[Comparison of different reconstruction procedures after distal gastrectomy in patients with gastric cancer]

Objective: To systematically compare the effect of Roux-en-Y with Billroth Ⅰ or Billroth Ⅱ in gastric cancer patients after distal gastrectomy by meta-analysis. Methods: Systematic search was conducted on the relevant electronic databases of Pubmed, Embase, Wanfang Database, CNKI and VIP from the established time to August 18, 2019. The randomized controlled trials about comparison of Roux-en-Y with Billroth Ⅰ or Billroth Ⅱ were strictly screened and analyzed by the software of Revman 5.3. Procedure and postoperative outcomes were analyzed, respectively. Results: A total of 783 relevant literatures were systematically retrieved, and 6 randomized controlled trials, including 954 patients, finally met the inclusion criteria after strict screening. The results of meta-analysis showed that operative time of Billroth Ⅰ was significantly shorter than that of Roux-en-Y (MD=-37.60, 95%CI:-50.79--24.40, P<0.001), intraoperative bleeding (MD=-21.64, 95%CI:-32.20--11.07, P<0.001) and the number of delayed gastric emptying (RR=0.52, 95%CI: 0.31-0.86, P=0.01) of Billroth Ⅰ were both significantly less than those of Roux-en-Y, while bile reflux (RR=8.17, 95%CI: 2.21-31.53, P=0.002) and residual gastritis (RR=1.75, 95%CI:1.43-2.14, P<0.000 01) of Billroth Ⅰ were both significantly higher than those of Roux-en-Y, other outcomes showed no significant difference. Compared with Roux-en-Y, operative time of Billroth Ⅱ was significantly shorter (MD=-19.73, 95%CI:-32.82--6.64, P=0.003), while bile reflux (RR=17.63, 95%CI: 4.50-69.02, P<0.001), residual gastritis (RR=1.94, 95%CI:1.15-3.26, P=0.01) and reflux esophagitis (RR=3.13, 95%CI: 1.31-7.45, P=0.01) of Billroth Ⅱ were all significantly higher, and there was no significant difference in other outcomes. Conclusion: Compared with Billroth Ⅰ and Billroth Ⅱ, the operation time of Roux-en-Y in gastric cancer patients undergoing distal gastrectomy is longer, but the incidences of bile reflux and residual gastritis are both lower, and the postoperative quality of life seems better.

Predicting non-elective hospital readmission or death using a composite assessment of cognitive impairment and frailty in elderly inpatients with cardiovascular diseases

Background

Cardiovascular disease (CVD) and related complications are significant healthcare problems in the growing elderly population. Metabolic factors are the predominant risk factors for CVD, sedentary behaviour and physical inactivity are major modifiable risk factors for CVD. Age-associated cognitive decline and impairment are associated with an increased mortality. Cognitive and physical components of frailty have pathophysiologic rationale as risk factors for CVD. There is a clinical need to identify more practical screens that can assist us to definite cognitive impairment and physical frailty, then to determine which patients with CVD are at high risk of adverse outcomes, early management of these high-risk patients can reduce readmission rates, healthcare spending, and improve quality of care.

Purpose

We aimed to assess the utility of a combination developed using the mini-mental state examination + clock drawing test and the Fried phenotype for predicting non-elective hospital readmission or death within 6-month in elderly inpatients with CVD.

Methods

A single center prospective cohort was conducted between September 2018 and February 2019. Inpatients aged 65 years or older were recruited. All enrolled patients received a comprehensive geriatric assessment during hospitalization. The Kaplan-Meier curves were used to estimate the cumulative incidence of events. The multivariate Cox regression model was used to analyze the association between frailty and cognitive status and the non-elective hospital readmission or death.

Results

A total of 542 patients were included; and a total of 113 patients (20.9%) died or were readmitted at 6-month. Overall 20% screened positive for cognitive impairment, including 8% were cognitive impairment combined with physical frailty, which were more older, more common in women and non-married group, had a lower education and a higher risk of malnutrition. Frail participants with normal (hazard ratio [HR]: 1.73, 95% confidence intervals [CI]: 1.06–2.82, P=0.028) and impaired cognition (HR: 2.50, 95% CI: 1.27–4.91, P=0.008) had a higher risk of non-elective hospital readmission or death than robust patients, after adjustment for age, sex, education level, marital status, the presence of diabetes mellitus, heart failure, and previous stroke.

