Biomedical subjects

R Adler

Publications and source records attributed to R Adler.

At least 37 records · Page 2Linked to original sources

PubMed2000

[Reduction of radiation dosage by using digital luminescence radiography on a hand phantom].

PURPOSE: How much can the radiation dose be reduced for hand radiography by using digital luminescence radiography (DLR)? METHODS AND MATERIALS: A hand phantom (3M) with a cyst, two fractures and an "amputation" was digitally exposed in an anterior-posterior orientation using DLR (ADC-70, Agfa). The tube current time product (mAs) was reduced gradually while keeping the voltage constant. The surface entrance dose was measured by a Dosimax sensor (Wellhöfer). Five investigators evaluated the images for characteristics and critical features, pathological findings, visual resolution and contrast. RESULTS: The surface entrance dose at 50 kV/5 mAs was 31 microGy. The images could be evaluated very well down to an average dose of 36% (11 microGy); sufficient images were obtained down to an average dose of 26% (8 microGy). The resolution of the line pairs was the same or reduced by 1 level depending on the investigator. Contrast was assessed as being very good to sufficient. CONCLUSION: For the sufficient exclusion of a fracture the dose can be reduced to at least 39%, for the sufficient assessment of bony union and possible inflammatory changes to at least 42%, to position check and foreign body search to at least 23%. By DLR the following question-referred mAs-product at 50 kV are stated: fracture exclusion 2 mAs, bony union, arthritis and osteomyelitis 2.2 mAs, position check and foreign body search 1.25 mAs.

Foreign Bodies↗

PubMed2000

Immunization levels and risk factors for low immunization coverage among private practices.

OBJECTIVES: Previous studies have indicated that provider characteristics are an important determinant of immunization coverage. The objectives of this study were to: 1) assess immunization coverage levels among 2-year-old children receiving care in private practices in 3 California counties; and 2) evaluate practice and patient risk factors for low immunization coverage. STUDY DESIGN: Cross-sectional chart review of immunization histories and provider survey of immunization policies. SETTING: Forty-five randomly selected, private medical practices in 3 counties in California. PATIENTS: Children 12 to 35 months old, followed by the participating practices. METHODS: Providers underwent a detailed assessment of their immunization coverage and completed a questionnaire describing their immunization policies and procedures. Immunization data were abstracted from randomly selected medical charts of children 12 to 35 months old. Only patients who met the criteria for active status (>/=2 visits and >/=1 visit during the preceding 18 months) were included in analyses. Immunization coverage levels were calculated and logistic regression was used to estimate the risk of underimmunization associated with different practice and child characteristics. RESULTS: Of the 72 eligible practices that were contacted, 45 participated in the study, yielding a participation rate of 62%. The median immunization coverage of participating offices was 54% (range: 0%-91%). Multivariate analysis revealed 5 independent risk factors for underimmunization. The strongest predictors were having fewer than 50% active children in the practice and children having fewer than 8 visits to the provider. Other significant predictors were the percentage of patients in the practice on Medicaid, administering diphtheria-tetanus-pertussis 4 at a separate visit from the Haemophilus influenzae type b booster, and practice location. CONCLUSIONS: These data provide new insights into immunization practices in an important clinical setting that has been poorly characterized previously. Immunization coverage levels were found to be low and significant risk factors for underimmunization were identified. Recommendations are made for immunization policy changes and targeting of immunization improvement interventions at practices that may be at risk for low immunization coverage. immunization, vaccination, immunization programs, primary prevention, private practice, child, preschool, pediatrics, family practice.

California↗

PubMed2000

Herbal vitamins: lead toxicity and developmental delay.

A case of lead poisoning from an Indian herbal vitamin is presented. The patient who was developmentally delayed was given an herbal vitamin from India to strengthen his brain. The tablet contained large amounts of lead and mercury, leading to significant lead burden. Vulnerability of families and lack of awareness of health care professionals of dangers of unknown herbal supplementation are discussed.

Child, Preschool↗

PubMed2000

Neurotrophic factors cause activation of intracellular signaling pathways in Müller cells and other cells of the inner retina, but not photoreceptors.

