Modification of sexual behavior of Long-Evans male rats by drugs acting on the 5-HT1A receptor

Modulation of the sexual behavior of male rats by the anxiolytic buspirone (S-20499) and its analog gepirone were compared to the effects of 8-OH-DPAT (or DPAT, a selective 5-HT1A reference agonist), and BMY-7378 (a selective 5-HT1A partial agonist). Long-Evans rats were used; modulation of copulatory behavior and alteration of penile reflexes were examined. Modulation of copulatory behavior was assessed by three indices: frequency and length of intromission, and latency of ejaculation. DPAT, at doses of 1-8 mg/kg, reduced these three indices in a time dependent manner such that the effects peaked at 45 min and normalized at 90 min. The dose-effect relationship (assessed 45 min after DPAT injection) is bell-shaped with an ED50 approximately 1 mg/kg on the ascending limb of the curve. The effects of buspirone (2 mg/kg) and gepirone (2 mg/kg) on copulatory behavior were indistinguishable from control. BMY-7378 alone and in combination with these other 5-HT1A agonists reduced copulatory behavior, though not statistically significant. Penile reflexes, including number of erections, cups and flips, were inhibited by these agents: DPAT>buspirone>gepirone (inactive at 2 mg/kg). Furthermore, the latency period to erection was at least doubled by DPAT (2 mg/kg). Buspirone and gepirone, however, reduced the latency period to erection. BMY-7378 inhibited penile reflexes when administered alone and even more in combination with DPAT or buspirone. Two butyrophenone analogs, spiperone (a 5-HT1A and dopamine D2 antagonist) and haloperidol (a D2 antagonist), were also tested for their interaction with DPAT. Both of these drugs (at 0.25 mg/kg, 60 min after administration) reduced all indices of penile reflexes and copulation. Furthermore, in combination with DPAT (2 mg/kg, 45 min), the effects were synergistic such that sexual activity came nearly to a standstill. These opposing effects on putatively brain originated copulatory behavior and spinal mediated penile reflexes indicate that the effects of buspirone and DPAT on sexual behavior in the male rat may be possible at different parts of the central nervous system. If a tentative shared target site by DPAT and buspirone is the 5-HT1A receptor, than the same 5-HT receptor sub-type at different locations (brain, raphe nuclei, spinal cord and autonomic ganglia) may modulate rat sexual behavior in opposing ways.     

The Correlation Between the New Rigiscan Plus Software and the Final Diagnosis in the Evaluation of Erectile Dysfunction

Purpose

The computer generated recordings for 2 nights in 40 patients studied with the RigiScan^† device were reevaluated using the new RigiScan Plus software to test its value in improving the discrimination between psychogenic and organic erectile dysfunction.

Materials and Methods

Each man was evaluated for erectile dysfunction with a detailed medical and sexual history, physical examination, biothesiometry, plethysmography, 2 nights of ambulatory RigiScan monitoring and a psychological evaluation that usually included a private interview with the sexual partner. At the conclusion of evaluation each patient was broadly classified as having organic or psychogenic erectile dysfunction. The RigiScan reports were initially independently analyzed without the investigator's knowledge of the final diagnosis by determining the single best erectile event, with a minimal cutoff value of 60 percent erection for 5 minutes as necessary to be considered normal and the sum of measurements from the 2 nights. The original reading and final diagnosis were correlated. At this point the data were processed with the new RigiScan Plus software using 2 new measurements: 1) rigidity activity units and 2) tumescence activity units at the base and tip of the penis, and the results were correlated with the final diagnosis.

Results

Evaluation of the single best event again showed that tip rigidity was the best single predictor if the diagnostic criteria were modified to 70 percent tip rigidity for 5 minutes with an estimate of correct classification of 92.5 percent. Nearly the same accuracy was obtained by base single event rigidity, tip rigidity and base tumescence activity units (each 90 percent). The summary analysis of all erectile events during the 2 nights of evaluation that had a low correlation with the final diagnosis using the original software showed that the best overall predictor of final diagnosis was tip tumescence activity units (92.5 percent), followed by base rigidity and tumescence activity units (each 90 percent).

Conclusions

The RigiScan Plus software introduced 4 new parameters that facilitate interpretation of the RigiScan data. The new software did not improve the correlation with the final diagnosis compared to the subjective single best event analysis but added new objective parameters, measured and displayed by the software, that facilitate use of the data by the physician.     

T-maze learning, spontaneous activity and food intake recovery following systemic administration of the noradrenaline neurotoxin, DSP4

Following systemic administration of the noradrenaline (NA) neurotoxin, DSP4 (50 mg/kg), rats were found to be retarded in the rate at which they acquired the "right-turn" running response in a modified T-maze choice situation, as measured by the total number of errors per session and median latency to reach the goal box. Desipramine (DMI, 20 mg/kg), injected 30 min before DSP4 blocked the acquisition retardation. DSP4 was found to have a short-lasting effect upon spontaneous motor activity, while food and water intake recovery was complete within 7 days of the injection. Both the NA-accumulation data and endogenous NA concentrations indicated profound NA, but not 5-hydroxytryptamine (5-HT) and dopamine (DA), depletions in the cortex, hippocampus and cerebellum. These data seem to confirm the role of the locus coeruleus-noradrenaline (LC-NA) system in an instrumental learning situation.     

Radiotherapy with or without mitomycin c in the treatment of locally advanced head and neck cancer: results of the IAEA multicentre randomised trial.

BACKGROUND AND PURPOSE: Single agent mitomycin c (MMC) has been shown to improve the outcome of radiotherapy in single institution trials. In order to confirm these findings in a broader worldwide setting, the International Atomic Energy Agency (IAEA) initiated a multicentre trial randomising between radiotherapy alone versus radiotherapy plus MMC. MATERIAL AND METHODS: Patients with advanced head and neck cancer were treated with primary curative radiotherapy (66 Gy in 33 fractions with five fractions per week) +/-a single injection (15 mg/m(2)) of MMC at the end of the first week of radiotherapy. Stratification parameters were tumour localization, T-stage, N-stage, and institution. A total of 558 patients were recruited in the trial from February 1996 to December 1999. Insufficient accrual and reporting led to the exclusion of three centres. The final study population consisted of 478 patients from seven centres. Patients had stage III (n=223) or stage IV (n=255) squamous cell carcinoma of the oral cavity (n=230), oropharynx (n=140), hypopharynx (n=65) or larynx (n=43). Prognostic factors like age, gender, site, size, differentiation and stage were well balanced between the two arms. RESULTS: The haematological side effects of MMC were very modest (<5% grade 3-4) and did not require any specific interventions. Furthermore, MMC did not enhance the incidence or severity of acute and late radiation side effects. Confluent mucositis and dry skin desquamation was common, occurring in 56% and 62% of patients, respectively. The overall 3-year primary locoregional tumour control, disease-specific and overall survival rates were 19, 36 and 30%, respectively. Gender, haemoglobin drop, tumour site, tumour and nodal stage were significant parameters for loco-regional tumour control. There was no significant effect of MMC on locoregional control or survival, except for the 161 N0 patients, where MMC resulted in a better loco-regional control (3-year estimate 16% vs. 29%, P=0.01). CONCLUSIONS: The study did not show any major influence of MMC on loco-regional tumour control, survival or morbidity after primary radiotherapy in stage III-IV head and neck cancer except in N0 patients where loco-regional control was significantly improved.     

Multigenic control of skin tumor susceptibility in SENCARA/Pt mice

Skin tumors induced in mice by initiation-promotion (2 microg DMBA-2 microg TPA) protocols were found to be under multigenic control. Eighty- one N2 mice from the cross (BALB/cAnPt x SENCARA/Pt)F1 x SENCARA/Pt that were either solidly resistant (no papillomas) or highly susceptible (> or = 7 papillomas/mouse) were subjected to a 'genome scan' using 89 microsatellite markers to check for associations with susceptible and resistant phenotypes. A locus on Chr 5 (Skts4) was found to control the susceptibility of SENCARA/Pt mice and the resistance of BALB/cAnPt mice to papilloma formation. In addition, higher than expected linkage scores were seen for the markers D9Mit271, D11Mit268 and D12Mit56. Further work is required to establish whether genes determining papilloma formation are located in these regions of the genome. In general, no evidence was seen for loss of heterozygosity in microsatellite markers on Chrs 5, 9 and 11 in 17 microdissected papillomas from (BALB/c x SENCARA)F1 hybrid mice.      

Humeral blade plate fixation of intercalary allografts and segmentally comminuted proximal humeral fractures: a preliminary report

The AO 90° humeral blade plate is a relatively new device, whose primary indication and previously described use is for proximal humeral fracture non-union. This study describes the use of the humeral blade plate for extended indications-fixation of segmentally comminuted proximal humeral fractures in two patients and fixation of humeral intercalary allografts after primary humeral neoplasm resection in three patients. A mean follow-up of 20 months revealed union in both fractures and five of the six allograft-host junctions. One patient required subsequent bone grafting for non-union at a proximal allograft-host junction. Functional results were excellent in three patients, good in one, and fair in one. Problems encountered intraoperatively were directly related to the limited array of implants. The long plates which were needed had blades which were too long and required intra-operative trimming in three cases. In four cases, additional plates were used to supplement the blade plate for distal fixation. In conclusion, the humeral blade plate is a useful device for fixation in these extended indications, but longer plates with 30.0 and 40.0-mm blade lengths should be made available.     

Evaluation of inhibitory potential of some selective methanolic plants extracts on biological characteristics of Acanthamoeba castellanii using human corneal epithelial cells in vitro

Acanthamoeba is an opportunistic protozoan pathogen and known to be one of the most ubiquitous organisms, play a vital role in ecosystem, and recognized to cause blinding keratitis and rare but fatal granulomatous encephalitis involving the central nervous system with a very poor prognosis. This is due to limited availability of effective anti-Acanthamoeba drugs. The objective of the present study was to determine the efficacy of methanolic plants crude extracts on the viability and biological properties of Acanthamoeba castellanii (T4 genotype) and its cytotoxic effects on human corneal epithelial cells (HCEC). Using HCEC, it was observed that Acanthamoeba exhibited binding (>90 %) and cytotoxicity (>80 %) to host cells. However, plant crude extracts remarkably inhibited more than 70 and 60 % of Acanthamoeba binding and cytotoxicity to HCEC, respectively. It was further established that crude extracts (ranging from 0.1 to 1.5 mg/ml) exhibited amoebicidal effects, i.e., >50 % of trophozoites were killed/reduced at maximum dose (1.5 mg/ml) within 1 h incubation. However, the residual subpopulation remained static over longer incubations. Furthermore, growth assay demonstrated crude extracts inhibited >50 % Acanthamoeba numbers up to 7 days. Our results confirmed that plant crude extracts has inhibitory effects on Acanthamoeba growth and viability. Overall, these findings revealed that tested plant extracts is inhibitory to Acanthamoeba properties associated with pathogenesis. To the best of our knowledge, our findings demonstrated for the first time that selected methanol plant crude extracts exhibits inhibitory effects on biological properties of Acanthamoeba without any toxic effects on HCEC cells in vitro.