Responses of dairy cows supplemented with somatotropin during weeks 5 through 43 of lactation

Beginning at wk 5 of lactation, 136 cows (34 per treatment) were supplemented daily for 38 wk with 0, 10.3, 20.6, or 41.2 mg of recombinantly derived bST monomer. Cows were obtained from University of Kentucky, University of Minnesota, University of Pennsylvania, and The Ohio State University. Nine cows (4 at 0 mg/d, 1 at 10.3 mg/d, 1 at 20.6 mg/d, and 3 at 41.2 mg/d) did not complete the experiment because of health problems. Data from these cows were included in the reproduction and health databases but not in the production database. Cows supplemented with bST produced more milk, consumed more feed, had lower rates of BW gain, and had improved efficiencies of milk production (conversion of feed and NEL to milk). Additional increases in productivity were modest at 20.6 and 41.2 mg/d versus productivity at 10.3 mg/d of bST. Concentrations of fat, protein, and TS in milk were unaffected. At 10.3 mg/d, bST did not adversely affect reproduction or health.     

Gas-liquid chromatography-mass spectrometry of hydroxy fatty acids as their methyl esters tert.-butyldimethylsilyl ethers

BACKGROUND: The objective of this paper is to illustrate the effect of a gap of 5 mm, an overlap of 5 mm and a perfect match on the dose distribution across the junction of tangential breast fields and adjacent supraclavicular and axillary fields. MATERIALS AND METHODS: For this purpose film dosimetry was applied to measure relative dose distributions in two sagittal planes in an anthropomorphic breast phantom having cork lungs, simulating a radiation therapy treatment of the breast and adjacent supraclavicular lymph nodes. Two different treatment techniques, an SSD match technique and a geometrically exact isocentric match technique, as routinely applied in the two institutes were examined. The three-dimensional treatment planning system of each institute was used to calculate the dose distribution in the match region of the supraclavicular fields and the two opposing tangential fields. The measured and calculated dose distributions were evaluated and compared along lines in two sagittal planes from the supraclavicular fields down to the tangential fields crossing the match planes. These dose distributions in the match region were extremely dependent on the set-up of the fields. RESULTS: Although the reproducibility of the film measurements was within 2%, it became clear that the set-up of the fields to achieve a gap of 5 mm, a perfect match or an overlap of 5 mm required a lot of attention, even when using a phantom. CONCLUSIONS: It can be concluded that in clinical practice, these set-up difficulties do influence the dose distribution in the match region much more than the systematic uncertainties in the dose calculation algorithms of the treatment planning systems and the type of treatment technique.     

Protein thermostability above 100 degreesC: a key role for ionic interactions

The discovery of hyperthermophilic microorganisms and the analysis of hyperthermostable enzymes has established the fact that multisubunit enzymes can survive for prolonged periods at temperatures above 100 degreesC. We have carried out homology-based modeling and direct structure comparison on the hexameric glutamate dehydrogenases from the hyperthermophiles Pyrococcus furiosus and Thermococcus litoralis whose optimal growth temperatures are 100 degreesC and 88 degreesC, respectively, to determine key stabilizing features. These enzymes, which are 87% homologous, differ 16-fold in thermal stability at 104 degreesC. We observed that an intersubunit ion-pair network was substantially reduced in the less stable enzyme from T. litoralis, and two residues were then altered to restore these interactions. The single mutations both had adverse effects on the thermostability of the protein. However, with both mutations in place, we observed a fourfold improvement of stability at 104 degreesC over the wild-type enzyme. The catalytic properties of the enzymes were unaffected by the mutations. These results suggest that extensive ion-pair networks may provide a general strategy for manipulating enzyme thermostability of multisubunit enzymes. However, this study emphasizes the importance of the exact local environment of a residue in determining its effects on stability.     

Familial transmission of a serious disease--producing group A streptococcus clone: case reports and review

Invasive group A streptococcus (GAS) infections are emerging diseases; however, person-to-person transmission of invasive GAS producing life-threatening infection has been observed rarely. We report a small intrafamilial cluster of life-threatening GAS infections. A previously healthy 47-year-old father developed necrotizing fasciitis of the neck. Two days later, his 16-year-old daughter developed streptococcal angina, pneumonia, and pleural empyema. Both patients had signs of streptococcal toxic shock syndrome. Pulsed field gel electrophoresis revealed that the M6 strains of GAS isolated from the father and daughter had identical patterns. Cases of person-to-person transmission of invasive GAS infection reported in the literature are also reviewed.     

Genomic organization of the human TIMP-1 gene. Investigation of a causative role in the pathogenesis of X-linked retinitis pigmentosa 2

PURPOSE: To evaluate the role of TIMP-1 in inherited retinal degeneration. METHODS: The genomic structure of the TIMP-1 gene was established and male patients with x-linked retinitis pigmentosa 2 from five families were screened for sequence alterations by direct sequencing in all exons, exon-intron boundaries, and the 5' upstream region of the gene. RESULTS: TIMP-1 appears to be expressed in the retina at low levels and consists of six exons spanning a genomic region of approximately 4.5 kb on Xp11.23. No disease-specific sequence alterations were identified. A site substitution in exon 5 was observed in samples from control subjects and patients, but it did not alter the amino acid sequence of the protein product. CONCLUSIONS: The results of this study exclude mutations in the TIMP-1 coding sequence, splice sites, and the 5' upstream region as a cause of retinal degeneration in x-linked retinitis pigmentosa 2. However, an as yet unidentified regulatory element that lies outside these intervals may be implicated. The role of this tightly regulated protein in the normal functioning of the retina has yet to be determined.     

Dynamics of cyanide binding to ferrous Scapharca inaequivalvis homodimeric hemoglobin

Flash photolysis experiments have been carried out for the first time on a hemoglobin ferrous cyanide adduct with an 8 ns laser pulse. A 95% nonexponential rebinding process occurs within 2 micros after full photolysis in ferrous cyanide dimeric Scapharca inaequivalvis hemoglobin (HbI), indicating that once photolyzed the cyanide anion is not able to escape from the protein matrix and rebinds to the heme iron. The resonance Raman spectrum of the 10 ns photoproduct is identical to that of the fully relaxed deoxy derivative, indicating that in the ferrous cyanide HbI adduct protein relaxation occurs within 10 ns after photolysis. This behavior is at variance with that of the carbonmonoxy HbI derivative in which very little geminate rebinding is observed and the photoproduct relaxes with a lifetime of 1 micros. The fast relaxation of the cyanide HbI photoproduct can be accounted for by the small perturbation of the heme structure induced by cyanide binding to ferrous HbI. This is consistent with a deoxy-like conformation of the HbI ferrous cyanide adduct and implies that the pathway for relaxation involves only minor local rearrangements of the heme moiety. Photolysis experiments carried out on ferrous cyanide horse myoglobin, which can be saturated only partially, show a qualitatively similar behavior in ligand rebinding, indicating that the geminate process of the cyanide anion is a general phenomenon in hemoproteins.