Prospective study of risk factors for suicidal behavior in individuals with anxiety disorders.

BACKGROUND: Anxiety disorders are very common and increase risk for suicide attempts. Little is known about predictors of increased risk specifically among individuals with anxiety disorders. The purpose of this study was to investigate whether specific anxiety disorders and other co-morbid psychiatric disorders, physical health, or work or social functioning increased the future likelihood of a suicide attempts among individuals with anxiety disorders. Method In this prospective study, 676 individuals with an anxiety disorder were followed for an average of 12 years. RESULTS: As hypothesized, we found that post-traumatic stress disorder, major depressive disorder (MDD), intermittent depressive disorder (IDD), epilepsy, pain, and poor work and social functioning all predicted a shorter time to a suicide attempt in univariate analyses. In multivariate analyses, baseline MDD and IDD were independent predictors of time to suicide attempt, even when controlling for a past history of suicide attempt. No specific anxiety disorder was an independent predictor of time to attempt in this anxiety-disordered sample. Adding baseline physical health variables and social functioning did not improve the ability of the model to predict time to suicide attempt. CONCLUSIONS: Mood disorders and past history of suicide attempts are the most powerful predictors of a future suicide attempt in this sample of individuals, all of whom have an anxiety disorder.

The effects of whirlpools baths in labor: a randomized, controlled trial.

BACKGROUND: Showers and tubs in labor were not generally used in our center. When three whirlpool baths (Jacuzzis) were ordered as part of our renovations, a randomized, controlled trial was initiated to explore their effects on narcotic and epidural requirements. METHODS: This study employed an intent-to-treat design, and the sample size was estimated to account for the fact that some women would be unable to use the tub. The experimental group of 393 women was offered the tub during labor and the control group of 392 women received conventional care. RESULTS: No births occurred in the tub. The tub group required fewer pharmacologic agents than controls (66% vs 59%, p = 0.06), experienced fewer deliveries by forceps and vacuum (p = 0.019), and were more likely to have an intact perineum than the standard-care group (p = 0.019). Labor was longer for the tub group (p = 0.003), who coincidentally were more primiparous and in earlier labor on admission. No differences were noted in the low rates of maternal and newborn signs of infection in women with ruptured membranes. A subset of mothers expressed satisfaction with the tub experience and labor support. The cesarean rate among both groups was lower (8.9%) than our overall rate (16.6%) during the study period. CONCLUSIONS: Whirlpool baths in labor have positive effects on analgesia requirements, instrumentation rates, condition of the perineum, and personal satisfaction. Further study is being planned.

Physician impact on hospital admission and on mortality rates in the Medicare population.

OBJECTIVE: We assess the effect of variations in the supply and specialty distribution of physicians on admission rates for ambulatory care-sensitive conditions (ACS) and for all causes, and on mortality rates among Medicare beneficiaries of various health care service areas (HCSA). DATA SOURCES: For the Medicare beneficiaries, sources were the Health Care Financing Administration's 1992 enrollment and impatient (Part A) files for a 5 percent sample of that population; for the overall populations and for the medical resources of the HCSAs, the Area Resource File. STUDY DESIGN: This observational, cross-sectional study employed multiple linear regression to assess the influence of population characteristics and of the supply of physicians on hospital admissions, and Poisson regression in the analysis of the factors that affect mortality. PRINCIPAL FINDINGS: Physician supply levels vary nearly fourfold or more when comparing the top and bottom deciles of the HCSAs, Medicare admissions for ACS conditions vary about threefold, and admission rates for all causes and mortality rates vary about 1.5-fold. Physician supply levels and distributions have very little influence on ACS admission rates, and even less on the admissions for all causes and on mortality, except in HCSAs with very low physician supply levels (one-fourth the national average or less). However, these HCSAs account for only about 1 percent of the U.S. population. CONCLUSIONS: Physician supply levels and the proportions of specialists and generalists have negligible effects on health status as measured by mortality rates and by rates of admission for all causes and for conditions presumed to be sensitive to the adequacy of ambulatory care. Reductions in admissions for such conditions are not likely to be achieved through broadening of insurance to levels that exist under Medicare, nor through increases in the supply of physicians, nor, conversely, through a reduction in any presumed oversupply of physicians.

