A prospective study of the effects of prolonged timolol therapy on alpha- and beta-adrenoceptor and angiotensin II receptor mediated responses in normal subjects

AIMS

Long-term treatment with beta 1-selective adrenergic antagonists gives rise to cross-sensitisation of cardiac beta 2-adrenoceptor responses, with no corresponding alteration in beta 1-adrenoceptor responses. We performed a prospective randomised double-blind placebo-controlled cross-over study of the effects of nonselective beta-blockade with timolol on alpha-adrenergic and angiotensin II receptor mediated responses in normal subjects. We also wished to study the time course of beta 1- and beta 2-adrenergic responses after withdrawal of timolol.

METHODS

Six healthy males received timolol 10 mg twice daily or placebo for 14 days. On day 11 of treatment, vascular alpha 1-, alpha 2- and angiotensin II receptor responses were assessed by measuring the blood pressure increases in response to intravenous phenylephrine, alpha-methylnoradrenaline and angiotensin amide respectively, following one dose of timolol 10 mg (to block the beta-adrenergic effects of phenylephrine and alpha-methylnoradrenaline). Both systolic and diastolic blood pressure increased in response to each of these drugs, but these increases were not different on timolol treatment or placebo. Following cessation of treatment with timolol or placebo, beta 1- and beta 2-adrenoceptor mediated responses were assessed by measuring the heart rate responses to treadmill exercise and intravenous salbutamol infusion respectively. Half each of the subjects underwent this 2 days and 3 days respectively, after the end of treatment.

RESULTS

Both exercise-induced and salbutamol-induced tachycardia were not different following placebo or 3 days following the end of timolol treatment. However, 2 days following timolol treatment, both were attenuated; the reduction in salbutamol-induced tachycardia was significant, whilst the reduction in exercise tachycardia did not reach statistical significance. We also measured metabolic responses to exercise and to salbutamol infusion. Exercise induced a rise in plasma potassium and noradrenaline. Salbutamol produced a fall in plasma potassium, a rise in plasma glucose and insulin and also a rise in plasma noradrenaline. All of these changes were not different following placebo or 3 days after the end of timolol treatment; by contrast, 2 days following timolol treatment, all were significantly attenuated, with the exception of the rise in plasma glucose. In addition, the rise in both plasma glucose and insulin in response to an oral load of 75 g glucose were not different post-placebo, 2 or 3 days post-timolol.

CONCLUSIONS

These results show that, following 14 days of nonselective beta-adrenoceptor blockade with timolol, there is evidence of residual beta-adrenoceptor blockade 2 days after drug withdrawal; this finding is in contrast with the known plasma profile of timolol (half-life 3-6 hours), but is consistent with our previous observations of the slow speeds of association and dissociation of timolol with beta-adrenoceptors in vitro. There is no evidence, in this study, of beta-adrenergic sensitisation following timolol withdrawal, nor of cross-regulation of vascular alpha 1-, alpha 2- or angiotensin II receptors in response to nonselective beta-adrenoceptor blockade.

Patients' health as a predictor of physician and patient behavior in medical visits. A synthesis of four studies

OBJECTIVES

Although some patient characteristics are known to be related to physician and patient communication in medical encounters, very little is known about the impact of patients' health status on communication processes. The authors assess relations of patients' physical and emotional health status to verbal and nonverbal communication between physicians and patients in four original studies, and combine results across the four studies using meta-analytic procedures.

METHODS

In four original studies of routine outpatient visits (consisting of more than 250 physicians and more than 1,300 patients), health status was measured and audiotape or videotape records were coded for verbal content and nonverbal cues indicating task-related behavior and affective reactions on the part of both the physician and the patient. Both physical and mental health data were obtained, using physicians and/or patients as sources; in two studies, physicians' satisfaction with the visit also was measured. All available background characteristics for both physicians and patients were controlled via partial correlations. The meta-analytic procedures used were the unweighted and weighted (by sample size) average partial correlations, the combined P across studies (Stouffer method), and the test of effect size heterogeneity.

RESULTS

Physicians showed signs of negative response to sicker or more emotionally distressed patients, both in their behavior and in their ratings of satisfaction with the visit. Sicker patients also behaved more negatively than healthier patients. However, physicians also engaged in a variety of positive and professionally appropriate behaviors with the sicker or more distressed patients. This mixed pattern of responses is discussed in terms of alternative frameworks: the physician's goals, reciprocation of affect, and ambivalence on the part of the physician.

CONCLUSIONS

The patient's health status appears to influence physician-patient communication. In clinical practice, increased attention by physicians to their own and their patients' behavior may enhance diagnosis and prevent misunderstandings.

