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Biomedical subjects

R Petersen

Publications and source records attributed to R Petersen.

At least 19 recordsLinked to original sources
PubMed2000

No changes in dopamine D(1) receptor mRNA expressing neurons in the dorsal striatum of rats with oral movements induced by long-term haloperidol administration.

Neuroleptic-induced vacuous chewing movements (VCM) in rats, a putative analogue to tardive dyskinesia in man, may involve degeneration within striatum as well as changes in neurotransmitter and receptor expression. In this study, we measured the expression of dopamine D(1) receptor mRNA by dorsal striatal neurons in rats with high and low level of VCM after treatment with haloperidol for 38 weeks. Both the average integrated density of the in situ hybridization signal and number of cells obtained by the stereological cell counting remained within control level, irrespective of the level of haloperidol-induced oral dyskinesia.

Animals↗
PubMed2000

Bacterial subretinal abscess: a case report and review of the literature.

PURPOSE: To report a case of Klebsiella subretinal abscess with a successful visual outcome with treatment and to review the literature pertaining to focal intraocular infection in bacterial endophthalmitis. METHODS: Clinical data including medical history, findings on physical examination, blood cultures, and an abdominal computed tomographic scan were collected in a 32-year-old man with Klebsiella sepsis, liver abscesses, and a focal subretinal abscess. Ocular data including visual acuity, fundus photographs, fluorescein angiography, and ultrasound were evaluated, as were results of culture and histopathologic studies. RESULTS: Despite immediate intervention, including vitreous tap and intravitreal antibiotics, the eye deteriorated, with enlargement of the abscess. A pars plana vitrectomy was performed in which the subretinal abscess material was removed after an extensive retinectomy of the involved area in association with an endophotocoagulative barrier and intravitreal amikacin without gas or oil tamponade. Culture confirmed Klebsiella subretinal infection. A retinal detachment occurred 1 month postoperatively and was successfully repaired. Visual acuity was 20/30 and has remained stable for 14 months. CONCLUSION: Klebsiella endophthalmitis with subretinal abscess formation is a rare but devastating ocular condition. In the present case, prompt intervention with extensive retinectomy, complete abscess excision, and intravitreal antibiotic therapy resulted in unprecedented visual recovery.

Abscess↗
PubMed2000

Screening for intimate partner violence by health care providers. Barriers and interventions.

INTRODUCTION: Routine screening for intimate partner violence (IPV) is endorsed by numerous health professional organizations. Screening rates in health care settings, however, remain low. In this article, we present a review of studies focusing on provider-specific barriers to screening for IPV and interventions designed to increase IPV screening in clinical settings. METHODS: A review of published studies containing original research with a primary focus on screening for IPV by health professionals was completed. RESULTS: Twelve studies identifying barriers to IPV screening as perceived by health care providers yielded similar lists; top provider-related barriers included lack of provider education regarding IPV, lack of time, and lack of effective interventions. Patient-related factors (e.g., patient nondisclosure, fear of offending the patient) were also frequently mentioned. Twelve additional studies evaluating interventions designed to increase IPV screening by providers revealed that interventions limited to education of providers had no significant effect on screening or identification rates. However, most interventions that incorporated strategies in addition to education (e.g., providing specific screening questions) were associated with significant increases in identification rates. CONCLUSION: Barriers to screening for IPV are documented to be similar among health care providers across diverse specialties and settings. Interventions designed to overcome these barriers and increase IPV-screening rates in health care settings are likely to be more effective if they include strategies in addition to provider education.

Battered Women↗
PubMed2000

Violence and reproductive health: current knowledge and future research directions.

