Transplantation of embryonic dopamine neurons for severe Parkinson's disease

BACKGROUND

Transplantation of human embryonic dopamine neurons into the brains of patients with Parkinson's disease has proved beneficial in open clinical trials. However, whether this intervention would be more effective than sham surgery in a controlled trial is not known.

METHODS

We randomly assigned 40 patients who were 34 to 75 years of age and had severe Parkinson's disease (mean duration, 14 years) to receive a transplant of nerve cells or sham surgery; all were to be followed in a double-blind manner for one year. In the transplant recipients, cultured mesencephalic tissue from four embryos was implanted into the putamen bilaterally. In the patients who received sham surgery, holes were drilled in the skull but the dura was not penetrated. The primary outcome was a subjective global rating of the change in the severity of disease, scored on a scale of -3.0 to 3.0 at one year, with negative scores indicating a worsening of symptoms and positive scores an improvement.

RESULTS

The mean (+/-SD) scores on the global rating scale for improvement or deterioration at one year were 0.0+/-2.1 in the transplantation group and -0.4+/-1.7 in the sham-surgery group. Among younger patients (60 years old or younger), standardized tests of Parkinson's disease revealed significant improvement in the transplantation group as compared with the sham-surgery group when patients were tested in the morning before receiving medication (P=0.01 for scores on the Unified Parkinson's Disease Rating Scale; P=0.006 for the Schwab and England score). There was no significant improvement in older patients in the transplantation group. Fiber outgrowth from the transplanted neurons was detected in 17 of the 20 patients in the transplantation group, as indicated by an increase in 18F-fluorodopa uptake on positron-emission tomography or postmortem examination. After improvement in the first year, dystonia and dyskinesias recurred in 15 percent of the patients who received transplants, even after reduction or discontinuation of the dose of levodopa.

CONCLUSIONS

Human embryonic dopamine-neuron transplants survive in patients with severe Parkinson's disease and result in some clinical benefit in younger but not in older patients.

Freezing phenomenon in patients with parkinsonian syndromes

Freezing is a common symptom in parkinsonian syndromes, but its association with different causes of parkinsonism as well as with other symptoms has never been investigated. We conducted a database survey of the occurrence of freezing in parkinsonism. Of 347 patients with a clinical diagnosis of parkinsonism other than idiopathic Parkinson's disease and with specific data regarding freezing, 158 patients had freezing (46%). Freezing was significantly associated with progression of the disease as rated on the Hoehn & Yahr scale [odds ratio (OR), 1.69; p < 0.004]. Gender was not a risk factor for the development of freezing. Patients with drug-induced parkinsonism were at a very low risk for developing freezing (p < 0.00001; OR, 0.1). Freezing was found in a high frequency in patients with vascular parkinsonism (57%), normal-pressure hydrocephalus (56%), and generally in the group of patients who had parkinsonism resulting from neurodegenerative diseases (progressive supranuclear palsy, multiple system atrophy, and corticobasal ganglionic degeneration; 45%). Freezing was significantly associated with the presence of dementia, incontinence, and tachyphemia (OR, 2.01, 1.7, and 5.09, respectively).

The late-stage diagnosis of colorectal cancer: demographic and socioeconomic factors

OBJECTIVES

This study described factors related to colorectal cancer stage at diagnosis.

METHODS

Logistic regression analyses were used on data from the New York State Tumor Registry and US Census area-level social class indicators.

RESULTS

After the effects of other predictors were controlled for, the odds of late-stage cancer increased as age decreased; women and African Americans were significantly more likely to have late stage than men and Whites; and individuals living in areas of low socioeconomic status (SES) were significantly more likely to be diagnosed at late stage than those living in higher SES areas. Stratified analyses showed that living in a low SES area was the most important determinant of stage for all age, race, gender and source-of-care groups.

CONCLUSIONS

While all populations would benefit from the systematic use of screening socioeconomically disadvantaged groups may also benefit from targeted screening.