Effect of metoclopramide on fed-state gastric myoelectric and motor activity in dogs

OBJECTIVE

To investigate the effects of metoclopramide, a putative gastroprokinetic agent, on dogs that had recovered from gastric dilatation-volvulus (GDV), a disorder characterized by delayed gastric emptying.

ANIMALS

6 healthy dogs and 5 dogs after treatment and recovery from GDV.

PROCEDURE

Baseline recordings of gastric electrical and contractile activities were made 8 or 10 days after circumcostal gastropexy and implantation of serosal electrodes and strain-gauge force transducers. Gastric activities were recorded again the next day after treatment with the clinically recommended oral metoclopramide dose (0.3 mg/kg of body weight) administered a half hour before feeding. Recordings were analyzed to determine gastric slow-wave frequency, presence of slow-wave dysrhythmia, slow-wave propagation velocity, coupling of contractions to slow waves, a motility index based on relative contractile amplitudes, and onset of contractions after a standardized meal.

RESULTS

Significant differences in gastric electrical or contractile activities were not detected after metoclopramide treatment in dogs with GDV. Compared with control dogs after metoclopramide treatment, gastric slow-wave propagation velocity was significantly (P = 0.03) faster for the dogs with GDV at postprandial minute 90.

CONCLUSION

At a clinically recommended dosage, metoclopramide treatment did not change gastric myoelectric and motor activities in a way that would promote increased gastric emptying in dogs with GDV.

CLINICAL RELEVANCE

Metoclopramide treatment may not benefit dogs with GDV and delayed gastric emptying.

Anion channel blockers inhibit swelling-activated anion, cation, and nonelectrolyte transport in HeLa cells

The effect of osmotic cell swelling on the permeability of HeLa cells to a range of structurally unrelated solutes including taurine, sorbitol, thymidine, choline, and K+ (96Rb+) was investigated. For each solute tested, reduction in the osmolality of the medium from 300 to 200 mosmol/kgH2O caused a significant increase in the unidirectional influx rate. In each case, the osmotically activated transport component was nonsaturable up to external substrate concentrations of 50 mM. Inhibitors of the swelling-activated anion channel of HeLa cells [quinine, 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid, niflumate, 1,9-dideoxyforskolin, 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB), and tamoxifen] blocked the osmotically activated influx of each of the different substrates tested, as well as the osmotically activated efflux of taurine and I-. Tamoxifen and NPPB were similarly effective at blocking the osmotically activated efflux of 96Rb+. The simplest of several hypotheses consistent with the data is that the osmotically activated transport of the different solutes tested here is via a swelling-activated anion-selective channel that has a significant cation permeability and a minimum pore diameter of 8-9 A.

Evidence for a phosphorylation site in cytomegalovirus glycoprotein gB

As part of our vaccine program, we have purified a recombinant form of human cytomegalovirus glycoprotein B that is able to induce high titers of virus-neutralizing antibodies. The isolated protein was found to be phosphorylated at a serine residue in position -7 from the C terminus of the protein. The corresponding synthetic peptide, HLKDSDEEENV, was an efficient in vitro substrate of casein kinase II.

Stroke in a 24-year-old man

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Education of staff and students in health care settings: integrating practice and research

A cooperative program between the University of Iowa Hospitals and Clinics (UIHC) Department of Social Service (DSS) and the University of Iowa School of Social Work (UISSW) integrates faculty and students with clinicians for both practice and/or research internships. This program has endeavored to enhance practice and research social work through the development of (1) multiple student training programs offering both practice and research placement opportunities, (2) a jointly appointed faculty position between the UISSW and the UIHC DSS designed to improve researchers' access to and involvement with practice and practitioners' involvement in practice research, and (3) specialized student training programs including research projects in practice specialties. This project has helped clinicians conduct research, provided students with practical research experience within a clinical setting, and has increased the likelihood that both staff and students will participate in research.

Gross and histologic evaluation of hepatogastric ligaments in clinically normal dogs and dogs with gastric dilatation-volvulus

