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Biomedical subjects

B A Johnson

Publications and source records attributed to B A Johnson.

At least 91 records · Page 5Linked to original sources
PubMed1998

Effects of acute and chronic doses of naltrexone on ethanol self-administration in rhesus monkeys.

The effects of acute and chronic administration of intramuscular naltrexone (0.1, 0.3, 1.0, and 3.0 mg/kg) on oral ethanol (8%) self-administration were examined. Naltrexone (1.0 mg/kg) effects on the self-administration of ethanol concentrations ranging from 0.5 to 8% (w/v) were also investigated. Rhesus monkeys with substantial histories of drug and ethanol drinking served as subjects. During daily 3-hr sessions, monkeys were presented with ethanol solutions, concurrently available with water, under fixed-ratio reinforcement schedules. Naltrexone decreased the consumption of ethanol (g/kg). Biphasic temporal effects were observed within sessions. Naltrexone dose-dependently decreased the number of ethanol deliveries by a maximum of 56% (n = 18; 3 monkeys x 6 sessions) during the first hour of the session. During the second and third hours, however, ethanol intake recovered such that maximum decreases over the 3-hr session were approximately 27% (n = 18), and the mean decrease was 16% (n = 18). Often marked tolerance was observed, such that the effects of acute naltrexone administration were greater than effects after chronic administration. The self-administration of low ethanol concentrations (< or =2% w/v) was increased in several monkeys, by up to 340%, after naltrexone pretreatment. In summary, the effects of naltrexone on ethanol self-administration, in drug- and alcohol-experienced rhesus monkeys, are not characterized by unitary decreases in measures of ethanol self-administration. Rather, differential naltrexone effects were a function of experimental parameters, including the dose and number of naltrexone injections, the ethanol concentration, and the time point of measurement.

Alcohol Drinking↗
PubMed1998

Contemporary spinal CT applications.

Despite the widespread availability of MR imaging, CT remains a vital modality for the evaluation of disorders of the spine, offering superior assessment of bone abnormalities, as well as calcification. Advances in technology have enhanced the capabilities of CT, providing exciting new options for data rendering and display. Depending on the clinical indication, either CT or MR may be the modality of choice in the evaluation of spinal disease.

Calcinosis↗
PubMed1997

Ritanserin in the treatment of cocaine dependence.

Sixty-five cocaine-dependent subjects were enrolled into a 10-week randomized, double-blind study to determine the safety and efficacy of the serotonin-2 receptor antagonist, ritanserin (10 mg/day), in reducing cocaine consumption and craving. All subjects also participated in a structured intensive outpatient psychosocial program. Seventy-three percent of the participants completed the treatment program and follow-up. Subjects experienced a significant reduction in craving: 66.4% and 32.5% for the placebo and ritanserin groups, respectively. These reductions in craving were not paralleled by substantial decreases in cocaine use. Self-reported cocaine use was less frequent in the placebo group; paradoxically, blood levels of its metabolite, benzoylecgonine, were also higher although insignificantly so. Generally, ritanserin was well tolerated but significantly prolonged the QTc interval on the electrocardiogram. This outpatient program is effective at maintaining cocaine-dependent individuals in treatment and reducing craving. Ritanserin (10 mg/day) is not an efficacious adjunct to psychosocial treatment for cocaine dependence.

Adult↗
PubMed1997

A clinical psychotherapy trial for adolescent depression comparing cognitive, family, and supportive therapy.

BACKGROUND: Previous studies in nonclinical samples have shown psychosocial treatments to be efficacious in the treatment of adolescent depression, but few psychotherapy treatment studies have been conducted in clinically referred, depressed adolescents. METHODS: One hundred seven adolescent patients with DSM-III-R major depressive disorder (MDD) were randomly assigned to 1 of 3 treatments: individual cognitive behavior therapy, systemic behavior family therapy (SBFT), or individual nondirective supportive therapy (NST). Treatments were 12 to 16 sessions provided in as many weeks. Intent-to-treat analyses were conducted using all follow-up data. RESULTS: Of the 107 patients enrolled in the study, 78 (72.9%) completed the study, 4 (3.7%) never initiated treatment, 10 (9.3%) had exclusionary criteria that were undetected at entry, 8 (7.5%) dropped out, and 7 (6.5%) were removed for clinical reasons. Cognitive behavior therapy showed a lower rate of MDD at the end of treatment compared with NST (17.1% vs 42.4%; P = .02), and resulted in a higher rate of remission (64.7%, defined as absence of MDD and at least 3 consecutive Beck Depression Inventory scores < 9) than SBFT (37.9%; P = .03) or NST (39.4%; p = .04). Cognitive behavior therapy resulted in more rapid relief in interviewer-rated (vs both treatments, P = .03) and self-reported depression (vs SBFT, P = .02). All 3 treatments showed significant and similar reductions in suicidality and functional impairment. Parents' views of the credibility of cognitive behavior therapy improved compared with parents' views of both SBFT (P = .01) and NST (P = .05). CONCLUSIONS: Cognitive behavior therapy is more efficacious than SBFT or NST for adolescent MDD in clinical settings, resulting in more rapid and complete treatment response.

