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Biomedical subjects

S L Roberts

Publications and source records attributed to S L Roberts.

At least 19 recordsLinked to original sources
PubMed2001

Survival of Escherichia coli O157:H7 and Salmonella on chill-stored vacuum or carbon dioxide packaged primal beef cuts.

The ability of two Escherichia coli O157:H7 strains (E27, a cattle isolate, and B6-914 gfp-91, a fluorescent marker strain) and two Salmonella serotypes (S. typhimurium and S. brandenberg) to survive on chilled preservatively packaged primal beef cuts was examined. Each of the strains was inoculated separately at two dilution levels (10(3) and 10(5) cfu g(-1)) onto 500 g beef steaks, packaged under vacuum or 100% carbon dioxide, and stored, with uninoculated controls, for 6 weeks at - 1.5 degrees C, then for 2 weeks at 4 degrees C. Bacterial numbers were determined by dilution and incubation at 37 degrees C for 24 h on either Sorbitol McConkey Agar or Xylose Lysine Desoxycholate Agar for E. coli O157:H7 and Salmonella samples, respectively. Counts were corrected for background growth and their accuracy checked using immunological tests. Fluorescent E. coli O157:H7 B6-914 gfp-91 was also counted under ultra-violet light. No significant changes in numbers of the E. coli O157:H7 or Salmonella strains occurred during storage at either - 1.5 or 4 degrees C packaged under either vacuum or carbon dioxide. The ability of these pathogens to survive standard preservative packaging conditions is different from that reported from their generic counterparts and therefore a cause for public health concern.

Animals↗
PubMed1999

Effects of ovarian hormones and environment on radial maze and water maze performance of female rats.

The effects of gonadal hormones and environment on performance in an eight-arm radial maze and in the Morris water maze were determined in female rats. Long-Evans female rats were ovariectomized or sham ovariectomized at 35 days of age, and housed in complex environments or in isolation for the duration of the study. One month following surgeries, spatial working memory performance in the radial maze was assessed. Exposure to complex environmental conditions independently enhanced performance, as indicated by increased arm choice accuracy during 20 days of maze training. Additionally, gonadally intact females significantly outperformed ovariectomized females before cyclicity was disrupted by food deprivation. Following radial maze training, spatial reference memory performance was assessed in the same females utilizing the Morris water maze. Gonadally intact females housed in isolation performed significantly more poorly during 16 days of place training trials and displayed significantly shorter times in the platform quadrants and fewer target crossings during probe trials than gonadally intact and ovariectomized females housed in complex environments and ovariectomized rats housed in isolation. Consequently, acquisition and retention of the water maze was impaired by the presence of ovaries, and this impairment was counteracted by exposure to complex environments. Performance did not differ between groups on cued trials, indicating that sensorimotor and motivational functions did not differ between groups. Results of these experiments indicate that endogenous gonadal hormones can differentially affect performance on tasks of spatial working and spatial reference memory, and that environmental conditions can interact with gonadal hormones to affect behavior.

Animals↗
PubMed1997

Oral and maxillofacial surgery. A specialty altered by time and circumstance.

The evolution of oral and maxillofacial surgery into a specialty was aided by international strife in the first half of the century. Today the scope of OMS practice continues to expand as the result of an educational process that is responsive to the changing needs of the specialty. But understanding and acceptance of the OMS scope of practice lags behind.

Bone Transplantation↗
PubMed1996

DNA sequence analysis of the C4 antigen WH: evidence for two mechanisms of expression.

Amino acid and protein analyses have allowed the construction of a model for the C4-based Rodgers and Chido blood group antigens. The single low-frequency allele (WH) in this blood group system, however, has not been characterized at the molecular level. Two WH+ donors were studied by C4 agarose gel electrophoreses, immunoblot studies using monoclonal anti-Rg: 1 or anti-Ch: 1, serological phenotyping, polymerase chain reaction-restriction fragment length polymorphism of their C4 genes, and DNA sequencing of the WH allele. The first donor had the C4A1, A3 phenotype; the C4A1 carried Ch: 1, 3, 6 (thus exhibiting reversed antigenicity) and the C4A3 carried the WH antigen. The amino acid sequence of the WH allele was PCPVLD at positions 1101 - 1106, S at position 1157, and VDLL at positions 1188 - 1191. A second donor typed as C4A2, A4, B1 and was also WH+. Immunoblot analysis showed that a C4B1 protein expressed Rg: 1. Sequence analysis of the C4B genes showed the amino acids LSPVIH at positions 1101 - 1106, S at position 1157, and ADLR at positions 1188 - 1191. Thus, the WH antigen is a conformational epitope that can arise through different mechanisms on either a C4A or C4B gene.

Alleles↗
PubMed1996

A cognitive model for assessing depression and providing nursing interventions in cardiac intensive care.