OBJECTIVES: Despite the scope of violence against women and its importance for reproductive health, very few scientific data about the relationship between violence and reproductive health issues are available. METHODS: The current knowledge base for several issues specific to violence and reproductive health, including association of violence with pregnancy, pregnancy intention, contraception use, pregnancy terminations, and pregnancy outcomes, are reviewed and suggestions are provided for future research. RESULTS: Despite the limitations of current research and some inconclusive results, the existing research base clearly documents several important points: (1) violence occurs commonly during pregnancy (an estimated 4%-8% of pregnancies): (2) violence is associated with unintended pregnancies and may be related to inconsistent contraceptive use; and (3) the research is inconclusive about the relationship between violence and pregnancy outcomes. CONCLUSIONS: Improved knowledge of the risk factors for violence is critical for effective intervention design and implementation. Four areas that need improvement for development of new research studies examining violence and reproductive-related issues include (1) broadening of study populations, (2) refining data collection methodologies, (3) obtaining additional information about violence and other factors, and (4) developing and evaluating screening and intervention programs. The research and health care communities should act collaboratively to improve our understanding of why violence against women occurs, how it specifically affects reproductive health status, and what prevention strategies may be effective.

Battered Women↗
PubMed2000

Violence against women and reproductive health: toward defining a role for reproductive health care services.

Since a large proportion of U.S. women receive reproductive health care services each year, reproductive health care settings offer an important opportunity to reach women who may be at risk of or experiencing intimate partner violence (IPV). Although screening women for IPV in clinical health care settings has been endorsed by national professional associations and organizations, scientific evidence suggests that opportunities for screening in reproductive health care settings are often missed. This commentary outlines what is known about screening and intervention for IPV in clinical health care settings, and points out areas that need greater attention. The ultimate goal of these recommendations is to increase the involvement of reproductive health care services in sensitive, appropriate, and effective care for women who may be at risk of or affected by IPV.

Adolescent↗
PubMed2000

Half life of chromium in serum and urine in a former plasma cutter of stainless steel.

For 8 years chromium in serum and urine has been followed up in a former plasma cutter of stainless steel who was exposed to airborne dust and fumes containing chromium during this work. After the first examination for serum chromium the exposure ended. Serum chromium concentration has been measured seven times during the period and was initially very high and has subsequently dropped slowly. The half life was 40 months in serum. Urinary chromium has been measured five times. The half life was 129 months in urine. The study shows that exposure to airborne dust and fumes containing chromium may cause accumulation of chromium in the body, and that when exposure ends, elimination of chromium is very slow. Previous studies suggest that chromium mainly accumulates in the lungs.

Chromium↗
PubMed1999

Sensitivity and specificity of three clinical criteria for dementia with Lewy bodies in an autopsy-verified sample.

OBJECTIVE: To evaluate the sensitivity and specificity of the clinical features of three published diagnostic criteria for diffuse Lewy body disease (DLBD) using autopsy-confirmed Alzheimer's (AD), DLBD and AD+DLBD (mixed) dementia cases. DESIGN: Retrospective chart review of an autopsy series of 56 patients selected from the State of Florida Brain Bank on the basis of a pathological diagnosis of either pure AD, DLBD (pure and common forms) or AD+DLBD (mixed) dementia. Clinical features were assessed by three raters blind to the pathological diagnosis. RESULTS: The existing criteria for a clinical diagnosis of DLBD were highly specific (90-100%) but not very sensitive (49-63%) in the differential diagnosis of DLBD versus AD; sensitivity did improve (61-74%) when mixed AD+DLBD cases were eliminated. Clinical features that occur more frequently in DLBD than in AD were unspecified hallucinations, unspecified EPS, fluctuating course and rapid progression. Post-hoc analysis also indicated that hallucinations and EPS were more common early in the disease course of DLBD than in AD. Empirically derived criteria, formulated using the most prevalent clinical features, demonstrated sensitivity values of 57-96% for pure forms and 43-91% for mixed forms. CONCLUSIONS: This study demonstrated that additional improvements in the established criteria for DLBD are needed. Our empirically derived criteria enhanced the distinction of DLBD from AD while allowing the clinician the choice of maximizing sensitivity with acceptable specificity, and vice versa.

Aged↗
PubMed1998

Automated peritoneal dialysis with 'on-line'-prepared bicarbonate-buffered dialysate: technique and first clinical experiences.

