Micromanipulation of chromosomes in PTK2 cells using laser microsurgery (optical scalpel) in combination with laser-induced optical force (optical tweezers)

An optical scalpel and optical tweezer have been combined to perform intracellular microsurgery and micromanipulation in vivo. When only laser microsurgery was performed on metaphase chromosomes, the dissected sister chromatid fragments drifted off to either the side of the spindle or completely off the spindle. At anaphase the fragments separated and the two arms generally moved to their respective daughter cells. When the chromosome arm was cut during anaphase A and B, the distal chromosome fragment separated from the rest of the chromosome and moved toward the pole, following the proximal chromosome fragment. Distal chromosome fragments laser-dissected during metaphase were held together throughout anaphase using the optical trap. Optical trapping of dissected chromosome fragments during anaphase A and B inhibited movement of the chromosome fragment to its pole. As a result, the trapped chromosome fragments were (1) incorporated into the opposite daughter cell, (2) lost in the cleavage furrow during cytokinesis, or (3) eventually incorporated into the correct daughter cell. These results indicate that optical traps are effective in holding laser-dissected chromosome fragments throughout mitosis. This new tool should be useful for studies on chromosome movement and cell genetics.

Analysis of chromosome 21 yeast artificial chromosome (YAC) clones

Chromosome 21 contains genes relevant to several important diseases. Yeast artificial chromosome (YAC) clones, because they span > 100 kbp, will provide attractive material for initiating searches for such genes. Twenty-two YAC clones, each of which maps to a region of potential relevance either to aspects of the Down syndrome phenotype or to one of the other chromosome 21-associated genetic diseases, have been analyzed in detail. Clones total approximately 6,000 kb and derive from all parts of the long arm. Rare restriction-site maps have been constructed for each clone and have been used to determine regional variations in clonability, methylation frequency, CpG island density, and CpG island frequency versus gene density. This information will be useful for the isolation and mapping of new genes to chromosome 21 and for walking in YAC libraries.

Pulmonary SP-A enhances adsorption and appears to induce surface sorting of lipid extract surfactant

The effect of surfactant concentration and supplementation with surfactant-associated protein A (SP-A) on the surface activity of lipid extract surfactant (LES) was examined using a captive bubble technique. Adsorption of LES is strongly concentration dependent over the range of 50-1,000 micrograms/ml. Addition of SP-A to LES at low concentrations in the presence of calcium dramatically increases the rate of adsorption. In quasistatic cycling experiments, samples containing SP-A require less compression to achieve low surface tensions even during the first compression cycle. Calculated film compressibilities at 15 mN/m indicate that SP-A alters the surfactant monolayer behavior such that in a small number of cycles the compressibility is indistinguishable from that of pure DPPC. Furthermore, SP-A reduces the incidence of bubble "clicking," suggesting a stabilization of the monolayer at low surface tensions. In dynamic cycling experiments, SP-A reduces compression of the film area required to achieve a low surface tension of approximately 1 mN/m. SP-A eliminated the plateau just below 25 mN/m normally observed during the compression phase with low concentrations of LES and the shoulder observed at approximately 35 mN/m during expansion. In the presence of SP-A and, to a lesser extent with high concentrations of LES, there is a marked lag in the increase in surface tension during the initial part of the dynamic expansion loop, with surface tensions remaining near 1 mN/m for approximately 10% of the increase in bubble area. The results indicate that SP-A enhances phospholipid adsorption during dynamic cycling and may enhance elimination of non-DPPC lipids during cycling.(ABSTRACT TRUNCATED AT 250 WORDS)

[Factors affecting prognosis of cryptococcal meningitis]

By analyzing 26 cases of clinic data in cryptococcal meningitis. The author found that the poor prognosis in cryptococcal meningitis depends on following factors: 1. younger age of patients, 2. abrupt onset, 3. course prolonged over 6 weeks, 4. complicated extracerebral cryptococcal infections and many underlying disease, 5. used corticosteroids and antibiotics longtime, 6. higher CSF pressure and lower CSF cells count most of which is neutrophilic leukocyte.

