Biomedical subjects

H Nelson

Publications and source records attributed to H Nelson.

At least 55 records · Page 3Linked to original sources

PubMed1999

Induction of antitumor immunity after cure of pulmonary metastases, using staphylococcal enterotoxin B and bispecific antibody.

The combination of staphylococcal enterotoxin B (SEB) and anti-p97 x anti-CD3 bispecific antibody (bsAb) cures 60%-80% of mice with established pulmonary metastases of the syngeneic p97+ murine melanoma, CL62. We investigated the ability of cured mice to generate protective antitumor immunity. In tumor rechallenge experiments, CL62-cured mice developed protective immunity against rechallenge with CL62. The majority of mice also rejected the p97-negative parental cell line, K1735, indicating an immune response to tumor antigens common to both cell lines that were not bsAb-targeted. A significant humoral response developed against p97 antigen, but not against other antigens common to both CL62 and K1735. That the majority of cured mice nevertheless rejected K1735 suggests that tumor immunity is not antibody-dependent. Evidence of cellular immunity was obtained from the results of delayed-type hypersensitivity, proliferation and cytotoxicity assays, which revealed the presence of tumor-specific memory in bsAb-treated, CL62-cured mice. CD8+ T cells from cured, but not control mice were able to lyse tumor; however, memory CD4 cells had no cytolytic function. In vivo, however, both CD4 and CD8 T cells were required for effective protective immunity. These studies demonstrate that treatment with SEB and bsAb not only confers passive immune effects of tumor eradication, but also actively promotes the generation of a host antitumor immune response.

Animals↗

PubMed1999

Comparison of inhaled salmeterol and oral zafirlukast in patients with asthma.

BACKGROUND: Salmeterol, a long-acting beta2 -agonist, and zafirlukast, a leukotriene receptor antagonist, are both indicated for the treatment of asthma in adolescent and adult patients. OBJECTIVE: We sought to compare the effect of 4 weeks of treatment with inhaled salmeterol xinafoate versus oral zafirlukast in the treatment of persistent asthma. METHODS: This was a randomized, double-blind, double-dummy, parallel-group, multicenter clinical trial. Patients, over 80% of whom were on a concurrent inhaled corticosteroid regimen, were treated for 4 weeks with either inhaled salmeterol xinafoate 42 microgram twice daily administered by means of a metered-dose inhaler or oral zafirlukast 20 mg twice daily. The primary efficacy measure was morning peak expiratory flow (PEF); secondary efficacy measures included evening PEF, asthma symptom scores, supplemental albuterol use, nighttime awakenings, sleep symptoms, asthma exacerbations, and FEV1. RESULTS: Both inhaled salmeterol and oral zafirlukast resulted in within-group improvements from baseline in measures of pulmonary function, asthma symptoms, and supplemental albuterol use. Salmeterol treatment resulted in significantly greater improvements from baseline compared with zafirlukast for most efficacy measurements, including morning PEF (29.6 vs 13.0 L/min; P </= .001), percentage of symptom-free days (22.4% vs 8.8%; P </= .001), and percentage of days and nights with no supplemental albuterol use (30.5% vs 11.3%; P </= .001). There were no differences in safety profiles as assessed by adverse event monitoring. CONCLUSION: In patients with persistent asthma, most of whom were concurrently using inhaled corticosteroids, treatment with inhaled salmeterol provided significantly greater improvement than oral zafirlukast in overall asthma control over the 4-week treatment period.

Administration, Inhalation↗

PubMed1999

Dose-ranging study of a new steroid for asthma: mometasone furoate dry powder inhaler.

