Microcolinearity in sh2-homologous regions of the maize, rice, and sorghum genomes

Large regions of genomic colinearity have been demonstrated among grass species by recombinational mapping, but the degree of chromosomal conservation at the sub-centimorgan level has not been extensively investigated. We cloned the rice and sorghum genes homologous to the sh2 locus of maize on bacterial artificial chromosomes (BACs), and observed that a homologue of the maize a1 gene was also present on each of these BACs. In sorghum, we found a direct duplication of a1 homologues separated by about 10 kb. In maize, sh2 and a1 are approximately 140 kb apart and transcribed in the same direction, with sh2 upstream of a1. In rice and sorghum, this arrangement is fully conserved. However, the sh2 and a1 homologues are separated by about 19 kb in both rice and sorghum. We found low-copy-number and repetitive DNAs between the sh2 and a1 homologues of sorghum and rice. The sh2 and a1 homologues cross-hybridized, but the repetitive DNA and most low-copy-number sequences between these genes did not. These results indicate that maize, sorghum, and rice have conserved gene order and composition in the sh2-a1 region, but have acquired extensive qualitative and quantitative differences in the sequences between these genes.     

A novel role for murine IL-4 in vivo: induction of MUC5AC gene expression and mucin hypersecretion

Mucus hypersecretion and plugging of lower respiratory tract airways contributes to the morbidity and mortality associated with asthma. Interleukin (IL)-4 plays a putative role in some forms of asthma. Thus, transgenic mice that overexpress murine IL-4 selectively within the lung were used to study the effect of IL-4 on mucus glycoprotein gene expression and mucin release. Histologic examination of lung sections from IL-4 mice revealed that nonciliated epithelial cells from conducting airways were hypertrophic, due at least in part to the accumulation of mucus glycoprotein. The cytoplasm of these cells stained positively for glycoproteins using mucicarmine, alcian blue (AB), and periodic acid-Schiff (PAS). Ciliated cells were also enlarged but did not show any mucin-specific staining. Inclusion granules typically found in nonciliated (Clara) cells of control mice were absent in the IL-4 transgenic mice. Northern blot analysis of total RNA from lung tissue revealed that the expression of the MUC5AC, but not MUC2, mucin gene was distinctly upgraded in IL-4 transgenic mice compared to transgene-negative controls. In addition, a 5- to 10-fold increase in AB- and PAS-positive material was found in lavage fluid from IL-4 overexpressing mice compared to transgene-negative controls. Thus, the overexpression of IL-4 locally within the lung enhances mucus glycoprotein synthesis by altering gene expression, results in the accumulation of mucus glycoprotein in nonciliated epithelial cells, and induces the release of mucus into the airway lumen. We therefore hypothesize that the overproduction of mucus seen in some patients with asthma may be a direct result of the action of IL-4 within the inflamed lung.     

Preservation of the anterior urethral ligamentous attachments in maintaining post-prostatectomy urinary continence: a comparative study

PURPOSE: The impact was determined on post-prostatectomy urinary incontinence of a technique preserving the anterior attachments of the proximal urethra to the posterior pubis by comparison to the results of other surgical methods. MATERIALS AND METHODS: Urinary continence in 51 patients undergoing preservation of the anterior urethral attachments was compared to that of 70 patients undergoing an anatomical prostatectomy with resection of the bladder neck, 55 patients with preservation of the bladder neck and 14 patients undergoing a dorsal vein gathering procedure. Comparisons were made for rate of total continence, time to return of continence, incidence of extra organ disease and operative blood loss. RESULTS: Total continence at 1 year was 84.3%, 89.1%, 85.7% and 100% respectively. Immediate total continence after catheter removal was seen in 25.5% after preservation of the anterior urethral attachments, 80.4% at 3 months compared to 41.4%, 50.9% and 50% at 3 months for anatomical prostatectomy with bladder neck resection, preservation and dorsal vein gathering. Clinical staging with the incidence of specimen confined disease was similar in all groups. Mean operative blood loss was 1,031 ml. for those patients undergoing anatomical prostatectomy compared to 681 ml. for those with preservation of the anterior urethral attachments. CONCLUSIONS: Preservation of the anterior urethral attachments results in improved urinary continence and lower operative blood loss without an increase in positive surgical margins.     