Conclusions

The presence of physical frailty and cognitive frailty were powerful predictors of non-elective hospital readmission or death in elderly inpatients with CVD, and taking cognitive impairment into account in the frailty model may allow better prediction of adverse outcomes of frailty in the short time.

Kaplan-Meier survival curves

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Beijing Municipal Science & Technology Commission, Chinese Academy of Medical Sciences

Correlation between COX-2 gene polymorphism and susceptibility to nasopharyngeal carcinoma

OBJECTIVE

The aim of this study was to investigate cyclooxygenase-2 (COX-2) gene polymorphism in peripheral blood cells of patients with nasopharyngeal carcinoma (NPC) and normal people, and to explore the correlation between polymorphism and the occurrence of NPC.

PATIENTS AND METHODS

The genotype and allele distributions of gene loci COX-2-899 (G/C) and COX-2-1195 (G/A) in peripheral blood of 56 normal people and 114 NPC patients were analyzed via reverse transcription-polymerase chain reaction (RT-PCR). The genetic equilibrium was detected by TaqMan genotyping technique. Meanwhile, the risk factors for NPC were analyzed via multivariate logistic regression analysis. Subsequently, the effects of risk factors, clinical features, and gene polymorphism of NPC on the prognosis and survival of patients were analyzed using univariate and multivariate COX regression analysis. Finally, the correlation of smoking, Epstein-Barr (EB) virus infection and COX-2-1195 gene polymorphism with NPC was explored via χ2-test.

RESULTS

There was a significant difference in the genotype and allele distributions at COX-2-1195 (G/A) between the two groups (p<0.05). However, no significant differences were observed at COX-2-899 (G/C) between the two groups (p>0.05). According to the results of univariate and multivariate COX regression analysis, smoking and EB virus infection were risk factors for NPC (p<0.05). The χ2-test indicated that there was an evident gene polymorphism at COX-2-1195 in smokers and EB virus-infected people compared to non-smokers and non-infected people (p<0.05).

CONCLUSIONS

COX-2-1195 gene polymorphism is associated with susceptibility to NPC. Smoking and EB virus infection are major risk factors for NPC, both of which can affect COX-2-1195 gene polymorphism.

Volcanic origin for Younger Dryas geochemical anomalies ca. 12,900 cal B.P

The Younger Dryas (YD) abrupt cooling event ca. 12.9 ± 0.1 ka is associated with substantial meltwater input into the North Atlantic Ocean, reversing deglacial warming. One controversial and prevailing hypothesis is that a bolide impact or airburst is responsible for these environmental changes. Here, highly siderophile element (HSE; Os, Ir, Ru, Pt, Pd, and Re) abundances and 187Os/188Os ratios were obtained in a well-dated sediment section at Hall's Cave, TX, USA to test this hypothesis. In Hall's Cave, layers below, above, and in the YD have 187Os/188Os ratios consistent with incorporation of extraterrestrial or mantle-derived material. The HSE abundances indicate that these layers contain volcanic gas aerosols and not extraterrestrial materials. The most likely explanation is that episodic, distant volcanic emissions were deposited in Hall's Cave sediments. Coupled 187Os/188Os ratios and HSE concentration data at close stratigraphic intervals are required to effectively differentiate between bolide and volcanic origins.

[Iodine status of vulnerable populations in Henan Province of China three years after the implementation of new iodized salt standard]

Iodine nutrition surveillance of vulnerable population was conducted in 18 cities of Henan Province in 2015. The medians and quartiles of urinary iodine concentration in women of reproductive-age (n=3 318), pregnant women (n=36 366), lactating women (n=4 153), infants <2 years of age (n=1 017), and children aged 8-10 years (n=4 806) were 202.1(124.0, 310.0), 192.4(133.6, 262.4), 168.3(119.1, 248.3), 214.2(156.1, 272.3) and 90.0 (121.8, 285.6) μg/L, respectively. Iodine status of the vulnerable populations was generally regarded as adequate in Henan Province. But the median of urinary iodine concentration of reproductive-age women were slightly above the adequate level. The proportions above iodine adequate level were 26.7% in reproductive-age women, 29.4% in pregnant women and 22.5% in children aged 8-10 years.

Experience of pediatric urogenital tract inserted objects: 10-year single-center study

INTRODUCTION

Urogenital tract foreign bodies (FBs) have been rarely reported in children, and the management is still challenging.

OBJECTIVE

The aim of this study is to review a 10-year experience with urogenital tract FBs in a single center.