Adolescent↗
PubMed1997

Familial aggregation of psychiatric disorders in a community sample of adolescents.

OBJECTIVE: To determine whether specific psychiatric disorders and suicide attempts ascertained in a community sample of adolescents show evidence of familial aggregation. METHOD: Fifty-eight adolescent probands recruited from the community and their relatives were assessed as to the presence of specific DSM-III Axis I disorders and suicide attempt, using a combination of family study and family history methodology. RESULTS: In first-degree relatives, there was evidence for specific familial aggregation of suicide attempt (odds ratio [OR] = 12.1 95% confidence interval [CI] = 1.3 to 111.0), substance abuse (OR = 2.7, 95% CI = 1.1 to 6.7), and any Axis I disorder (OR = 2.5, 95% CI = 1.3 to 4.6), even after demographic confounders and familial comorbidity were controlled. Similarly, among second-degree relatives, in analyses controlling for potentials confounders, the disorders-specific aggregation of suicide attempt (OR = 12.3, 95% CI = 1.2 to 130.0), substance abuse (OR = 2.8, 95% CI = 1.6 to 4.8), and any Axis I disorder (OR = 1.5, 95% CI = 1.0 to 2.2) persisted. CONCLUSIONS: The familial aggregation of suicide attempts and psychiatric disorders, particularly of substance abuse and any Axis I disorder, occurs in community samples and is not primarily attributable to referral status.

Adolescent↗
PubMed1997

Preliminary results on the management of unruptured intracranial aneurysms with magnetic resonance angiography and computed tomographic angiography.

OBJECTIVE: The goal was to assess the capability of magnetic resonance angiography (MRA) and computed tomographic angiography (CTA) to replace catheter angiography in the evaluation of unruptured intracranial aneurysms. METHODS: A prospective evaluation of a 1-year period included all patients suspected of harboring unruptured intracranial aneurysms at a single institution. All patients underwent magnetic resonance imaging, MRA, and CTA, for comparison with intraoperative findings or results from catheter angiography. Both MRA and CTA now provide submillimeter resolution of vascular structures, with accurate detection of intracranial aneurysms of a diameter greater than or equal to 3 mm. This resolution calls into question the universal need for catheter angiography in the care of patients with suspected intracranial aneurysms. When the catheter angiography can be avoided, radiological costs can be reduced by as much as two-thirds while eliminating the risk of arterial injury and stroke. RESULTS: Excellent visualization of the intracranial vasculature was provided by both MRA and CTA. No vascular lesion was detected at surgery or by formal angiography that was not visualized by noninvasive angiographic techniques. The three-dimensional anatomy of the aneurysm complex (unavailable with catheter angiography) was well depicted by both MRA and CTA. CTA was unique in its capacity to display the relationship of vascular structures to bone, information that is invaluable for planning operative strategies for lesions such as carotidophthalmic artery aneurysms. Additionally, acquisition of CTA images was very rapid, with a scanning time of less than 1 minute. Both MRA and CTA allowed for retrospective manipulation of data into an infinite number of views, including views that paralleled those encountered through the operative microscope. Additionally, both MRA and CTA can depict the internal anatomy of aneurysms, an ability not possessed by intra-arterial angiography. This ability alerts the surgeon to possible intraoperative risks, such as plaque in the lumen of an aneurysm or calcium within the walls of the arteries. CONCLUSION: Both MRA and CTA provide several advantages over digital subtraction angiography, in addition to reduced costs and avoidance of arterial injury and stroke. These include retrospective manipulation of data in a 360-degree format, visualization of the internal anatomy of arteries and aneurysms, three-dimensional depiction of anatomy, and rapid data acquisition. Preliminary data and a review of the literature suggest that MRA, when used in concert with CTA, can replace catheter angiography in the assessment of select patients harboring unruptured intracranial aneurysms. Although no firm conclusions or generalizations can be drawn from this small cohort of patients, it is hoped that this report will stimulate interest and further study at other institutions.