OBJECTIVE--To investigate any potential structural differences in hepatogastric ligaments between clinically normal dogs and dogs with gastric dilatation-volvulus (GDV). DESIGN--Case-control study. ANIMALS--Hepatogastric ligaments were examined in 13 large-breed control dogs and in 13 large-breed dogs referred for surgical treatment of GDV. PROCEDURE--Measurements and biopsies of hepatogastric ligaments were performed at the time of surgery, circumcostal gastropexy, for correction of GDV. Serial sections from each ligament were stained with H&E, Masson's trichrome, and elastin stains to assess morphology, including smooth muscle, collagen, and elastic fiber contents. RESULTS--There were no differences observed by light microscopy in incidence or degree of histopathologic alterations between the 2 groups of dogs. The lengths of hepatogastric ligaments in GDV-affected dogs, however, were significantly longer than those of control dogs (GDV-affected dogs, 7.0 [5.0 to 9.5] cm median [range]; control dogs, 5.0 [3.0 to 7.5] cm median [range]; P = 0.01). CONCLUSIONS--Causality can not be inferred from this study. It is not known whether the ligaments were lengthened as a result of GDV or whether the lengthened ligaments predisposed dogs to GDV. CLINICAL RELEVANCE--This finding may reflect increased laxity of the supporting hepatogastric ligament in the right quadrant of the abdomen. An elongated ligament may permit increased stomach mobility and predispose dogs to partial or complete gastric volvulus.

Interpreting and evaluating meta-analysis

This article offers some guidelines for interpreting and evaluating meta-analytic reviews of research. The fundamental goals of meta-analysis are to combine results across studies to yield an overall estimate of effect and to compare effects between studies in order to understand moderating factors. Suggestions are made for what readers should look for in a meta-analysis, and a discussion is provided of several issues that are not often explicitly addressed: choice of unit of analysis, fixed versus random effects, the meaning of heterogeneity, determination of when contrasts are appropriate, and the choice of measure of central tendency. We recommend that readers adopt a skeptical attitude about the results of meta-analysis, particularly when only complex analyses are reported.

Improving physicians' interviewing skills and reducing patients' emotional distress. A randomized clinical trial

BACKGROUND

Despite high prevalence, emotional distress among primary care patients often goes unrecognized during routine medical encounters.

OBJECTIVE

To explore the effect of communication-skills training on the process and outcome of care associated with patients' emotional distress.

METHODS

A randomized, controlled field trial was conducted with 69 primary care physicians and 648 of their patients. Physicians were randomized to a no-training control group or one of two communication-skills training courses designed to help physicians address patients' emotional distress. The two training courses addressed communication through problem-defining skills or emotion-handling skills. All office visits of study physicians were audiotaped until five emotionally distressed and five nondistressed patients were enrolled based on patient response to the General Health Questionnaire. Physicians were also audiotaped interviewing a simulated patient to evaluate clinical proficiency. Telephone monitoring of distressed patients for utilization of medical services and General Health Questionnaire scores was conducted 2 weeks, 3 months, and 6 months after their audiotaped office visits.

RESULTS

Audiotape analysis of actual and simulated patients showed that trained physicians used significantly more problem-defining and emotion-handling skills than did untrained physicians, without increasing the length of the visit. Trained physicians also reported more psychosocial problems, engaged in more strategies for managing emotional problems with actual patients, and scored higher in clinical proficiency with simulated patients. Patients of trained physicians reported reduction in emotional distress for as long as 6 months.

CONCLUSIONS

Important changes in physicians' communication skills were evident after an 8-hour program. The training improved the process and outcome of care without lengthening the visits.

Gastric myoelectric and motor activity in dogs after isoflurane anesthesia

To characterize the effects of isoflurane on gastric motility, gastric electrical and contractile activities were assessed in six healthy adult dogs before and after recovery from anesthesia. Baseline recordings (fasting and fed state) were obtained in unanesthestized dogs 8 days after implantation of serosal electrodes and strain-gauge force transducers. After an overnight fast, dogs were anesthetized with 1.3 minimum alveolar concentration (MAC) isoflurane for 4.5 hours (approximately 6 MAC hours). No other anesthetic or sedative drugs were administered. During anesthesia, ventilation was mechanically controlled to maintain arterial carbon dioxide tension at 36 +/- 4 mm Hg. Gastric electrical and contractile activities (fasting and fed state) were recorded again 18 hours after recovery from isoflurane anesthesia. Recordings were analyzed to determine gastric slow-wave frequency, presence of slow-wave dysrhythmias, slow-wave propagation velocity, coupling of contractions to slow waves, a motility index based on relative contractile amplitudes, and onset and duration of contractions after a standardized meal. The only variable that was significantly decreased 18 hours after 6 MAC hours of isoflurane anesthesia was the gastric motility index during fasting-state phase III. This decrease was not apparent in the fed-state test periods. Our results suggest that, with the exception of gastric motility index during fasting-state phase III, variables for gastric electrical and contractile activities in dogs are unaffected by isoflurane 18 hours after anesthesia.

