15-lipoxygenase-1 in colorectal cancer: a review

OBJECTIVE

Enzymes involved in the oxidative metabolism of n-6 polyunsaturated fatty acids, like lipoxygenase (LOX) and cyclooxygenase (COX), are significant in the pathogenesis of colorectal cancer. Of these enzymes, 15-LOX-1 is expressed in colon. Aim of this article is to describe the role and regulation of 15-LOX-1 in colorectal cancer and highlight its importance in cancer therapeutics.

METHODS

For our electronic literature research in PubMed and MEDLINE, key words related to 15-LOX-1 and colorectal cancer were used to find articles for this review.

RESULTS

From the evidences, we believe that 15-LOX-1 has anti-carcinogenic effects in colorectal cancer, dependent or independent of its metabolites, and is manifested through downstream pathways involving cGMP, PPAR, p53, p21 and NAG-1, increasing apoptosis and decreasing proliferation in cancer cells. Regulation of 15-LOX-1 expression is achieved at transcription level by global histone acetylation and may also be dependent on GATA-6, IL-4 and IL-13. Positive relationship exists between 15-LOX-1 and survival in colorectal cancer.

CONCLUSION

Evidences strongly support that therapeutic modulation of 15-LOX-1 may be a key to the treatment of colorectal cancer. However, it is still undecided whether the up-regulation of 15-LOX-1 alone can be sufficient to treat colorectal cancer and further studies are awaited.

Acute cytomegalovirus hepatitis in immunocompetent host

BACKGROUND

In inmunocompetent hosts, cytomegalovirus (CMV) infection is generally asymptomatic. It may however present as infectious mononucleosis. Serious complications have rarely been reported. We report three cases of acute CMV hepatitis in immunocompetent men for the first time from Bangladesh. All three presented to us with features of acute hepatitis of variable duration preceded by prodrome. Other probable causes of acute hepatitis were ruled out and none had any clinical stigmata of cirrhosis. All the three patients underwent uneventful recovery. Although more common in the immunocompromised, CMV can occasionally produce symptomatic hepatitis in the immunocompetent host. Disease is self limiting, but supportive measures are needed.

Fournier's gangrene: a dreadful disease

BACKGROUND

Although there is much consensus, certain controversies still exist regarding the pathology of Fournier's gangrene. The purpose of this study was to determine the prevalence of the disease in the catchment area of the three teaching hospitals, to identify the systemic predisposing factors and local aetiological factors, and to assess the recommended role of aggressive surgical debridement as a part of treatment.

MATERIALS AND METHODS

This prospective study was conducted in the surgical departments of three tertiary care hospitals of the Khyber Medical University, Peshawar, Pakistan, from 1 January 2002 to 30 June 2007. Detailed history and examination of all patients were carried out to reach the diagnosis of Fournier's gangrene. After initial resuscitation, patients were treated aggressively, including surgical debridement.

RESULTS

Sixty patients were studied in the study period. The male to female ratio was 5:1. The age range was 20-75 years with mean 47+17.4 (SD) years. The socioeconomic status of patients was poor (the average income was less than $50 per week) in 36 (60%) and 24 (40%) were middle class (the average income being $50-100 per week). Thirty-nine patients (65%) presented in the hot humid months of the year. Extent of the disease was scrotum in 18 patients (30%), perineum in 30 (50%) and abdominal wall in 12 (20%). Systemic predisposing factors identified in our study were diabetes mellitus in 20 (33.33%) patients, chronic alcohol abuse in two (3.33%) and long-standing steroid therapy in four (6.67%) while in 34 patients (56.67%) no cause was identified. The local aetiological origin of Fournier's gangrene was urogenital in 14 (23.33%) patients, anorectal in 10 (16.67%) and cutaneous in 8 (13.33%) and no local pathologies could be identified in 28 (46.67%) patients. The mean time interval between first symptom and initial treatment was 2.5 days with a range of 1-7 days. Number of debridement sessions per patient was 2-6 (mean, 3.15). Mean hospital stay was 31+7 (SD) with a range of 10-50 days. Morbidity was 80%. Four patients (6.67%) died. Three of these patients presented to hospital 5-6 days too late.

CONCLUSION

Fournier's gangrene is not an uncommon disease in South Asia. Systemic predisposition such as diabetes mellitus, long-standing steroid therapy, chronic alcoholism and even the hot humid season can contribute to this dreadful disease. Local causes in the form of urogenital, anorectal and cutaneous disorders may trigger this disease in some patients. Early recognition of disease and aggressive surgical debridement are the main treatments.

