THE PSYCHOLOGICAL IMPACT OF HIP ARTHROPLASTY

The impact of total hip arthroplasty on psychological functioning was examined in 51 patients; 25 females and 26 males with a mean age of 65 years (range 42–81 years). Assessments of psychological well-being and distress were made with the Mental Health Inventory. Life satisfaction, self-rated health, and pain ratings were also obtained. Assessments were made prior to surgery, immediately after surgery, and at a 2 month follow-up. The operation produced significant improvements in psychological well-being (P < 0.001), psychological distress (P < 0.001). life satisfaction (P < 0.01), self-rated health (P < 0.001), and pain (P < 0.001). It is concluded that the changes in medical and functional status following hip arthroplasty documented in previous research are accompanied by substantial improvements in psychological state, and that the inclusion of psychological factors in hip arthroplasty research will provide a more comprehensive assessment of outcome.     

Three-dimensional color Doppler sonography and uterine artery arteriography of fibroids: assessment of changes in vascularity before and after embolization.

OBJECTIVE: To assess the accuracy of three-dimensional color Doppler sonography and uterine artery arteriography in depicting changes in fibroid vascularity before and after embolization. METHODS: Preembolization and postembolization three-dimensional color Doppler sonography and selective uterine artery arteriography were retrospectively compared in 15 patients who underwent uterine artery embolization for treatment of symptomatic fibroids. Three-dimensional color Doppler sonography was performed by using a scanner with color power angiographic imaging capability. Vascularity was quantified by using an estimation of power-weighted pixel density as described by our group in previously published studies. Uterine artery arteriography was performed by using a standard selective microcatheter embolization technique. For purposes of comparison, fibroids were classified as either hypervascular or hypovascular relative to myometrial vascularity before and minutes to several hours after uterine artery embolization. Changes in fibroid vascularity (i.e., from hypervascular to hypovascular) as depicted by three-dimensional color Doppler sonography were compared with those shown on uterine artery arteriography and classified as being in agreement or disagreement. RESULTS: In 13 (87%) of 15 patients there was agreement; in 2 (13%) of 15 there was disagreement. In both cases of disagreement, three-dimensional color Doppler sonography showed collateral flow not depicted by uterine artery arteriography The mean reduction in quantitated vascularity after uterine artery embolization was 44% (range, 19%-78%). CONCLUSIONS: Three-dimensional color Doppler sonography accurately depicts fibroid vascularity and in some cases can reveal collateral flow not depicted by uterine artery arteriography.     

Reformulation and drop size of apraclonidine hydrochloride.

We performed a prospective, double-masked, placebo-controlled, six-period, cross-over study in which normal subjects were randomly assigned to treatment and compared three different formulations of apraclonidine hydrochloride (the present commercially available formulation, and formulations with hydroxypropylmethylcellulose or lysolecithin). We also evaluated the efficacy of a 16-microliters and 30-microliters drop size. The magnitude and duration of decrease in intraocular pressure was comparable for all formulations. Most subjects tolerated all formulations well with only a few reporting any side effects. The best-tolerated formulation was 0.5% apraclonidine hydrochloride delivered with a 16-microliters drop size. Dry mouth developed frequently with the commercially available 1% apraclonidine solution. Blurred vision complicated the use of the formulation containing hydroxypropylmethylcellulose. Both dry mouth (P less than .05) and blurred vision (P = .004) were statistically significant side effects.     

Acute renal failure in bone marrow transplantation.

Acute renal failure (ARF) is a serious complication in clients who have undergone bone marrow transplantation (BMT). The majority of cases develop as a result of intrarenal damage. Renal ischemia or nephrotoxic drugs, free hemoglobin, and free myoglobin contribute to acute tubular necrosis (ATN), which is the most likely cause of ARF in BMT clients. Nursing care of hospitalized BMT clients is directed toward the prevention of ARF by identifying clients who are at risk, the early diagnosis of renal impairment, and the administration of comprehensive treatment. Nurses play a vital role in the early diagnosis of renal impairment by assessing the client's fluid status, serum and urine electrolyte levels, and daily weights. The nursing role in managing clients with ARF includes preventing drug nephrotoxicity, maintaining fluid and electrolyte balance, preventing infection, and providing emotional support.     

Use of long catheters for multipatient anesthetic monitoring at high respiratory frequencies

Anesthetic gases from several patients can be monitored simultaneously with a centrally located mass spectrometer. Such monitoring requires catheters from patient to spectrometer that are several meters long. Scamman (J Clin Monit 1988;4:227–229) found that when the respiratory frequency is high, as with infants, the CO₂ signal from the patient is unacceptably distorted during passage down the catheter. This is due to Taylor dispersion of the input signal. An outline of the theory of Taylor dispersion is given. The equations describe the interaction between the velocity distribution (which, in laminar flow, is parabolic) and the radial diffusion of CO₂. This interaction keeps a tracer signal together in a pulse, as it moves down the tube with themean velocity, spreading somewhat as it proceeds. How much does an initially sharp signal become blurred? The spread of such a signal when it reaches the detector, measured in time, can be expressed in various ways. Measurement is complicated, however, by the fact that the gas pressure may fall by as much as a factor of 10 along the line. The resultant expansion and acceleration of the gas cannot be ignored. A full treatment of this complication is given elsewhere, but the following simple equation is described: {ie237-1} Typically, the spread time is up to a quarter of a second for catheters of 50 m, such as used by Scamman. This is comparable with the period of CO₂ rise and fall for infants and explains the serious distortion in wave form that Scamman found. Some distortion can be eliminated by reducing R to 0.1 or less, but the extent of this improvement is small. Ideally, for fast-breathing patients, the catheter length should be reduced to 20 m or less, if possible.     

