[Application of suspensory external fixation technique in treatment of proximal humeral fracture]

Objective

To investigate the effectiveness of suspensory external fixation technique in treatment of proximal humeral fractures.

Methods

Between August 2013 and October 2018, 14 patients with proximal humeral fractures were treated with suspensory external fixation technique. There were 10 males and 4 females with an average age of 55.9 years (range, 43-76 years). There were 10 cases of falling injury and 4 cases of traffic accident injury. Among them, there were 9 cases of Neer type Ⅲ and 5 cases of Neer type Ⅳ. The time from injury to operation was 3-7 days (mean, 4.6 days). Nine cases were complicated with osteoporosis. The preoperative visual analogue scale (VAS) score was 6.1±1.2. The effectiveness was comprehensively evaluated by hospital stay, fracture healing time, removal time of external fixator, postoperative complications, VAS score, and Neer score of shoulder joint function.

Results

All operations were successfully completed, and the hospital stay was 6-14 days, with an average of 9.4 days. All the incisions healed by first intention, and no infection or other complications occurred. All patients were followed up 16-60 months (mean, 35.4 months). X-ray films examination showed that all fractures healed, the healing time was 4-7 months (mean, 4.9 months). The removal time of external fixator was 5-8 months (mean, 6.3 months). VAS scores were 1.5±0.8 at 1 month after operation and 1.0±0.9 at last follow-up, both of which were significantly improved when compared with preoperative score, the differences were significant between different time points ( P<0.05). Neer score of shoulder joint function was 75-100 (mean, 91.1); 9 cases were excellent, 4 cases were good, and 1 case was fair. The excellent and good rate was 92.9%. During follow-up, there was no adverse events such as acromion impingement, nonunion, or pseudoarthrosis.

Conclusion

For proximal humeral fractures, the suspensory external fixation technique is a simple and reliable treatment method that can significantly improve joint function.

[Clinical application of nose ring drain technique combined with Ilizarov circular external fixation for Gustilo ⅢA Pilon fractures]

Objective

To investigate the effectiveness of the nose ring drain (NRD) technique combined with Ilizarov circular external fixation in treatment of Gustilo ⅢA Pilon fracture.

Methods

Between March 2017 and December 2019, 17 patients with Gustilo ⅢA Pilon fractures were admitted and treated with NRD technique combined with Ilizarov circular external fixation. Among them, there were 11 males and 6 females; the age ranged from 24 to 63 years, with an average of 38.2 years. There were 3 cases of traffic accident injury, 13 cases of falling injury, and 1 case of penetrating injury. There were 13 cases of emergency admittance and 4 cases of wound infection after surgical treatment. Furthermore, there were 2 cases of fibula fractures and 3 cases of lateral malleolus fractures.

Results

All patients were followed up 8-12 months, with an average of 9.9 months. All wounds healed by first intention, and 4 patients with preoperative infection had no recurrence during the follow-up. The external fixator was removed after fracture healing in 17 patients at 3-7 months after operation (mean, 4.5 months). At last follow-up, the pain score of the ankle joint Kofoe score was 40-50, with an average of 44; the functional score was 17-27, with an average of 25; the mobility score was 8-18, with an average of 14; and the effectiveness was rated as excellent in 8 cases, good in 7 cases, and poor in 1 case.

Conclusion

For Gustilo ⅢA Pilon fractures, the NRD technique combined with Ilizarov circular external fixation has advantages of good fracture fixation and drainage effects, which greatly reduces the complications of traditional treatment options and the number of operations.

[Epidemic situation of malaria in Yunnan Province from 2014 to 2019]

OBJECTIVE

To investigate the epidemiological characteristics of malaria and implementation of the "1-3-7" approach in malaria elimination in Yunnan Province, so as to provide the data support for the development of post-elimination surveillance interventions.

METHODS

All data pertaining to malaria cases in Yunnan Province from 2014 to 2019 were captured from the Notifiable Disease Reporting System of Chinese Center for Disease Control and Prevention, and the changes in the epidemic situation of malaria were analyzed during the 5-year period. In addition, the core indexes regarding the "1-3-7" approach in malaria elimination of Yunnan Province from 2014 to 2019 were retrieved from the Malaria Control System in the Parasitic Disease Information Reporting System, and all changes in the indexes were descriptively analyzed.

