Loss of LCMT1 and biased protein phosphatase 2A heterotrimerization drive prostate cancer progression and therapy resistance

Loss of the tumor suppressive activity of the protein phosphatase 2A (PP2A) is associated with cancer, but the underlying molecular mechanisms are unclear. PP2A holoenzyme comprises a heterodimeric core, a scaffolding A subunit and a catalytic C subunit, and one of over 20 distinct substrate-directing regulatory B subunits. Methylation of the C subunit regulates PP2A heterotrimerization, affecting B subunit binding and substrate specificity. Here, we report that the leucine carboxy methyltransferase (LCMT1), which methylates the L309 residue of the C subunit, acts as a suppressor of androgen receptor (AR) addicted prostate cancer (PCa). Decreased methyl-PP2A-C levels in prostate tumors is associated with biochemical recurrence and metastasis. Silencing LCMT1 increases AR activity and promotes castration-resistant prostate cancer growth. LCMT1-dependent methyl-sensitive AB56αCme heterotrimers target AR and its critical coactivator MED1 for dephosphorylation, resulting in the eviction of the AR-MED1 complex from chromatin and loss of target gene expression. Mechanistically, LCMT1 is regulated by S6K1-mediated phosphorylation-induced degradation requiring the β-TRCP, leading to acquired resistance to anti-androgens. Finally, feedforward stabilization of LCMT1 by small molecule activator of phosphatase (SMAP) results in attenuation of AR-signaling and tumor growth inhibition in anti-androgen refractory PCa. These findings highlight methyl-PP2A-C as a prognostic marker and that the loss of LCMT1 is a major determinant in AR-addicted PCa, suggesting therapeutic potential for AR degraders or PP2A modulators in prostate cancer treatment.

Gamma knife radiosurgery of meningiomas involving the foramen magnum

Background:

Foramen magnum meningiomas represent a challenging clinical entity. Although resection is performed for those with a mass effect, complete resection is not always feasible. For some patients, stereotactic radiosurgery may be used as the primary treatment modality. We evaluatedthe long-term outcome of Gamma Knife radiosurgery (GKRS) for the treatment of patientswith a foramen magnum meningioma.

Materials and Methods:

Between 1991 and 2005, 222 patients with a meningioma in the posterior fossa were treated with GKRS at the University of Virginia. Of these patients, 5 had meningiomas involving the foramen magnum. At the time of GKRS, the median age of the patients was 60 years (range, 51–78). Three patients were treated with radiosurgery following an initial resection and 2 were treated with upfront radiosurgery. The patients were assessed clinically and radiologically at routine intervals following GKRS.

Results:

The median tumor volume was 6.8 cc (range 1.9–17 cc). The GKRS tumor received a marginal dose of 12 Gy (range 10–15), and the median number of isocenters was 5 (range 3–19). The mean follow-up was 6 years (range 4–13). One lesion increased in size following GKRS requiring a second treatment, resulting in size stabilization. At the time of the last follow-up, all meningiomas had either demonstrated no growth (n = 4) or reduction in size (n = 1). No patients experienced post-radiotherapy complications.

Conclusions:

GKRS affords a high rate of tumor control and preservation of neurologic function for patients with foramen magnum meningiomas. Further study of its role in the neurosurgical management of such patients seems warranted.

Gamma Knife surgery of meningiomas located in the posterior fossa: factors predictive of outcome and remission

Object

Although numerous studies have analyzed the role of stereotactic radiosurgery for intracranial meningiomas, few studies have assessed outcomes of posterior fossa meningiomas after stereotactic radiosurgery. In this study, the authors evaluate the outcomes of posterior fossa meningiomas treated with Gamma Knife surgery (GKS). The authors also assess factors predictive of new postoperative neurological deficits and tumor progression.

Methods

A retrospective review was performed of a prospectively compiled database documenting the outcomes of 152 patients with posterior fossa meningiomas treated at the University of Virginia from 1990 to 2006. All patients had a minimum follow-up of 24 months. There were 30 males and 122 females, with a median age of 58 years (range 12–82 years). Seventy-five patients were treated with radiosurgery initially, and 77 patients were treated with GKS after resection. Patients were assessed clinically and radiographically at routine intervals following GKS. Factors predictive of new neurological deficit following GKS were assessed via univariate and multivariate analysis, and Kaplan-Meier analysis and Cox multivariate regression analysis were used to assess factors predictive of tumor progression.

