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Biomedical subjects

L Roberts

Publications and source records attributed to L Roberts.

At least 397 records · Page 22Linked to original sources
PubMedDate not supplied

Diagnosing sinusitis by X-ray: is a single Waters view adequate?

OBJECTIVE: To determine whether a single Waters view (occipito-mental) radiograph could be substituted for a four-view sinus series to diagnose sinusitis, and to determine the inter- and intraobserver variabilities for sinus radiography. DESIGN: Radiographs were interpreted by radiologists blinded to the clinical history, and results were recorded on a standardized form. SETTING: Veterans Affairs Medical Center. PARTICIPANTS: Staff attending radiologists, an attending radiologist with special training in skull radiology, and a senior radiology resident. MEASUREMENTS AND MAIN RESULTS: The agreement between the Waters view and the four-view sinus series was moderate to substantial (simple agreement = 75-84%, kappa = 0.5-0.68). However, agreement varied by sinus and, after correction for chance agreement, was substantial only for the maxillary sinuses (kappa = 0.72-0.87). Intraobserver agreement (kappa = 0.72-0.84) was superior to interobserver agreement (kappa = 0.49-0.59) for the four-view sinus series. CONCLUSIONS: Substituting a single Waters view for a four-view sinus series may be an acceptable strategy for diagnosing maxillary sinusitis.

Adult↗
PubMedDate not supplied

Computed tomography in the evaluation of severe facial trauma.

Computed tomography (CT) is a simple, rapid, and safe method of evaluating patients with severe facial trauma. It has its greatest value in defining the extent of soft tissue damage as well as in assessing the skeletal disruption. In a group of 32 patients with severe facial trauma, CT outlined the degree of soft tissue and skeletal fracture. In 13 of these patients who also underwent conventional pleuri-directional tomography CT was determined to be just as effective in identifying all fractures. CT was also shown to be useful for follow up evaluation of patients with previous severe facial trauma.

Facial Injuries↗
PubMedDate not supplied

An unusual presentation of thyroid papillary carcinoma: enlargement of a cervical intervertebral foramen.

Isolated enlargement of the cervical intervertebral foramen is frequently associated with dumbbell neurogenic tumors. We present an unusual case of isolated enlargement of a cervical intervertebral foramen in a 77-year-old male with an aggressive papillary thyroid carcinoma. To our knowledge, this represents the first case describing a thyroid process as a cause of foraminal enlargement.

Aged↗
PubMedDate not supplied

Developmental toxicity evaluation of unleaded gasoline vapor in the rat.

To evaluate the potential of unleaded gasoline vapor for developmental toxicity, a sample was prepared by slowly heating API 94-02 (1990 industry average gasoline) and condensing the vapor. The composition of this vapor condensate, which comprises 10.4% by volume of the starting gasoline, is representative of real-world exposure to gasoline vapor encountered at service stations and other occupational settings and consists primarily of volatile short chain (C4-C6) aliphatic hydrocarbons (i.e. paraffins) with small amounts of cycloparaffins and aromatic hydrocarbons. A preliminary study in rats and mice resulted in no developmental toxicity in either species. However, a slight reduction in maternal body weight gain in rats led to the selection of rats for this guideline study. Groups of pregnant rats (n = 24/group) were exposed to unleaded gasoline vapor at concentrations of 0, 1000, 3000, or 9000 (75% lower explosive limit) ppm equivalent to 0, 2653, 7960, or 23,900 mg/m3, for 6 h/day on gestation days 6-19. All rats were sacrificed on gestation day 20. No maternal toxicity was observed. Developmentally, there were no differences between treated and control groups in malformations, total variations, resorptions, fetal body weight, or viability. The maternal and developmental NOAEL is 9000 ppm. Under conditions of this study, unleaded gasoline vapors did not produce evidence of developmental toxicity.

Administration, Inhalation↗
PubMedDate not supplied

Generation of a potent chimeric toxin by replacement of domain III of Pseudomonas exotoxin with ricin A chain KDEL.

