Effect of alpha-thalassemia on sickle-cell anemia linked to the Arab-Indian haplotype in India

Two population groups from Western India with a high prevalence of the beta(S) gene, one tribal (Valsad) and the other nontribal (Nagpur), were studied. The beta(S) gene frequency in both populations was similar (0.22 vs. 0.23), but not the clinical expression of sickle-cell anemia (SS): the sickle homozygotes in the tribal group appeared to have a mild clinical course, whereas the majority in the nontribal group exhibited a more severe clinical phenotype. Both tribal and nontribal SS patients had a similarly high mean hemoglobin (Hb)F expression (18.5% vs. 15.5%) and a high number of F cells (72.3% vs. 66.6%). DNA analysis of the beta-globin gene cluster region revealed that in these two populations, this portion of DNA was identical with and corresponded to the typical Arab-Indian haplotype. Nevertheless, in heterozygotes, the mean beta(S) expression was lower (27.9%) in the tribal as compared to the nontribal group (35.5%). The major epistatic factor distinguishing the milder presentation in tribals vs. a more severe manifestation in nontribals was the very high frequency (0.97) of the alpha-thalassemia gene in the former as compared to the latter (0.24). We conclude that the phenotypic expression of sickle-cell anemia, linked to the Arab-India haplotype and expressing similar levels of HbF and F cells, is not uniformly mild in India and that alpha-thalassemia is a powerful and additional epistatic factor in the Indian subcontinent.

Molecular diversity and evolution of blaTEM genes encoding beta-lactamases resistant to clavulanic acid in clinical E. coli

The molecular diversity of inhibitor-resistant TEM (IRT) enzymes was explored using a strategy which involved DNA amplification by polymerase chain reaction (PCR), analysis of restriction fragment length polymorphism (RFLP), and direct nucleotide sequencing. The study of plasmid-borne genes from 27 strains, resistant to amoxicillin and beta-lactamase-inhibitor combinations, identified mutations resulting in amino acid change at positions 69, 244, 275, and 276 known to be associated with the IRT phenotype and a mutation at nucleotide position 162 in the promoter region. These mutations were found to lie on two different gene sequences, described here as "TEM-1B like" and "TEM-2 like" restriction linkage groups. Further analysis, of nucleotide sequences of promoter and coding regions of the beta-lactamases, confirmed that a given mutation causing IRT phenotype could be associated with two different gene sequence frameworks and two different causal mutations could lie on identical gene sequence framework. These data argue in favor of convergent phenotypic evolution of IRT enzymes under the selective pressure imposed by the intensive clinical use of beta-lactam-beta-lactamase inhibitor combinations.

Isolation and phylogenetic characterization of Ebola viruses causing different outbreaks in Gabon

Three outbreaks of Ebola hemorrhagic fever have recently occurred in Gabon. Virus has been isolated from clinical materials from all three outbreaks, and nucleotide sequence analysis of the glycoprotein gene of the isolates and virus present in clinical samples has been carried out. These data indicate that each of the three outbreaks should be considered an independent emergence of a different Ebola virus of the Zaire subtype. As in earlier Ebola virus outbreaks, no genetic variability was detected between virus samples taken during an individual outbreak.

Homocystinuria presenting as fatal common carotid artery occlusion

A patient with homocystinuria presenting with fatal cerebral infarction that resulted from left common carotid artery occlusion is reported. This 13-year-old, healthy and intelligent girl presented with progressive cerebral infarction. Angiography revealed total occlusion of the left common carotid artery and stenosis of the right common carotid artery. Distal stenosis of bilateral vertebral arteries was also observed. Initially Takayasu arteritis with unusual manifestation was considered. However, later investigations revealed homocystinuria was the underlying cause. The sudden onset of fatal stroke as the initial clinical presentation of homocystinuria, as observed in this previous healthy teenager, is noteworthy. We suggest metabolic screening for homocystinuria when treating a patient with unusual vascular lesions.

