Ordering decision and clinic cost variation among resident physicians

Physicians vary considerably in the services they order for their patients. We examined ordering variation among 47 resident physicians during 4,991 continuity clinic visits with patients who had specific, chronic medical problems. We ranked the physicians by their average charge per visit and grouped them into three equal categories. High-charge physicians averaged $164 per visit, medium-charge $124 and low-charge $97. In comparing the frequencies with which physicians in each group ordered a wide array of specific laboratory tests, x-ray studies, medications and miscellaneous items, we found that ordering variation among the physician groups was not confined to certain decisions or categories of services. High-charge physicians ordered a little more of nearly every item or service. Although the magnitude of ordering variation for each item was small, the sum over many items was great, suggesting that cost-containment efforts may have to focus on the "little ticket" decision-making style of expensive physicians.

Effect of aminoglycoside-use restrictions on drug cost

The effect on drug costs of restricting aminoglycoside use in a teaching hospital is described. In October 1980, the pharmacy and therapeutics committee deleted tobramycin from the formulary because of its high cost and relative lack of therapeutic advantages compared with gentamicin. Amikacin use was restricted. Concurrently, physicians were instructed in the proper use and dosage of gentamicin via lectures and dosing nomograms provided by the clinical pharmacist. Chart reviews of patients receiving gentamicin showed that the incidence of nephrotoxicity (defined by an increase in serum creatinine of 0.5 mg/dl) was 0%, 4.5%, and 6.5% in fiscal years 1981, 1982, and 1983, respectively. Based on the percentage of total aminoglycoside use represented by tobramycin, gentamicin, and amikacin during the year before implementation of the policy, projected cost savings for three years was more than $42,000. Expensive and improper aminoglycoside use should be a prime target for reduced spending as budgetary constraints in hospitals increase.

Transient vascular compromise of the lunate after fracture-dislocation or dislocation of the carpus

Although classic avascular necrosis of the lunate is rare after fracture-dislocation or dislocation of the carpus, these severe carpal injuries can compromise the vascular supply of the lunate. The lunate thus develops a relative increase in radiodensity. Our finding of an incidence of 12.5%--three of 24 cases--suggests a relatively frequent occurrence. The clinical course was transient with resolution of abnormal radiodensity and subjective findings. Moreover, none of the three cases progressed to classic avascular necrosis of the lunate, Kienböck's disease. The clinician should not confuse this transient vascular compromise of the lunate with Kienböck's disease, but should be aware of the entity and its benign, self-limited course and should treat it expectantly.

Evaluation of the CASPAR alcohol education curriculum

The CASPAR education-prevention program was initiated when experimental results indicated that a 5-hr alcohol education curriculum at a Catholic high school was able to reduce frequent intoxication among teenagers. Attempts to institutionalize such a program in the public schools shows that (1) alcohol education can generate widespread community and school support; (2) workshops can successfully train teachers to adopt a decision-making approach, though close supervision is needed to ensure that this approach is adhered to in classroom teaching; (3) the CASPAR model of alcohol education produces classroom situations conducive to many children feeling free to express alcohol-related concerns; (4) trained teachers can serve as intermediaries between students with alcohol-related concerns and community resources, in particular those resources that are designed to help children from families with alcoholism; (5) the CASPAR curriculum, implemented by trained teachers, produces statistically significant knowledge and attitude gains, whereas alternate programs such as a special-events approach produce smaller knowledge gains and little attitude change; and (6) to a considerable extent, knowledge and attitude gains persist over time, although retention is greater on knowledge items and among older students. The results suggest that there may be a behavioral impact of instruction in the form of reduced alcohol misuse among teenagers, although if there is, it requires intensive and repeated exposure and can be demonstrated in these data only among younger students while they remain in junior high school. Although such results may be viewed as less supportive than the original experiment with which this work began, they do suggest that alcohol education remains an effective prevention strategy.

Regioselectivity in the cytochromes P-450: control by protein constraints and by chemical reactivities

