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Biomedical subjects

A Davis

Publications and source records attributed to A Davis.

At least 37 records · Page 2Linked to original sources
PubMed1996

Evaluation of blood pressure response to the combination of enalapril (single dose) and diltiazem ER (four different doses) in systemic hypertension.

Angiotensin-converting enzyme inhibitors and calcium antagonists are 2 classes of antihypertensive agents frequently used either as monotherapy or in combination. A 6-week, multicenter, randomized, double-blind, placebo-controlled trial was conducted in essential hypertensive patients (diastolic blood pressures [BP] when seated, 95-115 mm Hg) to evaluate the efficacy, dose response, and safety profiles of enalapril combined with a new once-daily formulation of diltiazem. BP and heart rate were measured at 5 (peak) and 24 (trough) hours after dose to assess the efficacy and pharmacodynamic profile of the combination given once daily. There were 336 patients randomly assigned to either enalapril 5 mg plus 1 of 4 dose levels of diltiazem ER (60, 120, 180, or 240 mg), enalapril 5 mg alone, or placebo. Each combination dose level produced statistically significant reductions (p <0.05) in trough diastolic BP when seated, compared with placebo (-6.8, -8.3, -10.1, and -10.3 mm Hg for the diltiazem ER doses of 60, 120, 180, and 240 mg, respectively). The 3 highest combination dose levels resulted in statistically significant (p <0.05) decreases in trough diastolic BP when seated, compared with placebo. There was a significant (p <0.001) linear dose-response relation. A trough-to-peak ratio > or = 0.5 was shown for the 3 highest combination doses. Drug-related adverse events were seen in 8.9% to 19% of the combination patients, 14.3% of the enalapril patients, and 8.6% of the placebo patients. The frequency and type of adverse events were those currently noted with each drug studied when used as monotherapy.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1996

Elevated protein kinase CK2 activity in chromatin of head and neck tumors: association with malignant transformation.

We hypothesized that malignant transformation of normal mucosa of the upper aerodigestive tract to squamous cell carcinoma of the head and neck (SCCHN) might be associated with altered CK2 activity in the chromatin compartment of these tumors. We measured CK2 activity in the cytosol and chromatin of 7 surgical specimens of SCCHN, and 5 specimens of normal oropharyngeal mucosa from non-smokers/non-drinkers. CK2 activity in SCCHN tumors was significantly elevated in both the nuclear chromatin (P < 0.0005) and cytosolic (P <0.04) compartments relative to normal mucosa. These data suggest that activation of dysregulation of the chromatin-associated CK2 signal may play a role in the pathobiology od SCCHN.

Amino Acid Sequence↗
PubMed1996

Soft tissue sarcoma of the extremity. Limb salvage after failure of combined conservative therapy.

PURPOSE: To assess the results of salvage therapy using surgery alone or surgery and re-irradiation for patients with locally recurrent extremity soft tissue sarcoma (STS) following conservative surgery and radiotherapy. MATERIALS AND METHODS: 25 patients with locally recurrent STS after conservative surgery and irradiation were assessed between 1990 and 1995. Two patients with concurrent systemic relapse were treated palliatively. Seven patients were not candidates for conservative re-excision and underwent amputation, 11 patients underwent conservative resection without irradiation. Seven of these patients relapsed, and five went on to receive combined conservative surgery and re-irradiation. A further five patients initially received combined retreatment, for a total of ten patients treated with combined conservative surgery and re-irradiation. Six of these ten patients were treated with brachytherapy alone, one with brachytherapy and external beam therapy, and three with external beam therapy alone. The median retreatment dose was 49.5 Gy (range 35-65 Gy), and the median cumulative soft tissue dose was 100 Gy (range 93-120 Gy). RESULTS: The median follow-up from the most recent treatment is 24 months (range 7-42 months). At the last follow-up 14 patients are alive and disease free; two are alive with local disease and four with systemic disease, and five are dead of disease. Overall local control is 19/23 (91%). The local control for patients treated with conservative excision without irradiation is 4/11 (36%) and for conservative excision with re-irradiation 10/10 (100%). Six (60%) of these patients experienced significant post-irradiation would-healing complications, but three have recovered fully. Functional scores for the entire treated group are significantly lower after treatment, as are those for patients undergoing combined surgery and re-irradiation, but 70% of those treated with conservative surgery and re-irradiation and a good or excellent post-treatment functional score. CONCLUSIONS: Combined conservative surgery and re-irradiation provided superior local control to local re-excision alone and a functional outcome superior to amputation. Combined treatment with re-irradiation should be considered the primary salvage therapy for patients who fail combined therapy and who are suitable for conservative re-excision. Systemic relapse is a significant problem, and optimal therapy should minimize the risk of local relapse after the initial therapy. Eighteen patients (72%) had a history of intralesional excision as their initial intervention, and suggests that inappropriate initial management is a risk factor for relapse after combined conservative therapy. Improvements in therapy must include the appropriate education of the primary care physicians.

