N-acyl 3-alkylidenyl- and 3-alkyl azetidin-2-ones: a new class of monocyclic beta-lactam antibacterial agents. 1. Structure-activity relationships of 3-isopropylidene and 3-isopropyl analogs.

The synthesis and antibacterial activity of a series of N-acyl 3-isopropylidenyl- and 3-isopropyl 2-azetidinones having potent in vitro antibacterial activity, particularly against anaerobic organisms, is described. A distinguishing structural feature of these compounds is the lack of any ionizable moiety appendant to the lactam nitrogen.

Polymorphic aspects of male anthropoid honing premolars.

A recent study has indicated that heritage may be an important component in explanations of interspecies variation in male anthropoid maxillary canines. To further test this hypothesis, comparative data for the maxillary canine's occlusal partner, the honing mandibular premolar, are presented. Relative to body mass, measurements of the honing premolar--length of the honing facet, mesiodistal length, and buccolingual breadth and shape (as expressed by the ratio of length to breadth)--show a similar but stronger heritage component than measurements of the maxillary canine.

HIV risk behavior in drug users: increased blood "booting" during cocaine injection.

The practice of "booting" or "kicking," in which blood is drawn into the syringe and then injected, was assessed as a possible behavioral mechanism contributing to cocaine's association with increased human immunodeficiency virus (HIV) infection. Intravenous drug users (IVDUs) (N = 68) demonstrated (with an empty, needleless syringe) their usual style of injection of cocaine, heroin, and speedball, in random order. The experimenter recorded the injection procedures and the syringe volumes at each step.

Deep venous thrombosis in the baboon: an experimental model.

Experimental models of deep venous thrombosis, heretofore, have not been available for laboratory studies. This investigation establishes a novel model of venous thrombosis by inhibiting the protein C system combined with venous stasis and subtle venous injury. Ten adolescent baboons were studied in pairs, with one animal receiving saline solution (B2, B4, B6, B8, B10) and one being exposed to thrombogenic reagents (B1, B3, B5, B7, B9).

Results of a multicenter study of the modified hook-titanium Greenfield filter.

Initial efforts to modify the stainless steel Greenfield filter for percutaneous insertion led to development of a titanium Greenfield filter, which could be inserted by use of a 12F carrier. This device functioned well as a filter but had an unacceptable 30% rate of migration, tilting, and penetration. Therefore a titanium Greenfield filter with modified hooks was developed and has been tested in 186 patients at 10 institutions.

Evaluation of a new percutaneous stainless steel Greenfield filter by intravascular ultrasonography.

The standard stainless steel Greenfield filter was modified by extending the limbs at the apex to permit loading into a 12F carrier for percutaneous insertion. This model was tested for fixation and resolution of experimental embolism in dogs (six filters in four dogs) and sheep (eight suprarenal filters in eight sheep). Serial radiographs and venacavography at 2 and 4 weeks allowed measurement of migration and suspected caval penetration, confirmed by direct examination at autopsy.

Clinical characteristics and surgical management of vascular complications in patients undergoing cardiac catheterization: interventional versus diagnostic procedures.

The purpose of this report is to define the clinical characteristics and outcome of surgical management of vascular complications after interventional cardiac catheterization and to contrast them to those after diagnostic cardiac catheterization. From October 1985 to December 1989, 101 patients were treated for 106 vascular complications after 1866 interventional and 5046 diagnostic cardiac catheterizations at the University of Michigan Medical Center. Interventional catheterizations resulted in 69 vascular complications in 64 patients (frequency 3.

Evaluation of the inferior vena cava with intravascular US after Greenfield filter placement.

An animal model was used to evaluate the utility of intravascular ultrasound (US) imaging of the inferior vena cava (IVC) following Greenfield filter placement. Ten Greenfield filters were placed in the IVCs of five sheep and three dogs. Experimentally induced thrombi were injected into four filters at the time of placement.

Lower extremity arterial disease in systemic lupus erythematosus.

Lupus vasculitis primarily affects microvascular circulation, and large-vessel thrombosis is a rare complication of this disease. Large-vessel occlusive disease in systemic lupus erythematosus is most likely related to hypercoagulability in addition to immune complex-mediated endothelial damage. We describe the 11th and 12th patients reported to have systemic lupus erythematosus and macrovascular occlusive disease of the lower extremities.

