Impact of Alcian blue and periodic acid Schiff expression on the prognosis of gastric signet ring cell carcinoma

BACKGROUND

The Alcian blue (AB) and periodic acid Schiff (PAS) stains are representative mucus markers in gastric signet ring cell carcinoma (SRCC). They are low-cost special staining methods used to detect acidic mucus and neutral mucus, respectively. However, the clinical importance of the special combined AB and PAS stain is unclear.

AIM

To investigate AB expression, PAS expression and the AB-to-PAS (A/P) ratio in gastric SRCC patients and to assess patient prognosis.

METHODS

Paraffin-embedded sections from 83 patients with gastric SRCC were stained with AB and PAS, and signet ring cell positivity was assessed quantitatively. Immunohistochemical staining for Ki67, protein 53 (P53) and human epidermal growth factor receptor 2 (HER2) was performed simultaneously. The cancer-specific survival (CSS) rate was estimated via Kaplan-Meier analysis. Cox proportional hazards models were used for univariate and multivariate survival analyses.

RESULTS

Kaplan-Meier survival analysis revealed that the 3-year CSS rate was significantly greater in the high-PAS-expression subgroup than in the low-PAS-expression subgroup (P < 0.001). The 3-year CSS rate in the A/P ≤ 0.5 group was significantly greater than that in the A/P > 0.5 group (P = 0.042). Univariate Cox regression analysis revealed that the factors affecting prognosis included tumor diameter, lymph node metastasis, vessel carcinoma embolus, tumor stage, the A/P ratio and the expression of Ki67, P53 and the PAS. Cox multivariate regression analysis confirmed that low PAS expression [hazard ratio (HR) = 3.809, 95% confidence interval (CI): 1.563-9.283, P = 0.003] and large tumor diameter (HR = 2.761, 95%CI: 1.086-7.020, P = 0.033) were independent risk factors for poor prognosis.

CONCLUSION

A/P > 0.5 is potentially a risk factor for prognosis, and low PAS expression is an independent risk factor in the prognosis of gastric SRCC. PAS expression and the A/P ratio could help in predicting the clinical prognosis of patients with SRCC.

[Research progress in the promotion of peri-implant soft tissue integration of dental titanium implant based on immune microenvironment regulation]

A good integration of dental implants and the surrounding soft tissue is essential to ensure the long-term effect of implant. In this review, we summarized the research progress of peri-implant soft tissue integration of dental titanium implants, with emphasis on the modification of the gingival interface of implants based on immune microenvironment regulation. This method influences the immune response around the implant by promoting the surface properties of implants, so as to enhance the peri-implant soft tissue integration. The purpose of this review is to provide reference for the related research and clinical application in the field of dental implantation.

[Development and implementation of common data sets for venous thromboembolism: current situation and application prospects]

Venous thromboembolism (VTE) is a formidable disease that poses a serious threat to the health and well-being of hospitalized patients. Owing to its high incidence, debilitating morbidity, and alarming mortality rates, VTE has gained increasing attention from the clinical medicine community worldwide. Unfortunately, the current state of clinical prevention and treatment of VTE is not very optimistic, necessitating the establishment of large disease-specific databases and real-world studies, which can accumulate effective evidence-based medical evidence to gradually standardize the clinical prevention and treatment and quality control of VTE. The construction and development of large medical databases depend greatly on standardized datasets, which establish the conceptual data models of VTE through data standardization routes, set the object classes according to the model, define the attributes of the classes, standardize the data types and property values, and organize the standardized data elements. This article focuses on providing an in-depth overview of the unique characteristics of various domestic and foreign VTE datasets, describing their application and research progress in VTE, as well as the role of datasets in standardizing clinical and research practices to strengthen quality control and artificial intelligence. Through this comprehensive discussion, we hope to promote the establishment of VTE datasets and enable their use in high-quality large real-world studies.

[Radiation-induced intestinal fibrosis: pathological assessment and pharmacological prevention]

Although radiotherapy can improve the local control rate of tumors and prolong the survival period of patients, it can also lead to long-term adverse effects such as radiation-induced intestinal fibrosis. Radiation-induced intestinal fibrosis has a high incidence and poses significant challenges to treatment, severely impacting the quality of life of patients. Combining findings from domestic and international research, along with experiences of our center, this article mainly discusses the pathological changes of radiation-induced intestinal fibrosis, as well as the current status and challenges of pathological assessment and pharmacological prevention of this condition. At present, there is no definitive method to reverse the fibrotic pathological changes. Thus, the prevention of fibrosis is a crucial issue to be resolved. In the meantime, there is a lack of ideal assessment methods and effective preventive medications in clinical practice. It is necessary to enhance both basic and clinical research, thoroughly investigate the pathogenesis of the disease, and identify effective intervention targets to promote the diagnosis and treatment of radiation-induced intestinal fibrosis.

[Analysis of glucose changes in adults with type 1 diabetes mellitus within 1 year after using mobile APP decision support system]

Objective: To analyze the changes in glucose after using a decision support system (DSS) of a smartphone mobile application (APP) in adults with type 1 diabetes mellitus (T1DM). Methods: In the intervention study, the data (including general information at the time of registration) of adult T1DM patients enrolled in the Chinese T1DM Registration Management Project and registered with TangTangQuan® APP were collected. Within 1 year after registration, fasting blood glucose, pre-prandial and postprandial blood glucose at the three meals, blood glucose before bedtime and in nocturnal time were collected every 3 months. Frequencies of total recorded glucose values and proportion of different ranges of glycemia were also collected and analyzed, including the range between 3.9-7.8 mmol/L (Euglycemia), ranged below 3.9 mmol/L (Hypoglycemia) and range above 13.9 mmol/L (hyperglycemia). The patients were divided into 3 groups according to the daily use frequency of DSS (Low/Moderate/High frequency groups). The changes in point blood glucose, the proportion of hyperglycemia and hypoglycemia over time were compared among different groups, as well as the baseline characteristics and glucose characteristics of patients. Results: A total of 629 eligible T1DM patients were included, including 216 (34.3%) males and 413 (65.7%) females, aged (31.5±10.8) years, and disease duration [M(Q₁, Q₃)] of 1.2 (0.1, 7.4) years. There were 239, 189 and 201 patients in the low, moderate and high frequency groups, respectively. Significant differences were observed among the three groups in all timepoints of self-monitoring blood glucose except for the glucose before bedtime from 10 to 12 months after registration (all P values<0.05), and the glucose level at each point in the high frequency group was lower than that in the other two groups. In the first three months after registration, there was no difference in the proportion of hypoglycemia among the three groups (P>0.05). However, from 10 to 12 months after registration, the proportion [M(Q₁, Q₃)] of hypoglycemia [3.34% (0.85%, 7.40%), 3.00% (0.78%, 6.17%), 1.81% (0.37%, 4.69%)] (P=0.022) between groups (from low to high frequency groups) and hyperglycemia [4.04% (0, 12.16%), 1.88% (0, 7.80%), 0.81% (0, 3.87%)] (P=0.001) were significantly different. Conclusions: The DSS function of mobile APP is helpful to the glucose management of adult patients with T1DM within 1 year after registration. The average blood glucose in adults with T1DM decreased, and the proportions of hyperglycemia and hypoglycemia were also reduced.