Adult↗
PubMed1996

Familial paraganglioma.

Non-secreting paragangliomas are rare tumours usually present in the head and neck. We describe an unusual case of familial paraganglioma with cranial nerve palsies. After exhaustive investigation, a vagal paraganglioma, was found and excised. The positive family history of paraganglioma was of significance, although this was only present in one of five generations. The diagnosis and management of non-secreting paragangliomas is discussed.

Cranial Nerve Neoplasms↗
PubMed1996

Residual disease following unplanned excision of soft-tissue sarcoma of an extremity.

Sixty-five patients who had been referred to our unit for additional management after an unplanned excision of a soft-tissue sarcoma of an extremity at another institution were studied retrospectively to determine the prevalence of residual tumor and to identify factors that predict which patients will have a tumor following such an excision. Unplanned excision was defined as excisional biopsy or unplanned resection of the lesion without benefit of preoperative imaging and without regard for the necessity to resect the lesion with a margin of normal tissue. In each patient, histological evaluation of the specimen removed at the unplanned excision had demonstrated positive resection margins, but postoperative physical examination on our unit revealed no gross evidence of residual tumor and no tumor was identified on cross-sectional imaging of the local site. Patients who had evidence of residual disease on physical examination or on imaging were thought to have definite evidence of sarcoma at the site of the operative wound and were therefore excluded from the study. After multidisciplinary consultation, all patients had a repeat resection at our cancer center. Extensive pathological sampling of the specimen from this second procedure was carried out, with sections obtained at mean intervals of 1.2 +/- 0.7 centimeters. Nodules initially thought to indicate disease were identified grossly in twenty-seven (42 percent) of the sixty-five patients, but histological evaluation confirmed the presence of tumor in only sixteen (59 percent). Histological evidence of sarcoma was identified in seven additional patients in whom gross nodules were not apparent in the specimen. Thus, sarcoma was identified in a total of twenty-three (35 percent) of the sixty-five patients. The mean duration of follow-up was forty-six months (range, twenty-four to eighty months; median, thirty-nine months). The margins of the second resection were positive in nine (39 percent) of the twenty-three patients who had residual sarcoma. Five (22 percent) of the twenty-three had a local recurrence. Four of the five patients who had a local recurrence had positive margins on repeat resection. This rate of local recurrence (five of twenty-three patients) was significantly higher than that in the remainder of our patients who had a soft-tissue sarcoma of an extremity (sixteen [7 percent] of 227) (p = 0.03). There was no association between the detection of sarcoma at the second procedure and the initial size or grade of the tumor, the use of irradiation preoperatively, or the interval between the initial, unplanned excision and referral to our cancer center. These data indicate that it is not possible to predict which patients will have residual tumor at the site of the operative wound. Therefore, it is prudent to advise repeat excision for all patients who have had an unplanned excision of a soft-tissue sarcoma of an extremity. Unplanned excision complicates decision-making in the treatment of this disease and should be avoided.

Biopsy↗
PubMed1996

Varus osteotomy of the distal part of the femur. A survivorship analysis.

Varus osteotomy of the distal part of the femur is often the procedure of choice for the treatment of osteoarthrosis of the lateral compartment associated with genu valgum. We followed twenty-one knees (twenty patients) long term or until failure. At the most recent evaluation (average, 133 months; range, ninety-seven to 240 months), thirteen osteotomies were still successful, seven had failed, and one patient (in whom the knee had remained functional) had died. Of the seven failures, three occurred early (at twelve or twenty-four months) and four occurred late (between seventy-two and ninety-eight months). The probability of survival at ten years was 64 per cent (95 per cent confidence interval, 48 to 80 per cent), as determined with use of the Kaplan-Meier method. We concluded that, with proper selection of patients, this procedure is effective for the treatment of gonarthrosis of the lateral compartment associated with valgus deformity.

