Biomedical subjects
Publications and source records attributed to D C Smith.
Writing medical history papers can be professionally and personally rewarding, but a little overwhelming for novices. This paper offers step-by-step guidelines for the entire process, including developing appropriate topics, finding and using appropriate sources, and writing the paper. Specific reference sources are recommended.
BACKGROUND: This paper describes the current nature and distribution of staff making an active contribution to the public health function in Health Authorities in England, so as to assess the extent to which the public health function is truly multidisciplinary and to begin to consider the National Health Service public health capability. METHODS: A pre-piloted questionnaire was administered by Regional Directors of Public Health (RDsPH) to their respective District Directors of Public Health (DDsPH) in all Health Authorities in England over the period June 1995-April 1996. The questionnaire asked for details of all staff in Health Authorities contributing to the public health function as defined by the DDsPH. This provided distributions of: Public Health Physicians; Consultants in Dental Public Health (CsDPH); Trainees in Public Health Medicine (PHM); Epidemiologists; Research Officers; Nurses; Medical Advisers; Pharmacists; Directors of Health Promotion; Others (job titles specific to public health) in Health Authorities in England. RESULTS: Staff contributing to the public health function were distributed as follows: Public Health Physicians (32 per cent); Research or Information Officers and Epidemiologists (16 per cent); Trainees in Public Health Medicine (16 per cent); Nurses (8 per cent); Pharmacists (6 per cent); Medical Advisers (5 per cent); Directors of Health Promotion (4 per cent); Consultants in Dental Public Health (3 per cent); Others (job titles specific to public health) (11 per cent). CONCLUSION: The public health function is multidisciplinary, but the skill mix within Health Authorities is variable. The contribution of all disciplines to Health Authority public health functions needs recognition, not least in the provision of training, accreditation schemes and continuing professional development for all staff so as to secure an effective public health function at local levels to deliver the health agenda.
This retrospective study evaluates the efficacy of megestrol acetate in patients with hormone refractory metastatic adenocarcinoma of the prostate. Data are presented from 14 patients with advanced prostatic adenocarcinoma who were treated with 160-320 mg of megestrol acetate daily. Each patient was either asymptomatic or had minimal cancer-related symptoms. Disease response was monitored by prostate-specific antigen levels. The response rate was 14%, with two patients having a partial response. No complete responses were observed. The median time to disease progression was 2 months. Our findings when considered together with results from previously published data demonstrate little activity of megestrol acetate in patients with hormone refractory prostate cancer. Therefore, we cannot recommend megestrol acetate as an effective second-line therapy.
PURPOSE: Recent studies have suggested that transesophageal echocardiography (TEE) can be used as the primary imaging method in patients suspected of traumatic rupture of the thoracic aorta. A segment of the aorta and the aortic arch branches cannot be adequately evaluated in all patients by TEE. To assess the impact of these limitations of TEE, this retrospective study examined the aortographic features of traumatic aortic or great vessel injuries in a large number of patients. MATERIALS AND METHODS: We retrospectively reviewed clinical and imaging features of 89 patients with a history of blunt chest trauma and angiographic evidence of traumatic injury to the thoracic aorta or to its branches. RESULTS: Of these 89 patients, 72 had aortic rupture alone. One (1%) of these ruptures occurred at the distal ascending aorta, a potential blind spot for TEE. Seventeen patients (19%) had 24 injuries to the aortic arch branches: in 14 of these 17 patients, the aorta was intact, whereas three patients also had aortic rupture. Seventy percent of the injuries to the aortic arch branches were not suspected on physical examination. CONCLUSION: Twenty percent of patients in our retrospective series had traumatic involvement of aortic arch branches or the distal ascending aorta. These vascular injuries may be suboptimally assessed or overlooked if TEE is used as the sole imaging modality in the evaluation of patients with blunt chest trauma.
During the past decade, effective snake antivenoms have become scarce in northern Nigeria. As a result, many patients severely envenomed by the saw-scaled or carpet viper (Echis ocellatus), which is responsible for more than 95% of the snake bites in the region, did not receive effective treatment and mortality and morbidity increased. To combat this crisis, a new monospecific ovine Fab antivenom (EchiTab) is being developed. Its theoretical advantages over conventional equine F(ab')2 antivenom are a more rapid tissue penetration and larger apparent volume of distribution (the volume of [tissue] fluid in which the the antivenom would be uniformly distributed to achieve the observed plasma concentration). In a preliminary study, two vials (20 ml; 1.0 g of protein) of EchiTab rapidly and permanently restored blood coagulability and cleared venom antigenemia in seven envenomed patients. Four experienced early reactions that responded to epinephrine. In a randomized comparative trial of one vial (10 ml; 0.5 g protein) of EchiTab or four ampules (40 ml; 2.12 g of protein) of Institute Pasteur Serum (Ipser) Africa polyspecific F(ab')2 antivenom, there were fewer reactions, but only 36% and 35% of patients, respectively, showed permanent restoration of coagulability, with the remainder requiring further doses. This suggests that 0.5 g (one vial) of EchiTab is approximately equivalent to 2.12 g (four ampules) of Ipser Africa antivenom, and that a higher initial dose will be required for most patients. Measurements of circulating venom and antivenom levels reflected the clinical events.