A morphological and immunohistochemical study of plasma cell proliferative lesions

Monoclonal plasma cell proliferative diseases such as multiple myeloma and plasmacytoma can involve extramedullary sites at the time of first presentation, or subsequently in the course of the disease. Under such circumstances, they can mimic primary or metastatic carcinomas, neuroendocrine or neuroectodermal tumours and lymphomas, and the pathologist often has to resort to immunohistochemistry as an aid to diagnosis. We studied the morphology and immunohistochemical properties of 10 cases of previously confirmed monoclonal plasma cell proliferative lesions retrieved from the files of the Department of Pathology, University of Malaya. Serial 4u thick paraffin sections were stained with H&E, the Unna-Pappenheim technique for nucleic acid and a panel of antibodies using a standard immunoperoxidase technique. Light chain restriction was demonstrable in most of the cases. Seven (70%) showed kappa and 2 (20%) lambda light chain restriction. The remaining case was not stainable with most of the antibodies in the panel. The majority (80%) of cases showed accompanying IgG heavy chain in the cytoplasm, while 1 case had IgA. Seven (70%) showed membrane positivity with antibody to epithelial membrane antigen (EMA) and 7 (70%) cytoplasmic positivity with antibody to vimentin. This study enhances our awareness that neoplastic plasma cells can be positive for EMA and vimentin, and cautions us from misinterpreting these lesions as carcinomas or sarcomas. Notwithstanding that, immunohistochemical staining for kappa and lambda light chains can be helpful in differentiating monoclonal plasma cell proliferations from polyclonal ones.

Recombinant retroviruses encoding human papillomavirus type 18 E6 and E7 genes stimulate proliferation and delay differentiation of human keratinocytes early after infection

Human papillomavirus (HPV) DNAs are detected in most genital dysplasias and cancers, suggesting that these viruses perturb epithelial growth and differentiation. The E6 and E7 genes of HPV type 18 induce immortality in keratinocytes cultured from genital tract epithelia, and the immortal cell lines display aberrant squamous differentiation. To examine whether the E6 and E7 proteins directly alter keratinocyte growth and differentiation, high-titer recombinant retroviruses were constructed for efficient transfer and expression of HPV-18 genes E6, E6* and E7 in cultures of normal human keratinocytes. Infection with retroviruses encoding E6 and E7 stimulated cell proliferation, reduced the requirement for bovine pituitary extract and induced immortality. E6 and E7 also delayed but did not prevent the onset of terminal squamous differentiation. The magnitude of effects on growth and differentiation of cultured cells was directly related to levels of E7 protein expression. Thus, expression of the HPV-18 E6 and E7 genes stimulates cell proliferation and delays differentiation of keratinocytes in vitro.

HLA-DQ beta chain can present mouse endogenous provirus MTV-9 product and clonally delete Tcr V beta 5+ and V beta 11+ T cells in transgenic mice

The elusive Mls gene(s) are mouse mammary tumor virus genes. The endogenous cotolerogen involved in the clonal deletion of Tcr V beta 5.1, 5.2, and 11 in H-2E+ mouse strains has been narrowed down to MTV-9. We demonstrate that similar to H-2E alpha molecules, human DQw6 beta chain mediated clonal deletion of Tcr V beta 5.1, 5.2, and 11 also requires the MTV-9 gene product. This shows that human class II molecules can present mouse retroviral antigen. Further, backcross analysis involving [B10.M(DQb) x DBA/1] suggest a second cotolerogen in the B10.M background in the clonal deletion of V beta 5-bearing T cells.

The ?-subunit of the skeletal muscle sodium channel is encoded proximal to Tk-1 on mouse Chromosome 11

Recent evidence suggests that the human neuromuscular disorders, hyperkalemic periodic paralysis and paramyotonia congenita, are both caused by genetic defects in the alpha-subunit of the adult skeletal muscle sodium channel, which maps near the growth hormone cluster (GH) on Chromosome (Chr) 17q. In view of the extensive homology between this human chromosome and mouse Chr 11, we typed an interspecies backcross to determine whether the murine homolog (Scn4a) of this sodium channel gene mapped within the conserved chromosomal segment. The cytosolic thymidine kinase gene, Tk-1, was also positioned on the genetic map of Chr 11. Both Scn4a and Tk-1 showed clear linkage to mouse Chr 11 loci previously typed in this backcross, yielding the map order: TrJ-(Re, Hox-2, Krt-1)-Scn4a-Tk-1. No mouse mutant that could be considered a model of either hyperkalemic periodic paralysis or paramyotonia congenita has been mapped to the appropriate region of mouse Chr 11. These data incorporate an additional locus into the already considerable degree of homology observed for these human and mouse chromosomes. These data are also consistent with the view that the conserved segment region may extend to the telomere on mouse Chr 11 and on human 17q.