Results

Patients had meningiomas centered over the tentorium (35 patients, 23%), cerebellopontine angle (43 patients, 28%), petroclival region (28 patients, 18%), petrous region (6 patients, 4%), and clivus (40 patients, 26%). The median follow-up was 7 years (range 2–16 years). The mean preradiosurgical tumor volume was 5.7 cm3 (range 0.3–33 cm3), and mean postradiosurgical tumor volume was 4.9 cm3 (range 0.1–33 cm3). At last follow-up, 55 patients (36%) displayed no change in tumor volume, 78 (51%) displayed a decrease in volume, and 19 (13%) displayed an increase in volume. Kaplan-Meier analysis demonstrated radiographic progression-free survival at 3, 5, and 10 years to be 98%, 96%, and 78%, respectively. In Cox multivariable analysis, pre-GKS covariates associated with tumor progression included age greater than 65 years (hazard ratio [HR] 3.24, 95% CI 1.12–9.37; p = 0.03) and a low dose to the tumor margin (HR 0.76, 95% CI 0.60–0.97; p = 0.03), and post-GKS covariates included shunt-dependent hydrocephalus (HR 25.0, 95% CI 3.72–100.0; p = 0.001). At last clinical follow-up, 139 patients (91%) demonstrated no change or improvement in their neurological condition, and 13 patients showed symptom deterioration (9%). In multivariate analysis, the only factors predictive of new or worsening symptoms were clival or petrous location (OR 4.0, 95% CI 1.1–13.7; p = 0.03).

Conclusions

Gamma Knife surgery offers an acceptable rate of tumor control for posterior fossa meningiomas and accomplishes this with a low incidence of neurological deficits. In patients selected for GKS, tumor progression is associated with age greater than 65 years and decreasing dose to the tumor margin. Clival- or petrous-based locations are predictive of an increased risk of new or worsening neurological deficit following GKS.

Gamma Knife surgery for parasellar meningiomas: long-term results including complications, predictive factors, and progression-free survival

OBJECT

Stereotactic radiosurgery serves as an important primary and adjuvant treatment option for patients with many types of intracranial meningiomas. This is particularly true for patients with parasellar meningiomas. In this study, the authors evaluated the outcomes of Gamma Knife surgery (GKS) used to treat parasellar meningiomas.

METHODS

The study is a retrospective review of the outcomes in 138 patients with meningiomas treated at the University of Virginia from 1989 to 2006; all patients had a minimum follow-up of 24 months. There were 31 men and 107 women whose mean age was 54 years (range 19-85 years). Eighty-four patients had previously undergone resection. The mean pre-GKS tumor volume was 7.5 ml (range 0.2-54.8 ml). Clinical and radiographic evaluations were performed, and factors related to favorable outcomes in each case were assessed.

RESULTS

The mean follow-up duration was 84 months (median 75.5 months, range 24-216 months). In 118 patients (86%), the tumor volume was unchanged or had decreased at last follow-up. Kaplan-Meier analysis demonstrated radiographic progression-free survival at 5 and 10 years to be 95.4% and 69%, respectively. Fourteen patients (10%) developed new cranial nerve palsies following GKS. Factors associated with tumor control included younger age, a higher isodose, and smaller tumor volume. A longer follow-up duration was associated with either a decrease or increase in tumor volume. Fourteen patients (10%) experienced new or worsening cranial nerve deficits after treatment. Factors associated with this occurrence were larger pretreatment tumor volume, lower peripheral radiation dose, lower maximum dose, tumor progression, and longer follow-up.

CONCLUSIONS

Gamma Knife surgery offers an acceptable rate of tumor control for parasellar meningiomas and accomplishes this with a low incidence of neurological deficits. Radiological control after radiosurgery is more likely in those patients with a smaller tumor volume and a higher prescription dose.

Temozolomide-induced inhibition of pituitary adenoma cells

Object

Aggressive pituitary adenomas frequently require multimodality treatment including pituitary-suppressive medications, microsurgery, and radiation therapy or radiosurgery. The effectiveness of temozolomide in terms of growth suppression and decreased hormonal production is evaluated.

Methods

Three pituitary adenoma cell lines—MMQ, GH3, and AtT20—were used. A dose escalation of temozolomide was performed for each cell line, and inhibition of cell proliferation was assessed using an MTT assay. Concentrations of temozolomide that produced statistically significant inhibition of cell proliferation for each cell type were identified. Extent of apoptosis for each selected temozolomide concentration was studied using TUNEL staining. The effect of temozolomide on prolactin secretion in MMQ and GH3 cells was also measured via ELISA.