Measurement of the Cosmic Ray Helium Energy Spectrum from 70 GeV to 80 TeV with the DAMPE Space Mission

The measurement of the energy spectrum of cosmic ray helium nuclei from 70 GeV to 80 TeV using 4.5 years of data recorded by the Dark Matter Particle Explorer (DAMPE) is reported in this work. A hardening of the spectrum is observed at an energy of about 1.3 TeV, similar to previous observations. In addition, a spectral softening at about 34 TeV is revealed for the first time with large statistics and well controlled systematic uncertainties, with an overall significance of 4.3σ. The DAMPE spectral measurements of both cosmic protons and helium nuclei suggest a particle charge dependent softening energy, although with current uncertainties a dependence on the number of nucleons cannot be ruled out.

Meta-analysis: Supplementary artificial light and goose reproduction

Photoperiod affects poultry reproduction, and in birds, photoperiod regulation is a complex physiological process. In modern poultry production, lighting management has become an important and effective management approach for increasing egg production. Geese are domesticated fowl and in many goose production enterprises animals are allowed to roam in outside pens during the day and are housed indoors at night, so the animals can be exposed to artificial lighting during the night periods. Supplementary artificial lighting resulted in improved reproduction in some studies, but reports have been inconsistent. To evaluate the results from previous studies of supplementary lighting on goose egg production, a meta-analysis was conducted to determine optimal supplementary artificial lighting regimens for geese egg production. Results indicated supplementary artificial light increases mean egg production, the length of the period of egg production before there is cessation of egg production capacity, and fertility. In summary, there were evaluations of data from five studies focused on White Roman geese in the meta-analysis conducted in the present study, however, examination of more breeds is necessary to make more definitive assessments of the findings from this meta-analysis.

[Epidemiological and pathogenic characteristics of mumps in Fujian province, 2005-2017]

Objective: To understand the epidemiological and etiological characteristics of mumps in Fujian province, 2005-2017. Methods: All the reported mumps cases were collected through the National Notifiable Disease Information Management System, 2005-2017. Active search and interviews were conducted to collect the information on vaccination of mumps. Throat swab specimens were collected for cells culture, genotyping and gene sequence analysis on mumps virus (MuV). Results: A total of 83 959 cases of mumps were reported in Fujian province from 2005 to 2017, with an average annual incidence of 17.6 per 100 000. Since 2007, the incidence appeared increasing but then decreasing, reaching the lowest level (7.5 per 100 000), after the setup of a monitoring program. Annually, the onset time of mumps showed an obvious two seasonal peaks, one from April to July, with a weakening trend, and the other from October to January with a rising trend. Most of the mumps cases occurred among students, kindergarten and scattered children (89.2%, 5 814/6 517), children aged 5-9 years (38.8%, 2 527/6 517), with cases reported from every region. Program from the pathogen surveillance showed that the transmission chain of G genotype mumps virus did exist in Fujian. Data from the sequence analysis revealed that mutations in the nucleotide of G genotype strain in 2015 had led to mutation of 6 amino acid sites in the SH gene coding region, resulting in the differences appearing in both nucleotide and amino acid homology with type A vaccine strain. Conclusions: The incidence of mumps decreased annually, in Fujian. Prevention programs should focus on primary and secondary school students. In Fujian province, we also noticed the transmission chain of mumps G genotype with some amino acid mutations in the SH gene coding region. Monitor programs on both epidemiologic and etiology, should be strengthened.

Second-harmonic imaging microscopy for identifying colorectal intraepithelial neoplasia

In this study, second-harmonic imaging microscopy was used to monitor precancerous colorectal lesions at different stages. It was found that the morphology of glands and lamina propria in mucosa changes with the progression of colorectal diseases from normal to low-grade intraepithelial neoplasia to high-grade intraepithelial neoplasia and this microscopy has the ability of direct visualization of these warning symptoms. Furthermore, two morphologic variables were quantified to determine the changes of glands and collagen in lamina propria during the development of colorectal intraepithelial neoplasia. These results suggest that second-harmonic imaging microscopy has the potential in label-freely and effectively distinguishing between normal and precancerous colorectal tissues, and will be helpful for early diagnosis and treatment of colorectal diseases.

[Experimental study of GeneXpert(®) system in the diagnosis of extra-pulmonary tuberculosis]

OBJECTIVE

To explore the application value of GeneXpert MTB/RIF for detection of extra-pulmonary tuberculosis and resistance to rifampin.

METHODS

A total of 150 samples were collected, including 33 needle aspirates from lymphoid tuberculosis, 23 needle aspirates from spinal tuberculosis, 49 from tuberculous pleural effusions, 24 from cerebrospinal fluid of tuberculous cephalomeningitis, and 21 urinary sediment samples from renal tuberculosis. Smear microscopy, mycobacterium tuberculosis culture and the MTB/RIF method were used to examine these samples and their positive rates were compared. Rifampin susceptibility tests was performed for culture-positive strains using proportion method, which was compared with the result from GeneXpert MTB/RIF method.

RESULTS

Of the 150 cases of extra-pulmonary tuberculosis, 17 samples were smear-positive, with a sensitivity of 11.3% (17/150); 30 were culture-positive with a sensitivity of 20.0% (30/150); and 96 were positive by MTB/RIF method with a sensitivity of 64.0% (96/150). There was a significant difference between MTB/RIF method and the culture method (χ(2)=59.61, P<0.01). The differences were also significant when the MTB/RIF method was compared with the smear method (χ(2)=88.60, P<0.01) or compared with culture plus smear methods (χ(2)=4.26, P<0.05). Separately, the differences were statistically significant between GeneXpert MTB/RIF method and other 2 methods for diagnosis of lymphoid tuberculosis (n=33, χ(2)=20.56, P<0.01 vs. culture method; χ(2)=27.13, P<0.01 vs. smear results) while no difference was found between culture and smear method (χ(2)=0.67, P>0.05), spinal tuberculosis (n=23, χ(2)=12.74, P<0.01 vs. culture method; χ(2)=14.81, P< 0.01 vs. smear method), tuberculous pleurisy (n=49, χ(2)=32.34, P<0.01 vs.culture method; χ(2)=49.69, P<0.01 vs. smear method) and renal tuberculosis (n=21, χ(2)=4.20, P<0.05 vs. culture method; χ(2) =8.40, P<0.01 vs. smear results). The sensitivity for tuberculous meningitis had no difference among these 3 methods (n=24, P>0.05). Rifampicin-resistance of the strains from the 30 culture-positive cases of extra-pulmonary tuberculosis (20.0%, 6/30) exhibited agreement with GeneXpert MTB/RIF test.