Demonstration of synergistic effects of hyperthermia and photodynamic therapy using the chick chorioallantoic membrane model

The chick chorioallantoic membrane (CAM) model was used to study vascular effects of photodynamic therapy (PDT) and hyperthermia (HPT) and the synergism of these modalities. The CAM is a convenient medium for monitoring the modifications of the vasculature. It is possible to view the CAM and to examine structural changes of individual blood vessels in real time. Moreover, the CAM is a closed system which lends itself to mathematical modeling of the temporal and spatial temperature profile and in which HPT can be performed quantitatively and to a selected depth, using different lasers. A porphyrin-type photosensitizer solution was applied to areas of the CAM, defined by teflon O-rings placed on the surface. Uptake dynamics of the sensitizer into the CAM was determined by analyzing its fluorescence in vivo. The CAM area was irradiated with a dual-wavelength laser system composed of a dye laser at 644 nm (to induce PDT) and a CO2 laser at 10.6 microns (to bring about HPT). Damage to the CAM vasculature, due to combined PDT+HPT, was compared to the outcome of the separate modalities, and a synergistic effect of about 40% was observed.

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.

Estimates of quantitative genetic parameters of immunological traits in the chicken

Three in vivo assays were used to measure the immunocompetence of chickens in two generations of a selection experiment. The obtained data were used to estimate the variance components for sire and dam for antibody production to Pasteurella multocida and Mycoplasma gallisepticum vaccines, for T-cell-mediated immunity evaluated by a phytohemagglutinin wing web assay, and for clearance of foreign particles from the circulatory system. Heritabilities of and genetic correlations among these immunological traits were calculated from the sire variance components. Heritability estimates of the immunological traits based on the sire component of variance ranged from .06 to .53, and genetic correlations among immunological traits were generally negative.

[Analysis of leptospiral deoxyribonucleic acids by restriction endonucleases]

For the application of restriction endonuclease analysis in typing and identifying leptospira, we selected some serovars and isolates, and analysed preliminarily their DNA with four restriction enzymes, EcoR I, Bgl II, Hha I, and Hind III. The DNA samples were isolated from the reference strains and isolates as follows: Serovar lai 56601, 017 (the virulent strain for PDH model of guinea pig), Serovar autumnalis 56606, Serovar manhao II 67020, and isolates 87112 and 87369. Each 2 micrograms of DNA was digested with 20mu of restriction enzyme at 37 degrees C for 2h and electrophoresed in 0.8% agarose gel. The gels were stained in ethidium bromide and photographed with UV light. In our experiments, apparently different restriction patterns of serovar lai 017 were observed with four restriction enzymes. Serovar lai, serovar autumnalis and serovar manhao II showed different patterns with EcoR I, especially in high molecular regions. We also observed in serovar lai 017 a distinct 10.5kb band which was obscure in 56601, the reference strain of serovar lai, after EcoR I digestion. The three serovars showed some delicate differences in Hind III restriction pattern. The two isolates from Apodemus agrarius in Sichuan (1987) 87112 and 87369 had patterns identical to those of serovar lai 56601, 017 with EcoR I, and 87112 also had a pattern identical to 56601, 017 with Hind III. Our results indicate that selected three serovars can be identified by analysis of their DNA with EcoR I and Hind III. It is suggested that restriction endonuclease analysis be a good method in typing and identify leptospira and in studying the differences of special DNA molecules.

Verapamil improves rat hepatic preservation with UW solution

Verapamil, a calcium channel blocker, improves myocardial preservation during cold cardioplegia and protects against renal damage during periods of warm and cold ischemia. To determine if verapamil could prevent ischemic damage to livers during and after cold storage, harvested rat livers were flushed with either University of Wisconsin (UW) solution or UW solution with 25 mg/liter verapamil. Twenty rats were used in each group. After 24 hr of storage at 4 degrees C, livers were perfused with oxygenated blood through the portal veins for 2 hr at 37 degrees C and pH 7.4. Liver enzymes, electrolytes, and perfusate flow rate were determined at 30-min intervals. At 90 min of perfusion, the verapamil group of livers had less elevation of AST (110 +/- 17 IU/liter vs 172 +/- 25 IU/liter, P less than 0.05), ALT (115 +/- 21 IU/liter vs 210 +/- 34 IU/liter, P less than 0.05), and LDH (962 +/- 170 IU/liter vs 1452 +/- 253 IU/liter, NS). Verapamil livers produced more bile than controls (6.9 +/- 1.9 microliters/g vs 2.3 +/- 1.7 microliter/g, P less than 0.05) and maintained a higher portal flow rate throughout the perfusion. Both groups showed similar reduction in liver weights after storage (3.9 +/- 0.9% vs 2.8 +/- 0.7%) and required the same amount of bicarbonate for correction of acidosis during perfusion (2.6 +/- 0.2 mM vs 2.8 +/- 0.2 mM). Light microscopic exam after perfusion showed hepatocyte damage in 30% of control livers, but 0% of verapamil livers. We conclude that verapamil-treated rat livers showed less damage and better function upon reperfusion after 24 hr of cold storage. This agent may be clinically useful as an additive to the UW preservation solution for livers.

