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Biomedical subjects

D Johnson

Publications and source records attributed to D Johnson.

At least 253 records · Page 14Linked to original sources
PubMed1997

Invasive group A streptococcal infections in North Carolina: epidemiology, clinical features, and genetic and serotype analysis of causative organisms.

During 1994 and 1995, an increase in the number and severity of group A streptococcal (GAS) infections was noted in North Carolina. Ninety-six patients had GAS recovered from blood and other sterile body fluids, abscesses, and soft tissue. The overall case fatality rate was 11% but was much higher in patients with toxic shock syndrome (55%) and necrotizing fasciitis (58%). Recent invasive GAS isolates were compared with pre-1994 invasive isolates and temporally related pharyngeal isolates by M protein serotyping, pulsed field gel electrophoresis (PFGE), and polymerase chain reaction amplification of the streptococcal pyrogenic exotoxin A gene. Serotypes M1 and M3 accounted for 50% of recent invasive isolates (1994-1995) and 58% of pharyngeal isolates (1994). The latter isolates demonstrated PFGE patterns that were identical to invasive M1 and M3 strains, suggesting that pharyngeal infections may have served as a reservoir for virulent GAS clones.

Abscess↗
PubMed1997

Functional teams lead to Joint Commission success.

As the Joint Commission on Accreditation of Healthcare Organizations (Joint Commission) has shifted the focus of its survey process to the organization as a whole, new techniques are needed to prepare for surveys. Staten Island University Hospital used teams based on the eleven important functions to achieve a successful survey.

Accreditation↗
PubMed1997

A computer database for the preparation of transport documents for radiopharmaceuticals.

The preparation of radiopharmaceuticals in central radiopharmacies for distribution to several hospitals is practised widely. Transport of the radiopharmaceuticals is usually by road and this activity is regulated by legislation. Two requirements of the legislation are that the consignor issues a transport document for each consignment and maintains a record of all transport of radioactive material. This paper describes a computer database that has been developed for use in a central radiopharmacy to achieve these requirements.

Databases, Factual↗
PubMed1997

Conflict, the continuum and chronic emergencies: a critical analysis of the scope for linking relief, rehabilitation and development planning in Sudan.

The concept of the 'relief-to-development continuum' has been the subject of renewed interest in recent years. Concerned by the rise in relief budgets over the past decade and the absolute fall in development aid resources, support has been growing for the concept of developmental relief. In the context of complex political emergencies, it has been argued further that as effective development aid can reduce vulnerability to the impact of natural hazards, so it might also be used to contribute to a process of conflict prevention. In this way, the concept of the relief-development continuum has become entwined with broader discussions about the contribution of official development assistance management. Drawing on a Review of Operation Lifeline Sudan (OLS), this paper cautions against uncritical application of the concept of the continuum in complex political emergencies and rehabilitation in particular, in the current Sudanese context. It argues that in order to move legitimately from relief aid programming to development aid programming, three fundamental conditions must be in place: first, a minimum level of security, respect for human rights and humanitarian access. Second, empirical evidence from the field needs to demonstrate that the emergency is over. Finally, moving from relief to development aid programming is contingent on donor governments accepting the legitimacy of national governmental structures and of the rebel movements. In other words, for donor governments, moving along the continuum is in significant part determined by foreign policy considerations, not only technical ones. Consideration needs to be given to the actual and perceived legitimation of the different movements that a move to rehabilitation might be seen to imply. The paper argues that none of these conditions had been satisfied in Sudan by mid-1997. Instead of a process of normalisation paving the way to long-term development, the current situation in Sudan is better described as a chronic political emergency. In such a context, uncritical pursuit of developmental strategies may negatively affect the welfare of conflict-affected populations.

Humans↗
PubMed1997

Reproducibility of ventricular fibrillation characteristics in patients undergoing implantable cardioverter defibrillator implantation.

