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Biomedical subjects

B Johnson

Publications and source records attributed to B Johnson.

At least 181 records · Page 10Linked to original sources
PubMed1994

The natural history of familial cavernous malformations: results of an ongoing study.

Cavernous malformations are congenital abnormalities of the cerebral vessels that affect 0.5% to 0.7% of the population. They occur in two forms: a sporadic form characterized by isolated lesions, and a familial form characterized by multiple lesions with an autosomal dominant mode of inheritance. The management of patients with cavernous malformations, particularly those with the familial form of the disease, remains a challenge because little is known regarding the natural history. The authors report the results of an ongoing study in which six families afflicted by familial cavernous malformations have been prospectively followed with serial interviews, physical examinations, and magnetic resonance (MR) imaging at 6- to 12-month intervals. A total of 59 members of these six families were screened for protocol enrollment; 31 (53%) had MR evidence of familial cavernous malformations. Nineteen (61%) of these 31 patients were symptomatic, with seizures in 12 (39%), recurrent headaches in 16 (52%), focal sensory/motor deficits in three (10%), and visual field deficits in two (6%). Twenty-one of these 31 patients underwent at least two serial clinical and MR imaging examinations. A total of 128 individual cavernous malformations (mean 6.5 +/- 3.8 lesions/patient) were identified and followed radiographically. During a mean follow-up period of 2.2 years (range 1 to 5.5 years), serial MR images demonstrated 17 new lesions in six (29%) of the 21 patients; 13 lesions (10%) showed changes in signal characteristics, and five lesions (3.9%) changed significantly in size. The incidence of symptomatic hemorrhage was 1.1% per lesion per year. The results of this study demonstrate that the familial form of cavernous malformations is a dynamic disease; serial MR images revealed changes in the number, size, and imaging characteristics of lesions consistent with acute or resolving hemorrhage. It is believed that the de novo development of new lesions in this disease has not been previously reported. These findings suggest that patients with familial cavernous malformations require careful follow-up monitoring, and that significant changes in neurological symptoms warrant repeat MR imaging. Surgery should be considered only for lesions that produce repetitive or progressive symptoms. Prophylactic resection of asymptomatic lesions does not appear to be indicated.

Adolescent↗
PubMed1994

"Stockless" cost reduction in the operating room.

St. Paul-Ramsey Medical Center in St. Paul, MN became one of the first hospitals in the United States to initiate a "stockless" par level inventory system. Successes with stockless led the hospital to look at implementing it in the OR to achieve a reduction of expense to revenue. Materiel Management and Surgical Services discussed a number of issues relevant to implementing a stockless program, including product flow, accuracy and cost of case carts and preference cards, item pricing, committed usage of items brought into the system and establishment of a steering committee. Specific OR issues and practices required evaluation and adjustment, such as the routine use of emergency direct ordering. Information systems support was brought in and a products committee established to do education and oversee the program. Savings for 1993-94 were $185,146.

Cost Savings↗
PubMed1994

Discern--an integrated prospective decision support system.

We present a new integrated decision support tool, called Discern, for prospective case management within a comprehensive Healthcare Network Architecture (HNA). Discern is an event-driven, expert system tightly integrated into this architecture. It can perform a variety of actions including generating alerts, ordering tests, and entering results. Over 100 institutions use Discern to automate care processes. Discern was designed to meet the demanding requirements for effective decision support.

Decision Making, Computer-Assisted↗
PubMed1994

Clinical and computer-assisted evaluations of the stain removal ability of the Sonicare electronic toothbrush.

Two single-blind clinical studies investigated the stain removal properties of Sonicare, a new electronic toothbrush that combines sonic vibrations and dynamic fluid activity with mechanical scrubbing to clean tooth surfaces. In one study, 30 subjects used a 0.12% chlorhexidine mouthrinse (Peridex) for two weeks to accumulate stain, and then were assigned to either Sonicare or a manual toothbrush (Oral-B P-35). The subjects brushed with their assigned device for 2 minutes twice a day. In a second study, 19 subjects with extrinsic stain due to coffee, tea, or tobacco (CTT) causes were randomly assigned to either Sonicare or a manual toothbrush (Crest Complete). These subjects also brushed for 2 minutes twice a day, with additional brushing on the stained areas. Stain on the labial surfaces of the subjects' anterior teeth was evaluated with the Lobene index at the pretrial, 2-week, and 4-week periods. Clinical analysis indicated that use of Sonicare resulted in Peridex stain reductions of 54% and 50% after 2 and 4 weeks, respectively, and reductions in CTT stain of 39% and 82% at similar time points. The manual toothbrush resulted in stain increases of 4% and 24% in the Peridex study and CTT stain decreases of 41% and 39% after 2- and 4-week brushing periods. Computer image analysis was performed on photographic records from the CTT stain study and showed a high correlation with the Lobene index (r = 0.82). The results of these two independent studies indicate that Sonicare is superior to the manual toothbrushes studied in removing both Peridex and CTT stains.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Cardiac resuscitation by retroaortic infusion of blood.