Phylogenetic analysis of ALAD and MGP genes related to lead toxicity

Experimental studies in our laboratory have established the role of delta-aminolevulinic acid dehydratase (ALAD) and matrix gamma-carboxyglutamic acid (MGP) gene polymorphisms in the etiology of lead toxicity. Polymorphisms in these genes influenced the levels of lead in subjects exposed to this metal. In extension to our studies, we aimed to investigate the possible role of these proteins in evolution by studying the phylogenetic relationship and divergence of ALAD and MGP genes using computational phylogenetic methods. The human ALAD and MGP protein sequences from various species were retrieved from Swiss-Prot database and were compared using Basic Local Alignment Search Tool. Multiple sequence alignment was carried out using ClustalW with defaults, and phylogenetic trees for both the genes were built using neighbor-joining method as in Mega software. Our study indicated that ALAD is a highly conserved protein with the same metal binding site distributed in all the phyla (from archaea to chordates). Phylogenetic analysis of MGP gene revealed that it had an important role in the evolution of endogenous skeleton in contrast to exoskeleton of insects. Occurrence of these genes in evolution with conserved metal binding sites strengthens the role of ALAD and MGP genes in regulating heme biosynthesis and mineralization, respectively, in evolution and helps in better understanding of lead poisoning.

Urethral venous malformation: an unusual cause of recurrent post-coital gross haematuria in association with haematospermia

Three cases of recurrent post-coital haematuria are described. Extensive protracted investigations pinpointed urethral varicosities as the likely cause. All patients were successfully treated with diathermy fulguration.

Phase II trial comparing folinic acid, fluorouracil, and gemcitabine (FFG) and FOLFOX4 regimens with added bevacizumab (B) in metastatic colorectal cancer (mCRC)

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Background: FOLFOX4 is a standard chemotherapy for mCRC. FFG has shown substantial activity in mCRC. This trial compared the safety and efficacy of FFG and FOLFOX4 regimens in patients (pts) with mCRC. B was added to each arm after FDA approval in 2004 as first-line treatment of mCRC. Methods: Pts with mCRC, chemonaïve except for adjuvant treatment, were randomized to two treatment arms: FFG given weekly for 6 weeks of an 8-week cycle; FOLFOX4 had a 2-week cycle. Pts in both groups received B at 5 mg/kg every 2 weeks. Treatment continued until disease progression. Planned enrollment was 150 pts. Primary endpoint was overall response rate (ORR); secondary endpoints included toxicity, overall survival (OS), and time to progression (TTP). Response was assessed by RECIST. Post-hoc analysis of disease control rate (DCR) was added. Results: Forty-two pts (18 pts given B) were randomized to each arm. Thirty-one cycles of FFG and 248 cycles of FOLFOX4 were delivered. FFG produced greater myelosuppression than FOLFOX4. Two cases each of MI and DVT were observed in the FOLFOX4(B) subgroup; one pt had DVT with FFG alone. The incidence of gastrointestinal hemorrhage was low and similar for FFG and FOLFOX4. Peripheral neuropathy was highest in the FOLFOX4(B) subgroup. ORR and DCR were significantly greater for FOLFOX4(B) than for FFG(B). Median TTP and OS were not statistically different for FFG and FOLFOX4 groups. The trial was stopped due to low enrollment; planned statistical power was not achieved. Conclusions: FFG and FOLFOX4 regimens were generally well tolerated, with greater neuropathy in FOLFOX4 and greater myelosuppression in FFG. ORR was greatest in the FOLFOX4(B) subgroup. TTP and OS results comparing FFG and FOLFOX4 groups were inconclusive due to low enrollment. Rapid changes in mCRC “standard of care” during this trial may have constrained pt accrual.

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The role of "ischemic ST-segment counterpoise" in rendering the response of exercise electrocardiogram falsely negative

Exercise electrocardiogram (ECG) has a high rate of false negative results in comparison with simultaneously performed thallium-201 perfusion scintigraphy, particularly in patients with single-vessel coronary artery disease, low exercise workload, inadequate heart rate rise, and resting ECG abnormalities. We present the case of a patient in whom thallium-201 SPECT scintigram revealed equally extensive and severe myocardial ischemia in two myocardial planes opposite each other. The accompanying exercise ECG did not disclose ischemic changes despite the adequacy of heart rate rise in this patient with severe right and left anterior descending coronary artery disease. We propose, as an explanation for this phenomenon, that in this patient the ischemic ST-segment vectors of equal magnitude and direction but of opposite sense, generated during stress, cancelled each other ("ischemic ST-segment counterpoise"), thus rendering the exercise ECG normal.