A new formulation of mometasone furoate (MF) for administration by dry powder inhaler (DPI) was evaluated for the treatment of asthma. A 12-week, double-blind, placebo-controlled dose-ranging study compared the efficacy and safety of three doses of MF DPI (100, 200 and 400 mcg b.i.d) with beclomethasone dipropionate (BDP) 168 mcg b.i.d. administered by metered dose inhaler in 365 adult or adolescent patients being treated with inhaled glucocorticoids. The mean change from baseline to endpoint (last treatment visit) for forced expiratory volume in 1 sec (FEV1) was the primary efficacy variable. Secondary efficacy variables included other objective measures of pulmonary function [forced vital capacity (FVC), forced expiratory flow 25-75% (FEV25-75%.) and peak expiratory flow rate (PEFR)] as well as subjective measures of therapeutic response (patients' daily evaluation of asthma symptoms and physicians' evaluation). At endpoint, all four active treatments were significantly more effective than placebo (P < 0.01) in improving FEV1 (MF DPI 5 to 7%, BDP 3%, placebo -6.6%) and all other measures of pulmonary function (FVC: MF DPI 4 to 5%, BDP 2%, placebo -4.7%; FEF25-75%: MF DPI 6 to 18%, BDP 7.5%, placebo -9.5%; PEFR (AM): MF DPI 5 to 10%, BDP 5.7%, placebo -7%). A consistent trend was observed for better improvement in patients treated with MF DPI 200 mcg b.i.d. than with MF DPI 100 mcg b.i.d., with no apparent additional benefit of MF DPI 400 mcg b.i.d. Results for the MF DPI 100 mcg b.i.d. and BDP 168 mcg b.i.d. treatment groups were similar. Patients' and physicians' subjective evaluations of symptoms found similar improvement in the MF DPI 200 and 400 mcg b.i.d. treatment groups, which were slightly better than that in the MF DPI 100 mcg b.i.d. group. Symptoms tended to worsen in the placebo group. MF DPI was well tolerated at all dose levels and the most frequently reported treatment-related adverse effects were headache, pharyngitis and oral candidiasis. No evidence of HPA-axis suppression was detected in any treatment group. In summary, all doses of MF DPI were well tolerated and significantly improved lung function and MF DPI 400 mcg (200 mcg b.i.d.) was the optimal dose in this study of patients with moderate persistent asthma.

Adolescent↗

PubMed1999

Primary myocutaneous flap closure following resection of locally advanced pelvic malignancies.

BACKGROUND: Perineal wounds, created at the time of extended resection for locally advanced malignancy and following chemoradiation, are at risk of serious complications. METHODS: To determine whether immediate myocutaneous flap closure prevents complications, 57 patients treated with multimodality therapy and proctectomy (35 perineal wounds) or sacrectomy (22 posterior wounds) were studied. Patients were categorized according to whether they underwent primary skin and pelvic closure (group 1; ,n = 20); primary skin and omental pelvic closure (group 2; n = 24); or immediate myocutaneous flap closure (group 3; n = 13). RESULTS: Groups were similar with respect to age and sex; however, group 1 had more primary tumours and required less radical surgery and chemoirradiation than groups 2 and 3. Groups 1 and 2 experienced more complications overall (eight of 20, nine of 24 and three of 13 patients in groups 1, 2 and 3 respectively), more acute wound complications (seven of 20, nine of 24 and two of 13), delayed wound healing (three of 20, six of 24 and one of 13) and more reoperations for perineal wound problems (five of 20, seven of 24 and zero of 13). Patients in group 2 had a significantly longer hospital stay than those in group 1. Flap closure (group 3) did not increase the length of stay. The routine use of primary flap closure reduced overall wound complications (eight of 31 versus ten of 26 patients) and length of hospitalization (13 versus 17 days). CONCLUSION: Complete wound healing was achieved in all patients; however, immediate myocutaneous flap closure reduced the need for readmission and reoperation.

Female↗

PubMed1999

Rapid transbilayer movement of fluorescent phospholipid analogues in the plasma membrane of endocytosis-deficient yeast cells does not require the Drs2 protein.