Effects of hydrogen sulfide exposure on surface properties of lung surfactant

Hydrogen sulfide is an irritant and chemical asphyxiant gas that exerts its primary toxic effects on the respiratory and neurological systems. Exposure to hydrogen sulfide above a threshold value of 200-300 ppm is characterized by the sudden onset of hemorrhagic pulmonary edema. The purpose of this study was to determine whether this response is associated with changes in the surface properties of pulmonary surfactant. Bronchoalveolar lavage fluid was retrieved from the lungs of Fischer 344 rats exposed to two concentrations of hydrogen sulfide or fresh air for 4 h. Surface tension-lowering properties were assayed using a captive bubble surface tensiometer. Lung injury was assessed by histopathology and measurements of total protein and lactate dehydrogenase activity in the lavagate. Marked abnormalities in surfactant activity were demonstrated in the lavagates from rats exposed to the highest concentration (300 ppm) of hydrogen sulfide. These involved the properties of adsorption to the air-water interface and surface tension lowering under quasi-static interfacial compression. Exposure to 200 ppm hydrogen sulfide had no effect on minimum surface tension despite a significant increase in protein and lactate dehydrogenase in the lavagate. This would suggest a threshold-type response for the inhibition of surfactant activity by hydrogen sulfide. In vitro studies using normal rat surfactant showed that the abnormalities in surfactant activity were due to inhibitors in the edema fluid and not to a direct effect of sulfide on surfactant. The pathophysiological consequences of increased alveolar surface tension after hydrogen sulfide exposure may need to be considered in the clinical setting.

Selecting for efficiency of egg production using food-consumption records in layer-type chickens

1. The purpose of the experiment was to evaluate the use of food consumption records in selection to improve layer-type chickens. 2. Twelve subpopulations of Leghorns, including 5878 tested birds, were used in a selection experiment which lasted 5 generations. Four were selected using an index (I1) that combined information on body weight (BW), egg-mass output (EM), and individual food-consumption records (FC). Four were selected using an index (I2) that combined information just on BW and EM. The remaining 4 served as controls, with selection differentials set to zero in each generation. 3. Differences between the selected groups, control-corrected each generation, measured the "food-record effect". 4. Including food-consumption records in the selection criterion resulted in increased body weight (7%), reduction in food consumption (6 to 9%), increase in food efficiency (egg mass/food consumption) (2 to 5%), and increase in income over food costs (10%), relative to selection not involving food records.

RecA-dependent incision of psoralen-crosslinked DNA by (A)BC excinuclease

Previous work to elucidate the mechanism of crosslink repair by (A)BC excinuclease has shown that a psoralen-crosslinked duplex is selectively incised in the furan-side strand, while a three-stranded structure is incised in the pyrone-side strand of the crosslink. These observations support a sequential incision and recombination model for the complete error-free repair of a psoralen crosslink. The work presented here extends these findings by demonstrating that in the presence of RecA protein and a homologous DNA oligonucleotide, (A)BC excinuclease is induced to incise the pyrone-side strand of a crosslinked double-stranded plasmid molecule. This finding adds further support to the current model for error-free crosslink repair.

Bone mineral density and physical activity in 50-60-year-old women

The bone mineral density (BMD) of the calcaneus was measured utilizing a single energy photon absorption method in 108 women, aged 50-60 years. The women who participated in vigorous exercise two or more times a week or whose total physical activity amounted to 4 h a week had significantly higher BMD values than those who exercised less than two times a week or did less than 4 h physical activity a week. The physically active women also showed higher values for leg extension force and maximal oxygen uptake. BMD and leg extension force were positively correlated, whereas correlations between BMD and body mass, and the width of the calcaneus were negative. When other life-style variables were taken into account, such as smoking and drinking, a significant difference in BMD was found between physically active and sedentary women, but not between the smokers and non-smokers, or the drinkers and non-drinkers.

