[Treatment and prognosis analysis of 488 patients with FIGO 2018 stage Ⅲc squamous cervical cancer]

Objective: To analyze the treatment and prognosis of patients with International Federation of Gynecology and Obstetrics (FIGO) 2018 stage Ⅲc cervical squamous cell carcinoma. Methods: A total of 488 patients at Zhejiang Cancer Hospital between May, 2013 to May, 2015 were enrolled. The clinical characteristics and prognosis were compared according to the treatment mode (surgery combined with postoperative chemoradiotherapy vs radical concurrent chemoradiotherapy). The median follow-up time was (96±12) months ( range time from 84 to 108 months). Results: (1) The data were divided into surgery combined with chemoradiotherapy group (surgery group) and concurrent chemoradiotherapy group (radiotherapy group), including 324 cases in the surgery group and 164 cases in the radiotherapy group. There were significant differences in Eastern Cooperation Oncology Group (ECOG) score, FIGO 2018 stage, large tumors (≥4 cm), total treatment time and total treatment cost between the two groups (all P<0.01). (2) Prognosis: ① for stage Ⅲc1 patients, there were 299 patients in the surgery group with 250 patients survived (83.6%). In the radiotherapy group, 74 patients survived (52.9%). The difference of survival rates between the two groups was statistically significant (P<0.001). For stage Ⅲc2 patients, there were 25 patients in surgery group with 12 patients survived (48.0%). In the radiotherapy group, there were 24 cases, 8 cases survived, the survival rate was 33.3%. There was no significant difference between the two groups (P=0.296). ② For patients with large tumors (≥4 cm) in the surgery group, there were 138 patients in the Ⅲc1 group with 112 patients survived (81.2%); in the radiotherapy group, there were 108 cases with 56 cases survived (51.9%). The difference between the two groups was statistically significant (P<0.001). Large tumors accounted for 46.2% (138/299) vs 77.1% (108/140) in the surgery group and radiotherapy group. The difference between the two groups was statistically significant (P<0.001). Further stratified analysis, a total of 46 patients with large tumors of FIGO 2009 stage Ⅱb in the radiotherapy group were extracted, and the survival rate was 67.4%, there was no significant difference compared with the surgery group (81.2%; P=0.052). ③ Of 126 patients with common iliac lymph node, 83 patients survived, with a survival rate of 65.9% (83/126). In the surgery group, 48 patients survived and 17 died, with a survival rate of 73.8%. In the radiotherapy group, 35 patients survived and 26 died, with a survival rate of 57.4%. There were no significant difference between the two groups (P=0.051). (3) Side effects: the incidence of lymphocysts and intestinal obstruction in the surgery group were higher than those in the radiotherapy group, and the incidence of ureteral obstruction and acute and chronic radiation enteritis were lower than those in the radiotherapy group, and there were statistically significant differences (all P<0.01). Conclusions: For stage Ⅲc1 patients who meet the conditions for surgery, surgery combined with postoperative adjuvant chemoradiotherapy and radical chemoradiotherapy are acceptable treatment methods regardless of pelvic lymph node metastasis (excluding common iliac lymph node metastasis), even if the maximum diameter of the tumor is ≥4 cm. For patients with common iliac lymph node metastasis and stage Ⅲc2, there is no significant difference in the survival rate between the two treatment methods. Based on the duration of treatment and economic considerations, concurrent chemoradiotherapy is recommended for the patients.

[A comparative study of breast cancer mass screening and opportunistic screening in Chinese women]

