Long term growth factor exposure and differential tyrosine phosphorylation are required for DNA synthesis in BALB/c 3T3 cells

The importance of growth factor-mediated immediate-early cellular events to the cell cycle has influenced the development and identity of oncogenes and tumor suppressor genes as well as the concept that growth factors commit mammalian cells to enter a biochemical program that ultimately yields DNA synthesis. However, the mid and late events involved in the regulation of growth factor-induced signal transduction remain largely unknown. In this report we demonstrate that BALB/c 3T3 cells require continuous exposure to fibroblast growth factor (FGF)-1 for a minimum of 12 h to achieve near maximal DNA synthesis. This correlates with the continuous internalization of radiolabeled FGF-1 into the cytosol and nucleus of BALB/c 3T3 cells and the maintenance of a low level of FGF receptors on the cell surface during the entire G1 phase of the cell cycle. Further analysis demonstrates the maintenance of a continuous series of differential FGF-1-induced tyrosine phosphorylation events including the phosphorylation of phospholipase C-gamma as well as novel FGF receptor polypeptide substrates, p60, p85, p90, and p130 throughout the G1 phase of the BALB/c 3T3 cell cycle. The tyrosine phosphorylation events are biphasic during the 12-h period after the administration of FGF-1, and the second phase is characterized by hyper-tyrosine phosphorylation of p60, p85, and p130. Interestingly, NIH 3T3 cells which overexpress the FGF receptor-1 polypeptide demonstrate exaggerated tyrosine phosphorylation of p60 and p85 but not p90 and exhibit growth factor-independent cell proliferation. These results suggest that the initiation of DNA synthesis in BALB/c 3T3 cells by FGF-1 is regulated by a complex biochemical program that involves the continuous tyrosine phosphorylation of known and novel polypeptides throughout the G0 to G1 transition period of the cell cycle.

Application of an event marker in the occupational epidemiologic study of acute irritant symptoms

Field studies of occupational exposure to airborne irritants have predominantly relied on symptom surveys of study participants. As part of a new approach to the study of acute irritant symptoms, subjects exposed to sodium borate dusts recorded their symptom responses at hourly interviews as well as instantaneously on an electronic device called an event marker. Overall, the unprompted marks indicated fewer irritant events than the interviews. Marks were more frequent in the presence of more than one type of symptom and also appeared to reflect more severe symptoms. A proportion of the marked events occurred in time intervals when no symptoms were recalled during the interview. The exposure-response relations were similar regardless of whether they were based on the interview reports or the electronically marked symptoms. The event marker provided a means to examine the time of onset of the acute symptom event. It also made it possible to examine directly the timing profiles of symptom response in relation to changes in exposure levels in a field setting. Despite some inconsistencies, the finding suggests that the event marker may provide an alternative to frequent interviews of exposed workers to obtain irritant symptom responses for exposure-response modeling.

Parental attitudes toward legislation for helmet use by child cyclists

A random-digit dialing telephone survey was conducted in the second half of 1991 to examine parental attitudes toward legislation of helmet use by child cyclists. The surveyed population were 703 parents of at least one child aged 5-17 years who owned a bicycle and lived within Metropolitan Toronto. Five hundred sixty-eight (80.8%) responding parents were in favour of the suggested legislation, 81 (11.5%) were against, and 54 (7.7%) had no opinion on the issue. The 95% confidence interval for the support rate was 78.9-83.7%. Although there was some variation in the level of support, at least two thirds of the respondents in every subgroup, except parents with teenaged children (aged 15-17 years), were in favour of the legislation. Legislation requiring bicycle helmet use by all children has strong support from the public. Additional surveys should be directed at public attitudes to legislation of helmet use by adults.

Home injuries to children

To describe the circumstances around childhood injuries in the home, information on home injuries to children was collected in the emergency room of a pediatric trauma centre as part of an injury surveillance program. During a one-year period, data on 1,538 patients (age < or = 18 years) injured at home were recorded. An inverse s-shape association of home injuries with age was observed. Falls were the leading cause (51%); other children were struck by objects (18%) or sustained cutting/piercing injuries (9%). Age was positively associated with the likelihood of being struck by objects, cutting/piercing, and overexertion, but negatively associated with falls. Playing was the most common activity at time of injury. The peak time of injuries tended to be the early evening. Because most injuries occurred in an environment that seemed safe to parents, reduction in home injuries may require identification of potential hazards in the context of the stages of children's psychological and motor development.