Three alicyclic compounds (D-camphor, adamantanone, adamantane) were found to be hydroxylated by the cytochrome P-450 isoenzymes P-450cam and P-450LM2. With P-450cam as the catalyst only one product was formed from each of the substrates: 5-exohydroxycamphor, 5-hydroxyadamantanone, and 1-adamantanol. With P-450LM2 as the catalyst, two or more isomeric products were formed from each substrate: 3-endo-, 5-exo-, and 5-endo-hydroxycamphor; 4-anti- and 5-hydroxyadamantanone; and 1- and 2- adamantanol. The products from P-450cam hydroxylations were found to be isosteric with one another, suggesting that each of them was attacked at a topologically congruent position within a rigid enzyme-substrate complex. The distribution of products from P-450LM2 hydroxylations, on the other hand, were similar to the distributions expected during solution-phase hydroxylations. Thus, it would appear that the complex which P-450LM2 forms with its substrate allows considerable movement of the substrate molecule, such that most of the hydrogens in the substrate are exposed to the enzymatic hydrogen abstractor. Under these conditions, the distribution of products more nearly reflects the rank order of chemical reactivities of the various hydroxylatable positions, with only a moderate protein-based steric constraint being expressed. These suggestions were also evident in the tightness of binding of the substrates to the two enzymes and in the magnitude of coupling between the substrate binding and the spin-state equilibria. Thus, the product from P-450cam-catalyzed hydroxylation may be predicted by a consideration of the relation of the topology of the prospective substrate to that of D-camphor. The products from P-450LM2-catalyzed hydroxylations, on the other hand, may be approximately predicted from the chemical reactivities of the various abstractable hydrogens in the prospective substrate.

2,3-dihydro-4H-1-benzopyran-4-one O-carbamoyloximes, a series of gastric antisecretory agents

A series of 2,3-dihydro-4H-1-benzopyran-4-one O-carbamoyloximes were synthesized and evaluated for gastric antisecretory activity in a pylorus-ligated rat model. Various substituents in the 6-position did not afford any compounds more active than I.

Competing modes of peroxyacid flux through cytochrome P-450

In the presence of peroxyphenylacetic acid and a hydroxylatable substrate, cytochrome P-450LM2 catalyzes two reactions which proceed concurrently, decarboxylation of the peroxyacid and hydroxylation of substrate. While the first process is definitely the result of homolytic cleavage of the peroxide O--O bond, the second may involve a different mechanistic pathway. We have undertaken to determine the relationship between these two processes through a kinetic analysis of the system. Seven different mechanistic schemes are advanced to account for the two processes. The two reactions were found to have different apparent Michaelis constants for peroxyacid and different inhibition constants for cyanide. Since the ratio of the two products is saturable at high substrate concentrations, the decarboxylation reaction can proceed from both substrate-bound and substrate-free enzyme. By appropriate manipulation of the rate equations it is possible to derive expressions for the ratio of hydrogen abstraction rate constants for a series of p-substituted toluene substrates compared to toluene. The nature of the correlation of these expressions with delta in a Hammett plot allowed some of the schemes to be eliminated. After consideration of all the data, we concluded that the processes of decarboxylation and hydroxylation occur in separate pathways and do not involve any common intermediate beyond the ferric resting state of the enzyme.

Functional differences between peroxidase compound I and the cytochrome P-450 reactive oxygen intermediate

A series of seven hemeproteins, cytochromes P-450LM2, P-450LM4, and P-420LM2, horseradish peroxidase, chloroperoxidase, catalase, and metmyoglobin, as well as hemin were tested for their ability to catalyze a set of five oxidative reactions. These reactions were a typical peroxidative reaction (oxidation of pyrogallol to purpurogallin) and three characteristic P-450 reactions (aliphatic hydroxylation, aromatic hydroxylation, and olefinic epoxidation). In addition, the ability to decarboxylate a peroxyacid was measured. All hemeproteins were able to carry out peroxidation, but three (horseradish peroxidase, chloroperoxidase, and catalase) were much better catalysts than the others. Only the P-450 enzymes were competent catalysts for the hydroxylation and epoxidation reactions. Furthermore, the decarboxylation reaction was strictly limited to the P-450 enzymes, establishing it as a new, unique P-450 activity. Since the decarboxylation of peroxyacids is diagnostic of peroxide homolysis, these results indicate a fundamentally different manner of processing of peroxides by cytochrome P-450 than by the peroxidases. Thus, the possibility of close similarity of reactive oxygen intermediates in the two series is called into question.

Comparison of family medicine and internal medicine: charges for continuing ambulatory care

The authors compared charges for ambulatory and continuing patient care prescribed by residents in internal medicine and family medicine. An analysis of covariance showed that the charges per encounter in internal medicine were $38.83 greater than charges in family medicine after accounting for differences such as patient age, diagnosis, and severity of condition. However, family practitioners scheduled patient encounters more frequently. The median number of days between encounters was 30 for family medicine and 60 for internal medicine. The duration of medical care for each patient (up to 18 months was possible) and the summation of encounter charges over that duration of medical care were evaluated. Because only two out of eight duration-of-medical-care categories were significantly less in family medicine, the differences in charges between the specialties essentially disappeared. Comparative studies which consider only charges per encounter potentially have a large bias.