RESULTS

During the period from 2014 to 2019, a total of 2 283 malaria cases were reported in Yunnan Province, including 1 927 cases with vivax malaria, 326 cases with plasmodium malaria, 29 cases with other species of malaria, and one case with unidentified species. There were 64 local cases, 2 219 overseas imported cases. Among the 2 283 malaria cases, the male/female ratio was 4.58∶1, and 80.25% of the cases were aged from 15 to 50 years. Farmer (70.00%) was the predominant occupation, and 76.70% (1 751/2 283) of the cases were identified in 25 border counties (districts). Malaria cases were reported in each month during the 5-year period, and the number of malaria cases increased from April, peaked on May to July, and started to decline on August. From 2014 to 2019, the reporting rate of malaria cases within 24 hours upon diagnosis was 100%, and the detection of malaria cases was 99.69% (2 276/ 2 283) in the laboratory, with a 99.65% (2 275/2 283) rate of definite diagnosis. In addition, the percentage of individual epidemiological investigations within 3 days was 100.00% (2 283/2 283), and the number of epidemic foci survey and treatment within 7 days was 576 during the 3-year period from 2017 to 2019. The goal of malaria elimination was achieved in Yunnan Province on June, 2020.

CONCLUSIONS

Malaria has been eliminated in Yunnan Province, and management of overseas imported malaria is the primary challenge to consolidate the malaria elimination achievements in the future. However, the approach in malaria elimination remains to be maintained, and the role of the Yunnan Provincial Malaria Diagnostic Reference Laboratory requires to be strengthened.

Research Progress on MicroRNA in Forensic Medicine as Molecular Markers

Abstract

MicroRNA （miRNA） belongs to a class of endogenous non-coding small RNA molecules with a length of 18-24 nucleotides. The expression of miRNA is highly conservative, has time sequence and is highly tissue-specific. MiRNA could not be easily degraded by ribonuclease, and is resistant to changes in environmental factors such as temperature and pH value. Moreover, miRNA can even be detected in corrupt tissue. As a result, miRNA has broad application prospects in many fields of forensic medicine such as source identification of body fluid and estimation of cause of death. This article briefly summarizes the application of miRNA in forensic practice, such as body fluid identification, determination of postmortem interval and cause of death analysis.

[Primarily application of Ilizarov microcirculation reconstruction technique for chronic wounds in post-traumatic ischemia limbs]

Objective

To evaluate the treatment results of Ilizarov microcirculation reconstruction technique for chronic wounds in the post-traumatic ischemia limbs.

Methods

Between January 2016 and July 2019, 7 cases of chronic wounds in the post-traumatic ischemia limbs were treated. There were 5 males and 2 females, with an average age of 42.4 years (range, 29-66 years). The duration of the wound ranged from 1 month to 2 years (mean, 7.7 months). The wounds located in the leg (3 cases) or in the foot and ankle (4 cases). The wound sizes ranged from 4.0 cm×2.2 cm to 12.0 cm×7.1 cm. There were 1 case of tibial varus, 3 cases of equinovarus, 1 case of scleroderma, and 2 cases of Volkmann's ischemic contracture. After debridement, external fixators were used for tibial transverse transport, or correction of tibial varus and correction of equinovarus.

Results

All patients were followed up 8-20 months, with an average of 13 months. The infection of wound surface was all controlled in 7 cases and the granulation tissue grew well; the wound surface healed directly in 5 cases and healed after skin grafting in 2 cases, and the wound healing time was 1-3 months (mean, 1.7 months). During the follow-up, there was no recurrence of the wound. Six cases of limb deformity were corrected.

Conclusion

For the chronic wounds in the post-traumatic ischemia limbs, Ilizarov microcirculation reconstruction technique can effectively improve local circulation and facilitate the fresh granule growth and wound healing.

[Application of self-made chronic wound closure device in the repair of scarred lower extremity wounds]

Objective

To investigate the effectiveness of self-made limb chronic wound closure device in the treatment of scarred lower limbs and complex skin and soft tissue defects.

