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Biomedical subjects

D Spencer

Publications and source records attributed to D Spencer.

At least 55 records · Page 3Linked to original sources

Physician reactions to the health care revolution. A grief model approach.

The American health care reform revolution has brought about major changes in the practice of medicine. As integral components of the health care system, physicians have felt the full impact of most of these changes. Change often involves losses for those affected, and, in this case, physicians are no exception. Many physicians have experienced losses of financial security, social status, independent clinical decision making and resource utilization, the practice option of independent private practice, hospital governance power, freedom of choice in specialty selection and geographic practice location, physician collegiality, continuity of patient relationships, and autonomy. We use Kübler-Ross' grieving model to help understand physician responses to their losses inherent in health care system reform. The grieving stages of denial, anger, bargaining, depression, and acceptance are applied to these physician responses and suggestions given to help physicians through this grieving process.

Anger↗

Accumulation of a sulphur-rich seed albumin from sunflower in the leaves of transgenic subterranean clover (Trifolium subterraneum L.).

A gene encoding a sulphur-rich, sunflower seed albumin (23% cysteine plus methionine) was modified to contain the promoter for the 35S RNA of cauliflower mosaic virus, in order to obtain leaf expression in transgenic plants. In addition, a sequence encoding an endoplasmic reticulum-retention signal was added to the 3' end of the coding region so as to stabilize the protein by diverting it away from the vacuole. The modified gene was introduced into subterranean clover (T. subterraneum L.) and its expression was detected by northern and western blots and by immunogold localization. The albumin was accumulated in the lumen of the endoplasmic reticulum, and, among six independent, transformed lines, it accumulated in the leaves of T0 transgenic plants at varying levels up to 0.3% of the total extractable protein. The level of accumulation of the sunflower albumin increased with increasing leaf age, and in the older leaves of the most highly expressing plants of the T1 generation it reached 1.3% of total extractable protein. Expression of the SSA gene was stable in the first and second generation progeny. These results indicate that there is potential for significantly improving the nutritional value of subterranean clover for ruminant animals such as sheep by expressing genes that code for sulphur-rich, rumen-stable proteins in leaves.

Albumins↗

Variations in the natural history and survival of patients with supratentorial low-grade astrocytomas.

Data from 55 consecutive patients with low-grade astrocytomas treated between 1982 and 1990 were analyzed to determine specific outcome factors, including time to recurrence, incidence of anaplastic transformation, and survival. Gender, type of symptoms, contrast enhancement, and timing of radiation therapy were not significant in determining outcome. Patients who had symptoms for > 2 years and underwent gross-total resection of the tumor, with age as a continuous variable, were associated with significantly longer time to recurrence and survival. Within the population of patients with low-grade astrocytomas, patients with chronic epilepsy clearly had the best prognoses. There were no tumor recurrences or deaths in 27 patients with chronic epilepsy, regardless of the extent of surgery and without the use of radiotherapy. Ten-year survival was 100% for 31 patients who underwent gross-total tumor resection, regardless of the length of preoperative symptoms. Immediate postoperative radiotherapy did not prolong the time to recurrence, reduce the incidence of transition to more malignant tumors at recurrence, or increase the length of survival when compared with delayed radiotherapy. Because recurrence with a high-grade lesion caused 92% of the mortality in our series, the benefit in patients who underwent aggressive surgery seems to result from a significant decrease in the risk of recurrence when compared with patients who underwent anything less than gross-total resection. Our data also suggest that variability in the natural history of low-grade astrocytomas has a strong influence in determining survival and that tumors associated with chronic epilepsy are much less likely to become more malignant over time.

Adult↗

Variants of Kaposi's sarcoma in Southern Africa. A retrospective analysis (1980-1992).

All types of Kaposi's sarcoma (KS) are represented in the Southern African region. We present a retrospective analysis of patients with KS, treated and followed up at the Johannesburg General Hospital over a 12-year period (1980-1992). One hundred and nineteen patients with KS, divided into four groups according to their etiology (classical; endemic African; renal transplant recipients; epidemic AIDS-related) were analyzed. Choice of treatment (radiotherapy or chemotherapy) was individualized and based on clinical criteria, extent of disease and severity of symptoms. Kaposi's sarcoma showed a very high response rate to radiation therapy, regardless of variant, radiation modality or schedule. Chemotherapy was also effective in the more aggressive pattern of endemic African KS. Epidemic Kaposi's sarcoma showed the same poor outcome as demonstrated by its Western counterpart. We conclude that radiation therapy can provide excellent palliation with only minimal side-effects in all variants of KS seen in Southern Africa.

Acquired Immunodeficiency Syndrome↗

Scleroderma and watermelon stomach.