Evaluation of a promotional strategy to increase bicycle helmet use by children

Bicycle-related head injuries are an important cause of death and disability, despite the availability of helmets. The objective of this study was to evaluate the effectiveness of a school-based bicycle helmet promotion program in increasing helmet use by children while controlling for secular trends. Two high-income and two low-income schools in an urban Canadian community were selected to receive a bicycle helmet promotion intervention, with the remaining 18 schools serving as controls. Approximately 1800 observations of bicycling children were made at randomly selected observational sites 2 to 5 months after the intervention to assess changes in behavior. Helmet use at all observation sites tripled from 3.4% (1990, preintervention) to 16% (1991, postintervention). In the high-income intervention area, observed helmet use rose dramatically from 4% to 36% in contrast to the more modest increase in the high-income control area from 4% to 15%. In the low-income intervention area, there was a modest increase from 1% to 7%, but it did not differ from the increase in the low-income control area from 3% to 13%. The program was highly successful in children of high-income families but not in children of low-income families. Developing strategies for low-income families remains a priority.

A robust algorithm for reduction of truncation artifact in chemical shift images

A new iterative technique to reduce the ringing artifacts in chemical shift images due to the truncation of the high spatial frequency is presented. In this approach the authors extrapolate the high spatial frequency data guided by the edge information obtained from a high resolution anatomic image of the region of interest. The fact that the edge information obtained from the anatomic image can be off by a few pixels (due to factors such as chemical shift artifact, error in edge detection or misregistration) is taken into account by assuming a confidence interval of several pixels around the anatomic edges. The algorithm is validated on simulated and in vivo data, and excellent results were obtained.

SLIM revisited

SLIM (spectroscopic localization by imaging), a tool for in vivo magnetic resonance spectroscopy that provides compartmental spectra from relatively few phase-encoded data, is limited by the inhomogeneities within each compartment. It is shown that the SLIM-derived spectra approach the average compartmental spectra as the number of phase encoded data approaches infinity, and the convergent rate of the error for each compartment is proportional to the size of the compartment. Numerical simulation studies are conducted to confirm the convergence property. A detailed discussion of the result is provided.

Computerized plotting of low skin impedance points

The distribution of low skin impedance points (LSIP) was studied on 68 subjects with a computer system designed for the measurement of skin impedance. The results demonstrated that LSIPs were basically distributed along the 14 channels, the overwhelming majority located right on or within 5 mm bilaterally to their courses. LSIPs were found in the area between every two channels only in a few cases. Moreover, there was no marked natural fluctuation of skin impedance in the human body and the distribution of LSIPs was considerably stable, which could be plotted on any day in the experiment. It is clear that such particular distribution of LSIPs along channels was really a biological phenomenon, not an experimental error. However, the distribution of low skin impedance was not an uninterrupted solid line but a series of LSIPs basically along the channel course. The method used in this work was accurate, reliable and repeatable which has upgraded the measurement of LSIPs to a new level. Under certain conditions, skin impedance can be used as an objective index in channel research.

Clonal and antigenic analysis of serogroup A Neisseria meningitidis with particular reference to epidemiological features of epidemic meningitis in the People's Republic of China

Representative strains of serogroup A Neisseria meningitidis were chosen from all major meningitis epidemics worldwide since 1960 and subjected to analysis for the electrophoretic variation of 15 cytoplasmic allozymes and four outer membrane proteins. The 290 strains defined 84 unique electrophoretic types which were classified in nine subgroups. Tests with monoclonal antibodies specific for conserved pilin epitopes showed that the class I, IIa, and IIb epitopes were uniform within the subgroups. Similarly, the subgroups were uniform for expression of different variable regions of class 1 outer membrane protein, with a few minor exceptions. Many of the bacteria tested were isolated in the People's Republic of China, and the epidemiology of Chinese epidemics of meningococcal meningitis is described. The analysis approaches a global description of epidemic meningitis caused by serogroup A meningococci in the past 30 years.