Methods

Between January 2014 and January 2017, 29 patients with complex fractures of the lower extremities and skin and soft tissue defects were treated. There were 19 males and 10 females with an average age of 31.1 years (range, 21-66 years). The causes of injury included 14 cases of traffic accidents, 5 cases of falling from height, 4 cases of heavy object crushing injury, 4 cases of mechanical crushing injury, and 2 cases of exposed steel plate after fracture. There were 26 cases of calf fracture and skin defect, 3 cases of metatarsal bone fracture and skin defect of the foot. The skin defect ranged from 5 cm×3 cm to 18 cm×8 cm. The time from injury to admission was 5-31 days, with an average of 14.3 days. All patients underwent a thorough debridement, open wound drainage, self-made chronic wound closure device combined with Ilizarov stretching technique for a slow skin and soft tissue traction. After the wound was cleaned up and the granulation tissue was freshened, the skins on both sides were closed, and then proceed to the second stage operation of skin grafting or direct suture closure based on the size of the wound.

Results

All patients were followed up 8-20 months, with an average of 13 months. Twenty-nine patients were treated with self-made chronic wound closure device combined with Ilizarov technique for 1-2 times with an average of 1.3 times, then the wound infection was controlled and the granulation tissue grew well. In the course of treatment, the pain was not obvious and the patients had good compliance. All patients' wounds healed clinically without skin traction complications and formed linear or flaky scars.

Conclusion

The self-made chronic wound closure device is effective in repairing complex scarred wounds of lower extremities, and it is easy to operate.

[A technique analysis for dissection of anterolateral thigh perforator flap]

Objective

To improve the harvesting techniques of anterolateral thigh perforator flap, and to reduce the operation time.

Methods

Between January 2008 and June 2015, 400 patients undergoing repair with anterolateral thigh perforator flap were included to analyze the technical factors, including 370 cases (92.5%) obtaining primary healing and 30 cases (7.5%) receiving re-exploration. Combined with the literature, a modified flap dissection was made: reverse tracing and sequential dissection of the descending branch of the lateral circumflex femoral artery. Between June 2015 and June 2016, the modified free anterolateral thigh perforator flap was used in 100 cases. Of 100 cases, 76 were male and 24 were female, aged from 11 to 71 years (mean, 35.6 years). The wound size ranged from 8 cm×5 cm to 23 cm×9 cm. The time between injury and surgery ranged from 5 to 31 days (mean, 14.3 days).

Results

The operation time of modified flap dissection was reduced to (30.1±19.3) minutes from (85.0±30.2) minutes (unmodified flap dissection). Postoperatively, 94 flaps survived uneventfully, and incision healed by first intention. Six flaps received re-exploration surgery because of vascular compromise; the flap survived after removal of thrombosis in 4 cases of vein thrombosis; the flap necrosed in 2 cases of vein and artery thrombosis, and skin grafting was performed. Ninety-four patients whose flaps survived were followed up 3-12 months (mean, 6.3 months); the flaps had good color and appearance, and second stage operation was performed to make the flap thinner in 21 cases.

Conclusion

Improved harvesting technique of free anterolageral thigh perforator flap could decrease surgery time and difficulty in dissection.

A novel homozygous mutation in the solute carrier family 12 member 3 gene in a Chinese family with Gitelman syndrome

Loss of function of mutated solute carrier family 12 member 3 (SLC12A3) gene is the most frequent etiology for Gitelman syndrome (GS), which is mainly manifested by hypokalemia, hypomagnesemia and hypocalciuria. We report the genetic characteristics of one suspicious Chinese GS pedigree by gene sequencing. Complete sequencing analysis of the SLC12A3 gene revealed that both the proband and his elder sister had a novel homozygous SLC12A3 mutation: c.2099T>C and p.Leu700Pro. Moreover, the SLC12A3 genes of his mother and daughter encoded the same mutated heterozygote. It was noted that in this pedigree, only the proband complained about recurrent episodes of bilateral lower limb weakness over 8 years, while his elder sister, mother and daughter did not present symptoms. The inconsistent clinical features of this pedigree implied that besides diverse phenotypes possibly originated from the same genotype, gender difference may also dominate the variant GS phenotypes. Further genetic and proteomic research are needed to investigate the precise mechanisms of GS, including the study of specific ethnicities.

