Biomedical subjects

J Iqbal

Publications and source records attributed to J Iqbal.

At least 37 records · Page 2Linked to original sources

PubMed2003

Suppression of 7,12-dimethylbenz[alpha]anthracene-induced carcinogenesis and hypercholesterolaemia in rats by tocotrienol-rich fraction isolated from rice bran oil.

The anti-tumour and anti-cholesterol impacts of tocotrienol-rich fraction (TRF) were investigated in rats treated with the chemical carcinogen 7,12-dimethylbenz [alpha]anthracene (DMBA), which is known to induce mammary carcinogenesis and hypercholesterolaemia. DMBA administration to rats was associated with the appearance of multiple tumours on mammary glands after 6 months. Alkaline phosphatase (ALP) and glutathione-S-transferase (GST) are used as marker enzymes to monitor the severity of carcinogenesis. Although no tumours were visible on livers, hepatic ALP and GST activities of DMBA-treated rats were profoundly elevated in comparison to enzyme activities of normal control rats. Feeding of TRF (10 mg/kg body weight/day) for 6 months, isolated from rice bran oil (RBO), to DMBA-administered rats, reduced the severity and extent of neoplastic transformation in the mammary glands. Similarly, plasma and mammary ALP activities increased during carcinogenesis (95% and 43%, respectively), were significantly decreased in TRF-treated rats, whereas TRF mediated a further increase of 51% in hepatic ALP activity. TRF treatment to rats maintained low levels of GST activities in liver ( approximately 32%) and mammary glands ( approximately 21%), which is consistent with anti-carcinogenic properties of TRF. Administration of DMBA also caused a significant increase of 30% in plasma total cholesterol and 111% in LDL-cholesterol levels compared with normal control levels. Feeding of TRF to rats caused a significant decline of 30% in total cholesterol and 67% in LDL-cholesterol levels compared with the DMBA-administered rats. The experimental hypercholesterolaemia caused a significant increase in enzymatic activity (23%) and protein mass (28%) of hepatic 3-hydroxy-3-methylglutaryl co-enzyme A (HMG-CoA) reductase. Consistent with TRF-mediated reduction in plasma lipid levels, enzymatic activity and protein mass of HMG-CoA reductase was significantly reduced. These results indicate that TRF has potent anti-cancer and anti-cholesterol effects in rats.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed2003

Serum protein electrophoretic pattern in young and adult camels.

OBJECTIVE: To compare the electrophoretic pattern of serum proteins in clinically healthy adult camels (between 3 and 8 years of age) and camel calves (less than 3 months of age). DESIGN: Laboratory analysis of serum from healthy camels. PROCEDURE: Blood was collected from 30 healthy adult camels and 30 camel calves and the serum separated. Total protein of each serum sample was estimated by automated chemistry analyser. The proteins were fractionated by automated electrophoresis on agarose gel. RESULTS: Serum proteins migrated on the agarose gel as one albumin, two alpha (alpha1 and alpha2-globulins), two beta (beta1 and beta2-globulins) and one gamma-globulin fractions. In adult camels the mean concentration of total protein, albumin alpha1, alpha2, beta1, beta2 and gamma-globulins was 56.8 +/- 1.5, 30.7 +/- 0.8, 2.4 +/- 0.1, 3.2 +/- 0.1, 9.7 +/- 0.3, 3.4 +/- 0.2 and 8.6 +/- 0.3 g/L, respectively. These values in calves were 49.7 +/- 1.8, 23.7 +/- 0.8, 3.2 +/- 0.2, 3.1 +/- 0.2, 14.2 +/- 0.2, 4.0 +/- 0.2 and 4.1 +/- 0.2 g/L, respectively. CONCLUSION: The concentration of total proteins, albumin and gamma-globulins was higher (P < 0.05) in the adult camels than in camel calves. The concentrations of beta1 globulins was higher (P < 0.05) in calves as compared to adult camels.