Analysis of endogenous and exogenous nuclear translocation of fibroblast growth factor-1 in NIH 3T3 cells

Nuclear localization of fibroblast growth factors (FGF) have been reported by many laboratories. We demonstrate here that FGF-1, the precursor for acidic FGF contains a putative nuclear translocation sequence (NTS) NYKKPKL, which is able to direct the expression of the bacterial beta galactosidase (beta gal) gene to the nucleus of transfected NIH 3T3 cells. However, this NTS is unable to target either FGF-1 itself or a FGF-1-beta gal fusion protein into the nucleus, suggesting that FGF-1 may contain an additional sequence which prevents endogenously expressed FGF-1 from being translocated into the nucleus. Indeed, when FGF-1 was fused to the NTS derived from the yeast histone 2B gene, the chimeric construct also failed to be transported into the nucleus either by itself or as a beta gal fusion protein. Interestingly, when 125I-FGF-1 was used to stimulate quiescent NIH 3T3 cells, a significant amount of internalized 125I-FGF-1 (approximately 10%) was found within the nucleus and the nuclear localization of FGF-1 through the exogenous pathway could be significantly reduced by suramin, an inhibitor of the interaction of FGF-1 with its receptor. These data suggest that while FGF-1 contains a NTS, nuclear translocation requires an exogenous and not an endogenous pathway.

[Pharmacokinetics of liensinine in rabbits]

A method for the determination of plasma concentration of liensinine with HPLC and pharmacokinetic study of liensinine in rabbits were reported. Assay linearity was shown over the range of 0.125-2.5 micrograms/ml serum with regression coefficient of 0.9997. The mean recoveries of liensinine in plasma (within-day and between-days) were all more than 99% of the dose and the coefficients of variation were less than 5%. After a single intravenous injection of liensinine 6mg/kg to rabbit. The pharmacokinetic characteristics were found to fit a two-compartment open model. Important parameters were: t1/2 alpha = 8.303 min t1/2 beta = 129.960min AUC = 132.67 micrograms.min/ml CL = 0.045 L/min Vc = 2.768 L/kg.

Dose related acute irritant symptom responses to occupational exposure to sodium borate dusts

A repeated measurement design was employed in the study of acute symptoms of eye and respiratory tract irritation resulting from occupational exposure to sodium borate dusts. The symptom assessment of the 79 exposed and 27 unexposed subjects comprised interviews before the shift began and then at regular hourly intervals for the next six hours of the shift, four days in a row. Exposures were monitored concurrently with a personal real time aerosol monitor. Two different exposure profiles, a daily average and short term (15 minute) average, were used in the analysis. Exposure-response relations were evaluated by linking incidence rates for each symptom with categories of exposure. Acute incidence rates for nasal, eye, and throat irritation, and coughing and breathlessness were found to be associated with increased exposure levels of both exposure indices. Steeper exposure-response slopes were seen when short term exposure concentrations were used. Results from multivariate logistic regression analysis suggest that current smokers tended to be less sensitive to the exposure to airborne sodium borate dust. There was no indication that anhydrous sodium borate was more potent than the other sodium borates in this work environment.

Retrospective fusion of radiographic and MR data for localization of subdural electrodes

Prior to epilepsy surgery, subdural electrodes are often implanted and monitored for a few days to identify the focus of abnormal electrical activity. During the implantation and subsequent brain resection, there may be uncertainty about the exact location of the electrodes with respect to features of brain anatomy such as specific gyral convolutions or lesions. In experiments with a phantom and patients, implanted electrodes were imaged with multiplanar skull radiographs (or CT scans). After retrospective registration with preimplantation MR data, the electrodes were mapped from these studies onto an MR-derived three-dimensional brain model. The resulting multimodality displays showed the relationship of the electrodes to brain anatomy. In one patient the position of each electrode with respect to a metabolic lesion was also displayed by mapping preimplantation PET data onto the same brain model. This new display of electrode positions may strengthen the interpretation of subdural electrical recordings and thereby reduce uncertainty in planning the resection of epileptic tissue.

Detection of circulating antigen by McAb-AST for evaluating the efficacy of anti-Leishmania chemotherapy

We have adapted the simple and sensitive McAb-antigen spot test (AST) for evaluating the efficacy of anti-Leishmania chemotherapy. Serum samples from 37 kala-azar patients were tested by McAb-AST, and all showed definite positive reactions before treatment. After a course of antimony treatment, 20 turned negative, coupled with the disappearance of clinical symptoms; another 12 cases responded with weak positivity accompanied by an improvement of clinical manifestations; and the remaining 5 antimony-resistant patients showed strong positive reactions, with their conditions gradually worsening. Furthermore, all 6 cases in which the diagnosis was missed by the bone marrow smear method turned McAb-AST negative after chemotherapy. These results suggest that McAb-AST can be used to evaluate the efficacy of chemotherapy as well as to avoid missed diagnosis by the bone marrow smear method.

