Variations of accessory thoracic muscles identified in the ethnically diverse whole-body donation population in Northern California

Accessory thoracic muscles in humans are relatively common and it is important to draw awareness to their variable presentations and potential clinical implications owing to their close association with the axilla. Here we report four cases of accessory thoracic muscle variations identified in the ethnically diverse whole- -body donation population in Northern California (4 out of 48 donors, 8.3%). Of these, combined presentations of thoracic accessory muscles were observed in two of the donors, one involving bilateral axillary arches and a pectoralis quartus on the left and the other a unilateral axillary arch on the left and bilateral pairs of pectoral fascicles. In the former, the proximal ends of the left axillary arch and pectoralis quartus joined to form a common aponeurosis which inserted onto the deep tendon of the pectoralis major; in the latter, the pectoral fascicles originated from the surface of the ribs and inserted into the deep surface of the pectoralis major muscle. In the other two donors, unilateral axillary arches were observed. Our observations illustrate that accessory thoracic muscles, in isolated as well as combined forms, are commonplace in the general population. We also describe the proposed embryonic origins of these accessory muscles, which may reflect their frequent occurrence, and potential clinical implications of these muscles, as discussed in literature.

Cautionary note: linewidth effect in dynamic NMR

In using NMR spectroscopy to evaluate the effects of kinetic processes taking place in the solute molecules being studied, one must estimate the inherent width w of each line, which is hidden from view throughout the kinetic thermal region due to the line-width broadening effected by the processes. We have herein built a self-consistent model function w(T) to attempt to evaluate the variation in the Arrhenius activation energy obtained with the model parameters present in w(T). As it turns out, a sizable number of such line-width parameters yields excellent spectral fits, and these lead to a considerable range of possible activation energies.

Dynamic NMR spectroscopy of three 2,2'-dialkyl/aryl-1-picrylhydrazines in liquid solution

We have studied and compared the proton nuclear magnetic resonance spectra of a series of three 2,2'-di(alkyl/aryl)-1-(2,4,6-trinitrophenyl)hydrazines at 500 MHz in liquid toluene-d(8), with a view to learning details of the internal conformation changes taking place, as a function of temperature. Herein "alkyl" denotes 'methyl', and "aryl" denotes 'phenyl'. The synthesis and characterization of 2-phenyl,2'-methyl-1-picrylhydrazine is reported. One goal of the present study was to afford a comparison with the oxidation products, i.e., the three corresponding hydrazyl free radicals - which show striking differences. All the hydrazine molecules in liquid solution occur as interconverting enantiomorphic pairs (atropisomers). Advanced techniques for obtaining the relevant activation energies and pseudo-thermodynamic parameters (Arrhenius and Eyring) have been utilized, and these parameters are listed and discussed. The three hydrazines turn out be very similar with respect to their internal dynamics.

Dynamic NMR spectroscopy of 2,2′-dimethyl-1-picrylhydrazine in various solvents

We have studied the 1H NMR spectra of 2,2′-dimethyl-1-(2,4,6-trinitrophenyl)hydrazine at 300 and 500 MHz in seven liquid solvents, with a view to learning details of the internal conformational changes taking place as a function of temperature and of the solvent. These molecules in liquid solution occur as interconverting enantiomorphic pairs (atropisomers). Advanced techniques for obtaining the correct activation energies and pseudo-thermodynamic parameters have been utilized, and these parameters are listed and discussed. Our results point to a transformation between the pair of atropisomers that is not quite as complicated as one might have encountered in that the solvent does not affect ΔG‡ in any major fashion. Molecular orbital calculations clarified some of the chemical shifts observed for both 1H and 13C. One goal of this study was to enable a detailed comparison with similar results available for 2,2′-diphenyl-1-(2,4,6-trinitrophenyl)hydrazine.Key words: dynamic NMR, dimethylpicrylhydrazine, hindered rotation, atropisomers, activation parameters.

The structure and some molecular properties of acetone-picrylhydrazone

Various physical measurements and quantum-mechanical computations to characterize molecular 2-propanone(2,4,6-trinitrophenyl)hydrazone, alias acetone-picrylhydrazine (AH), are reported, including an X-ray diffraction structural determination, an1H and13C NMR study of its internal hindered reorientation, and a theoretical (SCF-MO) interpretation of these observations. The structure of AH was determined by X-ray crystallography. The space group is Pbar over 1, with a = 10.1768(9) Å, b = 7.7968(18) Å, c = 8.0018(5) Å, α = 92.102(6)°, β = 99.919(7)°, γ = 105.926(6)°, Z = 2, wR2(F2) = 0.1995 based on all 2748 unique reflections. The (picryl) proton NMR thermal work yielded a Gibbs activation energy ΔG‡= 46.9 ± 0.4 kJ mol-1in acetone-d6and 48.1 ± 0.2 kJ mol-1in chloroform-d, whereas13C NMR (two pairs in the picryl ring) yielded 46.6 ± 1.0 and 46.4 ± 1.0 kJ mol-1in acetone-d6. The SCF-MO computations yielded a detailed model of the conformerization path. Various model conformations and tautomers of AH have been considered, as has removal of H+or of H0from its hydrazinic linkage.Key words: dynamic NMR, picrylhydrazone, hindered rotation, activation parameters, SCF-MO model.