Laser induced cell fusion in combination with optical tweezers: the laser cell fusion trap

A single-beam gradient force optical trap was combined with a pulsed UV laser microbeam in order to perform laser induced cell fusion. This combination offers the possibility to selectively fuse two single cells without critical chemical or electrical treatment. The optical trap was created by directing a Nd:YAG laser, at a wavelength of 1.06 microns, into a microscope and focusing the laser beam with a high numerical aperture objective. The UV laser microbeam, produced by a nitrogen-pumped dye laser (366 nm), was collinear with the trapping beam. Once inside the trap, two cells could be fused with several pulses of the UV laser microbeam, attenuated to an energy of approximately 1 microJ/pulse in the object plane. This method of laser induced cell fusion should provide increased selectivity and efficiency in generating viable hybrid cells.

Mapping of cosmid clones in Huntington's disease region of chromosome 4

Huntington's disease (HD) is tightly linked to genetic markers in 4p16.3. We have used a regional somatic cell hybrid mapping panel to isolate and map 25 cosmids to the proximal portion of 4p16.3 and 17 cosmids to the distal portion. The latter were positioned by long-range restriction mapping relative to previously mapped markers. One cosmid, L6 (D4S166), spans the critical breakpoint in the mapping panel that distinguishes proximal and distal 4p16.3. Four of the cosmids mapped distal to D4S90, the previous terminal marker on 4p, and stretched to within 75 kb of the telomere. Several of the cosmids that mapped between L6 and D4S90 were clustered near a number of previously isolated clones in a region with many NotI sites. Cosmid E4 (D4S168) was localized immediately proximal to the one remaining gap in the long-range restriction map of distal 4p16.3. Although pulsed field gel mapping with E4 failed to link the two segments of the map, the intervening gap was excluded as a potential site for the HD gene by genetic analysis.

Mechanical efficiency of locomotion in females during different kinds of muscle action

The mechanical efficiencies (ME) of pure positive and pure negative work as well as of stretch-shortening cycle (SSC) exercise were investigated with a special sledge apparatus. The subjects were 20 young females who performed six different types of submaximal exercise: two of pure concentric exercise (positive work), two of pure eccentric exercise (negative work) and two SSC exercises. The work intensities were determined individually, from the recordings of distance obtained during a single maximal concentric exercise. Each exercise involved 60 muscle actions lasting a total of 3 min per testing condition. The MEs of pure positive work with intensities of 30% and 60% maximum (C30 and C60 respectively) were 15.5%, SD 2.6% and 14.3%, SD 1.9%, respectively. In pure negative work, when the dropping heights were 20 cm (E20) and 80 cm (E80), MEs were 28.4%, SD 6.9% and 47.9%, SD 10.1%, respectively. In SSC-exercise, the MEs during the positive phase of the take-off were 31.3%, SD 6.3% (E20/C90) and 35.0%, SD 7.0% (E80/C69). The total MEs in SSC-exercise were 29.1%, SD 4.0% (E20/C90) and 40.1%, SD 5.2% (E80/C60 x 100). In pure negative work, the increased stretching velocity increased the value of ME. In the concentric phase of SSC-exercise, the integrated electromyographic activity (iEMG) of vastus lateralis (VL) and vastus medialis (VM) muscles were lower (P less than 0.05) than in pure concentric work, when the mechanical work was the same (C60 vs E80/C60). During pure eccentric work, iEMGs were lower in comparison to the eccentric phase of SSC-exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Genetic structure and DNA sequences at junctions involved in the rearrangements of Bacillus subtilis strains carrying the trpE26 mutation

Studies on the region upstream to ribosomal operon rrnD of Bacillus subtilis led to the characterization of two of the four chromosomal junctions involved in the rearrangements (a translocation and an inversion) of the strains carrying the trpE26 mutation. Genetic analysis, by integrative mapping, showed linkage of rrnD to cysB and hisA (both on segment A) in the trpE26-type strains. Physical analysis showed that the region upstream to rrnD is now linked to the trpE-ilvA chromosome segment as demonstrated by analyzing restriction site-polymorphism between 168 and trpE26-type strains. Similar experiments confirmed the previous genetic data on linkage in these areas in strains carrying novel rearrangements derived from the trpE26-type strains: stable merodiploids and inversions. The nucleotide sequence of the area 5' to rrnD in both types of strains (168 and trpE26), the region downstream of the citG gene and the region carrying the trpE26 mutation (made available to us by D. Henner) provided evidence for the molecular basis of the differences in structure, allowed the identification of the break points and revealed the presence of a polypurine region upstream to rrnD as seen in other systems in B. subtilis. No extensive homology was found between pairs of junctions so far sequenced. The models proposed by C. Anagnostopoulos for the role of DNA sequences of intrachromosomal homology involved in the transfer of the trpE26 mutation and the formation of novel arrangements require therefore reevaluation.