Results

Significant inhibition of cell proliferation was noted for MMQ and GH3 cells at a concentration of 250 μM temozolomide. The AtT20 cells demonstrated statistically significant cell inhibition at a concentration of only 50 μM temozolomide (p < 0.05). Apoptosis significantly increased in all cell lines in as little as 24 hours of incubation at the respective temozolomide concentrations (p < 0.05). Prolactin secretion in the prolactin secreting MMQ and GH3 cell lines was inhibited by 250 μM temozolomide.

Conclusions

Temozolomide inhibits cell proliferation and induces apoptotic cell death in aggressive pituitary adenoma cells. A reduction in hormonal secretion in prolactinoma cells was also afforded by temozolomide. Temozolomide may prove useful in the multimodality management of aggressive pituitary adenomas.

Gamma knife radiosurgery of tentorial meningiomas

OBJECTIVE

Tentorial meningiomas are complex lesions that may not always be completely resected without significant morbidity or mortality. In this study, we evaluate the outcomes of tentorial meningiomas treated with Gamma Knife radiosurgery (GKRS).

METHODS

We performed a retrospective review of a prospectively compiled database evaluating the outcomes of 35 patients with tentorial meningiomas treated at the University of Virginia from 1990 to 2006. There were 29 females and 6 males with a median age of 60 years (range 21-82). Twenty were treated with primary radiosurgery, and 15 patients were treated with adjuvant radiosurgery after surgical resection. Patients were assessed clinically and radiologically at routine intervals following GKRS. Kaplan-Meier analysis was used to assess tumor progression.

RESULTS

The mean follow-up was 5 years (range 2-16 years). The mean pre-radiosurgery tumor volume was 5.1 cc (range 0.7-27.3cc). At last follow-up, 31 patients (89%) displayed either no growth or a decrease in tumor volume. Four (11%) patients displayed an increase in volume. Kaplan Meier analysis demonstrated radiographic progression free survival at 3, 5, and 10 years to be 96%, 91%, and 73% respectively. At the last clinical follow-up, 33 patients (94%) demonstrated no change or improvement in their neurological condition and 2 patients clinically declined (6%).

CONCLUSION

GKRS offers an acceptable rate of tumor control for tentorial meningiomas, and accomplishes this with a low incidence of new or worsening neurological deficits.

Gamma Knife surgery for arteriovenous malformations in children

OBJECT

The aim of this study was to evaluate the long-term imaging and clinical outcomes of intracranial arteriovenous malformations (AVMs) in children treated with Gamma Knife surgery (GKS).

METHODS

Between 1989 and 2007, 200 patients with AVMs who were 18 years of age or younger were treated at the University of Virginia Health System. Excluding 14 patients who had not reached 2-year follow-up, 186 patients comprised this study. Hemorrhage was the most common presenting symptom leading to the diagnosis of AVMs (71.5%). The mean nidus volume was 3.2 cm(3) at the time of GKS, and a mean prescription dose of 21.9 Gy was used.

RESULTS

After initial GKS, 49.5% of patients achieved total angiographic obliteration. Forty-one patients whose AVM nidi remained patent underwent additional GKS. The obliteration rate increased to 58.6% after a second or multiple GKS. Subtotal obliteration was achieved in 9 patients (4.8%). Forty-nine patients (26.3%) still had a patent residual nidus. In 19 patients (10.2%), obliteration was confirmed on MR imaging only. Ten patients had 17 hemorrhages during the follow-up period. The hemorrhage rate was 5.4% within 2 years after GKS and 0.8% between 2 and 5 years. Six patients developed neurological deficits along with the radiation-induced changes. Two patients developed asymptomatic meningiomas 10 and 12 years after GKS. After a mean clinical follow-up of 98 months, less than 4% of patients had difficulty attending school or developing a career.

CONCLUSIONS

Gamma Knife surgery offers a reasonable chance of obliteration of an AVM in pediatric patients. The incidence of symptomatic radiation-induced changes is relatively low; however, long-term clinical and imaging follow-up is required to identify delayed cyst formation and secondary tumors.