Neuroprotective effects of hypothermia and U-78517F in cerebral ischemia are due to reducing oxygen-based free radicals: an electron paramagnetic resonance study with gerbils

Free radicals are implicated as causative agents in various forms of tissue destruction. Considerable circumstantial evidence suggests that oxygen-based free radicals generated as blood flow returns to formerly ischemic brain areas are mainly responsible for the neurodegeneration that follows periods of cerebral ischemia. In general, oxygen-based free radicals are highly reactive and exist for only a brief period of time. This makes the direct measurement of many of these free radicals rather difficult. Much of the current knowledge of free radicals in cerebral ischemia is based on observations of chemical changes brought about by the free radicals rather than on direct observations of the free radicals themselves. Low temperature electron paramagnetic resonance spectroscopy is one method that allows the direct study of free radicals. Compared to samples from sham-operated controls, samples of hippocampus taken from gerbils exposed to 15 min of forebrain ischemia followed by 15 min of reperfusion, frozen in liquid nitrogen less than 20 sec after sacrifice, and scanned by low temperature (100 K) electron paramagnetic resonance, show a significant increase in oxygen-based free radicals and a decrease in carbon-based ubiquinone-like free radicals. The ischemia-induced increase in oxygen-based free radicals is prevented by the intraperitoneal injection of the antioxidant drug U-78517F at the start of reperfusion and by hypothermia. However, neither intervention alters the ischemia-induced reduction in the ubiquinone-like free radicals. This suggests that the neuroprotective actions of hypothermia and U-78517F include a direct reduction in the oxygen-based free radical burden of the post-ischemic tissue.

Free radical formation in autopsy samples of Alzheimer and control cortex

The formation of free radicals in homogenates of frontal cortex from brains taken at autopsy and verified histologically to be from five patients with Alzheimer's disease or from six age matched normal controls, was measured by electron paramagnetic resonance spectroscopy. During incubation at 37 degrees C, the formation of free radicals by Alzheimer's samples was 22% higher (P < 0.05) than controls. Following incubation in the presence of ferrous sulfate (200 microM), samples of Alzheimer's frontal cortex produced nearly 50% more free radicals than did controls (P < 0.01). Although these post mortem in vitro observations are consistent with an increased free radical burden in tissue from patients with Alzheimer's disease, that comparable differences exist in vivo between Alzheimer's patients and non-demented people remains to be demonstrated.

An in vitro EPR study of the free-radical scavenging actions of the lazaroid antioxidants U-74500A and U-78517F

Oxygen-based free radicals have been shown to play a major role in the acute destruction of neurons following cerebral ischemia and may be involved in the chronic neurodegeneration seen in Parkinson's disease, Alzheimer's disease, and other conditions characterized by the progressive death of neurons in the central nervous system. Drugs belonging to a group of antioxidant compounds, collectively known as the lazaroids, have strong neuroprotective effects in experimental models of acute ischemia. However, the specific mechanisms by which these drugs reduce the harmful actions of free radicals have not been established. Using electron paramagnetic resonance (EPR) spectroscopy with spin trapping, we investigated the interaction of U-74500A, a first-generation lazaroid, and U-78517F, a second-generation lazaroid, with two species of oxygen-based free radicals in aqueous solution and with the stable nitrogen-based free radical diphenylpicrylhydrazyl in dimethyl sulfoxide. Superoxide radicals were generated by the action of xanthine oxidase on hypoxanthine. Hydroxyl radicals were generated by the Fenton reaction involving aqueous ferrous iron and hydrogen peroxide. Both lazaroids reduce the EPR signal of all three radicals, but the drugs differ in potency and relative radical selectivity. These observations are consistent with the lazaroids being scavengers of oxygen-based and nitrogen-based free radicals and suggest that the neuroprotective actions of the lazaroids in cerebral ischemia may involve direct interactions of the lazaroids with several different species of free radicals.

Quantitative PET imaging of bone marrow glucose metabolic response to hematopoietic cytokines

To evaluate the effects of hematopoietic cytokines on bone marrow glucose metabolism noninvasively, we studied serial quantitative FDG-PET images in 18 patients with metastatic melanoma and normal bone marrow who were undergoing granulocyte-macrophage colony-stimulating factor (GMCSF) or macrophage colony-stimulating factor (MCSF) administration as an adjunct to chemotherapy.