[The changes of beta-glucuronidase in rabbit model with calcium bilirubinate stone]

The aim of the present study is to determine the beta-glucuronidase changes in bile and hepatobiliary tissue of rabbit model having pigment gallstone by means of biochemical and enzymehistochemical assay methods. The result showed both of the bacterial and non-bacterial beta-glucuronidase take part in the course of pigment gallstone formation. The bacterial beta-glucuronidase level increased quickly before the formation of gallstone, then decreased with control of bacterial infection. Non-bacterial beta-glucuronidase increased slowly in pro-formation stage of gallstone, then kept high level for long period of time. The relationship between beta-glucuronidase and pigment gallstone formation is also discussed.

Neuromuscular adaptations and serum hormones in females during prolonged power training

Training-induced adaptations in the neuromuscular and endocrine systems were investigated in seven females during prolonged power type strength training. Great (p less than 0.05) changes occurred primarily during the earlier weeks of the 16-week training especially in the time of force production (from 161 +/- 107 to 93 +/- 65 ms to produce a 500 N force) and, correspondingly, in the average forces in the earlier positions of the (absolute) force-time curve of the leg extensor muscles. These changes were accompanied by significant (p less than 0.05) increases in the neural activation of the trained muscles in the earliest positions of the IEMG-time curve. Hypertrophic changes, as judged from muscle fibre area data of both FT and ST types, were only slight (ns.) during the entire training period. No statistically significant changes occurred during the training in mean concentrations of serum testosterone, free testosterone, follicle stimulating hormone (FSH), luteinizing hormone (LH), cortisol, progesterone, estradiol (E2) or sex hormone-binding globulin (SHBG). However, the individual mean serum levels of both total and free testosterone correlated significantly (r = .81-.95, p less than 0.05-0.01) with the individual changes during the training in the time of force production and in the forces in the force-time curve of the trained muscles. The present results in female subjects indicate the important role of training-induced adaptations in the nervous system for muscular power development. In females testosterone may be of great importance for muscular power and/or strength development during prolonged training and an important indicator of the trainability of an individual.

Regulation of thyroid hormone binding to its cytosolic binding protein by L-alpha-alanine

The human cytosolic thyroid hormone binding protein (p58) was recently shown to be a monomer of pyruvate kinase, subtype PKM2, and have intrinsic pyruvate kinase activity. The present study evaluated the effect of L-alpha-alanine on the binding of 3,3',5-triiodo-L-thyronine (T3) and enzymatic activity of p58. Analysis of the competitive binding data indicated that alanine, at the physiological concentration, is a non-competitive inhibitor of T3 binding to p58. Furthermore, alanine was found to be a "mixed" inhibitor of the substrate phosphoenol pyruvate. However, binding of alanine to p58 did not block the association of p58 to form the tetrameric pyruvate kinase.

In vivo vibrational wave propagation in human tibiae at different ages

Vibrational wave propagation was tested in vivo on the tibial bone of both legs of 56 female volunteers. The impact was produced by a hammer with a force strain gauge and the response was monitored by two accelerometers. The peak amplitude of the accelerations, the velocity of the acceleration wave propagation and damping were analysed for comparison among the different age groups. The results showed significant negative correlations between age and the peak amplitude of acceleration, and the velocity of acceleration wave propagation (p less than 0.01). The damping time of the acceleration wave also had a negative correlation with age. These findings suggested that age differences were related to the differences in the mechanical properties of bone. With reduction of bone mineral density, the velocity of the vibrational wave propagation would decrease, with simultaneous increase in impedance. In addition, wave absorption would be accelerated. It is suggested that this method could be used as an indicator of bone density. The method could also be developed to provide an index to monitor the progress of osteoporosis.

Pediatric total colonoscopy

One hundred fifty-one total colonoscopies were performed in 105 children ranging from 1 month to 15 years of age. The cecum was reached successfully in 136 examinations without complications, generally within 30 minutes. Our major indications for total colonoscopy were abnormal findings in a contrast enema, undiagnosed rectal bleeding, and possible organic lesion causing intussusception. All procedures were performed using sedation only. The pediatric gastroscope was employed for total colonoscopy on infants less than 6 years of age; the cecum was reached successfully in 98 of 106 procedures with this instrument. Our total colonoscopy series contributed to the diagnosis of various disorders in 86 children and of normality in the 19 remaining children. The results suggest that, if performed with proper precautions and techniques, total colonoscopy is a safe and useful procedure with which to examine the entire colon of infants and children.