Current methods of closed-chest cardiac resuscitation generate coronary perfusion pressures that rarely exceed one fourth of normal, and this decreases with prolongation of cardiac arrest. The resuscitation effort is therefore almost uniformly unsuccessful when precordial compression is initiated after 8 minutes of untreated cardiac arrest. This report introduces a new option for cardiac resuscitation by infusion of oxygenated blood into the ascending aorta such as to transiently increase the pressure gradient for coronary perfusion. Thirty-six anesthetized, mechanically ventilated normovolemic rats were investigated. Cardiac arrest was induced with an alternating current delivered through an electrode catheter advanced into the right ventricle. Ventricular fibrillation was untreated for 4, 6, or 8 minutes, after which resuscitation was attempted without blood infusion, with infusion of oxygenated blood, or with infusion of oxygenated blood containing 30 mg/kg epinephrine. The boluses of blood were delivered through a catheter advanced from the right carotid artery into the ascending aorta. Except for mechanical ventilation and direct current precordial countershock for electrical defibrillation, no other mechanical resuscitation intervention, and specifically no precordial compression, was administered. None of six control animals that received either no retroaortic infusion or right atrial infusion was resuscitated after 4 minutes of untreated ventricular fibrillation. Each of five animals was successfully resuscitated by retroaortic infusion after 4 minutes of untreated cardiac arrest; one was resuscitated after 6 minutes, and none was resuscitated after 8 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Cervicography.

Explore the source record for details and available documents.

Cervix Uteri↗
PubMed1993

Purification and partial amino acid sequence of a mu opioid receptor from rat brain.

A rat brain opioid receptor protein was isolated by binding [epsilon-biotinyl-Lys32] beta-endorphin to membranes, solubilizing the receptor-ligand (R.L) complex with deoxycholate-lysophosphatidylcholine and purifying on immobilized streptavidin and wheat germ agglutinin. The purified glycoprotein had a molecular mass of 60-70 kDa. Recovery of this protein was blocked by the nonselective opioid antagonist naloxone and the highly mu-selective agonist [D-Ala2,N-methyl-Phe4,Glyol5]-enkephalin but not by the highly delta-selective agonist [D-Pen2,4'-Cl-Phe4,D-Pen5]enkephalin when these compounds were added as competitors at the binding step. The 60-70-kDa receptor protein co-purified through the streptavidin column with 40-kDa protein recognized by anti-Gi alpha antibodies. GTP and Na+ influenced dissociation of the solubilized R.125I-L complex and elution of the receptor and G protein from streptavidin in fashions consistent with the pharmacology of mu-opioid receptors. A 23-amino acid residue sequence from the purified receptor differs at 4 positions from a similar sequence in the murine delta-opioid receptor and is encoded within a novel rat brain cDNA isolated by polymerase chain reaction with oligonucleotide primers related to the murine delta-opioid receptor gene.

Amino Acid Sequence↗
PubMed1993

Edatrexate in patients with soft tissue sarcoma. Activity in malignant fibrous histiocytoma.

BACKGROUND: Chemotherapy has had little impact on the natural history of soft tissue sarcoma, and often is associated with serious toxicity. Edatrexate, an investigational antifolate, is active in patients with lung cancer, and has cytotoxic activity in human sarcoma cell lines. METHODS: Edatrexate was administered to 36 patients with measurable, advanced soft tissue sarcoma who had not previously received chemotherapy. The drug was given weekly for 5 weeks, then every other week. The initial dose, 80 mg/m2, was escalated by 10 mg/m2 every 2 weeks in the absence of toxicity. Eleven patients had leiomyosarcoma, 7 had malignant fibrous histiocytoma (MFH), and 5 had liposarcoma; the remainder of cell types included hemangiopericytoma (4), angiosarcoma (3), synovial (2), spindle cell (2), extraosseous chondrosarcoma (1), and fibrosarcoma (1). RESULTS: Thirty-five patients are evaluable. Partial response (PR) was seen in five of the seven patients with MFH; no other major responses occurred. Overall, the response frequency was 14% (two-sided 95% confidence interval, 3% to 26%). Median duration of PR was 6 months (range, 4-18 months). One patient had a minor tumor regression, and six had stable disease. Myelosuppression was generally mild; only three patients had grade 3 hematologic toxicity. Modification of dose or schedule was required in 50% of patients for mucositis. Fatigue was a common toxicity, seen in 66% of patients, but was tolerable in the majority. A rash was seen in 46% of patients; one patient had hepatic toxicity. CONCLUSIONS: Overall, the activity of edatrexate in this study, dominated by patients with either visceral or vascular sarcoma, was poor. However, the responses observed in patients with metastatic MFH suggests that further evaluation of edatrexate in patients with soft tissue sarcoma is warranted.

