An essential iteron-binding protein required for plasmid R1162 replication induces localized melting within the origin at a specific site in AT-rich DNA

The R1162-encoded protein RepIB is essential for replication of the plasmid and binds specifically to iterons within the replicative origin. The protein causes the localized melting of DNA (determined by sensitivity to P1 nuclease) at a site within the AT-rich region of the origin, about 60 bp from the iteron binding sites and separated from them by a GC-rich tract. Point mutations have been isolated in the AT-rich DNA. These mutations interfere with origin activity and also prevent the protein-induced sensitivity to P1. A second-site suppressor of one of these mutations maps in the repIb gene and restores both origin function and sensitivity to P1. The results suggest a specific interaction between RepIB and origin DNA at a position distant from its primary binding site.

Efficacy of recombinant human macrophage colony-stimulating factor in combination with whole-body hyperthermia in the treatment of mice infected with the polycythemia-inducing strain of the Friend virus complex

Macrophage colony-stimulating factor (M-CSF, CSF-1) and whole-body hyperthermia (WBH) were evaluated, alone or in combination, for their capability to influence disease progression in mice inoculated with the polycythemia-inducing strain of the Friend virus complex (FVC-P). DBA/2 mice were injected i.v. with FVC-P and were treated with 20 micrograms/dose M-CSF s.c. twice a day for 5 days beginning 6 days after injection of FVC-P and/or with WBH (between 38.8 degrees C and 40.2 degrees C) given on days 5 and 12 after FVC-P injection. Fourteen days after viral inoculation, mice were sacrificed and spleen cells evaluated for: 1) spleen focus-forming virus (SFFV), by the spleen focus-forming unit assay (SFFU); 2) SFFV mRNA and genomic DNA using, respectively, Northern and Southern analysis with a B-E-SFFV DNA probe; and 3) natural killer (NK) cell activity, by 51Cr-release assay. Treatment with M-CSF or WBH alone had a small effect on SFFU numbers but little or no effect on SFFV mRNA expression and SFFV-specific DNA. However, dramatically decreased levels of SFFU and SFFV mRNA and specific DNA fragments were observed in mice treated with M-CSF in combination with WBH, and NK cell activity was restored to normal. These results suggest the possibility that M-CSF may have a therapeutic effect in combination with WBH in the in vivo treatment of certain hematologic malignancies and/or retroviral infections.

High level expression of human tissue-type plasminogen activator gene in mouse C127 cell

We have expressed human tissue plasminogen activator (t-PA) gene at high levels in a mouse cell line. The t-PA cDNA with deletion of the long 3' untranslated region was inserted into a bovine papilloma virus (BPV) derived vector under the control of a mouse metallothionein promoter. The mouse metallothionein (mMT) gene also provided signals for splicing and polyadenylation. Mouse C127 cells transfected with this construct secreted t-PA at high levels into the cell culture medium. When an SV40 polyadenylation signal was inserted between the t-PA cDNA and the mMT splicing signals, the expression level increased by several fold. The expression levels did not increase further upon either introduction of Rous sarcoma virus LTR into the plasmid or mutation of the translation initiation context sequence to conform with the consensus one. Most of the plasmid appears to be integrated into the host chromosome. Cells producing high levels of t-PA tend to detach from the dish in a few days after passage. When grown on porous microcarriers, however, such cells can be maintained in culture for months and t-PA can be harvested continuously.

Movement toward stability as a fundamental principle of population dynamics

Although convergence to stability is typically a complex and irregular process, the Kullback distance provides a measure that moves consistently to 0 as a population becomes stable. The roots of the Kullback distance are in information theory, but it is a meaningful demographic quantity. It reflects a population's log momentum, or the amount of growth built into a population's nonstable age distribution. The rate at which the Kullback distance moves toward 0 is neither constant nor monotonic. At any point in time, however, it decreases by the covariance between a population's age-specific growth rates and its log momentum. Although the present findings are couched in terms of movement toward stability, they are generally applicable because they relate to the behavior of any population at any instant. It is a fundamental principle of population dynamics that a population is always moving toward the stable population implied by its prevailing fertility and mortality rates, and that the extent of its movement is determined by the covariance between its age-specific growth and its log momentum.

