PubMed Health⌕ Search

Biomedical subjects

S K Mitchell

Publications and source records attributed to S K Mitchell.

14 recordsLinked to original sources
PubMed1999

Unusual metastatic behavior and clinicopathologic findings in eight cats with cutaneous or visceral hemangiosarcoma.

Eight cats with visceral or cutaneous hemangiosarcoma were evaluated, and unusual metastatic and clinicopathologic behavior was evident in each. Cutaneous hemangiosarcoma is generally believed to be locally aggressive and slow to metastasize. These 8 cats with cutaneous hemangiosarcoma, however, developed metastatic disease after initial surgical resection; only 1 had local regrowth of the tumor. All cats with visceral hemangiosarcoma had metastasis at the time of diagnosis, which is consistent with cats of other reports. Three of 8 cats had evidence of disseminated intravascular coagulation, including increased prothrombin time and partial thromboplastin time, decreased number of platelets, and anemia. These potential complications need to be considered when planning diagnostic and treatment protocols.

Abdominal Neoplasms↗
PubMed1999

The eye and orbit.

Computed tomography (CT) and magnetic resonance imaging (MRI) provide excellent morphological detail of the eye and its associated structures. In veterinary medicine, these imaging modalities are most often used to diagnose and determine the extent of ocular or periocular tumors. They may also be used to diagnose inflammatory conditions of the orbital region and to determine the severity and extent of ocular trauma. This article reviews the applications of CT and MRI for ocular and orbital diseases, discusses normal findings, and presents representative case examples.

Animals↗
PubMed1997

Chemoprophylaxis with ciprofloxacin in ovarian cancer patients receiving paclitaxel: a randomized trial.

The objective of this study was to evaluate the efficacy of oral ciprofloxacin in preventing febrile morbidity superimposed on the neutropenia induced from a paclitaxel regimen in ovarian cancer patients. Eligible patients received paclitaxel at doses of 135 to 175 mg/m2 alone or in combination with a platinum agent. They were randomized to either an observation (control) group or a ciprofloxacin prophylaxis group. Patients in the ciprofloxacin group received 500 mg ciprofloxacin orally twice a day once the absolute neutrophil count (ANC) was less than 500/mm3 and continued until the ANC was greater than 1000/mm3. Ninety patients were enrolled between the control (n = 45) and ciprofloxacin (n = 45) groups. They received 371 cycles of a paclitaxel-based regimen with 177 and 194 cycles in the control and ciprofloxacin groups, respectively. Ciprofloxacin prophylaxis was prescribed for 138 (71%) of the cycles in the ciprofloxacin group and was given for a mean duration of 7.7 days per cycle. The groups were similar in disease status and risk factors for neutropenia. Fifteen patients in the control group developed febrile neutropenia versus 12 of those in the ciprofloxacin group (P = 0.69). The mean ANC and mean length of hospital stay for neutropenic fever were also similar between groups. There was a greater frequency of an ANC < 100 associated with those prophylaxed with ciprofloxacin (P = 0.01). Only 44% of the febrile episodes were associated with a positive culture. Staphylococcus aureus was the most frequently reported organism isolated. Considering these results, it does not appear that febrile neutropenia is reduced by ciprofloxacin during grade IV neutropenia.

Administration, Oral↗
PubMed1994

Chemoprophylaxis with oral ciprofloxacin in ovarian cancer patients receiving taxol.