Kinetics of dissolution of gaseous halothane in Krebs-Ringer's solution.

The responses of biological tissues to volatile anaesthetics are commonly studied by incubating specimens in a bath containing dissolved anaesthetic. One accepted technique is to bubble an anaesthetic gas into several incubation chambers simultaneously. To assess the validity of this technique in producing dissolved anaesthetic (the biologically active form) at equal rates among the several chambers, we determined the kinetics of dissolution of halothane gas in three tissue incubation chambers containing Krebs-Ringer's solution. We found that (1) the dissolution kinetics were first-order in all three chambers; (2) the rate of halothane dissolution depended on the gas bubbling rate; (3) even with the same bubbling rates, chamber shapes and chamber volumes, the dissolution rates for the three chambers were not equal, suggesting that dissolution rate depended on small differences in chamber geometry; (4) the dissolution rates could be made equal by adjusting chamber bubbling rates according to calculations involving the first-order rate equation; and (5) the maximum coefficient of variation of dissolved halothane concentration was 9% at 63% approach to equilibrium and 3% at equilibrium.

Use of acetylcysteine in bronchial asthma--another look.

Acetylcysteine is a potent mucolytic agent. When utilized as a 10% solution with a bronchodilator by pressure machine, clearance of tracheobronchial secretions can be achieved in asthmatic subjects without inducing bronchospasm.

Treatment of a patient with chronic bronchial asthma with many bronchoscopies and lavages using acetylcysteine: a case report.

This Case Report is that of a young woman followed for 21 years, whose life was saved repeatedly by bronchoscopy and lavage to remove mucous plugs and casts from the tracheobronchial tree. In 1982, after again having a respiratory crisis and not having a bronchoscopy and lavage, she died. The pathology revealed a thickened hyalinized basement membrane and numerous mucous plugs filling the larger bronchi and bronchioles.

Interrod forces in aqueous gels of tobacco mosaic virus.

The lateral separation of virus rod particles of tobacco mosaic virus has been studied as a function of externally applied osmotic pressure using an osmotic stress technique. The results have been used to test the assumption that lattice equilibrium in such gels results from a balance between repulsive (electrostatic) and attractive (van der Waals and osmotic) forces. Results have been obtained at different ionic strengths (0.001 to 1.0 M) and pH's (5.0 to 7.2) and compared with calculated curves for electrostatic nad van der Waals pressure. Under all conditions studied, interrod spacing decreased with increasing applied pressure, the spacings being smaller at higher ionic strengths. Only small differences were seen when the pH was changed. At ionic strengths near 0.1 M, agreement between theory and experiment is good, but the theory appears to underestimate electrostatic forces at high ionic strengths and to underestimate attractive forces at large interrod spacings (low ionic strengths). It is concluded that an electrostatic-van der Waals force balance can explain stability in tobacco mosaic virus gels near physiological conditions and can provide a good first approximation elsewhere.

Status Asthmaticus: use of acetylcysteine during bronchoscopy and lavage to remove mucous plugs.

Three patients suffering from severe, chronic, bronchial asthma underwent bronchoscopy and lavage, using in the irrigant fluid acetylcysteine, isoetharine and Solu-Medrol. All patients had a large amount of thick mucus in the tracheobronchial tree which was removed during the lavage. Following the lavage, all three patients were easily treated with conventional allergic measures and were able to lead normal lives, which they could not do before. A discussion of the precautions to be taken by the medical-surgical team in charge of a patient undergoing bronchoscopy and lavage is made. These conclusions were based on the results of two previous reports by the authors in addition to the present communication.

