Vitamin E, oxidative stress, and inflammation

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in the Western world. Its incidence has also been increasing lately in developing countries. Several lines of evidence support a role for oxidative stress and inflammation in atherogenesis. Oxidation of lipoproteins is a hallmark in atherosclerosis. Oxidized low-density lipoprotein induces inflammation as it induces adhesion and influx of monocytes and influences cytokine release by monocytes. A number of proinflammatory cytokines such as interleukin-1beta (IL-1beta), IL-6, and tumor necrosis factor-alpha (TNF-alpha) modulate monocyte adhesion to endothelium. C-reactive protein (CRP), a prototypic marker of inflammation, is a risk marker for CVD and it could contribute to atherosclerosis. Hence, dietary micronutrients having anti-inflammatory and antioxidant properties may have a potential beneficial effect with regard to cardiovascular disease. Vitamin E is a potent antioxidant with anti-inflammatory properties. Several lines of evidence suggest that among different forms of vitamin E, alpha-tocopherol (AT) has potential beneficial effects with regard to cardiovascular disease. AT supplementation in human subjects and animal models has been shown to decrease lipid peroxidation, superoxide (O2-) production by impairing the assembly of nicotinamide adenine dinucleotide phosphate (reduced form) oxidase as well as by decreasing the expression of scavenger receptors (SR-A and CD36), particularly important in the formation of foam cells. AT therapy, especially at high doses, has been shown to decrease the release of proinflammatory cytokines, the chemokine IL-8 and plasminogen activator inhibitor-1 (PAI-1) levels as well as decrease adhesion of monocytes to endothelium. In addition, AT has been shown to decrease CRP levels, in patients with CVD and in those with risk factors for CVD. The mechanisms that account for nonantioxidant effects of AT include the inhibition of protein kinase C, 5-lipoxygenase, tyrosine-kinase as well as cyclooxygenase-2. Based on its antioxidant and anti-inflammatory activities, AT (at the appropriate dose and form) could have beneficial effects on cardiovascular disease in a high-risk population.

(S)-13-[(dimethylamino)methyl]-10,11,14,15-tetrahydro-4,9:16, 21-dimetheno-1H, 13H-dibenzo[e,k]pyrrolo[3,4-h][1,4,13]oxadiazacyclohexadecene-1,3(2H)-d ione (LY333531) and related analogues: isozyme selective inhibitors of protein kinase C beta

Protein kinase C (PKC) is a family of closely related serine and threonine kinases. Overactivation of some PKC isozymes has been postulated to occur in several diseases states, including diabetic complications. Selective inhibition of overactivated PKC isozymes may offer a unique therapeutic approach to disease states such as diabetic retinopathy. A novel series of 14-membered macrocycles containing a N-N'-bridged bisindolylmaleimide moiety is described. A panel of eight cloned human PKC isozymes (alpha, beta I, beta II, gamma, delta, epsilon, sigma, eta) was used to identify the series and optimize the structure and associated activity relationship. The dimethylamine analogue LY333531 (1), (S)-13-[(dimethylamino)methyl]-10,11,14,15-tetrahydro-4,9:16, 21-dimetheno-1H, 13H-dibenzo[e,k]pyrrolo[3,4-h][1,4,13]oxadiazacyclohexadecene++ +-1,3(2H)-dione, inhibits the PKC beta I (IC50 = 4.7 nM) and PKC beta II (IC50 = 5.9 nM) isozymes and was 76- and 61-fold selective for inhibition of PKC beta I and PKC beta II in comparison to PKC alpha, respectively. The additional analogues described in the series are also selective inhibitors of PKC beta. LY333531 (1) exhibits ATP dependent competitive inhibition of PKC beta I and is selective for PKC in comparison to other ATP dependent kinases (protein kinase A, calcium calmodulin, caesin kinase, src tyrosine kinase). The cellular activity of the series was assessed using bovine retinal capillary endothelial cells. Retinal endothelial cell dysfunction has been implicated in the development of diabetic retinopathy. Plasminogen activator activity stimulated by a phorbol ester (4 beta-phorbol 12,13-dibutyrate) in endothelial cells was inhibited by the compounds in the series with ED50 values ranging from 7.5 to 0.21 microM. A comparison of the PKC isozyme and related ATP dependent kinase inhibition profiles is provided for the series and compared to the profile for staurosporine, a nonselective PKC inhibitor. The cellular activity of the series is compared with that of the kinase inhibitor staurosporine.

