Interaction of c-myc with transforming growth factor alpha and hepatocyte growth factor in hepatocarcinogenesis

Double transgenic mice bearing fusion genes consisting of mouse albumin enhancer/promoter-mouse c-myc cDNA and mouse metallothionein 1 promoter-human TGF-alpha cDNA were generated to investigate the interaction of these genes in hepatic oncogenesis and to provide a general paradigm for characterizing the interaction of nuclear oncogenes and growth factors in tumorigenesis. Coexpression of c-myc and TGF-alpha as transgenes in the mouse liver resulted in a tremendous acceleration of neoplastic development in this organ as compared to expression of either of these transgenes alone. The two distinct cellular reactions that occurred in the liver of the double transgenic mice prior to the appearance of liver tumors were dysplastic and apoptotic changes in the existing hepatocytes followed by emergence of multiple focal lesions composed of both hyperplastic and dysplastic cell populations. These observations suggest that the interaction of c-myc and TGF-alpha, during development of hepatic neoplasia contributes to the selection and expansion of the preneoplastic cell populations which consequently increases the probability of malignant conversion. These studies have now been extended to examine the interaction of hepatocyte growth factor (HGF) with c-myc during hepatocarcinogenesis in the transgenic mouse model. While sustained overexpression of c-myc in the liver leads to cancer, coexpression of HGF and c-myc in the liver delayed the appearance of preneoplastic lesions and prevented malignant conversion. Similarly, tumor promotion by phenobarbital was completely inhibited in the c-myc/HGF double transgenic mice whereas phenobarbital was an effective tumor promoter in the c-myc single transgenic mice. The results indicate that HGF may function as a tumor suppressor during early stages of liver carcinogenesis, and suggest the possibility of therapeutic application for this cytokine. Furthermore, we show for the first time that interaction of c-myc with HGF or TGF-alpha results in profoundly different outcomes of the neoplastic process in the liver.     

Role of bradykinin B2 receptors in neonatal kidney growth

OBJECTIVES: As the incidence of prostate cancer in the United States exceeds 330,000 in 1997, increasingly more men are faced with treatment choices for which there is no clear approach. At every stage of disease, these treatment choices may involve clinically equivalent modalities that differ in side effects and impact upon quality of life (QOL). Comprehensive, yet efficient, questionnaires are needed to measure QOL in patients with prostate cancer. METHODS: Developed as a disease-specific adjunct to the Functional Assessment of Cancer Therapy (FACT) measurement system, a 12-item prostate cancer subscale (PCS) was developed and tested in three independent samples: a subscale development sample (n = 43), validity sample 1 (n = 34), and validity sample 2 (n = 96). The 12 items ask about symptoms and problems specific to prostate cancer. These questions are added to the general (FACT-G) instrument, thereby comprising a 47-item questionnaire. RESULTS: Internal consistency of the PCS ranged from 0.65 to 0.69, with coefficients for FACT-G subscales and aggregated scores ranging from 0.61 to 0.90. Concurrent validity was confirmed by the ability to discriminate patients by disease stage, performance status, and baseline prostate-specific antigen (PSA) level. Sensitivity to change in performance status and PSA score over a 2-month period suggested that some subscales of the FACT-Prostate (P) (including the PCS) are sensitive to meaningful clinical change. CONCLUSIONS: Our findings support use of the FACT-P as a meaningful component of QOL evaluation in men undergoing therapy for prostate cancer.     

Genomic organization of the human TIMP-1 gene. Investigation of a causative role in the pathogenesis of X-linked retinitis pigmentosa 2

PURPOSE: To evaluate the role of TIMP-1 in inherited retinal degeneration. METHODS: The genomic structure of the TIMP-1 gene was established and male patients with x-linked retinitis pigmentosa 2 from five families were screened for sequence alterations by direct sequencing in all exons, exon-intron boundaries, and the 5' upstream region of the gene. RESULTS: TIMP-1 appears to be expressed in the retina at low levels and consists of six exons spanning a genomic region of approximately 4.5 kb on Xp11.23. No disease-specific sequence alterations were identified. A site substitution in exon 5 was observed in samples from control subjects and patients, but it did not alter the amino acid sequence of the protein product. CONCLUSIONS: The results of this study exclude mutations in the TIMP-1 coding sequence, splice sites, and the 5' upstream region as a cause of retinal degeneration in x-linked retinitis pigmentosa 2. However, an as yet unidentified regulatory element that lies outside these intervals may be implicated. The role of this tightly regulated protein in the normal functioning of the retina has yet to be determined.     

High-resolution crystal structures of delta5-3-ketosteroid isomerase with and without a reaction intermediate analogue