Evidence is presented that endocytosis-deficient Saccharomyces cerevisiae end4 yeast cells rapidly internalize the fluorescent phospholipid analogues 1-palmitoyl-2-{6-[7-nitro-2,1, 3-benzoxadiazol-4-yl(NBD)amino] caproyl}phosphatidylcholine (P-C6-NBD-PtdCho) and P-C6-NBD-phosphatidylserine (P-C6-NBD-PtdSer). Both analogues redistributed between the exoplasmic and cytoplasmic leaflet with a half-time of < 15 min at 0 degrees C. The plateau of internalized analogues was about 70%. Transbilayer movement is probably protein-mediated, as the flip-flop of both analogues was very slow in liposomes composed of plasma-membrane lipids. Rapid analogue internalization was not abolished on depletion of intracellular ATP by about 90%. For P-C6-NBD-PtdCho only was a moderate decrease in the plateau of internalized analogues of about 20% observed, while that of P-C6-NBD-PtdSer was not affected. The Drs2 protein plays only a minor role, if any, in the rapid transbilayer movement of analogues in S. cerevisiae end4 cells. In S. cerevisiae end4 Deltadrs2 cells harbouring both an end4 allele and a drs2 null allele, about 60% and 50% of P-C6-NBD-PtdCho and P-C6-NBD-PtdSer, respectively, became internalized within 15 min at 0 degrees C. The preferential orientation of P-C6-NBD-PtdSer to the cytoplasmic leaflet is in qualitative agreement with the sequestering of endogenous phosphatidylserine to the cytoplasmic leaflet, as assessed by binding of annexin V. Virtually no binding of annexin V to spheroplasts of the parent wild-type strain or the mutant strains was observed. Likewise, no difference in the exposure of endogenous aminophospholipids to the exoplasmic leaflet between these strains was found by labelling with trinitrobenzenesulfonic acid. Thus, lipid asymmetry, at least of aminophospholipids, was preserved in S. cerevisiae end4 cells independently of the presence of the Drs2 protein.

4-Chloro-7-nitrobenzofurazan↗

PubMed1999

Mendelian diseases among Roman Jews: implications for the origins of disease alleles.

The Roman Jewish community has been historically continuous in Rome since pre-Christian times and may have been progenitor to the Ashkenazi Jewish community. Despite a history of endogamy over the past 2000 yr, the historical record suggests that there was admixture with Ashkenazi and Sephardic Jews during the Middle Ages. To determine whether Roman and Ashkenazi Jews shared common signature mutations, we tested a group of 107 Roman Jews, representing 176 haploid sets of chromosomes. No mutations were found for Bloom syndrome, BRCA1, BRCA2, Canavan disease, Fanconi anemia complementation group C, or Tay-Sachs disease. Two unrelated individuals were positive for the 3849 + 10C->T cystic fibrosis mutation; one carried the N370S Gaucher disease mutation, and one carried the connexin 26 167delT mutation. Each of these was shown to be associated with the same haplotype of tightly linked microsatellite markers as that found among Ashkenazi Jews. In addition, 14 individuals had mutations in the familial Mediterranean fever gene and three unrelated individuals carried the factor XI type III mutation previously observed exclusively among Ashkenazi Jews. These findings suggest that the Gaucher, connexin 26, and familial Mediterranean fever mutations are over 2000 yr old, that the cystic fibrosis 3849 + 10kb C->T and factor XI type III mutations had a common origin in Ashkenazi and Roman Jews, and that other mutations prevalent among Ashkenazi Jews are of more recent origin.

Alleles↗

PubMed1999

Comparative efficacy and safety of albuterol sulfate Spiros inhaler and albuterol metered-dose inhaler in asthma.

