A calibration service for biomedical instrumentation maintenance laboratories

An in-house calibration laboratory for the Biomedical Instrumentation Maintenance Services of the hospitals in the West of Scotland was established in 1993. This paper describes the development of this calibration service in the context of an overall quality system and also estimates its costs. Not only does the in-house service have many advantages but it is shown to be cost effective for workloads exceeding 260 items per annum.

Quality-of-life evaluation in patients receiving treatment for advanced prostate cancer

PURPOSE/OBJECTIVES

To evaluate the quality-of-life (QOL) experience in patients who are receiving treatment for advanced prostate cancer and the relationship between response to that treatment and QOL.

DESIGN

Descriptive comparative study, repeated measures.

SETTING

Medical oncology clinic in a comprehensive cancer center.

SAMPLE

33 patients receiving treatment for advanced prostate cancer.

METHODS

Patient self-administered questionnaires and chart review.

MAIN RESEARCH VARIABLES

Response to therapy and QOL.

FINDINGS

No significant differences were seen in patients at the baseline evaluation. Patients who demonstrated response to therapy based on declining prostate specific antigen levels, however, demonstrated a significant increase in their QOL scores compared to those patients who were not responding to treatment.

CONCLUSIONS

Although significant differences in survival at this stage of prostate cancer in patients who receive therapeutic treatment versus those who do not have yet to be demonstrated, there appears to be a benefit in QOL for those patients who respond to therapy.

IMPLICATIONS FOR NURSING PRACTICE

These data support the use of QOL measurements in patients undergoing treatment for advanced prostate cancer. This information can be used in discussions with patients who are facing treatment decisions and who are concerned about the impact of treatment on their overall QOL. The data also stimulate questions for future research on QOL in this population, such as the difference in QOL in those patients who choose therapeutic treatment versus those who do not.

Enhanced recognition memory following vagus nerve stimulation in human subjects

Neuromodulators associated with arousal modulate learning and memory, but most of these substances do not freely enter the brain from the periphery. In rodents, these neuromodulators act in part by initiating neural messages that travel via the vagus nerve to the brain, and electrical stimulation of the vagus enhances memory. We now extend that finding to human verbal learning. We examined word-recognition memory in patients enrolled in a clinical study evaluating the capacity of vagus nerve stimulation to control epilepsy. Stimulation administered after learning significantly enhanced retention. These findings confirm in humans the hypothesis that vagus nerve activation modulates memory formation similarly to arousal.

Are changes in the evoked electromyogram during anaesthesia without neuromuscular blocking agents caused by failure of supramaximal nerve stimulation?

The evoked electromyogram often decreases during anaesthesia in the absence of neuromuscular block. We have measured the electromyogram of the first dorsal interosseous muscle evoked by train-of-four stimulation of the ulnar nerve in 63 patients undergoing anaesthesia for minor surgery. We used Medicotest P-00-S electrodes, a Datex Relaxograph and a current sink in the stimulating leads in parallel with the current path through the patient. The current sink was used to shunt some of the maximum available output current from the Relaxograph while maintaining the supramaximal stimulus current passing through the patient. After 30 min of anaesthesia, when the muscle response to train-of-four was stable, the ulnar nerve stimulus current was increased by reducing the proportion shunted through the current sink. The electromyographic response did not change during the study in 13 patients. In the remaining 50 patients, the response decreased to 78.4% (SD 27.1%, range 7.5-95.0%) of baseline values over the first 20 min of anaesthesia. In 22 of these patients, the electromyographic response increased from 71.4 (SD 22.6)% to 92.3 (9.5)% of baseline responses when the stimulus current was increased by 12.3 (2.4) mA, while in the remaining 28 patients the response decreased to 83.7 (10.6)% and did not increase with increasing stimulus current. These results suggest that loss of supramaximal stimulation is partly responsible for the observed changes in the evoked electromyogram during anaesthesia.