Objective: To compare the population characteristics, the positive rate of screening, the detection rate of breast cancer, early diagnosis rate and the cost between the mass screening group and opportunistic screening group of breast cancer. Methods: This study is a prospective multicenter cohort study conducted from January 1, 2014 to December 31, 2016. The participants were enrolled for mass screening or opportunistic screening of breast cancer. After completing the questionnaire, all the participants received breast physical examination and breast ultrasound examination every year for 3 rounds by year. The participants' characteristics and screening results of the two groups were compared by χ² test, Fisher exact test or Wilcoxon rank-sum test. Results: A total of 20 080 subjects were enrolled. In the mass screening group, 9 434 (100%), 8 111 (85.98%) and 3 940 (41.76%) cases completed the 3 rounds of screening, and 10 646 (100%), 6 209 (58.32%) and 2 988 (28.07%) cases in the opportunistic screening group, respectively. In the opportunistic screening group, the proportions of less than 3 months lactation (1 275/9 796 vs. 1 061/8 860, χ²=4.597, P=0.032), non-fertility (850/10 646 vs. 574/9 434, χ²=27.400, P<0.01), abortion history (6 384/10 646 vs. 5 062/9 434, χ²=81.232, P<0.01), postmenopausal (2 776/10 646 vs. 2 217/9 434, χ²=17.757, P<0.01), long-term oral contraceptives(>6 months) (171/10 646 vs. 77/9 434, χ²=25.593, P<0.01) and family history of breast cancer in first-degree relatives (464/10 646 vs. 236/9 434, χ²=51.257, P<0.01) were significantly higher than those in mass screening group. The positive rate of screening (514/10 646 vs. 128/9 434, χ²=194.736, P<0.01), the detection rate of breast cancer (158/10 646 vs. 13/9 434, χ²=107.374, P<0.01), and positive rate of biopsy (158/452 vs. 13/87, χ²=13.491, P<0.01) in the opportunistic screening group were significantly higher than those of the mass screening group. The early diagnosis rate of the mass screening group was significantly higher than the opportunistic screening group (10/12 vs. 66/141, χ²=5.902, P=0.015). The average cost for detecting each breast cancer case of the mass screening group was 215 038 CNY, which was 13.6 times of the opportunistic screening group (15 799 CNY/case). In the opportunistic screening group, the positive rate of biopsy in primary hospitals was significantly lower than that in large-volume hospitals (79/267 vs. 79/185, χ²=8.267, P=0.004), but there was no significant difference in the mass screening group (6/37 vs. 7/50, χ²=0.082, P=0.774). Conclusions: Breast cancer screening can improve early detection rate. Compared with the mass screening mode, the opportunistic screening mode has the advantages of higher proportion of high-risk factors, higher positive rate of screening, higher detection rate of breast cancer, higher positive rate of biopsy, and lower cost of screening. However, the early diagnosis rate of breast cancer of opportunistic screening is lower than that of mass screening. The positive rate of opportunistic screening in primary hospitals is lower than that of large-volume hospitals. The two screening modes have their own advantages and should be chosen according to local conditions of different regions in China.

[Clinical significance of serum squamous cell carcinoma antigen in patients with early cervical squamous cell carcinoma]

Objective: To explore the clinical significance of serum squamous cell carcinoma antigen (SCC-Ag) in early cervical squamous cell carcinoma. Methods: The clinicopathological data and follow-up information of 1435 patients with stage ⅠA2-ⅡA cervical squamous cell carcinoma were collected. The correlation between serum SCC-Ag level and clinicopathological feature and prognosis were analyzed. The best cut-off of serum SCC-Ag for predicting pelvic lymph node metastasis and survival of cervical squamous cell carcinoma patients were also identified. Results: The result of univariate analysis showed that The International Federation of Gynecology and Obstetrics (FIGO) staging, tumor size, depth of cervical stromal invasion, lymphovascular space involvement, pelvic lymph node metastasis, common iliac lymph node metastasis and para-aortic lymph node metastasis were significantly related with serum SCC-Ag level (all P<0.05). The result of multivariate logistic regression analysis showed that tumor size, depth of cervical stromal invasion, pelvic lymph node metastasis and common iliac lymph node metastasis were the independent risk factors of preoperative serum SCC-Ag>2.65 ng/ml (all P<0.001). Multivariate Cox regression analysis showed that lymphovascular space involvement, SCC-Ag>3.15 ng/ml, common iliac lymph node metastasis and tumor size >4 cm were the independent prognostic risk factors (all P<0.05). The univariate analysis showed that, the tumor size, FIGO stage, depth of cervical stromal invasion and SCC-Ag level were significantly related with the recurrence of 1 096 patients without postoperative high risk factors (all P<0.05). Multivariate logistic regression analysis showed that FIGO stage (OR=1.671) and SCC-Ag>2.65 ng/ml (OR=4.490) were the independent risk factors for recurrence (both P<0.05). The best cut off of SCC-Ag for predicting early postoperative cervical lymph node metastasis of cervical squamous cell carcinoma was 2.65 ng/ml, the sensitivity was 60.8%, the specificity was 71.8%. The best cut off of SCC-Ag for predicting prognosis of cervical squamous cell carcinoma was 3.15 ng/ml, the sensitivity was 53.5%, the specificity was 71.1%. Conclusions: Preoperative serum squamous cell carcinoma antigen is an independent prognostic risk factor of survival of patients with early cervical squamous cell carcinoma, and is significantly related with recurrence of patients without postoperative high-risk factors. It can be used as a reference factor for postoperative adjuvant radiotherapy.

