The importance of erythroid expansion in determining the extent of apoptosis in erythroid precursors in patients with beta-thalassemia major

Beta-thalassemia major is characterized by ineffective erythropoiesis leading to severe anemia and extensive erythroid expansion. The ineffective erythropoiesis is in part due to accelerated apoptosis of the thalassemic erythroid precursors; however, the extent of apoptosis is surprisingly variable. To understand this variability as well as the fact that some patients undergoing allogeneic marrow transplantation are resistant to the myeloablative program, we attempted more quantitative analyses. Two groups of patients totaling 44 were studied, along with 25 healthy controls, and 7 patients with hemolysis and/or ineffective erythropoeisis. By 2 flow cytometric methods, thalassemic erythroid precursors underwent apoptosis at a rate that was 3 to 4 times normal. Because thalassemic marrow has between 5- to 6-fold more erythroid precursors than healthy marrow, this translated into an absolute increase in erythroid precursor apoptosis of about 15-fold above our healthy controls. In searching for the causes of the variability in thalassemic erythroid precursor apoptosis, we discovered tight direct correlations between the relative and absolute extent of apoptosis and the extent of erythroid expansion as measured either by the absolute number of marrow erythroid precursors or by serum soluble transferrin receptor levels. These results could mean that the most extreme rates of erythroid proliferation lend themselves to cellular errors that turn on apoptotic programs. Alternatively, extreme rates of erythroid hyperplasia and apoptosis might be characteristic of more severely affected patients. Lastly, extreme erythroid hyperplasia could generate such numbers of apoptotic erythroid precursors that marrow macrophages are overwhelmed, leaving more apoptotic cells in the sample.     

Visual acuity and visual field development after cryocoagulation in infants with retinopathy of prematurity

Visual development was studied in 10 very-low-birth-weight infants (less than 1500 g) with retinopathy of prematurity (ROP) stage 3+ who had been treated with cryocoagulation in both eyes. Binocular visual acuity (acuity cards method) and binocular visual fields (kinetic perimetry) were assessed repeatedly in the first year of life. At 12 months corrected age, visual acuity was normal in seven and impaired in three infants, who appeared to be severely myopic. Normal visual fields were found in eight infants at this age. The results indicate that cryotherapy in cases of ROP stage 3+ does not interfere with visual acuity development. The effect on visual field development needs further investigation.     

The effect of N-acetyl-L-cysteine on the viscosity of ileal neobladder mucus

N-acetyl-L-cysteine (NAC) proved to be an effective mucolytic in pulmonary secretions. Our goal was to investigate the in vitro effect of NAC on viscosity of ileal neobladder mucus. The urine of a patient with an ileal neobladder was collected during the first 7 days postoperatively and stored in a refrigerator. After precipitation, the urine was decanted. The residue was stirred to a homogeneous suspension. To samples of 4.5 ml mucus, 0.5 ml NAC 10% was added. To the control sample, 0.5 ml water was added. The samples were incubated in a water bath at 37 degrees C for 5, 30 and 60 min. Viscosity was measured in the Bohlin VOR Rheometer. The viscosity of the ileal neobladder mucus decreased quickly after incubating with NAC 10%. Viscosity increased slightly after I h of incubation. The viscosity in the control sample was higher than in the other incubated samples. NAC was found to decrease the viscosity of ileal neobladder mucus, supporting the in vivo experience that NAC can be useful in patients with an ileal neobladder to facilitate the evacuation of mucus by decreasing viscosity.     

Comparative effects of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers on blood pressure and the kidney

Many clinicians are uncomfortable about using angiotensin-converting enzyme (ACE) inhibitors or angiotensin II type 1 receptor blockers (AT(1)-blockers) to treat patients with renal disease because of concerns about increasing serum creatinine levels. However, the benefits of these medications, particularly their efficacy in slowing the progression of renal disease, outweigh such concerns. ACE inhibitors are effective in patients with type 1 diabetes and renal disease, as well as in those with nondiabetic renal disease and proteinuria >0.5 g/d. AT(1)-blockers slow the progression of diabetic nephropathy in patients with type 2 diabetes. Although these classes of medications should not be used in patients with severe renal insufficiency (e.g., glomerular filtration rate <20 mL/min), they may be beneficial in patients with mild-to-moderate renal insufficiency. Nonetheless, caution should be exercised in those with a glomerular filtration rate <30 mL/min, and serum creatinine and potassium levels should be checked approximately 1 week after starting treatment. There is also evidence suggesting that these medications lead to greater reductions in blood pressure and proteinuria when used in combination than when alone. The purpose of this paper is to review the mechanisms of action of these two classes of medication, as well as the experimental and clinical evidence that they slow the progression of renal disease.     

