 15 normotensive pregnant women in Bangladesh. Plasma epinephrine and norepinephrine concentrations in eclamptic patients were significantly higher on admission than those of normotensive pregnant women (P < 0.0001). Plasma catecholamine concentrations and mean arterial blood pressure had return to be almost normal as normotensive pregnant women after 6 days of delivery, resulting in no correlation between mean arterial blood pressure and plasma catecholamines. On admission (after eclamptic fit) mean arterial blood pressure was positively correlated with plasma epinephrine (r = 0.626, P < 0.002) and norepinephrine (r = 0.553, P < 0.008) concentrations in patients with eclampsia. The amount of proteinuria was also significantly correlated with plasma epinephrine (r = 0.515, P < 0.02) and norepinephrine (r = 0.606, P < 0.003) concentrations. Number of convulsions was significantly correlated with concentrations of plasma epinephrine (r = 0.514, P < 0.02), norepinephrine (r = 0.521, P < 0.01) and mean arterial blood pressure (r = 0.535, P < 0.01). A positive correlation was found between time passed after convulsion with plasma epinephrine (r = 0.515, P < 0.02) and norepinephrine (r = 0.570, P < 0.006) concentrations. These suggested that the increased plasma levels of epinephrine and norepinephrine in eclamptic patients were well correlated with the severity of the clinical features of eclampsia.

Bangladesh↗
PubMed1996

Increased concentrations of plasma epinephrine and norepinephrine in patients with eclampsia.

We measured plasma catecholamine concentrations on admission (after eclamptic fit) and after 6 days of delivery in 21 eclamptic patients and on admission in 15 normotensive pregnant women in Bangladesh. Plasma epinephrine and norepinephrine concentrations in eclamptic patients were significantly higher on admission than those of normotensive pregnant women (P < 0.0001). Plasma catecholamine concentrations and mean arterial blood pressure had return to be almost normal as normotensive pregnant women after 6 days of delivery, resulting in no correlation between mean arterial blood pressure and plasma catecholamines. On admission (after eclamptic fit) mean arterial blood pressure was positively correlated with plasma epinephrine (r = 0.626, P < 0.002) and norepinephrine (r = 0.553, P < 0.008) concentrations in patients with eclampsia. The amount of proteinuria was also significantly correlated with plasma epinephrine (r = 0.515, P < 0.02) and norepinephrine (r = 0.606, P < 0.003) concentrations. Number of convulsions was significantly correlated with concentrations of plasma epinephrine (r = 0.514, P < 0.02), norepinephrine (r = 0.521, P < 0.01) and mean arterial blood pressure (r = 0.535, P < 0.01). A positive correlation was found between time passed after convulsion with plasma epinephrine (r = 0.515, P < 0.02) and norepinephrine (r = 0.570, P < 0.006) concentrations. These suggested that the increased plasma levels of epinephrine and norepinephrine in eclamptic patients were well correlated with the severity of the clinical features of eclampsia.

Adult↗
PubMed1995

A miniaturized rapid paper chromatographic procedure for quality control of technetium-99m sestamibi.

A miniaturized rapid paper chromatographic technique (MRPC) for quality control of a technetium-99m sestamibi preparation was developed and compared with the manufacturer's and Hung et al. techniques. The MRPC system involves the use of 6.0x0.5cm Whatman 3MM paper strip developed in ethyl acetate. The procedure was completed within 3min while that of the manufacturer and Hung techniques took 30-35 and 4min respectively. The Rf range of 99mTc-sestamibi using MRPC was 0.55-0.75 while that of the other two techniques was 0.9-1.0. The results indicate that MRPC can be used to separate 99mTc-sestamibi from any 99mTc contaminant that migrates with the solvent front. The MRPC is a fast and effective chromatographic technique for routine quality control testing of 99mTc-sestamibi preparation.

Chromatography, Paper↗
PubMed1991

Possible modulation of N-methyl-D,L-aspartic acid induced prolactin release by testicular steroids in the adult male rhesus monkey.

