[Differential diagnosis and surgical management in chondrosarcoma of the jugular foramen]

Objective: To explore the diagnosis, surgical management and outcome of jugular foramen chondrosarcoma (CSA). Methods: Fifteen patients with jugular foramen CSA hospitalized in the Department of Otorhinolaryngology Head and Neck Surgery of Chinese PLA General Hospital from December 2002 to February 2020 were retrospectively collected,of whom 2 were male and 13 were female, aging from 22 to 61 years old. The clinical symptoms and signs, imaging features, differential diagnosis, surgical approaches, function of facial nerve and cranial nerves IX to XII, and surgical outcomes were analyzed. Results: Patients with jugular foramen CSA mainly presented with facial paralysis, hearing loss, hoarseness, cough, tinnitus and local mass. Computed tomography (CT) and magnetic resonance (MR) could provide important information for diagnosis. CT showed irregular destruction on bone margin of the jugular foramen. MR demonstrated iso or hypointense on T1WI, hyperintense on T2WI and heterogeneous contrast-enhancement. Surgical approaches were chosen upon the sizes and scopes of the tumors. Inferior temporal fossa A approach was adopted in 12 cases, inferior temporal fossa B approach in 2 cases and mastoid combined parotid approach in 1 case. Five patients with facial nerve involved received great auricular nerve graft. The House Brackmann (H-B) grading scale was used to evaluate the facial nerve function. Preoperative facial nerve function ranked grade Ⅴ in 4 cases and grade Ⅵ in 1 case. Postoperative facial nerve function improved to grade Ⅲ in 2 cases and grade Ⅵ in 3 cases. Five patients presented with cranial nerves Ⅸ and Ⅹ palsies. Hoarseness and cough of 2 cases improved after operation, while the other 3 cases did not. All the patients were diagnosed CSA by histopathology and immunohistochemistry, with immunohistochemical staining showing vimentin and S-100 positive, but cytokeratin negative in tumor cells. All patients survived during 28 to 234 months' follow-up. Two patients suffered from tumor recurrence 7 years after surgery and received revision surgery. No complications such as cerebrospinal fluid leakage and intracranial infection occurred after operation. Conclusions: Jugular foramen CSA lacks characteristic symptoms or signs. Imaging is helpful to differential diagnosis. Surgery is the primary treatment of jugular foramen CSA. Patients with facial paralysis should receive surgery in time as to restore the facial nerve. Long-term follow-up is necessary after surgery in case of recurrence.

[Correlational verification of drug-induced liver injury with HLA-B*35:01 allele due to Polygonum multiflorum]

In order to verify the correlation between Polygonum multiflorum-induced liver injury and HLA-B*35 : 01 alleles, six hospitalized patients diagnosed with Polygonum multiflorum-induced liver injury (PM-DILI) were selected, and their clinicopathological data were collected. Simultaneously, blood HLA-B* 35 : 01 allele detection was performed. Among the six PM-DILI cases, 4 were male, aged 38.83 ± 10.13 years old. The types of liver injury were hepatocellular injury types in all, and the severity of liver injury in five cases was grade 3. The histological presentations were acute hepatitis and acute cholestatic hepatitis. PM-DILI cases were all HLA-B*35:01 carriers, with a carrier rate of 100%. This finding indicates that PM-DILI is significantly correlated with HLA-B*35:01 alleles. Therefore, HLA-B*35 : 01 alleles can be used as an important predictive indicator for PM-DILI.

[Effect of Echinococcus multilocularis infections on mitochondrial functions of macrophages]

OBJECTIVE

To investigate the changes of mitochondrial metabolic functions of macrophages following Echinococcus multilocularis infections, so as to provide insights into the pathogenesis of alveolar echinococcosis.

METHODS

Two groups were assigned according to different treatment methods. In the culture group, mouse leukemic monocyte macrophage RAW264.7 cells were cultured with 2 000 E. multilocularis at a ratio of 500∶1, while RAW264.7 cells in the control group were given no treatment. Then, both the culture and control groups were further divided into the 24 h and 72 h subgroups. Mitochondria were stained with MitoTracker^® Deep Red FM and the mean fluorescence intensity of macrophage mitochondria was measured with the Cytation 5 Cell Imaging Multi-Mode Reader. The mitochondrial DNA copy number was quantified using the quantitative real-time PCR (qPCR) assay, and the mitochondrial energy metabolism was monitored using the Seahorse XF assay. In addition, the mitochondrial reactive oxygen species and mitochondrial membrane potential were detected using flow cytometry.