31P NMR spectroscopy of the human heart at 4 T: detection of substantially uncontaminated cardiac spectra and differentiation of subepicardium and subendocardium

31P NMR spectroscopy of the human heart was undertaken at 4 T to investigate whether spectra localized exclusively to the myocardium can be obtained. Utilizing a Fourier series window approach to spectroscopic imaging, we find that at least two layers across the anterior left ventricle wall can be detected, with voxel sizes of about 8 cm3.

The physical, psychological, and socioeconomic costs of pediatric trauma

This prospective study examined the physical, psychological, and socioeconomic effects of injuries on children and their immediate families. Ninety-two injured children admitted with minor (ISS less than 16) or major (ISS greater than or equal to 16) injuries were compared with a control group of 59 children admitted during the same period with acute appendicitis. The two populations were similar in mean age, sex ratio, parental age and work status, and number of siblings. The parents of the injured children had a lower level of education than those of the controls. Fifty-four percent of the minor injury patients and 71% of the major injury patients had persistent physical limitations at 12 months in contrast to none of the controls. Thirty-eight percent of minor injury patients had pre-existing behavioral disturbances compared with 14% of major injury patients and 10% of controls. Behavioral disturbances among major trauma patients showed a sharp rise to 41% at 12 months and tended to persist in cases with continuing physical limitations. The major injury patients and those with significant head injuries exhibited a decrease in academic performance; minor injury patients and those without head injury showed no change. Maternal malaise rose sharply to about 40% in both injury groups in contrast to 7% in the controls and was more common in the presence of persistent physical limitations. Only 73% of families in the major injury group had returned to normal family life compared with 87% of the minor injury group and 100% of controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Identification of Leishmania donovani isolates from different kala-azar foci in China by kDNA hybridization

kDNA sequence homology of Leishmania donovani isolates from three types of kala-azar foci in China were analyzed by using dot and Southern hybridization with biotin- and 32P-labelled probes. The results revealed kDNA sequence heterogeneity among Leishmania donovani isolates from the three kala-azar foci: sequence homology between isolates of hill and desert foci was higher than that between hill and plain foci isolates. The kDNA hybridization technique was also found to be specific and sensitive for direct identification of Leishmania in animal tissues. In a preliminary survey, kDNA hybridization of cutaneous tissue blots of 71 dogs from endemic regions showed a positive rate of 40.8%, and the rate of double positive cases (touch blot hybridization and bone marrow smear) reached 91.3%. The direct identification of Leishmania in tissues by kDNA hybridization seems to be a useful and convenient method for epidemiological study and clinical diagnosis, especially for species/strain characterization.

[Identification of morphology and inorganic elements of Eucommia ulmoides Oliv. produced in Sichuan by applying scanning electron microscope with energy dispersive X-ray analysis]

A research on the identification of morphology and inorganic elements of Eucommia ulmoides produced in Sichuan has been made by applying scanning electron microscope; energy dispersive X-ray analysis. Qualitative and semi-quantitative analyses of the inorganic elements in the observed areas have been obtained.

The quantitative alteration of 5s rRNA during the development of mammalian erythroid cells and its effect on DNA synthesis in SP2/0 mouse myeloma cells

Mouse myeloma cells (SP2/0) were incubated with 125I-5s rRNA from rabbit reticulocytes and processed for autoradiography. The results indicated that 5s rRNA could pass into the nuclei of mouse myeloma cells. In a separate experiment, SP2/0 were incubated with cold 5s rRNA, then with 3H-TdR and processed for autoradiography. It was found that in the mouse myeloma cells, DNA synthesis and cell division were obviously suppressed. In another series of experiments, rRNA was extracted from rabbit bone marrow, reticulocytes and erythroid cells and from rat embryonic liver and erythroid cells. The rRNA was analyzed by agarose electrophoresis. It was found that the amount of 5s rRNA in various stages of erythroid development changed along with the denucleating process. Thus it seems likely that 5s rRNA from mammalian erythroid cells could play a role in reversing the malignant phenotype of tumor cells and denucleation of mammalian erythroid cells through inhibiting DNA synthesis.