PATIENTS AND METHODS

The authors reviewed the records of children suspected with urogenital tract FBs and first admitted to the hospital, including demographic characteristics, presenting symptoms, methods of diagnosis, and management. The authors compared the surgery strategies in different locations of FBs and age, and the locations of FBs in different age groups.

RESULTS

Two hundred and thirty-nine cases were reviewed, and 188 were confirmed to retain urogenital tract FBs (150 girls and 38 boys). The number of the patients increased progressively in the last 10 years and mainly concentrated in spring and summer in the last 4 years. The peak ages were 3-5 years old and 9-13 years old. General anesthesia surgeries were performed on 20 patients (Fig. 1). Vagina FBs were more likely to require day surgery, whereas bladder FBs required surgery in hospital. Patients younger than 6 years were more likely to be girls with vagina FBs, and patients older than 11 years were more likely to be boys with bladder FBs.

DISCUSSION

Urogenital tract FBs in children is a great challenge. As the vagina is shorter and wider than the urethra, girls with vagina FBs are usually treated by day surgery and adolescent boys of urethra FBs are treated by hospital surgery. Misdiagnosis may occur when patients conceal FBs insert history, have severe urinary tract infections, or have previous surgery history. Ultrasonography helps to reduce misdiagnosis. FBs should be taken into consideration when patients have new symptoms after hypospadias repair, and postoperative changes of hypospadias repair, such as urinary calculi, have been excluded. Appropriate surgery techniques, based on the size, nature, and location of FBs, should be performed for complete removal of FBs with minimal complications to reduce secondary injury. Sharp FBs could be migrated among the digestive system, urogenital system, and deep pelvic. If the procedure is difficult, patients with a stable needle can be conservatively managed with close follow-up. Nevertheless, symptomatic patients should be treated actively.

CONCLUSION

The awareness of potential severity of pediatric urogenital tract FBs should be raised. Appropriate toys and timely sex education help prevent children from urogenital tract FBs insertion. Selecting appropriate techniques for particular situations is the best way to reduce secondary injury, especially for cases with migrated FBs (needles), magnetic FBs, and postoperative FBs.

Ewing sarcoma/primitive neuro-ectodermal tumor of the urogenital system in children: a retrospective observational case series

INTRODUCTION

Pediatric Ewing sarcoma (ES)/primitive neuro-ectodermal tumor (PNET) occurring in the genitourinary system has been rarely reported. And the result of long-term follow-up is still a matter of debate.

OBJECTIVE

The aim of the study was to identify the characteristics, therapeutic strategies, and long-term outcomes of pediatric ES/PNET in the genitourinary system.

PATIENTS AND METHODS

All children with genitourinary system PNET from a single center were retrospectively reviewed. The American Joint Committee on Cancer (AJCC) staging system was used to evaluate tumor grade.

RESULTS

Four patients were included. Three were boys, and 1 was a girl. The locations of the lesions were the penis in 1 patient, ureter in 1 patient, and kidney in 2 patients. Two patients were of AJCC stage IVB, and the other 2 patients were of stage IIA. In the follow-up ranging from 2.5 to 8.0 years, 3 patients had survival, and 1 patient died. The patient with penis PNET survived during the 8 years of follow-up. One patient with renal PNET had tumor thromboses in the renal vein, inferior vena cava, and right atrium, which was the first definite report in children (case 3).

DISCUSSION

Primitive neuro-ectodermal tumor as a highly malignant subgroup of blue round cell tumor is extremely rare in the genitourinary system, especially in children. The current case series represents the first report of penis PNET in children with the longest (8 years) follow-up and first definite report of pediatric renal PNET with vena cava and atrium tumor thrombus. In contrast to the previous literature, the patient with ureteral PNET in this study was much younger, who was the youngest child to be reported in the literature thus far. Although the key prognostic factor of the outcomes is detectable metastases at diagnosis, the patient with penis PNET and bone and lung metastasis in this series still survived. It was hypothesized from the data of present cases that young age was a protective factor, which was consistent with the previous literature. Aggressive therapy is not trivial for patients with multiple recurrences who can also be a long-term survivor. The survival outcomes of these high-stage patients were favorable with combination treatment. As the patient with penis PNET in this series had bone metastasis at his 7.5 years after definite diagnosis, five years of follow-up was not enough. The follow-up period should be extended, even to a lifetime follow-up.

CONCLUSIONS

Children with PNET have a better prognosis than adults. Aggressive combination treatment should be performed to improve prognosis and the survival rate. It is better to monitor the changes of the disease by extending the follow-up period.