Adenovirus-mediated increase of exogenous and inhibition of endogenous fosB gene expression in cultured pulmonary arterial smooth muscle cells

Modification of gene expression in pulmonary arterial smooth muscle cells (PASMCs) could be a valuable tool for investigating the role of specific gene products in normal and pathological PASMC growth, and a novel potential therapy for pulmonary vascular diseases. To examine the direct role of fosB protein in PASMC growth, adenovirus (Ad) vectors were used to transfer sense or antisense full-length fosB cDNAs to cultured PASMCs to modify fosB expression, and investigate the effects of this modification on PASMC growth. The full-length fosB cDNA under the control of the cytomegalovirus (CMV) early gene promoter was constructed into an E1 region-deleted, replication-deficient human type 5 Ad vector in either sense or antisense orientation. Forty-eight hours after infection with the sense construct (Ad.S. fosB) at 3 plaque-forming units per cell (pfu/cell). PASMCs expressed abundant fosB mRNA and fosB protein. FosB protein was detected by immunohistochemistry in approximately 95% of the infected cells. PASMCs infected with Ad.S.fosB at ratios of 0.1, 0.2, 0.5, 1.3, and 10 pfu/cell showed a dose-dependent increase in fosB mRNA expression, with half-maximal and maximal expression at 1 and 10 pfu/cell, respectively. The increase in fosB mRNA expression was detected as early as 8 h and persisted for 25 days after infection. Forty-eight hours after infection with the antisense construct (Ad.A.fosB) at 3 pfu/cell, very low levels of fosB mRNA were detected by Northern blotting, in which the double-stranded fosB cDNA was labeled and used as a hybridization probe. FosB protein was undetectable by Western blotting or immunocytochemical analyses in the Ad.A.fosB infected cells. Cytopathical effects were observed when PASMCs were infected with either Ad.S.fosB or Ad.A.fosB at ratios of 10 pfu/cell or higher. Infection of serum-deprived PASMCs with Ad.S.fosB or Ad.A.fosB alone at 3 pfu/cell did not affect cellular growth. These results show that adenoviral vectors containing sense or antisense fosB cDNA expression units can be used to effectively modify fosB gene expression. Although changes in fos-B gene expression did not affect cellular growth, this model system offers a very effective method for elucidating the biological roles of other gene products and studying the pathways of PASMC gene regulation and signal transduction.

Inhibition of macrophage nitric-oxide production and Ia-expression by docosahexaenoic acid, a constituent of fetal and neonatal serum

PROBLEM

We previously demonstrated profound inhibition of macrophage activation in the murine placenta in vivo. Given the importance of macrophages both in initiating cellular immunity by presenting antigen in the context of Ia to CD4+ T cells, and in killing cellular targets by producing nitric oxide (NO), inhibition of macrophage functions in the placenta may account for the increased susceptibility of the placenta to infection. We have also showed that docosahexaenoic acid (DHA), at concentrations present in the fetal circulation, has a major role in inhibiting macrophage Ia-expression and NO production in the placenta. The concentration of DHA in fetal serum perfusing the placenta is 50x higher than in the adult. DHA has previously been reported to profoundly affect prostanoid production, to be metabolized by lipoxygenases, and to affect lipoxygenases. We now determine if these activities of DHA account for its inhibition of macrophage NO production and Ia-expression.

METHODS

Murine macrophages were cultured in vitro, exposed to IFN gamma endotoxin, DHA, and various eicosanoids, and their ability to produce NO or express Ia determined.

RESULTS

Although the cyclooxygenase inhibitor, indomethacin, did inhibit NO production, DHA inhibited by a different mechanism. DHA further inhibited NO production by macrophages exposed to doses of indomethacin known to maximally inhibit prostanoid production. Stable, biologically active prostanoids did not reverse the inhibitory effect of DHA. Although DHA is metabolized by lipoxygenases, the lipoxygenase inhibitor NDGA did not reverse the inhibition of either NO production nor Ia expression. This indicates that lipoxygenase products of DHA did not mediate inhibition. NDGA itself inhibited NO production and Ia expression. However, DHA did not inhibit by inhibiting lipoxygenase activity because DHA further inhibited macrophages exposed to doses of DHA known to maximally inhibit lipoxygenases. Furthermore, stable biologically active analogs of lipoxygenase products did not reverse DHA inhibition. DHA also did not inhibit by preventing PAF production because PAF did not reverse inhibition of NO production.

CONCLUSION

DHA did not inhibit Ia-expression or NO production via its known effects on eicosanoid or PAF metabolism, nor by being metabolized by lipoxygenases.