Structural studies on metal-serum albumin. IV. The interaction of Zn(II), Cd(II) and Hg(II) with HSA and BSA

There have been no detailed and reliable studies on the environment and configuration of Zn(II), Cd(II) and Hg(II) in the metal centers of human serum albumin and bovine serum albumin to date. In this paper the authentic evidence for the involvement of the cystinyl sulfur atoms in the ligation to the zinc group ions has been obtained from the X-ray photoelectron spectra. The belief that each of the zinc group ions possesses several similar binding sites in human- and bovine serum albumin and is bound to the deprotonated thiol group (-RS-) of the cysteinyl residues to form tetrahedral and linear metal centers has been further confirmed by the treatment of ligand to metal charge transfer data with Jorgensen's method. According to these results, we have inferred that these binding sites may be located at the seventeen disulfide bridges, most likely at the seven pairs of adjacent disulfide bridges between positions 75 and 567, in the serum albumins.

Partial gene duplication as a cause of human disease

Tandem duplication of large regions of DNA, including duplication of whole genes, provides a substrate for genetic evolution. Tandem duplication of smaller regions involving parts of genes is now recognized as a contributor to the mutation spectrum that results in genetic disease. In this review, more than 30 unrelated partial gene duplications that have been implicated in the genesis of human genetic disease are presented and the pathogenic effects and frequency of such duplications are summarized. The mechanisms of duplication formation are analyzed with special emphasis on the molecular details of the nucleotide sequences at the duplication junctions. Evidence to date suggests that duplication may arise from either homologous (Alu-Alu) recombination or nonhomologous recombination, the latter possibly mediated by topoisomerases. For the dystrophin gene, in which most duplications have been identified, these recombination events are intrachromosomal, suggesting that unequal sister chromatid exchange is the major mechanism.

Progress in studies on the antimutagenicity and anticarcinogenicity of green tea epicatechins

An antioxidative fraction was extracted from green tea and the major compounds in the fraction identified as epicatechins. Experimental results showed that green tea epicatechin compounds (GTEC) inhibited the mutagenicity and/or chromosomal damage caused by different carcinogens in both bacterial and mammalian cells. In vitro, GTEC inhibited transformation of BALB/3T3 cells induced by BP, X-rays, or MCA/TPA. In vivo, green tea extract decreased the incidence of carcinoma in the forestomach and esophagus of mice induced by sarcosine and NaNO2. GTEC inhibited the development of gamma-glutamyl transpeptidase-positive foci in the livers of rats treated with diethyl nitrosamine (DEN) or DEN/phenobarbital. Our investigations indicate that the antimutagenic and anticarcinogenic mechanisms of GTBC are related to the following: increased glutathione-S-transferase activity; inhibition of edema, hyperplasia, and ODC activity induced by TPA; free radical scavenging; blocked tumor promoter-induced inhibition of intercellular communication; and enhanced cell-mediated immunity. GTEC might be useful in the prevention of some kinds of cancer and a variety of oxidation-related diseases.

[Alkaloids of plumula Nelumbinis]

Six alkaloids were isolated from the green seed embryo of Nelumbo nucifera growing in Ruichang, Jiangxi province. On the basis of physiochemical properties and spectroscopic methods (UV, IR, NMR, MS) they were identified as: lotusine, nuciferine, pronuciferine, liensinine, isoliensinine and neferine.

Visualization of MR angiographic data with segmentation and volume-rendering techniques

Novel image processing and computer graphics techniques were developed to create three-dimensional (3D) models of vasculature from magnetic resonance (MR) angiographic images of the head or neck. Region growing was used to produce a mask that isolated the vascular signal in the MR angiographic data. The masked images were subjected to gradient-shaded volume rendering to create 3D views of the vasculature. The computer-derived model of intracranial vasculature was then merged with a 3D model of brain parenchyma derived from a set of MR images. The combined display of vascular and gyral anatomy may be useful for neurosurgical planning.