[Effect of SIRT1 deficiency on function of brown adipose tissue in obese mice]

OBJECTIVE

To investigate the effect of silent mating type information regulation 2 homolog 1 (SIRT1) deficiency on function of brown adipose tissue (BAT) in high-fat diet (HFD)-induced obese mice.

METHODS

Male SIRT1 deficient heterozygous (SIRT1(+ /-)) mice and their wild-type (WT) littermates were challenged with a HFD diet for 16 weeks to induce obesity model.Energy metabolic cages were used to measure oxygen consumption and heat production, and cold tolerance test was to evaluate the adaptive thermogenic function.With brown fat collected after the diet intervention, determination techniques were adopted included HE staining for morphologic changes, immunohistochemical staining and Western blotting for uncoupling protein 1 (UCP1) expression, quantitative real-time PCR for relative content of mitochondria DNA (mtDNA).

RESULTS

Compared to WT controls, SIRT1(+ /-) mice displayed significant decreases in both oxygen consumption and heat production[(2 681±297) vs (3 017±313) ml·kg(-1)·h(-1,) (19.05±2.40) vs (21.15±2.49) kcal·kg(-1)·h(-1,) both P<0.05)], as well as an impairment in maintaining their body temperature during the cold challenge.HE staining revealed the accumulation of larger lipid droplets in BAT of SIRT1(+ /-) mice, and both immunohistochemical staining and Western blotting indicated an obvious reduction in expression of UCP1 (P<0.05). Quantitative real-time PCR showed a significant decrease in the relative mtDNA content in BAT of SIRT1(+ /-) mice (0.38±0.10 vs 1.00±0.40, P<0.05).

CONCLUSION

SIRT1 deficiency promotes BAT dysfunction, meaning that whitening in obese mice.

[The influence of patatin-like phospholipase domain-containing protein 3 on palmitic acid-induced hepatocyte apoptosis]

OBJECTIVE

To explore the influence of patatin-like phospholipase domain-containing protein 3 (PNPLA3) on palmitic acid (PA)-induced hepatocyte apoptosis and its mechanism.

METHODS

Human hepatocarcinoma cell line HepG2 cells were transfected with PNPLA3(WT)-pcDNA3.1 (PNPLA3(WT) group) and PNPLA3(I148M)-pcDNA3.1 (PNPLA3(I148M) group) plasmids respectively to overexpress wild type or mutant type PNPLA3, and cells transfected with empty vector pcDNA3.1 (NC group) were set as control group.After 24 h PA incubation, Oil red staining was used to determine lipid deposition, and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay (TUNEL) was used to measure apoptosis.Western blot was used to detect the protein level of endoplasmic reticulum (ER) stress and associated apoptosis.Enzyme-linked immunosorbent assay (ELISA) was used to test lysolecithin (LPC) levels in the cellular supernatant.