CONCLUSION

The simplicity and high sensitivity of GeneXpert MTB/RIF technology make it a good diagnostic test for rapid detection of extra-pulmonary tuberculosis and resistance to rifampin.

Human papillomavirus infection among Uyghur women with cervical intraepithelial neoplasia in Xinjiang area

OBJECTIVE

To obtain the baseline data of Uyghur women for human papillomavirus (HPV) vaccination in Xinjiang.

MATERIALS AND METHODS

The authors analyzed the infection and distribution characteristics of HPV genotypes in genital tracts among Uyghur women with cervical intraepithelial neoplasia (CIN) in Urumqi of Xinjiang. A total of 1,431 eligible cases involved in this trial. All cervical samples from these patients were detected for HPV genotype.

RESULTS

High-risk HPV was identified in 24.7% of 979 histologically confirmed normal samples and 89.2% of 452 samples with CIN (p < 0.05). The prevalence of one single high-risk type, low-risk type, and multiple HPV types were 74.6%, 10.4%, and 4.2%, respectively. A single high risk HPV infection progressively increased with the severity of cervical lesions significantly (chi2 = 31.53, p < 0.01). While interestingly multiple infection and single low risk HPV infection were decreased with the severity of cervical lesions, and there was significant difference chi2 = 6.44, p <0.05; chi2 = 4.85, p < 0.05). The major prevalent high-risk HPV genotypes in 346 samples of CIN II-III were HPV-16, -58, -31, -33, -68,-18,-45, and -39. The comparison of HPV genotype distributions between normal cytology and CIN II-III was analyzed. The estimated risks for progression from viral infection to CIN II-III was highest in HPV-33 (prevalence ratio (PR), 2.62), followed by HPV-31 (2.27), HPV-16 (1.92), HPV-58 (1.62), HPV-18 (1.51), HPV-68 (1.05), and HPV-39 (1.05), suggesting that the six genotypes of HPV-31, -16, -58, -18, -68, and -39 (PR > 1) are higher-risk HPV types in Uyghur women with CIN in Urumqi of Xinjiang. There was no association between multiple infection and cervical lesion progression (0.31, PR < 1).

CONCLUSION

Except for the common HPV-16, -58, -31, -33, -18 in Xinjiang, HPV-68 and HPV-39 may be the oncogenic subtypes to Uyghur female with CIN in Xinjiang. Distinguishing these HPV subtypes may have implications for future cervical screening strategies and vaccine implementation. Multiple infections were not association with an increased risk of high-grade cervical neoplasia.

Post-treatment human papillomavirus status and recurrence rates in patients treated with loop electrosurgical excision procedure conization for cervical intraepithelial neoplasia

PURPOSE OF INVESTIGATION

The aim of the study was to evaluate the rate of human papillomavirus (HPV) infection clearance after loop electrosurgical excision (LEEP) procedure conization for cervical intraepithelial neoplasia (CIN) and the factors related to such clearance and to assess the relation between HPV and recurrence.

MATERIALS AND METHODS

A total 141 patients who underwent LEEP owing to high-risk human papillomavirus (HR-HPV) associated with CIN were involved this study. All patients with negative margins on LEEP specimens were followed up with HPV testing and cervical smear after three, six, nine, and 12 months post-treatment. If necessary, cervical biopsy under colposcopy was performed.

RESULTS

LEEP can effectively eliminate HPV infection. Most patients cleared HPV infection within six months. The persistent HPV infection rates were 44.6%,10.6%, 5.7%, and 2.1% after three, six, nine, and 12 months, respectively. The clearance rates were significantly slower in patients with HPV 16 infection, and not differ significantly by age, parity, and pathologic degree. Patients with persistent HR-HPV infection after treatment had a significantly higher risk for recurrence/residual after LEEP compared to patients with negative HPV infection.

CONCLUSION

The authors concluded that patients who were positive for HPV infection, especially for HPV 16, should be followed up closely after treatment.

The Mandarin Chinese shortened version of Oral Health Impact Profile for partially edentate patients with implant-supported prostheses

This study was to validate a mandarin Chinese version of Oral Health Impact Profile (OHIP-49) in China and to develop a shortened version of OHIP appropriate for use in partially dentate patients with implant-supported prostheses. The original 49 items of OHIP were translated into mandarin Chinese using a forward-backward method and administered to 580 subjects selected by stratified random sampling. Self-perceived oral health status and treatment need were also collected. Reliability and validity of the Chinese version of OHIP (OHIP-C49) were validated. A shortened version (OHIP-I) was derived from the OHIP-C49 by exploratory factor analysis (EFA) as well as expert-based approach in partially dentate patients (n=102) with implant-supported prostheses. For validation of the new modified shortened version, another independent sample of 97 partially dentate patients completed OHIP-I and their self-perceived oral health status at baseline and at least 3 months after dental implant rehabilitation. Five hundred and thirty-seven effectual questionnaires were reclaimed from the 580 subjects interviewed. Cronbach's alpha ranged from 0.78 to 0.96 and test-retest correlation coefficients ranged from 0.84 to 0.97 for subscale and summary scores. Construct validity was demonstrated by priori hypothesised associations between the OHIP-C49 scores and self-perceived oral health (P<0.001). The reliability and validity of OHIP-I were similar to which of the OHIP-C49, and the responsiveness appeared able to measure the effect of dental implant therapy effectively. The mandarin version of OHIP-49 showed sufficient psychometric properties for Chinese. The modified shortened version (OHIP-I) may be appropriate for the evaluation of implant therapy outcomes in partially dentate Chinese patients.

PTEN polymorphisms and the risk of esophageal carcinoma and gastric cardiac carcinoma in a high incidence region of China