N-methyl-D,L-aspartic acid (NMA), an agonist of the neurotransmitter glutamate has been shown to acutely stimulate the release of prolactin (PRL) in intact rats and monkeys. To further investigate the role of neuroexcitatory amino acids in PRL secretion, the effects of NMA administration were examined on PRL release in long term orchidectomized adult rhesus monkeys, in both the absence and presence of testosterone. Intact and long term castrated adult male monkeys weighing between 8-13 kg, were implanted with a catheter via the saphenous vein for blood withdrawal and drug infusion. Blood samples were collected at 10 min intervals for 50 min before and 70 min after administration of the drug or vehicle. Plasma PRL concentrations were estimated using radioimmunoassay. Whereas a single iv injection of NMA (15 mg/kg BW) induced a prompt discharge of PRL in intact monkeys, an identical dose had surprisingly no effect on PRL secretion in orchidectomized animals. On the other hand, plasma PRL increases in response to a challenge dose of thyrotropin releasing hormone (TRH; 6 micrograms/kg BW, iv) were similar in magnitude in the two groups of monkeys. Testosterone replacement in orchidectomized animals by parenteral administration of testosterone enanthate (200 mg/wk) reinitiated the PRL responsiveness to acute NMA stimulation. These results indicate that N-methyl-D-aspartic acid (NMDA) dependent drive to PRL release in the adult male rhesus monkey may be overtly influenced by the sex steroid milieu.

Animals↗
PubMed1990

Cerebral perfusion changes in schizophrenic patients using Tc-99m hexamethylpropylene amineoxime (HMPAO).

Tc-99m hexamethylpropylene amineoxime (HMPAO) was used to image cerebral perfusion changes in 20 patients with chronic schizophrenia (19 male and 1 female, aged 22-48, at an average age of 29.0). All were being given neuroleptic drugs. Twelve had electroconvulsive therapy. In addition, all had abnormal studies except one, who was normal and had a poor response to treatment. Ventricular dilatation and cerebral atrophy was seen in eleven patients, and 77 focal lesions were detected. Forty-two lesions demonstrated increased HMPAO retention, which was distributed as follows: 26 in the basal ganglia in 14 patients (12 bilateral, 2 unilateral); 10 along the sylvian fissure in the parietotemporal region; and 3 in the frontal and 1 in each of the temporal, parietal, and occipital regions. Thirty-five focal lesions exhibited decreased perfusion: ten parietal, eight frontal, seven temporal, six cerebellar, and four occipital lobes. This study demonstrates the potential value of Tc-99m HMPAO in schizophrenia and other psychiatric disorders.

Adult↗
PubMed1989

Effect of dexamethasone on the estrous cycle length in Black Bengal goats (Capra hircus ).

In an experiment to examine the relationships between adrenals and reproductive cycle, 10 mg dexamethasone (a synthetic glucocorticoid) were injected intramuscularly twice daily for 10 d to four Black Bengal goats, beginning on Day 11 of the synchronized estrous cycle. The extended length of the sexual cycle was monitored by the clinical signs of anestrus. Laparotomy was performed to examine the status of the ovary of an 8, 9, 10 and 8 d extended cycle, respectively. The length of the next cycle was normal. Endogenous cortisol values were suppressed for 11, 13, 20 and 24 d, respectively. It is thought that dexamethasone caused prolonged luteal function either by the suppression of prostaglandin F(2)alpha synthesis or by the suppression of pituitary stimulation of follicular growth.

Journal Article↗
PubMed1989

Role of thallium-201 in the diagnosis of solitary bone lesions.

Thallium-201 is known to accumulate in malignant tumours. In this work we are evaluating the role of thallium in differentiating benign from malignant solitary bone lesions in 28 patients with solitary bone lesions on 99Tcm-MDP bone scans. Lesions' uptake of 201Tl was evaluated using visual assessment and lesion to background ratio. We found significant uptake with a mean lesion to background ratio of 4.27 in malignant lesions and no or faint uptake with a mean lesion to background ratio of 1.37 in benign lesions.

Adolescent↗
PubMed1985

Congenital absence of the mammary gland.

Tc-99m pertechnetate is known for its uptake and excretion by the mammary gland. Generally, lactating women are not advised to have any radioisotopic studies. If it is necessary to have one, it is recommended that they do not breast-feed their children for at least 24 hours. Congenital absence of the mammary gland is a rare condition. This case was accidently discovered. Nuclear medicine physicians should be aware of the value of clinical examination of patients, and that not every absent or asymmetric breast shadow is due to surgical resection.

Adult↗
PubMed1984

Liver metastasis from embryonal carcinoma of the ovary with complete situs inversus. First reported case and review of literature.

Embryonal carcinoma of the ovary in a 17-year-old Saudi girl with complete situs inversus is reported. According to reports since 1936, this is the sixteenth case of cancer associated with complete situs inversus, the second ovarian cancer, the first embryonal carcinoma of the ovary, and the youngest cancer case to be reported in association with this congenital anomaly.

Adolescent↗