Biomedical subjects

John Jacobs

Publications and source records attributed to John Jacobs.

8 recordsLinked to original sources

PubMed2006

CMD: a Cotton Microsatellite Database resource for Gossypium genomics.

BACKGROUND: The Cotton Microsatellite Database (CMD) http://www.cottonssr.org is a curated and integrated web-based relational database providing centralized access to publicly available cotton microsatellites, an invaluable resource for basic and applied research in cotton breeding. DESCRIPTION: At present CMD contains publication, sequence, primer, mapping and homology data for nine major cotton microsatellite projects, collectively representing 5,484 microsatellites. In addition, CMD displays data for three of the microsatellite projects that have been screened against a panel of core germplasm. The standardized panel consists of 12 diverse genotypes including genetic standards, mapping parents, BAC donors, subgenome representatives, unique breeding lines, exotic introgression sources, and contemporary Upland cottons with significant acreage. A suite of online microsatellite data mining tools are accessible at CMD. These include an SSR server which identifies microsatellites, primers, open reading frames, and GC-content of uploaded sequences; BLAST and FASTA servers providing sequence similarity searches against the existing cotton SSR sequences and primers, a CAP3 server to assemble EST sequences into longer transcripts prior to mining for SSRs, and CMap, a viewer for comparing cotton SSR maps. CONCLUSION: The collection of publicly available cotton SSR markers in a centralized, readily accessible and curated web-enabled database provides a more efficient utilization of microsatellite resources and will help accelerate basic and applied research in molecular breeding and genetic mapping in Gossypium spp.

Chromosome Mapping↗

PubMed2006

Benefit of postoperative chemoradiotherapy for patients with unknown primary squamous cell carcinoma of the head and neck.

BACKGROUND: Postopertative adjuvant chemoradiotherapy recently became an established modality for patients with selected high-risk locally advanced head and neck cancers. The optimal treatment of unknown primary squamous cell cancer of the head and neck (SCCHN) continues to be controversial, since major randomized studies excluded those patients. METHODS: We conducted a retrospective review of patients treated during 1995 to 2002 for unknown primary SCCHN. All patients were treated with a neck dissection followed by concurrent high-dose cisplatin (100 mg/m(2)) and bilateral neck radiotherapy. RESULTS: Thirty-seven patients were identified with nodal disease distribution of N1 (5%), N2a (22%), N2b (41%), N2c (8%), N3 (22%), and Nx (3%). Modified neck dissection was done on the majority (30/37 = 81%) of patients. With a median follow-up of 42 months among the survivors, very few patients had regional recurrence (5%) or distant failure (11%), and 89% of patients were alive. The actuarial 5-year overall survival rate could not be estimated because there were no deaths beyond 20 months after surgery. Substantial yet acceptable acute and late morbidities were demonstrated in this cohort of patients. CONCLUSIONS: Postoperative chemoradiotherapy is of potential benefit to patients with unknown primary SCCHN by improving survival and reducing failures. This treatment warrants further prospective evaluation.

Adult↗

PubMed2005

Locoregional IL-2 low dose applications for gastrointestinal tumors.

AIM: To explore the feasibility of local interleukin 2 (IL-2) in patients with different forms of abdominal cancer. This required experimentation with the time interval between IL-2 applications and the methods of application. METHODS: Sixteen patients with stages III and IV of gastrointestinal malignancies (primary or metastatic) who were admitted to our Department of Gastroenterology were treated with locoregionally applied IL-2 in low doses. RESULTS: No major problems applying locoregional IL-2 were encountered. In 6 out of 16 patients, a modest but clinically worthwhile improvement was obtained. Adverse effects were minimal. The therapeutic scheme was well tolerated, even in patients in a poor condition. CONCLUSION: This study demonstrates the feasibility of low dose locoregional IL-2 application in advanced abdominal cancer. Local IL-2 therapy gives only negligible adverse effects. The results suggest that it is important to apply intratumorally. Local IL-2 may be given adjunct to standard therapeutic regimes and does not imply complex surgical interventions. These initial results are encouraging.

Antineoplastic Agents↗

PubMed2005

Occurrence of (+)- and (-)-gossypol in wild species of cotton and in Gossypium hirsutum Var. marie-galante (Watt) Hutchinson.

Gossypol occurs as a mixture of enantiomers in cottonseed. These enantiomers exhibit different biological activities. The (-)-enantiomer is toxic to animals, but it has potential medicinal uses. Therefore, cottonseed with >95% (-)-gossypol could have biopharmaceutical applications. The (+)-enantiomer shows little, if any, toxicity to nonruminant animals. Thus, cottonseed with >95% (+)-gossypol could be more readily utilized as a feed for nonruminants. The (+)- to (-)-gossypol ratio in commercial Upland (Gossypium hirsutum) cottonseed is usually about 3:2, whereas that in commercial Pima cottonseed (Gossypium barbadense) is approximately 2:3. Herein are reported the (+)- to (-)-gossypol ratios in the seed from 28 wild species of cotton (194 accessions), 94 accessions of G. hirsutum var. marie-galante, and 3 domesticated species (11 accessions). It was found that some or all of the accessions of Gossypium darwinii, Gossypium sturtianum, Gossypium areysianum, Gossypium longicalyx, Gossypium harknessii, and Gossypium costulatum produce an excess of (-)-gossypol but none >65%. At least one accession of Gossypium anomalum, Gossypium mustelinum, Gossypium gossypioides, and Gossypium capitis-viridis contained >94% (+)-gossypol. One of the 94 accessions of G. hirsutum var. marie-galante (i.e., no. 2469) contained 97% (+)-gossypol.