PTEN, as a tumor suppressor gene, plays an important role in regulating cell growth, proliferation, and apoptosis. Two common polymorphisms, -9C/G and IVS4 (-/+), may alter susceptibility to the disease. To test the hypothesis that the genetic variations of PTEN play a role in the etiology of esophageal squamous cell carcinoma (ESCC) and gastric cardiac adenocarcinoma (GCA), a population-based case-control study was conducted in 350 ESCC patients, 257 GCA patients, and 634 healthy controls from a high-incidence region of Hebei province, China. The PTEN polymorphisms were genotyped by polymerase chain reaction-restriction fragment length polymorphism analysis (PCR-RFLP). The results showed that the family history of upper gastrointestinal cancer (UGIC) significantly increased the risk of developing ESCC and GCA (the age, gender and smoking status adjusted OR = 1.73 and 1.67; 95% CI = 1.29-2.32 and 1.28-2.19, respectively). The overall distribution of the PTEN -9C/G genotype was not significantly different between cancer patients and controls. Compared with the PTEN IVS4-/- genotype, the IVS4+/+ genotype significantly decreased the risk of ESCC and GCA development, the adjusted OR was 0.64 (95% CI = 0.44-0.94) and 0.63 (95% CI = 0.41-0.98), respectively. Stratification analysis by gender, age, smoking status and family history of UGIC showed that the PTEN IVS4-/+ genotype only reduced the risk of ESCC (adjusted OR = 0.55, 95%CI = 0.34-0.90) among subjects with family history of UGIC. While the IVS4+/+ genotype decreased the susceptibility to both ESCC and GCA (adjusted OR = 0.61 and 0.57, 95% CI = 0.37-0.98 and 0.34-0.98, respectively) among male subjects, the IVS4+/+ genotype only decreased the risk of ESCC development among subjects younger than 55 years (adjusted OR = 0.43, 95% CI = 0.21-0.85). In addition, the haplotype analysis found that the -9C/IVS4- haplotype increased the risk of developing ESCC and GCA (OR = 1.31 and 1.24, 95% CI = 1.08-1.58 and 1.001-1.53). Our results suggested that the PTEN IVS4+/+ homozygote may play a protective role in the development of ESCC and GCA, while the haplotype -9C/IVS4- might be the risk factor of the development of ESCC and GCA in the high incidence region population of Hebei province, China.

Extremely stable metal-encapsulated AlPb10+ and AlPb12+ clusters: mass-spectrometric discovery and density functional theory study

We report the experimental discovery of extremely stable metal-encapsulated superatom clusters of a group IVA element: AlPb+10 and AlPb+12. Ab initio density functional geometry optimizations at the B3LYP/LANL2DZ level result in a perfect icosahedron with an exceptionally large HOMO-LUMO gap of 3.1 eV for AlPb+12, and a related structure with D(4d) symmetry for AlPb+10, with a HOMO-LUMO gap of 2.6 eV. Their high stability is attributed to the reinforcing influence of the most favorable closed-packed structure and optimally filled electron shells.

The paired homeodomain protein DRG11 is required for the projection of cutaneous sensory afferent fibers to the dorsal spinal cord

Cutaneous sensory neurons that detect noxious stimuli project to the dorsal horn of the spinal cord, while those innervating muscle stretch receptors project to the ventral horn. DRG11, a paired homeodomain transcription factor, is expressed in both the developing dorsal horn and in sensory neurons, but not in the ventral spinal cord. Mouse embryos deficient in DRG11 display abnormalities in the spatio-temporal patterning of cutaneous sensory afferent fiber projections to the dorsal, but not the ventral spinal cord, as well as defects in dorsal horn morphogenesis. These early developmental abnormalities lead, in adults, to significantly attenuated sensitivity to noxious stimuli. In contrast, locomotion and sensori-motor functions appear normal. Drg11 is thus required for the formation of spatio-temporally appropriate projections from nociceptive sensory neurons to their central targets in the dorsal horn of the spinal cord.

Genetic enhancement of inflammatory pain by forebrain NR2B overexpression

N-methyl-D-aspartate (NMDA) receptors contribute to many brain functions. We studied the effect of forebrain-targeted overexpression of the NMDA receptor subunit NR2B on the response of mice to tissue injury and inflammation. Transgenic mice exhibited prominent NR2B expression and enhanced NMDA receptor-mediated synaptic responses in two pain-related forebrain areas, the anterior cingulate cortex and insular cortex, but not in the spinal cord. Although transgenic and wild type mice were indistinguishable in tests of acute pain, transgenic mice exhibited enhanced responsiveness to peripheral injection of two inflammatory stimuli, formalin and complete Freund's adjuvant. Genetic modification of forebrain NMDA receptors can therefore influence pain perception, which suggests that forebrain-selective NMDA receptor antagonists, including NR2B-selective agents, may be useful analgesics for persistent pain.

Anticonvulsant effects of gamma surgery in a model of chronic spontaneous limbic epilepsy in rats

OBJECT

The management of intractable epilepsy remains a challenge, despite advances in its surgical and nonsurgical treatment. The identification of low-risk, low-cost therapeutic strategies that lead to improved outcome is therefore an important ongoing goal of basic and clinical research. Single-dose focal ionizing beam radiation delivered at necrosis-inducing and subnecrotic levels was investigated for its effects on seizure activity by using an established model of chronic recurrent spontaneous limbic seizures in rats.

METHODS

A single 90-minute period of repetitive electrical stimulation (inducing stimulus) of the hippocampus in rats elicited a single episode of status epilepticus, followed by a 2- to 4-week seizure-free period. Spontaneous recurrent seizures developed subsequently and persisted for the duration of monitoring (2-10 months). Simultaneous computerized electroencephalography and video recording were used to monitor the animals. After the establishment of spontaneous recurrent seizures, bilateral radiation centered in the ventral hippocampal formation was administered with the Leksell gamma knife, aided by a stereotactic device custom made for small animals. A center dose of 10, 20, or 40 Gy was administered using a 4-mm collimator. Control animals were subjected to the same seizure-inducing stimulus but underwent a sham treatment instead of gamma irradiation. In a second experiment, the authors examined the effects of gamma irradiation on the proclivity of hippocampal neurons to display epileptiform discharges. Naive animals were irradiated with a single 40-Gy dose, as already described. Slices of the hippocampus were prepared from animals killed between 1 and 178 days postirradiation. Sensitivity to penicillin-induced epileptiform spiking was examined in vitro in slices prepared from control and irradiated rat brains.

CONCLUSIONS

In the first experiment, single doses of 20 or 40 Gy (but not 10 Gy) reduced substantially, and in some cases eliminated, behaviorally and electrographically recognized seizures. Significant reductions in both the frequency and duration of spontaneous seizures were observed during a follow-up period of up to 10 months postradiation. Histological examination of the targeted region did not reveal signs of necrosis. These findings indicate that single-dose focal ionizing beam irradiation at subnecrotic dosages reduces or eliminates repetitive spontaneous seizures in a rat model of temporal lobe epilepsy. In the second experiment, synaptically driven neuronal firing was shown to be intact in hippocampal neurons subjected to 40-Gy doses. However, the susceptibility to penicillin-induced epileptiform activity was reduced in the brain slices of animals receiving 40-Gy doses, compared with those from control rats that were not irradiated. The results provide rational support for the utility of subnecrotic gamma irradiation as a therapeutic strategy for treating epilepsy. These findings also provide evidence that a functional increase in the seizure threshold of hippocampal neurons contributes to the anticonvulsant influence of subnecrotic gamma irradiation.

Ischemic tolerance in the rat neocortex following hypothermic preconditioning

OBJECT

Ischemic neuronal damage associated with neurological and other types of surgery can have severe consequences for functional recovery after surgery. Hypothermia administered during and/or after ischemia has proved to be clinically beneficial and its effects often rival or exceed those of other therapeutic strategies. In the present study the authors examined whether transient hypothermia is an effective preconditioning stimulus for inducing ischemic tolerance in the brain.