A novel SLC12A3 gene homozygous mutation of Gitelman syndrome in an Asian pedigree and literature review

OBJECTIVES

Gitelman syndrome (GS) is an autosomal recessive disease characterized by hypokalemic metabolic alkalosis in combination with significant hypomagnesemia and hypocalciuria which is caused by mutations in the SLC12A3 gene. In this study, we reported a case of GS pedigree and reviewed pertinent literature so as to explore the relationship between clinical characteristics and genotype meanwhile provide recommendations for the diagnosis and treatment of GS.

DESIGN AND METHODS

This is a pedigree-based genetic study of GS and 11 members from one family were included. We summarized their clinical features, analyzed laboratory parameters related to GS and SLC12A3 gene.

RESULTS

The proband experienced intermittent severe symptoms of weakness accompanied by significant hypokalemia, hypomagnesemia and hypocalciuria in laboratory test with poor treatments. His mother had more slight symptoms of weakness than him with mild hypokalemia and hypocalciuria. Mild hypomagnesemia was also observed in his sister with occasional weakness. All other pedigree members had normal laboratory test with no GS-related symptoms. A homozygous mutation of SLC12A3 gene (c.488C > T) was detected by genetic testing in three members, and six were carriers of this mutation.

CONCLUSIONS

Genotype and phenotype vary significantly among GS patients. Male patients tend to experience more severe symptoms and poor treatment effect. Further large-scale population, animal, and molecular biology experiments are required to investigate the complexity of GS and to find a better treatment regimen for this disease.

The MTMR9 rs2293855 polymorphism is associated with glucose tolerance, insulin secretion, insulin sensitivity and increased risk of prediabetes

BACKGROUND

Polymorphism of rs2293855 in gene MTMR9 has been associated with obesity and metabolic syndrome. We aim to study the association of rs2293855 with type 2 diabetes mellitus (T2DM) intermediate phenotypes in a Han Chinese population.

METHODS

The polymorphism was genotyped in 838 Han Chinese individuals using Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS); all participants underwent a 75 g oral glucose tolerance test (OGTT); associations between the polymorphism and glucose tolerance, indices of insulin secretion and indices of insulin sensitivity were analyzed.

RESULTS

The frequency of genotypes and alleles differed significantly between normal glucose tolerance and prediabetes (P=0.043 and P=0.009, respectively). The GG homozygous presented higher fasting plasma glucose (P=0.009), higher 2-hour plasma glucose (P=0.024) and higher glucose area under the curve (AUC, P=0.01). Moreover, the G allele of rs2293855 was associated with glucose intolerance (fasting glucose, P=0.012; glucose AUC, P=0.006; 2-h glucose, P=0.024); it is also associated with decreased indices of insulin sensitivity (fasting insulin, P=0.043; insulin sensitivity index composite, P=0.009; homeostasis model assessment of insulin resistance, HOMA-IR, P=0.008) and decreased indices of insulin secretion (HOMA of beta cell function, HOMA-B, P=0.028; insulinogenic index, P=0.003). In addition, the minor allele G was also associated with increased risk of prediabetes (OR=1.463, 95%CI: 1.066-2.009, P=0.018).

CONCLUSIONS

Polymorphism of rs2293855 in MTMR9 is associated with measures of glucose tolerance, indices of insulin secretion and indices of insulin sensitivity. We also suggest that allele G is likely to increase the risk of prediabetes by influencing both insulin secretion and insulin sensitivity.

[Insulin-like growth factor 1 induces bone mesenchymal stem cells differentiation into cardiomyocyte-like cells]

OBJECTIVE

To explore the ability and mechanism of insulin-like growth factor 1 (IGF-1) induced bone mesenchymal stem cells (BMSCs) differentiation into cardiomyocyte-like cells (CLCs).

