Plus-end motors override minus-end motors during transport of squid axon vesicles on microtubules.

Plus- and minus-end vesicle populations from squid axoplasm were isolated from each other by selective extraction of the minus-end vesicle motor followed by 5'-adenylyl imidodiphosphate (AMP-PNP)-induced microtubule affinity purification of the plus-end vesicles. In the presence of cytosol containing both plus- and minus-end motors, the isolated populations moved strictly in opposite directions along microtubules in vitro. Remarkably, when treated with trypsin before incubation with cytosol, purified plus-end vesicles moved exclusively to microtubule minus ends instead of moving in the normal plus-end direction. This reversal in the direction of movement of trypsinized plus-end vesicles, in light of further observation that cytosol promotes primarily minus-end movement of liposomes, suggests that the machinery for cytoplasmic dynein-driven, minus-end vesicle movement can establish a functional interaction with the lipid bilayers of both vesicle populations. The additional finding that kinesin overrides cytoplasmic dynein when both are bound to bead surfaces indicates that the direction of vesicle movement could be regulated simply by the presence or absence of a tightly bound, plus-end kinesin motor; being processive and tightly bound, the kinesin motor would override the activity of cytoplasmic dynein because the latter is weakly bound to vesicles and less processive. In support of this model, it was found that (a) only plus-end vesicles copurified with tightly bound kinesin motors; and (b) both plus- and minus-end vesicles bound cytoplasmic dynein from cytosol.

Risks of synchronous gastrointestinal or biliary surgery with splenectomy for hematologic disease.

BACKGROUND: The addition of splenectomy to a gastrointestinal (GI) operation may have an adverse effect on mortality, morbidity, and even survival. OBJECTIVE: To determine the risks of the converse: synchronous GI surgery appended to splenectomy for hematologic diseases. DESIGN: Retrospective cohort. SETTING: Multiple hospitals comprising an affiliated surgical training program. PATIENTS: Consecutive sample of 207 adults (mean age, 49 years) with splenectomies for hematologic diseases. INTERVENTION: Splenectomy and concomitant GI or biliary surgery (group 1, n=19) and splenectomy alone (group 2, n=188). MAIN OUTCOME MEASURES: Length of hospital or intensive care unit stay, later operations, postoperative infections, postoperative abdominal abscess, major complications, and death. RESULTS: Preoperative and intraoperative factors were similar in both groups. Operative mortality was 3 of 19 in group 1 and 8 of 188 in group 2 (p=.07). The mean number of major complications tended to be higher in group 1 (1.5 vs 0.5, P=07). Despite no difference between the incidences of overall postoperative infections, patients in group 1 were much more likely to develop an abdominal abscess (4 of 19 vs 3 of 188, P=.002). Logistic regression established that patients undergoing splenectomy and synchronous GI or biliary surgery were 25 times more likely to develop an intra-abdominal abscess than were patients with splenectomy alone, even controlling for confounding factors (odds ratio, 24.7; 95% confidence interval, 3.1 to 196; P=.002). CONCLUSIONS: Synchronous GI or biliary surgery with splenectomy for hematologic disease increases the risk of intra-abdominal abscess and should be avoided. Complication and mortality rates may also be increased.

Lip reconstruction following Mohs' surgery: the role for composite resection and primary closure.

Surgical outcomes and patient satisfaction with composite resection and primary closure for the management of upper-lip defects following Mohs' surgery were evaluated. Twenty-seven patients underwent upper-lip reconstruction following Mohs' surgery from 1993 to 1997. Twelve of these patients were selected for this report based on adequate follow-up examinations and photographs. There were nine women and three men with a mean age of 46 years (range, 33 to 70 years). Eleven patients underwent Mohs' surgery for basal cell carcinoma and one patient for squamous cell carcinoma of the upper lip. The defects varied in size and location, often extending beyond a single aesthetic subunit. The reconstruction was performed an average of 7 days after Mohs' surgery (range, 1 to 23 days). In 50 percent of the cases, a full-thickness excision was performed, which included orbicularis oris and inner-lip mucosa. The functional results were graded as near normal to normal in all cases. There were no observed changes in oral continence, eating or speech. Two patients experienced numbness medial to the operative site, but this had no adverse affect on lip function. The aesthetic results were graded as very good to excellent in all cases. Eleven of the 12 patients were satisfied with their lip appearance and function. Conventional wisdom dictates that during reconstruction of upper-lip defects, one should attempt to maintain a majority of the uninvolved tissue for the best result. Although these techniques result in wound closure, they fail to consider lip aesthetics. By using a vertically oriented composite resection of the tipper lip with the additional resection of uninvolved tissue, normal lip architecture is maintained. In our experience, this results in a superior aesthetic and functional result.

National plastic surgery survey: brow lifting techniques and complications.

The purpose of this survey was to assess trends in brow lifting philosophy, techniques, and complications. This is the second of a three-part survey; the first part reported on complications with face lift techniques, and the final report will address practice management issues, including facility and ancillary procedures. Surveys were sent to 3800 members of the American Society of Plastic Surgeons; the response rate was 15 percent. This survey represents data on 6951 brow lifts, of which approximately 50 percent were performed endoscopically and 50 percent with a coronal incision. Several conclusions about the practice of the respondents were reached: (1) Both brow lift techniques were considered to be effective. (2) Surgeons considered coronal brow lifting to be more effective for the three basic goals of brow lifting: brow elevation, reduction of transverse lines, and reduction of glabellar lines. (3) Reported complication rates for both techniques were low, and the most frequent complication was alopecia (varying from 2.9 percent to 4 percent). (4) Patient satisfaction varied from 98.2 percent to 99.2 percent. (5) Major complications were rarely reported.

In vitro evaluation of nicotinamide riboside analogs against Haemophilus influenzae.

Exogenous NAD, nicotinamide mononucleotide, or nicotinamide riboside is required for the growth of Haemophilus influenzae. These compounds have been defined as the V-factor growth requirement. We have previously shown that the internalization of nicotinamide riboside is energy dependent and carrier mediated with saturation kinetics. Thionicotinamide riboside, 3-pyridinealdehyde riboside, 3-acetylpyridine riboside, and 3-aminopyridine riboside were prepared from their corresponding NAD analogs. These compounds and several other nicotinamide riboside analogs were evaluated for their ability to support the growth of H. influenzae and for their ability to block the uptake of [carbonyl-14C]nicotinamide riboside by H. influenzae. 3-Aminopyridine riboside blocked the uptake of [carbonyl-14C]nicotinamide riboside and inhibited the growth of H. influenzae when NAD, nicotinamide mononucleotide, or nicotinamide riboside served as the V factor. The antibacterial activity of 3-aminopyridine riboside was found to be specific for H. influenzae but had no effect on the growth of Staphylococcus aureus or Escherichia coli. In additional experiments by reversed-phase high-performance liquid chromatography, it was determined that whole cells of H. influenzae degrade 3-aminopyridine adenine dinucleotide to 3-aminopyridine riboside, which is then internalized. Inside the cell, 3-aminopyridine riboside has the ability to interfere with the growth of H. influenzae by an undetermined mechanism.