Factors associated with peripheral blood stem cell yield in volunteer donors mobilized with granulocyte colony-stimulating factors: the impact of donor characteristics and procedural settings

Peripheral blood stem cells (PBSCs) are increasingly used as the source of hematopoietic stem cells, but there are large variations in harvest outcome between individuals mobilized by granulocyte colony-stimulating factor (G-CSF). We examined the effects of donor characteristics and procedure factors on the day 1 CD34+ cell yield in 373 unrelated healthy donors. G-CSF was administered subcutaneously at a planned dose of 8.3 to 11 microg/kg daily for 5 days, followed by harvest started on day 5 of G-CSF treatment. Of the 373 donors, 159 (42.6%) had the radial artery as the inlet access for harvest. Poor day 1 cell yield was defined as <10x10(6) CD34+ cells/L of processed blood for the first apheresis; 62 donors (16.6%) did not attain this threshold. The male donors had significantly higher yields at harvest compared with the female donors. The female donors had higher CD34+ cell yields if the circulation access was through an artery than if is was through a vein. In a multiple regression analysis, donor age, sex, body mass index (BMI), preharvest white blood cell and circulating immature cell counts, access type, and flow rate correlated with day 1 yield. Female sex, older age, venous access, and a higher flow rate were significantly associated with greater risk for a day 1 poor yield of CD34+ cells (odds ratio=3.0074, 1.045, 4.3362, and 1.1131, respectively). A higher BMI may decrease the risk (odds ratio=0.8472). In donors at higher risk for poor CD34+ cell yield, strategies for increasing CD34+ cells must be considered.

Impact of access and social context on breast cancer stage at diagnosis

This study examined the impact of individual demographic characteristics (age, race/ethnicity, and type of reporting hospital), together with measures of social context, including area of residence socioeconomic status (SES), change in SES, and access to screening (area mammography capacity), on breast cancer stage at diagnosis among New York City residents diagnosed between 1980 and 1985. Three logistic regression models evaluated the impact of individual variables, social context variables, and both classes of variables combined on the outcome of having late-stage (regional or distant) compared to early-stage (local) cancer. The logistic regression models indicated that women aged 50 to 64 years were independently more likely to have late-stage cancer than those younger or older. Controlling for individual and social context variables, African American women were 25 percent more likely than White women to have late-stage breast cancer (p < 0.0001); higher odds seen in the individual model for Hispanic women disappeared after controlling for area SES. In the combined model, women diagnosed from public hospitals were 44 percent more likely to have late-stage disease than those diagnosed in nonpublic settings (p < 0.0001). In both the social context and combined models, area mammography capacity was a significant independent predictor of stage (p = 0.016); area-level SES, but not change in SES, was independently related to late-stage disease (p = 0.002). These data suggest that breast cancer control activities should more actively ensure adequate access to screening, particularly for minorities, populations living in socioeconomically disadvantaged areas, and those cared for in the public sector.

Overexpressed hPTTG1 promotes breast cancer cell invasion and metastasis by regulating GEF-H1/RhoA signalling

Human pituitary tumour-transforming gene 1 (hPTTG1) is an oncogenic transcription factor that is overexpressed in many tumour types, especially tumours with metastatic abilities. However, how hPTTG1 overexpression drives metastasis is not yet clear. As a transcription factor, hPTTG1 may promote metastasis by activating target genes that are involved in the metastatic process. Here, we showed that Rho guanine nucleotide exchange factor-H1 (GEF-H1) was transcriptionally activated by hPTTG1, thereby promoting breast cancer metastasis. Luciferase reporter analyses and chromatin immunoprecipitation (ChIP) assays showed that hPTTG1 directly bound and activated the GEF-H1 gene promoter. In this study, RNA interference-mediated knockdown of hPTTG1 in highly metastatic breast tumour cells decreased GEF-H1 expression and RhoA activation, thereby reducing cell motility and invasion, and interfering with cytoskeletal remodelling in vitro, and impairing the tumour metastasis in vivo. The restoration of GEF-H1 expression in hPTTG1-knockdown cells rescued the hPTTG1-knockdown effects on cytoskeletal changes in vitro and tumour metastasis in vivo. Conversely, ectopic expression of hPTTG1 in non-metastatic breast tumour cells induced cytoskeletal rearrangements, and allowed these cells to metastasise in a mouse model by orthotopic implantation. In human tumour samples, hPTTG1 expression was also correlated to GEF-H1 expression in aggressive breast carcinoma. Altogether, these findings definitively establish a role for hPTTG1 in activating the GEF-H1/RhoA pathway as a newly identified mechanism in breast cancer metastasis.