PURPOSE: Intravitreal injection of brain-derived neurotrophic factor (BDNF), ciliary neurotrophic factor (CNTF), or basic fibroblast growth factor (FGF2) promotes survival of photoreceptors exposed to various types of insults, but it is not known if these survival-promoting effects occur by direct action of the factors on photoreceptors or indirectly through the activation of other cells. In this study, the authors have sought to address this issue by determining which cells in the retina show evidence of activated intracellular signaling pathways acutely and at longer time points after intravitreal injection of these agents. METHODS: Retinas were removed from C57BL/6J mice at 1, 6, or 24 hours after intravitreal injection of 1 microg of human BDNF, rat CNTF, human FGF2, or human transforming growth factor-alpha (TGFalpha), and immunohistochemically stained for phosphorylated extracellular signal-regulated kinase (pERK), phosphorylated cAMP responsive element binding protein (pCREB), or c-fos. Retinal organ cultures were incubated with 10 ng/ml of BDNF, CNTF, FGF2, or TGFalpha for 10 or 30 minutes or 1, 3, or 6 hours and then immunohistochemically stained for pERK, pCREB, or c-fos. RESULTS: Intravitreal injection of BDNF, CNTF, or FGF2 resulted in a rapid increase in pERK immunoreactivity in Müller cells and a rapid increase in c-fos immunoreactivity in Müller, amacrine, and ganglion cells. Immunoreactivity for pERK and c-fos returned to baseline in all retinal cells at 6 or 24 hours after injection, but there was increased staining for glial fibrillary acidic protein (GFAP) in Müller cells at these time points. At no time after injection was there any staining for pERK or c-fos in photoreceptors. Similarly, retinal explants treated with FGF2, BDNF, or CNTF showed increased staining for pCREB, pERK, and c-fos in cells of the inner retina, but not photoreceptors. CONCLUSIONS: These data support the hypothesis that BDNF, CNTF, and FGF2 exert their effects on photoreceptors by acting indirectly through activation of Müller cells and perhaps other nonphotoreceptor cells.

Animals↗

PubMed2000

Final report of the FOPE II Financing of Pediatric Education Workgroup.

Some of the challenges of financing pediatric medical education are shared with all medical education; others are specific to pediatrics. The general disadvantage that funding of graduate medical education (GME) is linked to reimbursement for clinical care has uniquely negative consequences for freestanding children's hospitals because they therefore receive little Medicare GME support. This represents both a competitive disadvantage for such hospitals and an aggregate federal underinvestment in children's health care that now amounts to billions of dollars. The need to subsidize medical student and subspecialty education with clinical practice revenue jeopardizes both activities in pediatric departments already burdened by inadequate reimbursement for children's health care and the extra costs of ambulatory care. The challenges of funding are complicated by rising costs as curriculum expands and clinical education moves to ambulatory settings. Controversies over prioritization of resources are inevitable. Solutions require specification of costs of education and a durable mechanism for building consensus within the pediatric community. Pediatrics 2000;106(suppl):1256-1269; medical student education, continuing medical education, medical subspecialties, children, pediatrics, health maintenance organizations, managed care, hospital finances, children's hospitals.

Child↗

PubMed2000

Green cone opsin and rhodopsin regulation by CNTF and staurosporine in cultured chick photoreceptors.