Two patients with scleroderma (systemic sclerosis, SSc) and chronic blood loss secondary to gastric vascular ectasia--"watermelon stomach"--are presented. These cases exemplify the condition of gastric vascular ectasia and highlight the increasingly recognized association with autoimmune antibodies and connective tissue disease such as SSc. In both cases the onset of gastric blood loss coincided with the clinical manifestations of sclerodactyly by months, suggesting some temporal relationship. Although a number of different treatment modalities are available, and discussed in this report, both cases required gastrectomy.

Aged↗

Zinc reduces dentate granule cell hyperexcitability in epileptic humans.

The hippocampi of epileptic patients with medial temporal lobe epilepsy exhibit a characteristic pattern of anatomical changes including cell loss and sprouting of the granule cell axons, the mossy fibers, into the inner molecular layer of the dentate. In addition to glutamate, mossy fibers release Zn2+. In the present study we investigated the action of Zn2+ on excitatory synaptic potentials in the dentate granule cells of patients with medial temporal lobe epilepsy. We show here that Zn2+ limits the duration of excitatory responses in these cells, probably by blocking the N-methyl-D-aspartate (NMDA) receptors. Zinc may, therefore, play an important role in limiting epileptiform activity in this issue.

2-Amino-5-phosphonovalerate↗

Accumulation and proteolytic processing of vicilin deletion-mutant proteins in the leaf and seed of transgenic tobacco.

Vicilin, a 7S globulin of Pisum sativum L. seed, accumulates in protein-storage vacuoles (protein bodies) of cotyledonary storage-parenchyma cells. The synthesis and proteolytic processing of various genetically engineered proteins within the leaf and seed of a heterologous (tobacco, Nicotiana tabacum L.) host was examined. A modified vicilin gene, in which the DNA sequence corresponding to the signal peptide was removed, resulted in a polypeptide of 50 kDa in the tobacco leaf and seed; none of the normal proteolytic cleavage products characteristic of expression of an unmodified vicilin gene were obtained. Likewise, no vacuolar accumulation of this mutant vicilin occurred in leaf protoplasts, which is also supportive of the predicted cytosolic localization for this protein. In-frame deletions were made within the region of the vicilin gene encoding the mature protein, to eliminate the N-terminal 28 and 121 amino acids and the C-terminal 69 residues, while maintaining an intact signal peptide. All of these "mature" deletion-mutant proteins were accumulated to only low levels in the host, but exhibited the predicted molecular weight and underwent some normal proteolytic processing in the seed. Mutant vicilin proteins having deletions in either the N-terminus (delta NT 121) or C-terminus (delta CT 69) were not found in appreciable amounts within the vacuolar fraction of transgenic tobacco leaf protoplasts, perhaps due to protein degradation in this compartment. Compared with the intact vicilin, oligomer assembly of the C-terminal deletion-mutant protein was disrupted in leaf cells, which may have further affected protein stability.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗

Chemotherapy for AIDS-related and endemic African Kaposi's sarcoma in southern Africa.

BACKGROUND: Kaposi's sarcoma (KS), either in its endemic (African) form or its AIDS-related variant, is a common neoplastic disorder seen in Southern Africa. Chemotherapy has been proven to be very effective in advanced or relapsed African Kaposi's sarcoma, but much less so in AIDS-related, endemic KS. PATIENTS AND METHODS: The study consists of a retrospective analysis of the results of chemotherapy alone in 17 patients with African KS (AKS) and in 32 patients with epidemic AIDS-related KS (EKS), treated at the Johannesburg General Hospital between 1982 and 1992. Single agents included vinblastine, actinomycin D, bleomycin, and vincristine; combined regimens were largely doxorubicin/vincristine/bleomycin or etoposide/methotrexate. Outcome classifications were: complete remission (CR), partial remission (PR), and treatment failure (TF). RESULTS: Four of the 17 patients with AKS had CR, 10 a PR, and three were TF and died rapidly from their disease. The combined chemotherapeutic regimens produced marked symptomatic relief and even long-term remission in AKS. In patients with EKS, the response rate to chemotherapy was very low and of brief duration. No patient had a CR and debilitating side effects were common. CONCLUSIONS: The African type of AKS is a chemo-sensitive tumor, whereas the endemic type EKS, like its Western counterpart, has a dismal prognosis.

AIDS-Related Opportunistic Infections↗

Halsey needle holder for micro and mini slit grafting.

BACKGROUND: Few suggestions have been made to date concerning how to more reproducibly place scalp slits for micro- and minigrafts. OBJECTIVE: To improve on the unpredictable consistency of depth and angle of scalp slits for micro- and minigrafting. METHOD: Seven-inch Halsey needle holders were used to stabilize the cutting instruments (No-Kor microblades, #15c, and #15 blades) for making scalp slits for micro- and minigrafts on approximately 80 patients over 5 months. CONCLUSION: Using the Halsey needle holder or stabilization of the blades for slit placement of scalp micro- and minigrafting is superior to directly holding the blades by improving on depth, angle control, ease of holding and adjustment, and greater reproducibility.