STUDY OBJECTIVE: To compare the long-term efficacy and safety of albuterol administration using a Spiros Inhalation System (Dura Pharmaceuticals; San Diego, CA) dry powder inhaler (DPI) and albuterol (Ventolin; Glaxo Wellcome; Research Triangle Park, NC) administration using a metered-dose inhaler (MDI) in patients with asthma. MATERIALS AND METHODS: This was a phase III, 12-week, randomized, double-blind, double-dummy, placebo-controlled, parallel-group, multicenter study of 283 adolescent and adult patients with mild to moderate asthma. The patients were randomized into one of three treatment groups: the Spiros group, who were given 108 microg/actuation of albuterol sulfate equivalent to 90 microg of albuterol base; the MDI group, who were given 90 microg/actuation of albuterol; and the placebo group. RESULTS: Over the length of the study, the Spiros and MDI groups were comparable in all FEV1 parameters. Both active treatment groups were superior to the placebo group for each FEV1 parameter at all visits. With the exception of differences at treatment week 0 for the maximum percent change in the FEV1, the duration of effect, and the area under the curve at baseline, there were no statistically significant differences between the Spiros and MDI groups for any FEV1 parameters. Using a repeated-measures analysis, the FEV1 parameters at week 0 for the Spiros group were not statistically significantly different from the parameters at weeks 4, 8, and 12. The same analysis effect at week 0 for the MDI group was greater for maximum percent change in the FEV1 from baseline (weeks 4, 8, and 12) and duration of effect. Adverse events and changes in clinical laboratory values, vital signs, ECG results, and physical examinations were reported with similar incidence in each of the three treatment groups. CONCLUSION: Both active treatments were superior to the placebo treatment. The Spiros DPI was well tolerated and was as effective as the albuterol MDI in treating patients with moderate asthma.

Administration, Inhalation↗

PubMed1998

Laparoscopic colectomy for colon cancer: trial update.

Laparoscopic colon surgery is gaining acceptance for benign conditions, but cannot yet be considered an established procedure for malignancy. The main reported benefit of the technique is the reduction in length of hospital stay. Other potential benefits such as cosmesis, improvement in quality of life, physiologic and immunologic advantages, as well as reduced complication rates have not been clearly demonstrated. Concerns about laparoscopic colon surgery for cancer including the possibility of inadequate resection, tumor staging, and altered tumor spread due to pneumoperitoneum have only been partially addressed by retrospective and experimental studies and require a prospective randomized trial for definitive resolution. Details of the trial currently underway sponsored by the National Institutes of Health are described. Although innovations in clinical practice and increased familiarity account for the expanding popularity of laparoscopic colon surgery, results from this and similar worldwide trials are needed before this approach can be recommended for cancer.

Animals↗

PubMed1998

Ileal pouch-anal anastomosis in patients with colorectal cancer: long-term functional and oncologic outcomes.

UNLABELLED: When colorectal cancer complicates chronic ulcerative colitis or familial adenomatous polyposis, the role of ileal pouch-anal anastomosis is uncertain because of concerns that the procedure may compromise oncologic therapy and that oncologic therapy may compromise ileal pouch-anal anastomosis function. AIM: This study was undertaken to investigate the impact both of ileal pouch-anal anastomosis on cancer outcomes and of cancer treatments on ileal pouch-anal anastomosis function. PATIENTS AND METHODS: Of 1,616 patients undergoing ileal pouch-anal anastomosis for chronic ulcerative colitis or familial adenomatous polyposis (1981-1994), 77 patients were identified with adenocarcinoma of the colon (56), rectum (17), or both (4). Data were obtained from an ileal pouch-anal anastomosis registry, case notes, and postal and telephone surveys. RESULTS: Mean age of the 77 index patients was 37 (range, 13-60) years. Stage distribution was as follows: Stage 0, 9; Stage I, 31; Stage II, 15; Stage III, 22 patients. Twelve patients died with systemic disease (6 with a local component) after a mean follow-up of 6 (range, 2-15) years. Twenty-two patients received adjuvant therapy (chemotherapy, 16; radiotherapy, 2; both, 4 patients). Chemotherapy complications requiring dose reduction or interruption occurred in three (15 percent) patients. One patient developed radiation enteritis (17 percent). Pouch failure occurred in 16 percent of cancer patients, compared with 7 percent for the overall registry. There were no differences between cancer and non-cancer groups in operative complications, median stool frequency, incontinence, pad usage, or pouchitis. CONCLUSIONS: Although pouch failure is more common, ileal pouch-anal anastomosis can be performed in the setting of colorectal cancer without significant impact on oncologic outcome or long-term ileal pouch-anal anastomosis function.