Aged↗
PubMed1997

The variable MR appearance of primary lymphoma of the central nervous system: comparison with histopathologic features.

PURPOSE: To describe the MR features of primary central nervous system (CNS) lymphoma and to determine whether there is a correlation with histopathologic findings. METHODS: The MR images, pathologic specimens, and clinical records of 23 patients with primary CNS lymphoma were reviewed. The imaging and pathologic characteristics were tabulated and compared by using the standard tests for association in a two-dimensional contingency table. RESULTS: A total of 61 lesions were present in 23 patients; 12 patients (52%) had multiple lesions. All lesions were isointense or hypointense on T1-weighted images, and 53% were isointense or hypointense on T2-weighted images. Twenty patients received intravenous contrast material, and 43 (91%) of 47 lesions enhanced. The three patients who had nonenhancing lesions received steroids before the initial MR studies. Enhancement patterns differed between the immunocompetent and the immunocompromised hosts, with the latter group harboring a higher percentage of rim-enhancing lesions. Twenty-seven (44%) of the lesions were centered in a cerebral hemisphere and 14 (23%) were centered in the central gray matter. There was a statistically significant correlation between a higher degree of necrosis histologically and hyperintensity on T2-weighted MR images. The degree of necrosis also showed a positive correlation with rim enhancement. CONCLUSIONS: Primary CNS lymphoma has a variable MR appearance that correlates with the severity of intratumoral necrosis. These imaging characteristics, as well as lesion location, mean lesion size, and proclivity to harbor necrosis, are altered in the immunocompromised host.

Adult↗
PubMed1996

Spatial distribution of [14C]2-deoxyglucose uptake in the glomerular layer of the rat olfactory bulb following early odor preference learning.

Previous work has shown that odors induce focal uptake of [14C]2-deoxyglucose (2-DG) within the glomerular layer of the main olfactory bulb and that the amount of 2-DG accumulated in these foci increases after early odor learning. To determine if learning-associated changes in 2-DG uptake occur across the entire glomerular layer, we have mapped uptake throughout the layer at fixed angles in coronal sections through the bulb. Resulting arrays for individual bulbs were corrected for differing bulb size and averaged across experimental groups to address the spatial distribution of uptake. The average arrays revealed at least three discrete fields of uptake in naive, peppermint-exposed rats at postnatal day 19 that were not seen in air-exposed littermates. In agreement with previous studies, early preference training with peppermint odor given on postnatal days 1-18 increased 2-DG uptake at postnatal day 19 within odor-dependent patches of uptake in the posterior half of the midlateral bulb, whereas odor-dependent, ventrolateral patches of uptake did not increase to the same extent. In addition, early preference learning was associated with significantly increased 2-DG uptake average over the entire analyzed glomerular layer. These increases were smaller than those within odor-dependent foci and were distributed widely across the glomerular layer, showing low overlap between trained and control rats in anterior regions where peppermint odor did not stimulate 2-DG uptake. The widely distributed increases in 2-DG uptake after learning may reflect changed activity of centrifugal projections that diffusely innervate the glomerular layer.

Animals↗
PubMed1996

Oral fluconazole for vaginal candidiasis.

The recent surge of interest in fluconazole is due to its approval by the U.S. Food and Drug Administration for use as a single 150-mg oral dose in the treatment of vaginal candidiasis. Fluconazole is a triazole antifungal agent that acts primarily by inhibiting sterol synthesis in the fungal cell membrane. Recent studies have shown that a single dose of oral fluconazole is as effective as intravaginal antifungal agents. Many physicians and patients prefer this single-dose regimen because of its low rate of side effects, cost-effectiveness and ease of administration.

Administration, Oral↗
PubMed1996

Synaptophysin-like immunoreactivity in the rat olfactory bulb during postnatal development and after restricted early olfactory experience.