METHODS

BMSCs were isolated and purified in vitro. BMSCs were treated with control medium and 15 ng/ml IGF-1 for 3, 7, 14 and 21 d, respectively. The expression of Troponin-T (TNT), Troponin-I (TNI) and pIGF-1R were detected by immunocytochemistry and Western blot. In another experimental setting, BMSCs were treated with control medium and 15 ng/ml IGF-1, IGF-1 antagonist I-OMe AG538 (300 nmol/L) and 300 nmol/L I-OMe AG538 + 15 ng/ml IGF-1 for 3 to 48 h, respectively. Phosphorylation status of ERK1/2 and AKT, the two downstream mediators of mitogen-activated protein kinase (MAPK) kinase and phosphatidylinositol 3-kinase (PI3K) pathways, were detected by immunocytochemistry and Western blot.

RESULTS

After 3 to 21 d exposure to IGF-1, the expression of pIGF-1R, TNT and TNI were significantly higher in IGF-1 group than those in control group, pIGF-1R peaked 14 d (all P < 0.05). After 3 and 6 h treatment, the ratio of pAKT/AKT (0.17 ± 0.03) and pERK1/2/ERK1/2 (0.06 ± 0.03) were significantly downregulated in I-OMe AG538 group compared to control group (1.00 ± 0.05) (all P < 0.05). The ratio of pAKT/AKT (1.00 ± 0.07) and pERK1/2/ERK1/2 (1.00 ± 0.09) were significantly upregulated in IGF-1 group compared to control group (0.72 ± 0.05) (all P < 0.05), but the ratio of pAKT/AKT (0.31 ± 0.10) and pERK1/2/ERK1/2 (0.39 ± 0.04) were significantly downregulated in I-OMe AG538 group compared to control group (0.63 ± 0.05) (all P < 0.05), the value of gray scale of TNT (195.06 ± 5.98) and TNI (198.32 ± 3.46) in I-OMe AG538 + IGF-1 group were significantly upregulated than that in IGF-1 group for TNT (188.70 ± 5.35) and TNI (176.10 ± 4.96) (all P < 0.05).

CONCLUSIONS

IGF-1 could induce BMSCs differentiation into CLCs in vitro by activating MAPK and PI3K signaling pathways.

Inhibition of MLK3-MKK4/7-JNK1/2 pathway by Akt1 in exogenous estrogen-induced neuroprotection against transient global cerebral ischemia by a non-genomic mechanism in male rats

Numerous studies have demonstrated the neuroprotective effects of estrogen in experimental cerebral ischemia. To investigate molecular mechanisms of estrogen neuroprotection in global ischemia, immunoblotting, immunohistochemistry and Nissel-staining analysis were used. Our results showed that chronic pretreatment with beta-estradiol 3-benzoate (E2) enhanced Akt1 activation and reduced the activation of mixed-lineage kinase 3 (MLK3), mitogen-activated protein kinase kinase 4/7 (MKK4/7), and c-Jun N-terminal kinase 1/2 (JNK1/2) in the hippocampal CA1 subfield during reperfusion after 15 min of global ischemia. In addition, E2 reduced downstream JNK nuclear and non-nuclear components, c-Jun and Bcl-2 phosphorylation and Fas ligand protein expression induced by ischemia/reperfusion. Administration of phosphoinositide 3-kinase (PI3K) inhibitor LY 294,002 prevented both activation of Akt1 and inhibition of MLK3, MKK4/7 and JNK1/2. The interaction between ERalpha and the p85 subunit of PI3K was also examined. E2 and antiestrogen ICI 182,780 promoted and prevented this interaction, respectively. Furthermore, ICI 182,780 blocked both the activation of Akt1 and the inhibition of MLK3, MKK4/7 and JNK1/2. Photomicrographs of cresyl violet-stained brain sections showed that E2 reduced CA1 neuron loss after 5 days of reperfusion, which was abolished by ICI 182,780 and LY 294,002. Our data indicate that in response to estrogen, ERalpha interacts with PI3K to activate Akt1, which may inhibit the MLK3-MKK4/7-JNK1/2 pathway to protect hippocampal CA1 neurons against global cerebral ischemia in male rats.