Depression is an emotion experienced by each individual as some point in his or her lifetime. For some, the feelings are temporary, such as when one feels momentarily let down. For others, the feelings are deeper and may last for longer periods of time. Deeper and longer lasting depression may occur when individuals are confronted by certain unfavourable types of life situations such as a major physiological loss. For a once healthy individual, the depression associated with a physiological loss has penetrated through the individual's prior coping process and defences. Depression is a particularly common problem in individuals with a medical illness (Cavanaugh 1983). Heart disease is often experienced as a major loss for patients. Reports of depression in patients with coronary artery disease have ranged from 18% to 60% (Clark 1990). A broad range of physical disorders are commonly associated with depression. Among the most prominent disorders is congestive heart failure (Buckwater & Babich 1990). For depressed congestive heart failure (CHF) patients, a critical care nurse needs to assess the factors contributing to depression and recognise behaviours reflective of depression to be able to make appropriate nursing diagnoses and devise a plan to manage the patient's depression. To help critical care nurses accomplish this goal, this article contains an examination of depression as it applies to CHF patients according to Beck's cognitive triad (Ulerman et al 1984).

Cognition↗
PubMed1996

Hope facilitating strategies for the family of the head injury patient.

Approximately 200 new head injuries are reported per 100,000 population each year in the United States. These injuries are more common in younger men and caused most frequently by motor vehicle accidents. Head injuries occur suddenly and unexpectedly. Head injury affects not only the individual but the family as well. The family's functional abilities are threatened by the head injury of a family member. The family's adaptation to head injury and life-threatening events surrounding the injury has a significant impact on the patient's rehabilitation. A family's response of denial or lack of hope in the future has been identified as a major obstacle to successful adaptation. The hopeless family may be unable to make necessary changes at home or learn important aspects of the patient's care. Depending upon the extent of the head injury, the family needs to know that most head trauma patients make significant progress in the first six months. Progress usually continues, less dramatically, for the next two to three years.

Accidents, Traffic↗
PubMed1996

Hopelessness in the myocardial infarction patient.

Events that cause hopelessness following a myocardial infarction may include coronary heart disease, reality-based misperceptions, lack of future goals and lack of relatedness to others. The susceptibility to hopelessness will depend on how successful the patient has been in accepting previous cardiac-related problems. Once hopelessness occurs, the patient may perceive the future to be limited. Hopelessness centers around seven components: physiological, cognitive, temporal, affective, behavioral, affiliative and contextual loss of hope. This article outlines how hopeless patients may distort their immediate environment and future goals. Methods of identifying hopelessness and intervening with appropriate nursing interventions, which will assist with the management of hopelessness, are described.

Adult↗
PubMed1995

Acute congestive heart failure: pathophysiological alterations.

The goal of a healthy heart is to transfer blood coming to the ventricles from the low pressure venous system into the high pressure arterial system. In acute congestive heart failure (CHF), impaired cardiac function leads to failure to empty venous reservoirs and therefore to reduce delivery of blood into the arterial circulation (Michaelson 1983). Once heart failure occurs it has a high mortality rate. According to the Framingham Heart Study, 50% of patients with New York Heart Association class II or III heart failure died within 5 years. With class IV patients, 50% survived less than 1 year (Cupples 1987). The purpose of this article is first to define acute CHF. Secondly, the pathophysiological alterations that occur as a result of strained and misdirected compensatory mechanisms will be discussed to help critical care nurses to recognise why certain patients are at risk of developing acute CHF.

Acute Disease↗
PubMed1995

Nursing management of congestive heart failure. Part I.

Congestive heart failure (CHF) is a common clinical problem and in its advanced stage has a poor prognosis. Approximately 400,000 individuals develop heart failure each year (Parmley 1989). CHF can be caused by coronary artery disease such as myocardial infarction, ischemia and hypertension. Should heart failure occur as a result of acute myocardial infarction, a classification tool developed by Killip can be used to assess the degree of CHF. Killip's classification is organised into the following four categories: Class I: no heart failure Class II: mild to moderate failure Class III: acute pulmonary oedema Class IV: cardiogenic shock (Killip, as cited by Benz 1989). This system helps in organising clinical signs and symptoms of heart failure. Due to the fact that CHF is now the most common hospital discharge diagnosis for those over the age of 65, critical care nurses need to be able to recognise complications and intervene rapidly (Parmley 1989) in collaboration with medical staff. The purpose of this paper is first to discuss cardinal signs and symptoms and clinical data associated with CHF. Second, critical care nurses' management of CHF is organised around common nursing diagnoses.

Cardiovascular Agents↗
PubMed1995

Circle of Willis: evaluation with spiral CT angiography, MR angiography, and conventional angiography.