Interruptive patterns in medical visits: the effects of role, status and gender

Fifty physicians (25 female, 25 male) representing six different levels of status (interns, second and third year residents, fellows and junior and senior staff) were videotaped, each with a male and a female patient. The videotapes were coded for interruptive and overlapping speech, for both physician and patient. Specific categories were successful interruptions, partially successful interruptions, unsuccessful interruptions and overlaps. In addition, all instances of interruptive and overlapping speech were coded as a question or a statement. Results showed, overall, that patients engaged in significantly more interruptive and overlapping speech than did physicians. However, when these variables were analyzed separately for questions and statements, patients were found to interrupt more with statements, whereas physicians interrupted more with questions. High and low status physicians did not differ in their use of interruptions. The few gender differences that did emerge did not indicate a clear pattern of male dominance. The results showing patients to interrupt physicians more than the reverse suggest that interrupting may not solely be a behavior of the higher status person. Together the findings of this study challenge the notion that interruptions simply reflect dominance and/or status and are a behavior more often displayed by males than by females.

Regional anesthesia and local anesthetic-induced systemic toxicity: seizure frequency and accompanying cardiovascular changes

We sought to determine the contemporary frequency of seizures, and the associated cardiovascular changes, resulting from local anesthetic-induced seizures in all patients undergoing brachial plexus, epidural, and caudal regional anesthetics. We investigated the following variables: development and treatment of seizure or cardiac arrest during the regional anesthetic, type of anesthetic (including local anesthetic used), gender, age, ASA physical status class and type of operation (elective or emergent). In addition, each patient who experienced a seizure underwent retrospective review of the acute event to determine the arterial blood pressure and heart rate changes accompanying the seizure, as well as details of the regional block technique. There was a significant difference between the rate of seizure development between epidural, brachia, and caudal anesthetics, with caudal > brachial > epidural. A significant difference was also noted in the rate of seizure development within types of brachial block, with supraclavicular and interscalene > axillary. No adverse cardiovascular, pulmonary or nervous system events were associated with any of the seizures, including the 16 patients who received bupivacaine blocks. The frequency of local anesthetic-induced seizures stratified by block type has a wide range, and cardiovascular collapse after bupivacaine-associated seizure has a low incidence.

Sexual orientation and performance on sexually dimorphic motor tasks

Performance of homosexual and heterosexual men and women on two motor tasks which reliably demonstrate sex differences in opposite directions was examined. A Throw-to-Target Task and the Purdue Pegboard were administered to undergraduate students matched for age and program of study. A two-way ANOVA (Sex x Sexual Orientation) of the Throw data showed a significant interaction, F(1, 90) = 16.22, p < or = 0.001, and a trend for an effect of sex, F(1, 90) = 3.72, p < 0.06. Heterosexual men outperformed heterosexual women, whereas gay men threw less accurately and lesbians tended to throw more accurately than their heterosexual counterparts. Differences in sports history or hand strength did not account for these effects. Analysis of the Pegboard scores found no interaction or main effect of sexual orientation, but the effect of sex was significant, F(1,63) = 7.01, p < or = 0.02. Regardless of sexual orientation, women outperformed men and this difference remained significant even when a measure of finger size was partialed out. This study provides new evidence suggesting an association between sexual orientation and motor-performance profiles. As with cognitive tasks, the motor-performance profiles of homosexuals are composites of some male-typical and some female-typical abilities. To the extent that sociological factors have been controlled, the study suggests that both sexual orientation and motor/cognitive predispositions may have early biological contributions.

Depression research methodologies in the Journal of Personality and Social Psychology: a review and critique

Personality and social psychological studies of depression and depressive phenomena have become more methodologically sophisticated in recent years. In response to earlier problems in this literature, investigators have formulated sound suggestions for research designs. Studies of depression published in the Journal of Personality and Social Psychology (JPSP) between 1988 and 1993 were reviewed to evaluate how well these recommendations have been followed. Forty-one articles were examined for adherence to 3 suggestions appearing consistently in the literature: (a) multiple assessment periods, (b) multiple assessment methods, and (c) appropriate comparison groups. The studies published in JPSP have not adhered well to these standards. The authors recommend resetting minimum methodological criteria for studies of depression published in the premier journal in personality and social psychology.

Induction of urinary tract infection by intraurethral inoculation with Escherichia coli: refining the murine model

Murine models are important for studying the induction and pathophysiology of ascending urinary tract infections (UTI). However, when vesicoureteral reflux occurs during intravesical inoculation of mice with bacterial suspensions, it is difficult to distinguish between naturally ascending infections and those resulting from the inoculation procedure. The current study investigated whether introducing a bacterial suspension into the urethra rather than into the bladder could minimize or eliminate this complication. There were no differences in the intensity or time course of bladder infections induced by intraurethral or intravesical inoculation. In contrast, the prevalence of kidney infections was < 7% in mice given 10 microliters of intraurethral inoculations versus nearly 60% in animals inoculated intravesically with 100 microliters. There were equivalent numbers of bacteria in the kidneys after inoculation by either route. Thus, intraurethral inoculation of female mice with a small volume of bacteria appears to simulate most closely the pathophysiology of ascending UTIs in humans.