The lifetime of CFC substitutes studied by a network trained with chaotic mapping modified genetic algorithm and DFT calculations

The hydrohaloalkanes have attracted much attention as potential substitutes of chlorofluorocarbons (CFCs) that deplete the ozone layer and lead to great high global warming. Having a short atmospheric lifetime is very important for the potential substitutes that may also induce ozone depletion and yield high global warming gases to be put in use. Quantitative structure-activity relationship (QSAR) studies were presented for their lifetimes aided by the quantum chemistry parameters including net charges, Mulliken overlaps, E(HOMO) and E(LUMO) based on the density functional theory (DFT) at B3PW91 level, and the C-H bond dissociation energy based on AM1 calculations. Outstanding features of the logistic mapping, a simple chaotic system, especially the inherent ability to search the space of interest exhaustively have been utilized. The chaotic mapping aided genetic algorithm artificial neural network training scheme (CGANN) showed better performance than the conventional genetic algorithm ANN training when the structure of the data set was not favorable. The lifetimes of HFCs and HCs appeared to be greatly dependent on their energies of the highest occupied molecular orbitals. The perference of the RMSRE comparing to RMSE as objective function of ANN training was better for the samples of interest with relatively short lifetimes. C(2)H(6) and C(3)H(8) as potential green substitutes of CFCs present relatively short lifetimes.

[Differential expression of cyclins D1, E and A in human breast diseases]

OBJECTIVE

To understand with greater clearness the effect of overexpression of cyclins gene and the potential implications of it for tumorgenesis in breast.

METHODS

We assayed the expression of cyclins D1, E and A in different types of human breast diseases by immunohistochemical staining.

RESULTS

Significant difference was seen among the malignant tumor, benign tumor and dysplasis(P < 0.001). The expressive intensity of above three kind of cyclins in malignant tumor was the highest, that in benign tumor was higher, and that in dysplasis was low.

CONCLUSION

These data suggest that the expressive intensity of cyclins gene may serve as an indicator for malignant intensity of tumors. The expressive ratio difference of cyclins E and A between infiltrating ductal carcinoma and infiltrating lobular carcinoma may imply that there are different mechanisms involving the occurrence of different histological types of breast tumor.

Point mutations of muscle mitochondrial DNA from patients with mitochondrial encephalomyopathies

OBJECTIVE

To study the relation between point mutations at nt3243 and nt8344 of muscle mitochondrial DNA from patients with mitochondrial encephalomyopathies and phenotypes.

METHODS

DNA was extracted from muscle specimens from 5 patients with mitochondrial encephalomyopathies and and amplified by PCR method, using corresponding oligonucleotide primers. DNA fragments were digested with restriction enzymes Bgl I and Apa I, then the digested DNA fragments were analyzed with an electrophoresis method.

RESULTS

The point mutation at nt3243 of mtDNA was found in 2 patients, one with mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS) and another with myoclonic epilepsy with ragged red fibers (MERRF). The point mutation at nt8344 was found in 2 patients with MERRF, including the one with point mutation at nt3243.

CONCLUSION

The point mutation of DNA at nt3243 correlated with MELAS and nt8344 correlated with MERRF. In addition, the detection of point mutations at both nt3243 and nt8344 in a patient with MERRF shows the association of mutation with diversity in clinical manifestations of mitochondrial encephalomyopathies.

[Detection of telomerase activity in laryngeal carcinoma and the association between telomerase activity and lymphatic metastasis]

OBJECTIVE

To investigate the telomerase activity in human laryngeal squamous cell carcinomas (LSCC) and the association between telomerase activity and lymphatic metastasis.

METHOD

Telomerase activity was determined in 47 specimens of LSCC and 10 specimens of laryngeal inflammatory polyps using PCR-ELISA.

RESULT

Telomerase activity was detected in 39 of 47 (83%) LSCC, but was not detected in all 10 laryngeal inflammatory polyps. There were significant differences between them (P < 0.01). Telomerase activation in LSCC with positive cervical lymph node involvement appeared to be higher (13 out of 13 cases, 100%) than in LSCC with negative cervical lymph node involvement (26 out of 34, 76.47%), (P < 0.05).

CONCLUSION

Telomerase is activated frequently in LSCC and may become a biomarker of LSCC. The detection of telomerase activity in LSCC may have some value for predicting metastasis potential and prognosis and can guide the clinical practices applying selective neck dissection.