Animal Feed↗

PubMed2004

The preferred route for the degradation of silencing target RNAs in transgenic plants depends on pre-established silencing conditions.

RNA silencing can be initiated upon dsRNA accumulation and results in homology-dependent degradation of target RNAs mediated by 21-23 nt small interfering RNAs (siRNAs). These small regulatory RNAs can direct RNA degradation via different routes such as the RdRP/Dicer- and the RNA-induced silencing complex (RISC)-catalysed pathways. The relative contribution of both pathways to degradation of target RNAs is not understood. To gain further insight in the process of target selection and degradation, we analysed production of siRNAs characteristic for Dicer-mediated RNA degradation during silencing of mRNAs and chimeric viral RNAs in protoplasts from plants of a transgenic tobacco silencing model line. We show that small RNA accumulation is limited to silencing target regions during steady-state mRNA silencing. For chimeric viral RNAs, siRNA production appears dependent on pre-established cellular silencing conditions. The observed siRNA accumulation profiles imply that silencing of viral target RNAs in pre-silenced protoplasts occurs mainly via a RISC-mediated pathway, guided by (pre-existing) siRNAs derived from cellular mRNAs. In cells that are not silenced at the time of infection, viral RNA degradation seems to involve Dicer action directly on the viral RNAs. This suggests that the silencing mechanism flexibly deploys different components of the RNA degradation machinery in function of the prevailing silencing status.

Cell Line↗

PubMed2004

Postoperative concurrent radiotherapy and chemotherapy for high-risk squamous-cell carcinoma of the head and neck.

BACKGROUND: Despite the use of resection and postoperative radiotherapy, high-risk squamous-cell carcinoma of the head and neck frequently recurs in the original tumor bed. We tested the hypothesis that concurrent postoperative administration of cisplatin and radiotherapy would improve the rate of local and regional control. METHODS: Between September 9, 1995, and April 28, 2000, 459 patients were enrolled. After undergoing total resection of all visible and palpable disease, 231 patients were randomly assigned to receive radiotherapy alone (60 to 66 Gy in 30 to 33 fractions over a period of 6 to 6.6 weeks) and 228 patients to receive the identical treatment plus concurrent cisplatin (100 mg per square meter of body-surface area intravenously on days 1, 22, and 43). RESULTS: After a median follow-up of 45.9 months, the rate of local and regional control was significantly higher in the combined-therapy group than in the group given radiotherapy alone (hazard ratio for local or regional recurrence, 0.61; 95 percent confidence interval, 0.41 to 0.91; P=0.01). The estimated two-year rate of local and regional control was 82 percent in the combined-therapy group, as compared with 72 percent in the radiotherapy group. Disease-free survival was significantly longer in the combined-therapy group than in the radiotherapy group (hazard ratio for disease or death, 0.78; 95 percent confidence interval, 0.61 to 0.99; P=0.04), but overall survival was not (hazard ratio for death, 0.84; 95 percent confidence interval, 0.65 to 1.09; P=0.19). The incidence of acute adverse effects of grade 3 or greater was 34 percent in the radiotherapy group and 77 percent in the combined-therapy group (P<0.001). Four patients who received combined therapy died as a direct result of the treatment. CONCLUSIONS: Among high-risk patients with resected head and neck cancer, concurrent postoperative chemotherapy and radiotherapy significantly improve the rates of local and regional control and disease-free survival. However, the combined treatment is associated with a substantial increase in adverse effects.

Adolescent↗

PubMed2002

An active role for endogenous beta-1,3-glucanase genes in transgene-mediated co-suppression in tobacco.

Post-transcriptional gene silencing (PTGS) is characterized by the accumulation of short interfering RNAs that are proposed to mediate sequence-specific degradation of cognate and secondary target mRNAs. In plants, it is unclear to what extent endogenous genes contribute to this process. Here, we address the role of the endogenous target genes in transgene-mediated PTGS of beta-1,3-glucanases in tobacco. We found that mRNA sequences of the endogenous glucanase glb gene with varying degrees of homology to the Nicotiana plumbaginifolia gn1 transgene are targeted by the silencing machinery, although less efficiently than corresponding transgene regions. Importantly, we show that endogene-specific nucleotides in the glb sequence provide specificity to the silencing process. Consistent with this finding, small sense and antisense 21- to 23-nucleotide RNAs homologous to the endogenous glb gene were detected. Combined, these data demonstrate that a co-suppressed endogenous glucan ase gene is involved in signal amplification and selection of homologous targets, and show that endogenous genes can actively participate in PTGS in plants. The findings are introduced as a further sophistication of the post-transciptional silencing model.

Base Sequence↗

PubMed2002

Penetrating trauma to the head and neck from a nail gun: a unique mechanism of injury.

Published reports of nail gun injuries to the head and neck are rare. We describe the cases of three patients who sustained nail gun injuries to the head and who were managed at our institution. All patients were treated successfully and all recovered with minimal morbidity. Any physician who is called on to manage a nail gun injury to the head or neck should understand that most likely the patient will have sustained a surprisingly limited amount of tissue injury, owing to the relatively low velocity of the projectile compared with that delivered by firearms. Computed tomography and selective angiography can play a vital role in assessing the integrity of relevant vascular structures. Moreover, catheter angiography with embolization can be a most useful nonsurgical adjunct to control the extent of vascular injury.

Adolescent↗