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Biomedical subjects

M Sarwar

Publications and source records attributed to M Sarwar.

At least 19 recordsLinked to original sources

Effects of varying forage and concentrate carbohydrates on nutrient digestibilities and milk production by dairy cows.

Five Holstein cows with ruminal cannulas were used in a 5 x 5 Latin square design to determine the effect of replacing forage NDF with soyhull NDF and varying concentrations of nonstructural carbohydrates on nutrient digestion and milk production. Diets in which NDF percentage from forage (corn silage: alfalfa hay, 1:1) was 80 (control), 70, or 60 were formulated by substituting soyhulls for forage; total forage was 43.2, 36.7, and 31.1% of the diets, respectively, but total NDF was 31%. Nonstructural carbohydrates were formulated to be 47 (control), 35, or 25% by substituting soyhulls, roasted soybeans, and Ca soaps for concentrate. Ruminal acetate: propionate ratio decreased linearly when diets lower in forage NDF were fed, but it increased quadratically when dietary nonstructural carbohydrates were reduced. Apparent digestibility of OM increased quadratically, but NDF digestibility and lactation performance were unaffected when diets lower in forage NDF were fed. Digestibility of NDF increased linearly when nonstructural carbohydrates were reduced, perhaps because of greater digestibility of soyhull NDF and smaller negative associative effects. Fat from soybeans and Ca soaps was increased as nonstructural carbohydrates decreased. Added fat probably increased fatty acid digestibility and decreased milk protein percentage. Greater FCM production without correspondingly greater feed intake or BW loss increased feed efficiency as nonstructural carbohydrates decreased. In dairy rations containing soyhulls, 60% of dietary NDF from forage should maintain lactation performance, and decreasing nonstructural carbohydrates to 25 to 35% of feed DM, coupled with adding dietary fat, may decrease negative associative effects and improve efficiency of milk production.

Ammonia

Cloning of aminoglycoside phosphotransferase (APH) gene from antibiotic-producing strain of Bacillus circulans into a high-expression vector, pKK223-3. Purification, properties and location of the enzyme.

The aminoglycoside phosphotransferase gene from a butirosin-producing strain of Bacillus circulans was cloned in a high-expression vector (pKK223-3) to give the recombinant plasmid pMS5. Escherichia coli harbouring the plasmid, E. coli JM103[pMS5], was characterized, and several features of the expression of the phosphotransferase were studied. The phosphotransferase activity was best expressed in a medium lacking glucose, and the highest levels of the enzyme were found between 12 and 24 h of growth. The induction of the phosphotransferase expression with isopropyl beta-D-thiogalactopyranoside (inducer) was found to be undesirable as the overproduction of the enzyme led to the killing of the bacteria. The subcellular location of the phosphotransferase, and also the site in vivo of the phosphorylation of neomycin, was found to be in the cytoplasm. The phosphotransferase was purified to homogeneity in good yield (17 mg of purified protein/3 litres of culture) and was shown to be a monomer of Mr 30,000-32,000. The N-terminal amino acid sequence was in agreement with that predicted from the gene sequence and confirmed the absence of any signal sequence. The regiospecificity of the phosphotransferase reaction was studied by m.s. and by 1H-, 13C- and 31P-n.m.r. using ribostamycin as the substrate, and it was found that the antibiotic was phosphorylated at the 3'-hydroxy group.

Amino Acid Sequence

The Dens-Arch synchondrosis versus the Hangman's fracture.

The synchondrosis between the dens and arch of C2 is a normal structure in infants and children. It is not visible on lateral views of the cervical spine, but is routinely visible on oblique views. In such cases it has a distinct tendency to mimic a C2-arch fracture. The varying appearance of this synchondrosis and its differentiation from a true fracture of C2 are the subjects of this report.

Arthrography

The posteriorly tilted dens. A normal variation mimicking a fractured dens.

The normal dens occasionally can be posteriorly tilted and in such cases, can mimic a fractured, posteriorly tilted, dens. Differentiation of the two conditions depends on: [1] knowledge that this normal variation of the dens occurs, and [2] demonstrating that no fracture exists. In many cases, this latter determination can be accomplished on plain films, but in other cases, laminography is required.

Axis, Cervical Vertebra

Intracerebral venous angioma. Case report and review.

Only a few cases of angiographically demonstrated and pathologically proved cases of venous angiomas have been published. In contrast to the scarcity of recorded cases of angiographically studied venous angiomas, they are the most common incidentally encountered angiomatous lesions at autopsy. Their angiographic characterization, though highly suggestive, is not pathognomonic. The angiographic characteristics include small radiating veins that drain into a larger transcerebral vein that in turn empties into a dural sinus; blush and early draining veins also may be seen. The differential diagnosis includes telangiectasia, infiltrating glioma, and probably a cavernous angioma. We report an angiographically demonstrated and pathologically proved case of a venous angioma and also review the literature.

Adult

Persistence of the dens as the body of C1. A case report of a rare anomaly.

A patient with persistence of the dens as the body of the first cervical vertebra is described. This is an extremely rare anomaly and in this patient was associated with instability of the first cervical vertebra. Embryologic considerations and the clinical implication- of this anomaly are discussed.

Adult

Decrease in ventricular and sulcal size after death.

Fifty-one intact corpses were examined with the EMI head scanner from 1 1/2-52 hours after death; 15 of these had antemortem CT scans. Seven had sequential postmortem CT scans. CT scans and autopsy findings for lateral ventricular size and sulcal width were compared. The lateral ventricular size generally, and the sulcal width occasionally, became smaller after death, though the decrease was usually mild. This decrease was demonstrated not only on antemortem and postmortem sequential CT scans, but on postmortem sequential CT scans alone as well.

Autopsy

The sella in childhood hypothyroidism.

Two sellar configurations have been noted in primary childhood hypothyroidism. In the older child the sella appears unusually round and slightly enlarged, and the term "cherry" sella has been used to describe its appearance. Enlargement is due to rebound hypertrophy of the pituitary gland and is reversible with adequate, early treatment. If reversal of these changes is not accomplished one should consider the possibility of an adenoma having developed. In the young child an infant the sella appears more immature and "bowl-like". Enlargement is not a prominent feature in this age group, and indeed was difficult to detect with certainty. Both configurations, but especially the "cherry" sella of the older child, are characteristic enough to enable one to suggest the diagnosis of primary hypothyroidism from lateral skull films.

Adolescent

Anterior pontomesencephalic vein and basilar artery in exophytic brainstem gilioma.

The angiographic differentiation of an intrinsic exophytic brainstem glioma from an extra-axial posterior fossa tumor is not always easy. The location of the basilar artery alone may not be significant. Displacement of the anterior pontomesencephalic vein anterior to the basilar artery appears to be a reliable indicator of an intrinsic exophytic brainstem glioma.

Adolescent