Aging↗

PubMed2002

Inducive effect of cresoquinone on microbiological transformation of L-tyrosine to 3,4 dihydroxy phenyl L-alanine by Aspergillus oryzae NG-11(P1).

The present work describes the inducive effect of cresoquinone on microbiological transformation of L-tyrosine to 3,4 dihydroxy phenyl L-alanine ( L-DOPA) by Aspergillus oryzae NG-11(P1). Mould mycelium was used for biochemical conversion of L-tyrosine to L-DOPA because tyrosinases, beta-carboxylases and tyrosine hydroxylases are intracellular enzymes. The maximum conversion of L-tyrosine to L-DOPA (0.428 mg/ml) was achieved after 60 min of biochemical reaction. To enhance the production of L-DOPA, cresoquinone was added to the reaction mixture. Best L-DOPA biosynthesis results were observed when the concentration of cresoquinone was 3.5 x 10(-6) M (1.686 mg/ml L-DOPA produced with 1.525 mg/ml consumption of L-tyrosine). Cresoquinone not only increased enzyme activity but also enhanced cell membrane permeability to facilitate secretion of enzymes into the reaction broth. Comparison of kinetic parameters revealed the ability of the mutant to yield L-DOPA [Y(p/x) [i.e., mg L-DOPA formed (mg cells formed)(-1)] =7.360+/-0.04]. When the culture grown on various cresoquinone levels was monitored for Q(p), Q(s) and q(p) [ Q(p): mg L-DOPA produced ml(-1) x h(-1); Q(s): mg substrate consumed ml(-1) x h(-1); q(p): mg L-DOPA formed (mg cells)(-1) h(-1)], there was significant enhancement ( P<0.025) of these variables.

Aspergillus oryzae↗

PubMed2002

Influence of cultivation conditions on citrate production by Aspergillus niger in a semi-pilot-scale plant.

The influence of some fermentation parameters on the semi-pilot scale (alteration of growth conditions, e.g., sugar concentration, incubation temperature and initial pH) on citrate production was demonstrated in parent and mutant strains of Aspergillus niger. Raw material from sugar industry (cane molasses) was examined as basal fermentation medium in a stirred stainless-steel 15-L fermentor. After growth on medium with 150 g/L sugar, the parent strain produced 51.2 g/L citric acid; the mutant strain achieved production maximum of 96.2 g/L. Comparing the growth, kinetic (volumetric substrate uptake rate, rate of substrate consumption and volumetric productivity rate) and production parameters it was found that the mutant strain grows more rapidly, with slightly changed morphology (intermediate, shiny round pellets with diameter 0.6-0.7 mm), and exhibits a higher citrate production and higher efficiency of sugar utilization.

Aspergillus niger↗

PubMed2002

Serotonin-Cu(II)-mediated DNA cleavage: mechanism of copper binding by serotonin.

It has been proposed that considerable DNA damage may be caused by endogenous metabolites produced during the body's normal metabolic processes. 5-hydroxytryptamine (serotonin) is an important neurotransmitter in brain and spinal cord. We have previously shown that serotonin induces oxidative cleavage of DNA strands in the presence of copper ions. In the present paper we have examined the mechanism of copper binding by serotonin using absorption spectroscopy, Cu(II)-mediated lipid peroxidation and by determining the oxidation of the serotonin molecule. Addition of increasing concentrations of Cu(II) to serotonin leads to a progressive enhancement in the absorption band and is accompanied by a shift towards a lower wavelength indicative of the formation of an oxidised species of serotonin. Studies with the structurally related molecules tryptophan and melatonin showed that only serotonin is able to reduce Cu(II) to Cu(I). Similarly, only serotonin was found to be able to abolish the copper-mediated peroxidation of mitochondria. These results suggested the involvement of the phenolic group in copper binding. Further, it was also shown that the binding of copper to serotonin leads to the formation of a quinone in the absence of molecular oxygen. Based on these results, a model has been proposed in which serotonin reduces two molar equivalents of Cu(II) to Cu(I) through a reaction involving two electron oxidation of the phenolic ring to a quinone methide.