Fungal ribotoxins: a family of naturally engineered targeted toxins?

alpha-Sarcin, mitogillin, and restrictocin are small (approximately 17 kDa) basic robosome-inactivating proteins (RIPs) produced by the Aspergilli that catalytically inactivate the large ribosomal subunits of all organisms tested to date. These three fungal ribotoxins act as specific ribonucleases by hydrolyzing one single phosphodiester bond in the universally conserved alpha-sarcin domain of 23-28S rRNAs and are among the most potent inhibitors of protein synthesis known. Previous molecular studies of ribotoxins indicated that they belong to the superfamily of ribonucleases and analysis of the mitogillin gene employing PCR-mediated site-specific mutagenesis suggests that certain domains in ribotoxins, which share homologies with motifs in ribosome-related proteins, may be responsible for the targeting of ribotoxins to the ribosome. The applications of the ribotoxins as tools in research and their uses as therapeutic and diagnostic agents are also reviewed in this paper.

Targeting breast and cervical cancer screening to elderly poor black women: who will participate? The Harlem Study Team

BACKGROUND

Factors associated with participation in breast and cervix cancer screening among elderly black women of low socioeconomic status were determined.

METHODS

Data from a baseline cross-sectional random survey were used together with data on whether screening was subsequently completed or refused. The subjects were a random sample of women attending an urban public hospital primary care clinic for routine medical care with a birth year of 1924 or earlier.

RESULTS

Among the 271 women in the study group, 70% completed screening. Stated intent was the strongest predictor of participation; women who intended to have both mammography and Pap testing were 2.7 times more likely to participate than those who intended to have neither test (95% confidence interval 1.4, 4.9; P < 0.01), controlling for age, insurance status, and level of chronic illness. Women who had more than three chronic illnesses were twice as likely to participate than those with three or fewer illnesses (95% confidence interval 1.1, 3.4 P < 0.02), controlling for the remaining variables. Other variables, including age, history of a recent screening examination, attitudes, or knowledge, were not related to participation. Stated intent was the only variable that predicted compliance with both mammography and Pap smear completion in separate regression models for the individual tests.

CONCLUSION

A high proportion of elderly, socioeconomically disadvantaged black women will participate in cancer screening when it is offered in a primary care setting. Further research on behavioral intentions should be conducted to refine interventions designed to enhance the use of early cancer detection among vulnerable population groups.

Ribotoxins are a more widespread group of proteins within the filamentous fungi than previously believed

Alpha-sarcin, restrictocin and mitogillin are the best known members of the family of fungal ribotoxins. In recent years, new members of this family have been discovered and characterised. In this work, we study the occurrence of ribotoxins among different species of fungi. The presence of ribotoxins has been identified in some new species by means of genetic studies, as well as expression and activity assays. The ribotoxin genes have been partially sequenced, and demonstrate a high degree of similarity. These studies demonstrate that these toxins are more widespread than previously considered. This is surprising, considering the ribotoxins are such specific and potent toxins, of unknown biological function. These studies confirm the hypothesis that these proteins are naturally engineered toxins derived from ribonucleases of broad substrate specificity.

Mammography and Papanicolaou smear use by elderly poor black women. The Harlem Study Team

OBJECTIVE

To describe factors related to the use of mammography and Papanicolaou smears in low-income women aged 65 or more years to guide development of future interventions.

DESIGN

A cross-sectional survey.

SETTING AND PATIENTS

Elderly Black women attending a public hospital medical clinic.

MEASUREMENTS

Information obtained in a face-to-face interview of a random sample of patients.