INTRODUCTION: The purpose of this study was to evaluate the immediate reproducibility of local electrogram characteristics recorded during repeated episodes of induced ventricular fibrillation (VF) in patients undergoing implantable cardioverter defibrillator (ICD) implantation. METHODS AND RESULTS: Power spectral analysis (using a fast Fourier transform algorithm) of electrograms recorded during 3 seconds of VF were analyzed in 24 patients undergoing ICD implantation using a Medtronic Transvene lead. Patients had 2 to 7 episodes of VF that were induced during defibrillation threshold testing. VF was induced by burst pacing (n = 20) or T wave shock (n = 4). Simultaneous electrograms during VF were recorded from a Medtronic Transvene lead with the following configurations: (1) a narrow spaced (12 mm) dedicated bipole used clinically for sensing; (2) a unipolar electrogram from the right ventricular coil; and (3) a widely spaced (18.3 mm) integrated bipole using the distal tip and the coil. Intraclass correlation coefficients (ICCs) were determined to examine the reproducibility of these VF characteristics among VF episodes in each patient. Recordings from both bipolar configurations had ICCs from 0.40 to 0.55, whereas unipolar recordings ICCs were below 0.40. Reproducibility was similar for dedicated and integrated recordings. CONCLUSIONS: Frequency characteristics of repeated episodes of VF induced in the same subjects show fair-to-good but not excellent reproducibility. Bipolar recordings were far more reproducible than unipolar recordings, but both bipolar configurations had similar reproducibility. These findings have implications for both the pathophysiology of induced VF and the design of VF detection algorithms.

Adult↗
PubMed1997

Effect of severity of meningitis on fungicidal activity of flucytosine combined with fluconazole in a murine model of cryptococcal meningitis.

We studied the effect of the severity of meningitis on the response to therapy with fluconazole and flucytosine in a murine model of cryptococcal meningitis. Meningitis was established by intracerebral injection of Cryptococcus neoformans. The severity of meningitis was varied by delaying the onset of treatment from 3 to 7 days. Animals were sacrificed after 14 days of treatment, and the numbers of C. neoformans per gram of brain tissue were quantified. The range of effective dose combinations of fluconazole and flucytosine became progressively reduced as the severity of meningitis increased. The magnitude of treatment effect, as measured by the numbers of CFU/gram of brain tissue, was also reduced with increasing severity of meningitis. In this model, as the severity of meningitis increases, higher doses of fluconazole are required to achieve equivalent levels of activity. The combination of fluconazole and flucytosine appears to have the most-potent antifungal effects. This is most readily observed in animals with more-severe meningitis.

Animals↗
PubMed1997

Cellular pharmacology and molecular biology of the trabecular meshwork inducible glucocorticoid response gene product.

Studies of the effects of glucocorticoid (GC) and oxidative stress stimuli in differentiated cultures of human trabecular meshwork (HTM) cells have provided the rationale for our studies of a major new gene termed TIGR (trabecular meshwork inducible GC response). The TIGR clone was isolated by differential library screening using selection criteria based on the induction pattern of a new protein/glycoprotein found in HTM cultures after prolonged but not brief exposure to GCs. This GC induction pattern matched the time course and dose response required for intraocular pressure elevation in patients receiving corticosteroids. The very large, progressive induction of TIGR combined with specific structural features of its cDNA suggested that TIGR should be considered a candidate gene for outflow obstruction in glaucoma. Among the properties of TIGR cDNA were a signal sequence for secretion, several structural features for interactions with glycosaminoglycans and other glycoproteins and putative sites for cell surface interactions. In addition, the leucine zippers in the structure were related to TIGR-TIGR oligomerization that was shown to occur with native and recombinant TIGR protein. The verification that TIGR was a major stress response protein in HTM cells following hydrogen peroxide (or phorbol esters) exposure provided a potential link between GC and oxidative mechanisms thought to be involved in glaucoma pathogenesis. Pharmacological evaluation showed that basic fibroblast growth factory and transforming growth factor beta decreased the GC induction of TIGR, and certain nonsteroidal anti-inflammatory drugs protected against both GC- and oxidation-induced stress responses in HTM cells. Our recent studies of TIGR's genomic structure have shown motifs in the promoter region that suggest a basis by which multiple hormonal/environmental stimuli can regulate TIGR production and by which putative genetic alterations could lead to an overexpression of the protein. Further application of cell biology/biochemistry, molecular biology, genetic and histological approaches will be helpful in understanding the role of TIGR in different glaucoma syndromes.

