Morphine and MK-801 administration leads to alternative N-methyl-D-aspartate receptor 1 splicing and associated changes in reward seeking behavior and nociception on an operant orofacial assay.

The NMDA receptor plays a large role in opioid-induced plastic changes in the nervous system. The expression levels of its NR1 subunit are altered dramatically by morphine but no changes in its alternative splicing have been reported. Changes in the splicing of the N1, C1, C2, and C2' cassettes can alter the pharmacology and regulation of this receptor. Western Blots run on brain tissue from rats made tolerant to morphine revealed altered splicing of the N1 cassettes in the accumbens and amygdala (AMY), and the C1 cassette in the AMY and the dorsal hippocampus (HIPP). After 3days of withdrawal C2'-containing NR1 subunits were down-regulated in each of these areas. These were not due to acute doses of morphine and may represent long-term alterations in drug-induced neuroplasticity. We also examined the effects of morphine tolerance on an operant orofacial nociception assay which forces an animal to endure an aversive heat stimulus in order to receive a sweet milk reward. Morphine decreased pain sensitivity as expected but also increased motivational reward seeking in this task. NMDAR antagonism potentiated this reward seeking behavior suggesting that instead of attenuating tolerance, MK-801 may actually alter the rewarding and/or motivational properties of morphine. When combined, MK-801 and morphine had an additive effect which led to altered splicing in the accumbens, AMY, and the HIPP. In conclusion, NR1 splicing may play a major role in the cognitive behavioral aspects especially in motivational reward-seeking behaviors.

Intradermal injection of Botulinum toxin type A alleviates infraorbital nerve constriction-induced thermal hyperalgesia in an operant assay.

Recent studies have shown that infraorbital nerve constriction (IoNC)-induced mechanical allodynia has been attenuated by administration of highly purified 150-kDa Botulinum neurotoxin type A (BoNT/A). Here, we extend these studies to determine whether BoNT/A could attenuate IoNC-induced symptoms of thermal hyperalgesia. Instead of testing head withdrawal thresholds, a thermal operant assay was used to evaluate cortical processing of sensory input following IoNC. In this assay, a fasted rat's desire to obtain a food reward (sweetened condensed milk) is coupled to its ability to tolerate facial contact with a warm (45 °C) thermode. Bilateral IoNC decreased the ratio of thermode contact duration/event, which is an indicative of thermal hyperalgesia. BoNT/A injection intradermally in the area of infraorbital nerve (IoN) innervation 7 days after IoNC resulted in decreased number of facial contacts and increased the ratio of contact duration/event (measured at 14 days after IoNC). The BoNT/A (2-200 pg) effects were dose dependent and statistically significant at 100 and 200 pg (P < 0·05). Complete reversal of thermal hyperalgesia symptoms was obtained with a 200-pg dose, without affecting sham rat behaviour. Off-site (neck) injection of BoNT/A did not relieve thermal hyperalgesia, while co-injection of BoNT/A with a neutralising antibody in the area of IoN innervation prevented relief of thermal hyperalgesia. Neither IoNC nor BoNT/A injection affected operant assay parameters with a 24 °C thermode, indicating selectivity of thermal hyperalgesia measurements. These results strongly suggest that intradermal injection of BoNT/A in the area of IoN innervation alleviates IoNC-induced thermal hyperalgesia in an operant assay.

Recombinant human erythropoietin in a patient with multiple myeloma and end-stage renal disease.

Recombinant human erythropoietin (rHuEpo) is an established, effective treatment for the anemia of chronic renal failure. Recent reports also suggest it may be efficacious in the anemias of drug toxicity, rheumatoid arthritis, and multiple myeloma without renal failure. We describe the positive response to rHuEpo in an end-stage renal disease patient with active multiple myeloma and ongoing chemotherapy. Before rHuEpo therapy, the patient was transfusion dependent, but after rHuEpo was initiated, transfusions were not required. Multiple myeloma with renal failure does not preclude a response to rHuEpo. Further trials of rHuEpo in the treatment of multiple myeloma with and without renal failure are warranted.