Adenocarcinoma↗

PubMed1998

Diagnostic and therapeutic applications of monoclonal antibodies in colorectal cancer.

PURPOSE: The study contained herein was undertaken to review and summarize the current literature on diagnostic and therapeutic applications of monoclonal antibodies in colorectal cancer. RESULTS: Limitations of traditional imaging techniques have encouraged development of targeted imaging strategies using radiolabeled monoclonal antibodies. Diagnostic immunoscintigraphy can detect lesions not identified by conventional imaging modalities, although it has not proven useful in the management of primary colorectal cancers and in hepatic metastases. Immunoscintigraphy shows promise in cases of local recurrence and rising carcinoembryonic antigen values; however, the impact of immunoscintigraphy on clinical outcomes and cost-effectiveness remains unproven. Radioimmunoguided surgery has been advocated as a method of more accurately detecting tumor extension and accomplishing radical resection. The technique remains controversial, and its use is not widespread. With respect to therapeutic applications, immunotherapy has most often been investigated in the setting of advanced stage disease. Results in this setting have been poor. In contrast, adjuvant immunotherapy after resection of Dukes C carcinoma has achieved convincing results, with improvements in survival comparable with that of adjuvant chemotherapy. Adjuvant trials are now under way to examine the effectiveness of monoclonal antibodies in the postoperative treatment of early-stage (II) tumors and the combination of monoclonal antibodies and chemotherapy in advanced-stage (III) tumors. Bispecific antibodies, or immunoconjugates with cytokines or toxins, represent additional areas of interest and future investigations. CONCLUSIONS: At present, immunoscintigraphy is not sufficient to determine, by itself, resectability of colorectal tumor and has limited usefulness in select cases of recurrent cancer and possibly in cases of rising carcinoembryonic antigen values. Immunotherapy with monoclonal antibodies as a postoperative adjuvant treatment shows promise and is currently being investigated in national trials.

Animals↗

PubMed1998

Management of acquired rectourinary fistulas: outcome according to cause.

PURPOSE: Acquired rectourinary fistulas, an infrequent complication of pelvic conditions, remain a therapeutic problem for which neither a widely accepted classification nor long-term outcome data are available. This study was designed to provide a new etiologic classification system and examine the success of various surgical therapies. It also looked at the need for permanent fecal or urinary diversion or radical excision depending on the cause of the fistula, i.e., benign vs. malignancy-related. METHODS: A retrospective analysis was made of 41 patients treated for acquired rectourinary fistulas between 1980 and 1995. Acquired rectourinary fistulas were classified as 1) benign but caused by Crohn's disease, trauma, perirectal sepsis, or iatrogenic injury; and 2) malignancy-related fistulas secondary to neoplasm, radiation, surgery, or combined tumor and treatment effects. Surgical interventions were classified as repair, excision, fecal diversion, and urinary diversion. RESULTS: Thirty-seven males and 4 females with acquired rectourinary fistula were identified with a mean age of 62 (range, 28-90) years. Nineteen patients had fistulas involving their urethras, and 22 patients had fistulas involving the bladder. Eight patients were not treated surgically; one was not treated because of an advanced malignancy, three because of patient preference, three because of sepsis, and one because of a poor general condition. Of the remaining 33 patients, nine had benign fistulas of which two were the result of Crohn's disease, two were the result of trauma, two were from an iatrogenic response, and three were from perirectal sepsis. Twenty-four patients had malignancy-related fistulas, and five patients had neoplasm at their fistula sites. The remaining 19 patients had malignancy-related fistulas that were the result of cancer treatments. Of the 19 malignancy-related fistulas, 5 were from radiation, 9 were from surgical trauma, and 5 were from radiation and surgical trauma. Forty-nine percent of the patients had undergone attempts at fistula treatment before referral. A resolution of symptoms after initial and reoperative surgery occurred more often in patients with benign fistulas (44 and 100 percent; mean, 1.8 surgeries per patient) compared with malignancy-related fistulas (21 and 88 percent; mean, 2.1 surgeries per patient). The rates of permanent fecal, urinary, and fecal plus urinary diversion were also lower for benign fistulas (11, 0, and 33 percent) compared with malignancy-related fistulas (13, 8, and 54 percent). Permanent diversion was avoided in 56 percent of the benign fistulas but in only 25 percent of the malignancy-related fistulas. The rates of excisional and radical (ileal conduit) surgery were lower for benign fistulas than for malignancy-related fistulas (44 and 11 percent vs. 50 and 54 percent). CONCLUSION: Successful management of rectourinary fistulas typically requires aggressive reoperative therapy with permanent diversion more often required for malignancy-related fistulas. Better outcomes can be anticipated for benign fistulas.