Synaptophysin is a synaptic vesicle protein that provides a marker of synaptic distribution in the brain. We used synaptophysin immunohistochemistry to detect changes in synaptic distribution in the main olfactory bulb during normal early postnatal development and following early olfactory restriction. Synaptophysin-like immunoreactivity appears early in the postnatal development of most bulbar laminae. In the first postnatal week, the entire glomerular neuropil is stained intensely, but by PND 19, the glomerular perimeter becomes more intensely stained than its core. This immunoreactivity is especially dense along that aspect of the perimeter facing the olfactory nerve layer. To determine if this developmental pattern could be affected by early olfactory experience, unilateral naris closure was performed on PND 1. In deprived bulbs at PND 19, the difference in staining between the glomerular border and the glomerular core is significantly less than in either contralateral glomeruli or glomeruli from unoperated animals. The difference between the glomerular border and the glomerular core is greater in bulbs contralateral to a closed naris than in bulbs from unoperated animals. Staining intensity measured over entire glomeruli is not altered by naris closure, nor is staining of other laminae. The changes detected after naris closure indicate that the glomerular distribution of synaptophysin may be particularly sensitive to early olfactory experience.

Aging↗
PubMed1996

Suicidal behavior runs in families. A controlled family study of adolescent suicide victims.

BACKGROUND: While previous studies have shown an increased rate of suicidal behavior in the relatives of suicide victims, it is unclear if this is attributable merely to increased familial rates of psychiatric disorders. Therefore, we conducted a family study of adolescent suicide victims (suicide probands) and community control probands (controls) to determine if the rates of suicidal behavior were higher in the relatives of adolescent suicide probands even after adjusting for differences in the familial rates of psychiatric disorders. METHOD: The relatives of 58 adolescent suicide probands and 55 demographically similar controls underwent assessment for Axis I and II psychiatric disorders, lifetime history of aggression, and history of suicidal behavior (attempts and completions) using a combination of family study and family history approaches. RESULTS: The rate of suicide attempts was increased in the first-degree relatives of suicide probands compared with the relatives of controls, even after adjusting for differences in rates of proband and familial Axis I and II disorders (odds ratio, 4.3; 95% confidence intervals, 1.1-16.6). On the other hand, the excess rate of suicidal ideation found in the relatives of suicide probands was explained by increased familial rates of psychiatric disorders. Among suicide probands, higher ratings of aggression were associated with higher familial loading for suicide attempts. CONCLUSIONS: Liability to suicidal behavior might be familially transmitted as a trait independent of Axis I and II disorders. The transmitted spectrum of suicidal behavior includes attempts and completions, but not ideation, and the transmission of suicidal behavior and aggression are related.

Adolescent↗
PubMed1996

Ritanserin in the treatment of alcohol dependence--a multi-center clinical trial. Ritanserin Study Group.

Four hundred and twenty-three alcohol dependent subjects were enrolled into a 12-week randomized, double-blind, placebo-controlled study to determine the safety and efficacy of the 5-HT2 receptor antagonist, ritanserin (2.5 mg/day or 5 mg/day), in reducing alcohol intake and craving. All subjects received 1 week of single-blind placebo prior to randomization into the 11-week double-blind phase. Additionally, all subjects received weekly individual sessions of manual-guided cognitive-behavioral therapy. Comparing the single-blind period with endpoint, there was approximately a 23% reduction in drinks/day; 34% fall in the total number of drinking days/week; 22% decrease in drinks/drinking day; and a 37% diminution in alcohol craving for all treatment groups. All treatment groups experienced a beneficial clinical outcome as assessed by the Clinical Global Impression Scale. There was, however, no significant difference between treatment groups on any of these measures of alcohol drinking, craving, or clinical outcome. Subjects were of relatively high social functioning at baseline, and this did not change significantly during treatment. Treatment groups did not differ significantly on either medication compliance or reported adverse events. Ritanserin treatment was associated with a dose-related prolongation of subjects' QTc interval recording on the electrocardiogram. These results suggest that alcohol dependent subjects can show marked clinical improvement within a structured alcohol treatment program. These findings do not support an important role for ritanserin in the treatment of alcohol dependence.

Adult↗
PubMed1996

Impact of traumatic subarachnoid hemorrhage on outcome in nonpenetrating head injury. Part II: Relationship to clinical course and outcome variables during acute hospitalization.