Almost all patients with metastatic prostate cancer will eventually develop hormone refractory disease. In general, these patients should be enrolled in a clinical trial designed to develop new therapies for the treatment of this disease. However, for a variety of reasons, some patients will not be candidates for these trials. In this setting, a secondary hormonal therapy is a viable option. Secondary hormonal therapy continues and extends the two basic approaches used in primary hormonal therapy: reduction in circulating androgens and competitive inhibition of androgen receptor binding. This article reviews the basic concepts of secondary hormonal therapy, including maintenance of testicular androgen suppression, the anti-androgen withdrawal syndrome, and the available agents. In addition, it reviews hormonal agents currently in development that act by other mechanisms to inhibit prostate cancer growth.
OBJECTIVE: To determine if elective, angiographically directed embolization of enlarged renal angiomyolipomas can be used to prevent future hemorrhagic episodes in patients with tuberous sclerosis and thus avoid nephrectomy. PATIENTS AND METHODS: Records were reviewed for all 5 patients who underwent elective, subtotal embolization of large, symptomatic angiomyolipomas at the authors' institution between 1975 and 1996. RESULTS: All 5 patients had tuberous sclerosis and bilateral renal angiomyolipomas. Initial embolization in these patients was performed in 1975, 1981, 1993 (2 patients) and 1994. In 1 patient only a single embolization session was required. In another, initial embolization on the left side was followed by embolization on the right 13 months later. Two patients underwent 2 sessions, and 1 patient had 4 sessions over a 13-year period. Subtotal embolization with particulate material led to a decrease in size of the most severely affected portion of the kidney. One large angiomyolipoma underwent sterile liquefaction after embolization; percutaneous catheter drainage was required. The embolization allowed subsequent partial nephrectomy in this patient. CONCLUSION: Embolization is effective for the long-term management of renal angiomyolipomas in patients with tuberous sclerosis; in this way nephrectomy and loss of renal function can usually be avoided.
We previously developed a novel and effective therapy for hormone-refractory prostate cancer using the agents estramustine and etoposide. Although neither of these agents alone is effective in the treatment of advanced, hormone-refractory prostate cancer, we predicted their activity when used in combination based on preclinical assays, and then demonstrated their effectiveness in a phase I-II clinical trial, where they were shown to produce a 50% complete and partial response rate in patients with bidimensionally measurable disease. In preclinical studies, we had demonstrated that estramustine and etoposide interact with the nuclear matrix, which is the site of DNA replication. Expanding these investigations, we determined that paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ), a microtubule inhibitor, interacts with estramustine and etoposide, and the combination of these three agents had significant preclinical activity against androgen-independent prostate cancer cells. These studies led us to conduct a phase II clinical trial of paclitaxel, estramustine, and etoposide in patients with hormone-refractory prostate cancer. Preliminary results demonstrate that this is an active regimen, with 57% of patients demonstrating a response to therapy as measured by a decrease in pretreatment prostate-specific antigen levels of greater than 50%.
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BACKGROUND: To determine whether, when primary breast cancer is treated by local excision supported by systemic therapy appropriate to the oestrogen receptor status (ER) of the tumour, local radiotherapy can be avoided. METHODS: We carried out a randomised controlled trial in 585 patients aged less than 70 years with primary breast cancers of 4 cm or less in size in four specialist units and seven other hospitals in Scotland. After local excision of the tumour (1 cm margin) and an axillary lymph-node clearance or sample, all patients received systemic therapy with oral tamoxifen 20 mg daily or six 3-weekly intravenous bolus injections of cyclophosphamide 600 mg, methotrexate 50 mg, and fluorouracil 600 mg per m2, depending upon the ER concentration in the primary tumour. Patients were then randomly allocated to postoperative radical radiotherapy (50 Gy to breast with boost to the tumour bed) or to no further local treatment. The median follow-up of living patients was 5.7 years. The primary analysis was by intention to treat but since some patients did not receive systemic therapy appropriate to their ER status, a subsidiary analysis was restricted to 464 patients in whom all details of the protocol had been observed. FINDINGS: In the primary analysis survival was equal in the radiotherapy and non-radiotherapy groups (hazard ratio [HR] 0.98, 95% CI 0.67-1.44). Event-free survival showed an advantage in the irradiated patients (HR 0.54, 95% CI 0.39-0.74), largely due to fewer loco-regional relapses (HR 0.20, 95% CI 0.12-0.33). The relapse rate in the ipsilateral breast was 24.5% in the non-irradiated group and 5.8% following breast irradiation. The subsidiary analysis confirmed these findings and indicated the advantage of radiotherapy irrespective of ER concentration. There was a non-significant trend towards fewer distant metastases in the irradiated group. INTERPRETATION: After local excision of a primary breast cancer, we conclude that radiotherapy to the residual breast tissue is advisable even when selective adjuvant systemic therapy is given.