Differential regulation of Ia expression and antigen presentation by listeriolysin-producing versus non-producing strains of Listeria monocytogenes

Listeria monocytogenes is an intracellular bacterial pathogen. A single gene product, listeriolysin (LLO), is critical for the induction of protective immunity. We now show that listeria that produce functional LLO augment Ia expression by macrophages and are better presented to a Th1, CD4+ anti-listeria T cell line. We used two genetically engineered strains of listeria which differed only in their ability (Ly+) or inability (Ly-) to produce functional LLO. Ia-negative murine macrophages ingested either Ly+ or Ly-, and then were stimulated by interferon-gamma (IFN-gamma). Increasing numbers of live Ly+, but not Ly-, augmented IFN-gamma-induced Ia expression. Ly+ by itself did not induce Ia expression. Heat-killed Ly+ and Ly- did not augment IFN-gamma-induced Ia expression. The abundance of Ia on the macrophage cell surface is one major determinant of antigen presentation to CD4+ T cells. Consistent with their ability to augment la expression, Ly+ were better presented than Ly- to a CD4+, Th1, anti-listeria T cell line. When macrophages and T cells were from different inbred mouse strains, antigen presentation required identity at the class II region of the MHC gene complex. This indicated that antigen presentation occurred via Ia molecules. The increased ability of macrophages to present Ly+ is a product of the macrophage-listeria interaction, not a property of the T cell tine 86. If Ia-negative macrophages ingested Listeria and were then stimulated by IFN-gamma, Ly+ was presented more efficiently than Ly-. On the other hand, if Ia-positive macrophages ingested Listeria, then Ly+ and Ly- were presented equally well to T cells. Altogether our data is consistent with the hypothesis that macrophages interact differently with Ly+, and that this contributes to the ability of only live Ly+ to induce protective immunity.

Transcription of the murine iNOS gene is inhibited by docosahexaenoic acid, a major constituent of fetal and neonatal sera as well as fish oils

Macrophage activation is deficient in the fetus and neonate when the serum concentrations of docosahexaenoic acid (DHA) are 150 microM, or 10-50-fold higher than in the adult. We now show that DHA inhibits production of nitric oxide (NO) by macrophages stimulated in vitro by IFNgamma plus LPS, or by IFNgamma plus TNFalpha. The half-maximal inhibitory activity of DHA was approximately 25 microM. There were strict biochemical requirements of the fatty acid for inhibition. Polyenoic fatty acids with 22 carbons were more inhibitory than those with 20 carbons. Among 22-carbon fatty acids, those with a greater number of double bonds and a double bond in the n-3 position were more inhibitory. DHA was the most inhibitory of the polyenoic acids we tested. Inducible nitric oxide synthase (iNOS) is the enzyme responsible for the production of NO by macrophages. NO production is initiated after new iNOS enzyme is synthesized following transcription of the iNOS gene. In macrophages stimulated by IFNgamma plus LPS, DHA inhibited accumulation of iNOS mRNA, as measured by Northern blotting, and iNOS transcription, as measured by nuclear run-on assays. We transfected RAW 264.7 macrophages with a construct containing the iNOS promoter fused to the chloramphenicol acetyl transferase gene. DHA inhibited activation of this promoter by IFN gamma plus LPS. By inhibiting iNOS transcription in the fetus and neonate, DHA may contribute to their increased susceptibility to infection.

Pancreas transplantation for diabetes mellitus

Pancreas transplantation has become a viable option for the patient wi th insulin-dependent diabetes mellitus with progressive renal failure. The most common type of pancreas transplantation is a simultaneous pancreas and kidney transplantation performed from a single cadaver donor (SPK). The next most common is pancreas transplantation after successful kidney transplantation (PAK). A few centers are performing pancreas transplantation alone (PTA) in diabetic recipients without renal disease but who have significant complications from their diabetes. Pancreas transplantation is associated with a higher morbidity than kidney transplantation alone. Most pancreas transplantation centers report a significant increase in acute rejection, which can lead to increased hospitalization and risk of opportunistic infection. In addition, the early era of pancreas transplantation was associated with significant surgical complications. However, with bladder drainage of the pancreas exocrine secretions, the surgical complication rate has decreased significantly. Despite medical and surgical complications, the overall results for pancreas transplantation are excellent, with 1 -year graft survival of 75% for SPK transplantations and 48% for PAK and PTA transplant recipients. The effects of a pancreas transplantation on the secondary complications of diabetes have been studied extensively. Most studies have shown a modest improvement in secondary complications with the exception of diabetic retinopathy. The major benefit of pancreas transplantation appears to be enhanced quality of life for patients successfully transplanted. For these reasons, the Kidney-Pancreas Committee of the American Society of Transplant Physicians believes the current results of pancreas-kidney transplantation justify its use as a valid option for insulin-dependent diabetic transplant recipients.