Animals↗

PubMed2002

Equid herpesvirus 1 is neurotropic in mice, but latency from which infectious virus can be reactivated does not occur.

Equid herpesvirus 1 (EHV-1) is the most common cause of virus-induced abortion in horses. After primary infection the virus becomes latent predominantly in the respiratory tract lymph nodes and the genome can also be detected in the peripheral nervous system. The role of mouse as a feasible model for the establishment of latency and reactivation of EHV-1 was investigated. Intracerebral and intranasal infections of 3- and 17-day-old mice were made and virus replication was confirmed by virus isolation and detected by indirect immunofluorescence (IIF) in brain. For reactivation studies, the mice were killed 8 weeks post infection and tissues were collected for cocultivation. In mice from both age groups, infectious virus was not detected by cocultivation. Following attempts to reactivate virus in vivo with corticosteroids, the viral antigen was detected at low levels by IIF and the expression of the gB gene by reverse transcription polymerase chain reaction (RT-PCR) in brain, trigeminal ganglia, olfactory lobe, lung and spleen. Virus was also detected by IIF following incubation of tissue explants in the growth medium containing pokeweed mitogen (PWM). These results show the limitations of the mouse model for investigating EHV-1 latency and highlights the issue of 'ineffective reactivation' of virus.

Abortion, Veterinary↗

PubMed2001

Immunohistochemical characterization of localization of long-form leptin receptor (OB-Rb) in neurochemically defined cells in the ovine hypothalamus.

Leptin, a hormone secreted from the adipose tissue, is involved in the regulation of food intake and neuroendocrine function, by modulation of the expression and/or function of various neuropeptides in the hypothalamus. The long isoform (OB-Rb) is the major signaling form of the leptin receptor in the hypothalamus. We have used double-labeling immunohistochemistry to examine the extent of OB-Rb expression in neurochemically defined cell types in the ovine hypothalamus. OB-Rb-like immunoreactivity was widespread within cells localized to the periventricular, paraventricular, supraoptic, dorsomedial hypothalamic, ventromedial hypothalamic and arcuate nuclei, as well as the median eminence, perifornical, anterior hypothalamic and lateral hypothalamic areas and the zona incerta. Double-labeling showed expression of OB-Rb in 59.6+/-6.0% neuropeptide Y-containing cells, 60.8+/-4.7% galanin-containing cells, 89.8+/-2.65% pro-opiomelanocortin-containing cells, 73.4+/-3.5% tyrosine hydroxylase-containing cells and 31.8+/-2.8% corticotropin-releasing factor-containing cells. Interestingly 100% of melanin-concentrating hormone and orexin positive cells were also OB-Rb immunoreactive. These data provide semi-quantitative information on the extent to which various cell types express OB-Rb in the hypothalamus. Expression of OB-Rb within specific neuropeptidergic neurons provides evidence for the direct action of leptin upon the various neurochemical systems that regulate food intake, neuroendocrine and autonomic function in the brain.

Animals↗

PubMed2001

Long-term alterations in body weight do not affect the expression of melanocortin receptor-3 and -4 mRNA in the ovine hypothalamus.

The pro-opiomelanocortin-derived peptides and the melanocortin receptors are implicated in various functions within the CNS including the regulation of food intake. In the present study, we used in situ hybridization, with specific 35S-labelled ovine riboprobes to map the expression of melanocortin receptor-3 (MC3-R) and -4 (MC4-R) mRNA in the diencephalon and brainstem of normal female sheep. Furthermore, we examined the effect of long-term alterations in energy balance on the distribution and expression of MC3-R and MC4-R mRNA in food-restricted and ad libitum-fed ovariectomized female sheep. The distribution of melanocortin receptors generally resembled that of the rat. A high number of MC3-R-labelled cells were seen in the ventral division of the lateral septum and the medial preoptic area. In the hypothalamus, a moderate number of MC3-R-labelled cells was observed in the lateral hypothalamic area while other nuclear groups had low to intermediate numbers of MC3-R-labelled cells. The distribution of MC4-R mRNA was generally similar to that of MC3-R mRNA in the septal/preoptic and hypothalamic regions, with a high number of labelled cells present in the intermediate division of the lateral septum. Within the hypothalamus, no MC4-R mRNA expression was observed in the arcuate nucleus. There was more widespread distribution of moderate to low numbers of MC4-R mRNA-expressing cells in the brainstem compared to that of MC3-R mRNA. Unlike findings in the rat, only a low number of cells expressed melanocortin receptor mRNA in the ovine hypothalamic nuclei associated with feeding behavior. The number of melanocortin receptor-labelled cells and the level of expression (silver grains/cell) in the hypothalamic feeding centers was similar in food-restricted and ad libitum-fed animals. These findings suggest that long-term alterations in metabolic status do not change the melanocortin receptor mRNA distribution and/or expression in the sheep hypothalamus.