Adjuvant methotrexate-5-fluorouracil for extracapsular squamous cell carcinoma in cervical metastasis.

A trial of surgery, irradiation, and adjuvant chemotherapy was offered to patients with extracapsular spread of squamous cell carcinoma in cervical metastases. Following surgery and irradiation, methotrexate, 5-fluorouracil, and leucovorin were administered 18 times over 6 months. Fifty patients undertook chemotherapy, while 47 patients declined further therapy. Comparison of the two groups according to stage, site, and Karnofsky performance status demonstrated no significant differences. The number of nodes encountered and the number and percentage of nodes with extracapsular spread were similar in the two groups. The minimum 5-year adjusted survival for patients undergoing adjuvant chemotherapy is 54% (20 of 37 patients), while survival of patients who failed to undertake adjuvant chemotherapy was 17% (5 of 30 patients). These data suggest the efficacy of methotrexate-5-fluorouracil adjuvant chemotherapy and support the need for a prospective randomized clinical trial.

Cisplatin--5-fluorouracil chemotherapy for advanced inoperable squamous carcinoma of the head and neck.

Patients with locally advanced, inoperable squamous cell carcinoma of the head and neck were offered three courses of cisplatin and 96-h 5-fluorouracil (5-FU) infusion. Subsequent therapy included surgery when feasible, irradiation therapy, and a maintenance program of methotrexate (MTX)-5-FU. Thirty-three patients were evaluated prospectively. Seven patients underwent a single course of chemotherapy. Five patients underwent two courses of chemotherapy. Twenty-one patients underwent three courses of adjuvant chemotherapy. The overall response rate was 48% (16 of 33). Fifteen of 21 patients (76%) receiving three courses of chemotherapy evidenced a response; this included three complete responses (CRs) (9%). No responses were seen in patients receiving only one or two courses of chemotherapy. Among responding patients, the initial favorable response to chemotherapy was apparent after the first course of chemotherapy. Patients who failed to demonstrate any response after two courses of chemotherapy did not respond after a third course. A significant group of patients fail to respond and should be offered participation in other investigational protocols as they become available.

Adjuvant chemotherapy for high-risk squamous-cell carcinoma of the head and neck.

A prospective clinical trial was developed to evaluate efficacy, toxicity, and patient compliance to adjuvant chemotherapy following surgery and postoperative radiation therapy in patients with squamous-cell carcinoma of the head and neck with extracapsular spread of tumor in cervical metastases. Following postoperative radiation therapy, 18 courses of methotrexate (MTX) and 5-fluorouracil (5-FU) were administered over 6 months. Fifty patients were registered. A total of 771 doses were administered. Dose reduction was required 72 times. Therapy was stopped in one patient (2%) because of toxicity. Three patients (6%) refused to complete the adjuvant therapy. Adjusted 2-year no evidence of disease (NED) survival is 66%. This study demonstrates that patients with advanced squamous-cell carcinoma of the head and neck can undertake an aggressive program of adjuvant MTX/5-FU with acceptable compliance and toxicities. Preliminary data generated in this nonrandomized study support the call for a prospective randomized multiinstitutional trial of this program.

Maintenance chemotherapy for high-risk patients. A preliminary report.

A prospectively designed program employing surgery, radiotherapy, and maintenance chemotherapy was initiated for patients with histologic evidence of extracapsular spread of tumor in cervical metastases. Postoperative radiotherapy consisted of 6,000 rad of cobalt 60 administered in 180- to 200-rad fractions. Chemotherapy was initiated two to four weeks following radiotherapy. Methotrexate sodium (250 mg/sq m), fluorouracil (600 mg/sq m), and leucovorin calcium were administered one day per week, two weeks of three, for a total of 18 treatments in six months. Thirty-two patients have been in the therapeutic program. Toxic reaction has been minimal and self-limiting. One patient stopped chemotherapy because of toxic reaction. One patient (3%) was noncompliant. All patients have been followed up for 18 to 33 months. Twenty-one patients remain alive and free of disease (81% determinate survival). This compares with a 36% (9/25) disease-free survival for concurrent controls and 39% survival for historic controls.