RESULTS

The mean fluorescence intensities of macrophage mitochondria were significantly lower in the 24 h (15 341 ± 2 532 vs. 17 823 ± 3 429; t = 6.379, P < 0.01) and 72 h (18 102 ± 3 505 vs. 21 511 ± 5 144; t = 17.680, P < 0.01) culture subgroups than in the corresponding control subgroups, and lower mitochondrial DNA copy numbers were measured in the 72 h culture subgroup than in the 72 h control group [(3.23 × 10⁹ ± 1.78 × 10⁷) vs. (4.39 × 10⁹ ± 3.70 × 10⁷); t = 8.85, P < 0.001]. The oxygen consumption rates were significantly greater in the 24 h [(241.70 ± 73.13) pmol/min vs. (69.05 ± 52.30) pmol/min; t = 7.89, P < 0.01] and 48 h culture groups [(249.50 ± 42.06) pmol/min vs. (60.28 ± 40.66) pmol/min; t = 8.64, P < 0.01] than in the corresponding control groups, and a higher extracellular acidification rate was seen in the 48 h culture group than in the 48 h control group ([ 111.6 ± 17.49) mpH/min vs. (35.05 ± 7.57) mpH/min; t = 16.90, P < 0.01]. In addition, flow cytometry detected higher mean fluorescence intensity of mitochondrial reactive oxygen species (58 264 ± 10 087 vs. 4 307 ± 97; t = 12.930, P < 0.01) and lower mitochondrial membrane potential (9.833% ± 2.285% vs. 2.667% ± 0.208%; t = 6.645, P < 0.01) in the 72 h culture group than in the control group.

CONCLUSIONS

E. multilocularis infection may impair mitochondrial functions and inhibit oxidative phosphorylation of macrophages, resulting in increased macrophage glycolysis. It is speculated that the alteration of macrophage metabolic states may contribute to the mechanisms underlying the development and progression of alveolar echinococcosis.

[Clinical features of patients with head and neck malignant tumor concurrent with multiple primary carcinoma]

OBJECTIVE

To analyze the clinical characteristics of multiple primary cancers (MPC) associated with head and neck.

METHODS

A total of 71 patients with MPC associated with head and neck treated from January 2008 to November 2015 were included in the retrospective study, of them 20 patients were synchronous MPC and 51 patients were metachronous MPC; 45 (63.4%) patients were field cancerization of head neck (FCHN) and 26 (36.6%) patients were non-field cancerization of head neck (NFCHN). For the synchronous MPC patients with an interval of 0 month, the lesion sites of FCHN were treated with combined chemotherapy and radiotherapy, the site of severe lesion of NFCHN received firstly a standard treatment. Other types of MPC were treated according to international guide lines or experts consensus.

RESULTS

With the mean follow-up of 63.4 months, the 3-year and 5-year overall survival (OS) were 84.6% and 75.7% respectively. The 3-year and 5-year OS were 56.4% and 37.6% respectively in patients with synchronous MPC, and were 92.2% and 84.2% respectively in patients with metachronous MPC. There was significant difference in the OS between patients with metachronous MPC and patients with synchronous MPC (P=0.0002). The 3-year and 5-year OS were 85.7% and 77.9% respectively in patients with FCHN, and were 82.9% and 72.8% respectively in patients with NFCHN, with no significant difference between the two groups (P=0.297).

CONCLUSION

With correct diagnosis and effective curative treatment, some of patients with MPC can get long-term survival, showing the better prognosis in metachronous MPC compared to synchronous MPC.

