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Biomedical subjects

R D Harris

Publications and source records attributed to R D Harris.

At least 37 records · Page 2Linked to original sources
PubMed1997

Managing successful construction and renovation projects.

If you are the lead person during a project, it is your responsibility to follow-up on every detail and task involved to guarantee overall success. Team members look to you as the example and as the communicator. Although other people may fail to accomplish their tasks, you must have the ability and energy to push the issue to completion without losing your cool or throwing your hands up. Projects usually require the coordination of multiple issues, tasks, and personnel. The process can be rewarding, or it can be your worst nightmare. Make it fun, but keep it organized. Communicate properly, and design each project process to fit the project needs.

Building Codes↗
PubMed1996

Sonography of the placenta with emphasis on pathological correlation.

The placenta is a most interesting but unfortunately often ignored and misunderstood organ. Included in its many functions are fetal oxygenation and nutrition as well as a myriad of endocrinological contributions and protein synthesis. The sonologist is strongly encouraged to study this amazing structure with ultrasound because significant pathology afflicts the placenta, often before affecting the fetus. Placental abnormalities, therefore, can be an "early warning system" for fetal problems. Recognition of clinically important lesions (abruption, accreta) as well as important anatomical variants (intervillous thrombosis, septal cyst) is crucial for the physician who performs and interprets prenatal ultrasound. This article discusses the common abnormalities of the placenta and highlights some correlative pathological processes, which will serve to enhance the reader's understanding of sonographic findings. A practical approach is presented with respect to assessment of the hypoechoic lesion, placental infarction, thick placenta, placenta previa, abruption, placenta accreta, and placental tumors.

Female↗
PubMed1996

Tissue-shrinkage correction factor in the calculation of prostate cancer volume.

Many studies that have calculated prostate cancer volumes from microscopic slides have used correction factors, ranging from 1.22 to 1.5, to compensate for tissue shrinkage during tissue processing. We undertook a study to measure tissue shrinkage directly because our experience suggested less shrinkage than that reported by others. Ten prostatectomy specimens were processed in a uniform manner. Multiple identical linear measurements were taken at four stages of processing: in the fresh state, following fixation, following processing, and from the microscopic slide. Linear shrinkage following fixation was minimal (4.1%) but increased to 14.5% following tissue processing. With rehydration and expansion on the flotation bath, tissues swelled so that net linear tissue shrinkage was 4.3%, and net volumetric tissue shrinkage was 12.4%, which translates into a correction factor for tissue shrinkage of 1.14. The following variables had no statistically significant effect on shrinkage: concentration of formalin, whole-mount versus quadrant sections, thickness of tissue slices, length of time in the alcohol dehydration steps, and temperature of the flotation bath over a range of 35 to 45 degrees C. This study suggests that (a) tissue-shrinkage correction factors that have been used in some previous studies may not be applicable for all laboratories because of interlaboratory variations in tissue-processing procedures or differences in measuring shrinkage; and (b) some calculated tumor volumes that have been used for prognostic thresholds may be high because of inflated tissue-shrinkage correction factors.

Humans↗
PubMed1995

Arytenoid sparing during irradiation of early stage vocal cord cancer.

PURPOSE: Optimal position of the posterior field border when irradiating early stage vocal cord cancer is controversial. Several experts recommend moving the posterior field border 5-15 mm anteriorly after 50-60 Gy to decrease the chance of arytenoid edema. This article will evaluate the effect of field position on arytenoid dose. METHODS AND MATERIALS: 5 x 5 cm opposed lateral fields centered on the glottis were set up on a patient with typical anatomy. Isodose profiles were obtained with equally weighted 6 MV photon beams attenuated with 15 degree wedge filters using contours from an axial CT scan. Profiles with the posterior field border overlaying, 5, and 10 mm posterior to the posterior edge of the thyroid cartilage are presented. RESULTS: With the posterior field border 10 mm posterior to the thyroid cartilage, the arytenoids are included in the 95% isodose volume. Reducing the field by 5 mm has no significant effect on the position of the 95 and 90% isodose lines relative to the arytenoids. A field reduction of 10 mm places the arytenoids in the beam penumbra and leaves approximately 10 mm between the 95% isodose line and the midpoint of the true vocal cord. CONCLUSION: To achieve a significant dose differential between the arytenoids and the anterior portion of the vocal cord when using opposed lateral 6 MV photon beams the posterior field border must be at, or anterior to, the posterior edge of the thyroid cartilage. In view of the excellent results reported from institutions that include the arytenoids in the high-dose volume throughout treatment, it would seem appropriate to limit the use of arytenoid-sparing techniques to patients in whom there is no ambiguity about tumor location and in whom the treatment setup is very reproducible.