Bony ingrowth fixation of the acetabular component in canine hip joint arthroplasty

Five mature dogs were studied five to eight months after insertion of a newly designed acetabular component that eliminates the use of bone cement in total hip arthroplasty (THA). The component was hemispheric, with a layer of porous metal on its outside surface. It initially was fixed to the innominate bone by screws passed through projections from the edge of the metal substrate. When the dogs were killed five or eight months after implantation, all components were fixed rigidly to the bone. Bony ingrowth covered an average of 53% of the porous surface of the implant, penetrating three layers of balls.

Impact of a cost-containment educational program on housestaff ambulatory clinic charges

A cost-containment project was established to determine if a broad educational program that coupled clinical logic with feedback of charges to internal medicine residents in an ambulatory clinic setting could alter behavior. The project was evaluated by comparing charge data from a preintervention comparison year with charge data from the intervention year. Decreases in charges for laboratory procedures occurred in six of the seven diagnostic categories during intervention and were significant (t-test) for four categories. Regression analysis evaluated the influence of the intervention and 12 other variables on charges and demonstrated that the intervention was associated with a mean reduction of lab charges of $ 6.30 (p less than 0.0001) and a mean reduction of total encounter charges of $ 10.36 (p less than 0.01). We conclude that our educational program resulted in a decrease in mean laboratory changes and total charges for ambulatory encounters.

Evidence for a second microsomal trans-2-enoyl coenzyme A reductase in rat liver. NADPH-specific short chain reductase

Evidence for the existence of a previously unknown rat hepatic microsomal reductase, short chain trans-2-enoyl-CoA reductase (SC reductase) is presented. This reductase has a specific requirement for NADPH, is unable to utilize NADH, and catalyzes the conversion of crotonyl-CoA and trans-2-hexenoyl-CoA to butyric acid and hexenoic acid at a rate of 5 and 65 nmol per min per mg of microsomal protein, respectively. Highly purified NADPH cytochrome P-450 reductase incorporated into liposomes prepared from dilauroyl phosphatidylcholine in the presence or absence of cytochrome P-450 possesses no SC reductase activity. These liposomal preparations did, however, catalyze mixed function oxidations of benzphetamine and testosterone. Rabbit antibody to rat liver NADPH cytochrome P-450 reductase had little to no effect on the conversion of crotonyl-CoA and trans-2-hexenoyl-CoA, suggesting that the SC reductase accepts reducing equivalents directly from NADPH. When acetoacetyl-CoA was incubated with hepatic microsomes and either NADH or NADPH, no formation of butyrate was detected; however, when both cofactors were present, a rate of formation of 3 nmol of butyrate was determined per min per mg of microsomal protein. These results suggest the presence of a previously unknown short chain beta-ketoreductase which catalyzes the reduction of short chain beta-keto acids, only in the presence of NADH. Our results also indicate that the electrons from NADH to the beta-ketoreductase bypass cytochrome b5. The physiological significance is discussed in terms of lipogenesis and ketone body utilization by the liver.

Evaluation of educational methods in a comprehensive cost-containment project in ambulatory care

The cost of medical care in the United States is a matter of great concern to many health policy makers and physicians as well as to the seekers of care. At the University of New Mexico, a comprehensive cost-containment education program was devised and put into effect with residents from three primary care disciplines. In addition to documenting the effectiveness of the educational package in reducing patients charges, we asked house staff to state which parts of the package were of most use. Wall posters displaying charges for commonly ordered tests, procedures, and prescription items and the distribution of sample bills for patients seen by the individual resident were rated most highly. A test of knowledge of charges to patients did not show resident improvement after education. Cost-containment education can be effective in reducing patient charges, even if physicians do not internalize the actual charge data. We recommend the inclusion of cost-containment education in all primary care training programs, as these physicians play such an important role in the generation of patient charges.

Acute pulmonary edema with respiratory failure--newer concepts in therapy

The treatment for pulmonary edema with the adult respiratory distress syndrome is aimed at the early supportive management of hypovolemic shock. The addition of massive corticosteroid dosage, Methylprednisolone Succinate, of 30 mg/kg body wt/dose ever six hours for a 24-48 hour period has been shown in our investigation to be efficacious, particularly in the traumatic and septic shock groups of patients but not in patients with multiple system diseases. Ventilator care utilizing constant positive pressure breathing or constant positive airway pressure in the patient who has spontaneous respirations is of prime importance. The recent utilization of hyperalimentation has also been very effective as an adjunctive therapy and should be used in the management of this problem in the future in conjunction with the steroids. Hemodynamic monitoring employing the specific parameters as delineated in our discussion are all major steps that should be pursued on a routine basis in the vast majority of these patients. The most important factor in the prognosis of this condition is the severity and number of injuries that have occurred at the time of the initial trauma. Other factors affecting the outcome are age, prolonged shock, associated degenerative cardiovascular disease, metabolic imbalance, severe multiple system involvement, and sepsis. We now feel that the utilization of massive corticosteroid therapy is indicated with the first earliest clinical signs of this condition in order to attempt to prevent complications and probably improve survival rate.