Aged↗
PubMed1997

Cisplatin, doxorubicin, and cyclophosphamide plus thoracic radiation therapy for limited-stage unresectable thymoma: an intergroup trial.

PURPOSE: To determine the response rate of cisplatin plus doxorubicin plus cyclophosphamide (PAC) in patients with limited-stage unresectable thymoma. In addition, this study was undertaken to determine the toxicity, progression-free survival, and overall survival of combined-modality therapy with PAC plus radiation therapy. PATIENTS AND METHODS: Patients with a histologic diagnosis of limited-stage unresectable thymoma or thymic carcinoma were eligible. Further requirements included a Karnofsky Performance Score of > 60, no prior radiation to the chest, and adequate bone marrow, hepatic, and renal function. No patient had undergone chemotherapy previously. Patients received two to four cycles (repeated every 3 weeks) of cisplatin (50 mg/m2), doxorubicin (50 mg/m2), and cyclophosphamide (500 mg/m2) followed by a total dosage of 54 Gy to the primary tumor and regional lymph nodes for patients with a stable, partial, or complete response to chemotherapy. RESULTS: From November 1983 through January 1995, 26 patients were entered onto the trial. Three patients were ineligible on the basis of pathologic review (lung cancer, germ cell cancer, lymphoma). Toxicity, primarily hematologic, was mild, with only one early death due to a perforated abdominal viscus. Among the 23 assessable patients, there were five complete and 11 partial responses to chemotherapy (overall response rate, 69.6%). The median time to treatment failure was 93.2 months (range, 3 to 99.2+ months), and the median survival time was 93 months (range, 1 to 110 months). The 5-year survival rate is 52.5%. CONCLUSIONS: PAC combination chemotherapy produces response rates in the management of patients with limited thymoma. Combined-modality therapy is feasible and associated with prolonged progressive-free survival. The benefit of combined-modality therapy over radiation therapy alone is suggested for patients with unresectable thymoma.

Adult↗
PubMed1997

Congenital lymphocytic choriomeningitis virus syndrome: a disease that mimics congenital toxoplasmosis or Cytomegalovirus infection.

OBJECTIVE: To describe the clinical characteristics of intrauterine infection with lymphocytic choriomeningitis (LCM) virus, an uncommonly recognized cause of congenital viral infection. PATIENTS: Three infants born in the midwestern United States in 1994 and 1995 with clinical features and serologic studies consistent with congenital LCM virus infection and cases of congenital infection identified by review of the medical literature between 1955 and 1996. RESULTS: Twenty-six infants with serologically confirmed congenital LCM virus infection were identified. Twenty-two infants were products of term gestations, and birth weights ranged from 2384 to 4400 g (median, 3520 g). Ocular abnormalities, macrocephaly, or microcephaly were the most commonly identified neonatal features. Twenty-one infants (88%) had chorioretinopathy, 10 (43%) had macrocephaly (head circumference >90th percentile) at birth, and 3 (13%) were microcephalic (head circumference <10th percentile). Macrocephaly and hydrocephalus developed postnatally in one of the latter infants. Hydrocephalus or intracranial calcifications were documented in five infants by computed tomography or magnetic resonance imaging. Nine infants (35%) died, and 10 (63%) of the 16 reported survivors had severe neurologic sequelae, consisting of spastic quadriparesis, seizures, visual loss, or mental retardation. One-half of the mothers reported illnesses compatible with LCM virus infection, and 25% reported exposures to rodents during their pregnancies. CONCLUSIONS: These cases suggest that congenital LCM virus infection could be an underrecognized cause of congenital infection among infants born in the United States. Because of the clinical similarities of these congenital infections, cases of congenital LCM virus infection can be confused with infections with cytomegalovirus or Toxoplasma gondii.

Apgar Score↗
PubMed1997

Evaluation of a critical pathway for stroke.