Evaluation of a single preoperative dose of pregabalin for attenuation of postoperative pain after laparoscopic cholecystectomy

BACKGROUND

Postoperative pain is the dominating complaint and the primary reason for prolonged convalescence after laparoscopic cholecystectomy. We have evaluated the efficacy of a single preoperative dose of pregabalin for attenuating postoperative pain and fentanyl consumption after laparoscopic cholecystectomy.

METHODS

Sixty adults (16-60 yr), ASA physical status I and II, of either sex undergoing elective laparoscopic cholecystectomy were included in this prospective, randomized placebo controlled, double-blind study. Subjects were divided into two groups of 30 each to receive either a matching placebo or pregabalin 150 mg, administered orally 1 h before surgery. Postoperative pain (static and dynamic) was assessed by a 100 mm visual analogue scale, where 0, no pain; 100, worst imaginable pain. Subjects received patient-controlled i.v. fentanyl analgesia during the postoperative period. Results were analysed by Student's t-test, chi(2) test, Mann-Whitney U-test, and Fisher's exact test.

RESULTS

Postoperative pain (static and dynamic) and postoperative patient-controlled fentanyl consumption were reduced in the pregabalin group compared with the placebo group (P<0.05). Side-effects were similar in both groups.

CONCLUSIONS

A single preoperative oral dose of pregabalin 150 mg is an effective method for reducing postoperative pain and fentanyl consumption in patients undergoing laparoscopic cholecystectomy.

Infectious etiologies of rhabdomyolysis: three case reports and review

Rhabdomyolysis can be precipitated by trauma, ischemia, metabolic defects, electrolyte abnormalities, drugs, and a wide variety of infectious diseases. At our institution, recent cases of rhabdomyolysis induced by influenza prompted us to review the infectious etiologies of this entity. In addition, a thorough literature search revealed numerous case reports but no general review on this subject. This study describes representative recent cases from our institution and details the wide variety of infections that can cause muscle damage. The pathophysiological mechanisms, muscle histology, and correlation with renal dysfunction are also discussed.

Structure and content of the Entamoeba histolytica genome

The intestinal parasite Entamoeba histolytica is one of the first protists for which a draft genome sequence has been published. Although the genome is still incomplete, it is unlikely that many genes are missing from the list of those already identified. In this chapter we summarise the features of the genome as they are currently understood and provide previously unpublished analyses of many of the genes.

CaCo-2 cells treated with Clostridium perfringens enterotoxin form multiple large complex species, one of which contains the tight junction protein occludin

The previous model for the action of Clostridium perfringens enterotoxin (CPE) proposed that (i) CPE binds to host cell receptor(s), forming a small ( approximately 90 kDa) complex, (ii) the small complex interacts with other eucaryotic protein(s), forming a large ( approximately 160 kDa) complex, and (iii) the large complex triggers massive permeability changes, thereby inducing enterocyte death. In the current study, Western immunoblot analysis demonstrated that CPE bound to CaCo-2 human intestinal cells at 37 degrees C forms multiple large complex species, with apparent sizes of approximately 200, approximately 155, and approximately 135 kDa. These immunoblot experiments also revealed that occludin, an approximately 65-kDa tight junction protein, is present in the approximately 200-kDa large complex but absent from the other large complex species. Immunoprecipitation studies confirmed that occludin physically associates with CPE in large complex material and also indicated that occludin is absent from small complex. These results strongly suggest that occludin becomes associated with CPE during formation of the approximately 200-kDa large complex. A postbinding association between CPE and occludin is consistent with the failure of rat fibroblast transfectants expressing occludin to bind CPE in the current study. Those occludin transfectants were also insensitive to CPE, strongly suggesting that occludin expression is not sufficient to confer CPE sensitivity. However, the occludin-containing, approximately 200-kDa large complex may contribute to CPE-induced cytotoxicity, because nontoxic CPE point mutants did not form any large complex species. By showing that large complex material is comprised of several species (one containing occludin), the current studies indicate that CPE action is more complicated than previously appreciated and also provide additional evidence for CPE interactions with tight junction proteins, which could be important for CPE-induced pathophysiology.

