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Abstract
Epibatidine has been shown to be the most potent nicotinic agonist in several neuronal nicotinic receptor preparations. Similar to other nicotinic agonists, intrathecal (-)-epibatidine elicits dose-dependent increases in pressor, heart rate and pain responses in rats, as well as an increase in latency to withdraw from a noxious thermal stimulus. The latter response requires higher doses and is of shorter duration, suggesting interaction with multiple subtypes of spinal nicotinic receptors. In the present study, we relate the binding properties of (+/-)-[3H]epibatidine in spinal cord membrane preparations to the cardiovascular and behavioral responses. Unlike (-)-[3H]cytisine or (-)-[3H]nicotine, (+/-)-[3H]epibatidine reveals two sites; the ratio of high affinity to low affinity sites is 2:1. The rank ordering of potencies of the nicotinic agonists in displacing (+/-)-[3H]epibatidine binding from spinal cord membranes correlates with the potencies in eliciting cardiovascular and behavioral responses upon spinal administration. The nicotinic receptor antagonists, alpha-lobeline, dihydro-beta-erythroidine and methyllycaconitine, also displayed similar rank ordering of potencies in displacing (+/-)-[3H]epibatidine, (-)-[3H]cytisine or (-)-[3H]nicotine binding to spinal nicotinic receptors. Virtually all the nicotinic analogs exhibited a Hill coefficient of less than one in competing with (+/-)-[3H]epibatidine to spinal cord membranes indicating their interaction with at least two classes of binding sites. Intrathecal (-)-epibatidine, in addition to eliciting an initial and subsequently a sustained pressor and tachycardic response, also exhibited a transient intervening bradycardia which coincided temporally with the duration of the analgesia. Repeated administration of (-)-epibatidine desensitized its responses as well as the cardiovascular and behavioral responses to spinal nicotine and cytisine. Intrathecal alpha-lobeline showed selectivity for blocking the analgesic response, whereas methyllycaconitine exhibited selectivity for the pressor and irritation responses. The NMDA receptor antagonist, AP-5, inhibited the pressor, tachycardic and irritation responses elicited by intrathecal (-)-epibatidine, confirming a role for spinal excitatory amino acids released by the nicotinic agonist.
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Khan IM, Youngblood KL, Printz MP, Yaksh TL, Taylor P. Spinal nicotinic receptor expression in spontaneously hypertensive rats. Hypertension 1996; 28:1093-9. [PMID: 8952602 DOI: 10.1161/01.hyp.28.6.1093] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Intrathecal administration of nicotinic agonists previously has been shown to result in exaggerated pressor and heart rate responses as well as greater nociceptive behavior in adult (12-week-old) spontaneously hypertensive rats (SHR) than in age-matched normotensive Wistar-Kyoto rats (WKY). Paradoxical to these augmented responses to nicotinic agonists in SHR, nicotinic receptor number in the spinal cord as measured by cytisine binding sites is lower in adult SHR than normotensive WKY and Sprague-Dawley rats. Using the high-affinity agonist epibatidine, we found similar differences in receptor number between strains in both in vitro ligand binding experiments with spinal cord membranes and in situ autoradiographic analyses. Spinal nicotinic receptor number did not differ in 5-week-old prehypertensive SHR and age-matched WKY; however, receptor numbers were higher in young rats of both strains than in their adult counterparts. Antihypertensive treatment (25 mg/kg per day hydralazine PO) in 6-week-old SHR from 6 to 12 weeks of age markedly reduced the progressive rise in blood pressure yet did not alter nicotinic receptor number compared with untreated rats. Similar treatment of WKY with hydralazine produced a slight fall in blood pressure but no change in receptor number. Thus, normalization of blood pressure by hydralazine in SHR does not result in a return of receptor expression to levels seen in normotensive rats. Higher centrally mediated pressor activity or augmented postcoupling events after neuronal nicotinic receptor stimulation may slowly downregulate expression of spinal nicotinic receptors in this genetically hypertensive rat strain.