RESULTS

After 24 h PA incubation, there was no significant difference in lipid deposition among three groups.Compared to NC group, the cell apoptosis rates of PNPLA3(WT) and PNPLA3(I148M) groups were increased by 2 times and 3 times respectively.The levels of ER stress PRKR-like endoplasmic reticulum kinase (PERK) pathway associated proteins, immunoglobulin-binding protein (BIP), p-PERK, p-eIF2α, and ER stress associated apoptosis pathway proteins, CCAAT/enhancer binding homologous protein (CHOP), p53 upregulated modulator of apoptosis (PUMA), Bax, caspase-3 were higher, and were more significant in PNPLA3(I148M) group.The LPC level in the supernatant of PNPLA3(WT) and PNPLA3(I148M) groups were about 5 times and 1.5 times of NC group respectively after PA incubation.

CONCLUSION

PNPLA3 may be involved in palmitic acid-induced apoptosis mediated by hepatocyte ER stress through regulating LPC metabolism.

Prognostic factors and treatment comparison in small cell neuroendocrine cervical carcinoma

OBJECTIVE

To determine the clinicopathologic factors associated with survival in small cell neuroendocrine cervical cancer (SCNEC) patients.

MATERIALS AND METHODS

The study was approved by the ethics committee of the hospital. The records of 64 SCNEC patients from 9,474 Chinese patients with cervical cancer at the Zhejiang Cancer Hospital were reviewed. Kaplan-Meier and Cox regression methods were used for analyses.

RESULTS

Of 64 patients, 47 had Stages I-IIA, 12 had Stages IIB-IVA, and five had Stage IV-B disease. A total of 81.25% underwent surgery, 89.1% received chemotherapy, 62.5% received radiation, 34.4% received neoadjuvant chemotherapy (NACT), and 34.4% received concurrent chemoradiation (CCRT). The median follow-up for surviving patients was 35.7 months (range: 0.5-160), and 29 (50%) of the 58 patients with Stages I-III had either disease recurrence or progression. The median time to first relapse was 10.5 months (range: 0-88.2). The five-year overall survival of patients in Stages I-IIA and IIB-IVB disease was 54.4% and 9.8%, respectively (p = 0.001). Women with early-stage (Stages IIBIIA) disease had median survival rates of 94 months compared with 21.4 months in the advanced-stage (Stages IIB-IVB) group. In univariate analysis, advanced-stage (p = 0.001), without radical surgery (p = 0.002) and deep stromal invasion (DSI) (p = 0.000) were considered poor prognostic factors. In a multivariable analysis, tumor size > four cm (p = 0.048), postoperative radiation (p = 0.038) for early-stage patients and the FIGO stage (p = 0.040) of disease in the overall population remained as independent prognostic factor of survival.

CONCLUSION

The FIGO stage was found to be an independent prognostic factor of SCNEC. In addition, tumor size > four cm and DSI was associated with poor survival. Postoperative radiation for early-stage patients may not improve survival. The role of primary and postoperative NACT or CCRT is unclear. Clinical trials are needed.

Effects of quercetin nanoliposomes on C6 glioma cells through induction of type III programmed cell death

Background

Quercetin has been shown to induce apoptosis in a number of cancer cell lines, but a quercetin-loaded nanoliposomal formulation with enhanced antitumor activity in C6 glioma cells and its effect on cancer cell death has not been well studied. The aim of this study was to examine if quercetin-loaded liposomes (QUE-NL) has enhanced cytotoxic effects and if such effects involve type III programmed cell death in C6 glioma cells.

Methods

C6 glioma cells were treated with QUE-NL and assayed for cell survival, apoptosis, and necrosis. Levels of reactive oxygen species production and loss of mitochondrial membrane potential (ΔΨm) were also determined by flow cytometry assay to assess the effects of QUE-NL. ATP levels and lactate dehydrogenase activity were measured, and Western blotting was used to assay cytochrome C release and caspase expression.