PURPOSE: To evaluate the use of spiral computed tomographic (CT) angiography in the analysis of the arteries of the circle of Willis and compare these results with magnetic resonance (MR) angiography and conventional angiography. MATERIALS AND METHODS: The results in 17 patients who underwent examination were prospectively studied in a blinded fashion. The presence or absence of the arteries of the circle of Willis was determined by using maximum intensity projection reconstructions from CT angiography and MR angiography. These results were compared with results from conventional angiography. RESULTS: Similar sensitivities were determined for CT angiography (88.5%) and MR angiography (85.5%); however, MR angiography was found to differ significantly (P = .005) from conventional angiography. No significant differences (P > .05) were found between the two modalities and conventional angiography in the detection of the anterior, middle, or posterior cerebral arteries or the anterior communicating artery. CONCLUSION: Spiral CT angiography is highly sensitive in the detection of arterial anatomy in the circle of Willis and is a reliable alternative to MR angiography.

Cerebral Angiography↗
PubMed1993

Ciliary neurotrophic factor maintains motoneurons and their target muscles in developing rats.

Ciliary neutrophic factor (CNTF) can enhance motoneuron survival during naturally occurring cell death in the chick (Oppenheim et al, 1991). Because receptors for CNTF are expressed in both motoneurons and their target muscles (Davis et al., 1991; lp et al., 1993), both tissues are potential sites of CNTF action in development. We examined the ability of CNTF to prevent the degeneration of a neuromuscular system in developing female rats. The death of motoneurons in the spinal nucleus of the bulbocavernosus (SNB) extends postnatally and is sexually dimorphic, with many more motoneurons dying in females than in males. The bulbocavernosus (BC), a target muscle of SNB motoneurons, also degenerates postnatally in females. Female rats treated with daily injections of 1 microgram CNTF from embryonic day 22 through postnatal day 3 (P3) had 70% more SNB motoneurons on P4 than did control animals, and the number of pyknotic profiles in the SNB area was markedly reduced by CNTF. In addition, the degeneration of the BC was completely prevented by CNTF treatment of perinatal female rats. These results demonstrate that CNTF can preserve mammalian motoneurons from developmental death, but also suggest that the sparing effect of CNTF on motoneurons in vivo may be a secondary consequence of effects on target muscles.

Analysis of Variance↗
PubMed1992

Regulation of motoneuron death in the spinal nucleus of the bulbocavernosus.

A sexual dimorphism in the number of motoneurons in the spinal nucleus of the bulbocavernosus (SNB) of rats is engendered by a sex difference in ontogenetic cell death. Testicular secretions, specifically androgenic steroids, reduce SNB motoneuron death in males. The fate of the target muscles generally mirrors that of the motoneurons, and androgens appear to exert their effects upon the target muscles, sparing the motoneurons as a secondary consequence. Treatment with ciliary neurotrophic factor can also spare SNB motoneurons in newborn females, raising the possibility that this factor normally mediates androgen's effect upon motoneuron survival. The ontogeny of calcitonin gene-related peptide immunoreactivity is delayed in SNB cells compared with other motoneurons and is further delayed in the SNB cells of females. In both sexes, calcitonin gene-related peptide is detected after the period of SNB motoneuron death is complete. A sex difference in motoneuron number is also seen in the human homologue of the SNB and, because ontogenetic death of motoneurons in humans overlaps the period of androgen secretion, may arise in a manner similar to that in the rat SNB.

Animals↗
PubMed1991

Preoperative radiation therapy followed by extrafascial hysterectomy in patients with stage II endometrial carcinoma.

Seventy-four patients with Stage II endometrial cancer were treated by a combination of preoperative radiation therapy followed by extrafascial hysterectomy, bilateral salpingo-oophorectomy, and paraaortic lymph node sampling at the University of Kentucky Medical Center from 1967 to 1988. All patients had histologically confirmed endometrial cancer with involvement of the endocervix. The cell types and numbers of the tumors treated were as follows: adenocarcinoma, 58; adenoacanthoma, six; adenosquamous carcinoma, nine; and clear cell carcinoma, one. Preoperative radiation consisted of 4500 cGy external therapy followed by one intracavitary implant providing an additional 2000 cGy to point A. Surgery was done 4 to 6 weeks after completion of radiation therapy. Five patients (7.1%) had paraaortic lymph node metastases. Four were treated with extended-field radiation therapy and one with platinum-based combination chemotherapy. After treatment, the patients were followed at regular intervals from 2 to 22 years (mean, 5.4 years). Eleven patients (15%) had recurrent cancer, with the vagina and upper abdomen being the most common sites of spread. The estimated 5-year and 10-year disease-free survival rates of these patients are 88% and 76%, respectively. Cell type, depth of myometrial invasion, and lymph node status were the most important prognostic variables in the patients evaluated. These data confirm that the combination of preoperative radiation therapy and surgery produces excellent long-term survival in patients with Stage II endometrial cancer.

Adenocarcinoma↗