OBJECTIVE: To evaluate the effect of support from a nurse specialising in breast care and a voluntary support organisation on prevalence of psychological morbidity after surgery for breast cancer. DESIGN: Prospective randomised study. SETTING: Three teaching hospitals in Glasgow with established breast clinics. SUBJECTS: 272 women aged less than 70 years undergoing surgery for breast cancer. INTERVENTIONS: Patients were randomly allocated to receive routine care from ward staff, routine care plus support from breast care nurse, routine care plus support from voluntary organisation, or routine care plus support from nurse and organisation. MAIN OUTCOME MEASURES: Prevalence of psychological morbidity as assessed by self rating scales: 28 item general health questionnaire and its subscales, and hospital anxiety and depression scale. Measurements were made at first postoperative clinic visit and at three, six, and 12 months after surgery. RESULTS: On each self rating scale, psychological morbidity tended to fall over the 12 month period. For each scale, scores were consistently lower in patients offered support from breast care nurse alone compared with the other groups, which were similar to each other. Differences were significant or nearly so: P values were 0.015 (28 item general health questionnaire), 0.027 (anxiety and insomnia), 0.072 (severe depression), 0.053 (somatic symptoms), 0.031 (social dysfunction), 0.093 (hospital anxiety), and 0.003 (hospital depression). CONCLUSION: Support from breast care nurse can significantly reduce psychological morbidity, as measured by self rating scales, in women undergoing breast cancer surgery.
The purpose of this study was to analyze outcomes of two different treatment strategies in patients treated for renal artery (RA) stenosis and a coincidental abdominal aortic aneurysm (AAA). A total of 50 patients were encountered who required treatment for concomitant RA stenosis and an AAA from 1980 to 1994. Simultaneous operative aortic and RA reconstruction was done in 32 patients, whereas 18 patients where treated with preoperative percutaneous transluminal renal artery angioplasty (PTRA). The two groups were well matched with respect to age, AAA size, incidence of hypertension, preoperative creatinine level, and creatinine clearance (all p values > 0.07). Aortorenal bypass (18 RAs), reimplantation (18 RAs), or endarterectomy (2 RAs) was performed to correct a mean RA stenosis of 88%, whereas 23 RAs (91% mean stenosis) were treated with preoperative PTRA. PTRA failed in four patients with RA stenosis, and they were successfully treated with surgery (3 bypasses and 1 reimplantation). Statistical analysis did not demonstrate a significant difference between these four failed PTRA patients, the 14 successful PTRA patients, and the 32 RA reconstruction patients in terms of operating time (p = 0.15), operative blood loss (p = 0.20), intensive care unit days (p = 0.71), or total hospital days (p = 0.94). Among the 40 patients available for follow-up, hypertension was cured in seven, improved in 10, unchanged in 15, and worse in eight with no difference demonstrated between the groups (p = 0.73). These data suggest that preoperative PTRA has no specific advantage over surgical RA reconstruction in patients with concomitant RA stenosis and AAA. Failed PTRA did not preclude or complicate subsequent operative RA revascularization.
BACKGROUND: Near-infrared spectroscopy is a potential tool for measuring adequacy of cerebral oxygenation during cardiac operations. The cerebral microcirculation is predominantly venous (by volume) and therefore regional cerebral oxygenation measured by near-infrared spectroscopy should reflect jugular bulb venous saturations. METHODS: We compared simultaneous regional cerebral oxygenation and jugular bulb venous saturation measurements in 40 children (median age, 4.5 years; range 2 weeks to 14.5 years) in the cardiac catheter laboratory (n = 29) and during cardiac operations (n = 11). RESULTS: For all patients combined the correlation between regional cerebral oxygenation and jugular bulb venous saturation was 0.69 (p < 0.0001) and was similar for the two groups. For individual children undergoing cardiac operations excellent correlations were obtained (r = 0.78 to 0.96; median, 0.91). However, at low values of jugular bulb venous saturation, regional cerebral oxygenation tended to run high, whereas the converse was true for high values of jugular bulb venous saturation. CONCLUSIONS: These findings suggest that near-infrared spectroscopy may be a useful tool for assessing intravascular cerebral oxygenation during pediatric cardiac operations. Prospective studies of neurologic outcome will be required to establish the value of this technique for assessing the adequacy of cerebral protection.