Socket fixation using a metal-backed acetabular component for total hip replacement. A minimum five-year follow-up

We did a follow-up study on fifty-three total hip-replacement procedures in forty-seven patients in whom a metal-backed acetabular component was used. The minimum follow-up was five years (average, six and one-half years). These relatively young patients ranged in age from seventeen to seventy-six years old (average, forty-one years old). Excluding one septic hip and one traumatic dislocation of the acetabular component, three sockets became loose in the remaining fifty-one hips. The results in thirty-four patients who were forty-five years old or younger were compared with those in a group of patients of similar age, reported by Dorr and Takei, in whom sockets without metal backing were used. Thirteen of the forty-three non-metal-backed sockets in their patients became loose or had a continuous radiolucent line at least two centimeters thick around the entire circumference of the cement on an anteroposterior radiograph, which they referred to as impending failure. In comparison, the three loose acetabular components in our thirty-four patients comprised a statistically significant reduction (p less than 0.05). No acetabular components in our series showed evidence of impending failure. We and others have reported finite-element analyses showing that a metal backing on the acetabular component reduces peak stresses in the bone, cement, and polyethylene. These analytical data are now supported by the clinical data reported here; that is, the metal backing of the acetabular component enhanced the duration of cement fixation.

Heme ligand replacement reactions of cytochrome P-450. Characterization of the bonding atom of the axial ligand trans to thiolate as oxygen

Evidence of several types has accumulated that cytochrome P-450 has a thiolate anion as one of the axial ligands to heme (the fifth ligand). On the other hand, there is as yet no general agreement on the nature of the axial ligand trans to thiolate (the sixth ligand), although nitrogen and oxygen have been proposed. To resolve the controversy, the ligand exchange reactions of cytochrome P-450 were investigated by the use of optical spectroscopy. Two isozymes of rabbit liver microsomal cytochrome P-450 were examined: the isozyme induced by phenobarbital (P-450LM2), which has a sixth ligand and is low spin and the isozyme induced by 5,6-benzoflavone (P-450LM4), which is without a sixth ligand and is high spin. A series of artificial ligands was chosen to model the coordination of each of the potential native ligands, including water and certain amino acid residues. When the artificial ligand coordinated through an oxygen atom, the spectrum of pentacoordinate P-450LM4 changed to one closely resembling that of native, hexacoordinate P-450LM2. The spectrum of P-450LM2 was unchanged in the presence of oxygen-coordinating ligands. However, when artificial ligands which coordinate through nitrogen or sulfur were added to either P-450LM2 or P-450LM4, the induced spectra did not resemble the native spectrum and, in fact, were distinctive and characteristic of the particular ligand type. With three of the artificial ligands, 1-butanol, 1-benzylimidazole, and diethylphenylphosphine, the binding was found to be reversible by dilution, ultrafiltration, or gel filtration. The binding of 1-pentanol and 1-benzylimidazole was competitive, as expected for heme ligands, and the number of 1-benzylimidazole binding sites per molecule of P-450LM2 was estimated as 1.1. These results provide strong evidence that the native sixth ligand in P-450LM2 is oxygen rather than nitrogen.

The hip-shelf procedure. A long-term evaluation

Renewed interest in the hip-shelf procedure as a solution to the dysplastic acetabulum in the older child stimulated an evaluation of the long-term results in an effort to clarify the role of this procedure. Only patients with a minimum of ten years of follow-up were evaluated in the study. The average follow-up for the entire series of twenty-nine hips in twenty-seven patients was twenty-two years and ten months. At evaluation, pain was present in fifteen hips, a limp was present in twenty-five, and degenerative changes were present in twenty hips. Complications occurred in twenty-one hips and additional operative procedures were required in fourteen hips. Twenty-one of the twenty-nine hips were evaluated by us, with an average follow-up of twenty-five years and eight months. One hip was rated as excellent; eight, as satisfactory; and twelve, as poor. Although the hip-shelf procedure has been described as a safe, conservative, and reliable approach to the problem of a dysplastic acetabulum, our long-term results suggest a more cautious view of the use of this procedure. We recommend consideration of other stabilizing procedures for the dysplastic acetabulum.