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Abstract
Some 114 patients (median age 52 years) underwent laparoscopic hernia repair as a day-case procedure. Twenty-one patients had bilateral and 11 recurrent hernias. Some 113 patients underwent transabdominal preperitoneal mesh repair but one required conversion to open operation. Mean operating time was 24 min for unilateral and 38 min for bilateral repair. In an operating session of 3.5 h, up to five patients (mean 4.4) underwent surgery and as many as seven hernias were repaired. More than 10 per cent of patients were found to have a previously undiagnosed hernia on the opposite side. A total of 111 patients were discharged home on the day of surgery. Major complications included one omental bleed and one small bowel obstruction. Seroma was the commonest minor complication and occurred in 7 per cent of patients. More than 35 per cent of patients needed no postoperative analgesia. To date there has been one recurrence (follow-up range 2-18 months).
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Khan IM, Marsala M, Printz MP, Taylor P, Yaksh TL. Intrathecal nicotinic agonist-elicited release of excitatory amino acids as measured by in vivo spinal microdialysis in rats. J Pharmacol Exp Ther 1996; 278:97-106. [PMID: 8764340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The nicotinic agonists, nicotine and cytisine, when administered intrathecally elicit an increase in blood pressure and heart rate as well as a nociceptive response. By using a novel microdialysis procedure, in which a 4-cm dialysis tubing is inserted proximal to the intrathecal injection site, we have examined the release of excitatory amino acids associated with agonist stimulation. The nicotinic agonists, nicotine, cytisine and epibatidine, elicit dose-dependent increases in spinal release of Asp and Glu. The rank order of potencies of the nicotinic agonists in eliciting the cardiovascular and irritation responses correlates with the order of agonist potency in inducing Asp and Glu release in spinal microdialysates. In addition, a correlation is observed between the nociceptive and blood pressure response evoked by the nicotinic agonists and the spinal release of the excitatory amino acids. By examining the position of the permeable dialysis surface in relation to the agonist injection port, we found that the response to nicotine is localized to 5 to 10 mm distances, whereas the cytisine response may be elicited over longer distances. The marked desensitization observed upon repeated administration of cytisine is also reflected in diminished amino acid release. Amino acid release by nicotine can be antagonized by a channel blocking antagonist, mecamylamine, and by a competitive antagonist, dihydro-beta-erythroidine. Mecamylamine also inhibited the amino acid release elicited by epibatidine and cytisine. Hence, excitatory amino acid release is an appropriate response marker for the cellular events associated with nicotinic receptor stimulation in the spinal cord.
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Farrell RJ, Noonan N, Khan IM, Goggins M, Kelleher DP, Keeling PW. Carcinoma of the ampulla of Vater: a tumour with a poor prognosis? Eur J Gastroenterol Hepatol 1996; 8:139-44. [PMID: 8723418 DOI: 10.1097/00042737-199602000-00009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVE To assess the overall prognosis of patients with ampullary carcinomas and evaluate the presentation, diagnosis, pathology and management of these potentially highly curable tumours, attempting to relate these factors to overall survival. PATIENTS AND METHODS Forty patients with ampullary carcinoma were reviewed. Age, Sex, nature and duration of history, laboratory information at admission, results of diagnostic radiology, endoscopic retrograde cholangiopancreatograms and pathological findings were considered. Both curative and palliative management strategies were reviewed. RESULTS The overall median survival was 19 months. The median duration of history was 5.9 +/- 5.4. weeks, with no significant difference in survival between patients with short and those with long histories (P = 0.46). Twenty nine (73%) patients were potentially resectable, but only 15 (37%) underwent potentially curative surgery. The difference in survival between the Whipple's (13) and the endoscopically stented (20 ) groups was not significant (p = 0.08). The Whipple's group were significantly younger than the stented group (P = 0.001) and had a significant operative morbidity, re-operation rate (38%) and post-operative mortality (15%). Only five of 13 patients were alive following Whipple's treatment after a mean follow-up of 18.9 months. Sphincterotomy before Whipple's treatment improved survival significantly (P = 0.04); absence of jaundice, exophytic macroscopic appearance, well-differentiated tumours and early stage were also associated with good survival. Endoscopic retrograde cholangiopancreatography has a high diagnostic yield and a low associated morbidity and mortality, with endoscopic papillectomy aiding cannulation while effective palliation was provided through stenting, endoscopic papillectomy and laser debulking of obstructing tumours. Little benefit was obtained from chemoradiotherapy. CONCLUSION Despite the potential for curative resection in patients with ampullary carcinoma, the majority of such patients are unsuitable for curative surgery on grounds of age, general health status or advanced disease; since only 37% of patients undergo potentially curative surgery the condition has a poor prognosis.