METHODS

Adult rats were subjected to a 20-minute period of hypothermic preconditioning followed by an interval ranging from 6 hours to 7 days. At the end of this interval, the animals were subjected to transient focal ischemia induced by clamping one middle cerebral artery and both carotid arteries for 1 hour. The volume of cerebral infarction was assessed 1 or 7 days postischemia. In the first series of experiments, hypothermic preconditioning (28.5 degrees C) with a postconditioning interval of 1 day reduced the extent of cerebral infarction measured 1 and 7 days postischemia. In the second series, hypothermic preconditioning (31.5 degrees C) with postconditioning intervals of 6 hours, 1 day, or 2 days (but not 7 days) reduced the extent of cerebral infarction measured 1 day postischemia. Treatment with the protein synthesis inhibitor anisomycin blocked the protective effect of hypothermic preconditioning. In a final series of experiments, in vitro brain slices prepared from hypothermia-preconditioned (nonischemic) animals were shown to tolerate a hypoxic challenge better than slices prepared from unconditioned animals.

CONCLUSIONS

These findings indicate that hypothermic preconditioning induces a form of delayed tolerance to focal ischemic damage. The time course over which tolerance occurs and the ability of a protein synthesis inhibitor to block tolerance suggest that increased expression of one or more gene products is necessary to establish tissue tolerance following hypothermia. The attenuation of hypoxic injury in vitro following in vivo preconditioning indicates that tolerance is due, at least in part, to direct effects on the brain neuropil. Hypothermic preconditioning could provide a relatively low-risk approach for improving surgical outcome after invasive surgery, including high-risk neurological and cardiovascular procedures.

Genetic ablation of parathyroid glands reveals another source of parathyroid hormone

The parathyroid glands are the only known source of circulating parathyroid hormone (PTH), which initiates an endocrine cascade that regulates serum calcium concentration. Glial cells missing2 (Gcm2), a mouse homologue of Drosophila Gcm, is the only transcription factor whose expression is restricted to the parathyroid glands. Here we show that Gcm2-deficient mice lack parathyroid glands and exhibit a biological hypoparathyroidism, identifying Gcm2 as a master regulatory gene of parathyroid gland development. Unlike PTH receptor-deficient mice, however, Gcm2-deficient mice are viable and fertile, and have only a mildly abnormal bone phenotype. Despite their lack of parathyroid glands, Gcm2-deficient mice have PTH serum levels identical to those of wild-type mice, as do parathyroidectomized wild-type animals. Expression and ablation studies identified the thymus, where Gcm1, another Gcm homologue, is expressed, as the additional, downregulatable source of PTH. Thus, Gcm2 deletion uncovers an auxiliary mechanism for the regulation of calcium homeostasis in the absence of parathyroid glands. We propose that this backup mechanism may be a general feature of endocrine regulation.

Distribution and initiation of seizure activity in a rat brain with subcortical band heterotopia

PURPOSE

Misplaced (heterotopic) cortical neurons are a common feature of developmental epilepsies. To better understand seizure disorders associated with cortical heterotopia, the sites of aberrant discharge activity were investigated in vivo and in vitro in a seizure-prone mutant rat (tish) exhibiting subcortical band heterotopia.

METHODS

Depth electrode recordings and postmortem assessment of regional c-fos mRNA levels were used to characterize the distribution of aberrant discharge activity during spontaneous seizures in vivo. Electrophysiologic recordings of spontaneous and evoked activity also were performed by using in vitro brain slices from the tish rat treated with proconvulsant drugs (penicillin and 4-aminopyridine).

RESULTS

Depth electrode recordings demonstrate that seizure activity begins almost simultaneously in the normotopic and heterotopic areas of the tish neocortex. Spontaneous seizures induce c-fos mRNA in normotopic and heterotopic neocortical areas, and limbic regions. The threshold concentrations of proconvulsant drugs for inducing epileptiform spiking were similar in the normotopic and heterotopic areas of tish brain slices. Manipulations that blocked communication between the normotopic and heterotopic areas of the cortex inhibited spiking in the heterotopic, but not the normotopic, area of the cortex.

CONCLUSIONS

These findings indicate that aberrant discharge activity occurs in normotopic and heterotopic areas of the neocortex, and in certain limbic regions during spontaneous seizures in the tish rat. Normotopic neurons are more prone to exhibit epileptiform activity than are heterotopic neurons in the tish cortex, and heterotopic neurons are recruited into spiking by activity initiated in normotopic neurons. The findings indicate that seizures in the tish brain primarily involve telencephalic structures, and suggest that normotopic neurons are responsible for initiating seizures in the dysplastic neocortex.

Hypothermia-induced ischemic tolerance

Delayed resistance to ischemic injury can be induced by a variety of conditioning stimuli. This phenomenon, known as delayed ischemic tolerance, is initiated over several hours or a day, and can persist for up to a week or more. The present paper describes recent experiments in which transient hypothermia was used as a conditioning stimulus to induce ischemic tolerance. A brief period of hypothermia administered 6 to 48 hours prior to focal ischemia reduces subsequent cerebral infarction. Hypothermia-induced ischemic tolerance is reversed by 7 days postconditioning, and is blocked by the protein synthesis inhibitor anisomycin. Electrophysiological studies utilizing in vitro brain slices demonstrate that hypoxic damage to synaptic responses is reduced in slices prepared from hypothermia-preconditioned animals. Taken together, these findings indicate that transient hypothermia induces tolerance in the brain parenchyma, and that increased expression of one or more gene products contributes to this phenomenon. Inasmuch as hypothermia is already an approved clinical procedure for intraischemic and postischemic therapy, it is possible that hypothermia could provide a clinically useful conditioning stimulus for limiting injury elicited by anticipated periods of ischemia.

Symmetrical mutant phenotypes of the receptor EphB4 and its specific transmembrane ligand ephrin-B2 in cardiovascular development

Ephrin-B2 is a transmembrane ligand that is specifically expressed on arteries but not veins and that is essential for cardiovascular development. However, ephrin-B2 is also expressed in nonvascular tissues and interacts with multiple EphB class receptors expressed in both endothelial and nonendothelial cell types. Thus, the identity of the relevant receptor for ephrin-B2 and the site(s) where these molecules interact to control angiogenesis were not clear. Here we show that EphB4, a specific receptor for ephrin-B2, is exclusively expressed by vascular endothelial cells in embryos and is preferentially expressed on veins. A targeted mutation in EphB4 essentially phenocopies the mutation in ephrin-B2. These data indicate that ephrin-B2-EphB4 interactions are intrinsically required in vascular endothelial cells and are consistent with the idea that they mediate bidirectional signaling essential for angiogenesis.