Adult↗

PubMed1998

Utility of C57BL/6J x 129/SvJae embryonic stem cells for generating chromosomal deletions: tolerance to gamma radiation and microsatellite polymorphism.

We have previously reported a method for making nested deletion complexes in mice by irradiation of ES cells. The key to this technology is that F1 hybrid ES cells (called v17.2) of the genotype (BALB/cTa x 129/SvJae) retain germline colonizing ability after exposure to levels of ionizing radiation that induce chromosomal deletions. In an effort to identify other genotypes of ES cells that are suitable for this technology, the radiation sensitivity of the cell line v6.4, which is of the genotype (C57BL/6J x 129/SvJae), was investigated. After treatment with a range of radiation exposures, the developmental potential of these cells was assayed by injecting them into blastocysts to generate chimeric mice. These experiments showed that while cell lethality increased as the level of radiation increased, the surviving ES cells retained full totipotency at all exposure levels, up to 400 Rads. Because polymorphism between parental microsatellite alleles in the F1 hybrid ES cells is important for ascertaining the sizes of induced deletions, the 129/SvJ and 129/SvJae allele sizes of 48 microsatellite loci on chromosome (Chr) 17 were determined. This revealed a higher level of polymorphism between 129 and C57BL/6J on Chr 17. The radiation tolerance, high polymorphism between parental strains, and presence of the widely used C57BL/6J strain component make v6.4 ES cells an attractive cell line for generating radiation-induced chromosomal deletions.

Animals↗

PubMed1998

Accuracy of computed tomography in determining resectability for locally advanced primary or recurrent colorectal cancers.

AIM: To determine the accuracy of computed axial tomography (CT) in determining tumor resectability in patients with locally advanced primary (T4) or locally recurrent colorectal cancer. METHODS: Computed tomography scans of 84 patients with "resectable" locally advanced primary rectal cancer (n = 12) or recurrent colorectal cancer (n = 72) were compared with the operative findings to assess the accuracy of abdominal and pelvic CT in determining extent of disease and resectability. RESULTS: At surgery, disease was confined to the pelvis in 63 patients, the abdomen in 7, and involved both the pelvis and abdomen in 14. Computed tomography correctly identified these anatomic sites of tumor in 87% of patients, with 89% and 80% accuracies for pelvic and abdominal disease, respectively. Tumor resection was performed in 71 patients (85%), but was not in 13 patients because of locally unresectable disease in 8 and metastatic disease in 5. The accuracy of predicting tumor-related operability was 85%. With regard to adjacent organ resection, CT was accurate in determining the need for sacrectomy or hysterectomy, but overestimated the need for urinary organ resection. Based on histological examination of resection margins, CT correctly staged (n = 45) or overstaged (n = 9) 54 patients (64%) and understaged the remaining 30. The ability of CT to preoperatively predict a locally advanced tumor after preoperative radiation therapy as not being fixed was 30%, fixed but resectable 75%, and fixed but not resectable 25%. CONCLUSIONS: Computed tomography is generally reliable at identifying disease as being confined to one region, and for predicting the need for adjacent organ resection. It is less discriminating for predicting local tumor resectability.