Adult↗
PubMed1996

Using audiotapes to monitor student-preceptor interactions in a decentralized clerkship.

BACKGROUND: Community-based preceptors are increasingly being used to provide clinical experiences for medical students; therefore, the issue of when and how to monitor the appropriateness of teacher-learner interactions in the clinical setting has become increasingly complex and urgent. This paper describes how an audiotaping program in a department of family medicine was designed to account for preceptor and student needs and what this audiotaping experience revealed about the teaching strengths and weaknesses of full-time and volunteer faculty. METHODS: Audiotaped case discussions between third-year students and preceptors were evaluated using a structured instrument that reflected important responsibilities of clerkship preceptors. Reviews were compared using chi-square to evaluate for significant differences between university and community preceptors in overall quality of interaction with students and in specific deficiency areas. Ninety-five percent confidence intervals were used to evaluate for significant differences in frequency of occurrence among deficiencies. RESULTS: A total of 376 audiotaped case discussions were reviewed between July 1992 and June 1994. University preceptors had significantly more "superior" interactions with students than their community peers (P < .05). However, university and community preceptors had nonsignificant differences when specific deficiency areas were compared. Deficiencies in students who were allowed to present cases and assessments occurred significantly less frequently, while deficiencies in preceptors using open-ended questions occurred significantly more frequently than deficiencies in other areas. CONCLUSIONS: This study shows that volunteer faculty performed comparably to full-time university faculty in both the frequency of deficiencies in teacher-learner interactions identified and in the types of deficiencies identified. Both university and volunteer faculty had the most deficiencies in higher-order teaching skills--those involving synthesizing and assessing student knowledge and selecting appropriate questions based on that information. Audiotaped case discussions have a potentially significant role in monitoring teacher-student interactions, particularly on decentralized clinical rotations.

Chi-Square Distribution↗
PubMed1996

Ethics and ethnicity: end-of-life decisions in four ethnic groups of cancer patients.

In the United States, principled based ethics has molded bioethics to a large extent. These ethical principles, autonomy, non-maleficence, beneficence, veracity and fidelity used in clinical ethics have embedded in them values and assumptions. This research examined the end-of-life decisions made by or for patients who are Chinese-Americans, Black-Americans, Hispanic-Americans, and Anglo-Americans. Patients, their family care-givers and their health care professionals were interviewed. These interviews plus observations in the cancer clinic raise questions about these principles and asks whether, in an ethnically diverse culture, we need to reflect on ethical absolutes and ethical relativism.

Black or African American↗
PubMed1995

Long-term follow-up of efficacy and safety of megavoltage radiotherapy in high-risk giant cell tumors of bone.

PURPOSE: Giant cell tumors of the bone are rare and have variable presentations and natural history. There may be significant functional sequelae as a result of their locally aggressive nature or as a result of treatment. We reviewed the long-term results of radiotherapy for high risk giant cell tumors to assess: the efficacy of radiotherapy and the potential late toxicity of treatment, and to determine indications for radiation treatment. METHODS AND MATERIALS: This report is a retrospective review of 21 localized giant cell tumors of the bone treated with radiotherapy between 1959 and 1991. Radiation was used in the primary management of 13 cases and for recurrent disease in eight cases. In the primary cases, two received radiotherapy as the sole modality (including a massive pelvic lesion and an advanced maxillary sinus tumor with orbital and pterygoid invasion), and in the other 11, 3 had gross residual disease following surgery and 8 had microscopic residual disease. Of eight recurrent cases, five were treated with radiotherapy alone and three with combined surgery and radiation. Sites of origin included extremity bones in nine cases, pelvis in six, spine in four, and skull in two. Extraosseous disease was apparent in 18 tumors and extended to contiguous structures in 14 (including four cases of spinal cord compression, three cases of sacral plexopathy, and one patient with temporal lobe invasion). The most common dose regimen was 35 Gy/15 fractions/3 weeks (14 cases), with varying schedules for the remainder. RESULTS: Mean follow-up time was 15.4 years (2 to 35 years). Local control was achieved in 19 of 21 patients with radiotherapy. The two failures were subsequently salvaged for an ultimate control rate of 100%. One of the two radiotherapy failures was a marginal failure and was subsequently salvaged with combined surgery and radiotherapy. No patient died of giant cell tumor. Radiotherapy was well tolerated, with no serious late toxicity. There were no cases of malignant transformation or radiation-induced cancer. CONCLUSION: Long-term results in this series indicate that radiotherapy in modest doses (35 Gy in 15 fractions or equivalent) is a safe and effective option for primary and recurrent giant cell tumors of the bone. Radiotherapy should be used if surgery would result in significant functional morbidity and should be considered in select sites where the probability of recurrence is high and there is potential for significant morbidity from tumor relapse or subsequent surgery.