The purpose of this study was to review the clinical outcomes and cost of administration of a prophylactic antibiotic compared to G-CSF for the prevention of neutropenic morbidity associated with taxol. The study group was composed of 62 patients with ovarian cancer who received a 24-h infusion of a taxol-based regimen at doses less than or equal to 175 mg/m2 between June 1992 and April 1994. The records were retrospectively reviewed and the patients were grouped and analyzed according to the management of their myelosuppression. Group I patients (n = 29) were observed until their absolute neutrophil count (ANC) was less than 500/microliters and then were placed on ciprofloxacin 500 mg orally twice a day until their ANC was 1,000/microliters. Group II patients (n = 15) received G-CSF from Day 2 until the ANC was greater than 10,000/microliters beginning with their first cycle. Group III patients (n = 18) received their taxol regimen without either ciprofloxacin or G-CSF. Two hundred eighty-two taxol-based chemotherapy cycles were administered to these 62 patients. There was no statistically significant difference between the groups concerning disease status as measured by age, stage, performance status, dose intensity, or number of previous regimens. There were two episodes of febrile neutropenia in Group I and three episodes in Group II. Group III had 15 episodes of febrile neutropenia. The estimated cost of the different prophylactic regimens was $5,215.00 for Group I versus $104,000.00 for G-CSF in Group II. Within the three groups, there were 27 patients with an episode of febrile neutropenia (n = 20) or prolonged myelosuppression (n = 7) that were followed for an additional 104 taxol cycles. Twenty-four of these patients received G-CSF prophylaxis with intermittent ciprofloxacin and three received only ciprofloxacin. There were eight more episodes of febrile neutropenia in the patients receiving G-CSF. There were no additional febrile episodes on cycles prophylaxed with ciprofloxacin. There was no septic mortality. For patients receiving a 24 h infusion of taxol at doses less than 175 mg/m2, ciprofloxacin given through the ANC nadir may be effective in preventing febrile morbidity. A prospective randomized trial is underway to evaluate this approach.

Administration, Oral↗
PubMed1993

Temporal control on interval schedules: what determines the postreinforcement pause?

On fixed-interval or response-initiated delay schedules of reinforcement, the average pause following food presentation is proportional to the interfood interval. Moreover, when a number of intervals of different durations occur in a programmed cyclic series, postreinforcement pauses track the changes in interval value. What controls the duration of postreinforcement pauses under these conditions? Staddon, Wynne, and Higa (1991), in their linear waiting model, propose control by the preceding interfood interval. Another possibility is that delay to reinforcement, signaled by a key peck and/or stimulus change, determines the subsequent pause. The experiments reported here examined the role of these two possible time markers by studying the performance of pigeons under a chained cyclic fixed-interval procedure. The data support the linear waiting model, but suggest that more than the immediately preceding interfood interval plays a role in temporal control.

Animals↗
PubMed1990

Convergent inputs to the inferior olive from the dorsal column nuclei and pretectum in the cat.

The dorsal column nuclei (DCN) consist of an anatomically heterogeneous population of neurons, some of which project to the inferior olive and pretectum. Recent anatomical experiments on cats have shown that neurons in the parts of the pretectum which receive input from DCN also project to the inferior olive. Thus, DCN neurons provide an input to the inferior olive via both a direct DCN-olivary pathway and an indirect pathway through the pretectum. This connective situation provides a mechanism by which incoming somatic sensory information that is processed at different levels of the brainstem (i.e. DCN and pretectum) has access to the cerebellum by way of the inferior olive. It is of interest whether the two sets of differently processed information are conveyed to the same group of inferior olive neurons. Although DCN and pretectal projections to the inferior olive have been generally described, the relationship between the DCN targets in the inferior olive and those specifically from the DCN-recipient parts of the pretectum have not. To address this question, this study used single and double anterograde labeling strategies with a variety of tracers to compare the two targets in the inferior olive of cats. It was found that projections to the inferior olive from the DCN-recipient parts of the pretectum were located predominantly in the dorsal accessory portion of the inferior olive where they overlapped extensively with projections directly from DCN. These results provide evidence for a pathway by which sequentially processed somatic sensory information, first in the DCN and then in the pretectum, has access to the cerebellum by way of the same group of inferior olive neurons.

Animals↗
PubMed1988

Prevention of parenting alterations for women with low social support.

Parenting is a demanding role. Traditionally societies provide mechanisms for supporting major caregivers. For most parents the partner relationship is a source of refueling energy. In addition, often the extended family members provide support for the parent(s). In a prior research study dealing with early intervention where the family demonstrated double vulnerability, defined by pregnancy complications and social problems, we found the mothers most resistant to help were women who both had a lot of situational problems and few if any friends or family supporting them (Barnard et al. 1985). This finding prompted us to think about parents who did not have the supportive mechanisms cultures generally provide.

Affective Symptoms↗
PubMed1986

Cerebral vasospasm: theoretical causes, medical management, and nursing implications.

Cerebral vasospasm is a potentially life-threatening complication following subarachnoid hemorrhage (SAH) from a ruptured cerebral artery aneurysm. Traditionally, vasospasm has been treated with a variety of medical interventions. However, surgical intervention with an extracranial to intracranial (EC/IC) bypass graft has yielded promising results in a limited group of patients. This article discusses the theoretical causes of cerebral vasospasm, its clinical presentation, diagnosis, and treatment modalities. Nursing interventions for the patient experiencing cerebral vasospasm are also presented.