Clara cell 10 kDa protein (CC10): comparison of structure and function to uteroglobin

The cellular localization, functional activities and structures of rat and human Clara cell 10 kDa proteins (CC10) are compared to rabbit uteroglobin. CC10 is present exclusively in the non-ciliated cells of the surface epithelium of the pulmonary airways, whereas uteroglobin is reported to be present in the lung and reproductive organs. There is about 55% identity between the amino acid sequences of rat CC10 and either rabbit uteroglobin or human CC10. The latter two have 61% identity. Using the known structure of uteroglobin as the model, correlations between the structure and function for this group of proteins are made. Substitution of the residues for the rat and human CC10 into the structure of uteroglobin suggests that these proteins may be members of a structurally homologous family. Some of the functional differences may be due to distortion of the hydrophobic pocket in the dimeric protein and a surface hypervariability located on one contiguous helix and beta turn. Rat CC10 and rabbit uteroglobin both, nearly equally, inhibit papain and bind progesterone. Human CC10 does not inhibit papain and has markedly lower progesterone binding (4.6% of rabbit uteroglobin). Antiinflammatory activity of synthetic peptides corresponding to a homologous sequence region of uteroglobin and the two Clara cell proteins was tested. The region chosen has sequence similarity to lipocortin I. The peptides not only failed to inhibit carrageenan-induced foot pad swelling but exacerbated it. All three proteins inhibit pancreatic phospholipase A2. The phospholipase A2 inhibitory effect of CC10 may be important in regulating the inflammatory responses in the lung.

Human C-reactive protein promotes oxidized low density lipoprotein uptake and matrix metalloproteinase-9 release in Wistar rats

C-reactive protein (CRP) is present in the atherosclerotic plaques and appears to promote atherogenesis. Intraplaque CRP colocalizes with oxidized low density lipoprotein (OxLDL) and macrophages in human atherosclerotic lesions. Matrix metalloproteinase-9 (MMP-9) has been implicated in plaque rupture. CRP promotes OxLDL uptake and MMP induction in vitro; however, these have not been investigated in vivo. We examined the effect of CRP on OxLDL uptake and MMP-9 production in vivo in Wistar rats. CRP significantly increased OxLDL uptake in the peritoneal and sterile pouch macrophages compared with human serum albumin (huSA). CRP also significantly increased intracellular cholesteryl ester accumulation compared with huSA. The increased uptake of OxLDL by CRP was inhibited by pretreatment with antibodies to CD32, CD64, CD36, and fucoidin, suggesting uptake by both scavenger receptors and Fc-gamma receptors. Furthermore, CRP treatment increased MMP-9 activity in macrophages compared with huSA, which was abrogated by inhibitors to p38 mitogen-activated protein kinase, extracellular signal-regulated kinase (ERK), and nuclear factor (NF)-kappaB but not Jun N-terminal kinase (JNK) before human CRP treatment. Because OxLDL uptake by macrophages contributes to foam cell formation and MMP release contributes to plaque instability, this study provides novel in vivo evidence for the role of CRP in atherosclerosis.

Acupressure for prevention of pre-operative anxiety: a prospective, randomised, placebo controlled study

Pre-operative anxiety is associated with many unwanted effects such as increased analgesic and anaesthetic requirement, postoperative pain and prolonged hospital stay. In the present study, we investigated the effects of acupressure on pre-operative anxiety and bispectral index (BIS) values. Seventy-six adults, ASA grade I and II, undergoing elective surgery, were randomly assigned to two equal groups. Group 1 (control) received acupressure at an inappropriate site and group 2 (acupressure) received acupressure at extra 1 point. The study was conducted during the pre-operative period and the duration of the study was 40 min (acupressure was applied for 10 min and thereafter patients were observed for another 30 min). Anxiety was recorded on a visual stress scale (VSS) at the start of the study and thereafter at 10 and 40 min. BIS was recorded at 0, 2, 5, 10, 12, 15, 30 and 40 min. The VSS decreased in both groups following pressure application for 10 min: median VSS (interquartile range) were 5 (1) vs. 8 (1) in the acupressure and 7 (0) vs. 8 (1) in the control groups (p < 0.001). Both pre-operative anxiety and BIS decreased significantly during acupressure application at extra 1 point (p < 0.001). Acupressure is effective in decreasing both pre-operative anxiety and BIS; however, these effects are not sustained 30 min following release of acupressure. Further studies are needed to elucidate the duration for which acupressure is effective.