Induction of Leydig cell adenomas by ammonium perfluorooctanoate: a possible endocrine-related mechanism.

Ammonium perfluorooctanoate (C8) produced an increased incidence of Leydig cell adenomas in Crl:CD BR (CD) rats fed 300 ppm for 2 years. A hormonal (nongenotoxic) mechanism was examined since C8 was negative in short-term tests for genotoxicity. Adult male CD rats were gavaged with either 0, 1, 10, 25, or 50 mg/kg C8 for 14 days. In addition, a control group was pair-fed to the 50 mg/kg C8 group. A dose-dependent decrease in body and relative accessory sex organ (ASO) weights was seen, with the relative ASO weights of the 50 mg/kg group significantly less than those of the pair-fed control. Serum estradiol levels were elevated in the 10, 25, and 50 mg/kg C8-treated animals. Estradiol levels in the 50 mg/kg C8 group were 2.7-fold greater than those in the pair-fed control. The increase in serum estradiol levels occurred at the same dose levels as the increase in hepatic beta-oxidation activity. A statistically significant downward trend with dose was seen in serum testosterone levels when compared with the ad libitum control. However, when the 50 mg/kg C8-treated rats were compared with their pair-fed control, no significant differences were seen. Challenge experiments, which can identify the presence and location of a lesion in an endocrine axis, were undertaken to clarify the significance of this downward trend in serum testosterone following C8 exposure. In the challenge experiments, adult CD rats were gavaged with either 0 or 50 mg/kg C8 for 14 days. One hour before termination, rats received either a human chorionic gonadotropin (hCG), gonadotropin-releasing hormone (GnRH), or naloxone challenge. Following hCG challenge, serum testosterone levels in the 50 mg/kg C8 were significantly decreased (50%) from those in the ad libitum controls. Similar decreases, although not significant, were seen in serum testosterone following GnRH and naloxone challenge. The challenge experiments suggest that the decrease in serum testosterone following C8 exposure is due to a lesion at the level of the testis. In addition, progesterone, 17 alpha-hydroxyprogesterone, and androstenedione were examined in the 50 mg/kg C8-treated males following hCG challenge. A 60% decrease was observed in androstenedione levels in the C8-treated animals from those in the ad libitum controls; no other differences were seen. These data suggest that the decrease in serum testosterone following hCG challenge may be due to a decrease in the conversion of 17 alpha-hydroxyprogesterone to androstenedione. The observed effects described above can be attributed to the elevated serum estradiol levels.(ABSTRACT TRUNCATED AT 400 WORDS)     

Inhibition and metabolite complexation of rat hepatic microsomal cytochrome P450 by tricyclic antidepressants.

Administration of imipramine (IMIP) and other tricyclic antidepressants to humans and experimental animals has been associated with inhibition of hepatic cytochrome P450 (P450)-mediated drug oxidation. This study investigated the capacity of several structurally related tricyclic antidepressants to inhibit microsomal P450 activity in vitro. It was found that IMIP, desipramine (DES), amitriptyline (AMIT) and nortriptyline (NOR) were poor inhibitors of P450 activity unless they were preincubated with microsomes and NADPH prior to transfer to flasks containing substrate. Thus, subsequent experiments characterized the time-dependent intensification of inhibition produced by the drugs. Preincubation of the N-methylaminoalkyl agents DES and NOR (200 microM) with NADPH-supplemented microsomes for 30 min led to an approximate 30% decrease in spectrally apparent P450 content; the N,N-dimethylaminoalkyl drugs IMIP and AMIT did not significantly decrease apparent P450 content. Analysis of optical difference spectra of microsomes during NADPH-mediated metabolism of these drugs revealed a prominent increase in absorbance at 454 nm with DES and NOR but not IMIP or AMIT. Monospecific antibodies to the male-specific P450 2C11 and, to a lesser extent, P450 3A2 were effective in preventing the formation of the DES metabolite 454 nm-Soret peak. In addition, the 454 nm absorbance was not produced by the incubation of DES with NADPH-fortified hepatic microsomes from adult female or immature male rats. Studies with the steroid substrate testosterone, which undergoes P450-specific positional hydroxylation, indicated that P450 2C11-mediated 2 alpha- and 16 alpha-hydroxylation were most susceptible to the time-dependent intensification of inhibition produced by DES (8.5 and 7.0 min preincubation required for loss of 50% activity, respectively) and NOR (4.0 and 4.0 min for loss of 50% of both activities). The 6 beta- (P450 3A2) and 7 alpha-hydroxylase (P450 2A1) pathways were somewhat less susceptible to inhibition than 2 alpha- and 16 alpha-hydroxylation. These findings suggest that DES and NOR form a metabolite intermediate (MI)-complex, characterized by a Soret region absorbance maximum near 454 nm in the optical difference spectrum, with microsomal P450 in male rat liver in vitro. Studies with the steroid substrate testosterone as well as immunoinhibition experiments are consistent with the proposition that this MI complex forms principally with the male-specific enzymes P450 2C11 and 3A2. Although a human orthologue of P450 2C11 has not yet been identified, P450s of the 3A subfamily are quantitatively important enzymes in human liver. MI complexation of such enzymes could be a feasible underlying mechanism for certain clinically important drug interactions involving tricyclic antidepressants.