NRSF/REST is required in vivo for repression of multiple neuronal target genes during embryogenesis

The neuron-restrictive silencer factor NRSF (also known as REST and XBR) can silence transcription from neuronal promoters in non-neuronal cell lines, but its function during normal development is unknown. In mice, a targeted mutation of Rest, the gene encoding NRSF, caused derepression of neuron-specific tubulin in a subset of non-neural tissues and embryonic lethality. Mosaic inhibition of NRSF in chicken embryos, using a dominant-negative form of NRSF, also caused derepression of neuronal tubulin, as well as of several other neuronal target genes, in both non-neural tissues and central nervous system neuronal progenitors. These results indicate that NRSF is required to repress neuronal gene expression in vivo, in both extra-neural and undifferentiated neural tissue.

Molecular distinction and angiogenic interaction between embryonic arteries and veins revealed by ephrin-B2 and its receptor Eph-B4

The vertebrate circulatory system is composed of arteries and veins. The functional and pathological differences between these vessels have been assumed to reflect physiological differences such as oxygenation and blood pressure. Here we show that ephrin-B2, an Eph family transmembrane ligand, marks arterial but not venous endothelial cells from the onset of angiogenesis. Conversely, Eph-B4, a receptor for ephrin-B2, marks veins but not arteries. ephrin-B2 knockout mice display defects in angiogenesis by both arteries and veins in the capillary networks of the head and yolk sac as well as in myocardial trabeculation. These results provide evidence that differences between arteries and veins are in part genetically determined and suggest that reciprocal signaling between these two types of vessels is crucial for morphogenesis of the capillary beds.

[A new way for neural transplantation: the grafted central neurons migration from the subarachnoid space into the spinal cord and cerebral cortex]

In the studies of neural transplantation, Chen and his colleagues observed that the grafted central neurons could migrate from the subarachnoid space into the spinal cord and cerebral cortex. This finding promises an attractive possibility that a lot of neurons might be introduced into a long distance of the spinal cord and the extensive superficial layer of the brain which has suffered neuronal loss and thus might reinnervate a wide range of denervated area. Female rats were used in the study. Neural tissues or cell suspension containing fetal monoaminergic or arginine vasopressin (AVP) neurons were implanted into the subarachnoid space of the transected spinal cord or the normal brain and spinal cord. The rats were treated in different ways: some were grafted and the spinal cord was cut at the same time; grafted one month later or before the spinal cord was cut; grafted but the brain and spinal cord remained intact. Immunohistochemical method was used to monitor the grafted neurons after these rats survived for one or nine months. The results showed that there were a few to hundreds of 5-HT, TH or AVP-immunoreactive neurons and fibers found in the spinal cord or cerebral cortex near the grafted region. These neurons grew well and displayed their capacity of adaptability and long-time survival in the host CNS. No neurons, however, were found in the subarachnoid space of the grafted rats which had survived for another month or longer. On the other side, grafted with tissue block, it was found that transplants left in the grafted region grew as a "nodule" attaching to the surface of the spinal cord. The "nodule" was also found occasionally when the cell suspension was centered heavily at one region of the subarachnoid space. In both cases, the pia mater between them disappeared. Immunoreactive neurons were found in the "nodule" and neighboring spinal cord, some fibers from the neurons in the "nodule" extended into the spinal cord. It is supposed that a part of cells in the suspension died after grafted in the subarachnoid space and released hydrolases which injured the near pia mater by hydrolysis. As a result, some neurons in the suspension had a chance to migrate into the spinal cord and cerebral cortex. After the transplant in the subarachnoid space was gradually cleaned out, the enzymatic hydrolysis to the pia mater became weaker and finally stopped, the lesioned pia mater was gradually repaired. If the transplant was not cleared timely, the pia mater could not withstand the persistent hydrolysis and collapsed finally, leading the transplant to be fused with the host CNS.

Design and construction of a long-term continuous video-EEG monitoring unit for simultaneous recording of multiple small animals

In recent years several new rat models of human limbic/mesial temporal lobe epilepsy have been described [1,2,4-7,11,15-17]. Unlike earlier models such as kindling in which the seizures are induced by an exogenous stimulus, these new models are characterized by seizures that occur spontaneously at random intervals. Although the spontaneity of the seizures makes these models more like human epilepsy, documentation of these seizures by direct observation is highly inefficient, and sub-behavioral electrographic seizures could be missed. Continuous paper EEG and video recording have been used [5-7,15], but these techniques are resource intensive. The slow paper speed required by long-term paper recordings limits the ability to differentiate between true seizure activity and electrical artifact. Subtle behavioral seizures are likely to be missed during rapid review of video recordings alone [16]. Ambulatory cassette EEG recordings have been used [3], but the systems require expensive proprietary hardware, and the systems have limited channels for recording (8-16). To improve the utility of the models, we developed a long-term EEG/video monitoring system to detect the electrographic seizures and document their behavioral accompaniment. The system is based on commercially available components, including a computerized EEG seizure detection system that was initially developed for human seizure monitoring [8,9,13]. Seizures are reliably detected and the data are reduced so that 24 h of recording can be reviewed in 30-90 min. Although the computer program is accurate, special care must be taken in system design and construction to reduce sources of electrical artifact that can cause false detections when multiple animals are recorded simultaneously on a single EEG machine. During data review it is necessary to differentiate between electrical artifact induced by animal activity from true seizure activity by key EEG patterns. Certain seizure patterns (less than 3 hz. low amplitude) will not be detected by the seizure detection program, but the system is highly effective for typical limbic seizures and may be useful for the animal models of absence epilepsy [12,14]. It can also be used as a continuous or intermittent EEG/physiological recording device for experiments that examine animals' spontaneous behavior and the EEG correlate (e.g. sleep/wake cycles, learning and memory tasks).

Neuronal recovery after moderate hypoxia is improved by the calpain inhibitor MDL28170

The role of calcium-activated proteolysis in hypoxic neuronal injury was investigated using an in vitro slice model of moderate hypoxia that mimics many features of an ischemic penumbra. The calpain inhibitor, MDL28170, significantly improved the recovery of synaptic responses in hippocampal slices following prolonged, moderate hypoxia without hypoxic depolarization. This finding further implicates calpain-mediated proteolysis in the development of neuronal injury following moderate metabolic challenge such as occurs in regions of partial ischemia.