Effects of monovalent ion binding and screening on measured electrostatic forces between charged phospholipid bilayers.

In an effort to determine the role that monovalent ions play in the modification of intermembrane forces, we have measured these forces between charged phospholipid bilayers in monovalent ionic solutions. The osmotic stress technique allowed the net electrostatic pressure between the bilayers to be measured while their separation was concurrently determined by x-ray diffraction. Taken together, these measurements yielded electrostatic pressure as a function of bilayer separation. We have related measured pressures to the bilayer surface charge density and surface potential through an exact solution of the full nonlinear Poisson-Boltzmann equation for this system. Quantitative differences in bilayer separation amongst monovalent alkali metal cations indicated differential binding of these to phosphatidylglycerol (PG), phosphatidylserine (PS), and phosphatidic acid (PA); binding affinity series were determined for Li+, Na+, K+, Cs+, and TMA+ ions to these lipids. The anions Cl-, Br-, I-, and CH3COO- were found to have no differential effect on the repulsive forces between PS bilayers. Debye lengths for the electric double layer estimated from the slopes of the experimental pressure curves were consistently longer than predicted on the basis of classic Gouy-Chapman theory. Estimates of the van der Waals Hamaker coefficient between bilayers of PS and PG in salt solution were found to be weaker than between phosphatidylcholine bilayers in pure water, a difference possibly due to electromagnetic retardation and ionic screening.

A thermal transition of passive calcium efflux in fragmented sarcoplasmic reticulum.

The temperature dependence of passive Ca2+ efflux from skeletal muscle fragmented sarcoplasmic reticulum (FSR) was studied by dilution of a suspension of the vesicles into which 1 mM (CaCl2 + 45Ca) had been passively incorporated by overnight incubation at 3 degrees. It was found that in the presence of 5 mM Mg2+, Ca2+ efflux could be resolved into two simultaneous first-order processes between 5 degrees and 35 degrees, but only a single first-order process appeared between 37 degrees and 55 degrees. Two independent functional transitions were found at 30 degrees, indicating an abrupt membrane molecular reorganization at that temperature: (1) The two components of Ca2+ efflux at 5 degrees--35 degrees contributed equally to the total observed initial efflux at temperatures up to 30 degrees. Between 30 degrees and 35 degrees, the relative contribution of the fast component progressively diminished until, by 37 degrees, only the slow component remained. (2) The slow component, which persisted throughout the entire temperature range 5 degrees--55 degrees, exhibited a break in its Arrhenius plot at 30 degrees--32 degrees. Elevation of internal Ca2+ concentration to 10 mM failed either to produce saturation kinetics of efflux or appreciably change its first-order rate constant. Omitting Mg2+ in the low temperature range accelerated Ca2+ efflux about 20-fold and eliminated the fast component, whereas including Ca2+ in the external medium in the high temperature range retarded Ca2+ efflux by about the same factor and generated a fast component. Omitting Mg2+ in the high-temperature range, however, had little effect on Ca2+ efflux. The failure of external divalent cation to stimulate Ca2+ efflux thus precludes an obligatory carrier-mediated exchange mechanism. Furthermore, participation of the catalytic turnover function of the Ca2+-ATPase molecule in Ca2+ efflux was unlikely because (1) the 30 degrees transition temperature for efflux did not coincide with those previously determined for active Ca2+ uptake, ATPase activity, and reversal of the Ca2+ pump, and (2) above the transition temperature, the activation enthalpy and activation entropy increased for efflux but decreased for both active Ca2+ uptake and ATPase activity. Ca2+ efflux therefore probably involved simple diffusion through a membrane pore (Ca2+ "leak"). By comparison to the results of others using artificial and biological membranes, the effect of external divalent cation to produce a fast component of Ca2+ efflux from FSR is tentatively attributed to the formation of aggregates of SR vesicles.