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Soteriou B, Fisher RA, Khan IM, Kessling AM, Archard LC, Buluwela L. Conserved gene sequences for species identification: PCR analysis of the 3' UTR of the SON gene distinguishes human and other mammalian DNAs. Forensic Sci Int 1995; 73:171-81. [PMID: 7657183 DOI: 10.1016/0379-0738(95)01748-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In this paper we show that the polymerase chain reaction (PCR) can be used on regions of highly conserved genes, such as the 3' untranslated region (3' UTR) of the SON gene, to identify the mammalian origin of a sample. Using this test, we have been able to distinguish human, monkey, cat, dog, mouse and hamster DNAs. We have also determined the DNA sequence of these different PCR products, which can be used to reinforce species identification. The advantages of this test are that: (i) no prior information is required on the possible species origin of a sample, (ii) the reaction produces a single PCR product which varies in size according to the species of origin, making the test simple to interpret, and (iii) the target region of DNA amplified in these experiments is small and can easily be sequenced and sized using automated techniques. This small size has enabled us to successfully amplify this product from DNA extracted from compromised material (human bone samples) and so demonstrate that the test is valuable for the characterisation of remains in which DNA is degraded.
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Khan IM, Miller DH, Strickland J, Margolius HS, Privitera PJ. Brain kallikrein-kinin system abnormalities in spontaneously hypertensive rats. Hypertension 1995; 25:524-30. [PMID: 7721393 DOI: 10.1161/01.hyp.25.4.524] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The objective of the present study was to determine whether the brain kallikrein-kinin system differs between spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY) and if so, whether any detected differences occur before the development of hypertension in SHR. We measured cerebrospinal fluid levels of various components of the system in adult and young prehypertensive SHR and WKY. Cerebrospinal fluid kinin concentration and appearance rate were higher in SHR. Cerebrospinal fluid active kallikrein level and kininogenase activity were also higher in adult SHR. In addition, cerebrospinal fluid kinin concentration and appearance rate were higher in prehypertensive, 5- to 6-week-old SHR compared with age-matched WKY. However, no differences in cerebrospinal fluid kallikrein or kininogenase activity were observed between the two strains of young rats. Cerebrospinal fluid kinin concentration was higher in young versus adult rats of the same strain. In WKY, cerebrospinal fluid kallikrein also decreased with age although cerebrospinal fluid kallikrein concentration did not decrease in young and adult SHR. Together, these data suggest that there is a hyperactive kallikrein-kinin system in the brain of SHR that may contribute to the hypertensive state in this animal model.