Neonatal myocardial infarction and the role of extracorporeal membrane oxygenation

Acute myocardial infarction is a cause of neonatal collapse. The diagnosis is suggested by ischaemic electrocardiography, raised cardiac enzymes and deteriorating cardiac function and should be considered in severe neonatal cardiac dysfunction without other identifiable causes. This paper presents four cases of neonatal myocardial infarction treated with veno-arterial extracorporeal membrane oxygenation (VA ECMO) for cardiorespiratory support. The paper illustrates that left ventricular function may recover after neonatal myocardial infarction if it can be supported for long enough, and that early ECMO referral may be of benefit.

First Report of a Novel Fusarium Species Causing Yellowing Decline of Sugar Beet in Minnesota

In the United States, yellows disease of sugar beet (Beta vulgaris), which causes wilt, early death, and yield reduction, is caused primarily by Fusarium oxysporum f. sp. betae (3,4), but F. graminearum (2) has also been implicated. During the past 3 years, a similar disease causing yellowing and severe decline appeared in some sugar beet fields of central and southwest Minnesota planted with cultivars resistant to yellows. The disease has become a concern to the local sugar beet industry, which produces 56% of sugar beets in the United States. From 2005 to 2007, isolations were made from sugar beets collected in commercial fields and from a Fusarium screening nursery showing symptoms of yellowing, interveinal chlorosis, scorching, stunting, vascular discoloration of the taproot, and early death of plants. Of 96 Fusarium isolates recovered and used in root-dip inoculation trials in the greenhouse, 58 were pathogenic to sugar beets. On the basis of morphology, 12 were identified as F. oxysporum, 6 as F. graminearum, and 40 as a novel Fusarium species. The remaining 38 isolates were nonpathogenic. All three pathogenic Fusarium species were isolated from taproots, but only the novel Fusarium was isolated from petioles. In culture, the novel Fusarium exhibited a bright orange color on the underside of potato dextrose agar medium and produced micro- and macroconidia sparsely. Hyphal tip isolates of all novel Fusarium isolates were pathogenic, causing typical yellowing symptoms and plant death to the Fusarium yellows susceptible sugar beet cv. VDH46177 in replicated greenhouse trials. Isolates were successfully reisolated from the symptomatic plants, fulfilling Koch's postulates. Restriction fragment length polymorphism (RFLP) endonuclease digestion patterns (Alu1, Fnu4HI, HaeIII, and HhaI) of the internal transcribed spacer (ITS) region of 40 pathogenic novel isolates showed a distinct pattern compared with known Fusarium species. Thin layer chromatography analysis of 13 novel isolates detected the type A trichothecenes neosolaniol and 4,15-diacetoxyscirpenol. Partial sequences of the translation elongation factor 1-α (TEF) from 12 single-spored novel Fusarium isolates were generated. BLAST analysis of the TEF sequence against the FUSARIUM-ID (1) and GenBank databases did not match any known Fusarium species. On the basis of pathogenicity, morphology, RFLP patterns, mycotoxin production, and TEF sequence analysis it appears that this is a new species of Fusarium, but additional multilocus phylogenetic analyses are warranted. The natural occurrence of this novel Fusarium pathogen in sugar beet may have implications in breeding for resistance to Fusarium yellows, since yellow decline has been observed in purportedly Fusarium-tolerant cultivars in the Minnesota and North Dakota production regions. References: (1) D. M. Geiser et al. Eur. J. Plant Pathol. 110:473, 2004. (2) L. E. Hanson. Plant Dis. 90:686, 2006. (3). L. E. Hanson. Plant Dis. 90:1554, 2006. (4) C. E. Windels et al. Plant Dis. 89:341, 2005.

The exercise-related rise in plasma cobalt levels after metal-on-metal hip resurfacing arthroplasty

Wear of metal-on-metal bearings causes elevated levels of cobalt and chromium in blood and body fluids. Metal-on-metal bearings have two distinct wear phases. In the early phase, the wear rate is high. Later, it decreases and the bearing enters a steady-state phase. It is expected that as the wear rates decline, the level of cobalt detected in plasma will also decrease. We studied the baseline and exercise-related cobalt rise in 21 patients (13 men and eight women) with a mean age of 54 years (38 to 80) who had undergone successful hip resurfacing at a mean of 44 months (10 to 96) earlier. Our results showed that circulating baseline cobalt levels were not significantly correlated with the time since implantation (r = 0.08, p = 0.650). By contrast, the exercise-related cobalt rise was directly correlated with the inclination angle of the acetabular component (r = 0.47, p = 0.032) and inversely correlated with the time since implantation (r = −0.5, p = 0.020).

Inclination of the acetabular component should be kept less than 40° to decrease the production of wear debris.