Syntaxin 1A supports voltage-dependent inhibition of alpha1B Ca2+ channels by Gbetagamma in chick sensory neurons

N-type Ca(2+) channels are modulated by a variety of G-protein-coupled pathways. Some pathways produce a transient, voltage-dependent (VD) inhibition of N channel function and involve direct binding of G-protein subunits; others require the activation of intermediate enzymes and produce a longer-lasting, voltage-independent (VI) form of inhibition. The ratio of VD:VI inhibition differs significantly among cell types, suggesting that the two forms of inhibition play unique physiological roles in the nervous system. In this study, we explored mechanisms capable of altering the balance of VD and VI inhibition in chick dorsal root ganglion neurons. We report that (1) VD:VI inhibition is critically dependent on the Gbetagamma concentration, with VI inhibition dominant at low Gbetagamma concentrations, and (2) syntaxin-1A (but not syntaxin-1B) shifts the ratio in favor of VD inhibition by potentiating the VD effects of Gbetagamma. Variations in expression levels of G-proteins and/or syntaxin provide the means to alter over a wide range both the extent and the rate of Ca(2+) influx through N channels.

Cloning and functional expression of novel N-type Ca(2+) channel variants

Voltage-dependent Ca(2+) channels are structurally and functionally diverse. As Ca(2+) currents recorded from embryonic chick dorsal root ganglion (DRG) neurons differ significantly from their mammalian counterparts, information on the primary sequence of the chick channels will help define the structural underpinnings of Ca(2+) channel function. Here, we report the cloning and functional expression of full-length Ca(2+) channel alpha(1B) subunit cDNAs derived from chick DRGs. Two variable regions (A and B) have been identified in the cytoplasmic linker between repeats I and II; a third (C) in the carboxyl terminus extends the open reading frame by 525 nucleotides. The A and C inserts are absent, and the B insert is present in all other class B clones reported to date. The unique shorter channels appear to predominate in DRG neurons. Results represent a requisite first step in defining the structural elements that underlie variations in function and modulation of Ca(2+) channels.

[Ultrastructural study on neuromuscular junction of patients with lambert-Eaton myasthenia syndrome or mitochondrial encephalomyopathy]

OBJECTIVE

To study the ultrastructural changes of neuromuscular junction (NMJ) in patients with lambert-Eaton myasthenia syndrome (LEMS) and mitochondrial encephalomyopathy (MEMS).

METHODS

The MMJ of internal intercostal muscles from patients with LEMS, MEMS or cardiac disease (control group) was labelled by HRP-BuTx and was quantitatively studied using image analysis system on electron microscopic photo.

RESULTS

The ratio of nerve terminal area with postsynaptic membrane of NMJ was less in the MEMS group than controls. Both the length of presynaptic membrane and the ratio of the length of postsynaptic memberane to presynaptic membrane was larger in the LEMS group than in the MEMS group and controls, but the ratio of nerve terminal area with postsynaptic memberane area was less in the LEMS patients than in the MEMS group and controls.

CONCLUSION

The areas of nerve terminal in the MEMS patients shrink because of mitochondrial damage. In LEMS patients however, the major change is the elongation of postsynaptic memberane and increasing of Ach receptors.

Investigation of the misalignment sensitivity of a birefringence-compensated two-rod Nd:YAG laser system

A system for the compensation of thermally induced birefringence in laser rods that consists of two identical Nd:YAG laser rods, a telescope to image the principal planes of the rods onto each other and a 90 degrees quartz rotator to change the state of polarization between the rods has been set up, and its sensitivity to transversal and longitudinal misalignment has been investigated experimentally. A theoretical model to describe the increase of depolarization that is due to misalignment has been developed and compared with the experimental results.

[Ann applied to the prediction of vibration frequencies of octahedral modes (v1 and v2) of MX6(n-) ions (X = F, Cl, Br, I)]

Artificial neural networks back-propagation algorithm was applied to the prediction of vibration frequencies of v1 and v2 modes of octahedral hexahalide (MX6(n-)). Three-layer networks with one and two output nodes were used. Two inertia terms and training step controlling scheme were adopted to weights adjustment. The result of one output node networks has little difference from that of two output nodes networks. The frequencies of [Mof6]2-, [BiF6]- and [AuF6]- from literature are a great deal different from those calculated or predicted values.