Ploidy in invasive colorectal cancer. Implications for metastatic disease

A retrospective study was performed to determine the ploidy of superficial (above muscularis propria) and deep (below muscularis propria) biopsy specimens from the primary colorectal cancer of 88 patients with Dukes Stage C2 and D colorectal tumors. The ploidy of lymph node and liver metastases was compared with that of the superficial and deep specimen from the corresponding primary tumor. Among the tumors studied, 78% exhibited nondiploid stemlines. In 19% of the tumors, the ploidy of the superficial biopsy differed from that of the deep biopsy. Among these discordant tumors, all of the deep biopsy specimens corresponded in ploidy to the liver metastases, whereas most of the superficial specimens were similar in ploidy to the lymph node metastases. Our observations suggest that measurement of a single site may not be sufficient to detect nondiploid stemlines within a tumor. They also suggest that measurement of deeper parts of invasive tumors may be more reflective of the phenotype of distant metastases than measurement of superficial specimens.

Fluorescence quenching studies on the characterization of energy generated at the NADH:quinone oxidoreductase and quinol oxidase segments of marine bacteria

Generation of membrane potential (inside-positive) and delta pH (inside-acidic) at two kinds of NADH:quinone oxidoreductase segments, the Na(+)-motive segment and another segment, of Vibrio alginolyticus was examined by monitoring the quenching of fluorescence of oxonol V and that of quinacrine, respectively, with inside-out membrane vesicles. Transient generation of membrane potential at the segment occurred when ubiquinone-1 was added in the presence of KCN and NADH. The membrane potential was resistant to a proton conductor, carbonylcyanide m-chlorophenylhydrazone, indicating that the membrane potential was generated specifically at the Na(+)-motive segment. On the other hand, neither membrane potential nor delta pH was generated at another segment. The Na(+)-motive segment did not generate delta pH, indicating that only Na+ is extruded at this segment. Furthermore, generation of membrane potential and delta pH at the NADH:quinone oxidoreductase segment of V. anguillarum was examined by using the fluorescence quenching technique. This segment of the bacterium was also found to generate delta psi by the extrusion of Na+ but not H+. These results revealed that the fluorescence quenching technique is useful for the rapid identification and characterization of the respiratory segment involved in Na+ translocation.

Effect of split low dose total body irradiation on SFFV mRNA, genomic DNA and protein expression in mice infected with the Friend virus complex

DBA/2 mice infected with lethal dosages of Friend virus complex (FVC) can be 100% cured by split-dose total body irradiation (TBI) at 150 cGy, an effect associated with the restoration of the cellular immunity which is compromised by the virus. The exact mechanism underlying the curative effect is unknown, but it may involve the interferon (IFN) system and interleukin-2 (IL-2) production. Initial studies indicated that TBI did not directly inactivate the virus, suggesting that irradiation either acted on the target cells for virus replication or on other cells mediating the effect. We have now examined the effect of this relatively low dose TBI on replication, transcription, and protein expression of the Friend virus. Northern blot analysis revealed that in FVC infected mice treated with curative low dose TBI, no spleen focus-forming virus (SFFV)-specific mRNA species were detected. Southern blot analysis revealed that a 6.0 kb SFFV fragment could be detected in infected, untreated spleen cells, but not in cells from FVC-infected mice treated with TBI, or in uninfected spleen cells. Western blot analysis revealed that the SFFV envelope glycoprotein was expressed in the spleen cells from untreated FVC infected mice, but not in the cells from TBI treated FVC infected mice. These results, consistent with our previous findings of greatly reduced spleen focus forming units in mice with FVC which had been treated with this regimen of TBI, suggest the possibility of using such treatments in other retroviral associated disorders.

Momentum and the growth-free segment of a population

In the scenario of a sudden drop in fertility to replacement level. Preston (1986) argued that the population segment under age T, the length of generation, remained growth-free. Here we first present a new relationship for the momentum of any observed population as the ratio of 1) the proportion of the observed population under the mean age at childbearing to 2) the proportion of its life table population under that mean age. We then use that relationship to demonstrate Preston's approximation. Growth factors for other population segments are also presented. When the initial population is stable, momentum can be approximated as a function of the net reproduction rate alone.