Studies on the maturation of thymus stem cells. The effects of catecholamines, histamine and peptide hormones on the expression of T cell alloantigens

Studies have been performed in order to investigate the effects of catecholamines. histamine, peptide hormones and various other agents known to increase cellular adenosine 3':5'-cyclic monophosphate (cAMP) levels on the expression of Thy-1 and TL antigens on 14-day fetal thymic stem cells. It has been shown that the proportions of Thy-1 and TL positive cells, as detected by dye exclusion cytotoxicity tests, can be significantly increased by some of these agents and that these effects may be inhibited by beta adrenergic and H2 antagonists. The value of these tests as a means for studying normal thymic stem cell maturation and for investigating T cell deficiency is discussed.

Decreased number and impaired functionality of endothelial progenitor cells in subjects with metabolic syndrome: implications for increased cardiovascular risk

OBJECTIVE

Metabolic syndrome (MetS) is characterized by low-grade inflammation and confers an increased risk for cardiovascular disease. Endothelial progenitor cells (EPCs) are a measure of vascular health and are decreased in patients with various risk factors for cardiovascular disease (CVD). There is a paucity of data examining the EPC status especially in terms of their functionality in MetS subjects without diabetes or cardiovascular disease. We aimed to enumerate and functionally characterize EPCs in subjects with MetS in comparison to healthy controls.

METHODS

The study was performed at the University of California Davis Medical Center. Healthy controls (n=31) and MetS (n=46) subjects were included in the study. EPCs were enumerated in fasting blood by KDR/CD34 dual positivity. Functionality was assessed by the colony forming units (CFU) assay, migration and tubule formation.

RESULTS

Subjects with MetS had significantly decreased number of EPCs compared to control subjects. Furthermore, EPCs from MetS subjects depicted significantly impaired clonogenic capacity, i.e., decreased colony forming units, and impaired capacity to incorporate into tubular structures suggesting functional impairment of EPCs from MetS subjects.

CONCLUSIONS

We make the novel observation that MetS subjects without diabetes or CVD have decreased EPC number and impaired functionality as compared to control subjects. These findings could contribute to the increased CV risk in this population.

Phytic acid, in vitro protein digestibility, dietary fiber, and minerals of pulses as influenced by processing methods

The objective of this project was to determine the effect of various types of processing on selected nutrition related parameters of commonly consumed Indian pulses and soybean. Germination reduced the phytic acid content of chickpea and pigeonpea seeds by over 60%, and that of mung bean, urd bean, and soybean by about 40%. Fermentation reduced phytic acid contents by 26-39% in all these legumes with the exception of pigeonpea in which it was reduced by more than 50%. Autoclaving and roasting were more effective in reducing phytic acid in chickpea and pigeonpea than in urd bean, mung bean, and soybean. Germination and fermentation greatly increased the in vitro protein digestibility (IVPD). IVPD was only slightly increased by roasting and autoclaving of all legumes. Germination and fermentation also remarkably decreased the total dietary fiber (TDF) in all legumes. Autoclaving and roasting resulted in slight increases in TDF values. All the processing treatments had little effect on calcium, magnesium and iron contents.

Sulfhydryl-dependent attachment of Treponema denticola to laminin and other proteins

Attachment of Treponema denticola ATCC 35405 to laminin, a major basement membrane protein, and to other proteins was studied. Microdilution plates were coated with the proteins, and the attachment of T. denticola was measured by the enzyme-linked immunosorbent assay technique. Compared with bovine serum albumin (BSA), T. denticola had a high affinity to laminin, fibronectin, fibrinogen, and gelatin, as well as to type I and type IV collagens. Attachment to RGD peptide (Gly-Arg-Gly-Asp-Ser, the integrin recognition sequence) was only about 30% of that to laminin and was comparable to attachment to BSA. Tests with laminin fragments obtained through elastase digestion showed that the spirochetes attached well to an A-chain 140-kDa fragment involved in eukaryote cell attachment but did not attach to a 50-kDa fragment that includes the heparin binding site. Pretreatment of T. denticola with soluble laminin, fibronectin, gelatin, BSA, or fibrinogen had no effect on the attachment of the bacteria to laminin or fibronectin. A wide variety of compounds were tested for their possible inhibitory actions on the attachment. While most treatments of T. denticola ATCC 35405 had little or no effect on the attachment to proteins, sulfhydryl reagents p-chloromercuribenzoic acid (pCMBA) and oxidized glutathione inhibited the attachment by 70 to 99%, depending on the protein. When T. denticola was first allowed to attach to proteins, addition of pCMBA or oxidized glutathione could no longer reverse the attachment. Heat treatment of the spirochetes also markedly reduced the attachment to laminin, gelatin, and fibrinogen but not to BSA. Mixed glycosidase treatment of the spirochetes inhibited the attachment by 20 to 80%. None of the above treatments of the substrate proteins had any marked effect on the spirochete attachment. The results indicate that T. denticola has the capacity to bind to many different kinds of proteins by utilizing specific attachment mechanisms. The binding appears to involve protein SH groups and/or carbohydrate residues on the surface of T. denticola.