BACKGROUND: Automated peritoneal dialysis (APD) has the possibility of increasing the dialysis efficacy by using higher fill volumes, frequent dialysate exchanges, and tidal techniques. It is then possible to treat patients adequately without residual renal function. The drawbacks of the required high amounts of dialysis solution of up to 30 litres per session are the high costs of lactate-based dialysate bags and difficulties for the patients in handling these bags. So far, bicarbonate-based peritoneal dialysate, which may be more biocompatible, is only available for CAPD in double-chamber bags. In APD this could be overcome by 'on-line' preparation of bicarbonate-buffered dialysate using advanced technologies originally designed for on-line preparation of substitution fluid for haemofiltration. METHODS: Four patients without residual renal function were treated with APD five times weekly in a crossover study design. Patients received standard lactate-based (35 mmol/l) treatment (25 litres per session each) in weeks 1 and 3. In week 2 on-line-produced bicarbonate-buffered (37 mmol/l) dialysate was used. This dialysate was prepared by an AK 100 Ultra haemodialysis machine. The machine was modified for adding glucose from a 50% concentrate to the desired concentration of 1.7%. Electrolytes, pH, pCO2, and dialysis efficacy parameters were measured. Microbiological testing was carefully performed. RESULTS: Creatinine clearances, Kt/V, and pCO2 did not vary between the different treatment phases, whereas the pH showed a distinct increase during the bicarbonate phase. Repeated determinations of endotoxins and culturing showed no contamination of the dialysate. The composition of the produced dialysate was reproducible with respect to pH, pCO2, sodium, calcium and bicarbonate, whereas the glucose concentration varied by +/- 20%. CONCLUSIONS: On-line preparation of PD fluid with the AK 100 Ultra is easy and safe to handle. APD with dialysate containing 37 mmol/l bicarbonate provides improved acid base balance and possibly improved biocompatibility, and may lead to a significant cost reduction. Further development in order to provide smaller machines and more precise ways of achieving a desired dialysate glucose concentration is necessary.

Adult↗
PubMed1998

Enhancing work outcome for three persons with traumatic brain injury.

A case study approach is used to illustrate how three survivors of severe traumatic brain injury were able to gain and maintain employment with the assistance of a supported employment programme. Emphasis on the different types of accommodations, including the design and implementation of compensatory strategies, is provided for each case. Finally, on overview of steps that can be taken to enhance the use of such strategies on the job is presented.

Adult↗
PubMed1998

Antiproteinuric efficacy of fosinopril after renal transplantation is determined by the extent of vascular and tubulointerstitial damage.

BACKGROUND: Angiotensin converting enzyme (ACE) inhibitors have been successfully used for treatment of proteinuria after renal transplantation (RTx). Factors possibly responsible for the great inter-patient variance of the antiproteinuric effect (APE) have not yet been investigated in renal-transplanted patients. METHODS: 28 patients after RTx with a persistent proteinuria of more than 1.25 g/d were treated prospectively with does of fosinopril (10-15 mg/d) which were not effective on systemic arterial blood pressure. Prior to initiation of fosinopril, renal graft biopsy was performed in all patients and renal graft artery stenosis was excluded by duplex ultrasound. Serum creatinine and proteinuria were measured prior to, as well as 3 and 8 months after initiation of ACE inhibition, mean arterial pressure was controlled via 24-h measurement and repeated spot measurements. Reduction of proteinuria was correlated with renal histology, serum creatinine, creatinine clearance, mean arterial blood pressure, sodium excretion before therapy and the relative changes of these parameters during therapy respectively. RESULTS: Therapy had to be stopped in 8/28 patients due to side effects including rise of serum creatinine (n = 4). Three patients were excluded due to non-compliance. In the remaining patients (n = 17) proteinuria was reduced from 2.94 +/- 1.66 to 1.82 +/- 1.39 and 2.48 +/- 3.05 g/d after 3 and 8 months respectively, in the mean +/- SD. There was a significant inverse correlation between the APE and the extent of benign nephrosclerosis, interstitial fibrosis and tubular atrophy. No correlation of the APE to any of the other parameters could be demonstrated. CONCLUSIONS: Fosinopril can be administered effectively in a subgroup of proteinuric renal transplant recipients. However, because of a high proportion of patients developing side effects, careful monitoring is obligatory. Our results show that the lesser the degree of chronic morphological injury, the greater is the antiproteinuric effect. Thus, the degree of pre-existing histologically proven damage of the graft may serve as an indicator for the antiproteinuric efficacy of ACE inhibitor therapy after RTx.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1997

pH-dependent stability and conformation of the recombinant human prion protein PrP(90-231).

