Probing Cu(I) in homogeneous catalysis using high-energy-resolution fluorescence-detected X-ray absorption spectroscopy.

Metal-to-ligand charge transfer excitations in Cu(I) X-ray absorption spectra are introduced as spectroscopic handles for the characterization of species in homogeneous catalytic reaction mixtures. Analysis is supported by correlation of a spectral library to calculations and to complementary spectroscopic parameters.

Stabilizing coordinated radicals via metal-ligand covalency: a structural, spectroscopic, and theoretical investigation of group 9 tris(dithiolene) complexes.

Proper assignment of redox loci in coordination complexes with redox-active ligands to either the metal or the ligand is essential for rationalization of their chemical reactivity. However, the high covalency endemic to complexes of late, third-row transition metals complicates such assignments. Herein, we systematically explore the redox behavior of a series of group 9 tris(dithiolene) complexes, [M(mnt)3]3­ (M = Ir, Rh, Co; mnt = maleonitriledithiolate). The Ir species described comprise the first examples of homoleptic Ir dithiolene complexes. The enhanced metal­ligand covalency of the Ir­S interaction leads to remarkable reactivity of [Ir(mnt)3]3­ and stabilization of mononuclear [Ir(mnt)3]2­ complex ions as well as dimerized versions featuring weak, covalent, intermolecular S­S bonds. The dianionic Rh and Co analogues are, in contrast, highly unstable, resulting in the rapid formation of [Rh2(mnt)5]4­ and [Co(mnt)2]22­, respectively. The synthesized complexes were studied by single-crystal X-ray diffraction, X-ray absorption spectroscopy, optical spectroscopy, magnetometry, density functional theory, and spectroscopy-oriented configuration interaction calculations. Spectroscopic and theoretical analyses suggest that the stability of [Ir(mnt)3]2­ may be attributed to dilution of ligand radical character by a high degree of Ir 5d character in the singly occupied molecular orbital.

Atropine absorption after intramuscular administration with 2-pralidoxime chloride by two automatic injector devices.

Compared with manual intramuscular injection, automatic injector delivery substantially enhances drug absorption rate. We examined the effect of two types of automatic injector delivery of two drugs which are components of the standard antidote to anticholinesterase poisoning and which have been previously shown to have a reduced absorption rate when mixed together in a manual injection. In crossover experiments one week apart, 20 nonsmoking healthy young male humans (ages 20-30) were studied after citrated atropine (6.9 mumol/0.7 mL) and pralidoxime chloride (3.5 mmol/2.0 mL; PAMCL) were injected sequentially into a single intramuscular site by either a multichambered autoinjector or a device which delivers the drugs into two separate intramuscular sites (MARK I). Atropine absorption was assessed by the appearance of atropine in the serum and by changes in heart rate, salivary secretion, pupil diameters, and near vision accommodation. Atropine absorption was significantly greater in the first 30 min following injection with the MARK I. The results of this study suggest that: (1) the MARK I device produces a faster absorption of atropine, probably through some combination of its broader dispersal of atropine in the muscle site and its separation of atropine from the PAMCL; (2) salivary secretion may be the most convenient and sensitive marker of atropine action; and (3) the 6.9- mumol (2-mg) dose of atropine delivered by either autoinjector gives near maximal antisialogogue activity in normal male humans.

Tourniquet hemostasis. A clinical study.

A clinical study was undertaken to evaluate the pneumatic tourniquet setting required for adequate hemostasis in extremity surgery. After induction of anesthesia, the pneumatic tourniquet pressure at which the peripheral pulse disappeared was determined using a Doppler stethoscope. For upper-extremity procedures 50 mm Hg was added to this setting to allow for collateral circulation and blood pressure changes. An average pressure of 189.9 +/- 24.1 mm Hg was used for the upper-extremity group (44 patients), and an average of 231.0 +/- 26.5 mm Hg was used for the lower-extremity group (40 patients). Maximum pressures utilized were 255 mm Hg in the upper extremity and 305 mm Hg in the lower extremity. This simple, noninvasive technique uses tourniquet pressure settings well below those recommended in standard reference texts without sacrificing the adequacy of hemostasis to obtain a "bloodless field."

Seminal fluid androgen binding protein.

The following study was undertaken to determine the presence of an androgen binding protein (ABP) in the ejaculate. Seminal fluid was obtained from ten fertile subjects. Sperm counts ranged from 20 x 106/cc to 80 x 106/cc. Each sample was preincubated with tritiated dihydrotestosterone (DHT) and examined by polyacrylamide gel electrophoresis (PAGE). Second, after preincubation of the samples with tritiated DHT, the samples were mixed with Concanavalin-A bound to sepharose-D (C-S) and the supernate separated and counted. Finally, saturation analysis of the samples using dextran-coated charcoal for separation and counted. Finally, saturation analysis of the samples using dextran-coated charcoal for separation was performed and Scatchard analysis was used to determine the concentration of ABP present. PAGE demonstrated ABP in seven of ten samples studied. The bound counts of DHT were removed by C-S. The concentrations of ABP ranged from 0.132 to 0.468 nanomoles ABP/dl semen. These data indicate there is an ABP in seminal fluid similar to that from the Sertoli cell.

Seminal characteristics in the presence of a varicocele as compared with those of expectant fathers and prevasectomy men.

One hundred and thirty-one semen analyses were performed on men found to have a varicocele on a routine physical examination. The seminal characteristics of these men were contrasted with those of 87 men who were desirous of having a vasectomy and with those of 25 expectant fathers. No significant differences were found in the mean sperm density in these three groups of men. However, it was noted that a greater percentage of men with a varicocele had a sperm count of 20 million or less as compared with the control groups. It was also found that a greater percentage of the men with either a large or medium-sized varicocele had a sperm count of 20 million or less than those with a small varicocele. There was no significant difference in the percentage of oval forms, motility, or tapered forms in the three groups of men with a varicocele as compared with expectant fathers and men desirous of a vasectomy.

PIP: 131 semen analyses were performed on men found to have a varicocele on routine physical examination. The seminal characteristics of these men were contrasted with those of 87 men who desired a vasectomy and with those of 25 expectant fathers. No significant differences were found in the mean sperm density in these 3 groups of men. However, it was noted that a greater % of men with a varicocele had a sperm count of 20 million or less as compared with the control groups. It was also found that a greater % of the men with either a large or medium-sized varicocele had a sperm count of 20 million or less than with a small varicocele. There was no significant difference in the % of oval forms, motility, or tapered forms in the 3 groups of men with a varicocele as compared with expectant fathers and men desiring a vasectomy.