Adult↗
PubMed1993

Delayed type hypersensitivity to human cytomegalovirus.

A skin test for immunity to human cytomegalovirus (HCMV) is described in which skin induration is measured after intradermal injection of antigen derived from heat-inactivated Towne strain HCMV or of envelope prepared from the virus. Randomly selected healthy young adult males and females were prescreened for evidence of past infection with HCMV using serologic tests. Each individual was inoculated with heat inactivated whole virion HCMV antigen prepared from serum-free supernatants of HCMV-infected MRC-5 cells, non-infected MRC-5 cell lysates, and Candida extract. HCMV seropositive individuals developed positive skin reactions to both the Candida extract and the HCMV test antigen. No response was observed at the MRC-5 cell lysate inoculation site. The envelope antigen also elicited a response in seropositive individuals. Seronegative individuals who were negative to the HCMV intradermal antigen at the start of the study developed a positive response 1 week after subcutaneous immunization with live attenuated Towne strain HCMV. This response also correlated with the onset of in vitro proliferation responses to HCMV antigens by peripheral blood lymphocytes obtained from the immunized individuals. Furthermore, skin test and lymphocyte proliferation responses remained positive when tested up to 93 days post-immunization. In guinea pig experiments with HCMV, those animals immunized with purified HCMV or a virus envelope preparation developed strong skin reactions to intradermal injection of each of those antigens. In contrast, no reaction was observed in immune animals, either to viral capsid antigen or uninfected cell-lysate antigen, and no reactions were observed to any HCMV antigen in non-immune animals.

Animals↗
PubMed1993

The role of support surfaces and patient attributes in preventing pressure ulcers in elderly patients.

Nurses caring for elderly patients often need to select support surfaces that reduce the likelihood of pressure ulcers, but there is little information about the effectiveness of different support surfaces. This randomized trial compared two support surfaces and investigated patient attributes related to the risk of developing a pressure ulcer. Eighty-four elderly patients were nursed on a convoluted or solid foam overlay and assessed three times a week for pressure ulcers. Stepwise Cox proportional hazards regression revealed a statistically significant relationship between the risk of developing a pressure ulcer and the variables mobility and type of support surface.

Aged↗
PubMed1993

The Ah receptor nuclear translocator gene (ARNT) is located on q21 of human chromosome 1 and on mouse chromosome 3 near Cf-3.

We have mapped the Ah receptor nuclear translocator (ARNT) gene to a conserved linkage group located on mouse chromosome 3 and human chromosome 1. EcoRI-digested DNA from a panel of 17 human x mouse somatic cell hybrids was probed with a cDNA fragment of the human ARNT gene. Six of the 17 independent mouse x human hybrids were positive for human bands. Human chromosome 1 showed complete cosegregation with the gene, whereas discordant segregation was observed for all other human chromosomes. The human gene was localized to 1q21 by using DNA from mouse x human hybrid clones that retain translocations involving human chromosome 1, by segregation analysis in nine informative CEPH families, and by in situ hybridization. The mouse homologue was mapped to mouse chromosome 3 using a panel of 16 hamster x mouse somatic cell hybrids. Six of 16 mouse x hamster hybrids were positive for mouse bands, showing complete concordance with mouse chromosome 3. The mouse Arnt gene was regionally mapped on chromosome 3, using linkage analysis in an interspecific backcross. The results indicate that the mouse gene resides about 40 cM from the centromere and about 10 cM proximal to Cf-3, the gene for tissue factor.

Animals↗
PubMed1993

Myocardial hypercarbic acidosis reduces cardiac resuscitability.