Antinutritional factors of chickpea and pigeonpea and their removal by processing

Protease inhibitors, amylase inhibitors, phytolectins, polyphenols, and oligosaccarides are important antinutritional factors of chickpea and pigeonpea. Research on these factors is reviewed and compared to those in other grain legumes. Both chickpea and pigeonpea are consumed in various forms as processed food. The effects of such processing practices as cooking, germination, and fermentation to reduce the levels of these antinutritional factors are also discussed.

Comparative biochemical and immunocytochemical studies reveal differences in the effects of Clostridium perfringens enterotoxin on polarized CaCo-2 cells versus Vero cells

Since most in vitro studies exploring the action of Clostridium perfringens enterotoxin (CPE) utilize either Vero or CaCo-2 cells, the current study directly compared the CPE responsiveness of those two cell lines. When CPE-treated in suspension, both CaCo-2 and Vero cells formed SDS-resistant, CPE-containing complexes of approximately 135, approximately 155, and approximately 200 kDa. However, confluent Transwell cultures of either cell line CPE-treated for 20 min formed only the approximately 155-kDa complex. Since those Transwell cultures also exhibited significant (86)Rb release, approximately 155-kDa complex formation is sufficient for CPE-induced cytotoxicity. Several differences in CPE responsiveness between the two cell lines were also detected. (i) CaCo-2 cells were more sensitive when CPE-treated on their basal surface, whereas Vero cells were more sensitive when CPE-treated on their apical surface; those sensitivity differences correlated with CPE binding the apical versus basolateral surfaces of these two cell lines. (ii) CPE-treated Vero cells released (86)Rb into both Transwell chambers, whereas CaCo-2 cells released (86)Rb only into the CPE-containing Transwell chamber. (iii) Vero cells express the tight junction (TJ) protein occludin but (unlike CaCo-2 cells) cannot form TJs. The ability of TJs to affect CPE responsiveness is supported by the similar effects of CPE on Transwell cultures of CaCo-2 cells and Madin-Darby canine kidney cells, another polarized cell forming TJs. Confluent CaCo-2 Transwell cultures CPE-treated for >1 h formed the approximately 200-kDa CPE complex (which also contains occludin), exhibited morphologic damage, and had occludin removed from their TJs. Collectively, these results identify CPE as a bifunctional toxin that, in confluent polarized cells, first exerts a cytotoxic effect mediated by the approximately 155-kDa complex. Resultant damage then provides CPE access to TJs, leading to approximately 200-kDa complex formation, internalization of some TJ proteins, and TJ damage that may increase paracellular permeability and thereby contribute to the diarrhea of CPE-induced gastrointestinal disease.

Balance and gait in total hip replacement: a pilot study

OBJECTIVE

Evaluation of balance, gait changes, sexual functions, and activities of daily living in patients with total hip replacement in comparison with healthy subjects.

DESIGN

A total of 30 patients were included in the study after total hip replacement. Balance was examined using dynamic posturography, and gait evaluation was done clinically. Sexual functions and activities of daily living were also assessed. A total of 30 healthy subjects of comparable age and sex served as a control group.

RESULTS

Dynamic balance and gait differed significantly in both the groups. Despite capsulectomy, no significant difference was observed on testing proprioception. In the sensory organization tests with difficult tasks, patients needed more sensory input from vision and vestibular sense, despite normal proprioceptive sense. Significant difference was observed for limits of stability, rhythmic weight shifts, and for gait variables other than walking base. Some of the patients had major difficulties with sexual functions and activities of daily living.