Disposition kinetics of orbifloxacin in tissues of crucian carp (Carassius auratus) following a single intramuscular administration

BACKGROUND

Orbifloxacin is being widely used in China to treat fish infections in an extra-label manner, which may cause its potential residues in edible tissues.

AIMS

The purpose of this study was to determine the disposition kinetics of orbifloxacin in crucian carp (Carassius auratus) following intramuscular administration for its further safe application in aquaculture industry.

METHODS

Tissue samples of skin, muscle, kidney, and liver were collected from six crucian carps reared at 25°C at 5, 10, 15, 30, 45 min, 1, 2, 4, 6, 12, 24, 48, 72, and 96 h following a single intramuscular injection at 7.5 mg/kg body weight (BW). The orbifloxacin concentrations in tissues were determined using a high-performance liquid chromatography (HPLC) method with a fluorescence detector, then average concentrations versus time data were subjected to non-compartmental analysis to obtain the kinetic parameters.

RESULTS

The peak concentration of 5.68 ± 0.03 µg/g was calculated in kidney at 2 h, followed by muscle (5.51 ± 0.01 µg/g) at 4 h, liver (4.84 ± 0.20 µg/g) at 2 h, and skin (4.27 ± 0.08 µg/g) at 4 h. Area under concentration-time curve was calculated as 79.22, 94.72, 118.65, and 129.02 h·µg/g in kidney, liver, skin, and muscle, respectively. And the elimination half-lives were determined as 18.17, 18.41, 18.77, and 19.11 h in skin, kidney, muscle, and liver, respectively.

CONCLUSION

It was shown that orbifloxacin was well distributed into tissues while relatively slowly eliminated in crucian carp reared at 25°C following a single intramuscular injection.

[Association between hyponatremia and hemodynamic and prognosis in patients with intermediate-risk acute pulmonary embolism]

Objective: To investigate the association between hyponatremia and hemodynamic and prognosis in patients with intermediate-risk acute pulmonary embolism. Methods: We retrospectively recruited 110 intermediate-risk acute pulmonary embolism patients (right ventricular dysfunction was confirmed by echocardiography and CT scan with or without the elevated levels of cardiac injury biomarkers) in the first and the second affiliated hospital of Harbin medical university from January 1,2011 to December 31, 2014. The patients were aged (58.4±14.9) years old.There were 49 males and 61 females.Patients were divided into 2 groups as non-hyponatremia group (plasma sodium>135 mmol/L, 93 cases) and hyponatremia group (plasma sodium≤135 mmol/L, 17 cases). Baseline clinical and hemodynamic parameters were obtained from these patients. All enrolled patients were followed up after discharge. Results: Heart rate ((106.7±21.9) beats per minute vs. (93.4±19.4) beats per minute, P=0.043),N-terminal pro B type natriuretic peptide (NT-proBNP, (5 561±1 593) ng/L vs. (1 738±589) ng/L, P=0.005), mean pulmonary arterial pressure((42.6±12.6)mmHg(1 mmHg=0.133 kPa) vs. (33.9±13.3)mmHg, P=0.046), mean right atria pressure ((20.6±8.1)mmHg vs. (10.2±5.4)mmHg, P=0.014), systolic right atria pressure ((27.3±9.0)mmHg vs. (15.6±6.1)mmHg,P=0.013) and diastolic right atria pressure(6.5(4.3,15.5)mmHg vs. 5.0(2.0,8.0)mmHg,P=0.016) were significantly higher in hyponatremia group than in non-hyponatremia group,and systolic blood pressure was significantly lower in hyponatremia group than in non-hyponatremia group ((113.5±21.9)mmHg vs.(129.5±28.9)mmHg, P=0.048). Pearson correlation analysis showed that hyponatremia was negatively correlated with heart rate (r=-0.262, P=0.043), NT-proBNP (r=-0.227, P=0.048), mean pulmonary arterial hypertension (r=-0.259, P=0.046), mean right ventricular pressure (r=-0.296, P=0.047), mean right atria pressure (r=-0.550, P=0.001), systolic right atria pressure (r=-0.552, P=0.001), and diastolic right atria pressure (r=-0.542, P=0.001). Kaplan-Meier survival analysis showed that the 1-year, 2-year and 3-year cumulative survival rates were 76.5%,70.6%,and 64.7% in the hyponatremia group, and 90.3%,86.0%,and 83.9% in the non-hyponatremia group(log-rank test, P=0.036).Multivariate Cox regression analysis showed that hyponatremia was an independent risk factor of death of intermediate-risk pulmonary embolism patient(HR=4.126, 95%CI 1.982-11.343, P=0.036). Conclusion: Hyponatremia is associated with adverse hemodynamic and reduced survival in patients with intermediate-risk pulmonary embolism.