PURPOSE: To investigate the regulation of visual pigment expression in chick embryo photoreceptor cells by ciliary neurotrophic factor (CNTF), and by the protein kinase inhibitor staurosporine. METHODS: Embryonic day (ED) 8 chick embryo retinal cells were dissociated and cultured at low densities for 3 days, either in control medium or in medium supplemented with CNTF or staurosporine. The cultures were analyzed by immunocytochemistry with the monoclonal antibody Rho4D2, which recognizes chicken rhodopsin and green cone pigment, and by reverse transcription-polymerase chain reaction (RT-PCR) and Northern blot analysis to investigate visual pigment expression at the mRNA level. RESULTS: CNTF increased the number of Rho4D2-immunoreactive photoreceptors in retinal cell cultures, in agreement with previous reports. RT-PCR and Northern blot analysis, however, showed that rhodopsin mRNA was undetectable in both control and CNTF-treated cultures but that CNTF induced significant increases in mRNA levels for the green cone pigment. Staurosporine-treated cultures also had more Rho4D2-immunoreactive cells than control cultures, but this increase was accompanied by induction of rhodopsin expression, with concomitant decreases in levels of green cone pigment mRNA. No significant differences were found between CNTF- or staurosporine-treated cultures and the corresponding control cultures regarding the red cone pigment, which was expressed in all cases, and the blue and violet pigments, which were not detected in any of the samples. CONCLUSIONS: The results suggest that multiple regulatory systems control visual pigment expression during differentiation of chick embryo photoreceptor cells. CNTF appears to stimulate specifically the differentiation of green cones, without the previously suggested effects on the differentiation of rod photoreceptors in ED 8 chick retinal cultures.

Animals↗

PubMed2000

Laser-assisted percutaneous endoscopic neurolysis.

Endoscopic lysis of adhesive scar utilizing a steerable fiberoptic scope is currently being performed by a growing number of physicians. Various techniques and medications are presently being used to lyse epidural adhesions as a way of improving refractory lumbar radiculopathies. We present a case report discussing laser-assisted endoscopic lysis with radiographic images before and after laser-assisted neurolysis. We were able to demonstrate improvement in the filling of the nerve root with epidural contrast after the laser lysis of scar. This correlated with improvement in pain without neurologic deficit. The laser may represent a useful adjunct in the treatment of pain due to epidural fibrosis.

Journal Article↗

PubMed1999

Cell death in age-related macular degeneration.

The cellular and molecular mechanisms underlying the death of photoreceptors and other retinal cells in age-related macular degeneration (AMD) remain poorly understood. Some of the questions for which answers need to be sought, and which are explicitly or implicitly addressed in this article include: (1) how do patterns of cell death in AMD compare, qualitatively and quantitatively, with "normal" cell death in aging retinas, and with cell death in retinitis pigmentosa (RP) and its animal models; (2) is apoptosis involved in AMD; (3) is there any evidence that rods are necessary for cone survival; (4) if the answer is yes, is there evidence that rods produce one or more survival-promoting factor(s) that act directly on cones; (5) are the effects of rods upon cones exclusively mediated by diffusible factors, or do they also involve contact-mediated interactions; (6) is there any evidence that photoreceptors regulate the survival and/or function of RPE and Müller cells, as well as the interactions between these cells and cones; (7) are trophic factors and their receptors in the macula different from those in other parts of the retina; and (8) are toxic mechanisms involved in the onset and progression of cell death in AMD? Clear cut answers to most of these (and related) questions about cell death in AMD are not yet available. The goal of this article is to summarize discussion that should help in the formulation of suitable hypotheses, amenable to experimental analysis. To provide a platform for such discussion, we present an overview of progress made in recent years in the analysis of other retinal degenerations and of neuronal degenerations in other regions of the CNS. We conclude with an overview of concepts and speculation derived from our current research.

Aging↗

PubMed1999

Activin family members in the developing chick retina: expression patterns, protein distribution, and in vitro effects.

We have investigated whether the activin family of growth factors is involved in the regulation of retinal cell differentiation. Immunocytochemistry and in situ hybridization have shown that activin/inhibin subunits alpha, betaA, and betaB; receptors II and IIB; follistatin; and a follistatin-like gene are expressed in different regions of the chick embryo retina in developmentally regulated patterns. When tested in dissociated retinal cultures, activin did not appear to affect cell survival or proliferation, but it exerted marked inhibitory effects on the differentiation of photoreceptors, while stimulating the differentiation of nonphotoreceptor neurons; both effects were concentration-dependent and follistatin-sensitive. The results are consistent with the possibility that activin family members play significant roles in the regulation of retinal development.

Activin Receptors↗

PubMed1999

Comparison of immunogenicity of two hepatitis A vaccines--VAQTA and HAVRIX--in young adults.

