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Biomedical subjects

R F Green

Publications and source records attributed to R F Green.

At least 19 recordsLinked to original sources
PubMed2001

Resolving the structure of ionized helium in the intergalactic medium with the far ultraviolet spectroscopic explorer.

The neutral hydrogen (H I) and ionized helium (He II) absorption in the spectra of quasars are unique probes of structure in the early universe. We present Far-Ultraviolet Spectroscopic Explorer observations of the line of sight to the quasar HE2347-4342 in the 1000 to 1187 angstrom band at a resolving power of 15,000. We resolve the He II Lyman alpha (Lyalpha) absorption as a discrete forest of absorption lines in the redshift range 2.3 to 2.7. About 50 percent of these features have H I counterparts with column densities N(H I) > 10(12.3) per square centimeter that account for most of the observed opacity in He II Lyalpha. The He II to H I column density ratio ranges from 1 to >1000, with an average of approximately 80. Ratios of <100 are consistent with photoionization of the absorbing gas by a hard ionizing spectrum resulting from the integrated light of quasars, but ratios of >100 in many locations indicate additional contributions from starburst galaxies or heavily filtered quasar radiation. The presence of He II Lyalpha absorbers with no H I counterparts indicates that structure is present even in low-density regions, consistent with theoretical predictions of structure formation through gravitational instability.

Journal Article↗
PubMed1997

Utilization of intraoperative electroneurography to understand the innervation of the trapezius muscle.

The radical neck dissection is an operation for the management of lymph node metastases from primary sites involving the oral cavity, larynx, and other areas of the head and neck. In this procedure, the spinal accessory nerve is removed along with other structures. In modified neck dissection the spinal accessory nerve is preserved. Patients undergoing the modified neck dissection have had variable functional outcomes from little or no pain or disability, to significant muscle dysfunction. Our group hypothesized that patients with good functional outcomes following modified neck dissection may have had motor contributions from C2, C3, or C4 branches, while those with less favorable outcomes did not. To demonstrate the presence of motor input and its significance both from the spinal accessory nerve and the branches of the cervical plexus, we utilized intraoperative electroneurography. We find that although there is motor contribution from C2, C3, and C4 to the trapezius muscle, it was not consistent or significant.

Cervical Plexus↗
PubMed1995

The impact of environmental turbulence on American hospital strategies.

It is clear that dramatic changes are taking place in the way health care organizations are being managed. Health care executives are having to make the transition from managing with a "pass the cost along to the consumer" perspective to one of extreme competitive pressure to reduce costs while maintaining appropriate levels of quality. Reports the results of a survey of 135 American hospitals' executives. Uses factor analysis to uncover four distinct strategies being operationalized. Classifies hospitals' strategies as: strategic analysers, externally focused and offensively proactive; quality providers, internally-focused and defensive reactors; price negotiators, externally-focused and offensively reactive; or cost efficiency providers, internally focused and defensively proactive.

Cost-Benefit Analysis↗
PubMed1995

Continuous improvement and TQM in health care: an emerging operational paradigm becomes a strategic imperative.

Argues that US health care is in a state of crisis. Escalating costs account for 13 per cent of GNP, making health care the third largest industry in the USA, and spending is expected to increase. Claims health-care providers need to control rising costs, improve productivity and flexibility, adopt appropriate technologies, and maintain competitive levels of quality and value. States that TQM may provide an environment that will focus on quality of patient care and continuous quality improvement at all levels of the organization including the governing body, the administrative, managerial, and clinical areas. Any new national or state health-care plan will force providers to be more efficient while maintaining quality standards. Concludes that it will be strategically imperative that health-care providers ranging from family physicians to major medical centres and suppliers ranging from laboratories to pharmaceutical firms establish methods for making rapid continuous improvement and total quality management the cornerstone of the strategic planning process.

Data Collection↗
PubMed1991

Spinal accessory nerve palsy: an unusual complication of coronary artery bypass.

The neurologic complications of coronary artery bypass surgery have been well documented, with a reported incidence of 61% in one large study. Most injuries to the peripheral nervous system involve the brachial plexus. We report the first case of a spinal accessory nerve lesion after coronary bypass surgery. The patient presented with progressive right shoulder weakness. Electrodiagnostic studies revealed a partial lesion of the right spinal accessory nerve. Physical therapy, including strengthening, range of motion, and electric stimulation to the right shoulder, was prescribed to assist recovery of strength and function. Repeat electrodiagnostic studies confirmed nerve regeneration. Prompt recognition of spinal accessory nerve damage after coronary bypass surgery is essential. Early rehabilitation will improve the chances of a better functional outcome.

Accessory Nerve↗
PubMed1990

Lower extremity weakness as the initial manifestation of lung cancer.

A 55-year-old woman had progressive lower extremity weakness. She had an 80-pack-per-year history of cigarette smoking. Electromyographic findings were consistent with the Lambert-Eaton myasthenic syndrome. Despite a normal chest x-ray, normal laboratory studies, and negative bronchoscopy, investigation for lung cancer was pursued. The final thoracotomy and pathology reports indicated a diagnosis of oat cell carcinoma. After treatment with chemotherapy and radiation therapy, clinical and electrophysiologic findings have resolved. Two years after diagnosis, the patient remains in good health without evidence of recurrence.