Results

QUE-NL induced type III (necrotic) programmed cell death in C6 glioma cells in a dose-dependent and time-dependent manner. High concentrations of QUE-NL induced cell necrosis, which is distinct from apoptosis and autophagy, whereas liposomes administered alone induced neither significant apoptosis nor necrosis in C6 glioma cells. QUE-NL-induced ΔΨm loss and cytochrome C release had no effect on caspase activation, but decreased ATP levels and increased lactate dehydrogenase activity indicated that QUE-NL stimulated necrotic cell death.

Conclusion

C6 glioma cells treated with QUE-NL showed a cellular pattern associated with necrosis without apoptosis and was independent of caspase activity. Nonapoptotic cell death induced by high concentrations of QUE-NL for controlling caspase-independent type III programmed cell death may provide the basis for novel therapeutic approaches to overcome avoidance of apoptosis by malignant cells.

Photochemical decomposition of perfluorodecanoic acid in aqueous solution with VUV light irradiation

The photochemical decomposition of perfluorodecanoic acid (PFDeA) in water in the presence of persulfate ion (S(2)O(8)(2-)) and sulfur ion (S(2-)) was investigated under vacuum ultraviolet (VUV) light irradiation. PFDeA was decomposed under VUV light irradiation. With the addition of S(2)O(8)(2-) or S(2-), the photo-decomposition and defluorination of PFDeA were enhanced significantly. Sulfate radical anion (SO(4)(*-)) generated from photolysis of S(2)O(8)(2-) initiated PFDeA oxidation. While the S(2-) ion, acting as a *OH scavenger, enhanced the role of reduction pathway induced by aqueous electrons (e(aq)(-)). The shorter-chain perfluorocarboxylic acids (PFCAs), formed in a stepwise manner from longer-chain PFCAs, were identified as products by HPLC/MS.

Photochemical decomposition of perfluorooctanoic acid in aqueous periodate with VUV and UV light irradiation

The photochemical decomposition of perfluorooctanoic acid (PFOA) in aqueous periodate (IO(4)(-)) was investigated under two types of low-pressure mercury lamps: one emits at 254nm light (UV light) and the other emits both 254 nm and 185 nm light (VUV light). PFOA decomposed efficiently under VUV light irradiation while it decomposed poorly under UV light irradiation. The addition of IO(4)(-) significantly increased the rate of decomposition and defluorination of PFOA irradiated with UV light whereas it decreased both processes under VUV irradiation. Reactive radical (IO(3)) generated by photolysis of IO(4)(-) initiated the oxidation of PFOA in UV process. Aquated electrons (e(aq)(-)), generated from water homolysis, scavenged IO(4)(-) resulting in decrease of reactive radical species production and PFOA decomposition. The shorter-chain perfluorocarboxylic acids (PFCAs) formed in a stepwise manner from long-chain PFCAs.

Selected odor compounds in cooked soymilk as affected by soybean materials and direct steam injection

Soy odor is a major concern in the consumption of soymilk by Western consumers. The objectives of this study were to determine selected soy odor compounds as affected by soybean materials and direct steam injection and to determine if the steam-injection method affected overall cooked soy aroma of the soymilk and compared to the soymilk cooked by a traditional indirect method. Five varieties of soybeans with or without lipoxygenases were processed by direct-steam injection for up to 20 min at 100 degrees C. Eight selected odor compounds were analyzed by gas chromatography after extraction using a solid-phase micro-extraction (SPME) method. Hexanal, hexanol, 1-octen-3-ol, 1-octen-3-one, and trans-2-nonenal decreased whereas 2-pentylfuran and trans-2, trans-4-decadienal increased by boiling up to 20 min. The results showed that soybean variety was a significant factor to affect odor compositions. Direct steam injection cooked soymilk resulted in lower odor contents than a traditional indirect cooking method. The advantage of having a low odor composition in the heated soymilk products made from lipoxygenases-null soybean varieties could be attained by using normal soybean materials with direct steam injection.