Two new hepatitis A vaccines have been developed, and their immunogenicity tested using different immunoassays. The present study was designed to compare the immunogenicity of these two hepatitis A virus (HAV) vaccines--VAQTA and HAVRIX--as determined by seroconversion rates and anti-HAV titers, and using the same immunoassay. Healthy volunteers (15-30 y), seronegative for anti-HAV, were randomized in an open single center study to four groups of 20-21 vaccinees each, to receive either a 25 U or a 50 U dose of VAQTA, or HAVRIX at 720 EU or 1440 EU/dose, administered at 0, 1 and 6 m or at 0 and 6 m, respectively. Four weeks after primary immunization, seroconversion rates were 100% for VAQTA and 95% for HAVRIX, following injection of 50 U or 1440 EU, respectively (p = NS) and anti-HAV GMTs were 40 and 37 mIU/ml for VAQTA and HAVRIX, respectively. At 6 months, prior to the booster dose, seroconversion rates were 100% for both vaccines, with anti-HAV GMTs of 111 and 70 mIU/ml for VAQTA and HAVRIX, respectively (P < 0.05). At month 7, four weeks after the only booster injection, using the two dose regimen, anti-HAV titers were 2212 and 1511 mIU/ml for VAQTA and HAVRIX, respectively (P < NS). Using three doses of 25 U/dose of VAQTA or 720 EU/dose of HAVRIX at 0, 1 and 6 m did not produce any clinically evaluable advantage over the two dose regimen for either vaccine. No significant adverse events were observed using either vaccine. In summary, both vaccines have similar immunogenicity demonstrated using identical immunoassays for evaluation. These results also confirm the outstanding immunogenicity of a single dose of either of the HAV vaccines and support their use in pre- and possibly postexposure prophylaxis against hepatitis A virus infection.

Adolescent↗

PubMed1999

Comparison of immune reactivity and pharmacokinetics of two hepatitis B immune globulins in patients after liver transplantation.

Hepatitis B virus (HBV) immune globulin (HBIg) administration will prevent HBV graft reinfection in HBV patients after orthotopic liver transplantation (OLT). However, the expenditure for such prophylaxis is extremely high ranging between $2,000 to $10,000 per month in various countries for an undefined period and presumably for life. As a consequence, there is a need for introduction of additional and less expensive modes of treatment. In a preliminary clinical trial a new HBIg preparation has been shown to induce longer lasting levels of circulating antibodies to hepatitis B surface antigen (anti-HBs) in patients after OLT compared with previous experience with conventional HBIg preparations. In the present study the pharmacokinetics of this new HBIg, OMRI-Hep-B, were studied and compared with a conventional, licensed preparation, Hepatect. Fifteen post-OLT patients (2-8 years post-OLT, 18-62 years of age, 6 men, 9 women) were treated intravenously with 49 doses of OMRI-Hep-B or Hepatect given at least once, alternately, at 10,000 to 14,000 units per injection ( approximately 130 IU/kg body weight). The new HBIg was well tolerated and no adverse effects were observed. Administration of OMRI-Hep-B was shown to induce high and long-lasting levels of circulating anti-HBs antibodies and greater areas under the curve (AUC) compared with the conventional preparation. Thus, anti-HBs half-life was 22 +/- 1.3 days for OMRI-Hep-B recipients and 13 +/- 1.3 days for Hepatect recipients (P <.001). Time to reach trough anti-HBs levels of 150 mIU/mL was significantly longer after administration of OMRI-Hep-B than after Hepatect (79 +/- 4.5 and 52 +/- 3.8 days, respectively; P <.001). In summary, the pharmacokinetic profile of the new HBIg, and in particular its prolonged elimination half-life, may reduce the cost of administration by approximately 30% and improve the quality of life of patients by extending the interval between repeated immune globulin injections.

Adolescent↗

PubMed1999

Chronic pain in Holocaust survivors.