A recombinant protein corresponding to the human prion protein domain encompassing residues 90-231 (huPrP(90-231)) was expressed in Escherichia coli in a soluble form and purified to homogeneity. Spectroscopic data indicate that the conformational properties and the folding pathway of huPrP(90-231) are strongly pH-dependent. Acidic pH induces a dramatic increase in the exposure of hydrophobic patches on the surface of the protein. At pH between 7 and 5, the unfolding of hPrP(90-231) in guanidine hydrochloride occurs as a two-state transition. This contrasts with the unfolding curves at lower pH values, which indicate a three-state transition, with the presence of a stable protein folding intermediate. While the secondary structure of the native huPrP(90-231) is largely alpha-helical, the stable intermediate is rich in beta-sheet structure. These findings have important implications for understanding the initial events on the pathway toward the conversion of the normal into the pathological forms of prion protein.

Circular Dichroism↗
PubMed1997

Resolution of CNS lesions following treatment of experimental allergic encephalomyelitis in macaques with monoclonal antibody to the CD18 leukocyte integrin.

Experimental allergic encephalomyelitis (EAE) in macaques is an acute inflammatory and demyelinating disease of the central nervous system (CNS) which has been studied extensively as a model of the human demyelinating disease multiple sclerosis (MS). The in vivo administration of monoclonal antibodies against CD18, the common beta-chain of a leukocyte integrin, at the onset of clinical disease, significantly prolonged the survival of nine of 11 macaques (82%) and in some cases completely reversed the clinical appearance of disease. Treatment with anti-CD18 mAbs dramatically reduced the extent of inflammation in brain lesions as determined by magnetic resonance imaging (MRI). These improvements confirm that anti-CD18 mAbs are powerful anti-inflammatory agents in vivo and suggest that such mAbs may provide effective treatment of both demyelinating and inflammatory CNS diseases in man.

Animals↗
PubMed1996

Radio frequency electromagnetic exposure: tutorial review on experimental dosimetry.

Radio frequency (RF) dosimetry is the quantification of the magnitude and distribution of absorbed electromagnetic energy within biological objects that are exposed to RF fields. At RF, the dosimetric quantity, which is called the specific absorption rate (SAR), is defined as the rate at which energy is absorbed per unit mass. The SAR is determined not only by the incident electromagnetic waves but also by the electrical and geometric characteristics of the irradiated subject and nearby objects. It is related to the internal electric field strength (E) as well as to the electric conductivity and the density of tissues; therefore, it is a suitable dosimetric parameter, even when a mechanism is determined to be "athermal." SAR distributions are usually determined from measurements in human models, in animal tissues, or from calculations. This tutorial describes experimental techniques that are used commonly to determine SAR distributions along with the SAR limitations and unresolved problems. The methods discussed to obtain point, planar, or whole-body averaged SARs include the use of small E-field probes or measurement of initial rate of temperature rise in an irradiated object.

Animals↗
PubMed1996

[Value of the emergency therapeutic endoscopy in gastrointestinal hemorrhage].

The experience in therapeutic digestive endoscopy is presented using injection technique with adrenalin-polidocanol of gastrointestinal hemorrhage lesions. One hundred and twenty nine patients were treated endoscopically; the medium age was 60 years; in almost 80% of the cases, peptic ulcer disease were found. The effectiveness was 91.4% when one session procedure was used and in some cases two sessions were applied, giving a final total arrest of hemorrhage of 95.3%. The total mortality still remain high (16.3%) even without bleeding, due to coexisting poor general conditions of the patients. The technique of endoscopic injection is reviewed and the final results of our work are presented.

Adult↗