BACKGROUND: The severity of spontaneous myocardial hypercarbic acidosis during cardiac arrest previously has been predictive of the likelihood of restoring spontaneous circulation. The present study investigated whether hypercarbia itself impairs cardiac resuscitation. Since coronary perfusion pressure is the overriding determinant of cardiac resuscitability, we used a porcine model of cardiac arrest in which coronary perfusion pressure was controlled. METHODS: In 31 domestic pigs anesthetized with pentobarbital, the lungs were mechanically ventilate. Myocardial carbon dioxide tension and hydrogen ion concentration were measured by sensors advanced into the myocardium. After 15 min of untreated ventricular fibrillation, venoarterial extracorporeal circulation was initiated. Animals were randomized to receive a carbon dioxide gas fraction in the extracorporeal perfusate of 0.00, 0.10, 0.30, or 0.50 with oxygen concentration maintained constant at 0.50. Extracorporeal flow was adjusted to maintain a coronary perfusion pressure in the range of 60-80 mmHg, a level of predictive resuscitability. RESULTS: The proportion of animals successfully resuscitated and the proportion of animals maintaining spontaneous circulation for 60 min or longer decreased with increasing perfusate PCO2 and concurrent increases in myocardial CO2 tension in the absence of altered oxygen utilization (P < .01). CONCLUSIONS: Hypercarbia, in this experimental setting, was therefore a quantitative determinant of both myocardial resuscitability and the restoration of spontaneous circulation.

Acidosis↗
PubMed1993

Personality disorder, tendency to impulsive violence, and suicidal behavior in adolescents.

Inpatient suicide attempters (n = 37) were compared with never-suicidal psychiatric controls (n = 29) with respect to prevalence and severity of personality disorder, history of aggression and assaultive behavior, and other measures of impulsive violence. Attempters, compared with controls, were more likely to show evidence of personality disorder or trait, particularly those of the borderline type. Attempters showed greater number of borderline symptoms than did controls, even after removing the item relating to suicidality. There were no differences between the groups with respect to lifetime history of aggression, history of assaultive behavior, or self-report measures of a tendency to impulsive aggression. Those attempters with personality disorder were much more likely to have made a previous attempt. The apparently high prevalence of personality disorder among adolescent inpatient suicide attempters indicates that the social impairment associated with personality disorder be viewed as an important aspect of treatment.

Adolescent↗
PubMed1993

Evaluation of oral erythromycin and local isoniazid instillation therapy in infants with Bacillus Calmette-Guérin lymphadenitis and abscesses.

A randomized placebo-controlled prospective trial was conducted to evaluate the efficacy of erythromycin therapy in 69 patients affected with Bacillus Calmette-Guérin lymphadenitis. When patients who developed subsequent regional abscesses were excluded, erythromycin caused significantly earlier resolution of lymphadenitis (5.1 months vs. 5.7 months for placebo; P < 0.01) compared with placebo. There was no significant difference in the proportion of patients who developed subsequent regional abscesses between the 2 groups (47% for erythromycin, 60% for placebo, P = 0.14). When the entire group of 69 patients was evaluated for "duration to heal" (regardless of subsequent abscess formation), erythromycin therapy (4.1 +/- 1.5 SD months) did not differ significantly from the placebo group (3.5 +/- 1.3 months, P = not significant). Patients who developed subsequent abscess (n = 36) along with those with B. Calmette-Guérin regional abscesses at presentation (n = 27) were further studied to compare oral erythromycin therapy with that of single dose 50-mg intranodal isoniazid instillation. Local isoniazid therapy caused significantly earlier resolution of the abscesses (3.9 months) compared with erythromycin therapy (5.2 months; P < 0.001).

Abscess↗
PubMed1993

Cortivazol increases glucocorticoid receptor expression and inhibits growth of hamster pancreatic cancer (H2T) in vivo.

Glucocorticoids are effective in the treatment of certain leukemias and lymphomas, but their effects on the growth of several solid tumors have not been determined. We report here that cortivazol (CVZ), a potent synthetic glucocorticoid, inhibits the growth of a hamster pancreatic adenocarcinoma, H2T, in vivo. CVZ regulation of glucocorticoid receptor (GR) expression was followed as a specific molecular correlate. H2T cells were injected into cheek pouches of male Syrian golden hamsters, where they formed readily measurable tumors. Two studies were performed. In the first, hamsters were randomized to three groups immediately after injection of tumor cells: control, CVZ (0.1 micrograms/g body wt), or CVZ (0.3 micrograms/g body wt). Injections of either CVZ or its vehicle were administered on a 14-day cycle of 5 treatment days, followed by 9 days off treatment. Tumors were measured and areas calculated weekly. On day 48, the hamsters were killed and the tumors excised, weighed, and analyzed for DNA, RNA, and protein content. In the second study, randomization and treatment schedule were as before, except that on day 33 the hamsters were killed, tumors were excised and weighed, and total RNA from the tumors was isolated. GR mRNA content was determined by filter hybridization with a 32P-labeled GR cDNA probe, and the signal normalized by reprobing for alpha-tubulin as an invariant, independent signal. At either dose, CVZ significantly inhibited H2T tumor area and weight and DNA, RNA, and protein content. Body weights of animals treated with CVZ were not significantly decreased as compared with controls. In addition, GR mRNA in H2T cells was increased approximately twofold by CVZ.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