Blood Pressure↗
PubMed1985

Extracranial-intracranial bypass surgery.

Although the indications and effectiveness of the operation remain controversial, extracranial-intracranial (EC-IC) bypass surgery has become a common method in the treatment of patients with cerebral vascular disease. The technical feasibility of the procedure and its low mortality and morbidity rates are well established. However, its usefulness remains unproven in a variety of clinical, angiographic and regional cerebral blood flow patterns. This discussion focuses on the purpose of EC-IC bypass surgery as well as the procedure itself and postoperative nursing care.

Aged↗
PubMedDate not supplied

Efficacy and tolerability of lower-dose topotecan in recurrent ovarian cancer: a retrospective case review.

Topotecan (1.5 mg/m(2)/day for 5 consecutive days of a 21-day cycle) is an established recurrent ovarian cancer treatment, but myelosuppression can be dose limiting. This study evaluates the activity and tolerability of low-dose topotecan in our clinical experience. Case records were reviewed for patients with recurrent ovarian cancer in first through third relapse. Eligible patients had received > or =2 cycles of < or =1.25 mg/m(2) topotecan. Adverse events were evaluated using laboratory and clinical evaluation data. Twenty-seven eligible patients, most with advanced disease, received a total of 209 cycles (median, six cycles). Grade 3 or 4 hematologic toxicities during 184 cycles in 24 assessed patients were neutropenia, leukopenia, thrombocytopenia, and anemia in 35%, 28%, 36%, and 11% of cycles, and 21, 19, 16, and 10 patients, respectively. Only four grade 4 toxicities occurred: anemia (one) and thrombocytopenia (three). Myelosuppression was reversible, noncumulative, and manageable. Moreover, nonhematologic toxicity was generally mild to moderate, and the only two grade 3 events were constipation and deep vein thrombosis. Low-dose topotecan was active in this setting. Lower-dose topotecan is generally well tolerated and active in patients with pretreated ovarian cancer. Prospective clinical trials of low-dose topotecan in recurrent ovarian cancer are warranted.

Adult↗
PubMedDate not supplied

Rubin's "Puerperal Change" reconsidered.

A preliminary study was conducted to examine if healthy new mothers exhibit Rubin's "Taking-in" and "Taking-hold" behaviors and attitudes and if these behaviors and attitudes change during the course of hospitalization. Twenty subjects were surveyed on each postpartal hospital day at a large, west coast urban hospital. While the women exhibited some of the behavior and attitude changes, the findings do not support the specific time aspects described by Rubin. Implications for nursing practice, education, and research are discussed.

Attitude↗
PubMedDate not supplied

Evaluation of renal hemodynamics in awake and isoflurane-anesthetized cats with pulsed-wave Doppler and quantitative renal scintigraphy.

The feasibility and reproducibility of obtaining the pulsed-wave Doppler measurements of resistive index (RI) and pulsatility index (PI) were investigated in intrarenal arteries of normal, nonsedated cats, and cats anesthetized with isoflurane. In addition, relative renal function and relative renal blood flow were evaluated using quantitative renal scintigraphy. The percentage of injected dose uptake, time to peak activity, and two indices of renal blood flow (K/A ratio and flow index) obtained during the first pass of 99mTc-MAG3, were determined for both awake and anesthetized cats. Results indicate that measuring RI and PI in nonsedated cats is readily accomplished and that the results are reproducible within an animal. Mean RI and PI values in the awake cats were 0.55 and 0.8, respectively. Significant differences between the awake and anesthetized cats were found for all pulsed-wave Doppler and quantitative renal scintigraphic measurements evaluated.

Anesthesia, Inhalation↗
PubMedDate not supplied

Renal nuclear medicine: a review.

Renal nuclear medicine is used to evaluate renal function and morphology. Renal scintigraphy is the best imaging modality for evaluation of functional parameters such as glomerular filtration rate and effective renal plasma flow. The commonly used renal radiopharmaceuticals are reviewed. Both imaging and non-imaging techniques are presented. Specific applications of renal nuclear medicine are discussed.

Animals↗