A genetic animal model of human neocortical heterotopia associated with seizures

Malformations of the human neocortex are commonly associated with developmental delays, mental retardation, and epilepsy. This study describes a novel neurologically mutant rat exhibiting a forebrain anomaly resembling the human neuronal migration disorder of double cortex. This mutant displays a telencephalic internal structural heterotopia (tish) that is inherited in an autosomal recessive manner. The bilateral heterotopia is prominent below the frontal and parietal neocortices but is rarely observed in temporal neocortex. Neurons in the heterotopia exhibit neocortical-like morphologies and send typical projections to subcortical sites; however, characteristic lamination and radial orientation are disturbed in the heterotopia. The period of neurogenesis during which cells in the heterotopia are generated is the same as in the normotopic neocortex; however, the cells in the heterotopia exhibit a "rim-to-core" neurogenetic pattern rather than the characteristic "inside-out" pattern observed in normotopic neocortex. Similar to the human syndrome of double cortex, some of the animals with the tish phenotype exhibit spontaneous recurrent electrographic and behavioral seizures. The tish rat is a unique neurological mutant that shares several features with a human cortical malformation associated with epilepsy. On the basis of its regional connectivity, histological composition, and period of neurogenesis, the heterotopic region in the tish rat is neocortical in nature. This neurological mutant represents a novel model system for investigating mechanisms of aberrant neocortical development and is likely to provide insights into the cellular and molecular events contributing to seizure development in dysplastic neocortex.

Hypoxic neuronal damage in the absence of hypoxic depolarization in rat hippocampal slices: the role of glutamate receptors

The propensity of neurons to undergo profound and precipitous depolarization is believed to contribute to their characteristic vulnerability to hypoxic injury. The length of time a neuron spends in a depolarized state following hypoxic depolarization (HD) is a critical determinant of the extent of irreversible cell damage. It is less clear, however, what the effects of moderate hypoxia are when HD does not occur. The present study examined the effects of prolonged, moderate hypoxia which does not elicit HD in rat hippocampal slices. Extracellularly-recorded population excitatory postsynaptic potentials (pEPSPs) in stratum radiatum of CA1 were eliminated 10-15 min after initiating hypoxia. Physiological damage was related to the hypoxic duration: full, intermediate, or poor recovery of pEPSP slope was observed after 30, 60, or 120 min of hypoxia, respectively. The glutamate receptor antagonists, D,L-2-amino-5-phosphonovaleric acid (APV) or 6,7-dinitroquinoxaline-2,3-dione (DNQX), enhanced the post-hypoxic recovery of synaptic responses. These findings demonstrate that profound HD is not necessary to elicit physiological damage during moderate hypoxia; moreover, the neuroprotective actions of excitatory transmitter antagonists are not limited to their capacity to delay HD. The precise characterization of cellular responses under these conditions will be of particular importance for understanding the pathophysiology of an ischemic penumbra.

twist is required in head mesenchyme for cranial neural tube morphogenesis

To understand the role of twist during mammalian development, we generated twist-null mice. twist-null embryos died at embryonic day 11.5. Their most prominent phenotype was a failure of the cranial neural folds to fuse. Mutant embryos also had defects in head mesenchyme, somites, and limb buds. Chimera analysis suggested that head mesenchyme was required for cranial neural tube closure and that twist acted in a cell-autonomous manner in this tissue. In addition, in the head mesenchyme region of chimeras, twist-null cells were segregated from wild-type cells, and in the forebrain they lacked mesenchymal characteristics. These results suggest that twist regulates the cellular phenotype and behavior of head mesenchyme cells that are essential for the subsequent formation of the cranial neural tube.

[Autoradiographic approach to the developmental study on the binding sites of AVP4-8 in rat hippocampus]

The localization of the 35S-labelled AVP4-8 binding sites in the rat hippocampus was studied by using autoradiographic approach via observing the selective damages of hippocampal neurons by neurotoxins, and the developmental regulation of the hippocampal AVP4-8 receptor by pretreatment with exogenous AVP4-8 was observed. In adult rat hippocampus, the binding sites of AVP4-8 were assembled on the whole hippocampal pyramidal cell layer and granular cell layer of the dentate gyrus. Treatment of colchicine caused parallel disappearances of granular cells and the AVP4-8 binding sites in the gyrus, while treatment of kaininc acid destroyed the CA3-CA4 pyramidal cell layer and abolished the binding sites in this area. The developmental emergences of AVP4-8 binding sites were normally on postnatal day 6 in pyramidal cell layer and postnatal day 7 in the dentate gyrus. However, postnatal daily treatments of exogenous AVP4-8 enhanced the formations of both pyramidal and dentate binding sites, as they appeared rather densely on postnatal day 5. The characterized distribution of AVP4-8 binding sites in the rat hippocampus and the relationship between their developmental enhancements and facilitation of learning behaviors in mature rat by neonatal treatment of exogenous AVP4-8 were discussed.

[A study of transpial migration of implanted serotonergic neurons in rat spinal cord]

Transpial migration of implanted 5-HT neurons from the subarachnoid space into the spinal cord was studied in adult Wistar rats. Embryonic raphe tissue or cell suspension containing 5-HT cells was used as grafts. The implanted 5-HT cells were monitored by 5-HT immunohistochemical method. The results are as follows: (1) 10 d after cutting the spinal cord at lower thoracic level, 5-HT fibers disappeared in the transected spinal cord. (2) Raphe tissue was implanted into the subarachnoid space of the thoracic lumbar segment after the spinal cord was cut. One month later, 5-HT positive cells could be found in the transected spinal cord with fibers extending into both the grey and the white matters. (3) If the raphe cell suspension instead was implanted, a number of 5-HT positive cells appeared in the grey matter near the implanted region and the distribution of these cells in the grey matter was quite consistent with the implanted range of the cell suspension in the subarachnoid space. The 5-HT positive cells which had entered into the spinal cord sent out fibers and reestablished a new fiber network in the grey matter. (4) After implantation, the number of the 5-HT positive fibers in the transected grey matter became more and more sparsely distributed with increasing distance from the cell bodies and the 5-HT positive fibers reappeared in the white matter were much less than that in the grey matter. Present results show that the implanted 5-HT neurons are able to migrate transpially from the subarachnoid space into the spinal cord.

[Guiding effect of embryonic fimbria graft on cholinergic fiber growth in hippocampus of adult rats]

In view of the fact that in embryonic and neonatal central nervous system (CNS), the pathway of developing fiber tracts is capable of guiding the axonal growth, it would be interesting to know whether a similar effect exists on the axonal growth in adult CNS. Embryonic fimbria was grafted into the hippocampus of the adult rat. Two weeks later, the grafts were examined for cholinergic fibers with AChE histochemical method. It was found that a lot of cholinergic fibers appeared in the embryonic graft, but none of them in the adult fimbria graft as control. If the fimbria-fornix was transected at the time of grafting, no cholinergic fibers could subsequently be detected in both the embryonic graft and the host hippocampus. If a suspension of embryonic fimbria was used as a graft, only a few of long cholinergic fibers could be found in the grafted area. However, if tissue fragments of embryonic fimbria adhered to a strip of nitrocellulose filter were grafted as previously, numerous cholinergic fibers from the host hippocampus were found to be attracted around the strip and grow along the surface of the filter. The results seem to indicate that grafted embryonic fimbria or its tissue fragments are able to guide cholinergic fiber growth in adult hippocampus. It is possible that embryonic fimbria and other pathways of developing CNS fiber tracts provide a natural substrate for guiding axonal growth in adult CNS.