Posttraining electrical stimulation of vagal afferents with concomitant vagal efferent inactivation enhances memory storage processes in the rat

Peripherally administered or released substances that modulate memory storage, but do not freely enter the brain, may produce their effects on memory by activating peripheral receptors that send messages centrally through the vagus nerve. Indeed, vagus nerve stimulation enhances memory performance, although it is unclear whether this effect is due to the activation of vagal afferents or efferents. To eliminate the possible influence of descending fibers on memory storage processes, rats were implanted with cuff electrode/catheter systems along the left cervical vagus. Forty-eight hours following surgery, each animal received a 3. 0-microliter infusion (1.0 microliter/min) of either lidocaine hydrochloride (75.0 mM) or isotonic saline below the point of stimulation. Animals were then trained 10 min later on an inhibitory-avoidance task with a 0.75-mA, 1.0-s foot shock. Sham stimulation or vagus nerve stimulation (0.5-ms biphasic pulses; 20.0 Hz; 30 s; 0.2, 0.4, or 0.8 mA) was administered immediately after training. Memory, tested 24 h later, was enhanced by stimulation whether descending vagus nerve fibers were inactivated or not. Both lidocaine- and saline-infused groups showed an intensity-dependent, inverted-U-shaped pattern of retention performance, with the greatest effect observed for 0.4 mA (U = 9, p < .05, and U = 7, p < .01, respectively). Additionally, animals that received lidocaine infusions, but no vagus nerve stimulation, showed impaired memory compared to the performance of saline-infused control animals (U = 11, p < .05). Together, these findings suggest that vagal afferents carry messages about peripheral states that lead to the modulation of memory storage and that the memory-enhancing effect produced by vagus nerve stimulation is not mediated via the activation of vagal efferents.

Trauma to the aorta and aortic arch branches

Deceleration and crushing injuries of the chest may traumatize the thoracic aorta or its branches. Traumatic aortic rupture has received significant attention over the past 40 years, whereas the aortic arch branch injuries remain under-recognized. Despite the development of new imaging modalities, angiography remains the gold standard for evaluation of a patient with suspected thoracic arterial injury. Recently, computed tomography and transesophageal echocardiography have been used for serial examination of minimal aortic injuries that are treated conservatively. Medical treatment of the ruptured aorta, delayed surgical repair, and endoluminal deployment of stent-grafts are new developments that provide new options and pose new questions in the management of thoracic arterial injuries.

A phase II trial of oral diethylstilbesterol as a second-line hormonal agent in advanced prostate cancer

OBJECTIVES

To test the use of 1 mg/day of oral diethylstilbesterol (DES) as a treatment for patients with advanced prostate cancer who had failed primary hormonal therapy. Approximately 40,000 men this year will experience first-line hormonal therapy failure for their metastatic prostate cancer. At this time there is no standard therapy for men whose first-line hormonal manipulation has failed. This clinical problem has been exacerbated by the use of prostate-specific antigen (PSA) as a proved biomarker to follow disease progression. Patients who are experiencing hormonal therapy failure now present with a rising PSA, and virtually all are asymptomatic. The dilemma of how to treat these patients represents a new clinical problem for the medical oncologist and urologist that needs to be answered.

METHODS

We conducted a Phase II trial of oral DES in 21 patients. Patients were followed for response by PSA criteria and toxicity. A decrease in two serial measurements of PSA of greater than 50% from baseline was judged to be a partial response.

RESULTS

Nine of 21 patients achieved a PSA response (43% response rate with 95% confidence intervals of 22% to 64%) leading to early cessation of this Phase II trial. Eight of 13 patients (62%) who had only one prior hormone manipulation that failed demonstrated a PSA response, whereas only 1 of 8 patients (13%) who had received two or more hormone treatments responded (P = 0.07). The median follow-up is 82 weeks (range 8 to 122) among 16 surviving patients. The survival rate at 2 years is 63% (95% confidence interval 41% to 99%).

CONCLUSIONS

DES appears to be an active agent for second-line hormone therapy for metastatic prostate cancer. Because it has been taken off the market for economic reasons, DES should be considered for development under the orphan drug strategy.

Breast milk contamination and silicone implants: preliminary results using silicon as a proxy measurement for silicone