Animals↗

PubMed2001

Studies on the inactivation of soluble and immobilized papain by the ascorbic acid-Cu2+ system: a model to propose the effect of free radicals on membrane-bound enzymes in vivo.

Free radicals have been suggested to be widely implicated as the species responsible for harmful biological processes, such as aging, carcinogenesis and numerous other diseases. The mechanism of biological damage produced in such processes has been investigated in a wide variety of systems, including studies on proteins, enzymes, nucleic acids and carbohydrates. In the present study we selected an ascorbic acid-transition-metal ion (ASA-Cu(2+)) system in order to understand the mechanism of soluble and membrane-bound enzyme inactivation by generating free radicals. Papain, a thiol protease, was immobilized on an immobilized-metal-ion carrier and used as a model to examine the inactivation behaviour of membrane-bound enzymes. A comparison was made between the inactivation of soluble and immobilized papain by free radicals, and the potential of different radical scavengers to prevent the inactivation of enzyme was examined.

Ascorbic Acid↗

PubMed2001

Cryptosporidiosis in Kuwaiti children: seasonality and endemicity.

OBJECTIVE: To detect the incidence of cryptosporidial infection in children presenting with gastrointestinal symptoms at the local hospital in Kuwait. METHODS: Over a period of 3 years, September 1995 to August 1997, a single fecal sample from 3549 children was analyzed by modified saframin-methylene blue (SM-B) staining and a direct immunofluorescence test for the presence of Cryptosporidium oocysts. RESULTS: Cryptosporidium oocysts were detected in 51 (10%) children with diarrhea. Prevalence was highest (73%) in children > 2 years of age compared with children < 2 years of age. The maximum number of cases, 38 of 51 (75%), was seen during the months January to April, indicating a marked seasonal variation. Polyparasitism was common in children with diarrhea; however, 43 of the 51 (84%) children with cryptosporidiosis had cryptosporidium infection only. Blastocystis hominis and Endolimax nana were the most common parasites detected (38% and 15%, respectively). Forty-seven of the 51 (90%) children with cryptosporidiosis were Kuwaiti and gave no history of travel abroad, suggesting that the infection was acquired indigenously. Sociodemographic information on children with cryptosporidiosis suggests three possible modes of transmission of infection: drinking contaminated water stored in overhead water tanks, person to person, or contact with infected animals. CONCLUSION: In this study, we observed water-borne transmission of cryptosporidium infection in children with diarrhea. The infection is seasonal and endemic.

Age Factors↗

PubMed2001

Evidence that orexin-containing neurones provide direct input to gonadotropin-releasing hormone neurones in the ovine hypothalamus.