RESULTS

Four-hundred and forty-five women (94%) consented to be interviewed; 74% reported a mammogram, and 85% reported a Papanicolaou smear in the past, although these early-detection tests were not obtained with any regularity after age 65. Concordance between self-reported screening use and blind chart review was more than 90%. The major reasons for non-use of both screening tests were that a physician hadn't recommended them or that the women didn't know they needed them. Levels of knowledge about breast and cervix cancer were low; 68% believed bumping or bruising the breast caused cancer, and only 25% knew that cancer risk increased with advancing age. In logistic regression models, health status, provider type, perceived benefit, life satisfaction, and knowledge of test intervals were each significantly associated with mammogram use. Age, health status, education, perceived susceptibility and benefit, life satisfaction, and knowledge of test intervals were independently related to Pap use (P < .05).

CONCLUSION

This study illustrates that elderly, poor, minority women who are regular health-care users do use mammography and Pap smear screening services. Incorporating screening into routine primary care and physician and patient education could enhance the use of early cancer detection procedures in this age group.

Measurement of left ventricular ejection fraction and volumes with three-dimensional reconstructed transesophageal ultrasound scans: comparison to radionuclide and thermal dilution measurements

A transesophageal, ultrasonic cardiac imaging probe was built that incorporated a mechanism for changing the angle of the imaging plane of a conventional phased array in a precise and known manner. This probe was used to acquire an angular spatial sequence of two-dimensional images of the left ventricular cavity over a series of cardiac cycles by sweeping the imaging plane through it stepwise. The endocardial borders of these images were manually outlined off-line and the application of a three-dimensional reconstruction algorithm was then used to compute the left ventricular end-diastolic and end-systolic volumes and ejection fraction. A study was conducted with seven anesthesized dogs to compare ultrasonic determinations by this method with determinations and measurements made using radionuclide and thermal dilution methods. Comparison of 33 ejection fractions, measured by the ultrasonic volume method and by the gated blood pool radionuclide approach, yielded a correlation coefficient of 0.87 and a standard error of the estimate of 5.7% measured over a range of 10% to 58% (average, 40%). Comparison of the ultrasonically measured volumes with those calculated from stroke volume (derived from thermal dilution cardiac output measurement) and ejection fraction (measured by radionuclide technique) produced a correlation coefficient of 0.92 and a standard error of the estimate of 10.3 mL over a range of 18 to 130 mL (average, 56 mL). The accuracy of volume and ejection fraction measurements with this new ultrasonic method seems comparable to that of other currently used clinical approaches such as radionuclide and angiography.

BAG-i expression in human breast cancer: interrelationship between BAG-1 RNA, protein, HSC70 expression and clinico-pathological data

BAG-1 (BCL-2 athanogene-1), a multifunctional protein which associates with steroid hormone receptors (including the oestrogen receptor) and the anti-apoptotic BCL-2 protein, regulates steroid hormone-dependent transcription and apoptosis. Direct interaction with 70 kD heat-shock proteins, HSC70 and HSP70, may mediate the diverse functions of BAG-1. Immunohistochemistry was used to examine the expression of BAG-1 and HSC70 in 160 cases of invasive breast cancer. BAG-1 was expressed in 92% of cases; most tumours exhibited cytoplasmic BAG-1, while a smaller proportion also had nuclear immunostaining. There was a significant inverse correlation between histological grade and nuclear BAG-1 expression, with higher-grade tumours tending to have reduced nuclear BAG-1 expression, but there was no association with cytoplasmic BAG-1. There was also no significant correlation between nuclear or cytoplasmic BAG-1 expression and oestrogen receptor positivity. Since BAG-1 may be influenced by hormonal background, the relationship between grade and oestrogen receptor was examined separately in pre-menopausal and post-menopausal women. The statistically significant correlation between nuclear BAG-1 expression and low tumour grade was strong in pre-menopausal, but not apparent in postmenopausal women. A statistically significant correlation was observed between cytoplasmic, but not nuclear, BAG-1 expression and oestrogen receptor status in pre-menopausal, but not postmenopausal, women. There was no correlation between BAG-1 protein expression and RNA, suggesting that important post-transcriptional mechanisms control BAG-1 expression in vivo. HSC70 was also detected in the majority (97%) of cases, although expression was not correlated with BAG-1 levels, oestrogen receptor status or tumour grade. Overall survival in cases with high levels of nuclear BAG-1 expression was improved, though not significantly. These results are consistent with the hypothesis that BAG-1 plays an important but variable role in breast cancers developing in pre-menopausal and post-menopausal women.