In response to concerns about contamination of human breast milk from silicone gel-filled breast implants, and because silicon levels are assumed to be a proxy measurement for silicone, we compared silicon levels in milk from lactating women with and without implants. Two other sources of infant nutrition, cow's milk and infant formulas, were also analyzed for silicon. The survey took place at the Breast-feeding Clinic at Women's College Hospital in Toronto. A convenience sample of lactating women, 15 with bilateral silicone gel-filled implants and 34 with no implants, was selected. Women with foam-covered or saline implants or with medically related silicone exposures were ineligible. Collection of samples was scrupulously controlled to avoid contamination. Samples were prepared in a class 100 "ultraclean" laboratory and analyzed using graphite furnace atomic absorption spectrophotometry. Silicon levels were analyzed in breast milk, whole blood, cow's milk, and 26 brands of infant formulas. Comparing implanted women to controls, mean silicon levels were not significantly different in breast milk (55.45 +/- 35 and 51.05 +/- 31 ng/ml, respectively) or in blood (79.29 +/- 87 and 103.76 +/- 112 ng/ml, respectively). Mean silicon level measured in store-bought cow's milk was 708.94 ng/ml, and that for 26 brands of commercially available infant formula was 4402.5 ng/ml (ng/ml = parts per billion). We concluded that lactating women with silicone implants are similar to control women with respect to levels of silicon in their breast milk and blood. Silicon levels are 10 times higher in cow's milk and even higher in infant formulas.

Locus coeruleus lesions suppress the seizure-attenuating effects of vagus nerve stimulation

PURPOSE

Although vagus nerve stimulation (VNS) is now marketed throughout most of the world as a treatment for drug-resistant epilepsy, the therapeutic mechanism of action of VNS-induced seizure suppression has not yet been established. Elucidation of this mechanism is an important first step in the development of strategies to improve VNS efficacy. Because the locus coeruleus (LC) has been implicated in the antinociceptive effects of VNS, we chemically lesioned the LC in the present study to determine if it is a critical structure involved in the anticonvulsant mechanisms of VNS.

METHODS

Rats were chronically depleted of norepinephrine (NE) by a bilateral infusion of 6-hydroxydopamine (6-OHDA) into the LC. Two weeks later, they were tested with maximal electroshock (MES) to assess VNS-induced seizure suppression. In another experiment, the LC was acutely inactivated with lidocaine, and seizure suppression was tested in a similar fashion.

RESULTS

VNS significantly reduced seizure severities of control rats. However, in animals with chronic or acute LC lesions, VNS-induced seizure suppression was attenuated.

CONCLUSIONS

Our data indicate that the LC is involved in the circuitry necessary for the anticonvulsant effects of VNS. Seizure suppression by VNS may therefore depend on the release of NE, a neuromodulator that has anticonvulsant effects. These data suggest that noradrenergic agonists might enhance VNS-induced seizure suppression.

Femtosecond infrared pulses tunable from 9 to 18 mum at an 88-MHz repetition rate

Femtosecond mid-infrared laser pulses that are continuously tunable in the wavelength range from 9 to 18mum are demonstrated. These nearly bandwidth-limited pulses are generated by phase-matched difference-frequency mixing within the broad spectrum of 20-fs pulses from a mode-locked Ti:sapphire laser in GaSe. A direct determination of the pulse duration at 11.5mum gives a value of 140 fs. The average mid-infrared power of 1muW is ~100 times greater than that for infrared generation by non-phase-matched optical rectification.

Change in serum prostate-specific antigen as a marker of response to cytotoxic therapy for hormone-refractory prostate cancer

PURPOSE

Prostate-specific antigen (PSA) has been used as a marker of advanced prostate cancer but remains controversial. To evaluate PSA as a predictor of survival, we analyzed data from sequential phase II trials of estramustine and etoposide.

METHODS

A landmark analysis that used data from 62 men with PSA levels at baseline and 8 weeks was conducted. The best PSA measure (of six evaluated) was incorporated into a multiple regression model with performance status (PS); relative change in PSA level; and pretreatment PSA, alkaline phosphatase, and hemoglobin values.

RESULTS

A decrease in PSA of 50% or greater at 8 weeks was associated with a significantly increased survival (P=.0005, two-sided log-rank test). Median survival from the landmark was 91 weeks in patients with a 50% or greater decrease at 8 weeks versus 38 weeks in those without this decrease. Modeling showed that PS, pretreatment hemoglobin level, and relative change in PSA level were significant prognostic factors, with a significant interaction between PS and pretreatment hemoglobin level. In the final model, a relative change in PSA level at 8 weeks of less than 50% had an adjusted relative risk of 2.20 (95% confidence interval, 1.21 to 4.00). A decrease in PSA level of 50% or greater at any time during therapy was associated with a response in measurable disease (P=.0369, two-sided Fisher's exact test).

CONCLUSION

The PSA value after 8 weeks of this cytotoxic regimen does predict survival. A decrease in PSA level is associated with both survival and response in soft tissue lesions and should be incorporated into the response criteria and reporting of trials of cytotoxic agents in prostate cancer.