Patients with a nonpenetrating head injury and traumatic subarachnoid hemorrhage (tSAH) on admission head computed tomography scan (n = 240) were compared with patients without tSAH matched in terms of admission postresuscitation Glasgow Coma Scale (GCS) values, age, sex, and the presence of one or more types of intracranial mass lesions. Admission Injury Severity Score was higher only in tSAH patients with admission GCS scores between 13 and 15; GCS values at 6, 24, and 48 hours were lower for tSAH patients. Patients with tSAH underwent fewer craniotomies, but more than twice as many tSAH patients had high intracranial pressure at the time of ventriculostomy placement and 6 hours after admission. tSAH patients underwent more chest procedures and their incidence of hypoxia and hypotension was greater. tSAH patients spent more days in intensive care unit, more total days hospitalized, and had worse Glasgow Outcome Scale scores at acute hospital discharge. Fewer tSAH patients were discharged home, and almost 1.5 times as many tSAH patients died during hospitalization. Given a similar overall degree of injury at admission, patients with tSAH associated with a nonpenetrating head injury had a worse outcome than similar patients without tSAH.

Accidents, Traffic↗
PubMed1996

Integration from the small group practice perspective.

For small group practices, ¿appropriate integration¿ is of critical importance because small groups are at high risk of being left behind if they are not well positioned for managed care. Small group practices, however, may find the tasks of evaluating potential partners and getting started on the road to integration rather daunting. Small group practices face unique integration challenges and must plan carefully if they are to integrate effectively.

Capital Financing↗
PubMed1996

Effects of GR 68755 on d-amphetamine-induced changes in mood, cognitive performance, appetite, food preference, and caloric and macronutrient intake in humans.

Pre-clinical studies have suggested that 5-HT(3) antagonists such as GR 68755 oppose mesocorticolimbic dopamine release, which may mediate the important effects of d-amphetamine on positive subjective mood, anorexia, and performance. Twenty-six healthy male volunteers received each of the following treatments in a double-blind, randomized, cross-over design separated by a period of four to seven days: (a) d-amphetamine (20mg orally); (b) placebo; (c) GR 68755 (2mg orally); and (d) GR 68755 plus d-amphetamine. Subjects completed subjective measures of mood, hunger, and satiety. Caloric and macronutrient intake were measured using a test meal. Performance and attention were assessed using standardized computerized tasks. GR 68755 enhanced accuracy on the computerized attention task but failed to reverse significantly any of the effects of d-amphetamine. These results suggest that at these doses GR 68755 pre-treatment does not significantly reduce the effects of d-amphetamine.

Journal Article↗
PubMed1996

The colposcopic examination.

A well-organized and complete colposcopic examination is a vital component of the evaluation of a patient with an abnormal Papanicolaou smear. The properly administered colposcopic examination requires patient preparation, correct equipment and an experienced colposcopist. Under magnified illumination, the cervix is examined for abnormalities. Visualization of premalignant and malignant changes guides the colposcopist in the choice of cervical biopsy sites. The severity and extent of disease can then be histologically determined, and appropriate treatment initiated.

Biopsy↗
PubMed1995

A learned odor evokes an enhanced Fos-like glomerular response in the olfactory bulb of young rats.

Young rats exposed to peppermint odor and reinforcing tactile stimulation from postnatal days (PND) 1-18 increase their preference for that odor relative to controls. This early olfactory memory is accompanied by an 80% increase in the density of glomerular-layer cells displaying Fos-like immunoreactivity in response to the learned odor on PND 19. The difference is observed in midlateral portions of the olfactory bulb that align with foci of 2-deoxyglucose (2-DG) uptake in adjacent sections. Trained and control animals are not different in the Fos-like response of juxtaglomerular cells within ventrolateral 2-DG foci. Ratios of midlateral/ventrolateral response differ significantly between trained and control animals and include differences among cells of three staining intensities. These ratios are correlated with ratios of 2-DG uptake (midlateral/ventrolateral foci), which also differ significantly between trained and control rats. Juxtaglomerular cells associated with 2-DG foci also express Egr-1-like immunoreactivity. However, the midlateral Egr-1 response does not differ between trained and control rats. These results show that early memories can be associated with an increased Fos-like response in a primary sensory area of the CNS. They also suggest that only specific regions within the olfactory bulb are modified following the learning of a given odor in early life.

Animals↗