Carcinoma, Small Cell↗
PubMed1989

Thrombosis of axillary-femoral bypass secondary to prosthesis suspension belt.

Patients with peripheral vascular disease and lower extremity amputation frequently undergo arterial bypass surgery to salvage the opposite leg. Compression of axillary-femoral bypass grafts can occur from a variety of causes. The primary physician should monitor graft pulses closely. Compression should be avoided by using forearm crutches instead of axillary crutches. Waist belts for prosthetic support should not be used, and alternatives such as a thigh corset or shoulder suspension should be used. The patient should avoid sleeping on the graft, using a wrist restraint when necessary. If the patient gains weight, garments should be adjusted so as not to be constricting. Upper extremity exercises, particularly in should abduction and extension, should not be so vigorous as to put tension on the graft. A 77-year-old woman with a left below-knee amputation underwent an axillary-femoral bypass for right lower extremity arterial insufficiency which subsequently thrombosed due to compression by the waist belt of her below-knee prosthesis. A series of guidelines are outlined, so that the physiatrist can help maintain graft patency, prolong limb salvage, and avert similar complications in such patients.

Aged↗
PubMed1987

Radiation-induced long thoracic nerve palsy.

The incidence of long thoracic nerve palsy after radical mastectomy has been documented to be approximately 10%. No cases have been reported after the more recent treatment for breast cancer, lumpectomy with axillary dissection. This more recent surgical procedure is customarily followed by aggressive radiation therapy to the remaining breast tissue. This is the first case report of a patient with radiation-induced long thoracic nerve palsy. The patient was a young woman who underwent left breast quadrantectomy and axillary dissection for breast cancer. After radiation therapy, she had isolated left long thoracic nerve palsy. The diagnosis was confirmed by electrodiagnostic studies. Almost full recovery occurred after 5 months.

Adult↗
PubMed1985

Accessory nerve latency to the middle and lower trapezius.

Trapezius muscle dysfunction occurs following injury to the spinal accessory nerve from a variety of causes. The trapezius consists of three distinct segments: upper, middle, and lower. Since previous studies of accessory nerve latency measure conduction to the upper trapezius segment only, this present study describes a standardized technique for determining accessory nerve latency to the middle and lower trapezius, a particularly important measurement for accurate examination for those who are in pain or unable to cooperate. Mean normal latency in 21 nerves to the middle trapezius is 3.0 +/- 0.2 msec and to the lower trapezius is 4.6 +/- 0.3 msec. Accessory nerve latency measurement of the middle and lower trapezius segments is valuable in a case of surgical injury in the posterior cervical triangle, especially during recovery from accessory nerve injury when reinnervation of the upper segment precedes the middle and lower segments.

Accessory Nerve↗
PubMed1982

Lectin-resistant mutants of polarized epithelial cells.

Two lectin-resistant mutants derived from Madin Darby canine kidney cells, with constitutive alterations in the asparagine-linked carbohydrate moieties, retained the characteristic structural and functional epithelial polarity of the parental cells. A ricin-resistant cell line was unable to incorporate galactose-sialic acid into glycoproteins and, from the pattern of cross-resistance to other lectins, appears to be different from previously described lines resistant to this lectin: the mutation in a concanavalin A-resistant line results, probably, in the production of defective carbohydrate cores of glycoproteins. In spite of glycosylation defects which result in an increased electrophoretic mobility of many cellular glycoproteins, both mutants retained the typical asymmetric structure of the plasma membrane (microvilli on the apical surface, junctional elements on the basolateral surface), functional tight junctions, and unidirectional active transport of electrolytes and water. These results suggest that glycoproteins with terminal galactose-sialic acid moieties are not critically involved in the development and maintenance of polarity in epithelial cells. The mutant cells, particularly the ricin-resistant line, exhibited, however, morphological and electrophysiological changes which suggest a quantitative effect of the mutations on intracellular traffic of membranes and tight junction formation. The cell lines described in this paper, the first lectin-resistant mutants of epithelial lineage, should prove useful tools for studying the peculiarities of glycosylating pathways in polarized cells.

Cell Adhesion↗
PubMed1982

Pneumatic Airleg prosthesis: report of 200 cases.

The pneumatic Airleg is a recently developed prosthetic system for the early mobilization of the patient with lower extremity amputation. It has been used as an alternative for the rigid plaster of paris dressing in immediately postoperative prosthetic fitting and ambulation, and has also been employed as a temporary prosthesis in the total contact weight-bearing ambulation of patients with open or ulcerated amputation stumps. The latter is illustrated by 3 case reports Advantages are ease of application and removal, availability of the amputation site for inspection, and early institution of weight-bearing ambulation with minimal discomfort.

Adult↗
PubMed1981

Glycosylation does not determine segregation of viral envelope proteins in the plasma membrane of epithelial cells.