Adolescent↗
PubMed1995

Use of acitretin for the skin complications in renal transplant recipients.

AIM: To review our experience using acitretin for the skin complications in renal transplant recipients. METHODS: Fifteen longterm caucasian renal transplant recipients suffering skin complications were treated with acitretin (10-50 mg daily), a second generation retinoid. Indications for its use were progressive actinic keratoses, widespread warts or recurrent skin malignancies. The therapeutic benefit was assessed by the general condition of of the skin and the number of skin malignancies excised, and the side effects by regular enquiry, skin examination and laboratory tests. RESULTS: All 15 patients reported that the skin became softer and smoother. Actinic keratoses and warts improved or disappeared. Six patients had been on acitretin for over 12 months. The number of malignancies decreased in four of these six patients. Nine patients had cutaneous side effects due to acitretin necessitating a reduction in dose in five patients and discontinuation in the remaining four patients. No patient had any disturbance of their liver or renal function tests or lipid profile. No interaction was found between cyclosporin A and acitretin (seven patients). CONCLUSIONS: Most patients treated with acitretin experienced subjective improvement and actinic keratoses and warts improved or disappeared. Its effect on the skin malignancy rate was variable. Acitretin was reasonably well tolerated. The benefits of this drug remain anecdotal, making a prospective, multicentre, placebo controlled study essential.

Acitretin↗
PubMed1995

Outcome following radiation treatment for high-risk pigmented villonodular synovitis.

PURPOSE: Pigmented villonodular synovitis (PVNS) is a rare proliferative process involving synovial membranes. It has a variable course, and while usually benign, may be destructive, resulting in major symptoms and loss of function leading to amputation. Optimum treatment is not always clear, and little information exists with respect to the role of radiotherapy. The purpose was to review our experience with radiotherapy in cases at high risk for recurrence with functional loss including instances where amputation was the sole alternative for symptomatic disease. METHODS AND MATERIALS: The records of all patients registered between 1972 and 1992 with a diagnosis of PVNS were identified (21 cases). The records of 14 cases who received radiotherapy after referral were reviewed retrospectively for demographic information, radiotherapy treatment parameters, and tumor outcome. RESULTS: All cases had confirmation of pathologic diagnosis. Six patients had primary and eight had recurrent disease (with a mean of 2.5 prior surgical procedures). All cases had both intra- and extraarticular disease and, without exception, the poorer prognosis diffuse subtype of the disease. The majority had one or more additional risk factors including skin, bone, tendon, neurovascular, or muscle group extension. With a mean follow-up time of 69 months (range 13-250 months), only one patient has shown persistence of disease. With the exception of that single case, all those with measurable disease had obvious disease until at least 12 months and, subsequently, manifested complete responses. The single case was lost from the clinic after 8 months from the initiation of radiotherapy to a dose of 30 Gy in 15 fractions and had a palpable mass at the time. He subsequently was noted to have a persisting mass and an excisional biopsy 9 years later showed PVNS. He remains well 21 years after treatment with good function. Eleven patients enjoyed excellent or good function from the affected limb and three had fair function. All patients had greater use of limb than at the time of treatment. No patient required amputation, and none had evidence of serious radiotherapy complications. CONCLUSIONS: These results demonstrate that moderate dose radiotherapy is an effective modality in the treatment of a subset of cases with this rare condition. Its use has permitted avoidance of amputation in very advanced cases with acceptable function preservation. When treatment is indicated we currently recommend gross total removal of PVNS. This is followed by moderate dose radiotherapy (35 Gy in 15 fractions) for residual disease where salvage of subsequent recurrence may compromise function.

Adolescent↗
PubMed1995

Transclavicular approach to the neck, thoracic inlet, and axilla.