The diagnosis of stroke, which is diagnosis-related group (DRG) 014, is the fourth most frequent discharge DRG at Macomb Hospital Center, Warren, Michigan. The length of stay for stroke was 7.52 days before intervention. Quality improvement techniques identified areas of delay that presented opportunities for improvement. After the initiation of a critical pathway that begins its interventions in the Emergency Department, the length of stay decreased to 6.33 days. Quality of care was also improved in delivery time of carotid artery ultrasound examinations, as well as in timeliness of obtaining head computed tomography scans and reports. This article describes the development, implementation, and results of a stroke critical pathway that was implemented to address excessive length of stay.

Cerebrovascular Disorders↗
PubMed1997

Bridging prevention and practice: public health and family violence.

Public health approaches the primary prevention of family violence by focusing on surveillance, the identification of risk factors, and the development, evaluation, and dissemination of interventions. Physicians and other health care providers are crucial in this process because they are in a unique position to identify at-risk individuals and populations and to implement both broad-based and targeted preventive and intervention initiatives. Incorporating public health principles into medical education and medical practice not only can reduce the severity of this epidemic by strengthening efforts in early detection and expert intervention but also can create effective primary prevention, an important necessary step towards eradicating every disease or condition. This article discusses the role of public health professionals in preventing family and intimate violence. It notes specific findings from public health research, including the cycle of violence and the need to incorporate issues of abuse across the life span, and other factors, into medical education. Addressing family and intimate violence in a caring and sensitive manner is difficult, and incorporating public health principles into medical education and medical practice can forge an effective partnership between medical practitioners and public health professionals. This new partnership represents both an important challenge and a unique opportunity to understand family and intimate violence and thus to develop and evaluate effective short- and long-term solutions.

Attitude of Health Personnel↗
PubMed1997

Cisplatin/etoposide vs paclitaxel/cisplatin/G-CSF vs paclitaxel/cisplatin in non-small-cell lung cancer.

A phase III trial conducted by Eastern Cooperative Oncology Group (ECOG) investigators assessed the possible impact of paclitaxel on survival, response, and toxicity in patients with advanced non-small-cell lung cancer. Three regimens were compared: cisplatin/etoposide, paclitaxel/ cisplatin/granulocyte colony-stimulating factor (G-CSF), and paclitaxel/ cisplatin. Patients were randomly assigned to the regimens, each of which was repeated every 21 days over a 17-month period. Response rates were 12% in the cisplatin/etoposide group, 31% in the paclitaxel/cisplatin/G-CSF group, and 26% in the paclitaxel/cisplatin group. Significant differences in response were observed between the cisplatin/etoposide and paclitaxel/cisplatin/G-CSF groups and the cisplatin/etoposide and paclitaxel/cisplatin groups; there was no significant difference between patients treated with paclitaxel/cisplatin vs paclitaxel/cisplatin/G-CSF. Both paclitaxel regimens were associated with significantly higher response rates compared with etoposide/cisplatin. Based on preliminary survival analyses, the investigators concluded that the paclitaxel regimens may be associated with superior survival.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1997

Maternal melanoma metastatic to the placenta: a case report and review of the literature.

Metastases of maternal cancer to the placenta and fetus are rare in cases of maternal primary malignancy. This report describes a case of malignant melanoma metastatic to the placenta, reviews the literature, and discusses the clinical significance. A 33-year-old woman presented at 30 weeks' gestation with multiple metastases from a malignant melanoma diagnosed 4 years previously. Rapid maternal deterioration necessitated premature cesarean delivery, and maternal death occurred 7 days later. The placenta showed multiple metastases of malignant melanoma. The infant, however, is alive and well at 7 months of age. Melanoma in pregnancy rarely results in metastasis to the conceptus, but when it does occur there may be fatal consequences to the fetus. Therefore, the placenta should be thoroughly examined for metastasis, which, if present, should alert the clinician to monitor the infant for development of malignant disease.

Adult↗
PubMed1997

High prevalence of elevated factor VIII levels in patients referred for thrombophilia screening: role of increased synthesis and relationship to the acute phase reaction.