[Surgical treatment of congenital horseshoe kidney. Report of 21 cases]

From 1984 to 1989, we treated surgically 21 patients with horseshoe kidney. Clinically, urinary tract calculi was a common problem. In this group, 14 patients were complicated by urinary tract calculi. Diagnosis of horseshoe kidney was established roentgenographically in most cases. Twenty-one patients underwent 25 operative procedures for removal of the urinary tract stone and division of the isthmus. Eight operations were performed by classical extraperitoneal horizontal flank incision and 17 were done transperitoneally. We consider that the latter is more superior than the former.

[Gluteus maximus myocutaneous flap in the repair of sacral and gluteal decubitus ulcers]

16 cases of decubitus ulcers in the sacral, ischiadic and great trochanter regions were treated with rotating myocutaneous flap of the caudal portion of the gluteus maximus from 1983 to 1989. They were followed up for 3 to 68 months, with the exception of 4 patients. The results were excellent. 30 gluteus regions were studied in 15 cadavers. It was found that the caudal 3/4 of the gluteus maximus muscle was supplied by the inferior gluteal artery, and a flap measuring 12.9 x 9.7 cm could be formed therein with easy dissection. The flap tolerates pressure well. Unilateral flap is adequate to cover a decubitus ulcer within a diameter of 10cm, while bilateral flaps are necessary for a larger ulcer.

The effects of octopamine on juvenile hormone biosynthesis, electrophysiology, and cAMP content of the corpora allata of the cockroach Diploptera punctata

Juvenile hormone production by the corpora allata of the adult female cockroach, Diploptera punctata, can be modulated by treatment with the biogenic amine, octopamine. Endogenous octopamine has been identified within the CA, using HPLC and electrochemical detection. Treatment with octopamine results in a sinusoidal, dose-dependent inhibition of JH biosynthesis by CA from day 2 virgin females, with maximal inhibition occurring at 10(-10) M and 10(-4 M. In day 4 and day 8 mated female corpora allata octopamine inhibited JH biosynthesis at 5 x 10(-5) M. Although the elevation of either cAMP or cGMP within the CA is known to be associated with an inhibition of JH biosynthesis, treatment with high concentrations of octopamine results in an increase in the level of cAMP but not cGMP. This effect is both dose- and time-dependent. Octopamine treatment also initiates changes in the passive membrane responses of the CA. Superfusion of CA with octopamine results in a pronounced hyperpolarization of CA cells and an increase in the electrotonic potential (indicative of the degree of electrical coupling between CA cells). This effect could be blocked by the octopamine receptor blocker phentolamine. Treatment with octopamine or phentolamine also blocked the hyperpolarization of CA cells normally associated with electrical stimulation of the axon tracts innervating the CA. We hypothesize that octopamine may be a natural neuromodulator of JH production by CA, regulating ion channels in CA cells themselves as well as release of the inhibitory neuropeptide, allatostatin, from the terminals within the CA.

Effects of diuretic treatment and of dietary sodium on renal binding of 3H-metolazone

We report a series of experiments designed to determine if agents and conditions that have been reported to alter sodium reabsorption, Na-K-ATPase activity or cellular structure in the rat distal nephron might also regulate the density or affinity of binding of 3H-metolazone to the putative thiazide receptor in the distal nephron. Experimental conditions selected for study were acute (60-min) and chronic hydrochlorothiazide (HCTZ), acute acetazolamide, acute and chronic furosemide, and 14 days of varied intake of dietary sodium. The density of the binding of 3H-metolazone was increased 47% by acute HCTZ (P less than 0.001) and 39% (P less than 0.001) by acute furosemide. In contrast, acute acetazolamide produced no change in binding despite eliciting a dramatic diuresis. Chronic HCTZ (5 days) and chronic furosemide (7 days) increased binding of 3H-metolazone by 46% (P less than 0.001) and by 101% (P less than 0.001), respectively. Variation of dietary sodium intake over a range that allowed normal growth of the animal and that produced urinary excretion of Na varying from 0.28 to 2.62 mEq/100 g/day failed to alter the density of binding of 3H-metolazone. These studies are the first indication that the density of the thiazide receptor is regulated by a variety of both acute and chronic conditions that have previously been associated with changes in transport, ultrastructure or Na-K-ATPase activity in the distal nephron.(ABSTRACT TRUNCATED AT 250 WORDS)

A new type II restriction endonuclease, BsmA I, from Bacillus stearothermophilus

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Isolation and characterization of restriction endonuclease BstYI from Bacillus stearothermophilus Y406

BstYI, an isoschizomer of XhoII and MflI, has been purified from Bacillus stearothermophilus Y406. This enzyme recognized 5'...Pu/GATCPy...3' in DNA and cleaved between Pu and G in this sequence. BstYI can be easily isolated and purified by heparin-agarose column chromatography in a high yield (8000 units BstYI can be obtained per g wet wt of cells).

Neonatal administrations of a vasopressin analog (DDAVP) and hypertonic saline enhance learning behavior in rats

Groups of newborn Wistar rats received daily 1-desamino-8-D-arginine-vasopressin (DDAVP), oxytocin (OXT), hypertonic saline or normal saline for 14 days from day 1 to day 14 of life. One or three months later they were trained in a maze for brightness discrimination (BD). A group of untreated adult male rats received posttrial DDAVP or normal saline for brightness discrimination. Subsequently all the retentions of BD were tested after one month. We found that the neonatal treatments with both DDAVP and hypertonic saline facilitated acquisition and subsequent maintenance of brightness discrimination in immature and mature rats, and also that posttreatment with DDAVP enhanced retention of BD in adult rats. Oxytocin and normal saline had no effect on these parameters. The results are interpreted as showing that endogenous AVP and its synthetic analog enhance the development and adult function of central neural substrates involved in learning behaviors.

Isolation and identification of restriction endonuclease BstF I

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Genetic analysis of Bacillus stearothermophilus by protoplast fusion

Efficient and reliable protoplasting, regeneration, and fusion techniques were established for the prototrophic strain Bacillus stearothermophilus NUB36. Auxotrophic mutants were isolated, and protoplast fusion was used to construct isogenic mutant strains and for chromosomal mapping. Markers were mapped using two-, three-, and four-factor crosses. The order of the markers was hom-1-thr-1-his-1-(gly-1 or gly-2)-pur-1-pur-2. These markers may be analogous to hom, thrA, hisA, glyC, and purA markers on the Bacillus subtilis chromosome. No analogous pur-1 marker has been reported in B. subtilis. The relative order of three of the markers (hom-1-thr-1-gly-1) was independently confirmed by transduction.