Sonography of gallstones and biliary dilatation without a visible aetiology: the infrequency of obstructing choledocholithiasis.

This paper describes 50 consecutive patients who sonographically had gallbladder stones and dilated bile ducts, but no visible aetiology for the dilatation. We reviewed these cases to determine the frequency of choledocholithiasis in this setting. Common duct stones caused obstruction in only 36% of these patients. Other aetiologies included strictures due to chronic pancreatitis or prior stone passage in 24% of the patients, and malignant obstruction in 16%. In 24% of the patients, no cause was found for biliary dilatation; common duct stones or obstructing tumours were excluded in the group. Since aetiologies other than stones are likely in a majority of cases, further preoperative workup (CT, percutaneous transhepatic cholangiography, ERCP) or intraoperative cholangiography (if the patient requires urgent cholecystectomy) is indicated. The additional studies should provide a diagnosis, help determine whether or not the common duct should be explored, or avoid unnecessary operation in case of incurable malignancy.

A modification of the Otis urethrotome as an aid to fascial dilation of percutaneous nephrostomy tracts.

An Otis urethrotome has been modified by drilling a 3/64-inch hole through the tip to permit passage into the kidney over a 0.038-inch guide wire. This instrument has been used to aid in the performance of 12 nephrostomy tract dilations without significant complications. When compared to 10 Amplatz tract dilations, the modified Otis method required an average of 3.6 minutes versus 8.7 minutes to dilate the nephrostomy tract to 24F. Ease of tract dilation as well as decreased time to dilate make this technique a useful adjunct to standard nephrostomy tract dilation techniques.

Wedge and subselective pulmonary angiography in pulmonary hypertension secondary to venous obstruction.

Pulmonary wedge or subselective angiography provided key diagnostic information in two cases of pulmonary hypertension secondary to pulmonary venous obstruction. Whereas conventional pulmonary angiograms and ventilation-perfusion lung scans were interpreted as showing embolism, plain radiographs demonstrated Kerley B lines, suggesting venous obstruction. Subselective or wedge angiography of nonopacified arteries verified their anatomical patency and also revealed venous stenoses, collaterals, and atrophy indicative of obstruction.

Dehorning the mature goat.

Surgical techniques for dehorning the mature goat utilized combinations of sedation and local anesthesia. Numerous factors were considered before surgery was performed. Use of Barne's calf dehorners, tube-type calf dehorners, and elastrator bands are contraindicated in the goat due to the anatomic structure of the frontal sinus. Dehorning female goats late in gestation can induce aboriton; male goats used for breeding should be dehorned well in advance of the breeding season. Owners should be advised that dehorning can be temporatily debilitating to the goat and can alter a goat's social status within a herd.

Interactions of differentiated primary sex factors in Chironomus tentans.

Different populations of Chironomus tentans, possibly representing geographically isolated races, have two differentiated genic mechanisms of sex determination involving either a dominant male-determining factor in the left arm of chromosome 1 or a dominant female-determining factor at the right tip of chromosome 1. In crosses between these populations, the male-determining factor is epistatic to the female-determining factor. No evidence of intersexuality has been found in such crosses.

Refinement of the Crystal Structure of the Aragonite Phase of CaCO3.

Aragonite (CaCO3) crystallizes in the unit cell a = 4.9598(5) Å, b = 7.9641(9) Å, and c = 5.7379(6) Å at 25 °C with four formula weights in space-group Pmcn. The structure has been refined to R w = 0.024, R = 0.040 using 765 x-ray reflections from a single crystal. The Ca ion is coordinated to nine oxygens with Ca … O distances in the range 2.414(2) Å to 2.653(1) Å. The two unique C-O distances in the CO3 group are 1.288(2) Å (on the mirror plane) and 1.283(1) Å. The two unique O-C-O angles are 119.6(2)° (across the mirror plane) and 120.13(8)°. The distances and angles in the CO3 group are not significantly different at the 95 percent confidence level.

The Crystal Structure of BaCa(CO3)2 (barytocalcite).

The barytocalcite phase of BaCa(CO3)2 crystallizes in the monoclinic unit cell a = 8.092(1) Å, b = 5.2344(6) Å, c = 6.544(1) Å, ß = 106.05(1)° at 25 °C with cell contents of 2[BaCa(CO3)2]. The structure previously reported by Alm is correct in its coarse details but has been redetermined here and refined to R w = 0.028, R = 0.023 in space-group P21/m using 1652 observed reflections. Corrections were made for absorption, isotropic extinction, and anomalous dispersion. The structure of barytocalcite has an … ABCABC … stacking of cation layers and repeat every 3 layers. The calcite phase of CaCO3 has an ABC cation layer sequence and repeats every 6 layers. The orientations of the CO3 groups in barytocalcite are like the CO3 group orientation in the aragonite phase of CaCO3, and are rotated about 30 ° from the CO3 group orientation in calcite. The cation layer sequence in aragonite is … ABAB … and the structure repeats every 2 layers. The Ca ion in barytocalcite is coordinated to seven oxygens, including an edge of a CO3 group, with Ca … O distances in the range 2.305(2) Å to 2.518(2) Å. The Ba ion is coordinated to five edges and one apex of the CO3 groups with Ba … O distances ranging from 2.729(3) Å to 3.140(2) Å. The distances of the C atoms in the CO3 groups from the planes of the O atoms are 0.025(5) Å and 0.022(4) Å for C(l) and C(2). respectively.