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Khan IM, Taylor P, Yaksh TL. Stimulatory pathways and sites of action of intrathecally administered nicotinic agents. J Pharmacol Exp Ther 1994; 271:1550-7. [PMID: 7996469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Intrathecal (i.t.) administration of nicotinic agonists to rats elicits a receptor-mediated pressor response, a heart rate increase and irritation-nociceptive behavior. We examined the stimulatory pathways and sites of action of spinally administered nicotinic agonists. The thoracic region appears more sensitive to nicotine-elicited pressor actions than the lumbar or cervical regions of the spinal cord. Nicotinic receptors evoking a nociceptive response appear to be located over an area extending from the lumbar rostrally to the thoracic region. Similar to the pressor response, the thoracic spinal cord is the most sensitive region to nicotine in producing the heart rate increase. The cervical region is the least responsive to nicotine, suggesting sites of actions caudal to the brain stem. Intravenous infusion of trimethaphan inhibited the nicotine-elicited pressor response and tachycardia without affecting the irritation response. This suggests that the cardiovascular responses to spinal nicotinic agonists result from enhanced sympathetic outflow. Intrathecal morphine and MK-801 block spinal nicotine-elicited irritation and tachycardia but not the pressor response, indicating that pressor and irritation responses involve independent receptor-mediated pathways. Tachycardia may be associated with the irritation response. In contrast to nicotine, both pressor and irritation responses to cytisine were blocked by morphine with no effect on heart rate. Spinal transection at the T1-2 level eliminated the nociceptive response to nicotine but not the pressor response. Cytisine responses were similar to nicotine; however, cytisine was significantly less potent as a pressor agent in the transected compared with intact animals.(ABSTRACT TRUNCATED AT 250 WORDS)
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Khan IM, Printz MP, Yaksh TL, Taylor P. Augmented responses to intrathecal nicotinic agonists in spontaneous hypertension. Hypertension 1994; 24:611-9. [PMID: 7960022 DOI: 10.1161/01.hyp.24.5.611] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Abnormal central cholinergic activity has been reported to be responsible in part for the pathogenesis of high blood pressure in spontaneously hypertensive rats (SHR). Administration of cholinergic agonists in brain and spinal cord results in exaggerated pressor responses in SHR. Studies to date have focused largely on the muscarinic cholinergic system. Recently, we demonstrated that intrathecal administration of nicotinic agonists results in pressor, tachycardic, and irritation responses. In the present study we examine the cardiovascular and behavioral responses to nicotine and cytisine administered intrathecally in La Jolla strain (LJ) SHRLJ and age-matched Wistar-Kyoto (WKYLJ) rats. Nicotinic agonists produced augmented pressor, heart rate, and irritation responses in SHRLJ compared with normotensive rats. In both SHRLJ and WKYLJ rats, cytisine elicited a greater nociceptive response and greater spinobulbar component to the pressor response than nicotine. SHRLJ and WKYLJ rats also differ in that the SHRLJ strain shows a diminished tendency for desensitization to cytisine. As in Sprague-Dawley rats, in SHRLJ and WKYLJ rats the cardiovascular and behavioral responses to intrathecal nicotine were significantly inhibited by mecamylamine, dihydro-beta-erthyroidine, and methyllycaconitine. However, methyllycaconitine, which effectively blocked cytisine-elicited cardiovascular and behavioral responses in Sprague-Dawley and WKYLJ rats, was unable to inhibit the maximal rise in cystine-elicited blood pressure, heart rate, and irritation responses in SHRLJ. In contrast to the heightened cardiovascular and behavioral responses, the number of nicotinic binding sites in spinal cord membranes was significantly decreased in the hypertensive rats.(ABSTRACT TRUNCATED AT 250 WORDS)
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Khan IM, Taylor P, Yaksh TL. Cardiovascular and behavioral responses to nicotinic agents administered intrathecally. J Pharmacol Exp Ther 1994; 270:150-8. [PMID: 8035311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
We have examined the role of the spinal nicotinic receptors in mediating cardiovascular and behavioral responses in conscious rats. Intrathecal administration of nicotinic agonists to the lumbosacral region of the spinal cord caused a dose-dependent increase in systolic blood pressure, heart rate and a nociceptive (behavioral) response. The order of potencies for the pressor response was l-nicotine > or = cytisine > N-methylcarbamylcholine > or = dimethylphenylpiperazinium > d-nicotine. However, cytisine was the most potent in producing the heart rate increase and nociceptive response. Unlike the other agonists, cytisine also exhibited marked desensitization of the three responses upon repeated administration. The effects of nicotine were antagonized in a dose-dependent fashion by mecamylamine, hexamethonium, alpha-lobeline, dihydro-beta-erythroidine and methyllycaconitine. By contrast, cytisine-induced responses were blocked effectively by mecamylamine and methyllycaconitine, but not by alpha-lobeline or dihydro-beta-erythroidine. However, when alpha-lobeline or dihydro-beta-erythroidine antagonism of the pressor response to cytisine was monitored during the initial minute following intrathecal administration, both antagonists significantly inhibited the response. The competitive ganglionic blocker, trimethaphan, or the elapid alpha-toxin, alpha-bungarotoxin, when administered intrathecally, had no effect on nicotine- or cytisine-elicited responses. The cardiovascular responses to intrathecal nicotine and cytisine have two components. The first is likely mediated through direct sympathetic output and desensitizes rapidly to cytisine, the second is coupled indirectly to the nociceptive response and shows a diminished capacity for rapid desensitization. Agonist and antagonist specificities indicate that the spinal nicotinic receptor differs from those in ganglia and those characterized in brain to date. Although antagonist specificity of the blockade of nicotine and cytisine elicited responses differ, this may be due to the unique desensitization capacity of cytisine rather than an action mediated by distinct receptor subtypes.