Prenatal diagnosis of beta-thalassaemia mutations using the reverse dot blot technique

BACKGROUND

Beta-thalassaemia is the most common genetic disorder among Indians and a number of mutations causing this disease have been reported. Since effective treatment of thalassaemia major is complicated and very expensive, prenatal diagnosis has become an important option for those at risk of having an affected foetus. We report the use of a rapid hybridization method called 'reverse dot blot' for detection of specific mutations of the beta-globin gene.

METHODS

DNA was obtained from a 12-week-old foetus by chorionic villus sampling and was amplified using specific primers by the polymerase chain reaction and analysed by the reverse dot blot test. Results were available within 36 hours after sampling.

RESULT

The father and mother were found to be heterozygous for codon 15 (G-A) mutation of the beta-globin gene. The foetus was normal.

CONCLUSION

Reverse dot blot is a rapid and reliable technique for mutation detection in the beta-globin gene and can be useful for antenatal diagnosis.

Augmentation or inhibition of IFN-gamma-induced MHC class II expression by lipopolysaccharides. The roles of TNF-alpha and nitric oxide, and the importance of the sequence of signaling

MHC class II expression on macrophages is one determinant of Ag presentation and the vigor of CD4+ T cell immunity. We show that LPS may either inhibit or augment IFN-gamma-induced MHC class II on macrophages depending on the sequence of the IFN-gamma and LPS signals. LPS inhibited MHC class II when added simultaneously with IFN-gamma, but augmented class II expression when added after IFN-gamma. Inhibition was due to nitric oxide (NO), which was only produced if LPS was given simultaneously with IFN-gamma. However, even when NO production was inhibited, LPS given simultaneously with IFN-gamma did not augment MHC class II expression. This suggests that LPS delivers different signals when given simultaneously vs after IFN-gamma. LPS augmentation of class II expression was functionally important because it correlated with increased Ag presentation. Augmentation by LPS of IFN-gamma-induced class II expression by macrophages has not been previously reported. We found that TNF-alpha, like LPS, inhibited IFN-gamma-induced class II expression if NO was produced, but augmented it in the absence of NO formation. Studies with a neutralizing anti-TNF-alpha Ab, however, indicate that LPS augmentation of MHC class II did not require TNF-alpha. LPS augmentation involved a different mechanism than IFN-gamma induction of MHC class II. LPS augmentation occurred at a post-transcriptional level, whereas IFN-gamma-induction occurred at the level of gene transcription. LPS augmentation was apparent after 2 h of stimulation by LPS, while IFN-gamma induction of class II expression required more than 8 h.

Augmentation or inhibition of IFN-gamma-induced MHC class II expression by lipopolysaccharides. The roles of TNF-alpha and nitric oxide, and the importance of the sequence of signaling

MHC class II expression on macrophages is one determinant of Ag presentation and the vigor of CD4+ T cell immunity. We show that LPS may either inhibit or augment IFN-gamma-induced MHC class II on macrophages depending on the sequence of the IFN-gamma and LPS signals. LPS inhibited MHC class II when added simultaneously with IFN-gamma, but augmented class II expression when added after IFN-gamma. Inhibition was due to nitric oxide (NO), which was only produced if LPS was given simultaneously with IFN-gamma. However, even when NO production was inhibited, LPS given simultaneously with IFN-gamma did not augment MHC class II expression. This suggests that LPS delivers different signals when given simultaneously vs after IFN-gamma. LPS augmentation of class II expression was functionally important because it correlated with increased Ag presentation. Augmentation by LPS of IFN-gamma-induced class II expression by macrophages has not been previously reported. We found that TNF-alpha, like LPS, inhibited IFN-gamma-induced class II expression if NO was produced, but augmented it in the absence of NO formation. Studies with a neutralizing anti-TNF-alpha Ab, however, indicate that LPS augmentation of MHC class II did not require TNF-alpha. LPS augmentation involved a different mechanism than IFN-gamma induction of MHC class II. LPS augmentation occurred at a post-transcriptional level, whereas IFN-gamma-induction occurred at the level of gene transcription. LPS augmentation was apparent after 2 h of stimulation by LPS, while IFN-gamma induction of class II expression required more than 8 h.