Following cellular uptake, Pseudomonas exotoxin (PE) is cleaved by cellular protease which generates an enzymatically active C-terminal fragment (amino acids 280-613). This 37 kD fragment translocates to the cell cytosol where it ADP-ribosylates elongation factor 2 and inhibits protein synthesis. A recombinant hybrid toxin (designated PE-RTA) in which the ADP-ribosylation domain (domain 111) was replaced by the RNA N-glycosidase domain of ricin (the A chain or RTA) has been produced in E. coli. The hybrid toxin effectively and specifically depurinated 28S ribosomal RNA, indicating that the ricin A moiety folded into its native conformation. The cytotoxicity of PE-RTA for L929 cells was approximately 100-fold less than either native PE or whole ricin. However, the addition of the tetrapeptide KDEL to the C-terminus of PE-RTA (producing PE-RTA KDEL) increased cytotoxicity to the level of the native toxins. By analogy to PE, both PE-RTA and PE-RTA KDEL would be proteolytically cleaved within PE domain II during cell entry. A single amino acid substitution, believed to disrupt an essential step in the transport of the catalytically active PE fragment to the cell cytosol (Trp281 to Ala: Zdanovsky, A.G., Chiron, M., Pastan, I., and FitzGerald, D. J. (1993) J. Biol. Chem. 268, 21791-21799), reduced the cytotoxicities of both PE and PE-RTA KDEL by approximately 100-fold. Taken together, these data show that the ricin A chain component of the hybrid toxin requires essential PE-derived sequences at both the N- and C-termini of the translocating fragment. Clearly, in the context of this fusion protein, ricin A chain cannot effect its own transfer to the cytosol.

ADP Ribose Transferases↗
PubMedDate not supplied

Short communication: trophoblast proliferation is increased in chorionic villi from pregnancies with fetal trisomy 18.

Pregnancies with fetal trisomy 18 suffer from severe intrauterine growth restriction from the first trimester. This cross-sectional study of chorionic villi obtained from ongoing singleton pregnancies at 10-14 weeks of gestation, semiquantitatively examines chorionic villus stromal and trophoblastic cell proliferation rates in ongoing chromosomally normal and trisomy 18 pregnancies. Chorionic villi were stained using a standard immunohistochemistry protocol with a monoclonal antibody to the Ki-67 antigen and the number of Ki-67 positive trophoblastic and stromal cells per villous cross-section was compared between groups. The number of Ki-67 positive trophoblastic and stromal cells was significantly higher in the group (n=10) with trisomy 18 compared to the chromosomally normal group (n=25;t=2.1, P=0.03 and t=5.3, P<0.001 respectively). Abnormalities in control of cell turnover during development may be important in the pathogenesis of the clinical features of trisomic pregnancies.

Adult↗
PubMedDate not supplied

Red blood cell alkalosis and decreased oxyhemoglobin affinity.

The behavior of the oxyhemoglobin curve was studied in ten patients with respiratory alkalosis (arterial [H+] less than 37 nM, pCO2 less than 32 mmHg and HCO-3 less than 22.0 mEq/L) and ten patients with metabolic alkalosis ([H+] less than 34 nM, pCO2 greater than 37 mmHg and HCO-3 greater than 28.0 mEq/L) to determine whether different alkalotic states similarly affect the red blood cell [H+] and 2,3-diphosphoglycerate interaction and thus the oxygen affinity of hemoglobin. The findings were statistically indistinguishable in respiratory alkalosis and metabolic alkalosis: a) low plasma [H+], normal red blood cell [H+], and high transmembrane [H+] gradient; b) elevated red blood cell 2,3-diphosphoglycerate inversely proportional to low arterial plasma [H+]; c) decrease in oxygen affinity of hemoglobin when normalized for plasma [H+], but less decreased when normalized for red blood cell [H+]. Other factors capable of affecting the oxygen affinity of hemoglobin were: mean corpuscular hemoglobin concentration; red blood cell adenosine triphosphate; carboxyhemoglobin; and methemoglobin were not significantly different between groups. These results: 1) agree with data previously reported from this laboratory on patients with portal-systemic encephalopathy; 2) underscore the importance of RBC [H+] in defining the oxygen affinity of hemoglobin; 3) suggest the decrease in oxygen affinity of hemoglobin is mediated through the 2,3-diphosphoglycerate elevation; and 4) indicate the high transmembrane [H+] gradient is principally due to the cellular accumulation of [H+] (2,3-diphosphoglycerate ionization).

2,3-Diphosphoglycerate↗
PubMedDate not supplied

Analysis of materials for splinting of the thermally injured patient.