Potentiation of murine MCa-4 carcinoma radioresponse by 9-amino-20(S)-camptothecin

9-Amino-20(S)-camptothecin (9-AC) has demonstrated efficacy against several human cancer xenografts, including cancers of the colon, breast, lung, ovary, and stomach and malignant melanoma, and is currently undergoing Phase I clinical trials. In vitro data indicate that the addition of topoisomerase I inhibitors shortly after irradiation causes conversion of single-strand breaks to double-strand breaks, resulting in synergistic lethality to cultured log-phase or quiescent malignant cells. In our study, the efficacy of 9-AC as a potential radiosensitizing agent in vivo was assessed in C3Hf/Kam female mice bearing 7.6-8-mm MCa-4 mammary tumors implanted i.m. into the right posterior thigh. In one series of experiments to determine the dose dependence of 9-AC, mice were injected twice a week with either 0.5, 1.0, or 2.0 mg/kg 9-AC (total doses of 2, 4, and 8 mg/kg, respectively) either alone or 1 h before irradiation. In a second series of experiments, the schedule dependence of 9-AC was determined by giving a constant total dose of 4 mg/kg 9-AC once (2 mg/kg), twice (1 mg/kg every third day), or four (0.5 mg/kg every other day) times per week for 2 weeks, either alone or combined with radiation. The same radiation regimen was used in all experiments: 2-Gy fractions daily for 14 consecutive days, giving a total dose of 28 Gy to the tumor-bearing leg only. Tumor response was assessed by regrowth delay and dose modification factors (DMFs) obtained by comparing regrowth delay in the groups given 9-AC alone with those given the same dose of 9-AC and radiation. 9-AC significantly delayed tumor growth when combined with radiation, and this effect was dependent on drug dose; DMFs of 2.4 [95% confidence interval (CI), 2.0-3.1], 3.7 (95% CI, 3.1-4.6), and 3.3 (95% CI, 2.7-4.1) were obtained for groups treated with total drug doses of 2.0, 4.0, and 8.0 mg/kg 9-AC, respectively. In addition, the same total dose of 4 mg/kg 9-AC was more effective when given either twice or four times a week compared with once a week, giving DMFs of 2.8 (95% CI, 2.2-3.9), 2.6 (95% CI, 2.0-3.6), and 1.7 (95% CI, 1.3-2.4), respectively. The effect of 9-AC and radiation on normal tissue toxicity was assessed in two normal tissues, jejunum and skin, in separate groups of mice. Jejunal crypt cell survival was decreased in those mice given single doses of 9-AC ranging from 0.5-4.0 mg/kg and 12.5 Gy of total body radiation compared with those given 12.5 Gy of total body irradiation alone. The same regimen of drug and radiation did not modify acute skin reactions. These results suggest that 9-AC is an effective in vivo radiosensitizing agent when given in divided doses with fractionated irradiation. In addition, the gastrointestinal tract but not skin could be a critical target tissue for the use of 9-AC combined with radiation.     

Inter- and intraspecific variation in the diets of sympatric siamang (Hylobates syndactylus) and lar gibbons (Hylobates lar)

Studies of the siamang (Hylobates syndactylus continentis) and the lar gibbon (Hylobates lar lar) where they co-occur in mainland Asia have demonstrated interspecific dietary segregation based on body size and have suggested that observed levels of frugivory represent metabolically based maxima for these species. I studied sympatric groups of siamang (H. s. syndactylus) and lar gibbons (H. l. vestitus) at Ketambe in northern Sumatra (Indonesia) in order to assess the magnitude of within- and between-species variation in diets. The insular subspecies are considerably more frugivorous (60-70% of feeding time) than mainland conspecifics (35-50%). This is primarily because Sumatran hylobatids spend about twice as much time (approx. 45% of feeding) eating fig fruits (Ficus spp., Moraceae). A higher density of figs at Ketambe (compared to Kuala Lompat) may account for this behavioral difference. Enhanced frugivory has been achieved at the expense of folivory, which is much reduced in Sumatra--especially in H. lar (4% of diet)- and is limited almost entirely to immature foliage. The expected decline in protein intake resulting from diminished folivory in Sumatra may be counterbalanced by observed increases in insectivory, which is especially pronounced in lar gibbons. Interspecific dietary segregation emerges most clearly in how individuals of each species supplement their similarly fig-dominated diets. Siamang rely more on immature foliage--primarily from lianas, which generate young leaves more reliably and abundantly than trees do. Conversely, lar gibbons exploit the pulpy fruit of trees and lianas more heavily than siamang do. This general pattern occurs where the two species coexist in Malaysia, thereby suggesting a substantive interspecific difference that is somewhat greater in the insular populations.