Bacterial Delta5-3-ketosteroid isomerase (KSI) catalyzes a stereospecific isomerization of steroid substrates at an extremely fast rate, overcoming a large disparity of pKa values between a catalytic residue and its target. The crystal structures of KSI from Pseudomonas putida and of the enzyme in complex with equilenin, an analogue of the reaction intermediate, have been determined at 1.9 and 2.5 A resolution, respectively. The structures reveal that the side chains of Tyr14 and Asp99 (a newly identified catalytic residue) form hydrogen bonds directly with the oxyanion of the bound inhibitor in a completely apolar milieu of the active site. No water molecule is found at the active site, and the access of bulk solvent is blocked by a layer of apolar residues. Asp99 is surrounded by six apolar residues, and consequently, its pKa appears to be elevated as high as 9.5 to be consistent with early studies. No interaction was found between the bound inhibitor and the residue 101 (phenylalanine in Pseudomonas testosteroni and methionine in P. putida KSI) which was suggested to contribute significantly to the rate enhancement based on mutational analysis. This observation excludes the residue 101 as a potential catalytic residue and requires that the rate enhancement should be explained solely by Tyr14 and Asp99. Kinetic analyses of Y14F and D99L mutant enzymes demonstrate that Tyr14 contributes much more significantly to the rate enhancement than Asp99. Previous studies and the structural analysis strongly suggest that the low-barrier hydrogen bond of Tyr14 (>7.1 kcal/mol), along with a moderate strength hydrogen bond of Asp99 ( approximately 4 kcal/mol), accounts for the required energy of 11 kcal/mol for the transition-state stabilization.     

Expression of differential nitric oxide synthase isoforms in human normal gastric mucosa and gastric cancer tissue

The present study investigated the expression and distribution of three isoforms of nitric oxide synthase (NOS) in different anatomical regions of the human stomach and in gastric neoplastic tissues by immunohistochemistry using specific antibodies. Intracellular localization of individual isoenzymes of NOS was detected in normal gastric mucosa. Gastric cancer tissues had a marked reduction of all three NOS isoforms expression. The expression of the endothelial NOS, neuronal NOS and inducible NOS in the tumor tissue was significantly lower than in normal gastric mucosa (P = 0.01, P = 0.02, P < 0.01, respectively). In the tumor tissue the expression of inducible NOS was significantly lower than the expression of both constitutive forms of NOS (P < 0.01). There was a tendency to higher expression of both constitutive forms of NOS in earlier stages T2 of the tumor compared to advanced T4 tumor. In contrast, the expression of inducible NOS was higher than in the advanced T4 tumor than in the earlier stages T2 of the tumor. The mapping of the expression of endothelial NOS, neuronal NOS and inducible NOS in human stomach showed higher expression of NOS isoforms in the distal third than in the proximal third of the stomach (P = 0.03, P = 0.04, P = 0.01, respectively). We conclude that there is greater expression of NOS in the stomach corpus and in antrum than in the proximal third of the normal human stomach mirroring the anatomical predilection of common pathological changes in this part of the human stomach. Furthermore, there was loss of the expression of individual isoenzymes in gastric neoplasms.     

Coexpression of Bcl-2, c-Myc, and p53 oncoproteins as prognostic discriminants in patients with colorectal carcinoma

Lanepitant is a high-affinity, selective neurokinin-1 receptor (NK-1) and is effective in the dural inflammation model of acute migraine. Lanepitant 30, 80, and 240 mg given orally was evaluated in a double-blind, placebo-controlled crossover study to determine its effect in reducing migraine pain and severity of associated symptoms. Outpatients treated four migraine headaches of moderate or severe pain intensity with study drug according to a randomization schedule. They recorded their pain intensity and severity of migraine-associated symptoms at 30, 60, 90, and 120 min. Although 53 patients were randomly allocated to a treatment sequence, only 40 patients completed all treatments. There was no statistically significant difference in improvement in migraine pain at any time for any of the treatments. Additionally, there was no change in severity of migraine-associated symptoms associated with lanepitant therapy. No adverse events could be attributed to lanepitant. Lanepitant was ineffective orally in treating acute migraine in this trial. This may be due to poor bioavailability during a migraine attack. Alternatively, the neurogenic inflammation hypothesis may not apply to migraine.     

Primary pulmonary hypertension

Justification of early treatment of nocturnal enuresis is founded in the negative psychological impact on the child. In fact nocturnal enuresis delays early autonomy and socialisation by decreasing in self-esteem and self-confidence. Nocturnal enuresis classification is the preliminary step to correct therapy. Enuresis must be classified as primary (never acquired nocturnal control) or secondary (at least 6 months of dry nights). A child is also classified as having monosymptomatic enuresis if she/he experienced only night wetting and symptomatic enuresis if she/he experienced night wetting associated with diurnal voiding symptoms (urinated > or = 7 times a day, urgency, damp pants, squatting, holding the perineum, sitting on one heel). Monosymptomatic patients must be treated with desmopressin nasal spray at the daily dose of 20 micrograms at bed time. If the reduction of at least the 50% of the basal number of the wet nights is not achieved, the dosage must be increased until 40 micrograms. For patients affected by rhinitis or asthma, desmopressin is now available in tablets. In symptomatic patients desmopressin therapy must be associated to oxybutinin (5 mg x 2). Therapy interruption must be gradual with desmopressin reduction of 10 micrograms every 30 days. In symptomatic patients oxybutinin must be introduced only at bed time. The efficacy of the drugs depends on the therapy length. The highest percentage of success is obtained if the treatment is protracted for at least six months. Antidepressants are also used for nocturnal enuresis especially imipramine. The dosage varies between 0.5-1.5 mg/ kg/daily. As plasmatic levels are achieved only in 30% of treated patients, a 3-5 fold increase in suggested. Nevertheless these levels result in near toxic threshold concentration. Sporadic treatment purposes include amytriptiline, diclofenac sodicum, viloxsazine and methilphenidate if giggle incontinence is present. Non responders may be treated with alarm. If after 16 weeks of treatment no success is obtained alarm use must be interrupted.