Human sperm morphology evaluation pre- and post-Percoll gradient centrifugation

Previous experiments have established a relationship between the morphological characteristics of human spermatozoa and their fertilizing potential in vitro. To assess further the efficiency of Percoll gradient centrifugation (PGC) as a method of sperm selection, we have examined morphological characteristics of spermatozoa from 86 teratozoospermic patients attending Nottingham University Research and Treatment Unit in Reproduction (NURTURE). Patients were divided into groups according to percentage normal morphology in the fresh sample: group A (n = 14), < 5% normal morphology; group B (n = 41), 5-14% normal morphology; and group C (n = 31), > 14% normal morphology. Morphology slides were prepared using Diff Quik staining techniques and evaluated by Kruger strict criteria, under oil immersion, at a magnification of x1000; specific defects, viz. head, neck, cytoplasmic droplets, tail, immature cells, were assessed individually. Following PGC, a sperm sample with enhanced morphology was recovered for group B (P < 0.01) and C (P < 0.005); however, for group A (very severe teratozoospermia) PGC did not select a sample with significantly improved morphological quality. Specific sperm defects affected by PGC were head, neck and immature cells. No significant difference was found for tail abnormalities or cytoplasmic fragments.

Gender in medical encounters: an analysis of physician and patient communication in a primary care setting

The relation of physician and patient gender to verbal and nonverbal communication was examined in 100 routine medical visits. Female physicians conducted longer visits, made more positive statements, made more partnership statements, asked more questions, made more back-channel responses, and smiled and nodded more. Patients made more partnership statements and gave more medical information to female physicians. The combinations of female physician-female patient and female physician-male patient received special attention in planned contrasts. These combinations showed distinctive patterns of physician and patient behavior, especially in nonverbal communication. We discuss the relation of the results to gender differences in nonclinical settings, role strains in medical visits, and current trends in medical education.

Satisfaction, gender, and communication in medical visits

The authors conducted two studies of routine medical visits, investigating the relation of physician gender, patient gender, and physician age to patient satisfaction, and the correlations between communication behaviors and satisfaction separately for different combinations of patient and physician gender. Study 1 was based on videotaped visits to a hospital-based internal medicine practice (n = 97 visits). Study 2 was based on audiotaped visits to 11 different community and hospital-based practices in the United States and Canada (n = 524 visits). In both studies, patients examined by younger physicians, especially younger female physicians, reported lower ratings of satisfaction. These findings were true for male and female patients; however, in both studies, the lowest satisfaction in absolute terms was among male patients examined by younger female physicians. The effects were not explained by patient and physician background characteristics or by measured communication during the visit. Correlations between verbal and nonverbal communication and satisfaction for different combinations of physician and patient gender suggested that gender-related values and expectations influence patients' reactions to physicians' behavior. There also was evidence that patient satisfaction is reflected in the patient's affective behavior during the visit.

Dermatoglyphic asymmetry and sexual orientation in men

Dermal ridges on the fingertips are formed early in fetal life and remain unchanged throughout the life span. The researchers examined dermatoglyphic characteristics (total ridge count and directional ridge asymmetry) in homosexual and heterosexual men. There was no difference between the 2 groups of men in total ridge count, but more gay men demonstrated leftward asymmetry than did nongay men. Although this effect was not accounted for by differences in hand preference, an association was observed between leftward dermatoglyphic asymmetry and an increased incidence of adextrality in homosexual men, but not in heterosexual men. These findings are consistent with a biological contribution to sexual orientation and indicate that such an influence may occur early in prenatal life.

Gender in medical encounters: an analysis of physician and patient communication in a primary care setting

The relation of physician and patient gender to verbal and nonverbal communication was examined in 100 routine medical visits. Female physicians conducted longer visits, made more positive statements, made more partnership statements, asked more questions, made more back-channel responses, and smiled and nodded more. Patients made more partnership statements and gave more medical information to female physicians. The combinations of female physician-female patient and female physician-male patient received special attention in planned contrasts. These combinations showed distinctive patterns of physician and patient behavior, especially in nonverbal communication. We discuss the relation of the results to gender differences in nonclinical settings, role strains in medical visits, and current trends in medical education.