[Fetal fibronectin and preterm birth]

OBJECTIVE

To determine whether fetal fibronectin is a sensitive test for the diagnosis and prediction of preterm birth.

METHODS

Fetal fibronectin was measured by enzyme-labeled immunosorbent assay (ELISA) methods in sample of cervical secretion from 38 women with threatened preterm delivery (study group) and 43 normal pregnanty women with same gestational weeks (control group).

RESULTS

The positive rate of fetal fibronectin in women with threatened preterm birth was significantly higher than that in the normal control group.

CONCLUSION

Fetal fibronectin is an important marker. It can be used for diagnosis and prediction of preterm birth.

Silver as a probe of pore-forming residues in a potassium channel

In voltage-dependent potassium channels, the molecular determinants of ion selectivity are found in the P (pore) region, a stretch of 21 contiguous residues. Cysteine was introduced at each P region position in a Shaker potassium channel. Residues projecting side chains into the pore were identified by means of channel inhibition by a sulfhydryl-reactive potassium ion analog, silver ion. The pattern of silver ion reactivity contradicts a beta barrel architecture of potassium channel pores.

Effect of cardiopulmonary bypass on the specific immunity of the host

T cell subsets and immunoglobulin (Ig) were observed sequentially with the OKT monoclonal antibodies rosette test and the rate scattering turbidimetry in 13 patients who underwent open heart surgery under cardiopulmonary bypass (CPB) for rheumatic heart diseases (RHD) and congenital heart diseases (CHD), before and after operation. Compared with preoperative values, in the early period after CPB, T helper cells, T helper cells to T suppressor cells ratio and IgG decreased significantly; whereas T suppressor cells increased, in RHD and CHD. The T cell subsets returned to the preoperative levels two weeks after CPB in RHD and CHD. The IgG came back to the preoperative levels two weeks after CPB in RHD and only one week after CPB in CHD.

Performance of a 2.3-kW Nd:YAG slab laser system

A slab laser system consisting of three Nd:YAG slabs with dimensions 7 mm x 26 mm x 191 mm was operated with different resonators in an oscillator-amplifier-amplifier arrangement. In single-shot operation the system provided a maximum output energy of 148 J with a pulse duration of 4 ms and an overall efficiency of 4.3%. A stable resonator provided a maximum steady output power of 2260 W, and we measured beam parameter products of 8 mm mrad in the x direction and 100 mm mrad in the y direction. An output power of 1460 W and beam parameter products of less than 4 mm mrad in both directions were obtained with an unstable resonator with a graded-reflectivity mirror.

Expression of a partial synthetic human TNF cDNA in E. coli

A recombinant human tumour necrosis factor (rhTNF) cDNA was constructed. The TNF gene was isolated from a human genomic gene library. There are four exons in the TNF gene. The fourth exon codes for 140 amino acids of the TNF matured protein which is composed of 157 amino acids. A major portion of the fourth exon was isolated and then ligated to a synthesized DNA fragment coding for the remaining amino acids. The partial synthetic hTNF (rhTNF) cDNA thus generated was subcloned into a vector and successfully expressed in E. coli. 5-1 fermentator was used to produce rhTNF. About 20 g (wet weight) of bacterial pellet per liter medium and 10(6)-10(7) units of cytotoxicity to L929 cells per milliliter medium were obtained. rhTNF was purified by HPLC and dried with a freeze dryer. rhTNF with a purity of about 95% in the form of white powder was obtained. The sequence of ten amino acids at the amino terminus of the rhTNF was determined. The result showed that it was identical with that of the natural human TNF.

Off-axis prism resonator for improved beam quality of slab lasers

An off-axis prism resonator that was especially designed for slab lasers is investigated. It consists of an output coupling mirror and two 90-deg prisms, one of which is placed off axis. This arrangement permits a fill factor of one and reduces the mode order of the extracted beam compared with that of a conventional stable mirror resonator. Thus a high extraction efficiency and high beam quality are achieved.