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Khan IM, Yaksh TL, Taylor P. Ligand specificity of nicotinic acetylcholine receptors in rat spinal cord: studies with nicotine and cytisine. J Pharmacol Exp Ther 1994; 270:159-66. [PMID: 8035312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Administration of nicotinic agonists to the spinal cord leads to a variety of cardiovascular and behavioral responses. The discrete localization of afferent and efferent fibers presents a system in which occupation of nicotinic receptor subtypes might be correlated with specific pharmacologic responses. To this end, we examined [3H]cytisine and [3H]nicotine binding to membranes isolated from regions of the rat spinal cord. [3H]Cytisine showed saturable, noncooperative (nH congruent to 1) binding to a single-class of sites with a Kd of 0.44 +/- 0.01 nM and total saturable sites of 19.9 +/- 0.9 fmol/mg of protein. [3H]Cytisine binding to membranes from intermediolateral cell column and dorsal and ventral sections of the lumbosacral regions each revealed a single class of binding sites with virtually identical Kd values. However, the dorsal sections of the lumbar spinal cord contained a higher number of total binding sites than ventral lumbar or intermediolateral sections. The rank order potencies of the nicotinic agonists competing for [3H]cytisine binding was cytisine > I-nicotine > N-methylcarbamylcholine > dimethylphenylpiperazinium > acetylcholine > d-nicotine > carbamylcholine. Competitive antagonists also competed with high affinities (Ki as low as nanomolar) with the order of potencies being alpha-lobeline > or = dihydro-beta-erythroidine >> methyllycaconitine, whereas the channel blockers, mecamylamine and hexamethonium, only competed at concentrations > or = 100 microM. Competitive ganglionic blockers such as d-tubocurarine or trimethaphan and neurotoxins such as alpha-bungarotoxin, alpha-cobratoxin or neuronal bungarotoxin had weak affinities for cytisine sites. Similar to [3H]cytisine, [3H]nicotine also revealed a saturable single class of binding sites, but of lower affinity. The rank order of Ki values of the agonists, antagonists and neurotoxins for competing with [3H]nicotine binding was similar to the order for [3H]cytisine. Nicotinic receptors in the spinal cord membrane show a specificity for both agonists and antagonists that differ from neuronal receptors in the ganglia or the regions of the brain characterized to date. These findings, when correlated with the pharmacological responses documented in the comparison article suggests that the spinal nicotinic receptors may define a new member of the neuronal nicotinic receptor family.
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Khan IM, Zammit PS, Green M, Buluwela L. A simple ligation step improves the efficiency of T-overhang vectors. Trends Genet 1994; 10:225-6. [PMID: 7522367 DOI: 10.1016/0168-9525(94)90156-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Muir JD, Khan IM, Kamalati T, Buluwela L. Identification and characterisation of a novel gene expressed in human keratinocytes. Biochem Soc Trans 1994; 22:183S. [PMID: 7958248 DOI: 10.1042/bst022183s] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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Khan IM, Fisher RA, Johnson KJ, Bailey ME, Siciliano MJ, Kessling AM, Farrer M, Carritt B, Kamalati T, Buluwela L. The SON gene encodes a conserved DNA binding protein mapping to human chromosome 21. Ann Hum Genet 1994; 58:25-34. [PMID: 8031013 DOI: 10.1111/j.1469-1809.1994.tb00723.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We report the identification and characterization of a clone for the DNA binding protein SON, which we have isolated from a human keratinocyte cDNA library. Using this clone we have found that the SON gene is expressed in different cell types and that homologous sequences can be detected in vertebrate and insect genomic DNA. Using the polymerase chain reaction (PCR) to amplify SON sequences from a panel of somatic cell hybrids we have assigned the gene encoding human SON to chromosome 21. By use of hybrids containing regions of chromosome 21 the localization has been refined to 21q 22.1-q22.2.