Good results have been achieved in the treatment of patients with burns with new splinting materials and proper splinting techniques. This article focuses on the thermoplastic splinting materials Clinic and Spectrum (Northcoast Medical Inc., San Jose, Calif.) and the comparable thermoplastic products Polyform (Smith & Nephew Rolyan, Inc., Menomonee Falls, Wis.) and Orthoplast (Johnson & Johnson Orthopedics, New Brunswick, N.J.). Qualities such as self-bonding, recyclability, and rigidity were tested for these materials. Splint rigidity was measured by a calibrated hook scale and determined by the force per pound needed to bend the material 20 degrees. Spectrum and Clinic products were judged more economical and, we contend, they are therefore better choices for splinting the thermally injured patient.

Burns↗
PubMedDate not supplied

Longitudinal hand grip and pinch strength recovery in the child with burns.

Hand strength of seven patients was evaluated prospectively. A range-of-motion exercise program, compression therapy, and splinting schedules were provided. Fine prehension; lateral, tip-to-tip, and tripod pinch were measured by pinch meter. Grip strength was measured by dynamometer. Comparisons were made between test strengths and published norms for age and sex with analysis of variance. Significance was accepted at p < 0.05. At discharge, all four strength measurements were significantly less than normal for age and sex. Grip and tripod strengths were improved by 6 weeks. All measurements were improved at 6 months after discharge, although grip and lateral pinch remained significantly less than norms. In conclusion, the measurements of tip-to-tip and tripod pinch at 6 months may not signify limitations in performance of activities of daily living. In spite of significantly lower than normal grip and lateral strength measurements at 6 months, it cannot be determined whether this hinders performance of daily living skills.

Burns↗
PubMedDate not supplied

Elder abuse: raising the awareness of nurses working in A & E units.

Despite a growing literature, many professionals have a limited knowledge of elder abuse. This article highlights some of the conceptual and practical problems surrounding the topic in order to raise awareness and provide some indication of the nurse's role.

Aged↗
PubMedDate not supplied

Promoting reduced smoking rates in the context of workplace smoking bans.

A randomized study was conducted in 41 workplaces to determine the potential of self-help and group-based programs to encourage reduced smoking in workplaces that have implemented smoking bans. The trial had limited success in recruiting smokers, attrition was an important limitation, and the study outcomes were modest. The authors conclude that more research is needed on effective strategies that help smokers minimize smoking at work.

Adult↗
PubMedDate not supplied

Birth center outcomes reported through automated technology.

UNLABELLED: BirthCare HealthCare is a multidisciplinary health care clinic and freestanding birth center in Salt Lake City, Utah. Highlights of a woman's labor assessment and birth outcomes are summarized in a paper birth log. The authors developed a relational database that facilitates efficient outcomes reporting. Examples of outcomes from this database are reported. OBJECTIVES: This study describes clinical outcomes from a freestanding birth center and the automated birth log database used to manage outcomes reporting. DESIGN: Retrospective data obtained primarily from a paper birth log and secondarily from the paper chart were entered into and extracted from an electronic database. PARTICIPANTS: 231 women who were evaluated in 269 encounters for delivery at the birth center between July 1, 1997, and June 30, 1999. MAIN CLINICAL OUTCOME MEASURES: The number of deliveries at the birth center; the percentage of intrapartum, postpartum, and newborn transfers to the inpatient hospital setting; cause-specific transfer rates; method of transfer; medication in labor; low and high birth weights; percentage of low Apgar scores; and average times from admission to birth and birth to discharge. CONCLUSION: Birth center clinical outcomes can be efficiently reported using an automated birth log. Clinical outcomes reported in this study are consistent with finding of previous research that demonstrates that birth centers are a safe alternative site for delivery.

Birth Weight↗
PubMedDate not supplied

Diabetes mellitus and Klebsiella pneumoniae liver abscess in adults.

Klebsiella pneumoniae hepatic abscess in five diabetic patients is reported. The recognition of a possible association between diabetes mellitus and pyogenic hepatic abscess, especially solitary ones, is highlighted. The clinical presentation including metastatic complications and the need for early diagnosis and institution of therapy are emphasized. Needle aspiration under ultrasonography is advocated and culture for anaerobes is stressed.

Adult↗