There is limited research on the connection between the Holocaust and chronic pain, despite evidence suggesting that medical and psychological sequelae are common in survivors. The goals of this study were: (1) to define Holocaust survivors' (n = 33) chronic pain characteristics as manifested 50 years after the war, (2) to compare survivors with controls (n = 33) who did not experience World War II atrocities, and (3) to investigate the connection between past trauma and chronic pain. Data were collected through questionnaires that included a detailed medical and pain history, visual analog scale (VAS), McGill Pain Questionnaire (MPQ), Beck Depression Inventory (BDI), Symptom Check List-90 (SCL-90), and Pain Disability Index (PDI). A comparison of variables between the two groups was conducted using multivariate analysis of variance (MANOVA) and ANOVA, and canonical discriminant analysis. Results showed that Holocaust survivors reported higher pain levels (73 +/- 18 vs. 56 +/- 21; P < 0.005), more pain sites (4.5 6 2.8 vs. 2.7 6 1.4; P < 0.05), and significantly higher depression scores (17.6 +/- 8.4 vs. 9.2 +/- 4.6; P < 0.001); they tended to utilize more medical services (5.9 +/- 3.0 vs. 5.1 +/- 2.8). Nonetheless, survivors did not regard themselves more disabled as compared with controls. They reported a higher activity level as measured by walking distance capacity, and spent significantly fewer hours resting (4.3 +/- 3.6 vs. 7 +/- 4.6; P < 0.05). This paradoxical combination of high pain intensity, moderate to severe depression, and high activity level characterizes Holocaust survivors' chronic pain. It is conceivable that by remaining active Holocaust survivors fight back their pain, distress, and depression. These findings suggest that Holocaust atrocities affect survivors' chronic pain even years later.

Aged↗

PubMed1999

Thalamic stimulation in patients with multiple sclerosis.

OBJECTIVE: To assess tremor control and side effects in patients with multiple sclerosis (MS) treated with chronic thalamic stimulation for relief of upper extremity tremor. METHODS: Five patients were studied before and after thalamic placement of a deep brain stimulation (DBS) system. Preoperative and postoperative evaluation included magnetic resonance imaging, Extended Disability Status Scale (EDSS), the Bain-Finchley visual analog scale for tremor, video recording and neuropsychological testing. Stereotactic targeting of the Vim nucleus was done using computed tomography; intraoperative testing was done under local anesthesia before permanent implantation. RESULTS: Functionally useful tremor suppression was obtained in 3/5 patients. Neuropsychological deficits of higher cortical function, memory and visuospatial coordination were observed in all patients before surgery; in 1 patient with improved postoperative visuospatial coordination, worsened memory was found. New brainstem plaque formation was seen several weeks after surgery in 1 patient who had an acute worsening of MS which improved after high-dose intravenous steroids. CONCLUSIONS: Chronic thalamic stimulation may help selected patients with MS-induced tremor. Given the complexity of their underlying illness, patients must be selected carefully, and long-term follow-up is vital to evaluate the true utility of DBS.

Adult↗

PubMed1999

Varicella complicated by group A streptococcal sepsis and osteonecrosis.

A 5-year-old boy presented with primary varicella zoster virus infection, group A streptococcal sepsis, toxic shock, and multisite osteonecrosis. An association between osteonecrosis and group A streptococcal sepsis has not been previously reported. Clinical recognition with supportive radiologic and pathologic findings are presented. Therapeutic guidelines are suggested.

Bacteremia↗

PubMed1998

Developmental neuronal death is not a universal phenomenon among cell types in the chick embryo retina.