Adult↗

PubMed1998

Metal ions suppress the abnormal taste behavior of the Drosophila mutant malvolio.

A mutation in the malvolio (mvl) gene affects taste behavior in Drosophila melanogaster. The malvolio gene encodes a protein (MVL) that exhibits homology to the mammalian natural resistance-associated macrophage proteins. It is also homologous to the Smf1 protein from Saccharomyces cerevisiae, which we have recently demonstrated to function as a Mn2+/Zn2+ transporter. We proposed that the Drosophila and mammalian proteins, like the yeast SMF1 gene product, are metal-ion transporters. To test this hypothesis, malvolio mutant flies were allowed to develop, from egg to adulthood, on a medium containing elevated concentrations of metal ions. Mutant flies that were reared in the presence of 10 mmol l-1 MnCl2 or FeCl2 developed into adults with recovered taste behavior. CaCl2 or MgCl2 had no effect on the mutant's taste perception. ZnCl2 inhibited the effect of MnCl2 when both ions were supplied together. Similar suppression of the abnormal taste behavior was observed when mvl mutants were fed MnCl2 or FeCl2 only at the adult stage. Furthermore, exposure of adult mutant flies to these ions in the testing plate for only 2 h was sufficient to restore normal taste behavior. The suppression of the defective taste behavior suggests that MVL functions as a Mn2+/Fe2+ transporter and that Mn2+ and/or Fe2+ are involved in the signal transduction of taste perception in Drosophila adults.

Animals↗

PubMed1998

Organellar H(+)-ATPase--site directed mutagenesis and suppressor mutants.

The oligomeric state of the proteolipid subunit of V-ATPase from Saccharomyces cerevisiae was studied using hemagglutinine (HA) epitope-tag. Like with several other highly hydrophobic proteins, the proteolipid tends to aggregate in the presence of sodium dodecyl sulfate (SDS). We observed that the oligomeric state of the proteolipid predetermined its tendency for aggregation. Recently we discovered a novel V-ATPase subunit, denoted as M16 for the mammalian enzyme and Vma10p for the yeast enzyme, that is homologous to the b subunit of the membrane sector of F-ATPases. It is assumed that the structure of Vma10p resembles that of subunit b which is basically two anti parallel helices. We mutated the VMA10 gene to change charges on the protein in helices and to introduce helix braking instead of helix forming amino acids. The functionality of the mutated VMA10 was analyzed by growing the transformed yeast cells on a YPD medium buffered at pH 7.5. Two inactive site-directed mutants we used for obtaining second-site suppressors. Mutagenesis with EMS was utilized to get an equal chance of obtaining intra and extragene second-site suppressors. To our surprise the number of colonies that grew at pH 7.5 was too large to account for mutations in V-ATPase subunits. Apparently, mutations that are situated in genes that do not encode V-ATPase subunits could reverse the phenotype of V-ATPase null mutations resulting in growth at pH 7.5. The large number of colonies that grew at pH 7.5 after EMS treatment suggest a big complex with multiple subunits as a target for mutagenesis. The observed phenomenon is very intriguing. If the responsible protein complex is identified, it may shed light on an important and novel cell biology subject.

Amino Acid Sequence↗

PubMed1998

[Rectal carcinomas in HNPCC].

The true incidence of rectal cancer in HNPCC is still unknown. In our retrospective series analyzing 42 probands from HNPCC families, we found rectal cancer primaries in 29% of our probands. Patients with a first cancer diagnosed in the rectum developed metachronous colon cancer in 54% of the cases. These numbers indicate a requirement to discuss the most appropriate surgical procedure for preventive intervention (ileorectal anastomosis versus ileoanal pouch procedure).

Adult↗

PubMed1997

Locally advanced primary colorectal cancer: intraoperative electron and external beam irradiation +/- 5-FU.