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Khan IM, Yamaji I, Miller DH, Margolius HS, Privitera PJ. Cerebrospinal fluid kallikrein in spontaneously hypertensive and desoxycorticosterone acetate-salt hypertensive rats. J Hypertens 1993; 11:1039-45. [PMID: 8258667 DOI: 10.1097/00004872-199310000-00006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
OBJECTIVE To determine whether immunoreactive tissue kallikrein levels in cerebrospinal fluid (CSF) of spontaneously hypertensive rats (SHR) and desoxycorticosterone acetate (DOCA)--salt-treated hypertensive rats are elevated compared with normotensive Wistar-Kyoto (WKY) and Sprague-Dawley rats. DESIGN The present study was designed to test the hypothesis that the activity of the brain tissue kallikrein-kinin system is enhanced in hypertensive states. METHODS Age-matched 18- to 19-week-old SHR and WKY rats, and Sprague-Dawley rats treated for 6 weeks either with 2 mg/kg per day DOCA subcutaneously and 0.9% saline in the drinking water, or with vehicle and tap water to drink, were studied. CSF was collected from a cannula inserted into the cisterna magna, and was frozen until the tissue kallikrein in the samples was measured by radioimmunoassay. Arterial pressure in the SHR and WKY rats was measured directly via a cannula inserted in the femoral artery or by tail-cuff plethysmography. RESULTS In adult 18- to 19-week-old SHR the CSF kallikrein concentration was higher than in WKY rats. The CSF flow rate in SHR was also higher than in WKY rats. The rate of appearance of kallikrein in the CSF of SHR was twice that in WKY rats. Moreover, CSF kininogenase activity in SHR was significantly higher than that in age-matched WKY rats. In DOCA--salt hypertensive rats the CSF kallikrein concentration was higher than in vehicle-treated control rats. Acute elevation of blood pressure with a 120-min intravenous phenylephrine infusion did not change the CSF kallikrein concentration in 50 rats compared with vehicle-treated control rats. This is the first study to quantitate immunoreactive tissue kallikrein in the CSF of rats and to show elevated levels of CSF kallikrein in hypertensive rats compared with normotensive rats. CONCLUSION The present data suggest that higher brain kallikrein activity in hypertensive rats may play a role in the development of elevated blood pressure.
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Khan IM, Coulson JM. A novel method to stabilise antisense oligonucleotides against exonuclease degradation. Nucleic Acids Res 1993; 21:4433. [PMID: 8415024 PMCID: PMC310107 DOI: 10.1093/nar/21.18.4433] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
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Khan IM, Coulson JM. A novel method to stabilise antisense oligonucleotides against exonuclease degradation. Nucleic Acids Res 1993; 21:2957-8. [PMID: 8392712 PMCID: PMC309707 DOI: 10.1093/nar/21.12.2957] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
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Khan IM, Malcolm AD, Kamalati T, Buluwela L. Protein-DNA interactions and a putative papillomavirus binding factor. Biochem Soc Trans 1992; 20:212S. [PMID: 1327912 DOI: 10.1042/bst020212s] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Khan IM, Schwartz JJ, Woo D, Garcia RE. Preparation of human cord sera for enzymatic triglyceride assays: removal of free glycerol by ultrafiltration. Anal Biochem 1988; 174:496-500. [PMID: 3239752 DOI: 10.1016/0003-2697(88)90049-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Enzymatic triglyceride assays that generate glycerol from triglycerides as a part of the enzymatic process in quantitating serum triglyceride levels give elevated values when external free glycerol is present. Our objective was to develop an ultrafiltration technique that would remove exogenous and/or endogenous free glycerol from small aliquots of human cord sera so that accurate serum triglyceride values could be obtained with the commercially available triglyceride assay kits. Exogenous glycerol was completely removed from cord sera when the samples were washed twice with saline in Amicon Centricon-30 microconcentrators. This ultrafiltration technique lowered cord serum triglyceride levels significantly (P less than 0.001), but had no effect on cord total serum cholesterol levels. A comparison of washed and unwashed cord sera by either polyacrylamide or agarose gel electrophoresis indicated that the serum protein and lipoprotein profiles were not altered by the ultrafiltration process.