New Ir Bis-Carbonyl Precursor for Water Oxidation Catalysis

This paper introduces Ir(I)(CO)2(pyalc) (pyalc = (2-pyridyl)-2-propanoate) as an atom-efficient precursor for Ir-based homogeneous oxidation catalysis. This compound was chosen to simplify analysis of the water oxidation catalyst species formed by the previously reported Cp*Ir(III)(pyalc)OH water oxidation precatalyst. Here, we present a comparative study on the chemical and catalytic properties of these two precursors. Previous studies show that oxidative activation of Cp*Ir-based precursors with NaIO4 results in formation of a blue Ir(IV) species. This activation is concomitant with the loss of the placeholder Cp* ligand which oxidatively degrades to form acetic acid, iodate, and other obligatory byproducts. The activation process requires substantial amounts of primary oxidant, and the degradation products complicate analysis of the resulting Ir(IV) species. The species formed from oxidation of the Ir(CO)2(pyalc) precursor, on the other hand, lacks these degradation products (the CO ligands are easily lost upon oxidation) which allows for more detailed examination of the resulting Ir(pyalc) active species both catalytically and spectroscopically, although complete structural analysis is still elusive. Once Ir(CO)2(pyalc) is activated, the system requires acetic acid or acetate to prevent the formation of nanoparticles. Investigation of the activated bis-carbonyl complex also suggests several Ir(pyalc) isomers may exist in solution. By (1)H NMR, activated Ir(CO)2(pyalc) has fewer isomers than activated Cp*Ir complexes, allowing for advanced characterization. Future research in this direction is expected to contribute to a better structural understanding of the active species. A diol crystallization agent was needed for the structure determination of 3.

Iridium-based complexes for water oxidation

Activation of organometallic Ir precatalysts can yield either homogeneous or heterogeneous water-oxidation catalysts with very high activity.

Probing the Viability of Oxo-Coupling Pathways in Iridium-Catalyzed Oxygen Evolution

A series of Cp*IrIII dimers have been synthesized to elucidate the mechanistic viability of radical oxo-coupling pathways in iridium-catalyzed O2 evolution. The oxidative stability of the precursors toward nanoparticle formation and their oxygen evolution activity have been investigated and compared to suitable monomeric analogues. We found that precursors bearing monodentate NHC ligands degraded to form nanoparticles (NPs), and accordingly their O2 evolution rates were not significantly influenced by their nuclearity or distance between the two metals in the dimeric precursors. A doubly chelating bis-pyridine-pyrazolide ligand provided an oxidation-resistant ligand framework that allowed a more meaningful comparison of catalytic performance of dimers with their corresponding monomers. With sodium periodate (NaIO4) as the oxidant, the dimers provided significantly lower O2 evolution rates per [Ir] than the monomer, suggesting a negative interaction instead of cooperativity in the catalytic cycle. Electrochemical analysis of the dimers further substantiates the notion that no radical oxyl-coupling pathways are accessible. We thus conclude that the alternative path, nucleophilic attack of water on high-valent Ir-oxo species, may be the preferred mechanistic pathway of water oxidation with these catalysts, and bimolecular oxo-coupling is not a valid mechanistic alternative as in the related ruthenium chemistry, at least in the present system.

Effects of cervical spinal cord stimulation on cerebral blood flow in the rat

OBJECT

Spinal cord stimulation (SCS) is frequently used for the treatment of chronic pain. Although the mechanisms by which SCS alleviates pain are unclear, they are believed to involve changes within the dorsal horn of the spinal cord. Spinal cord stimulation has also been found to cause significant vasodilation in the peripheral vasculature. The mechanisms underlying this effect are thought to involve sympathetic blockade. A rostral vasodilatory effect has also been described, but changes in cerebral blood flow (CBF) have been poorly delineated. Using laser Doppler flowmetry (LDF), the authors examined the effects of cervical SCS on CBF in rats.

METHODS

Cervical SCS was found to result in a significant increase in cortical LDF values (83 +/- 11% [mean +/- standard error of the mean]). The increase in cortical LDF values was not accompanied by a significant increase in systemic blood pressure. Stimulation of the upper cervical spinal cord was more effective in inducing LDF changes than was that of the lower cervical cord. Changes in SDS-induced LDF values were significantly attenuated after spinal cord transection at the cervicomedullary junction and by the administration of the sympathetic blocker hexamethonium.

CONCLUSIONS

These results indicate that cervical SCS may induce cerebral vasodilation and that this effect may involve indirect effects on vasomotor centers in the brainstem as well as an alteration in sympathetic tone.

Renal squamous cell carcinoma: CT findings and clinical significance

BACKGROUND

To study the biological behavior of renal squamous cell carcinoma (RSCC).

METHODS

Fifteen cases of RSCC were retrospectively studied. These cases were classified as central (eight cases) and peripheral (seven cases) types by the tumor location. The clinical data and computed tomographic findings were analyzed and compared.

RESULTS

High incidence (87%) of urolithiasis was observed. The prognosis of RSCC was very poor, with a median survival time of 3.5 months. The infectious symptoms, central location, and modified stage IV of the tumor were the poor prognostic factors of RSCC. Two types of RSCC were different in the presenting symptoms, lymph node metastasis, modified tumor staging, and survival time.