Orexins A and B (ORX) have been added recently to the growing list of neuropeptides implicated in feeding and drinking behaviour as well as neuroendocrine function. In the present study, we have used single and dual labelling immunohistochemistry and a rabbit polyclonal anti-orexin-A antibody, which recognizes both ORX A and B, to examine ORX pathways in the sheep hypothalamus. ORX immunoreactive cells were distributed in the dorsomedial hypothalamic nucleus, lateral hypothalamic area, zona incerta and perifornical area; a few cells were also observed in the anterior hypothalamic area. In contrast to distribution in the rat brain, most of the ORX immunoreactive cells are localized to the dorsomedial hypothalamic nucleus and perifornical area; scattered cells are found in lateral hypothalamic area. ORX immunoreactive fibres were widely distributed throughout the hypothalamus and preoptic area with dense innervation of the medial preoptic area and bed nucleus of stria terminalis. Dual labelling demonstrated widespread expression of the long form of the leptin receptor within all ORX cells that were examined. Thirty percent of the gonadotropin releasing hormone (GnRH) cells that were examined had ORX immunoreactive terminals in close contact with no regional or sex differences. FluoroGold injections into the preoptic area retrogradely labelled a subpopulation of ORX cells in the lateral hypothalamic/perifornical area, showing ORX cells of this region project to the preoptic and could potentially provide input to GnRH cells. These findings suggest an integral role for ORX in the regulation of GnRH cells in the sheep and thus provide evidence of a novel mechanism whereby leptin can influence reproductive neuroendocrine function.

Afferent Pathways↗

PubMed2001

EHV-1 gene63 is not essential for in vivo replication in horses and mice, nor does it affect reactivation in the horse: short communication.

The aim of this study was to investigate the role of immediate early gene (gene63) in the pathogenesis of equine herpesvirus 1 (EHV-1) acute and latent infections in equine and murine models. EHV-1 gene63 mutant virus (g63mut) along with EHV-1 (Ab4) was used for intracerebral and intranasal infection of 3 and 17-day-old mice. Both viruses were recovered at the same frequency from tissues after infection. Two Welsh ponies were infected via the intranasal route with each of the viruses. Acute infection was monitored by virus isolation from nasal swabs and peripheral blood leukocytes. Six weeks post infection, peripheral blood leukocytes were taken from ponies and in vitro reactivation was positive for both viruses. At autopsy, both viruses were isolated by co-cultivation from bronchial and submandibular lymph nodes. These findings indicate that the mutation of EHV-1 gene63 does not play a role in the establishment and reactivation from latency.

Acute Disease↗

PubMed2001

Invasive amebiasis: challenges in diagnosis in a non-endemic country (Kuwait).

Invasive zymodemes of the enteric protozoan Entamoeba histolytica infect the large intestine and cause extra-intestinal lesions such as amebic liver abscess (ALA). The clinical manifestations of ALA are protean, particularly in patients presenting in a non-endemic, desert country such as Kuwait, and diagnosis becomes problematic. In this study, we present cases of ALA to illustrate the clinical and diagnostic challenges. For serodiagnosis of ALA, we compared the sensitivity and specificity of the indirect hemagglutination assay (IHA) with the ImmunoTab assay and an enzyme-linked immunosorbent assay (ELISA) for this geographic region. We tested sera of 110 patients with ALA, 1,224 patients suspected of having invasive amebic infection, and 50 Europeans with no travel history to an amebic-endemic area. The IHA was simple, rapid, easy to perform, and reliable (sensitivity = 99%, specificity > 95%). The performance of the IHA in detecting ALA in suspected cases was significantly better than that of the ELISA and the ImmunoTab test. Compared with the IHA, both the ELISA and ImmunoTab assay detected relatively higher numbers of false-positive cases (4.7% and 3.6%, respectively). With the availability of ultrasound and computed tomography scans, the serology correlates excellently with the clinical presentation. In chronic cases where fibrosis may be present around the abscess, the IHA has limitations, as in the follow-up of treated patients. Pitfalls in diagnosis are highlighted by discussing the differential diagnosis of ALA from bacterial hepatic abscesses and infected hydatid cysts. Most importantly, the IHA in such cases was invariably at a titer that is considered not significant.

Adult↗

PubMed2000

Localization of long-form leptin receptor in the somatostatin-containing neurons in the sheep hypothalamus.

