Crude protein oscillation in diets adequate and deficient in metabolizable protein: Effects on nutrient digestibility, nitrogen balance, plasma amino acids, and greenhouse gas emissions.

Reducing dietary CP is a well-established means to improve N use efficiency. Yet, few studies have considered if transient restrictions in dietary CP could reduce the environmental footprint of late-lactation cows. We hypothesized that the effects of CP feeding pattern on digestibility and environmental outputs would be amplified at lower dietary CP. We tested CP levels below and near predicted requirements (low protein [LP], 13.8%; high protein [HP], 15.5%) offered in 2 feeding patterns: where diets alternated ±1.8 percentage units CP every 2 d (oscillating [OF]) or remained static. Our study used a 2 × 2 factorial design with 16 mid- to late-lactation Holsteins (mean = 128, SD = 12 DIM), divided into rumen-cannulated (n = 8) and noncannulated subsets (n = 8). For each 28-d experimental period, we recorded feed intake and milk production and took samples of orts (1×/d) and milk (2×/d) for 4 d. For the cannulated subset, we measured and sampled from the total mass of feces and urine production and collected plasma 2×/d across 4 d. For the noncannulated subset, we sampled carbon dioxide and methane emissions 3×/d for 4 d. For each subset, we fit linear mixed models with fixed effects for CP level, CP feeding pattern, the interaction of CP level and CP feeding pattern, period, and a random effect for cow. For plasma and urinary urea-N, we conducted time series analysis. Contrary to our hypothesis, we found no evidence that dietary CP level and CP feeding pattern interacted to influence N balance, nutrient digestibility, or gas emissions. Results showed HP resulted in similar milk N but increased manure N, reducing N use efficiency (milk true protein N/intake N) relative to LP. For OF, urea-N in urine and plasma peaked 46 to 52 h after the first higher-CP phase feeding. Nutrient digestibility and gas emissions were similar across treatments, except CO2 production was greater for OF-HP. In summary, measured variables were minimally affected by dietary CP alternating ±1.8 percentage units every 48 h, even when average dietary CP was fed below predicted requirements (LP). Although our findings suggest that mid- to late-lactation cows are resilient to oscillation in dietary CP, oscillating CP neither reduced the environmental footprint by improving nutrient use efficiencies nor reduced the potential for direct and indirect greenhouse gas emissions.

Regiospecificity assignment for the reaction of kanamycin nucleotidyltransferase from Staphylococcus aureus.

Aminoglycoside nucleotidyltransferases catalyze the transfer of a nucleoside monophosphoryl group from a nucleotide to a hydroxyl group of an aminoglycoside antibiotic. Kanamycin nucleotidyltransferase [ANT (4',4' ')-I] from Staphylococcus aureus confers resistance to numerous aminoglycosides with a 4' or 4' ' hydroxyl group in the equatorial position. The synthesis of m-nitrobenzyl triphosphate, a new substrate of kanamycin nucleotidyltransferase, is reported. The kanamycin nucleotidyltransferase catalyzed reaction of kanamycin A with m-nitrobenzyl triphosphate is 2 orders of magnitude slower than that with ATP. The MALDI-TOF spectra of the purified products of both reactions revealed that kanamycin A was modified only at one position. The regiospecificity of the reaction catalyzed by kanamycin nucleotidyltransferase of kanamycin A with either ATP or m-nitrobenzyl triphosphate was determined directly by one- and two-dimensional hetero- and homonuclear NMR techniques. The site of the modification was unambiguously assigned to the 4' hydroxyl of kanamycin A; thus, the products formed are 4'-(adenosine-5'-phosphoryl)-kanamycin A and 4'-(m-nitrobenzyl phosphoryl)-kanamycin A. This eliminates the uncertainty concerning the point of modification since this could not be determined from the crystal structure of the enzyme with bound MgAMPCPP and kanamycin A [Pedersen, L. C., Benninig, M. M., and Holden, H. M. (1995) Biochemistry 34, 13305-13311].

Prostaglandins and nicotinate-provoked increase in cutaneous blood flow.

The mechanism of topically applied methyl nicotinate-induced local cutaneous erythema was studied in normal human subjects. Aqueous methyl nicotinate (0, 0.1, 1.0, 10.0, and 100 mmol/L) was applied to the volar forearms in quadruplicate after oral pretreatments with 25 mg doxepin hydrochloride, 600 mg ibuprofen, 50 mg indomethacin, 975 mg aspirin, and lactose placebo. The cutaneous vascular response was monitored by laser Doppler velocimetry. Although doxepin did not affect the cutaneous vascular response to methyl nicotinate, indomethacin, ibuprofen, and aspirin significantly suppressed the response. Because indomethacin, ibuprofen, and aspirin have different chemical structures, the common property of inhibition of the response to methyl nicotinate may be assigned to their common pharmacologic action, i.e., inhibition of prostaglandin bioformation.

Lichenoid eruption produced by captopril.

Captopril, an oral active dipeptidylcarboxypeptidase inhibitor with antihypertensive properties, has been reported to have the following cutaneous side effects: macular and papular skin eruptions, urticaria, angioedema, mouth ulcers, pemphigus, and pityriasis rosea-like eruptions. Here, to the best of our knowledge, is the first case in which a pityriasis rosea-like eruption evolved into a lichenoid drug eruption. Also discussed is the remarkable similarity in the side effects of captopril, gold compounds, d-penicillamine, and organic mercurials.

Pityriasis rubra pilaris as the initial manifestation of leukemia.

The association of pityriasis rubra pilaris (PRP) with an underlying disease is unusual. A case of a PRP-like eruption presenting as the initial manifestation of acute stem cell leukemia is reported. Other noncutaneous diseases previously reported in association with PRP are reviewed. Other cutaneous lesions associated with leukemia are also briefly described.

Buschke-ollendorff syndrome.

Buschke-Ollendorff syndrome or dermatofibrosis lenticularis disseminata with osteopoikilosis is a rare autosomal dominant condition characterized by focal sclerotic bone dysplasia and associated connective tissue nevi. The following case report not only illustrates classic findings in this disease but also demonstrates previously reported, but little known features.