Trans-sodium crocetinate enhancing survival and glioma response on magnetic resonance imaging to radiation and temozolomide

Object

Glioblastoma (GB) tumors typically exhibit regions of hypoxia. Hypoxic areas within the tumor can make tumor cells less sensitive to chemotherapy and radiation therapy. Trans-sodium crocetinate (TSC) has been shown to transiently increase oxygen to hypoxic brain tumors. The authors examined whether this improvement in intratumor oxygenation translates to a therapeutic advantage when delivering standard adjuvant treatment to GBs.

Methods

The authors used C6 glioma cells to create a hypoxic GB model. The C6 glioma cells were stereotactically injected into the rat brain to create a tumor. Fifteen days later, MR imaging was used to confirm the presence of a glioma. The animals were randomly assigned to 1 of 3 groups: 1) temozolomide alone (350 mg/m2/day for 5 days); 2) temozolomide and radiation therapy (8 Gy); or 3) TSC (100 μg/kg for 5 days), temozolomide, and radiation therapy. Animals were followed through survival studies, and tumor response was assessed on serial MR images obtained at 15-day intervals during a 2-month period.

Results

Mean survival (± SEM) of the temozolomide-alone and the temozolomide/radiotherapy groups was 23.2 ± 0.9 and 29.4 ± 4.4 days, respectively. Mean survival in the TSC/temozolomide/radiotherapy group was 39.8 ± 6 days, a statistically significant improvement compared with either of the other groups (p < 0.05).

Although tumor size was statistically equivalent in all groups at the time of treatment initiation, the addition of TSC to temozolomide and radiotherapy resulted in a statistically significant reduction in the MR imaging–documented mean tumor size at 30 days after tumor implantation. The mean tumor size in the TSC/temozolomide/radiotherapy group was 18.9 ± 6.6 mm2 compared with 42.1 ± 2.7 mm2 in the temozolomide-alone group (p = 0.047) and 35.8 ± 5.1 mm2 in the temozolomide/radiation group (p = 0.004).

Conclusions

In a hypoxic GB model, TSC improves the radiological and clinical effectiveness of temozolomide and radiation therapy. Further investigation of this oxygen diffusion enhancer as a radiosensitizer for hypoxic brain tumors seems warranted.

Effect of trans sodium crocetinate on brain tumor oxygenation. Laboratory investigation

OBJECT

Glioblastoma multiforme tumors typically exhibit regions of hypoxia. Hypoxic regions within the tumor make cells less sensitive to radiosurgery and radiation therapy. Trans sodium crocetinate (TSC) has been shown to be a radiosensitizer. The goal of this research was to elucidate the underlying mechanism of TSC's radiosensitizing effect.

METHODS

A rat C6 glioma model was used. The C6 glioma cells were stereotactically injected into the rat brain to create a tumor. Two weeks later, MR imaging was used to confirm the presence of a glioma. Following demonstration on MR imaging of a brain tumor, animals were randomized into 1 of 2 groups: 1) TSC alone (100 microg/kg), or 2) saline control. Licox probes were inserted into the brain tumor and contralateral cerebral hemisphere. Tissue oxygenation measurements were recorded before and after intravenous infusion of either TSC or saline.

RESULTS

Not surprisingly, tissue oxygenation measurements revealed that the brain tumor was hypoxic relative to the contralateral cerebral hemisphere brain tissue. Two to 8 minutes after TSC was infused, tissue oxygenation measurements in the brain tumor increased above baseline by as much as 60%. After this temporary elevation following TSC infusion, tumor oxygenation measurements returned to baseline. No significant elevations in tissue oxygenation were seen on the contralateral side. Similarly, the saline vehicle was not observed to increase tissue oxygenation in either the brain tumor or the contralateral brain tissue.

CONCLUSIONS

Administration of TSC transiently improves tissue oxygenation in hypoxic gliomas. Such an effect is one potential mechanism for the radiosensitization previously observed after addition of TSC.

Evaluation of the role of Gamma Knife surgery in the treatment of craniopharyngiomas

✓ The management of craniopharyngioma involves balancing adequate reduction in tumor volume and prevention of recurrence while minimizing damage to delicate surrounding structures. Because of the lesion's proximity to the optic chiasm and its relationship to the hypothalamic–pituitary axis, morbidity rates following treatment can be high. Gamma Knife surgery (GKS) is now being considered as a viable method of providing tumor control while ensuring minimal side effects. The authors conducted a literature review of 10 studies in which GKS was used to treat craniopharyngioma; some lesions had been previously treated and some had not. The mean marginal dose ranged from 5 to 16.4 Gy (mean 12.3 Gy). Tumor control was achieved in 75% of cases overall and varied with tumor subtype (cystic, solid, mixed). Control was seen in 90% of solid, 80% of cystic, and 59% of mixed tumors. The overall morbidity rate resulting from radiosurgery was 4% and the overall mortality rate was 0.5%. These results suggest that GKS may provide a favorable benefit-to-risk profile for many patients with craniopharyngiomas.