An epidemiologic approach to the study of acute reversible health effects in the workplace

We present an epidemiologic approach for the study of the irritant effects of sodium borate exposure that can be used to study acute reversible health effects more generally. Acute irritant responses, such as symptoms of nasal irritation or cough, are subjective. They may, however, be accompanied by transient airway obstruction, which can be objectively measured by a change in peak expiratory flow (PEF) or forced expiratory volume in one second (FEV1). Because these physiologic responses are reversible and follow short-term peaks of exposure, they cannot be studied effectively using conventional epidemiologic methods of design and analysis. The proposed study design is a short-term prospective cohort study with frequently repeated measures of health effects and simultaneous measures of exposure. Because each subject passes through periods of high and low short-term exposure, the study has the form of a crossover design. This design permits each acute response to be linked to the corresponding short-term average exposure, providing the data necessary for dose-response analyses within subject. We present the results of the sodium borate study to illustrate the analysis of such data.

[Study on periodically prevalent feature for epidemic cerebrospinal meningitis in China]

A study on periodically prevalent feature for epidemic cerebrospinal meningitis (ECM) in China was carried out by means of cluster analysis of multilocus enzyme electrophoresis, as well as chromosomal DNA fingerprinting and subserotyping of outer membrane protein class 1 of Neisseria meningitidis group A. Two hundred strains tested were isolated from the patients for ECM and carriers during the 1960s to 1980s in 17 provinces and municipalities. Overall analysis on the bacterial types of the strains above mentioned and data of morbidity of this disease for recent 40 years was undertaken. The research results indicated that ECM really possessed the feature of cyclic prevalence in China, the cyclic epidemics were caused by the different predominant types of Neisseria meningitidis group A and the strains of predominant types could be periodically spread. Every epidemic was basically spread from the north to the south of China. However, the patterns of cyclic epidemic of this disease were not uniform in the country. The above study has established the preliminary base to reveal the prevalent mechanism for ECM by use of molecular biological methods in China.

Technique for reduction of truncation artifact in chemical shift images

The authors describe a technique to reduce truncation artifacts in chemical shift images taken for in vivo magnetic resonance spectroscopy by using boundary information available from anatomic images. In this approach, high spatial frequency components are extrapolated from the observed data by making use of the boundary information. This technique has been tested with simulations and phantom experiments. Results obtained show that the technique works very well. The authors present technical details and results of computer simulations and phantom studies.

[Surveillance of epidemiological features for epidemic cerebrospinal meningitis in China during 1980s]

This paper reports the results of surveillance of epidemiological features for epidemic cerebrospinal meningitis in China during 1980s. Although the incidence of this disease in China in 1984 were up about 50% comparing with in 1983, its morbidities of recent years had been continued to decrease. The patients were distributed rather far apart from one another and the feature of cyclic incidence peak for epidemic cerebrospinal meningitis in 1980s was not obvious as former. However, the possibility which this disease will present prevalence still exists. Because the morbidity would begin to rise again after it decreased to the lowest level. At present, such rising signs have been appeared in some provinces. In addition, Neisseria meningitidis group B isolated from the cases tended to increase. The proportion of cases of young children was increased obviously in comparison with elder children or adults. This status makes the prevention of this disease by using meningococcal polysaccharide vaccine group A some difficulty. The authors also investigated and analysed the effect of normal throat flora of healthy people and other acute respiratory infectious diseases on the epidemic cerebrospinal meningitis.

[Electron spin resonance (ESR) study on hair of rats with diabetic cataract]

The hair taken from 40 rats with diabetic cataract and 20 normal controls was tested by using ESR. It was found that the 'g factor' of the hair of the rats with diabetic cataract is higher than that in normal controls. The intensity of ESR signals of the hair taken from rats with diabetic cataract is three times higher than that of ESR signals of the hair from the normal controls. The results have suggested a good reappearance and a remarkable increase in number of the free radicals and other particles of paramagnetic substances during the course of the development of the rats' diabetic cataract. The study provides new scientific data for the theory of free radicals damaging to the crystal in the process of the formation of diabetic cataract.