Hair↗

Blood transfusion and its benefits in palliative care.

The value of blood transfusion as a supportive treatment in haematological disease and oncology is well established and is seen as an essential part of treatment. The place of blood transfusion in the alleviation of symptoms within palliative care units is less well established. There has been no evaluation of its benefits in terms of symptom relief and impact on the quality of life. This study was designed to identify the benefit achieved by transfusion as well as possible indicators for its appropriate use in the future. Ninety-seven patients were recruited over one year, from the beginning of September 1992 to the end of August 1993, from eight centres, all members of the South West Thames Palliative Medicine Collaborative Audit Group. Patients completed visual analogue scales before and on two occasions after transfusion, to assess its impact on dyspnoea, weakness and overall sense of well-being. Results indicated that a significant proportion showed improvement in all three parameters. Those whose main indication for transfusion was weakness showed a particular benefit. The group of patients entered into the study were anaemic in comparison with our normal patient population, but the degree of improvement seen did not correlate with the degree of anaemia prior to transfusion. We conclude that transfusion does offer symptom relief and improvement in well-being in patients with advanced malignant disease. It should be considered as a worthwhile option in palliative treatment of weakness, dyspnoea and impaired overall sense of well-being, when associated with anaemia.

Adolescent↗

Case report: pulmonary calcification after liver transplantation in children.

Pulmonary calcification following liver transplantation is a recognized phenomenon in adults but has not been previously described in children. We describe two children who developed pulmonary calcification after liver transplantation. Pulmonary calcification should be considered after liver transplantation when radiographic changes fail to resolve with appropriate treatment.

Calcinosis↗

Changes in plasma TGF beta levels during pulmonary radiotherapy as a predictor of the risk of developing radiation pneumonitis.

PURPOSE: To determine whether plasma transforming growth factor-beta (TGF-beta) levels measured before and during radical radiotherapy for lung cancer could be used to predict patients at risk for the development of radiation pneumonitis. METHODS AND MATERIALS: The first eight patients with lung cancer (nonsmall cell: seven, small cell: one) enrolled in a prospective study designed to evaluate physiological and molecular biologic correlates of radiation induced normal tissue injury are described. The study began in June 1991. All patients were treated with radiotherapy with curative intent. Plasma transforming growth factor-beta levels were obtained before, weekly during, and at each follow-up after treatment. Pretreatment pulmonary function tests and single photon emission computed tomography scans were obtained to assess baseline lung function and were repeated at follow-up visits. Dose-volume histogram analyses were performed to determine the volume of lung which received > or = 30 Gy. Patients were assessed at each follow-up visit for signs and symptoms of pneumonitis. RESULTS: Five patients developed signs and/or symptoms of pulmonary injury consistent with pneumonitis and three patients did not. In all three patients not developing pneumonitis, plasma TGF-beta levels normalized by the end of radiotherapy. In contrast, four out of five patients who suffered pneumonitis had persistently elevated plasma TGF-beta levels by the end of therapy. This finding appeared to be independent of the volume of irradiated lung. CONCLUSIONS: These results suggest that plasma TGF-beta levels during treatment may be useful to determine which patients are at high risk of developing symptomatic pneumonitis following thoracic radiotherapy. This finding may have implications when planning additional therapy (either chemotherapy or radiotherapy) which may have potentially adverse consequences on the lung.

Adult↗

Radiation therapy in epidemic, AIDS-related Kaposi's sarcoma in southern Africa.

AIMS AND BACKGROUND: Acquired Immunodeficiency Syndrome (AIDS) associated Kaposi's Sarcoma (EKS) is widely spread in the Southern African Region. No large studies concerning the role of radiation therapy in the Southern African variant of EKS have been reported to date. METHODS: Over a 10 year period (1982-1992) 25 patients with EKS (disseminated skin involvement) were treated primarily with radiation therapy at the Johannesburg General Hospital. Radiation fields were individually tailored to the extent of the disease. Total administered doses ranged between 8-12 Gy (single fraction) to 24-30 Gy fractionated over 2-3 weeks. RESULTS: Overall response and symptomatic relief rates were 72% and 80%, respectively. Toxicity was mild and manageable. CONCLUSIONS: Our retrospective analysis supports the use of radiation therapy for the Southern African type of EKS.

Acquired Immunodeficiency Syndrome↗

Radiation therapy in an elderly African population with Kaposi's sarcoma.

There are no published studies on the efficacy of modern radiation therapy in elderly populations with the endemic African type of Kaposi's sarcoma (AKS). The present retrospective analysis of 20 elderly AKS patients treated by radiotherapy attempts to supply information relevant to the older age group. It demonstrates that excellent symptomatic relief with minimal side effects can be attained and suggests that the role of radiotherapy as the treatment of choice in this particular group should be emphasized.

Africa↗