Pseudoexfoliation syndrome--case report and review of clinical features

Pseudoexfoliation syndrome is characterized by the presence of gray-white flakes on the pupillary borders and anterior lens capsule, increased trabecular meshwork pigmentation, and association with glaucoma. We describe 3 patients with this syndrome seen at Asan Meidcal Center Department of Ophthalmology in 1989, and we focus on their clinical features and management. We believe that patients with this syndrome are not as rare in Korea as has been thought, judging by scant report of cases in the past.

Ultrastructure and blood-iris barrier in experimental rubeosis iridis in rabbit

Iris neovascularization was produced in rabbits by hypotony following repeated aspiration of the vitreous. The hypotony was produced after 0.3 ml of vitreous fluid was aspirated using a 25-gauge needle through the pars plana of 10 rabbits. For the histochemical study, horseradish peroxidase(HRP) was injected through the ear lobe vein. After fixation of the iris tissue, the tissue was treated with diaminobenzidine and examined with both light microscopy and transmission electron microscopy. The newly-formed vessel was abundant, particularly on the upper stroma of the iris. The new vessel formation was evident due to the proliferation of endothelial cells, which may have been derived from preexisting iris vessels. The endothelial cells of the newly-formed vessels revealed prominent villous processes into the vascular lumen, formation of the marginal flap, numerous fenestrations in the endothelial junction, and reaction product onto extravascular space by the cytochemical electron microscopy. These results suggest that hypotony in the rabbit produces the disruption of the blood-iris barrier and the balance between angiogenesis-antiangiogenesis modulation.

Adjuvant internal hepatic radiotherapy using colloidal 32P chromic phosphate in colorectal cancer

The purpose of the study is to investigate the value of adjuvant radiotherapy given in the form of colloidal chromic phosphate 32P suspension administered via portal vein, in preventing the growth of occult metastases in the liver. Twenty two patients (10 patients of treated group with 12 controls) were followed 12 months after operation. There was no significant change in the CBC and liver functions after administration of 32P labeled colloidal chromic phosphate. Although local recurrence rates were very similar in both groups of colorectal cancer (3/12 in the control group and 4/10 in the treated group), liver metastasis rates were quite different: 4/12 in the control group and none (0/10) in the treated group. In conclusion, 32P labeled colloidal chromic phosphate is expected to prevent liver metastases of completely resected colorectal cancer.

Non-contact tonometry: an ideal method for mass screening

We evaluated one of the new non-contact tonometers, the Pulsair non-contact tonometer, to assess its accuracy and reliability. Measurements on 101 eyes were used to assess its accuracy against Goldmann tonometry measurements, and another 24 eyes were used to assess its reliability (reproducibility). The results showed the instrument to be highly accurate and reliable in measurement.

In vitro protein translocation into inverted membrane vesicles prepared from Vibrio alginolyticus is stimulated by the electrochemical potential of Na+ in the presence of Escherichia coli SecA

A protein translocation system was reconstituted from inverted membrane vesicles prepared from Na+ pump-possessing Vibrio alginolyticus and purified Escherichia coli SecA. The translocation required ATP and was stimulated by the functioning of the Na+ pump, suggesting that the electrochemical potential of Na+, but not that of H+, is important for protein translocation in Vibrio.

Systematic analysis of diuretic doping agents by HPLC screening and GC/MS confirmation

The simultaneous analysis of diuretic agents by reversed-phase liquid chromatography with a diode-array detector (DAD) was performed by using a gradient elution with acetonitrile and phosphate buffer on a Hypersil-ODS column. For the spiked urine the extraction recovery of solid-phase extraction (SPE) using Sep-Pak C18 cartridge was compared with that of liquid-liquid extraction (LLE) with diethyl ether at various pH. The standard calibration curves were linear from 0.20-20.0 micrograms/mL for all diuretic agents except amiloride, 1.0-20.0 micrograms/mL, and the detection limit was about 0.2 micrograms/mL for 3 mL of urine, except that of amiloride, which was 1.0 micrograms/mL. The confirmation analysis was performed by gas chromatography/mass spectrometry (GC/MS) following methylation. The characteristic mass fragment ions obtained by electron-impact (EI) ionization (70 eV) provided identification of each diuretic agent.