An alternative restorative method for regional odontodysplasia: case report

A 5-year-old Caucasian male presented with early loss of multiple deciduous teeth. All the characteristics were consistent with the diagnosis of regional odontodysplasia (ROD). Significant initial findings included premature loss of multiple primary mandibular teeth and some malformed permanent teeth. The affected teeth showed hypoplastic enamel and dentin, short roots, and wide pulp chambers, and were localized in the mandibular dentition. Treatment objectives for this patient were to provide improved esthetics, restored chewing function, and space maintenance by the construction of a temporary prosthetic restoration. However, with limited tooth support and an unusual occlusal pattern, it is difficult to obtain satisfactory retention and esthetics with traditional prosthetic techniques. In this article we introduce an alternative method for fabricating a custom removable denture and discuss the prognosis of the malformed permanent dentition and further treatment plan.

Biogenesis of transverse tubules and triads: immunolocalization of the 1,4-dihydropyridine receptor, TS28, and the ryanodine receptor in rabbit skeletal muscle developing in situ

Our previous immunofluorescence studies support the conclusion that the temporal appearance and subcellular distribution of TS28 (a marker of transverse (T) tubules and caveolae in adult skeletal muscle [Jorgensen, A. O., W. Arnold, A. C.-Y. Shen. S. Yuan, M. Gover, and K. P. Campbell, 1990, J. Cell Biol. 110:1173-1185]), correspond very closely to those of T-tubules forming de novo in developing rabbit skeletal muscle (Yuan, S., W. Arnold, and A. O. Jorgensen, 1990, J. Cell Biol. 110:1187-1198). To extend our morphological studies of the biogenesis of T-tubules and triads, the temporal appearance and subcellular distribution of the alpha 1-subunit of the 1,4-dihydropyridine receptor (a marker of the T-tubules and caveolae) was compared to (a) that of TS28; and (b) that of the ryanodine receptor (a marker of the junctional sarcoplasmic reticulum) in rabbit skeletal muscle cells developing in situ (day 19 of gestation to 10 d newborn) by double immunofluorescence labeling. The results presented show that the temporal appearance and relative subcellular distribution of the alpha 1-subunit of the 1,4-dihydropyridine receptor (alpha 1-DHPR) are distinct from those of TS28 at the onset of the biogenesis of T-tubules. Thus, in a particular developing myotube the alpha 1-DHPR appeared before TS28 (secondary myotubes; day 19-24 of gestation). Furthermore, the alpha 1-DHPR was distributed in discrete foci at the outer zone of the cytosol, while TS28 was confined to foci and rod-like structures at the cell periphery. As development proceeded (primary myotubes; day 24 of gestation) approximately 50% of the foci were positively labeled for both TS28 and the alpha 1-DHPR, while approximately 20 and 30% of the foci were uniquely labeled for TS28 and the alpha 1-DHPR, respectively. The foci labeled for both TS28 and the alpha 1-DHPR and the foci uniquely labeled for TS28 were generally confined to the cell periphery, while the foci uniquely labeled for the alpha 1-DHPR were mostly confined to the outer zone of the cytosol. 1-2 d after birth, TS28 was distributed in a chickenwire-like network throughout the cytosol, while the alpha 1-DHPR was confined to cytosolic foci. In contrast, the temporal appearance and subcellular distribution of the alpha 1-DHPR and the ryanodine receptor were very similar, if not identical, throughout all the stages of the de novo biogenesis of T-tubules and triads examined.(ABSTRACT TRUNCATED AT 400 WORDS)

Identification of novel proteins unique to either transverse tubules (TS28) or the sarcolemma (SL50) in rabbit skeletal muscle