An ovine affinity purified Fab antivenom was used in a clinical trial in Sweden to treat European adder (Vipera berus berus) envenoming. Immunoassays were developed to measure V. b. berus venom and antivenom concentrations in clinical samples to help assess the efficacy of treatment. A radioimmunoassay (RIA) was developed, optimized and validated to measure plasma levels of V. b. berus venom and compared with a conventional ELISA. Both showed a similar variation of zero binding in biological samples and the results obtained correlated closely. However, the ELISA was quicker and more sensitive (0.8 compared with 2 micrograms/litre). Before administration of antivenom, V. b. berus venom concentrations in plasma ranged from 10 to 53 micrograms/litre; 12 hr after the Fab infusion, no patient had measurable levels. However, two patients had low venom levels 24 hr after treatment. ELISA and RIA were also developed, optimized and used to measure concentrations of free Fab in plasma. There was a biexponential fall of Fab concentration with a fast distribution phase (t 1/2 = 0.9 hr) and a slower elimination phase (t 1/2 = 18 hr). The amount of Fab excreted in urine was low.
OBJECTIVES: Glass ionomer cements are used in clinical dentistry as lining, luting and restorative materials. The precise nature of their bonding mechanism to dentine is unclear. This study is an SEM examination of the effect of the liquid contained in Vitrebond cement (3M Co., MN) on the surface of bovine dentine, with respect to delays in photocuring and washing off with water under pressure or as a gentle stream. The effects of delaying photocuring of the mixed and applied cement for up to 120 s were also examined. RESULTS: The results of this study demonstrated that the liquid component of Vitrebond reacts chemically with dentine in a manner suggestive of an effervescent chemical reaction. This reaction produces plugs in the dentinal tubules which are resistant to dislodgement by water under pressure or by gentle washing. Similarly, a delay in photocuring the mixed and applied cements results in porosity of the cement at the dentine interface. CONCLUSION: The findings in this study suggest that the adhesion of Vitrebond to dentine is primarily chemical in nature and that its mechanical strength is compromised if there are substantial delays in photocuring.
PURPOSE: This study was performed to determine the primary patency, foot salvage, and complication rates associated with iliac artery stent deployment. METHODS: From March 1992 to May 1995, 147 iliac artery stents were deployed in 98 limbs of 72 patients for disabling claudication or limb-threatening ischemia. Procedure-related and late (> 30 days) complications, as well as adjunctive maneuvers required to correct a complication, were tabulated. Stented iliac artery cumulative primary patency and foot salvage rates were calculated with life-table analysis. Factors that impacted early complications, late complications, foot salvage rates, and stented iliac artery primary patency rates were identified with stepwise logistic regression analysis. RESULTS: A procedure-related complication occurred in 19 (19.4%) limbs. Initial technical success, however, was achieved in all but three of 98 limbs (96.9%). Stented iliac artery cumulative primary patency rates were 87.6%, 61.9%, 55.3%, and foot salvage rates were 97.7%, 85.1%, 76.1%, at 12, 18, and 24 months, respectively. External iliac artery stent deployment, superficial femoral artery occlusion before treatment, and single-vessel tibial runoff before treatment negatively affected stented iliac artery cumulative primary patency rates. Stented iliac artery primary patency rates were not significantly affected by age, smoking, coronary artery disease, diabetes, hypercholesterolemia, hypertension, presenting symptom, early complication, number of stents deployed, type of stent deployed, or stent deployment for stenosis versus occlusion. CONCLUSIONS: Limb-threatening and life-threatening complications can be associated with iliac artery stent deployment. Stented iliac artery primary patency rates are affected by distal atherosclerotic occlusive disease and the position of the deployed stent within the iliac system. Stent reconstruction of severe iliac artery occlusive disease is feasible but should be thoughtfully selected.
The subject of this case report is a patient with elevated serum levels of titanium (77 parts/billion [ppb]; normal, 3.3 ppb) and vanadium (0.38 ppb; normal, 0.17 ppb) resulting from excessive wear of a metal-backed patellar component in a total knee arthroplasty. The patellar component was worn through both its polyethylene and metal backing as a result of abnormal contact between the patellar and femoral components. Scanning electron microscopic examination of the ingrowth surface of the patellar component indicated that particle debonding occurred as a result of overloading of the sintered neck regions at the particle-substrate interface, suggesting a possible damage during initial insertion of the device, which may have predisposed it to loosening and abnormal contact with the femoral component. Wear particles resulted in staining of the tissues within the knee and an inflammatory and immune response in the synovium consisting of giant cells and T lymphocytes. The serum metal levels were reduced 22 weeks after replacing the patellar component; however, the titanium level was still slightly elevated (8 ppb).
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