[Effect of Chinese traditional prescription "Shen Yang" on the immune function of oral squamous cells carcinoma patients.]

This report tries to compare the immunologic function of being take the Chinese medicine "Fu-Fang Shen Yang" or placebo C which is based on randomized clinical trials after operation for 238 cases of oral squamous cancer.DNCB test is for observable index.The results as follows:DNCB position rate of 1 "Shen Yang" group is significantly increased to compare with the placebo C group,after 3m(P<0.01) 6m (P<0.001).Two groups are significantly increased after one year.This suggestion that "Fu-Fang Shen Yang" can enhance immunologic function after operation fro oral squamous cells carcinoma patients.

[The Chinese traditional treatment with "ShengYang" prescription as a post-operative auxiliary method using on the oral squamous cells carcinoma patients.]

This paper observed the clinic investigation.Which prove the relationship among the Chinese dialectical fur condition pulse condition,dialectical divided into types and survival time,immunity function before and after therapy,which will provide scientific basis and new train of thinking for recovery of stomatological carcinoma patient following operation.These patients according to dialectical type.were divided into type of feeble kidney and type of mixed excess and deficiency syndrome that the survive time compare with control group through treat by statistics,were P<0.05.The positive cases of immunity response of administration group were more increased than control group, the rate was 22.2%,maintenance and decrease rate were 7.5% and 14.6% compare with control group,with multiple factor computer analysis in two groups.There is some evidence that the traditional Chinese prescription of "ShengYang" treat in tumor patients with the type of feeble kidney and type of mixed excess an deficiency syndrome were remarkably regulate the immunity function and promote the action of anti tumor.For recovery therapy after tumor operation which reach a fairly action.

Differential regulation of TNF-alpha production by listeriolysin-producing versus nonproducing strains of Listeria monocytogenes

Only Listeria monocytogenes that produce listeriolysin O (LLO) elicit protective immunity. Given the importance of tumor necrosis factor alpha (TNF-alpha) in anti-Listeria immunity, we have investigated TNF-alpha production by macrophages after they ingested live LLO-producing compared to LLO-non-producing bacteria. We used two genetically engineered strains of Listeria that differed only in their ability (Ly+) or inability (Ly-) to produce LLO. Ly+ and Ly- caused the same kinetics of increased mRNA abundance for TNF-alpha during the first 90 min after phagocytosis. However, only Ly+ caused sustained transcription of TNF-alpha mRNA, and this may account for the increased release of TNF-alpha. The transcriptional inhibitor 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB) prevented the sustained abundance of cytokine mRNA 20 h after ingestion of Ly+. In addition, nuclear run-on assays indicated sustained transcription of TNF-alpha genes only after ingestion of Ly+. LLO itself was not responsible for the ability of Ly+ to stimulate the sustained transcription of the TNF-alpha genes. Instead, LLO may allow Listeria to survive within macrophages so that other bacterial products cause sustained TNF-alpha gene transcription. Both Ly+ and Ly- produced molecules, isolated by 50% ammonium sulfate, that induced cytokine production. In conclusion, we now report that Ly+ causes sustained transcription of the TNF-alpha gene and production of TNF-alpha by macrophages in vitro. We speculate that the TNF-alpha may activate endothelium and thus allow the recruitment of T cells to sites of infection. This may contribute to the ability of only LLO-producing Listeria to induce protective immunity.