Novel proteins unique to either transverse tubules (TS28) or the sarcolemma (SL50) have been identified and characterized, and their in situ distribution in rabbit skeletal muscle has been determined using monoclonal antibodies. TS28, defined by mAb IXE112, was shown to have an apparent relative molecular mass of 28,000 D. Biochemical studies showed that TS28 is a minor membrane protein in isolated transverse tubular vesicles. Immunofluorescence and immunoelectron microscopical studies showed that TS28 is localized to the transverse tubules and in some subsarcolemmal vesicles possibly corresponding to the subgroup of caveolae connecting the transverse tubules with the sarcolemma. In contrast, TS28 is absent from the lateral portion of the sarcolemma. Immunofluorescence studies also showed that TS28 is more densely distributed in type II (fast) than in type I (slow) myofibers. Although TS28 and the 1,4-dihydropyridine receptor are both localized to transverse tubules and subsarcolemmal vesicles, TS28 is not a wheat germ agglutinin (WGA)-binding glycoprotein and does not appear to copurify with the 1,4-dihydropyridine receptor after detergent solubilization of transverse tubular membranes. SL50, defined by mAb IVD31, was shown to have an apparent relative molecular mass of 50,000 D. Biochemical studies showed that SL50 is not related to the 52,000-D (beta subunit) of the dihydropyridine receptor but does bind to WGA-Sepharose. Immunofluorescence labeling imaged by standard and confocal microscopy showed that SL50 is associated with the sarcolemma but apparently absent from the transverse tubules. Immunofluorescence labeling also showed that the density of SL50 in type II (fast) myofibers is indistinguishable from that of type I (slow) myofibers. The functions of TS28 and SL50 are presently unknown. However, the distinct distribution of TS28 to the transverse tubules and subsarcolemmal vesicles as determined by immunocytochemical labeling suggests that TS28 may be directly involved in excitation-contraction coupling. Our results demonstrate that, although transverse tubules are continuous with the sarcolemma, each of these membranes contain one or more unique proteins, thus supporting the idea that they each have a distinct protein composition.

Tumor-promoting phorbol esters inhibit cardiac functions and induce redistribution of protein kinase C in perfused beating rat heart

Activation of protein kinase C has been implicated in the regulation of a variety of cellular reactions. Although we, and others, have found protein kinase C and its substrate proteins to be present in both membrane and cytosolic fractions in the heart, the physiologic role of this kinase in the regulation of cardiac functions remains unknown. In the present study, we found that in isolated perfused rat heart, administration of phorbol esters 4 beta-phorbol 12,13-dibutyrate(PDBu) and 12-0-tetradecanoylphorbol 13-acetate(TPA), which are specific activators of protein kinase C, produced marked dose-dependent negative changes in inotropy and chronotropy. A dose-dependent decrease in coronary flow was also observed. The diacylglycerol analogues, 1,2-oleoylacetyl-glycerol and 1,2-dioctanoylglycerol, produced similar effects as the active phorbol esters on these isolated perfused hearts. An inactive analogue of phorbol ester, 4 alpha-phorbol, failed to produce any effect. Protein kinase C activity in both membrane and cytosolic fractions prepared from rat heart could be activated by TPA and PDBu at the same concentration range as used in the experiments with perfused hearts. Following perfusion of the hearts with PDBu, a rapid translocation of protein kinase C from cytosolic to membrane fractions was also observed. Our findings provide the first direct evidence that protein kinase C may play a potentially important role in the regulation of cardiac functions.

Alteration of glucose and insulin metabolism in congenital heart disease

Children with left-to-right shunt, with and without congestive heart failure, were found to have impaired glucose tolerance tests (GTT). In cyanotic children normal levels of glucose were found in association with abnormally high levels of insulin following oral GTT. Several possible mechanisms are proposed to explain the different glucose tolerance alterations: (1) Suppression of insulin release appeared to partially explain the low levels of insulin in congestive heart failure. This suppression may be related to the high levels of circulating norepinephrine found in these patients. (2) Excessive clearance of insulin by the lung may also be responsible for the reduced arterial insulin levels in patients with left-to-right shunt, and underclearance of insulin for the abnormally higher arterial insulin levels in patients with right-to-left shunts in whom a significant amount of venous blood has bypassed the lung. (3) Hypoxia of the pancreas and the liver in cyanotic patients and those with congestive heart failure may explain the reduction of insulin levels in the hepatic vein following i.v. glucose tolerance tests. An excess production of a glucagonlike gastrointestinal factor in cyanotic children may partially explain the abnormally high levels of insulin following oral GTT.