Biochemical and biophysical approaches to improving the anticancer effectiveness of Ara-adenine.

Ara-C at very low dosage has been reported to decrease the host toxicity of ara-AMP or ara-A in combination with 2'-deoxycoformycin, a potent adenosine deaminase inhibitor, while increasing the toxicity to intracerebral L1210 leukemia. The possibility of increasing the selectivity of ara-A by prior administration of ara-C is explored. The importance of deoxynucleoside kinases, some of which may be cancer-induced, in obtaining selective anticancer effects is discussed.

Aortoiliac operations and sexual dysfunction.

Male sexual dysfunction after aortoiliac operations can be a distressing complication. Since previous studies dealing with this problem have not excluded other causes of sexual dysfunction, the true incidence of this complication has been difficult to ascertain. We assessed preoperative and postoperative sexual function in a group of patients with no identifiable organic or functional etiology of sexual dysfunction other than aortoiliac operations or arterial occlusive disease.

The influence of glucosidic conformation and charge distribution on activity of adenine nucleosides as presynaptic inhibitors of acetylcholine release.

The electrically stimulated guinea-pig ileum preparation was used to establish the potency of adenosine and a series of nucleoside analogs as presynaptic inhibitors of acetylcholine output and a rank order was obtained. 2-Chloroadenosine was the most potent compound studied (pD2 = 7.74), whereas inosine yielded the lowest measurable efficacy (pD2 = 3.

Toxic effects of juncusol, a marsh plant phenolic extract, on estuarine fish and shrimp.

Juncusol, phenolic compound, was isolated from the black needlerush, Juncus roemerianus. Different concentrations of this extract were tested for toxicity against selected species of estuarine fish and grass shrimp. Juncusol was ten times more toxic to the various species of fish than to grass shrimp.

Ventilation and acid-base equilibrium for upper body and lower body exercise.

The purpose of this study was to compare pulmonary ventilation and blood acid-base responses for upper and lower body exercise at a variety of metabolic intensities. Nine male subjects completed a progressive intensity, discontinuous test for arm crank (AC) and cycle (CY) ergometry. During submaximal exercise, oxygen uptake (VO2), pulmonary ventilation (VE), VE/VO2, alveolar ventilation (VA) and blood lactate (LA) values were found to increase, whereas arterial carbon dioxide partial pressure (PCO2) and arterial pH values were found to decrease with increasing power output for both modes of ergometry.

Evaluation of myocardial performance during wheelchair ergometer exercise.

Since a relatively high incidence of cardiovascular disease is associated with wheelchair confinement, exercise stress testing techniques should be utilized to assess myocardial performance of wheelchair-dependent individuals. Therefore, the purpose of this study was to apply the techniques of impedance cardiography to graded wheelchair-type exercise. For this, 9 wheelchair-dependent volunteers completed a progressive intensity, discontinuous test on a wheelchair ergometer (WERG) at power outputs (PO) of 10, 20, and 30 watts.

Optical activity and electronic absorption spectra of some simple nucleosides related to cytidine and uridine: all-valence-shell molecular orbital calculations.

The circular dichroism and electronic absorption of three simple model systems for cytidine and uridine have been measured to 190 nm. The molecular spectral properties (excitation wavelengths, oscillator strengths, rotational strengths, and polarization directions) and electronic transitional patterns were investigated by using wave functions of the entire nucleoside with the goal of establishing the reliability of the theoretical method. The computed electronic absorption quantities were shown to be in satisfactory agreement with experimental data.

Photosynthesis in Fescue : III. RATES OF ELECTRON TRANSPORT IN A POLYPLOID SERIES OF TALL FESCUE PLANTS.

Photosystem I electron transport activity has been found to be considerably higher in a decaploid tall fescue (Festuca arundinacea Schreb.) genotype as compared to a common hexaploid genotype. The decaploid genotype also displayed a higher photosystem whole chain (Photosystem II plus Photosystem I uncoupled) activity, suggesting a connection between polyploidy and increased electron transport activity.

Influence of respiration on stroke volume determined by impedance cardiography.

The conventional method of calculating stroke volume (SV) with impedance has been to measure changes in thoracic impedance for only those beats of the impedance cardiogram (IC) which cross on a specific baseline. This severely limits the number of usable beats since respiration produces oscillation of the IC around this baseline. This study investigated the influence of respiration on SV calculated independent of the baseline in seven women, 20-44 years old, in each of three postures: seated, supine, and standing.

Hypoxia effects on plasma volume shifts at rest, work, and recovery in supine posture.

The purpose of this study was to determine the effects acute exposure to hypoxia (less than 1.5 h; gas mixture 12.6% O2-87.

Long-term maintenance therapy with prazosin in congestive heart failure.

We evaluated the effects of long-term maintenance therapy with oral prazosin (6-20 mg, mean 14 +/- 2 mg/d) in 14 patients with congestive heart failure. The patients were followed for 6 +/- 1 months. Eleven of the fourteen patients reported subjective improvement.

Photosynthesis in Fescue: I. HIGH RATE OF ELECTRON TRANSPORT AND PHOSPHORYLATION IN CHLOROPLASTS OF HEXAPLOID PLANTS.

Chloroplasts isolated from tall fescue, Festuca arundinacea Schreb., showed high rates of electron transport, comparable to rates observed for spinach chloroplasts.Chloroplasts were well coupled and rates of electron transport from water to methyl viologen (photosystem II and I) were increased two to five times when ADP and inorganic phosphate or methylamine (uncoupler) were added to the reaction mixture.

Salbutamol and cardiac arrhythmias.

A study was carried out in 7 patients with chronic obstructive airways disease to investigate the possibility of serious cardiovascular effects after the intravenous infusion of salbutamol. Patients received salbutamol starting at 5 micrograms/min and increasing gradually to 20 micrograms/min. There results of blood gas analysis showed that all but one of the patients were hypoxic and there was evidence of improved ventilation at the end of the first hour of infusion in most, with a mean reduction of 0.

Leptospira hebdomadis associated with an outbreak of illness in workers on a farm in North Yorkshire.

Four cases of illness attributed to Leptospira hebdomadis occurred on a cattle farm in North Yorkshire. The clinical features were a febrile illness that resembled influenza; in one case there was a lymphocytic meningitis. This infection is probably more common than is recognised at present, and prevention of further cases may be possible if diagnosed promptly.

Effects of toeclip use on metabolic and cardiopulmonary responses to bicycle ergometer exercise.

Toeclips secure the feet to bicycle pedals and are thought to enable greater anticipation of leg musculature in the pedaling motion. To determine the effects of toeclip use on metabolic and cardiopulmonary responses to BERG exercise, 13 female subjects, who had no prior experience with the devices, performed maximal and submaximal work with and without the use of toeclips. Similar oxygen uptake (V02), physical work capacity, pulmonary ventilation (VE), respiratory exchange ratio (R), heart rate (HR), and blood lactate concentration (LA) were found for maximal effort exercise under both conditions.

Physiological adjustments of women to prolonged work during acute hypoxia.

Five women (23-32 yr) performed bicycle work in a hypobaric chamber for 2 h at 41% of their respective altitude maximal oxygen uptakes (VO2) at 758, 586, 523, and 446 Torr barometric pressures (PB). Steady-state VO2 was achieved within 5 min work at all altitudes. Pulmonary ventilation (29.