Phase II trial of paclitaxel and carboplatin in the treatment of advanced urothelial carcinoma

PURPOSE

Both paclitaxel and carboplatin have single-agent activity against carcinoma of the urothelium. We evaluated the combination of paclitaxel and carboplatin in the treatment of advanced cancers of the urothelium.

PATIENTS AND METHODS

Patients with cancers of the urothelium who had no prior chemotherapy (prior adjuvant chemotherapy > 6 months allowed) were eligible for treatment. Eligibility requirements were performance status of 2 or less, creatinine level less than 2.0 mg/dL, granulocyte count (AGC) 1,500/microL or greater, platelet count 100,000/microL or greater, and total bilirubin level less than 1.5 mg/dL. Paclitaxel 200 mg/m2 followed by carboplatin (area under the curve [AUC] 5, Calvert formula) were administered every 21 days. Patients were evaluated for toxicity weekly and assessed for response every 6 weeks.

RESULTS

Thirty-six patients were entered onto the study and 35 patients were assessable for response. A total of 184 cycles were administered (median, six cycles per patient). Nine patients required one dose reduction, and seven patients required two dose reductions for a nadir AGC less than 500/microL, with only one episode of febrile neutropenia and sepsis. Myalgias and arthralgias of grades 1 to 2 occurred in 16 patients and usually lasted 2 to 3 days after treatment. There were no treatment delays because of toxicity. There were 18 responses; seven complete responses (CRs) and 11 partial responses (PRs) (response rate 51.5%; 95% confidence interval, 35 to 68). Median response durations for CR and PR were 6 and 4 months, respectively. Overall median survival was 9.5 months.

CONCLUSION

The combination of paclitaxel and carboplatin is an active and well-tolerated regimen for the treatment of advanced urothelial carcinoma. Because of the modest toxicity of this combination, paclitaxel and carboplatin should be considered for addition to other agents with activity in urothelial carcinomas.

Cerebral oxygenation during paediatric cardiac surgery: identification of vulnerable periods using near infrared spectroscopy

OBJECTIVE

Neurologic sequelae remain a well recognised complication of paediatric cardiac surgery. Monitoring of cerebral oxygenation may be a useful technique for identifying vulnerable periods for the development of neurologic injury. We sought to measure regional cerebral oxygenation in children undergoing cardiac surgery using near infrared spectroscopy to ascertain such vulnerable periods.

METHODS

Observational study of 18 children (median age 1.3 years) undergoing cardiac surgery (17 with cardiopulmonary bypass, 8 with circulatory arrest). Regional cerebral oxygenation was monitored using the INVOS 3100 cerebral oximeter and related to haemodynamic parameters at each stage of the procedure.

RESULTS

Prior to the onset of bypass, 10 patients had a decrease in regional cerebral oxygenation of > or = 15% points, reaching an absolute haemoglobin saturation less than 35% in 5 cases. The most common cause was handling and dissection around the heart prior to and during caval cannulation. With institution of bypass, regional cerebral oxygenation increased by a mean 18% points to a mean maximum of 75%. During circulatory arrest regional cerebral oxygenation decreased with rate of decay influenced by temperature at onset of arrest (0.25%/min at < 20 degrees C; 2%/min at > 20 degrees C). Reperfusion caused an immediate increase in regional cerebral oxygenation followed by a decrease during rewarming. Discontinuation of bypass caused a precipitous decrease in regional cerebral oxygenation in 5 patients, reaching less than 50% in 3 patients.

CONCLUSIONS

These observations suggest that the pre- and early post-bypass periods are vulnerable times for provision of adequate cerebral oxygenation. Near infrared spectroscopy is a promising tool for monitoring O2 supply/demand relationships especially during circulatory arrest.