Molecular dissection of mitogillin reveals that the fungal ribotoxins are a family of natural genetically engineered ribonucleases

Mitogillin and the related fungal ribotoxins are highly specific ribonucleases which inactivate the ribosome enzymatically by cleaving the 23-28 S RNA of the large ribosomal subunit at a single phosphodiester bond. The site of cleavage occurs between G4325 and A4326 (rat ribosome numbering) which are present in one of the most conserved sequences (the alpha-sarcin loop) among the large subunit ribosomal RNAs of all living species. Amino acid sequence comparison of ribotoxins and guanyl/purine ribonucleases have identified domains or residues likely involved in ribonucleolytic activity or cleavage specificity. Fifteen deletion mutants (each 4 to 8 amino acid deletions) in motifs of mitogillin showing little amino acid sequence homology with guanyl/purine ribonucleases were constructed by site-directed mutagenesis. Analyses of the purified mutant proteins identified those regions in fungal ribotoxins contributing to ribosome targeting and modulating the catalytic activity of the toxin; some of the identified motifs are homologous to sequences in ribosomal proteins and elongation factors. This mutational study of mitogillin together with the recently published x-ray structure of restrictocin (a close relative of mitogillin) supports the hypothesis that the specific cleavage properties of ribotoxins are the result of natural genetic engineering in which the ribosomal targeting elements of ribosome-associated proteins were inserted into nonessential regions of T1-like ribonucleases.

Chemotherapy with cisplatin and continuous infusion of 5-fluorouracil and bleomycin for recurrent and metastatic nasopharyngeal carcinoma in Taiwan

Twenty-five patients with metastatic and/or recurrent nasopharyngeal carcinoma were treated with cisplatin 20 mg/m2/day on days 1-5 i.v. with hydration; 5-fluorouracil (5-FU) 1,000 mg/m2/day by continuous infusion (CI); and bleomycin 15 mg/m2 on day 1 also by CI. These cycles were repeated every 4 weeks. Twenty-three (92%) had distant metastases. Bone was the most frequently involved site (72%), followed by lungs (44%) and liver (40%). More than half the patients (14/25) presented with at least 3 organ sites involved or had local T3/T4 or N3 lesions with a distant metastasis. The median time from relapse to start of chemotherapy was 7.5 months. We observed 1 (4%) complete response (CR), and 9 (36%) partial responses (PR). The objective response rate (CR + PR) was 40%. Hematologic toxicities were frequently encountered. Twenty (80%) patients experienced leukopenia during the treatment courses and 9 (36%) had severe (grade 3 or 4) leukopenia. Eight patients had grade 3 or 4 infections. Two of them died of sepsis and 1 succumbed to uncontrolled pneumonia. The objective response rate was inferior to other series. Possible explanation included longer delay before initiation of definitive treatment, larger tumor burdens, higher severe hematologic toxicity and lower dosage of bleomycin. The results suggested metastatic and/or recurrent nasopharyngeal carcinoma is chemosensitive, however, for patients with large tumor burdens, more intensive chemotherapy regimens with support of hematopoietic growth factors may be required to achieve a better control.

