Two-step synthesis of carbohydrates by selective aldol reactions     

Northrup AB  MacMillan DW 《Science (New York, N.Y.)》2004,305(5691):1752-1755

Studies of carbohydrates have been hampered by the lack of chemical strategies for the expeditious construction and coupling of differentially protected monosaccharides. Here, a synthetic route based on aldol coupling of three aldehydes is presented for the de novo production of polyol differentiated hexoses in only two chemical steps. The dimerization of alpha-oxyaldehydes, catalyzed by l-proline, is then followed by a tandem Mukaiyama aldol addition-cyclization step catalyzed by a Lewis acid. Differentially protected glucose, allose, and mannose stereoisomers can each be selected, in high yield and stereochemical purity, simply by changing the solvent and Lewis acid used. The reaction sequence also efficiently produces (13)C-labeled analogs, as well as structural variants such as 2-amino- and 2-thio-substituted derivatives.  相似文献   

Efficacy of tropicamide,homatropine, cyclopentolate,atropine and hyoscine as mydriatics in Angora goats     

NC Whelan  F Castillo-Alcala  I Lizarraga 《New Zealand veterinary journal》2013,61(6):328-331

Abstract

AIM: To document the efficacy of five commercially available mydriatics for their potential for diagnostic and therapeutic use in Angora goats.

METHODS: Over 8 weeks, the mydriatic effects of 1% tropicamide, 2% homatropine, 1% cyclopentolate, 1% atropine and 0.25% hyoscine were evaluated. Given as block treatments, drugs were applied randomly to one eye of 10 Angora goats, and the contralateral eye served as a control. Vertical and horizontal pupil diameters were measured to document onset ofeffect, time to reach a difference of 5 mm in the vertical/horizontal pupil diameter between eyes, time to maximum pupillary dilation, and duration of mydriatic action.

RESULTS: Onset of mydriasis for all drugs occurred within 15 minutes. Time to reach a difference of 5 mm in the vertical pupil diameter between eyes was shortest for 1% tropicamide and 0.25% hyoscine (0.5 h), then 2% homatropine and 1% atropine (0.75 h), and longest for 1% cyclopentolate (1.5 h). The maximum vertical pupillary dilation occurred earliest with 1% tropicamide and 1% atropine (2 h), followed by 0.25% hyoscine (3 h), 2% homatropine (4 h), and latest with 1% cyclopentolate (8 h). The duration of vertical dilation of the pupil was shortest with 1% tropicamide (6 h), then 2% homatropine (12 h), 1% cyclopentolate (12 h), 1% atropine (24 h), and longest for 0.25% hyoscine (96 h).

The time to reach maximum horizontal dilation of the pupil in treated eyes was shortest with 1% cyclopentolate (1 h), followed by 1% tropicamide (1.5 h), 0.25% hyoscine (3 h), 2% homatropine (3.5 h), and 1% atropine (4 h). The duration of horizontal pupil dilation was shortest with 1% tropicamide (4.5 h), and longest with 0.25% hyoscine (48 h).

CONCLUSION: All five mydriatics induced clinical dilation. Tropicamide (1%) had the shortest duration of effect, but gave incomplete dilation. Good dilation was achieved with 1% cyclopentolate and 2% homatropine, but took too long to reach maximum dilation for routine mydriasis. The largest vertical dilation of the pupil was achieved with 1% atropine and 0.25% hyoscine, but pupils remained dilated for more than 24 h.

CLINICAL RELEVANCE: For routine mydriasis in goats, it is recommended that 1% tropicamide be used, though there may be incomplete dilation. For a longer duration of mydriasis, such as in the treatment of anterior uveitis, 1% atropine or 0.25% hyoscine would be the drugs of choice.  相似文献   

Prospective Evaluation of Biweekly Streptozotocin in 19 Dogs with Insulinoma     

N.C. Northrup  K.M. Rassnick  T.L. Gieger  C.E. Kosarek  C.W. McFadden  M.P. Rosenberg 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2013,27(3):483-490

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Dexrazoxane treatment of doxorubicin extravasation injury in four dogs     

Venable RO  Saba CF  Endicott MM  Northrup NC 《Journal of the American Veterinary Medical Association》2012,240(3):304-307

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Variation among pathologists in histologic grading of canine cutaneous mast cell tumors.     

