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 role of oxidized nicotinamide adenine dinucleotide in fluoride inhibition of active sodium transport in human erythrocytes.

The rate coefficient for (22)Na release from previously labeled human erythrocytes was determined in the presence of 0.1-10 mM sodium fluoride (F). The oxidized nicotinamide adenine dinucleotide (NAD(+)) level at the end of 2 hr of incubation in tris(hydroxymethyl)aminomethane (Tris)-Ringer medium was also measured. Both parameters decreased proportionately as F concentration was raised. Both F-induced changes were immediate and were reversed by 10 mM pyruvate. The decrease in NAD(+) concentration following enolase inhibition by F is attributed to a diminished rate of formation in the reaction catalyzed by lactic dehydrogenase (LDH) with undiminished continued utilization in the reaction catalyzed by glyceraldehyde-3-phosphate dehydrogenase (GAPDH). It is postulated that the NAD(+) lowering limited the GAPDH step, resulting in proportionate decreases in the rates of phosphoglycerate kinase (PGK) and Na,K-dependent adenosine triphosphatase (Na,K-ATPase), a reaction sequence thought to link glycolysis with active Na extrusion. Adding pyruvate with F increased NAD(+) production at the LDH step, thus reactivating GAPDH, PGK, and Na,K-ATPase and leading to the observed restoration of (22)Na release. The results suggest, therefore, that F inhibits active Na transport in intact human erythrocytes indirectly through a lowering of NAD(+), although, direct inhibition of the Na,K-ATPase by F may possibly occur simultaneously.

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.

A double-blind parallel study of acetylcysteine-isoproterenol and saline-isoproterenol in patients with chronic obstructive lung disease.

A double-blind parallel study in patients with asthma compared the safety and efficacy of saline-isoproterenol (SI) and acetylcysteine-isoproterenol (AI), when administered at home as an aerosol, over a one-week period, using a conventional nebulizer compressor. Measurements of pulmonary function revealed statistically significant differences between the two therapies for FEV1 and FVC in favour of AI. In the group treated with AI, the average sputum viscosity after six days of treatment was significantly less than pre-treatment values, or when compared to the results with SI treatment. No serious side-effects were reported during treatment with either therapy. These results indicate that acetylcysteine combined with a bronchodilator, such as isoproterenol, may be safe and of significant value in the treatment of patients with asthma who are also sputum producers.

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.

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.

Physicians view national health insurance: a national study.

Nationally representative samples of senior physicians, interns and residents, and medical students were interviewed during the spring of 1973. The main focus of the present analysis is senior physicians' responses to national health insurance issues. The level of support among physicians is underestimated by physicians themselves. Despite the fact that 56 per cent of the doctors were in favor of "some form of national health insurance," almost three-fourths of the respondents believed that most doctors they knew personally were opposed. More than four-fifths of the physicians believed that NHI was inevitable, and those who saw NHI as inevitable were more likely to favor it. Doctor's views about NHI were closely related to their general political views. In general, attitudes of AMA members and grass-roots state and local medical society leaders were not greatly divergent. In terms of responses to specific components differentiating NHI alternatives, physicians preferred conservative options on how a program was to be financed and administered as well as whether the development of prepaid groups should be encouraged. Support for the liberal alternative was strongest on the question of peer reviews, with 75 per cet in favor of such reviews under a NHI program. Differentiation in the profession is considerable. Main activity, work setting, specialty, percentage of income in salary, geographical location, and career stage all contribute to differing reactions to NHI among physicians.

Allergy and learning disabilities in children.

Allergic children suffering from learning disabilities, hyperactivity, fatigue, incoordination and irritability who were treated by conventional allergic methods showed a marked improvement in ability to learn, reduction of hyperactivity and incoordination, and ability to perform intelligence tests. The objective neurological studies showed no consistent changes as a result of one year of allergy therapy.

Immunoassay of human platelet factor 4(PF4, antiheparin factor) by radial immunodiffusion.

Human platelet factor 4 antigen (PF4 antigen) was measured in platelets and in plasma by means of single radial immunodiffusion. Anti-PF4 antibody obtained in rabbits by injecting highly purified human PF4 was monospecific in double immunodiffusion and in quantitative "rocket" immunoelectrophoresis. A high degree of correlation was observed between the precipitation zones in the radial immunodiffusion method and the amount of purified PF4 (in the range of 0.6 to 50.0 mug per milliliter) or the number of platelets in plasma (in the range of 5 x 10(6) to 1.6 x 10(8) platelets per milliliter applied. The sensitivity of the method was 30 to 125 times higher as compared with clotting assay (antiheparin activity) and the standard error of the method was 2.3 per cent. The method was specific for the antigen present in platelets since human leukocytes and erythrocytes gave negative results. Release of PF4 antigen from washed platelets challenged with thrombin, collagen, ADP, and antigen-antibody complexes was measured by the radial immunodiffusion assay. It usually paralleled the release of 3H-serotonin but PF4 antigen was a more sensitive marker for platelet release reaction. Release of PF4 antigen was usually 2 to 4 times higher than release of the antiheparin activity as measured by clotting assay when both were compared as percentage of total content in platelets. The level of PF4 antigen was determined in platelet-rich plasma (PRP) and platelet-free plasma (PFP) obtained from 12 healthy volunteers. While the mean level of extraplatelet pool of PF4 antigen in PFP was 0.72 +/- 0.92 mug per milliliter, PRP contained 80 +/- 22 mug of PF4 antigen per 10(9) platelets. Addition of thrombin (1 U. per milliliter) liberated all of the PF4 antigen (78 +/- 24 mug) present in PRP but ADP (50 muM) released only 31 +/- 22 mug of PF4 antigen per 10(9) platelets. The presence of heparin did not interfere with the assay of intraplatelet or extraplatelet PF4 by single radial immunodiffusion. The method described represents a simple, sensitive, quantitative, and specific assay for human PF4 antigen possessing antiheparin activity.

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.

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.

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.

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.

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.