Arytenoid Cartilage↗
PubMed1995

Virilization during pregnancy with spontaneous resolution postpartum: a case report and review of the English literature.

The incidence of gestational hyperandrogenism secondary to ovarian pathology is low. However, when the condition does exist, diagnosis should be made with minimally invasive modalities. It is important to provide appropriate medical/surgical intervention without disturbing the pregnancy iatrogenically or causing unnecessary maternal morbidity. This case report adds to the existing radiographic data concerning this rare obstetrical condition. Presented is a review of the English literature on virilizing ovarian tumors during pregnancy, and a discussion of an approach to managing these tumors when they occur during pregnancy.

Adult↗
PubMed1995

Staging of prostate cancer with endorectal MR imaging: lessons from a learning curve.

Endorectal magnetic resonance (MR) imaging is the most accurate noninvasive method of staging prostate cancer. However, inexperienced radiologists may lack the necessary technical and interpretative skills to use this technique, and both radiologists and referring urologists may become frustrated with this method because of its inaccuracy compared with analysis of the radical prostatectomy specimen. Meticulous pathologic correlation is necessary to evaluate endorectal MR imaging findings. The authors compare their initial experience using endorectal MR imaging for staging prostate cancer (25 cases) with their later experience (25 cases) to highlight the various diagnostic pitfalls and "pearls" one may encounter when using endorectal MR imaging. Knowledge of the pathways of tumor spread inside and outside the gland may be helpful in interpreting endorectal MR images. The authors achieved a substantial improvement in the overall staging accuracy of endorectal MR imaging by careful pathologic correlation and by considering the anatomic features of prostate cancer.

Case-Control Studies↗
PubMed1995

Environment of care. Organize to find your way through the maze.

The Environment of Care and the Orientation, Training, and Education sections of the JCAHO manual will be important parts of the 1995 survey process. All departments must be able to describe their role in both programs, as well as demonstrate compliance with them. Staff knowledge of the two programs is also critical since 40-50% of the survey process will be devoted to asking staff members questions concerning their role in each of the two programs. Organizing the manual as described will force you to examine each section closely. As each section is completed, you will accomplish two goals. First, you have complied with the requirements because you have developed departmental programs geared towards EOC. Second, by developing these sections, you have created a basic training outline for your staff. If you organize and gather the data described in this article, the development of your training programs will be much easier. Most of you have all of the tools required to comply with both programs, but by organizing them in an efficient and orderly fashion, you will assure yourself a much easier time complying with the new EOC standards.

Health Personnel↗
PubMed1994

Nanometric design of extraordinary hydrophobic-induced pKa shifts for aspartic acid: relevance to protein mechanisms.

Commonly a key element enabling proteins to function is an amino acid residue or residues with functional side chains having shifted pKa values. This article reports the results on a set of protein-based polymers (model proteins) that exhibit hydrophobic folding and assembly transitions, and that have been designed for the purpose of achieving large hydrophobic-induced pKa shifts by selectively replacing Val residues by Phe residues. The high molecular weight polypentapeptides, actually poly(tricosapeptides) with six varied pentamers in fixed sequence, were designed and synthesized to have the same amino acid compositions but different proximities between a single aspartic acid residue and 5 Phe residues per 30 residues. With the 5 Phe residues distal from the Asp residue, the observed pKa shift was 2.9 when compared to the Val-containing reference. With the 5 Phe residues within 1 nm of the Asp residue, the pKa shift was 6.2. This represents a free energy of interaction of 8 kcal/mole. To our knowledge, this is the largest pKa shift documented for an Asp residue in a polypeptide- or protein-water system. Data are reviewed that do not support the usual electrostatic arguments for pKa shifts of charge-charge repulsion and/or unfavorable ion self-energies arising from displacement of water by hydrophobic moieties, but rather the data are interpreted to indicate the presence of an apolar-polar repulsive free energy of hydration, which results from a potentially highly cooperative competition between apolar and polar species for hydration.

Amino Acid Sequence↗