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Ritzhaupt LK, Nowak RA, Calvo FO, Khan IM, Bahr JM. Adenylate cyclase activity of the corpus luteum during the oestrous cycle of the pig. JOURNAL OF REPRODUCTION AND FERTILITY 1986; 78:361-6. [PMID: 3806502 DOI: 10.1530/jrf.0.0780361] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Basal adenylate cyclase values for corpora lutea (CL) removed from cyclic gilts on Days 3, 8, 13 and 18 were 178 +/- 61, 450 +/- 46, 220 +/- 25 and 208 +/- 18 pmol cAMP formed/min/mg protein, respectively. Basal activity was significantly elevated on Day 8 (P less than 0.001). LH-stimulatable adenylate cyclase values for CL from Days 3, 8, 13 and 18 were 242 +/- 83, 598 +/- 84, 261 +/- 27 and 205 +/- 17 pmol cAMP formed/min/mg protein respectively. Serum progesterone concentrations of 12 gilts bled every 2 days through one complete oestrous cycle ranged from 1.1 to 26.9 ng/ml with highest values between Days 8 and 12. The decline in serum progesterone concentrations was coincident with the decrease in basal adenylate cyclase activity. There was no LH-stimulatable adenylate cyclase activity present in the CL at the specific times of the oestrous cycle examined. We conclude that progesterone secretion by the pig CL is apparently dependent on basal activity of adenylate cyclase.
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Khan IM, Chandan RC, Shahani KM. Bovine pancreatic lipase. II. Stability and effect of activators and inhibitors. J Dairy Sci 1976; 59:840-6. [PMID: 818137 DOI: 10.3168/jds.s0022-0302(76)84285-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Purified bovine pancreatic lipase was highly unstable at and above refrigeration temperature. However, it could be stored frozen without loss of activity. Milk solids had some protective effect upon the enzyme against gamma-irradiation. Low concentrations of sodium, calcium, and magnesium salts stimulated lipolytic activity. However, heavy metal salts, such as ferric, cupric, and mercuric chlorides, were highly inhibitory. The bovine pancreatic lipase appeared to contain sulfhydryl groups which may be essential for the lipolytic activity since p-chloromercuribenzoate, N-ethylmaleimide, sodium arsenite, and iodoacetate inhibited the enzyme. A comparison of bovine pancreatic lipase and milk lipase revealed that the two enzymes were similar in thermal stability and effect of some of the activators and inhibitors on lipolytic activity.
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Chandan RC, Khan IM, Shahani KM. Bovine pancreatic lipase. III. Lipolysis of oils and fats and fatty acid specificity. J Dairy Sci 1976; 59:847-53. [PMID: 944720 DOI: 10.3168/jds.s0022-0302(76)84286-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Purified bovine pancreatic lipase hydrolyzed butteroil, vegetable oils, and synthetic glycerides. The enzyme hydrolyzed triglycerides more rapidly than di- and monoglycerides and tripropionin faster than any other synthetic glyceride. Triacetin was the least hydrolyzed glyceride. Gas-liquid chromatographic analysis of the free fatty acids liberated by the lipase from milk fat indicated that the enzyme selectively liberated butyric acid in higher proportion than the relative amount originally in the fat. The enzyme released saturated as well as unsaturated fatty acids from commericial vegetable oils. With regard to the lipolytic behavior, in general, the bovine pancreatic lipase closely resembled milk lipase.