Ascorbic acid stimulates production of glycosaminoglycans in cultured fibroblasts

The effect of ascorbic acid on collagen synthesis is well characterized. Proteoglycans and their attached glycosaminoglycans are components of the extracellular matrix closely associated with collagen fibers. We examined whether ascorbic acid also plays a role in glycosaminoglycan production. Synthesis and deposition of glycosaminoglycans into the extracellular matrix and secretion into the media were followed in human skin fibroblasts cultured in the presence and absence of ascorbic acid. Specific glycosaminoglycans were identified and quantitated by differential enzyme digestion, ion-exchange column chromatography, and cellulose-acetate electrophoresis. No major qualitative changes in glycosaminoglycans were observed. However, quantitatively, synthesis of glycosaminoglycans increased 30 to 90%, and deposition into the extracellular matrix increased 80% in the presence of ascorbic acid. This effect was only in part secondary to decreased levels of collagen, and the diminished capacity of underhydroxylated collagen to bind proteoglycans. The effect of ascorbic acid on extracellular macromolecules is thus more pervasive than previously assumed.

Comparison of in vitro preconditioning responses of isolated pig and rabbit cardiomyocytes: effects of a protein phosphatase inhibitor, fostriecin

Calcium tolerant pig and rabbit cardiomyocytes were isolated using retrograde aortic perfusion of nominally calcium-free collagenase. Preconditioning protocols used 1 or 3x10-min episodes of ischemic pelleting or pre-incubation with 100 micro M adenosine, followed by a 15-min post-incubation and 180-240-min ischemic pelleting. Control cells were incubated and washed in parallel with the experimental groups. Injury was assessed by determination of cell morphology, trypan blue permeability following osmotic swelling, lactate and HPLC analysis of adenine nucleotides. Preconditioned pig cardiomyocytes had a reduced rate of ischemic contracture, but protection occurred without conservation of ATP. Preconditioned rabbit cardiomyocytes were protected without significant changes in rates of ischemic contracture or ATP depletion. Incubation of ischemic cells with the protein phosphatase inhibitor, fostriecin, at PP2A-selective concentrations (0.1-10 micro M), mimicked preconditioning in both rabbit and pig cardiomyocytes. In rabbits, the KATP channel blocker, 5-hydroxydecanoate (5-HD), did not block preconditioning or fostriecin protection. In the pig, 5-HD blocked both preconditioning and fostriecin protection, with return of the rates of ischemic contracture to control. However, 5-HD was an effective blocker of protection only in early ischemia. Fostriecin mimicked preconditioning in the rabbit and the early responses of the preconditioned pig. Preconditioning appears associated with protein phosphorylation in both the rabbit and the pig, but major pathways leading to protection may differ in the two species.

Crevicular fluid analysis around two failing dental implants: a clinical report

The criteria for monitoring tissue health around endosseous implants remain subjective. Disagreement about which clinical measures of peri-implant health are of diagnostic value continues because of the complexity of the disease process and lack of validated measures of peri-implant health. Crevicular fluid analysis of various inflammatory mediators has been investigated as a means of providing objective criteria of tissue health. In this clinical report, the crevicular fluid levels of interleukin-1 beta (IL-1 beta), an inflammatory cytokine, were used to provide an objective measure of the peri-implant health and the effectiveness of treatment for a patient with two failing implants. The measurement of IL-1 beta may be an important supplement to clinical findings in establishing a diagnosis of peri-implantitis.

Involvement of the amino-terminal beta-hairpin of the Aspergillus ribotoxins on the interaction with membranes and nonspecific ribonuclease activity

Ribotoxins are a family of potent cytotoxic proteins from Aspergillus whose members display a high sequence identity (85% for about 150 amino acid residues). The three-dimensional structures of two of these proteins, alpha-sarcin and restrictocin, are known. They interact with phospholipid bilayers, according to their ability to enter cells, and cleave a specific phosphodiester bond in the large subunit of ribosome thus inhibiting protein biosynthesis. Two nonconservative sequence changes between these proteins are located at the amino-terminal beta-hairpin of alpha-sarcin, a characteristic structure that is absent in other nontoxic structurally related microbial RNases. These two residues of alpha-sarcin, Lys 11 and Thr 20, have been substituted with the equivalent amino acids in restrictocin. The single mutants (K11L and T20D) and the corresponding K11L/T20D double mutant have been produced in Escherichia coli and purified to homogeneity. The spectroscopic characterization of the purified proteins reveals that the overall native structure is preserved. The ribonuclease and lipid-perturbing activities of the three mutants and restrictocin have been evaluated and compared with those of alpha-sarcin. These proteins exhibit the same ability to specifically inactivate ribosomes, although they show different activity against nonspecific substrate analogs such as poly(A). The mutant variant K11L and restrictocin display a lower phospholipid-interacting ability correlated with a decreased cytotoxicity. The results obtained are interpreted in terms of the involvement of the amino-terminal beta-hairpin in the interaction with both membranes and polyadenylic acid.