A recent report from the Leiden Thrombophilia Survey identified high factor VIII activity levels as an independent risk factor for venous thromboembolism in a population survey. As the study measure for factor VIII was a one-stage coagulation assay, and since markers for the acute phase reaction were not assessed, it remained uncertain whether the increase was due to a constitutional increased rate of synthesis, to circulating activated factor VIII, or to an acute phase response. We added factor VIII activity assay (FVIII:C), factor VIII antigen (FVIII:Ag), vWF antigen (vWF:Ag), ABO blood group, fibrinogen and C-reactive protein to our routine thrombophilia screen of patients referred because of unexplained thromboembolism. Elevated FVIII:C (> 1.5 iu/ml) emerged as the single commonest abnormality detected in 25.4% of a group of 260 such patients. FVIII:C and FVIII:Ag were highly correlated (p = 0.003), showing that this represented a true increase in FVIII. In 4 of 46 patients this was clearly attributable to an acute phase reaction. Eleven others showed minor elevation of ESR and one of CRP. Neither FVIII:C or FVIII:Ag showed significant correlation with fibrinogen, ESR or C-reactive protein by non parametric analysis. Although there was an excess of patients with B blood group (known to be associated with FVIII:C levels which are approximately 15% higher than those in blood group O), this could not account for the marked elevation of factor VIII observed in these patients. We conclude that factor VIII activity assay should be a routine part of thrombophilia screening. We are investigating the cause of the increased synthesis, initially by means of family studies and linkage analysis with polymorphic markers of the FVIII locus. We postulate that it may be constitutive in some cases and in others an abnormal or exaggerated response to inflammatory stimuli.

ABO Blood-Group System↗
PubMed1997

Inhaled nitric oxide reduction in systolic pulmonary artery pressure is less in patients with decreased left ventricular ejection fraction.

OBJECTIVE: To assess whether inhaled nitric oxide decreases pulmonary artery pressure in patients with depressed left ventricular ejection fraction. DESIGN: Randomized, blinded, crossover clinical trial. SETTING: Tertiary care university referral hospital. PATIENTS: Thirty-three patients with pulmonary hypertension and left ventricular dysfunction or valvular heart disease were recruited by convenience. INTERVENTIONS: Systolic pulmonary artery pressure was measured by Doppler echocardiography during randomized inhalation of either 20 ppm or 40 ppm nitric oxide in 30% oxygen as well as during control periods without nitric oxide. MAIN RESULTS: Systolic pulmonary artery pressure was significantly (P < 0.05) decreased with 20 ppm nitric oxide (53.4 +/- 13.9 mmHg) and 40 ppm nitric oxide (53.1 +/- 14.4 mmHg) compared with either initial control (55.8 +/- 15.3 mmHg) or terminal control (56.3 +/- 15.2 mmHg) values. The regression equation for the change in systolic pulmonary artery pressure (y) as predicted by the left ventricular ejection fraction (x) alone for 20 ppm nitric oxide was y = 13.8x-2.9; R2adj = 0.30, P < 0.0001. For 40 ppm nitric oxide alone, the regression equation was y = 16.3x-3.3; R2adj = 0.25, P < 0.0001. Left ventricular ejection fraction was the most explanatory independent variable in the multivariate equation for nitric oxide-induced change in systolic pulmonary artery pressure (R2 = 0.61, P = 0.0000). The change in systolic pulmonary artery pressure was -5.1 +/- 5.2 versus 0.8 +/- 4.9 mmHg (P < 0.0000) in patients with left ventricular ejection fractions greater than 0.25, and 0.25 or less, respectively. CONCLUSIONS: These data imply that in patients with left ventricular ejection fraction of 0.25 or less, nitric oxide may not decrease systolic pulmonary artery pressure. Nitric oxide inhalation may result in a paradoxical increase in systolic pulmonary artery pressure in patients with severely depressed left ventricular ejection fraction. This effect would significantly limit the therapeutic role of nitric oxide in patients with severe heart failure.

Administration, Inhalation↗