CONCLUSIONS

Compared with the healthy age- and sex-matched controls, patients with total hip replacement did not have any proprioceptive deficit. Patients required extrasensory input, and there was a delayed motor response. Gait and dynamic balance results also indicated the motor deficit and required a compensatory strategy. Restoration of the postural control in these patients is thus essential. Necessary training is required for balance, gait, and activities of daily living, and proper sexual counseling is necessary in postoperative care.

Variability in phytic acid content and protein digestibility of grain legumes

Several genotypes, number given within parenthesis, of chickpea, pigeonpea, urd bean, mung bean and soybean, differing in seed characteristics were analyzed for phytic acid, in vitro protein digestibility (IVPD), protein, total phosphorus, and seed size. Phytic acid contents and IVPD values differed significantly among and within these species. Phytic acid content (mg/g) was the highest in soybean (36.4) followed by urd bean (13.7), pigeonpea (12.7), mung bean (12.0) and chickpea (9.6). On an average, phytic acid constituted 78.2 percent of the total phosphorus content and this percentage figure was the highest in soybean and the lowest in mung bean. In vitro protein digestibility (IVPD) of pigeonpea and chickpea genotypes varied from 60.4 to 74.4 percent and 65.3 to 79.4 percent, respectively. The IVPD values of genotypes of mung bean, urd bean and soybean ranged from 67.2 to 72.2 percent, 55.7 to 63.3 percent and 62.7 to 71.6 percent, respectively. There was a significant negative correlation between phytic acid and IVPD of these genotypes. Phytic acid was significantly and positively correlated with protein but the magnitude of correlation was very low in chickpea and pigeonpea. Results indicate that the genotypes of pulses with low phytic acid content could be identified and used in breeding program to improve their nutritive value and utilization.

Enrichment of vitronectin- and fibronectin-like proteins in NaCI-adapted plant cells and evidence for their involvement in plasma membrane-cell wall adhesion

Cells of tobacco adapted to grow in high concentrations of NaCl develop tight zones of adhesion between the plasma membrane and cell wall, revealed by concave plasmolysis in osmotic solutions. Unadapted cells exhibit mostly convex plasmolysis and exhibit little or no adhesive character. Wall-less protoplasts isolated from the adapted cells retain the complementary adhesive character and adhere tightly to each other, whereas protoplasts from unadapted cells do not. The hexapeptide gly-arg-gly-asp-ser-pro, in which the arg-gly-asp represents the integrin-binding domain of several animal extracellular matrix proteins,specifically blocks adhesion of the protoplasts. A control hexapeptide, gly-arg-gly-glu-ser-pro, is ineffective in blocking adhesion. Tobacco proteins immunologically related to human vitronectin were found in cell walls and membranes of unadapted and NaCI adapted cells, but the total extractable vitronectin-like protein was enriched in the adapted cells. Tobacco proteins immunologically related to human fibronectin were found in membranes and cell walls of NaCI adapted cells but not in those from unadapted cells.Our observations indicate that plant cells possess cell-matrix adhesion complexes similar to animal cells, and these adhesion complexes accumulate ingrowth-limited cells adapted to saline stress.

Transcription initiation is controlled by three core promoter elements in the hgl5 gene of the protozoan parasite Entamoeba histolytica

Entamoeba histolytica is a single cell eukaryote that is the etiologic agent of amoebic colitis. Core promoter elements of E. histolytica protein encoding genes include a TATA-like sequence (GTATTTAAAG/C) at -30, a novel element designated GAAC (GAACT) that has a variable location between TATA and the site of transcription initiation, and a putative initiator (Inr) element (AAAAATTCA) overlying the site of transcription initiation. The presence of three separate conserved sequences in a eukaryotic core promoter is unprecedented and prompted examination of their roles in regulating transcription initiation. Alterations of all three regions in the hgl5 gene decreased reporter gene activity with the greatest effect seen by mutation of the GAAC element. Positional analysis of the TATA box demonstrated that transcription initiated consistently 30-31 bases downstream of the TATA region. Mutation of either the TATA or GAAC elements resulted in the appearance of new transcription start sites upstream of +1 in the promoter of the hgl5 gene. Mutation of the Inr element resulted in no change in the site of transcription initiation; however, in the presence of a mutated TATA and GAAC regions, the Inr element controlled the site of transcription initiation. We conclude that all three elements play a role in determining the site of transcription initiation. The variable position of the GAAC element relative to the site of transcription initiation, and the multiple transcription initiations that resulted from its mutation, indicate that the GAAC element has an important and apparently novel role in transcriptional control in E. histolytica.