TCR reconstitution in Jurkat reporter cells facilitates the identification of novel tumor antigens by cDNA expression cloning

The identification of novel tumor antigens is of extreme importance for effective immunotherapy against cancer. A major obstacle in this field is the limited life span of tumor-specific cytotoxic T lymphocytes (CTLs) in vitro. Therefore we searched for a method to isolate the tumor specificity of these CTLs, i.e., their T-cell receptors (TCRs) and transfer it to an immortalized T-cell line. For this purpose, a TCR-negative Jurkat T-cell line was equipped with a nuclear factor of activated T cells (NFAT)-luciferase reporter construct to allow measurement of TCR-mediated activation. To establish the feasibility of this tumor-specific TCR transduction, we cloned the TCR genes of a known T-cell clone specific for the tumor antigen CAMEL (CTL-recognized antigen on melanoma) into a retroviral construct. Jurkat reporter cells transduced with this construct, Jrt-TCRalpha3beta5, were tested for their reactivity against CAMEL-expressing melanoma cells, peptide-loaded T2 cells and CAMEL-transfected COS-1 cells. The melanoma cell lines were poorly recognized, but peptide-pulsed and -transfected cells effectively stimulated NFAT signaling. The activation of TCR(+) Jurkat reporter cells was shown to be dependent on the antigen density on the target cells and the expression level of the coreceptor CD8 on the Jurkat cells. To verify the benefit of this TCR reconstitution method for identification of novel antigens, pools of the cDNA library from which CAMEL was originally cloned were transfected in COS-1 cells and screened with Jrt-TCRalpha3beta5. Identical cDNA pools were found that were positive with these cells and with the CAMEL-specific CTL clone. Our results illustrate that TCR-reconstituted Jurkat reporter cells are a useful tool in the identification of novel tumor antigens by cDNA expression cloning.     

金龙胶囊配合辨证用药治疗中晚期恶性肿瘤40例

1临床资料2003-12/2004-10采用北京建生药业生产的金龙胶囊配合辨证用药治疗中晚期癌症40例.Karnofsky评分≥40分,预计生存期>2 mo.     

Desensitization of soluble guanylate cyclase in renal cortex during endotoxemia in mice

Acute endotoxemic renal failure involves renal vasoconstriction, which presumably occurs despite increased nitric oxide (NO) generation by inducible NO synthase in the kidney. The present study examined the hypothesis that the renal vasoconstriction during endotoxemia occurs in part because of desensitization of soluble guanylate cyclase (sGC). Endotoxic shock was induced in male B6/129F2/J mice by an intraperitoneal injection of Escherichia coli lipopolysaccharide. The endotoxemia resulted in shock and renal failure as evidenced by a decrease in mean arterial pressure and an increase in serum creatinine and urea nitrogen. Serum NO increased in a time-dependent manner, reaching the highest levels at 24 h, in parallel with induction of inducible NO synthase protein in the renal cortex. In renal cortical slices obtained from endotoxemic mice, cyclic guanosine monophosphate (cGMP) increased significantly at 6 h and 15 h as compared with control but normalized at 24 h after injection of lipopolysaccharide. Incubation of renal cortical slices in the presence of a phosphodiesterase inhibitor isobutylmethylxantine did not alter the pattern of changes in cGMP. Incubation of renal cortical slices with 2 mM sodium nitroprusside resulted in a similar accumulation of cGMP in slices taken from control and endotoxemic mice at 6 h and 15 h. However, in slices from 24-h endotoxemic mice, accumulation of cGMP in response to sodium nitroprusside was significantly lower. This lower stimulability of sGC was not paralleled by a decrease in its abundance in renal cortex on immunoblot. Taken together, these results demonstrate a desensitization of sGC in renal cortex during endotoxemia, which may contribute to the associated renal vasoconstriction.