Changes in occupational role performance after a severe burn: a retrospective study

Ten men with severe burn injuries were interviewed to examine their perceptions of the residual impact of severe burn on performance in self-care, home management, work, and leisure occupations within the year after rehabilitation. Three patterns of occupational role performance after a burn were identified: (a) a resumption of participation in all four occupational categories; (b) a return to independence in self-care with substantive impairment in home management, work, and/or leisure roles; and (c) substantive disruption in all occupational roles. Role loss or disruption was commonly associated with reduced endurance, intolerance for standing and walking, and impaired grip strength and upper extremity skill. Suggestions for rehabilitation programming and research are made.

Rapid Growth of Magnesium-Carbonate Weathering Products in a Stony Meteorite from Antarctica

Nesquehonite, a hydrous magnesium carbonate, occurs as a weathering product on the surface of the Antarctic meteorite LEW 85320(H5 chondrite). Antarctic meteorites have resided on the earth for periods of 10(4) to 10(6) years, but the time needed for weathering products to form has been uncertain. Isotopic measurements of delta(13)C and delta(18)O indicate that the nesquehonite formed at near freezing temperatures by reaction of meteoritic minerals with terrestrial water and carbon dioxide. Results from carbon-14 dating suggest that, although the meteorite has been in Antarctica for at least 3.2 x 10(4) to 3.3 x 10(4) years, the nesquehonite formed after A.D.1950.

Use of psoralen-modified oligonucleotides to trap three-stranded RecA-DNA complexes and repair of these cross-linked complexes by ABC excinuclease

A series of site-specifically cross-linked, three-stranded complexes has been prepared using the RecA protein, form I (covalently closed and negatively supercoiled) pUC19 plasmid, and eight psoralen-monoadducted oligonucleotides between 30 and 107 residues in length. Complexes formed much less efficiently if linearized pUC19 was used as the duplex substrate. Quantitative analysis indicates that although RecA is able to utilize a 30-mer in its homologous pairing reaction, incorporation at 50% efficiency requires a single-stranded substrate at least 50 residues long. These three-stranded complexes have been used to study the action mechanism for cross-link repair by ABC excinuclease, and the results are consistent with the recent model of Van Houten, B., Gamper, H., Holbrook, S. R., Hearst, J. E., and Sancar, A. (1986b) Proc. Natl. Acad. Sci. U. S. A. 83, 8077-8081.

Genetic analysis of immunocompetence measures in a White Leghorn chicken line

Immunocompetence of the Iowa State University S1 White Leghorn chicken line was studied. This line was divided into eight sublines based upon erythrocyte antigen B (Ea-B) allele (B1B1 or B19B19), antibody response to glutamic acid60-alanine30-tyrosine10 (GAT) (high or low), and response to Rous sarcoma virus-induced tumors (progression or regression). Antibody responses to Pasteurella multocida (PM), Mycoplasma gallisepticum (MG), and infectious bursal disease virus vaccines were evaluated by enzyme-linked immunosorbent assay. Phagocytic activity and T cell-mediated response were measured by carbon clearance and phytohemagglutinin (PHA) injection assays, respectively. Significant haplotype (subline) differences and sire family differences were observed in all three measurements. Significant sex differences were observed in phagocytic activity and T cell-mediated responses. Haplotypes with high antibody responses to GAT had significantly higher antibody titers to PM and MG vaccines than haplotypes with low antibody responses. Significant positive correlations were observed between antibody levels to the two vaccines. A significant negative correlation was seen between phagocytic activity and T cell-mediated response of females. The data suggest that the total immunocompetence profile of an individual must be considered to select for optimum immune responsiveness.

Inbreeding effects on fertility and hatchability associated with the formation of sublines

The deleterious effect of inbreeding on fertility and hatchability was studied in a population of Leghorns developed primarily for immunogenetics studies. The 1983 population averaged 42% inbreeding and traced back to only two sires and five dams of the 1965 base population. Up to 1975 (Period 1), the population was maintained as a single-unit closed flock, during which time inbreeding increased an average of 1.44% per year. After 1975 (Period 2), the population was split into five sublines. Inbreeding then increased at the average rate of 2.7% per year. The regression of fertility on inbreeding was -.31 +/- .04 in Period 1 and -.17 +/- .06 in Period 2. Corresponding values for hatchability of fertile eggs were +.08 +/- .05 in Period 1 and -.24 +/- .07 in Period 2. The regression of hatchability of total eggs set was -.15 +/- .04 in Period 1 and -.35 +/- .10 in Period 2. The evidence implies that both fertility and hatchability have a heritable basis. As expected, the deleterious effects of inbreeding on reproduction was more severe in Period 2, with sublining.