Reduction in the adiposity or dietary restriction increases plasma growth hormone (GH) concentrations, and in sheep this appears to be due, at least in part, to a reduction in the concentrations of somatostatin (SRIF) in hypophyseal portal blood. Leptin is a hormone secreted by the adipocytes and it is possible that the effects of altered adiposity or fasting on GH secretion could be due to regulation of SRIF neurons by leptin. To ascertain the extent to which leptin may act on these neurons, we have used immunohistochemistry to examine co-localization of long-form of the leptin receptor (OB-Rb) and SRIF in the sheep hypothalamus. In the hypothalamic periventricular area (PeriV), 44.5+/-10% of SRIF cells were found to co-stain for OB-Rb. In the dorsomedial hypothalamic, ventromedial hypothalamic and arcuate nuclei, 100% of SRIF immunoreactive neurons expressed OB-Rb. These findings provide a basis for the direct action of leptin on SRIF neurons. Thus, it is possible that leptin stimulates the secretion of SRIF in relatively obese individuals. The significance of the lower number of SRIF cells in the PeriV co-localizing OB-Rb expression is not clear at present.

Animals↗

PubMed2000

Incidence, biochemical and haematological alterations induced by natural trypanosomosis in racing dromedary camels.

In this study 10.67% incidence of trypanosomosis was observed in 150 racing camels by Suratex (latex agglutination). A significant decrease (P<0.05) in RBC, Hb, PCV and lymphocyte was observed, while a significant (P<0.05) increase in WBC and neutrophils was noted in trypanosomosis positive samples. The blood chemistry parameters indicated that there was significant (P<0.05) decrease in iron and albumin, but no significant alteration was observed in alkaline phosphatase (ALP), alanine aminotransferase (ALT), asparate aminotransferase (AST), gamma glutamyltransferase (GGT), lactic dehydrogenase (LDH), urea, total protein, calcium, creatinine, phosphorous and magnesium.

Animals↗

PubMed2000

Age-related effects of TGF-beta on proteoglycan synthesis in equine articular cartilage.

The synthesis of proteoglycans was measured in normal equine articular cartilage of ages 9 months to 20 years and the effect of TGF-beta1 on this activity was investigated. The rate of incorporation of [(35)S]Na(2)SO(4) decreased with age as did the responsiveness of the tissue to the growth factor. The enhanced synthesis of proteoglycan induced at all ages by TGF-beta1 was down-regulated by IL-1 beta and retinoic acid. The expression of mRNA for TGF-beta1, 2, and 3 was also measured, and although the level of TGF-beta1 was highest at all ages, the expression of each growth factor decreased with age.

Age Factors↗

PubMed2000

Intra-articular clonidine vs. morphine for post-operative analgesia following arthroscopic knee surgery (a comparative evaluation).

In a prospective, double-blind, randomised study, 30 ASA I patients were allocated to three groups in an attempt to find out the best post-operative analgesic following arthroscopic knee surgery under epidural anaesthesia. Group I patients received 5 mg of preservative-free morphine in 20 ml of normal saline, group II patients received 150 µg of clonidine in 20 ml of normal saline and group III patients received 20 ml of normal saline only. The post-operative pain was evaluated by a visual analogue scale and the need for rescue analgesic was assessed post-operatively for 12 h. We conclude that intra-articular administration of 150 µg of clonidine gives a longer lasting pain relief post-operatively (4-12 h) as compared to 5 mg of preservative-free morphine (3 h). No side effects were noted with either of the drugs.

Journal Article↗

PubMed2000

Polyclonal-antibody-mediated insolubilization and stabilization of papain.

Antisera raised in rabbits against native iodoacetamide- and iodoacetic acid-modified papain contained precipitating and non-inhibitory antibodies. Papain could be insolubilized as enzyme-antibody adducts with the gamma-globulin fraction derived from the antiserum. Two insolubilized papain preparations, designated A and B, with low and high antibody/enzyme ratios, respectively, exhibited high enzyme activity and markedly enhanced thermal and denaturant stabilities. However, papain antibody adduct B was superior in activity and stability over preparation A. The usefulness of immobilized papain in biopharmaceutical and other industries is also discussed.

Animals↗