Polymorphic aspects of male anthropoid canines.

Interspecific variation in the architecture of male anthropoid maxillary canines is documented. Extant taxa are polymorphic, and most can be sorted into two major groupings based on quantitative measures of shape, distal edge sharpness, and interspecific changes in their linear dimensions (projection, mesiodistal length, and buccolingual breadth) relative to each other and to body mass (scaling). One group includes the great apes and ceboids; the other includes cercopithecoids and hylobatids.

Xenopus oocyte K+ current. II. Adenylyl cyclase-linked receptors on follicle cells.

Xenopus ovarian follicles consist of single large oocytes surrounded by a layer of small follicle cells that are coupled to the oocyte by gap junctions. Hyperpolarizing K+ currents can be detected in the oocytes of follicles stimulated with adenosine, isoproterenol, follicle-stimulating hormone (FSH), or microinjected adenosine 3',5'-cyclic monophosphate (cAMP). We show that cAMP accumulation can be detected in follicles incubated with the adenosine agonist 5'-N-ethylcarboxamidoadenosine (NECA), isoproterenol, or FSH, but only if forskolin and a phosphodiesterase inhibitor are also added.

Xenopus oocyte K+ current. I. FSH and adenosine stimulate follicle cell-dependent currents.

Ovarian follicles of Xenopus laevis frogs consist of a single large oocyte surrounded by follicle cells attached to the oocyte by gap junctions. Adenosine has been found to activate an outward K+ current in follicles. This response is reduced by microinjection of protein kinase inhibitor (PKI), suggesting that adenosine 3',5'-cyclic monophosphate (cAMP) mediates the response.

Xenopus oocyte K+ current. III. Phorbol esters and pH regulate current at gap junctions.

Xenopus follicles consist of a single large oocyte surrounded by a monolayer of follicle cells attached to the oocyte by gap junctions. Adenosine 3',5'-cyclic monophosphate (cAMP) activates an outward K+ current which is completely abolished if follicle cells are removed or if phorbol esters (which have been reported to reduce gap junctional conductance) are added. In this study we show that phorbol esters do not reduce cAMP levels in follicles and that acid pH, another known stimulus for reducing gap junctional conductance, mimics the action of phorbol esters to inhibit the cAMP-stimulated K+ current.

Long-term results of aortoiliac reconstruction.

To facilitate evaluation of new and evolving interventional strategies in the management of aortoiliac occlusive disease, the collective long-term experience with traditional operative reconstruction was reviewed. Endarterectomy, currently the procedure of choice for a limited number of patients with disease localized to the aorta and common iliac arteries, has demonstrated 10-year primary patency rates of 48%-77%. By comparison, prosthetic in situ replacement or bypass grafting, commonly performed for more extensive lesions and in the presence of aneurysmal degeneration or total occlusion of the aorta, has yielded 10-year primary patency rates of 62%-79%.

Thiol-containing cross-linking agent with enhanced steric hindrance.

Ricin A chain immunotoxins disulfide cross-linked with conventional, sterically unhindered reagents have unsatisfactorily short circulating life times in vivo. (Acetylthio)succinic anhydride, a thiolating reagent with partial steric hindrance of the sulfur atom, does not remedy this situation. Sulfosuccinimidyl N-[3-(acetylthio)-3-methylbutyryl]-beta- alaninate, a new cross-linker in which the carbon alpha to the sulfur is doubly methylated, creates disulfide bonds 2 orders of magnitude more resistant to reduction than unhindered disulfides.

Transatrial interruption of the inferior vena cava.

Transatrial placement of a Greenfield filter at the time of cardiac surgery was performed on three patients with recent femoral venous thrombosis and unstable angina, and at the time of pulmonary embolectomy on four others. The filter carrier was passed through the right atrial cannulation site under fluoroscopic guidance into the inferior vena cava. A preliminary venacavogram was performed through the carrier or a previously placed angiographic catheter.

Evolution of hook design for fixation of the titanium Greenfield filter.

The titanium Greenfield filter was developed to facilitate operative and percutaneous insertion by a carrier (12F) smaller than that required for the standard stainless steel filter (24F). In preliminary clinical studies however, it proved to have an unacceptable rate of distal slippage and caval wall penetration. Therefore four modifications in hook design and base diameter have been tested in 20 sheep by implantation above and below the renal veins.