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Shahani KM, Khan IM, Chandan RC. Bovine pancreatic lipase.I.Isolation, homogeneity, and characterization. J Dairy Sci 1976; 59:369-75. [PMID: 4478 DOI: 10.3168/jds.s0022-0302(76)84214-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Bovine pancreatic lipase was isolated in pure form by lyophilization of fresh bovine pancreas, extraction of the enzyme with sucrose solution, fractional precipitation with ammonium sulfate and acetone, followed by chromatography on Sephadex G-100. The specific activity of the purest lipase fraction was 1750 micromoles fatty acid, liberated in 30 min per milligram of protein, indicating a purification of approximately 473-fold, with an overall yield of about 42%. Homogeneity of the enzyme was confirmed by rechromatography on Sephadex G-100 as well as with the gel electrophoretic and ultracentrifugal techniques. The purified enzyme gave a typical protein ultraviolet absorption spectrum with maximum absorption at 276 nm and minimum at 252 nm. The purified enzyme exhibited a single pH optimum of 8.8 and an isoelectric point near pH 5.5. Its optimum temperature was 37 C, and its optimum substrate concentration was 10%. These properties resembled those of milk lipase.
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74
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Das BC, Khan IM, Rahman A. Textiloma: a case of foreign body mimicking a dermoid/mesenteric cyst. Pulse (Basel) 1970. [DOI: 10.3329/pulse.v3i1.6548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Items such as cotton or gauze pads can be mistakenly left behind during operations. Such foreign materials (called textiloma) cause foreign body reaction in the surrounding tissue. The complications caused by these foreign bodies are well known, but cases are rarely published because of medico-legal implications. Some textilomas cause infection or abscess formation in the early stage, whereas others remain clinically silent for many years. Here, we describe a case of textiloma in which the patient presented with huge abdominal lump 6 years after caesarean section operation abroad. Imaging revealed a dermoid / mesenteric cyst in pelvis and left lower abdomen. The case was treated successfully in Apollo Hospitals Dhaka and discussed here in the light of published literature.DOI: 10.3329/pulse.v3i1.6548Pulse Vol.3(1) July 2009 p20-22
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Das BC, Khan IM, Alam Q, Rahman A. Carcinoma transvers colon with caecal perforation mimicking appendicular lump. Pulse (Basel) 1970. [DOI: 10.3329/pulse.v3i1.6552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
A 43 year-old female with caecal perforation and localized peritonitis as a result of transverse colon malignant stricture was presented. Initially she was evaluated in two different clinics and treated conservatively as appendicular lump. She was brought to Apollo Hospitals Dhaka as her condition deteriorated. CECT abdomen disclosed an annular soft tissue mass at mid part of transverse colon that completely obstructed the lumen. The colon proximal to the lesion and small bowel were grossly dilated and filled up with fecal matter. On laparotomy, a lump was noted in right iliac fossa which was made of omentum, small bowel and lateral abdominal wall. A perforation was noted in the lateral wall of caecum after dismantling the lump. The colon and the small bowel were decompressed through caecal perforation site peroperatively. Right hemicolectomy and primary anastomosis was performed. Patient survived the operation and she was discharged from hospital on the 10th postoperative day with an advice of regular follow up in surgical OPD. She was referred to Oncology centre for chemotherapy.In conclusion, any patient around the age of forty or above with features of appendicular lump deserves full work-up including CECT to exclude colonic malignancy. Resection and primary anastomosis may be a preferred procedure for right colonic carcinoma perforation.DOI: 10.3329/pulse.v3i1.6552Pulse Vol.3(1) July 2009 p29-30
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Khan IM, Dill CW, Chandan RC, Shahani KM. Production and properties of the extracellular lipase of Achromobacter lipolyticum. BIOCHIMICA ET BIOPHYSICA ACTA 1967; 132:68-77. [PMID: 6030360 DOI: 10.1016/0005-2744(67)90192-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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