Expression of mutant dynamin protects cells against diphtheria toxin but not against ricin

Diphtheria toxin is believed to enter sensitive mammalian cells via receptor-mediated endocytosis from clathrin-coated pits, while ricin can enter via both clathrin-dependent and clathrin-independent endocytosis. The present study has confirmed this by determining the toxin sensitivity of COS-7y cells which were transiently overexpressing a trans dominant negative mutant of dynamin, a GTPase required for the budding of clathrin-coated vesicles from the plasma membrane. Cells overexpressing wild-type dynamin showed normal receptor-mediated endocytosis of transferrin and remained sensitive to both diphtheria toxin and ricin. Cells overexpressing a mutant dynamin defective in GTP binding and hydrolysis were unable to endocytose transferrin and were protected against diphtheria toxin, but they remained completely sensitive to ricin intoxication. Treating non-transfected cells or cells overexpressing mutant dynamin with nystatin caused a redistribution of the caveolae membrane marker protein VIP21-caveolin from the cell surface to intracellular locations, but did not affect their sensitivity to ricin. The redistribution of caveolin seen after nystatin treatment may reflect the disappearance of caveolae. If this is the case, caveolae are not responsible for the endocytosis of ricin. An alternative clathrin-independent route may operate for ricin, since cellular uptake, intracellular transport, and translocation into the cytosol remain unaffected when clathrin-dependent endocytosis is effectively blocked.

Development of glass-ionomer cement systems

In the 1960s the idea of positive physico-chemical adhesion with tooth substance resulted in the invention of polyacrylic acid-based cements, first the zinc polycarboxylate and, subsequently, the glass-ionomer cements. These materials were shown to undergo specific adhesion with hydroxyapatite and proved to have properties satisfactory for a variety of clinical applications. The key properties of the glass-ionomer cements--fluoride release over a prolonged period and specific adhesion to enamel and dentine coupled with aesthetic qualities are related to their characteristics as aqueous polyelectrolyte systems. In order to improve toughness, speed of setting and resistance to dehydration, hybrid materials in which some of the water content of the glass-ionomer system was replaced by water-soluble polymers or monomer systems capable of ambient polymerization were formulated in the late 1980s. These materials, which have been termed resin-modified glass-ionomer cements, involve, ideally, the formation of an interpenetrating polymer network combining the acid-base cross-linking reaction of the metal ion-polyacid with the cross-linking polymerization of the monomer system or additive action of the polymers. In the predominantly resin materials there is little polyelectrolyte character and it is controversial whether such materials should be categorized as glass-ionomer cement systems. The specific advantages of these materials over traditional glass-ionomer systems and over composite restorative systems remain to be fully documented. Studies of adsorption to hydroxyapatite of typical monomers using X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (TOF SIMS) indicate that resistance to water displacement decreases as hydrophobicity increases.

All-trans-retinoic acid modulation of drug-metabolizing enzyme activities: investigation with selective metabolic drug probes

PURPOSE

All-trans-retinoic acid (ATRA) is a retinoid analogue that has been shown to be effective in acute promyelocytic leukemia. It is currently being investigated for efficacy in the treatment and prevention of various types of cancer. One of the factors limiting its use is the observed increase in ATRA clearance and elimination which occurs shortly after treatment is started, leading to reduced levels of drug in the body and loss of effectiveness. ATRA efficacy may be enhanced if this autoinduction of metabolism can be overcome, for example through the inhibition of the activity of the induced specific metabolizing enzyme(s). This requires the identification of this induced enzyme(s) and development of approaches to selectively inhibit its activity.

METHODS

In the course of a phase II evaluation of ATRA in prostate cancer, we investigated the activities of five specific cytochrome P450 (CYP) (CYPs 1A2, 2C19, 2D6, 2E1 and 3A4) and N-acetyltransferase enzymes using a newly developed five-drug cocktail involving caffeine, mephenytoin, debrisoquine, chlorzoxazone and dapsone respectively. Enzyme activities were assessed in 17 patients with hormone-refractory prostate cancer before the initiation of ATRA therapy, after 14 days of continuous ATRA administration and 7 days after cessation of drug therapy.

RESULTS

After 14 days of ATRA therapy, the activities of CYP2E1 (chlorzoxazone hydroxylase) and N-acetyltransferase (in fast acetylators only) were increased by 83% and 29% (P < 0.05), respectively. Both activities returned to baseline by 7 days after cessation of therapy and the profiles were similar to the changes seen in the clearance of ATRA itself. There were no changes in the activities of any of the other enzymes investigated.

CONCLUSION

This study shows that ATRA selectively modulates the activities of specific metabolizing enzymes and that this approach may be useful in identifying enzymes that can be explored in an attempt to mitigate ATRA autoinduction through selective modulation of enzyme activities. Further investigations are required to determine whether the elevated enzymes are also responsible for the increased clearance and elimination of ATRA.