Study on erythrocyte membrane fluidity by laser Raman spectroscopy

Differences between patients with cirrhosis of liver, nephrotic syndrome, coronary heart disease and normal subjects in laser Raman spectra of erythrocyte membranes have been found. In regions of 1000-1140 cm-1 and 2840-3000 cm-1, the ratios I1130/I1080 and I2890/I2850 in patient membranes are higher than those in normal ones respectively. These results mean that erythrocyte membrane fluidity of these patients is reduced. This reduction may be attributed to the possibility that erythrocyte membrane of patients get more cholesterol from their plasma and resulted in the modification of the ratio of cholesterol/phospholipids in the membranes.

Polyamine metabolism in an obligately alkalophilic Bacillus alcalophilus that grows at pH 11.0

Bacillus alcalophilus, an obligately alkalophilic bacterium that grows at pH 11.0, has an intracellular pH of 9.5 or less. Unlike all other living organisms, polyamines (putrescine, spermidine and spermine) in B. alcalophilus, if present, will be largely unprotonated. HPLC analysis indicated that spermidine is the major polyamine in B. alcalophilus, accounting for more than 90% of total polyamines, and the level of spermidine varies during growth. Ornithine decarboxylase activity was not detectable in B. alcalophilus under all conditions examined. When [3H]arginine was added to the culture medium, the radioactivity can be recovered from polyamine pool; the distribution is 3% for putrescine, 94% for spermidine, and 3% for spermine, suggesting the presence of arginine pathway for polyamine biosynthesis. The polyamine transport system in B. alcalphilus appears to be Na+-dependent and is highly sensitive to the inhibition of gramicidin S and valinomycin.

Isolation of the structural genes for the Rieske Fe-S protein, cytochrome b and cytochrome c1 all components of the ubiquinol: cytochrome c2 oxidoreductase complex of Rhodopseudomonas capsulata

The structural genes for the Rieske Fe-S protein (petA), cytochrome b (petB) and cytochrome c1 (petC) subunits of the ubiquinol:cytochrome c2 oxidoreductase (bc1 complex) of Rhodopseudomonas capsulata have been cloned by complementation, using a mutant defective in this complex. The location of these genes on the obtained plasmid, pR14A, was determined using synthetic mixed oligonucleotide probes corresponding to highly conserved amino acid sequences of these proteins from various organisms. Their correct identity was established by partial sequencing. The petA, petB and petC genes were found to lie close to each other in this order, spanning two adjacent EcoRI fragments of 2.7 X 10(3) and 1.3 X 10(3) base-pairs, respectively. An insertion-deletion mutation, covering most of petB and all of petC and an insertion mutation, located in petB were constructed in vitro and were introduced into the chromosome of an otherwise wild-type strain by gene transfer agent-mediated genetic crosses. The bc-1 mutants obtained were defective in photosynthesis but, as expected, they could grow by respiration because of a branched respiratory pathway. Therefore, in R. capsulata a functional bc1 complex is essential in vivo for photosynthesis but not for respiration. Further, in the respiratory pathway the branch point must be before the bc1 complex, most likely at the quinone pool. These mutants were also proficient in anaerobic growth in the presence of dimethylsulfoxide, indicating that a functional bc1 complex is not required for this pathway. Several other insertions and deletions, located outside of the pet gene cluster, were also constructed. The ability of these latter mutants to grow photosynthetically suggested that no other gene essential for photosynthesis is located in the proximity of the pet cluster. The plasmid pR14A was shown to complement in trans the bc-1 insertion or insertion-deletion mutants, indicating that the pet genes were expressed in R. capsulata. Cross-hybridization experiments showed that the pet cluster was quite distinct from other known genes involved in photosynthesis.

Effects of washing and gel filtration on the ultrastructure of human platelets

The ultrastructure of washed and gel-filtered platelets has been examined by scanning- and transmission-electron microscopy. Three different washing procedures previously established for functional studies have been employed. Each washing method resulted in typical morphologic alterations of the platelets. Gel filtration of platelet-rich plasma appeared less harmful than washing. Specimens fixed immediately after elution contained numerous platelets with typical shape changes which were restored almost completely after incubation at 37 degrees C. Our study emphasizes the need for cautious interpretation of results obtained with separated platelets and mandates morphologic controls for such experiments.