Challenges in the epidemiological and clinical aspects of Burkitt's lymphoma in Kenya: linking evidence and experience

BACKGROUND

In a series of 1005 cases of Burkitt's lymphoma studied for epidemiological and clinical characteristics, some features remain less obvious contrary to what is commonly held about this disease.

OBJECTIVES

To use the case series to document the challenges in the epidemiological and clinical characteristics of Burkitt's lymphoma (BL) in Kenya.

DESIGN

Cross sectional study involving clinical review of case series.

SETTING

Kenyatta National Hospital and the seven provincial hospitals in Kenya during the period between 1986 and 1996.

DATA SOURCES

Systematic review of the epidemiological and clinical features of the 1005 cases enrolled in the case study and review of reference lists of retrieved articles to identify original research dealing with the epidemiological and clinical features of Burkitt's lymphoma.

DATA EXTRACTION

The investigators and research assistants screened both the case series and published information and data to yield relevant information.

CONCLUSION

The majority of Burkitt's lymphoma cases between the age group three and nine years of age coincide with the established epidemiological and clinical characteristics. The adult BL cases and some childhood cases however do not conform entirely to the established characteristics. Therefore, making the diagnosis of Burkitt's lymphoma require that; geographical, demographical, clinical features as well as any underlying infections for instance, Human Immunodeficiency Virus be taken into consideration.

Tracheoesophageal fistula and massive pneumoperitoneum after prolonged mechanical ventilation

We describe a patient who had two unusual complications of prolonged mechanical ventilation-tracheoesophageal fistula and pneumoperitoneum-with a fatal outcome. Recurrent pulmonary aspirations and massive abdominal distention in the setting of longstanding artificial ventilation should alert the physician to these possibilities.

A phase I-II trial of topotecan and gemcitabine in patients with previously treated, advanced non-small cell lung cancer (LOA-3)

The purposes of this study were to determine the maximum tolerated dose (MTD), dose-limiting toxicity (DLT), toxicity profile, and antitumor activity of topotecan (TOP) and gemcitabine (GEM) combination therapy when administered to patients with previously treated, advanced, non-small cell lung cancer. Both compounds were administered intravenously over 30 min, with TOP on days 1-5 and GEM on days 1 and 5 only. Nineteen patients were treated with 75 courses at three dose levels. The MTD was 0.75 and 400 mg/m2 for TOP and GEM, respectively, with thrombocytopenia and neutropenia as the DLTs. Partial responses were achieved in 3 of 17 patients (18%) with measurable disease. Six patients (32%) had disease stabilization for at least four courses of treatment. The median survival was 10 months from the initiation of TOP and GEM. This combination was relatively well tolerated and exhibited promising antitumor activity in patients with advanced, previously treated, non-small cell lung cancer.

A replication study of Reducing the Risk, a theory-based sexuality curriculum for adolescents

Reducing the Risk is a theory-based, sexuality education curriculum shown to influence the knowledge and behaviors of secondary students. This study determined whether the behavioral effects of the curriculum could be duplicated in a southern, rural state. In a quasiexperimental design, pretest and posttest inventories were administered to students in treatment and comparison groups to determine the influence of Reducing the Risk on sexual behaviors. Results of the 18-month study indicated students receiving the curriculum significantly delayed initiating sexual intercourse. Sexually active students in the treatment group were significantly more likely to protect themselves from STD/HIV and pregnancy than sexually active students in the comparison group. In addition, students receiving Reducing the Risk showed a significant increase in parent-child communication about sexual issues. These results reinforce previous research that found positive behavioral effects for students receiving the Reducing the Risk curriculum.

Psychosocial and pharmacologic explanations of nicotine's "gateway drug" function

Research has shown that adolescent users of tobacco are much more likely to progress to use of illicit drugs than are nonusers of tobacco. This article suggests potential psychosocial reasons for the progression based on principles of learning theory, Theory of Reasoned Action, Health Belief Model, and Cognitive Dissonance. In addition, a neuropharmacologic causal mechanism is discussed. The existence of tobacco's gateway function has important implications in the nation's efforts to reduce illicit drug use and adolescent smoking.