[Clinical relevance of common inhibitory immune checkpoint genes in esophageal squamous cell carcinoma]

Objective: To analyze the potential clinical relevance of inhibitory immune checkpoint genes, including PD1, PD-L1, CTLA4, LAG3 and TIM3 in esophageal squamous cell carcinoma (ESCC). Methods: Expression were extracted from mRNA microarray data from 119 paired ESCC and adjacent normal tissues, which were collected from National Cancer Center/Chinese Academy of Medical Sciences between December 2005 and December 2007.Differential expression analyses and survival analyses were then performed to identify potential clinical relevance using R software. Results: Expression of PD-L1, CTLA4, LAG3 and TIM3 were significantly upregulated in ESCC tissues compared with adjacent normal tissues (P<0.05). CTLA4 was significantly correlated with tumor location and age (P<0.05). PD1 and LAG3 were significantly associated with overall survival and were favorable prognostic factors in ESCC. Conclusions: Inhibitory immune checkpoint genes are commonly overexpressed in ESCC and are significantly associated with patients overall survival.These results provide important references in the application of immune checkpoints therapy in ESCC.

[Deltoid ligament augmentation and repairing in ankle fracture associated with deltoid ligament injury and syndesmosis diastasis]

Objective: To evaluate the outcome of the deep component augmentation and superficial component repairing and syndesmosis screw fixation in treating ankle fracture associated with deltoid ligament injury and syndesmosis diastasis. Methods: From January 2014 to December 2017, 16 patients with ankle fracture combined with deltoid ligament injury and syndesmosis diastasis were treated with the deep component augmentation and superficial component repairing in Beijing Jishuitan Hospital.Of the patients, 13 were males and 3 were females, with an average age of (38±10) years (21-57 years). Nine cases were athletic injuries, 4 cases were daily-life injuries and 3 cases were traffic injuries.According to the Weber classification, 6 cases were type B, 10 cases were type C. According to the Lauge-Hansen classification, 6 cases were supination external rotation Ⅳ injury, 9 cases were pronation external rotation Ⅳ injury, 1 case was pronation abduction Ⅲ injury.The surgical treatment method was rigid fixation of the lateral malleolus and deep deltoid ligament augamentation instead of syndesmosis screw fixation.The effect of the surgical method was observed. Results: The average follow up was (24±12) months (6-40 months). The mean degree of dorsiflexion was 17.8°±6.8° (5°-30°), with 3.8°±6.0° (0°-15°) less than that in normal side, the mean degree of plantar flexion was 46.9°±7.9°, with 1.9°±3.9° (0°-10°) less than that in normal side.The mean Philips and Schwartz score was 96.8±5.1 (82-100), the American Orthopaedic Foot and Ankle Society (AOFAS) Score was 97.4±4.6 (84-100). Conclusion: In the treatment of ankle fracture associated with deltoid ligament injury and syndesmosis diastasis, the deep component augmentation and superficial component repairing and proper rehabilitation can benefit the functional recovery.

[Diagnostic value of protein markers in plasma exosomes of lung squamous cell carcinoma]

Objective: To investigate the tumor-associated protein molecules carried by plasma exosomes of patients with lung squamous cell carcinoma before treatment and analyze their value as clinical markers. Methods: Exosomes from 2 patients with lung squamous cell carcinoma before treatment and 2 healthy controls were collected by ultracentrifugation. Proteomics was applied to analyze the protein expression profiles of exosomes. Candidate molecules were verified in another 30 exosomes samples from lung squamous cell carcinoma and healthy controls using enzyme-linked immunosorbent assay (ELISA). Results: Electron microscopy and particle-counting assay showed that high-quality exosomes were collected. The number of exosomes distributed from 45 to 135 nm in 2 cases of lung cancer patients were 7.89×10(11)/ml and 9.71×10(11)/ml, respectively, significantly higher than 2.76×10(11)/ml and 1.41×10(11)/ml in healthy controls. Proteomic analysis showed that proteins of exosomes in lung squamous cell carcinoma patients were very different from those of healthy controls, and some proteins are related to important functions in tumor progression. 14-3-3ζ from exosomes was selected and further verified as a marker, and the area under the receiver operating characteristic curve (ROC) was 0.68. The sensitivity and specificity of 14-3-3 ζ from exosomes were 60.0% and 80.0%, respectively, suggested that it could be used as a diagnostic marker for lung squamous cell carcinoma. Conclusion: The exosome counts in plasma and the protein molecules from exosomes, such as 14-3-3ζ, are closely related to the tumorigenesis, which can be used to assist clinical diagnosis of lung squamous cell carcinoma patients.

