Inhibition of cytochrome oxidase by dibucaine

[Emergency combined surgery for acute appendicitis and cystic lesions of small pelvis]

OBJECTIVE

To determine the optimal surgical approach for acute appendicitis and concomitant cystic lesions of small pelvis.

MATERIAL AND METHODS

The authors report the results of emergency combined surgery on abdominal and pelvic organs in 995 patients for the period from 1990 to 2020 (30 years). Acute appendicitis was diagnosed in 698 (70.15%) patients. Cystic lesions of small pelvis were observed in 286 (28.7%) patients: follicular cyst - 133 (46.5%), serous cyst - 91 (31.8%), corpus luteum cyst - 42 (46.4%), dermoid cyst - 20 (7.0%), endometrioid cyst - 3 (1.0%) cases. Catarrhal appendicitis was diagnosed in 10 (1.4%) patients, phlegmonous appendicitis - 685 (98.1%), gangrenous appendicitis - 3 (0.4%) patients. All patients with pyoinflammatory diseases of small pelvis had long-term history of gynecological diseases.

RESULTS

Cystic lesions of small pelvis can undergo malignant transformation. Therefore, surgical intervention is determined by surgeon together with gynecologist. Tree large endometrioid cysts (20-25 cm) were malignant. These patients also had adenocarcinoma of sigmoid colon. Malignant neoplasm resulted acute ileus, and the cysts were incorporated into pyogenic membrane. Extensive adhesive process was also observed. These aspects caused significant technical difficulties during resection of these cysts. Postoperative complications occurred in 2.31% of patients.

CONCLUSION

Prolonged therapy and follow-up of patients with urgent concomitant inflammatory diseases of abdominal cavity and small pelvis (chronic nonspecific salpingitis, diffuse pelvic endometriosis, ovarian cysts, etc.) can lead to development and growth of cystic lesions of small pelvis. These cysts may be complicated by subsequent malignant transformation.

Drug-induced mitochondrial toxicity

Mitochondria play a critical role in generating most of the cell's energy as ATP. They are also involved in other metabolic processes such as urea generation, haem synthesis and fatty acid beta-oxidation. Disruption of mitochondrial function by drugs can result in cell death by necrosis or can signal cell death by apoptosis (e.g., following cytochrome c release). Drugs that injure mitochondria usually do so by inhibiting respiratory complexes of the electron chain; inhibiting or uncoupling oxidative phosphorylation; inducing mitochondrial oxidative stress; or inhibiting DNA replication, transcription or translation. It is important to test for mitochondrial toxicity early in drug development as impairment of mitochondrial function can induce various pathological conditions that are life threatening or can increase the progression of existing mitochondrial diseases.

Mitochondrial targets of drug toxicity

Mitochondria have long been recognized as the generators of energy for the cell. Like any other power source, however, mitochondria are highly vulnerable to inhibition or uncoupling of the energy harnessing process and run a high risk for catastrophic damage to the cell. The exquisite structural and functional characteristics of mitochondria provide a number of primary targets for xenobiotic-induced bioenergetic failure. They also provide opportunities for selective delivery of drugs to the mitochondrion. In light of the large number of natural, commercial, pharmaceutical, and environmental chemicals that manifest their toxicity by interfering with mitochondrial bioenergetics, it is important to understand the underlying mechanisms. The significance is further underscored by the recent identification of bioenergetic control points for cell replication and differentiation and the realization that mitochondria play a determinant role in cell signaling and apoptotic modes of cell death.

Inhibition of protein import into mitochondria by amphiphilic cations: potential targets and mechanism of action

In this paper we describe for the first time the inhibitory effect of three amphiphilic cations, trifluoperazine, propranolol and dibucaine on mitochondrial protein import. The amphiphilic cations did not affect binding of mitochondrial precursor proteins to mitochondria. Import into mitoplasts was affected in a similar manner to intact mitochondria, indicating that the protein import machinery of the inner membrane of mitochondria was responsible for the observed effect. At concentrations which completely inhibited protein import, the amphiphilic cations did not affect the membrane potential (DeltaPsi) across the inner membrane. The inhibitory potency of amphiphilic cations reflects their lipid/water partition coefficient and relatively high concentrations of the drugs were required for complete inhibition, hence we propose that the mechanism of protein import inhibition by amphiphilic cations is due to membrane perturbing effects. We discuss the implications of our findings in view of the possible connection between various inner mitochondrial membrane channels and the protein import pore.