Enhancement of 1,25-dihydroxyvitamin D3-mediated antitumor activity with dexamethasone

BACKGROUND

The active metabolite of vitamin D, i.e., 1,25-dihydroxycholecalciferol (1,25-D3), inhibits the growth of murine SCCVII/SF squamous cell carcinoma cells, both in vitro and in vivo. However, in vivo use of 1,25-D3 is hampered as a result of hypercalcemia (i.e., elevated levels of calcium in the blood). Glucocorticoids, such as dexamethasone, affect calcium absorption and modulate vitamin D receptor binding and have been used to treat hypercalcemia. In this study, we examined the effect of dexamethasone on tumor growth inhibition by 1,25-D3.

METHODS

The effects of 1,25-D3 and dexamethasone, alone and in combination, on the growth of SCCVII/SF cells in in vitro culture or in vivo in female C3H/HeJ mice were determined by clonogenic tumor cell assay and/or by actual changes in tumor volume. Vitamin D receptor-ligand-binding activities in whole-cell extracts from cells (in culture), tumors, and normal tissues were assayed by single-point saturation analysis and equilibrium binding.

RESULTS

Treatment of cultured SCCVII/SF cells with 500 nM dexamethasone for 24 hours before addition of 1,25-D3 reduced their survival. The growth of SCCVII/SF tumors was inhibited in mice treated simultaneously with dexamethasone and 1,25-D3 (as compared with no treatment or single-agent treatment); hypercalcemia was also reduced. Total vitamin D receptor content in SCCVII/SF cells was increased after treatment with dexamethasone. Treatment of tumor-bearing animals with dexamethasone (9 microg/day) for 7 days led to increased vitamin D receptor-ligand-binding activities in whole-cell extracts from tumor or kidneys and decreased activity in intestinal mucosa.

CONCLUSIONS

Dexamethasone may enhance the antitumor effect of 1,25-D3 by increasing vitamin D receptor-ligand-binding activity.

On writing medical history

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.

Who contributes to the public health function?

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.

Systemic metal ion levels in dental implant patients

Metal ion release from metallic implants is known to occur, but its extent and implications are controversial. In spite of the rapidly growing use of such implants, little is known about metal ion release. Blood levels of titanium, aluminum, and vanadium were measured using an atomic absorption spectrophotometric technique preoperatively and at intervals over a 3-year period for 52 patients (17 men, 35 women), each of whom had three mandibular porous-surface endosseous dental implants. The results showed that there was no evidence of change from preoperative to long-term values for the three metals measured in the study. These findings are reassuring, but do not rule out local or remote accumulation of released ions, which was not measured in this study.

Paclitaxel, estramustine, and etoposide in the treatment of hormone-refractory prostate cancer

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%.

A phase II trial of oral estramustine and oral etoposide in hormone refractory prostate cancer

OBJECTIVES

We previously demonstrated that the combination of oral estramustine (15 mg/kg/day) and oral etoposide (50 mg/m2/day) is effective first-line therapy for the treatment of hormone refractory prostate cancer. We initiated a new Phase II trial utilizing a lower dose of estramustine (10 mg/kg/day) and allowing previous chemotherapy treatment.

METHODS

Estramustine (10 mg/kg/day) and etoposide (50 mg/m2/day) were administered orally for 21 of 28 days. Sixty-two patients were enrolled with a minimum of 26 weeks of follow-up.

RESULTS

Of 15 patients with measurable soft tissue disease, 8 (53%) had a partial response (PR). Seven of these 8 patients also demonstrated a decrease in baseline prostate-specific antigen (PSA) of more than 50%. The median survival of all patients was 56 weeks. Of 47 patients with disease limited to the bone, 16 (34%) had a PR to therapy based on decrease in pretreatment PSA of more than 50%. Overall, 24 (39%) of 62 patients demonstrated a decrease in pretreatment PSA levels of at least 50% from baseline. Twenty-two patients received previous chemotherapy. There were no differences in survival or disease response in patients treated with previous chemotherapy compared with untreated patients. Pretreatment hemoglobin, PSA, alkaline phosphatase and lactate dehydrogenase levels were not significant prognostic factors, but performance status was an important predictor of survival.

CONCLUSIONS

We conclude that the combination of oral estramustine (10 mg/kg/day) and oral etoposide (50 mg/m2/day) is an active regimen for hormone refractory prostate cancer.