OBJECTIVE: To describe claviculotomy and claviculectomy for access to lesions of the lower part of the neck, with simultaneous reconstruction. METHODS AND MATERIALS: A retrospective review of 15 patients who underwent claviculotomy for access to the lower part of the neck. RESULTS: Eight patients underwent plate reconstruction, and one patient required subsequent removal. Three patients underwent total claviculectomy, and four patients underwent partial claviculectomy. Ten patients are alive and free of disease, three have died of disease, and two are alive with disease. All but two patients are satisfied with shoulder function, and one patient is dissatisfied with the cosmetic result. CONCLUSIONS: The claviculotomy and claviculectomy technique for tumors that transgress the neck, thoracic inlet, and axilla offers maximal exposure for excision, vascular control, and preservation of vital structures. Modern plating techniques have allowed clavicular reconstruction with improved cosmesis and preservation of shoulder stability.

Adult↗
PubMed1995

Children who could benefit from a cochlear implant: a European estimate of projected numbers, cost and relevant characteristics.

The incidence of profound hearing impairment by the age of 5, derived from a number of retrospective studies in the UK (population about 58 million; birth rate 14/1000), is estimated to be about 300 per annual birth cohort in the 1990s. This estimate includes 80 children who might be expected to acquire deafness in those first 5 years. Projected to Europe as a whole (population 511 million; birth rate 12/1000) this would mean a population who should be considered as potential cochlear implant patients of some 2268 children, given a variety of assumptions. At a take-up rate of 25% for both congenital and acquired cases of profound hearing impairment this would imply a European-wide expenditure of the order of 17 pounds m/p.a. on hardware and associated rehabilitation programmes. The need for such programmes is explored, in the context of strategies of early identification of hearing impairments.

Child↗
PubMed1995

Complex acetabular reconstruction for metastatic tumor.

Twenty-six hips were reconstructed in 25 patients with periacetabular metastatic lesions. Twelve hip reconstructions were performed using a modified Harrington technique with polymethyl methacrylate, cancellous screws, and reinforcement rings (type I). Fourteen hip reconstructions were performed using bulk bone-graft and reinforcement rings (type II). According to the Musculoskeletal Tumor Society functional rating score, there was no appreciable difference between the two types of reconstructions. Either technique can give satisfactory results depending on the anatomic location and extent of bone loss. Careful patient selection is the prime determinant of a successful outcome.

Acetabulum↗
PubMed1995

Hearing loss and motorcyclists.

Motorcyclists are known to be exposed to excessive wind noise levels when riding. The potential adverse effects of this exposure on their hearing was investigated. Temporary threshold shift (TTS) was assessed by asking 18 riders to undertake a standard test run of one hour at a steady 80 mph, and performing audiometry before and immediately afterwards. Permanent threshold shift (PTS) was assessed by performing pure-tone audiograms on a highly screened group of 246 motorcyclists and comparing their hearing thresholds with those of an appropriate control group obtained from the MRC National Study of Hearing. Significant TTS was found at 0.25, 0.5, 1 and 2 kHz. The greatest TTS occurred at 1 kHz, with a mean hearing loss of 10.3 dB. The hearing thresholds of the motorcyclists were significantly worse than the controls at 0.25, 0.5, 1 and 2 kHz, and was most marked at 0.5 and 1 kHz where their hearing loss (PTS) was, respectively, 3.7 and 3.6 dB greater than expected. These findings demonstrate evidence of both temporary and permanent hearing loss from motorcycling and present a strong argument for the need for some form of remedial action.

Adolescent↗
PubMed1995

Critical factors in the determination of focus group size.

From a theoretical perspective, it is difficult to decide an optimal number of participants that should be included in a focus group. Despite recent attempts, critical factors for the determination of the size of a focus group remain uncertain and can further be elaborated. From a practical perspective, this paper proposes four other factors that can be used for the determination of focus group size. These are: the number of questions asked, the allotted time for each question, the format of the focus group session and the duration of the session. Above all, the size of a group should first be determined by the aims of the research study.

Focus Groups↗
PubMed1995

An evaluation of the action plans of children with asthma.

OBJECTIVE: To assess the provision and use of action plans in children attending hospital because of asthma. METHODOLOGY: An interviewer administered a structured questionnaire to the parents of 279 children attending the Casualty Department, Outpatient clinics or admitted to hospital because of asthma, at two Level 3 teaching hospitals. RESULTS: Only 82 (29%) of the children attending hospital had a written action plan. The majority (57%) were devised by paediatricians and covered the salient aspects of care. However, indications for steroid use were included in only 28% of plans and only 37% of the action plans in children over 5 years incorporated the use of peak flow meters. CONCLUSIONS: Action plans are still under-utilized in children with asthma. General practitioners should be encouraged to consider the use of action plans for the group of children not already covered.

Adolescent↗