PURPOSE: For locally advanced primary colorectal cancer, our institution has combined intraoperative electron irradiation (IOERT) with external beam irradiation (EBRT) +/- 5-fluorouracil (5-FU) and surgical resection. Disease control and survival were compared with the current IOERT and prior non-IOERT regimens. METHODS AND MATERIALS: From April 1981 through August 1995, 61 patients received an IOERT dose of 10-20 Gy, usually combined with 45-55 Gy of fractionated EBRT; 56 had minimum follow-up of 18 months. The amount of residual disease remaining at IOERT after exploration and maximal resection in the 56 patients was gross in 16, < or = microscopic in 39, and unresected in 1. RESULTS: Survival (SR) and disease control were analyzed as a function of potential prognostic factors. Factors that achieved statistical significance for improved overall survival included treatment sequence of preop EBRT + 5-FU (vs. postoperative EBRT + 5-FU, p = 0.003) and < or = microscopic residual disease after maximal resection (vs. gross residual, p = 0.005). Those that appeared to favorably impact disease-free survival included EBRT + 5-FU (vs. EBRT alone, p = 0.01), < or = microscopic residual (vs. gross, p = 0.0014), and colon site of primary (vs. rectum, p = 0.009). Failures within an irradiation field have occurred in 4 of 16 patients (25%) who presented with gross residual after partial resection vs. 2 of 39 (5%) with < or = microscopic residual after gross total resection (p = 0.01). The significant prognostic factors for a decrease in distant metastases were the same as for disease-free SR with respective p-values of 0.013 (EBRT + 5-FU), 0.008 (microscopic residual), and 0.03 (colon primary). The current data suggests a relationship between IOERT dose and incidence of Grade 2 or 3 neuropathy (< or = 12.5 Gy--1 of 29 or 3%, > or = 15 Gy--6 of 26 or 23%, p = 0.03). CONCLUSIONS: Both overall survival and disease control appear to be improved with the addition of IOERT to standard treatment. More routine use of systemic therapy is indicated as a component of IOERT containing treatment regimens because the incidence of distant metastases was 50% of patients at risk.

Adult↗

PubMed1997

The treatment of locally advanced colon cancer.

PURPOSE: The results of therapy for 103 patients with locally advanced colon cancer who received radiotherapy were analyzed to determine the outcome and tolerance of therapy. METHODS AND MATERIALS: Between 1974 and 1994, 103 patients received radiotherapy and maximal resection of locally advanced colon cancers. Following resection, 50 patients had no residual disease, 18 patients had microscopic residual disease, and 35 patients had gross residual disease. External beam radiotherapy was initiated 1 to 4 months following resection except in two patients who received preoperative radiotherapy. Treatment was delivered to the tumor bed and adjacent lymph nodes using 4 to 18 MV X-rays with doses ranging from 16.2 to 60 Gy. Intraoperative electron radiotherapy (IOERT) was also administered to 11 of the patients with doses ranging from 10 to 20 Gy. Chemotherapy was administered to 77 patients. Follow-up in survivors ranged from 0.5 to 17 years (median: 5.8 years). RESULTS: The 5-year actuarial local failure rate was 10% for patients with no residual disease, 54% for patients with microscopic residual disease, and 79% for patients with gross residual disease (p < 0.0001). For patients with residual disease, local failure occurred in 11% of patients receiving IOERT compared with 82% of patients receiving only external beam therapy (p = 0.02). The 5-year actuarial survival rate was 66% for patients with no residual disease, 47% for patients with microscopic residual disease, and 23% for patients with gross residual disease (p = 0.0009). The 5-year survival rate in patients with residual disease was 76% for patients receiving IOERT and 26% for patients receiving external beam therapy alone (p = 0.04). CONCLUSIONS: Patients with locally advanced colon cancer who have had a complete resection have a high probability of local control after external beam irradiation +/- 5 fluorouracil (5FU)-based systemic therapy. The toxicity of therapy can be minimized with attention to treatment technique and dose. Local control and survival rates in patients with residual disease who received IOERT appear to be significantly greater than for those patients who received external beam radiotherapy therapy alone.

Adult↗