CONCLUSION

The central and peripheral types of RSCC were different biologically. High index of suspicion should be maintained when identifying the subtle clues of malignancy in patients with urolithiasis.

Induction of hypercontractility in human cerebral arteries by rewarming following hypothermia: a possible role for tyrosine kinase

Induction of hypothermia is used routinely in neurosurgical and cardiovascular operations to protect the brain from ischemic insult. However, despite a plethora of experimental evidence supporting the use of hypothermia to protect the brain from ischemia, clinical experience using deliberate hypothermia in humans has not shown a convincing benefit. The authors tested the hypothesis that hypothermia and rewarming alter tone in human cerebral vessels and may interfere with cerebral perfusion in the setting of deliberate hypothermia. They examined human cerebral arteries during hypothermia (32 degrees C and 17 degrees C) and during rewarming to delineate the direct effects of cooling and rewarming on cerebrovascular tone. Artery segments obtained from autopsy material and from specimens excised at elective temporal lobectomies were tested in tissue baths using isometric tension measurements. Temperature-induced changes in vascular tone were measured and quantified with respect to contractile responses to serotonin (5-HT; 10(-6) M). Cooling induced mild relaxation in cerebral vessels (-38 +/- 12% 5-HT response in 50 vessels from autopsy specimens, -69 +/- 10% 5-HT response in 51 vessels from lobectomy specimens). On rewarming, vessels contracted significantly beyond their baseline tone (108 +/- 18% 5-HT response in 50 vessels from autopsy specimens, 42 +/- 12% 5-HT response in 51 vessels from lobectomy specimens). Rewarming-induced hypercontractility was inhibited by the tyrosine kinase inhibitor genistein (-5 +/- 7% vs. 70 +/- 23% 5-HT response, genistein vs. control, 14 segments, p < 0.05) and enhanced by the tyrosine phosphatase inhibitor sodium orthovanadate (339 +/- 54% vs. 104 +/- 20% 5-HT response, sodium orthovanadate vs. control, five segments, p < 0.05), indicating a possible role for tyrosine kinase activation in the rewarming-induced contraction.

Sonography and computed tomography of a gossypiboma and in vitro studies of sponges by ultrasound. Case report

A case of retained surgical sponge was imaged by ultrasound and computed tomography (CT). Sonography revealed a hypoechoic mass with areas of high echoes and acoustic shadowing. An experiment revealed that the high echoes were attributed partly to the presence of numerous interfaces of sponges. The sonographic detection of a mass with high echoes casting acoustic shadows should alert radiologists to the possibility of retained surgical sponges even if there is no gas or calcification on CT scans.

Effects of metal ions, including Mg2+ and lanthanides, on the cleavage of ribonucleotides and RNA model compounds

The cyclization/cleavage of 3',5'-uridyluridine to form 2',3'-cyclic uridylic acid is very effectively catalyzed by Eu3+, and the cyclization/cleavage of the 1-p-nitrophenyl phosphate ester of propane-1,2-diol also shows strong metal ion catalysis by Eu3+, Tb3+, and Yb3+. It also shows moderate catalysis by Mg2+, but not by Ca2+; Zn2+ and Pb2+ are also good catalysts. Various ligands activate these reactions further, and imidazole apparently acts as an additional base catalyst. Some cyclodextrin derivatives act to bind both the substrate and the metal ion but, contrary to what is reported elsewhere, there is no strong selectivity among nucleotides that can be ascribed to cyclodextrin binding.

On the mechanism of action of ribonucleases: dinucleotide cleavage catalyzed by imidazole and Zn2+

Cyclization/cleavage of the 2-(p-nitrophenyl) phosphate ester of propylene glycol is catalyzed by imidazole and, much more effectively, by Zn2+ with imidazole. In the latter case, the mechanism involves simultaneous Lewis acid/base catalysis. Similar Zn2+ and imidazole catalysis of cyclization/cleavage is seen with the dinucleotide 3',5'-UpU (uridylyluridine). Again, the zinc system is much more effective than is catalysis by imidazole alone, and in this case simultaneous Lewis acid/base catalysis substitutes for the sequential proton acid/base catalysis seen with polynucleotides or dinucleotides and imidazole buffer catalysts. A mechanism is proposed for catalysis of RNA cleavage by the enzyme ribonuclease A, and the relationship of that mechanism to the action of the enzyme model systems is discussed.