Delayed thromboxane or tumor necrosis factor-alpha, but not leukotriene inhibition, attenuates prolonged pulmonary hypertension in endotoxemia

The early phase of endotoxin-induced acute hemodynamic disturbances and hypoxemia is mediated by various factors, including eicosanoids and tumor necrosis factor-alpha (TNF alpha). Thromboxane A2 is the major mediator of the early pulmonary hypertension associated with endotoxemia, but the mechanisms underlying the prolonged hemodynamic disturbances observed in ongoing endotoxemia are not well understood. The authors used a chronically instrumental young piglet model to determine the roles of several eicosanoids and of TNF alpha in the prolonged endotoxin-induced pulmonary hypertension and other cardiovascular derangements. Animals were given 40 micrograms/kg endotoxin intravenously per hour for 30 minutes, followed by 20 micrograms/kg per hour. In all animals, persistent pulmonary hypertension, lowered cardiac output, any hypoxemia developed during endotoxin infusion. After 3 hours of endotoxin infusion, randomly ordered infusions of 1 mg/kg dazmegrel (a thromboxane A2 synthesis inhibitor), 5mg/kg nordihydroguaiaretic acid (a 5-lipoxygenase inhibitor), and 20 mg/kg pentoxifylline (A TNF alpha inhibitor) were given intravenously at 30-to-60-minute intervals. Dazmegrel and pentoxifylline lowered pulmonary arterial pressure and resistance and raised arterial oxygen tension. Cardiac output increased significantly after pentoxifylline. These hemodynamic effects persisted for 30-60 minutes, despite continued endotoxin infusion. The elevated plasma concentrations of thromboxane B2 and TNF alpha returned toward preendotoxin baseline values after dazmegrel and pentoxifylline treatment, respectively. No beneficial effects were noted after administration of nordihydroguaiaretic acid. Based on these results, both thromboxane A2 and TNF alpha, but not 5-lipoxygenase products, play active roles in prolonged endotoxin-induced pulmonary hypertension and hypoxemia in young piglets. Combined thromboxane A2 and TNF alpha blockade may be clinically useful in treatment of advanced sepsis in neonates.

[Study of toxicity of iodophor,glutaradehyde and chlorhexidine to L929 Cells.]

We comparatively studied the toxicity of iodophor,glutaradehyde and chlorhexidine in different concentration and time.The result shows that the toxicity of iodophor to L929 cells is the lowest in all kinds of drug concentration and action time is much lower than that of glutaradehyde and chlorhexidine(P<0.05) with prolonging time.It indicates that iodophor can be used to oral diseases therapy with lower concentration.

Point mutation in the pribnow box, the molecular basis of beta-lactamase overproduction in Klebsiella oxytoca

Klebsiella oxytoca mutants resistant to a variety of beta-lactams were obtained in vitro on aztreonam. Constitutive beta-lactamase production was much higher in the mutants than in the susceptible strains (75-fold). The only difference observed in these mutants compared with the susceptible strains were point mutations in the Pribnow box: a transversion (G-->T) in the first base for one mutant or a transition (G-->A) in the fifth base of the -10 consensus sequence for the other three mutants. The transcriptional output of the beta-lactamase gene (blaOXY) from the mutants was significantly higher than that of the blaOXY gene from the susceptible strains.

Polyamines and NMDA receptors modulate pericapillary astrocyte swelling following cerebral cryo-injury in the rat

Four hours following cryo-injury rat cerebral pericapillary astrocytes from the perilesional area were markedly swollen occupying 17% of the pericapillary space as compared to 11% in sham operated controls. Ornithine decarboxylase activity and polyamine levels were increased over sham controls. The astrocytic swelling, the percentage of the pericapillary space occupied by astrocytic processes, and polyamine levels were reduced to near control levels by the following: (1) alpha-difluoromethylornithine; (2) Ifenprodil; and (3) MK-801. alpha-Difluoromethylornithine is a specific inhibitor of ornithine decarboxylase, Ifenprodil is an inhibitor of the polyamine binding site on the n-methyl-d-aspartate receptor, and MK-801 is an antagonist to n-methyl-d-aspartate binding to the n-methyl-d-aspartate receptor. Addition of putrescine, the product of ornithine decarboxylase activity, reversed the effect of alpha-difluoromethylornithine and restored the pericapillary swelling. Putrescine did not affect the MK-801-induced reduction in pericapillary astrocytic swelling. Therefore, polyamines and the n-methyl-d-aspartate receptor modulate excitotoxic responses to cryo-injury in pericapillary cerebral astrocytes.