[Study on the variation of relaxation time in diabetic cataractous lenses of rats by using NMRA]

Nuclear magnetic resonance analysis (NMRA) was used to measure the relaxation time T1 and T2 of the protons in the different-stage-diseased lenses of rats with diabetic cataract caused by the streptozotocin, and the results were put in comparison with those obtained from the control group, showing that after one month of medication the values of T1 and T2 in the cataractous lenses are greater than those gained from the control group. The variation, as time goes on, becomes greater and greater. T1 and T2 indicate the speed of the free induction decay (FID) signals, and the variation of the FID signals are in direct proportion to that of the proton content of the samples. This shows that an increase in T1 and T2 indicates an increase in the water content in the diseased lenses, and the changes in ratio of "bound" water to free water. Such changes may be explained that the space for "bound" water is occupied by some other macromolecules, causing the alteration of the macromolecular structure, and consequently the aggregation of protein and the degeneration or dehydration or dehydration of the membrane occur, which may give rise to another scattering centre. So the scattering of the lens increases and its transparency decreases. This result is in agreement with some reports in the medical literature. As T1 and T2 are quite different in the normal and pathological tissues, and the protons are the most extensive nucleus in all biological tissues, NMR is a very important method to determine the proton relaxation time in the biological tissue and to judge if it is normal or not.(ABSTRACT TRUNCATED AT 250 WORDS)

Alterations in the electrical properties of T and B lymphocyte membranes induced by mitogenic stimulation. Activation monitored by electro-rotation of single cells

Stimulation of either B or T lymphocytes using specific mitogens results in changes in the passive electrical properties of the cell surface. These effects can be related to growth and secretion. This was possible because the high resolution of the contra-field electro-rotation method, combined with the use of very low conductivity media, allowed accurate and analytically-derived values for the cell surface properties. Increases in effective CM (membrane capacity) and changes in apparent membrane conductivity (reflecting the additive effects of true membrane conductivity GM and surface conductance KS) were measured. After 72 h treatment with concanavalin A, thymocyte CM had increased from 0.76 muF/cm2 to 1.24-1.46 muF/cm2 (7.6 to 12.4-14.6 mF/m2). Allowing for the stimulation-induced size increase (cell radius increased from 2.8 to 4.4 micron) these data imply that the plasma membrane area per cell increases 5-fold during stimulation. Stimulation of B cells (by 3 days incubation with bacterial lipopolysaccharide) increased CM from 0.93 to 1.6-1.7 muF/cm2 (9.3 to 16-17 mF/m2). Incubation without mitogen gave no significant increase in CM or in radius. Control cells of different sizes showed no difference in membrane properties. The increases in effective CM are argued to reflect an increase in membrane ramification (microvilli, folding, etc.). The apparent membrane conductivity of T cells also increased during stimulation, from 5 to 21 mS/cm2 (50 to 210 S/m2). This increase is proportionately much greater than that in CM or in membrane area. It seems to be due to a real increase in GM, but a small increase in KS may also occur. The earliest changes in apparent membrane conductivity were evident between 3 and 5 h after stimulation, before the cells increased in size. This response parallels increases in transmembrane transport reported to follow mitogenic stimulation.

SLIM: spectral localization by imaging

Nonspectroscopic magnetic resonance (MR) imaging often shows that a slice is composed of several compartments, each of which can be assumed to have a spatially homogeneous magnetic resonance spectrum, e.g., a limb composed of fat, muscle, bone marrow, and tumor. We show how to use structural information from such a nonspectroscopic image in order to increase the efficiency of subsequent localized spectroscopic measurements. Specifically, knowledge of the boundaries of N compartments makes it possible to reconstruct compartmental spectra from spectroscopic signals from an entire cross section with N or more different degrees of phase encoding. Experimental studies of a two-compartment phantom show that this method (SLIM) can be used to derive regional hydrogen spectra of a single slice from signals with as few as 2 phase-encoding steps, although Fourier transform chemical-shift imaging requires 64 steps to achieve a result of comparable accuracy. SLIM required only 16 phase-encoding steps to obtain accurate regional single slice spectra in a human limb with three compartments. Spectra of similar quality, obtained by Fourier transform chemical-shift imaging, required 256 to 1024 steps.