Blade size and weight effects in shovel design

The shovel is a basic tool that has undergone only nominal systematic design changes. Although previous studies found shovel-weight and blade-size effects of shovelling, the exact trade-off between the two has not been quantified. Energy expenditure, heart rate, ratings of perceived exertion and shovelling performance were measured on five subjects using five shovels with varying blade sizes and weights to move sand. Energy expenditure, normalised to subject weight and load handled, varied quadratically with the blade-size/shovel-weight (B/W) ratio. Minimum energy cost was at B/W = 0.0676 m2/kg, which for an average subject and average load would require an acceptable 5.16 kcal/min of energy expenditure. Subjects, through the ratings of perceived exertion, also strongly preferred the lighter shovels without regard to blade size. Too large a blade or too heavy a shovel increased energy expenditure beyond acceptable levels, while too small a blade reduced efficiency of the shovelling.

Analysis of corticosteroids in urine by HPLC and thermospray LC/MS

The method for simultaneous determination and confirmation of nine corticosteroids in urine by high-performance liquid chromatography with a diode array detector and thermospray liquid chromatography-mass spectrometry was studied. HPLC was performed on a C18 column with a gradient mobile phase system of water and acetonitrile. The calibration curve was linear from 20 ng/mL to 1.0 micrograms/mL for each corticosteroid, and the detection limit was 10 ng/mL in 5 mL of urine. The extraction recovery of each corticosteroid from the spiked urine was equal to or greater than 85% by liquid-liquid extraction (LLE) at pH 9 using diethyl ether and approximately 79% or more by solid-phase extraction (SPE) with a Sep-Pak C18 cartridge. The mass spectra obtained with the positive ion mode showed protonated molecular species [M + H]+, ammonium adduct ion [M + NH4]+, [MH-60]+, [MH-30]+, and [MH-18]+. The LC/MS detection limits ranged from 10 to 50 ng in the scan mode and from 1 to 5 ng in the selected ion monitoring (SIM) mode.

Functional consequences of phospholipase A2 activation in human monocytes

Human monocytes release arachidonic acid upon stimulation with a variety of soluble or particulate agents. These include: phorbol esters (i.e., 12-O-tetradecanoate phorbol-13-acetate, TPA), calcium ionophores (ionomycin), serum-treated zymosan (STZ) concanavalin A (Con A), and, to a minor degree, lipopolysaccharides (LPS). Protein Kinase C activation or increased intracellular Ca2+ are common features of the actions of most, if not all, of these stimuli. Prevention of PKC activation by the use of staurosporine or chelation of extracellular calcium by EGTA selectively impaired AA release, indicating that PLA2 may be regulated by either pathway concurrently. The generation of inositol phosphates and diacylglycerol by the action of phospholipase C, notably upon interaction with opsonized particles during phagocytosis, apparently constitutes the physiological correlate of stimulation via these agents. Release of arachidonic acid by the action of PLA2 or other phospholipid hydrolyzing enzymes leads directly to the formation of cyclooxygenase products. In the presence of markedly elevated calcium concentrations, 5-lipoxygenase (LO) is activated as well, leading to the formation and release of leukotrienes. Agents which stimulate AA release also initiate other monocyte functions, including generation of reactive oxygen intermediates and lymphokine release. This observation makes it tempting to implicate PLA2 activation in many aspects of monocyte physiology. However, no correlation with PLA2 activation and either superoxide or lymphokine release was found when multiple stimuli, including TPA, ionomycin, serum-treated zymosan, concanavalin A, or LPS, were compared simultaneously. Instead, our results indicate that PLA2 activation is regulated by the same mechanisms, including PKC activation and increased Ca2+, as are other enzymes which determine expression of monocyte function. Phospholipase A2 (PLA2) hydrolyzes fatty acid from the sn-2 position of a wide variety of phospholipids. Substrates for this (these) enzyme(s) include species which contain a variety of polar head groups (choline, serine, ethanolamine, etc.) and some phospholipids with either linkages in sn-1. In many cell types, including human monocytes, phospholipase A2 commonly acts on substrates containing arachidonic acid (AA). The liberation of free arachidonate is a first step in the metabolism of prostaglandins, hydroxyeicosatetraeinoic acids, (HETE'S), and leukotrienes (Lt's). Monocytes and macrophages have been shown to be rich sources of arachidonate and its metabolites. Some biologic properties of monocytes, notably their role as immunomodulating cells, have been attributed to eicosanoid production and release. