Three-step irradiance schedule versus two-step irradiance schedule for pain control during topical 5-aminolevulinic acid-photodynamic therapy of facial acne in Chinese patients: A prospective randomized comparative study

BACKGROUND

A two-step irradiance schedule has been found to be useful for pain control during photodynamic therapy (PDT) on nonmelanotic skin cancer and condyloma acuminatum.

OBJECTIVES

To evaluate the efficacy of a new three-step irradiance schedule derived from the psychological "peak-end rule" and two-step irradiance schedule in relieving pain during 5-aminolevulinic acid PDT (ALA-PDT) on acne.

METHODS

A total of 90 moderate to severe acne patients were enrolled in our study and randomly divided into two groups with a ratio of 1:1. They were treated by a light-emitting diode light source of 633 ± 10 nm after being incubated with 5% ALA for an hour using a two-step or three-step irradiance schedule, respectively. The total irradiance intensity was 84 J/cm² of each session and the treatment interval was 2 weeks. Pain was recorded 30 min after each PDT using a visual analog scale (VAS). Follow-up was done at baseline and 2 weeks after each treatment. The numbers of lesions were counted after the third treatment through the pictures taken before and all the side effects were recorded at each follow-up visit.

RESULTS

Eighty-seven subjects completed the total three treatments (44 cases in Group A and 43 cases in Group B). The average VAS of Group B (1.61 ± 0.67) was significantly lower than that of Group A (3.14 ± 0.67), with a difference of 1.52 ± 0.08 (p < 0.0001) between them. Both groups received a similar effective rate after the total three sessions (88.64% vs. 88.37%, p > 0.05).

CONCLUSIONS

The new three-step irradiance method could relieve pain during ALA-PDT more significantly than the two-step schedule with a similar effective rate.

Pancreatic Stenting Reduces Post-ERCP Pancreatitis and Biliary Sepsis in High-Risk Patients: A Randomized, Controlled Study

Background. Endoscopic retrograde cholangiopancreatography (ERCP) is an established treatment modality for bile duct disorders, but patients have a risk of post-ERCP pancreatitis (PEP) and biliary sepsis. Aim. To evaluate the effectiveness and safety of pancreatic stent for prophylaxis of PEP and biliary sepsis in high-risk patients with complicating common bile duct (CBD) disorders. Methods. Two hundred and six patients with complicating confirmed or suspected CBD disorders were randomly assigned to receive ERCP with pancreatic stenting (experimental group) or without stenting (control group). Primary outcome measure was frequency of PEP, and secondary outcome measures included operative time, blood loss, postoperative recovery times, and other ERCP-associated morbidities. Results. Baseline age, sex, CBD etiology, concomitant medical/surgical conditions, cannulation difficulty, and ERCP success were comparable between the two groups (all P > 0.05). Compared to the control group, the experimental group had a significantly lower frequency of PEP (7.7% versus 17.7%, P < 0.05) and positive bile microbial culture (40.4% versus 62.7%, P < 0.05). However, the two groups were similar in operative time, blood loss, postoperative recovery times, and other ERCP-associated morbidities (all P > 0.05). Conclusions. Pancreatic stenting can reduce the occurrence of PEP and biliary sepsis in high-risk patients with complicating CBD disorders but does not increase other ERCP-associated morbidities. This trial is registered with the Chinese Clinical Trial Registry (registration identifier ChiCTR-OCH-14005134).

Acute antinociceptive tolerance and asymmetric cross-tolerance between endomorphin-1 and endomorphin-2 given intracerebroventricularly in the mouse

Development of tolerance in mice pretreated intracerebroventricularly with mu-opioid receptor agonist endomorphin-1, endomorphin-2, or [D-Ala(2),N-Me-Phe(4),Gly-ol(5)]-enkephalin (DAMGO) was compared between endomorphin-1- and endomorphin-2-induced antinociception with the tail-flick test. A 2-h pretreatment with endomorphin-1 (30 nmol) produced a 3-fold shift to the right in the dose-response curve for endomorphin-1. Similarly, a 1-h pretreatment with endomorphin-2 (70 nmol) caused a 3.9-fold shift to the right for endomorphin-2. In cross-tolerance experiments, pretreatment with endomorphin-2 (70 nmol) caused a 2.3-fold shift of the dose-response curve for endomorphin-1, whereas pretreatment with endomorphin-1 (30 nmol) caused no change of the endomorphin-2 dose-response curve. Thus, mice acutely tolerant to endomorphin-1 were not cross-tolerant to endomorphin-2, although mice made tolerant to endomorphin-2 were partially cross-tolerant to endomorphin-1; an asymmetric cross-tolerance occurred. Pretreatment with DAMGO 3 h before intracerebroventricular injection of endomorphin-1, endomorphin-2, or DAMGO attenuated markedly the antinociception induced by endomorphin-1 and DAMGO but not endomorphin-2. It is proposed that two separate subtypes of mu-opioid receptors are involved in antinociceptive effects induced by endomorphin-1 and endomorphin-2. One subtype of opioid mu-receptors is stimulated by DAMGO, endomorphin-1, and endomorphin-2, and another subtype of mu-opioid receptors is stimulated solely by endomorphin-2.

Partial agonistic action of endomorphins in the mouse spinal cord

The partial agonistic properties of endogenous mu-opioid peptides endomorphin-1 and endomorphin-2 for G-protein activation were determined in the mouse spinal cord, monitoring the increases in guanosine-5'-o-(3-[35S]thio)triphosphate binding. The G-protein activation induced by endogenous opioid peptide beta-endorphin in the spinal cord was significantly, but partially, attenuated by co-incubation with endomorphin-1 or endomorphin-2. The data indicates that endomorphin-1 and endomorphin-2 are endogenous partial agonists for mu-opioid receptor in the mouse spinal cord.