The problem of Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is a lethal X-linked muscular disorder. The biochemical defect remains unknown, but the gene responsible has been mapped to band Xp21. The gene has now been cloned in two laboratories solely from knowledge of its map location. L. M. Kunkel and his colleagues isolated genomic sequences (PERT 87) from within a large deletion causing DMD, whereas our group isolated genomic sequences (XJ) spanning the junction of an X-autosome translocation causing the disease. Chromosome walking by both groups has led to the isolation of over 400 kilobases of the PERT 87 and XJ region. Subclones of PERT 87 and XJ reveal restriction fragment length polymorphisms that segregate with the DMD gene in 95% of meioses, and fail to hybridize with DNA from about 8% of male patients. Selected subclones of PERT 87 and XJ contain exons that hybridize to muscle-derived complementary DNA (cDNA) clones. The cDNA clones detect a large (16 kilobase) message. Analysis of deletions, mutations and translocations suggests a DMD gene of between two million and three million base pairs. The clones obtained so far are useful for attempts to generate antibody against the gene product and for carrier identification and prenatal diagnosis.

The effects of high iodine on the brain development of mice

C57 mice were divided into two groups: (A): experiment group (H group). Each female mouse was injected with 20 microliter iodized oil; (B): control group (N group). Both groups were mated 8 days after iodized oil injection. Urine iodine contents/24 h of H group was 20 times higher than that in N group 7 days after injection and 18 times higher two months later. Serum T4 values were determined. Brain protein, DNA, body weight, motility and learning ability were measured in the progeny. The results indicate that there was no statistically significant difference between the groups in any of the parameters mentioned above. This strongly suggests that a high iodine dose, given as iodized oil, does not have obvious damaging effects on brain development, at least in mice.

Comparison of tissue preparation methods for assay of nicotinamide coenzymes

To prepare tissues for analysis of NAD(+), NADH, NADP(+), and NADPH, common practice is to freeze samples in liquid nitrogen, often followed by freeze-drying, before extraction in HCl or NaOH. With cucumber (Cucumis sativus L.) cotyledons, prefreezing in liquid nitrogen or slower freezing to -20 degrees C yielded substantially lower values for NADH and NADPH than obtained from samples homogenized immediately in acid or base. Freeze-drying after freezing in liquid nitrogen generally caused even lower values of those coenzymes. We suggest that direct extraction is more likely to yield accurate results with cotyledons and other plant parts.

A cDNA clone from the Duchenne/Becker muscular dystrophy gene

Duchenne muscular dystrophy (DMD) is the most common of the muscular dystrophies affecting one in 3,000 live male births. Both DMD and the mild form, Becker muscular dystrophy (BMD), are X-linked. There are a number of females affected by the disease who all possess an X-autosome translocation, with the exchange point in the X always occurring within chromosome band Xp21. This, together with linkage and deletion data, has localized the gene at band Xp21. DNA fragments from this region have been cloned using a patient with a large Xp21 deletion and from a patient with a t(X:21) translocation. The former clones (pERT 87) comprise the DXS164 locus and the latter clones (XJ) the DXS206 locus. Subclones from both regions allow the detection of deletions in approximately 11% of DMD patients. A fetal muscle complementary DNA clone corresponding to exons in the DXS164 locus has been isolated and detects a 16-kilobase (kb) transcript. We present the isolation of an adult muscle cDNA clone from the DXS206 locus that detects a 16-kb mRNA in adult human muscle. The cDNA clone contains exons that map in the DXS206 locus, the DXS164 locus, and on the centromeric side of these cloned regions. The t(X;21) translocation exchange points occurs within a large intron of 105 kb or larger, indicating that the translocation has disrupted the DMD/BMD gene to cause the disease in this patient.

Correlation of dietary aflatoxin B1 levels with excretion of aflatoxin M1 in human urine

Corn and peanut oil (total, 253 samples) were collected from 32 households in Fushui county of the Guangxi autonomous region of the People's Republic of China, where high liver cancer incidence has been reported, every day over a period of 1 week and analyzed for aflatoxin B1 (AFB). A total of 252 urine samples were collected simultaneously from the residents in the households which were shown to have consumed AFB and were analyzed for aflatoxin M1 (AFM) by a competitive direct enzyme-linked immunosorbent assay. A good correlation between total dietary AFB intake and total AFM excretion in human urine was observed during a 3-day study. A regression equation of 0.143 plus 0.0135 multiplied by the amount of AFB consumed was observed. Between 1.23 and 2.18% of dietary AFB was found to be present as AFM in human urine. A good correlation was also observed between the AFB concentration in corn and the AFM concentration in human urine. The results suggest that analysis of AFM in urine by enzyme-linked immunosorbent assay could be used as an index for human exposure of AFB in an extensive epidemiological study.