Probing the active site of mitogillin, a fungal ribotoxin

Fungal ribotoxins, such as mitogillin and the related Aspergillus toxins restrictocin and alpha-sarcin, are highly specific ribonucleases, which inactivate the ribosome enzymatically by cleaving the eukaryotic 28S RNA of the large ribosomal subunit at a single phosphodiester bond. The site of cleavage occurs between G4325 and A4326, which are present in a 14-base sequence (the alpha-sarcin loop) conserved among the large subunit rRNAs of all living species. The amino acid residues involved in the cytotoxic activities of mitogillin were investigated by introducing point mutations using hydroxylamine into a recombinant Met-mature mitogillin (mitogillin with a Met codon at the N-terminus and no leader sequence) gene constructed from an Aspergillus fumigatus cDNA clone. These constructs were cloned into a yeast expression vector under the control of the GAL1 promoter and transformed into Saccharomyces cerevisiae. Upon induction of mitogillin expression, surviving transformants revealed that substitutions of certain amino acid residues on mitogillin abolished its cytotoxicity. Non-toxic mutant genes were cloned into an Escherichia coli expression vector, the proteins overexpressed and purified to homogeneity and their activities examined by in vitro ribonucleolytic assays. These studies identified the His-49Tyr, Glu-95Lys, Arg-120Lys and His-136Tyr mutations to have a profound impact on the ribonucleolytic activities of mitogillin. We conclude that these residues are key components of the active site contributing to the catalytic activities of mitogillin.

Discovery of the novel HLA-DRB1*03:77 allele in a Taiwanese unrelated hematopoietic stem cell donor by a sequence-based typing method and identification of the probable HLA haplotype in association with DRB1*03:77

Here, we report a novel human leucocyte antigen (HLA)-DRB1 allele, DRB1*03:77, discovered in a Taiwanese unrelated volunteer hematopoietic stem cell donor by a sequence-based typing (SBT) method. The DNA sequence of DRB1*03:77 is identical to the DNA sequence of DRB1*03:01:01 in exon 2 except one nucleotide at position 223 (G→C). The nucleotide substitution caused an amino acid replacement at residue 46 (E→Q). The formation of DRB1*03:77 was thought as the result of a nucleotide point mutation. The probable HLA-A, HLA-B and HLA-DRB1 haplotype in association with DRB1*03:77 may be deduced as A*33-B*58-DRB1*03:77. The donor was a Minna Taiwanese whose ancestors came from mainland China.

Discovery of the novel HLA-DRB1*16:16 allele in a Taiwanese unrelated bone marrow stem cell donor by a sequence-based typing method and the probable haplotype associated with DRB1*16:16

We report here a de novo HLA-DRB1 allele, DRB1*16:16, discovered in a Taiwanese unrelated volunteer bone marrow stem cell donor by a sequence-based typing (SBT) method. In exon 2, the DNA sequence of DRB1*16:16 is identical to the sequence of DRB1*16:02:01 except the nucleotides at positions 258 (C→T), 260 (C→A) and 261 (T→G). The nucleotide substitution produced an amino acid replacement at residue 58 (A→E). The formation of DRB1*16:16 was probably generated by a DNA sequence recombination event involving DRB1*11:01:01 and DRB1*16:02:01. The probable HLA-A, -B and -DRB1 haplotype in association with DRB1*16:16 may be deduced as A*02-B*38-DRB1*16:16.