Letters

JOURNAL POLICY DEBATE COMPARING DRESSINGS.

Platelet serotonin levels in panic disorder

Platelet serotonin levels were examined in 18 patients with panic disorder and compared to platelet serotonin levels of eight healthy controls. There was no statistically significant difference in the platelet serotonin levels between the two groups.

Fatty acid composition of lizard tissue lipids and the effects of estradiol on serum free fatty acids

Fatty acid analyses of lipids from lizard fat bodies, carcass, and blood serum were performed by GLC. Principal fatty acids from all three tissues were palmitate (16:0), stearate (18:0), oleate (18:1), and linoleate (18:2). Administration of estradiol to vitellogenic or non-vitellogenic lizards increased serum levels of non-esterified fatty acids, but had no effect on the fat body wet weights. Lizards receiving estradiol had a higher proportion of arachidonate and a lower proportion of oleate in their serum non-esterified fatty acids.

Genetic studies in multiple myeloma. 1. Association with HLA-Cw5

Human leukocyte antigens (HLA) were identified in 22 black Americans with multiple myeloma. No significant association was observed between antigens at either the A or the B locus. At the C locus, in contrast, HLA-Cw5 was more prevalent in the patient group, four of 22 having it, compared with the control group, in which two of 138 individuals possessed it. All four patients with HLA-Cw5 were males. Those results suggest that genetic factors, perhaps in conjunction with an environmental change, may be responsible for the recent increase in incidence in myeloma in black Americans, especially in males.

A noninvasive technique for monitoring response to chemotherapy in human acute leukemia

To see whether urine enzyme activities could be used as an index in evaluating the disease status of leukemia patients, we examined the activities of four enzymes: arylsulfatases A(AS-A) and B(AS-B), alkaline phosphatase (AP), and lactate dehydrogenase (LDH). AP and LDH showed no consistent patterns. The activities of AS-A and AS-B correlated well with the patient's clinical status, increasing during progression of disease and decreasing toward normal activities during responses to therapy, as judged from bone marrow cellularity and differential. Among 23 untreated patients with a histologic diagnosis of acute leukemia we found increased activities of the urine enzymes in these proportions: AS-A in 23 patients (100%), AS-B in 22 (95.7%), AP in 7 (30.4%), and LDH in 10 (43.5%). Five patients in remission from acute leukemia had normal activities for all four enzymes. In one patient in remission for more than one year, a rise in urinary arylsulfatase activity preceded observable bone marrow relapse by 4 months. Unlike that of serum of urine lysozyme and serum copper, the determination of urine arylsulfatase activities appears to be a consistent, useful indicator of response to antileukemic therapy. In contrast to the determination of polyamines, the quantitation of arylsulfatase activity is achieved with greater ease and with instrumentation available in most clinical laboratories.

Biofeedback and rational-emotive therapy in the management of migraine headache

Twenty-four migraine patients were randomly assigned to one of four conditions: (a) self-monitoring of headache activity (waiting list), (b) frontalis EMG biofeedback, (c) digit temperature biofeedback, and (d) digit temperature biofeedback plus Rational-Emotive Therapy (RET). Bidirectional control over the target physiological response was assessed through a reversal design in each session. Following at least a four-week baseline, the three biofeedback groups received 8 to 10, 30-minute sessions of bidirectional biofeedback training, scheduled twice a week. Subjects in the combined digit temperature biofeedback plus RET group received three 40-minute sessions of RET as an addition to the third, fifth, and seventh biofeedback sessions. Records of daily home practice were kept throughout treatment and three-month followup. Subjects on the waiting list monitored headaches for at least five months, corresponding to "baseline", "treatment", and three-month followup. Digit temperature biofeedback alone and in conjunction with RET did not prove to be more effective than the control conditions. All the EMG subjects reduced headache activity to two-thirds or less of the baseline level by the third month of followup. Bidirectional digit temperature performance did not improve with training, was demonstrated in only 33% of the biofeedback sessions, was not maintained over time, and was unrelated to improvement in headache activity. EMG subjects reported biofeedback performance to be an easier task and met the performance criterion on 85% of the sessions. The frequency of home practice contributed over 55% of the variance in retrospective estimates of headache improvement but was not related to changes in daily records of headache activity.