The goal of this study was to investigate whether all the cell types present in the chick embryo retina undergo developmental neuronal death. Apoptosis was investigated in retinal sections at different developmental stages, processed either with propidium iodide, which stains pyknotic nuclei intensely, or with terminal transferase-mediated deoxyuridine triphosphate (d-UTP)-biotin nick-end labeling (TUNEL). Internucleosomal DNA fragmentation was investigated in tissue extracts by agarose gel electrophoresis. TUNEL-positive (T+) cells and pyknotic nuclei were first detectable in the ganglion cell layer (GCL) around embryonic day (ED) 8 and peaked at ED 10. In the inner nuclear layer (INL), T+ and pyknotic cells first appeared on ED 8, reached maximum frequency on ED 11, and were largely absent after ED 14. DNA ladders were observed at all the stages, when T+ and pyknotic cells were abundant, but not on ED 4, when only scattered dead cells were observed histologically. Dying cells were virtually never detected in the outer nuclear layer (ONL) from ED 4 to postnatal day 2. After unilateral midbrain ablation on ED 5, there was a striking increase in the number of pyknotic and T+ cells in both the GCL and in the INL of the contralateral eye but not in the ONL. The absence of apoptotic cell death in the ONL during normal development and after tectal ablation shows that developmental death is not universal among the various cell populations present in the chick embryo retina and raises questions regarding mechanisms controlling both photoreceptor survival and the matching of pre- and postsynaptic elements in the outer plexiform layer of this species.

Animals↗

PubMed1998

The NMDA receptor antagonist amantadine reduces surgical neuropathic pain in cancer patients: a double blind, randomized, placebo controlled trial.

Neuropathic pain is often severe, persistent, and responds poorly to analgesic medications. Recent evidence suggests that N-methyl-D-aspartate (NMDA) receptor antagonists may be effective in the treatment of neuropathic pain. The present trial was designed to test the efficacy of acute administration of the NMDA receptor antagonist amantadine in relieving surgical neuropathic pain in patients with cancer. The study sample consisted of 15 cancer patients with the diagnosis of surgical neuropathic pain. Two 500 ml infusions of either 200 mg amantadine or placebo were administered over a 3 h period, in a randomized order, 1 week apart from each other. Spontaneous and evoked pain were measured for 48 h before treatment, during treatment, and for 48 h following treatment. An average pain reduction of 85% was recorded at the end of amantadine infusion vs. 45% following placebo administration. The difference in pain relief between the two treatments was statistically significant (P = 0.009). Mean pain intensity remained significantly lower during the 48 h following amantadine treatment as compared with the 48 h prior to treatment (31% reduction; P = 0.006), whereas no such effect was found with the placebo (6% reduction; P = 0.40). Amantadine, but not the placebo, also reduced 'wind up' like pain (caused by repeated pinpricking) in four patients. We conclude that amantadine infusion is a safe and effective acute treatment for surgical neuropathic pain in cancer patients. Further trials with long-term oral or parenteral amantadine treatment should be conducted.

Adult↗

PubMed1998

Neurological complaints after unsuccessful spinal anaesthesia as a manifestation of incipient syringomyelia.

The medical literature sometimes reports neurological complications after spinal or epidural anaesthesia. In a few cases, the onset of symptoms can be a sign of a pre-existing disease without a primary connection with regional anaesthesia. In the following case report, the patient complained of paraesthesias in both legs after a failed spinal anaesthesia, even though the needle had been placed intrathecally. Only neurological examination and nuclear magnetic resonance imaging revealed the presence of syringomyelia.

Aged↗

PubMed1998

Preschool behaviour problems in a multicultural Australian urban area.

OBJECTIVE: This paper reports on a survey of behaviour problems in a sample of 4-year-old preschoolers from the western suburbs of metropolitan Melbourne. This region consists of a diverse multicultural population and families from lower socio-economic status (SES) backgrounds. METHODOLOGY: Nineteen preschools participated in the study and information was obtained for 743 preschool children (Refer to MS) age=4.7 years). Parents were asked to complete the Preschool Behaviour Questionnaire (PBQ) and additional questions referring to demographic and family information. Teachers were also asked to complete the PBQ on each of the children. Three factors were extracted from the PBQ (anxious-fearful, hostile-aggressive, hyperactive), and also a combined externalising behaviours factor. RESULTS AND CONCLUSIONS: Findings indicated lower levels of behaviour problems in this sample compared to that of other Australian studies. Boys showed higher rates of externalising behaviour problems than girls. The relationships between behaviour problems and language difficulties, ethnicity, and socio-economic status are discussed.

Australia↗