METHODS

All patients received 14 days of cytokine therapy in three groups: four patients were treated with GMCSF (5 micrograms/kg/d SQ), eight patients were treated with GMCSF (5 micrograms/kg/d SQ) and monoclonal antibody (MAbR24) and six patients were treated with MCSF (80 micrograms/kg/d IVCI) and MAbR24. Dynamic FDG-PET imaging was performed over the lower thoracic or upper lumbar spine at four time points in each patient.

RESULTS

Baseline glucose metabolic rates in the bone marrow of these three groups of patients were similar (5.2 +/- 0.7, 4.4 +/- 0.8 and 4.8 +/- 1.2 micrograms/min/g as mean value and standard deviations, respectively). In both GMCSF and GMCSF + R24 groups, rapid increases in bone marrow glucose metabolic rates were observed during therapy. After GMCSF was stopped, bone marrow glucose metabolic rates rapidly decreased in both groups. The glucose metabolic response in these two groups was not significantly different by pooled t-statistics (p = 0.105). In the MCSF+R24 group, the increase of glucose metabolic rate on Days 3 and 10 was 35% and 31% above baseline on the average, but was not significant.

CONCLUSION

The results support the use of parametric FDG-PET imaging for noninvasive quantitation of bone marrow glucose metabolic changes to hematopoietic cytokines in vivo.

Noninvasive breathing analysis: repetitive chloral hydrate in neonatal guinea pigs

A noninvasive method was used to record neonatal breathing, heart rate (HR), and the electroencephalogram (EEG) in guinea pig pups. Neonates were randomly assigned at birth to chloral hydrate (CH) or placebo (PLA) treatment. Treatments were administered 30 min before each study on days 1, 3, 5, 7, 14, and 21 after birth. Animals were studied while they breathed room air followed by air with 5% CO2 and 30% O2. CH decreased breathing frequency (f) and inspiratory minute volume (VI), but not tidal volume (VT) during the first week (P less than 0.05), and reduced the rate of growth throughout the study (P less than 0.01), whereas breathing of CO2 increased f, VT, VI, HR, and the relative power in the delta frequency band of the EEG. The percent change in VI induced by CO2, however, was not affected by drug treatment. There was a significant day of life effect on all breathing parameters and HR. CH has cumulative effects on breathing and growth that should be considered when it is used as a sedative for repeated neonatal studies in guinea pigs.

In utero cocaine exposure: effect on neonatal breathing in guinea pigs

Cocaine (COC) abuse during pregnancy may be a factor in the development of neonatal breathing abnormalities. To examine this possibility, pregnant Dunkin-Hartley guinea pigs were treated daily with s.c. injections of saline or 2, 6 or 12 mg/kg of COC during the second half of gestation. Treatments were assigned randomly to pregnant dams. Neonatal weight, breathing, ECG and EEG were recorded in unsedated animals using noninvasive techniques at intervals for 3 weeks after birth. Neonatal weight on Day 1 was decreased by exposure to the two highest doses of COC (P less than .05). The effects of drug treatment, day of study and response to inhalation of 5% CO2 were analyzed by repeated measures analysis of variance. A significant drug-, day- and CO2-effect on tidal volume (VT) and inspiratory minute volume (VI) was observed (P less than .01). COC exposure in utero increased the weight-normalized neonatal VT and VI on room air and 5% CO2 during the first 2 weeks of life in the absence of a measurable effect of drug exposure upon breathing frequency, heart rate or EEG power. The increase in VT and VI may be caused by an increase in metabolic rate (hyperpnea) or an alteration of ventilatory control (hyperventilation). Either mechanism could represent functional teratogenesis and either results in a greater ventilatory effort which increases the work of breathing and the consumption of oxygen. An increase in oxygen demand due to an increase in metabolism or an increase in ventilatory effort might compromise some neonates and contribute to an increased incidence of sudden-infant-death.

Ab initio calculations on tetramethoxymethane

Minimal basis set ab initio SCF-MO calculations were performed on the 21-atom system of tetramethoxymethane (tetramethyl orthocarbonate). The geometric configuration of this model was optimized in two conformations, one having quasi-S4 symmetry and the other D2d symmetry. The S4 conformation was found to be 8 kJ mol−1 lower in energy than the D2d conformation, at the STO-3G level. The calculated energy difference is consistent with the recently measured geometric configuration of crystalline tetrabenzyl orthocarbonate. The calculated values of the bond lengths and angles were compared to the results of an electron diffraction study of the methyl species, and agree well with experiment. The theoretical electric dipole moment was calculated to be 0.01 D.

Preparation of 2,2-diaryl-1-picrylhydrazyls using potassium permanganate

Potassium permanganate is used as a reagent for the oxidation of various 2,2-diaryl-1-picrylhydrazines to their corresponding hydrazyls. Thin-layer chromatography indicates complete oxidation of the hydrazine to free radical, unlike the case with PbO2 (the most widely used oxidant for this purpose). Several other advantages over previous oxidants used to produce the hydrazyls are offered.