Nicole C Northrup  Barry G Harmon  Tracy L Gieger  Cathy A Brown  K Paige Carmichael  Anapatricia Garcia  Kenneth S Latimer  John S Munday  Pauline M Rakich  Lauren J Richey  Nancy L Stedman  An-Lin Cheng  Elizabeth W Howerth 《Journal of veterinary diagnostic investigation》2005,17(3):245-248

Ten veterinary pathologists at 1 veterinary institution independently assigned histologic grades to the same 60 canine cutaneous mast cell tumors (MCTs). There was significant variation among pathologists in grading the MCTs (P < 0.001). The probability of assigning a low grade was significantly higher for the pathologists in this study who use a published reference for histologic grading of canine cutaneous MCTs that allows subcutaneous MCTs or MCTs with mitotic figures to be included in the low-grade category (P < 0.0001 and P < 0.0001, respectively).  相似文献   

Variation among pathologists in the histologic grading of canine cutaneous mast cell tumors with uniform use of a single grading reference.     

N C Northrup  E W Howerth  B G Harmon  C A Brown  K P Carmicheal  A P Garcia  K S Latimer  J S Munday  P M Rakich  L J Richey  N L Stedman  T L Gieger 《Journal of veterinary diagnostic investigation》2005,17(6):561-564

Ten veterinary pathologists independently assigned histologic grades to the same 60 canine cutaneous mast cell tumors using the Patnaik classifications. The degree of agreement in grading among the pathologists was compared with the degree of agreement among the same pathologists in a previous study, in which each pathologist used the reference for grading that he/she uses routinely. Mean agreement improved significantly from 50.3% to 62.1% with uniform use of the Patnaik classifications (P = 0.00001), suggesting that there is value in uniform application of a single grading scheme for canine cutaneous mast cell tumors. Agreement among pathologists was still not 100%, suggesting that a more objective grading scheme should be developed and that other histologic indicators of prognosis should be investigated.  相似文献   

Retrospective study of orthovoltage radiation therapy for nasal tumors in 42 dogs     

Northrup NC  Etue SM  Ruslander DM  Rassnick KM  Hutto DL  Bengtson A  Rand W  Moore AS 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2001,15(3):183-189

Megavoltage radiation therapy currently is the standard of care for dogs with nasal tumors. Some studies report that surgery and adjunctive orthovoltage radiation therapy result in longer control of these tumors than does megavoltage radiation therapy alone. This study reports less effective control of nasal tumors in dogs treated with surgery and orthovoltage radiation than previously observed, supporting the superiority of megavoltage radiation therapy for these tumors. In addition, this study suggests 2 new prognostic indicators for dogs with nasal tumors and describes toxicity associated with surgery and orthovoltage therapy. Forty-two dogs with nasal tumors were treated with surgical cytoreduction and 48 Gy orthovoltage radiation therapy administered in twelve 4-Gy fractions. Median survival was 7.4 months. One- and 2-year survival rates were 37% and 17%, respectively. Dogs with facial deformity had shorter survival than those without deformity (P = .005). Dogs with resolution of clinical signs after treatment had longer survival than those with chronic nasal signs (P = .0001). Acute radiation toxicity was moderate to severe for skin and eye and negligible for oral mucosa. Toxicity healed within 1 month after radiation therapy. Late toxicity was mild, but 70% of evaluable dogs experienced persistent ocular signs. Only 39% of dogs achieved a disease-free period.  相似文献   

Neutropenia associated with vincristine and L-asparaginase induction chemotherapy for canine lymphoma   总被引：2，自引：0，他引：2  

Northrup NC  Rassnick KM  Snyder LA  Stone MS  Kristal O  Cotter SM  Moore AS 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2002,16(5):570-575

Vincristine (VCR) and L-asparaginase (L-ASP) are commonly used to treat canine lymphoma. As single agents, these drugs are not myelosuppressive. However, in combination, VCR and L-ASP cause severe neutropenia in some dogs. It has been recommended that L-ASP be administered 12-24 hours after VCR to minimize toxicity. The purpose of this retrospective study was to determine the prevalence of neutropenia after VCR/L-ASP induction therapy for canine lymphoma and to evaluate risk factors for myelosuppression, especially the interval between VCR and L-ASP administration. Medical records of 147 dogs were reviewed. L-ASP was given 0 (n = 50), 6 (n = 23), 18 (n = 20), or 24 (n = 54) hours after VCR. Forty percent of the dogs were neutropenic 7 days after VCR/L-ASP, and 18% had neutrophil counts of <1,000 cells/microL. The median neutrophil count was 3,712 cells/microL (range 0-30,968 cells/microL). No correlation was found between administration interval and day 7 neutrophil count (P = .84) or development of gastrointestinal signs, including vomiting (P = .80), diarrhea (P = .52), and decreased appetite (P = .30). No significant predictors of neutropenia were identified. Higher clinical stage and substage b were associated with decreased appetite after treatment (P = .04 and .01, respectively). Sixteen percent of the dogs were hospitalized. This study demonstrates that VCR/L-ASP induction for canine lymphoma may result in neutropenia but that separation of VCR and L-ASP administration may not be necessary to avoid toxicity.  相似文献   

Biological behaviour of canine mandibular osteosarcoma. A retrospective study of 50 cases (1999–2007)          下载免费PDF全文

V. J. Coyle  K. M. Rassnick  L. B. Borst  C. O. Rodriguez Jr  N. C. Northrup  T. M. Fan  L. D. Garrett 《Veterinary and comparative oncology》2015,13(2):89-97

The purpose of this retrospective study was to describe the biological behaviour of canine mandibular osteosarcoma (OSA) and to examine factors for their impact on metastasis‐free interval (MFI) and survival time (ST). Records from dogs treated with mandibulectomy for OSA (1999–2007) were reviewed. Archived tumour samples were evaluated for mitotic index (MI) and tumour grade. Fifty dogs were included, 21 received chemotherapy. Twenty‐nine dogs (58%) developed metastatic disease. The median MFI was 627 days, and median ST was 525 days. In univariate analysis MI > 40 was prognostic for decreased MFI and ST. Grade also influenced MFI and ST, with 5/21 (24%) dogs with grade II/III tumours metastasis‐free at one year versus 16/22 (72%) dogs with grade I tumours (P = 0.002); and 5/21 (24%) dogs with grade II/III tumours alive versus 17/22 (77%) dogs with grade I tumours (P = 0.001). In multivariate analysis, histological grade and adjuvant chemotherapy were prognostic for MFI and ST.  相似文献   

Effect of Recombinant Bovine Somatotropin on Plasma Concentrations of Insulin‐like Growth Factor I,Insulin and Membrane Integrity of Bull Spermatozoa     

MB Vieira  I Bianchi  EM Madeira  VFB Roll  CA Oliveira  P Viau  I Pivato  NC Severo  FAB Del Pino  A Schneider  MN Corrêa 《Reproduction in domestic animals》2010,45(6):1110-1113

This study aimed to evaluate the effect of the exogenous recombinant bovine somatotropin (rbST) on plasma concentrations of insulin‐like growth factor I (IGF‐I), insulin and semen quality of bulls. Twenty bulls (Aberdeen Angus and Brangus) were divided by breed into two groups. Placebo group was injected with NaCl 0.9% (s.c.) and treatment group with rbST (s.c., 500 mg) at days 0 and 14 of the experiment. Immediately after semen collection, blood samples were taken on days 0, 14, 28, 42 and 56 of the experiment. Semen was also collected on day 70 of the experiment. Evaluation of sperm motility was performed at pre‐freezing and post‐thawing stage, whereas assessment of sperm membrane integrity was performed after freezing and thawing. Analysis of data revealed that the effect of treatment and treatment‐by‐collection day on plasma concentrations of IGF‐I and insulin was not significant. However, mean plasma concentrations of IGF‐I and insulin were affected (p < 0.0001) by days of blood sampling. Effect of treatment and treatment‐by‐collection day on motility of spermatozoa was similar (p > 0.05) at pre‐freezing and post‐thawing stage. Intactness of plasmalemma and tail membrane of spermatozoa at post‐thawing stage was higher (p < 0.05) in rbST‐treated group than in control. In conclusion, rbST did not affect plasma concentrations of IGF‐I and insulin, however, it did improve post‐thaw sperm membrane integrity.  相似文献