[Risk factors analysis and prognosis of renal pelvis dilatation in high-risk infants in monocenter]

Objective: To explore the prognosis and risk factors of pyelectasis in high-risk infants. Methods: This was a retrospective study. Totally 960 high-risk infants, who accepted type B ultrasonic examination for fetus at 28th week of gestation and for newborns in 48 hours after birth, were included in the study in departments of obstetrics and eonatology, Shunyi Maternal and Children's Hospital of Beijing Children's Hospital during May 2012 to April 2013. The degree of pyelectasis was classified using Grignon grade and the paients were followed up for 3 years. The factors of epidemiology, high risk pregnant women, fetus and high-risk newborns that relate to pyelectasis were summarized. High-risk factors were analyzed by using logistic multivariate regression analysis. Results: Of 960 high-risk infants, 103 had abnormal urinary ultrasound results, 87 (9.1% of high-risk infants) were diagnosed with pyelectasis, 16 (1.7% of high-risk infants) were diagnosed with congenital anomalies of the kidney and urinary tract. According to the degree of pyelectasis, 68 infants were Grignon grade Ⅰ, male:female ratio=5.8∶1, left side:right side ratio=1.91∶1; 19 infants were Grignon grade Ⅱ, male:female ratio=5.33∶1, left side:right side ratio=2.12∶1. Postnatal follow-up results showed that pyelectasis disappeared in 48 cases (55% of pyelectasis cae), 40 infants were Grignon grade Ⅰ (59% of all Grignon grade Ⅰ patients), 8 infants were Grignon grade Ⅱ (42% of all Grignon grade Ⅱ patients); The result of risk factors analysis showed that the risk of pyelectasis in males was 4.368 times that of females (95%CI: 2.33-8.189, P<0.05); the risk of pyelectasis in low birth weight infants was 22.434 times that of non low birth weight infants (95% CI: 5.883-85.547, P<0.05). Conclusion: The incidence of pyelectasis in high-risk infants was 9.1%. The mitigation rate of pyelectasis in Grignon grade Ⅰ to Ⅱ in fetal or newborn period is high. Patients in Grignon grade Ⅲ and above in fetal or new born period had high risk of congenital anomalies of the kidney and urinary tract. The risk of pyelectasis of male was higher than that of female; the risk of pyelectasis of low birth weight infant was higher than appropriate for gestational age infants.

Production of recombinant human tektin 1, 2, and 4 and in vitro assembly of human tektin 1

Proteins predicted to be composed of large stretches of coiled-coil structure have often proven difficult to crystallize for structural determination. We have successfully applied EPR spectroscopic techniques to the study of the structure and assembly of full-length human vimentin assembled into native 11 nm filaments, in physiologic solution, circumventing the limitations of crystallizing shorter peptide sequences. Tektins are a small family of highly alpha helical filamentous proteins found in the doublet microtubules of cilia and related structures. Tektins exhibit several similarities to intermediate filaments (IFs): moderate molecular weight, highly alpha helical, hypothesized to be coiled-coil, and homo- and heteromeric assembly into long smooth filaments. In this report, we show the application of IF research methodologies to the study of tektin structure and assembly. To begin in vitro studies, expression constructs for human tektins 1, 2, and 4 were synthesized. Recombinant tektins were produced in E. coli and purified by chromatography. Preparations of tektin 1 successfully formed filaments. The recombinant human tektin 1 was used to produce antibodies which recognized an antigen in mouse testes, most likely present in sperm flagella. Finally, we report the creation of seven mutants to analyze predictions of coiled-coil structure in the rod 1A domain of tektin 1. Although this region is predicted to be coiled-coil, our EPR analysis does not reflect the parallel, in register, coiled-coil structure as demonstrated in vimentin and kinesin. These results document that tektin can be successfully expressed and assembled in vitro, and that SDSL EPR techniques can be used for structural analysis.