Enveloped viruses are excellent tools for the study of the biogenesis of epithelial polarity, because they bud asymmetrically from confluent monolayers of epithelial cells and because polarized budding is preceded by the accumulation of envelope proteins exclusively in the plasma membrane regions from which the viruses bud. In this work, three different experimental approaches showed that the carbohydrate moieties do not determine the final surface localization of either influenza (WSN strain) or vesicular stomatitis virus (VSV) envelope proteins in infected Madin-Darby Canine Kidney (MDCK) cells, as determined by immunofluorescence and immunoelectron microscopy, using ferritin as a marker. Infected concanavalin A- and ricin 1-resistant mutants of MDCK cells, with alterations in glycosylation, exhibited surface distributions of viral glycoproteins identical to those of the parental cell line, i.e., influenza envelope proteins were exclusively found in the apical surface, whereas VSV G protein was localized only in the basolateral region. MDCK cells treated with tunicamycin, which abolishes the glycosylation of viral glycoproteins, exhibited the same distribution of envelope proteins as control cells, after infection with VSF or influenza. A temperature-sensitive mutant of influenza WSN, ts3, which, when grown at the nonpermissive temperature of 39.5 degrees C, retains the sialic acid residues in the envelope glycoproteins, showed, at both 32 degrees C (permissive temperature) and 39.5 degrees C, budding polarity and viral glycoprotein distribution identical to those of the parental WSN strain, when grown in MDCK cells. These results demonstrate that carbohydrate moieties are not components of the addressing signals that determine the polarized distribution of viral envelope proteins, and possibly of the intrinsic cellular plasma membrane proteins, in the surface of epithelial cells.

Animals↗
PubMed1979

The statistical treatment of correlated bilateral traits in the analysis of cranial material.

At present there is no standardized method to derive frequencies from bilateral non-metric traits. In this paper the commonly used methods are evaluated in light of statistical considerations and degree of sample preservation. In particular, we explore the question of dependence between sides for the bilateral traits. Several workers have tested for bilateral trait correlation in incorrect ways, confusing tests for differences in side frequencies with tests for independence. An easy method to test for independence, using the chi-squared test, is recommended. This test is used on 16 bilateral traits in a large sample of prehistoric carnia from Central California and significant dependence is found for all 16 of these traits. We suggest the traditional method of deriving frequencies be used. Both sides of the cranium should be considered, dividing the number of times the trait occurs by the number of sides available for observation. This method can be used even in poorly preserved samples. Side to side correlation may be compensated for by modifying the constants subtracted in the mean measure of divergence and in the expression for the approximate variance of the mean measure of divergence when the samples are drawn from identical populations.

California↗
PubMed1979

Analysis of dorsal pitting in the os publis in an extensive sample of modern American females.

Pubic bones from 486 modern American females between the ages of 13 and 99 were studied in an attempt to explore the relationship between the degree of dorsal pitting and the following variables: (1) number of full term pregnancies, (2) inteval since last pregnancy, (3) age of decedent.A statistical association was found between the number of full term pregnancies and the degree of dorsal pitting. However, the correlation is not strong; 17 females reported as being nulliparous have "medium to large" dorsal changes whereas 22 females having from one to five full term pregnancies have an absence of dorsal changes. Females who had their last child 15 or more years prior to death are more apt to have "medium to large" dorsal changes than are females who have more recently given birth. This effect appears to be independent of the number of full term pregnancies, but is probably related to age. When the data are analyzed by multiple regression analaysis, it is found that age and number of pregnancies are most important in predicting the degree of pitting and the effect of the interval on pitting is not significant. Age is found to be an important variable independent of the number of full term pregnancies. In nulliparas, an absence of dorsal pitting is far more frequently found in females younger than 30 than in those over 30.

Adolescent↗
PubMed1976

Partial purification and characterization of a heat-labile enterotoxin of Escherichia coli.

A partially purified enterotoxin was obtained from the growth medium of Escherichia coli strain 711 (P307), a derivative of E. coli K-12, by ultrafiltration, precipitation with ammonium sulfate, molecular sieving, and anion exchange column chromatography. The active moiety, which is heat-labile, behaved like a protein particle of 180,000 to 200,000 daltons during molecular sieving and ultracentrifugation. During polyacrylamide gel electrophoresis in sodium dodecyl sulfate (SDS-PAGE), it dissociated into two subunits with apparent molecular weights of 68,000 to 70,000 and 14,000 to 15,000. SDS-PAGE after heating in SDS changed the larger subunit to an apparent molecular weight of about 40,000; the smaller subunit did not change. The intact particle induced rounding of the cells in Y-1 mouse adrenal tumor cells used for assay. The detergent-dissociated molecules were not active. Proteolysis of the purified toxin by tolylsulfonyl phenylalanyl chloromethyl ketone-trypsin appeared to enhance its activity. The addition of serum to the assay medium resulted in partial depression of the activity. Activity was also abolished by preincubation of the toxin with either a rabbit antiserum to it or solutions containing GM1 ganglioside. The length of time needed to evoke a response in the assay system by fractions from different stages in the purification of the enterotoxin was a useful parameter in the evaluation of specific activity.

Bacterial Proteins↗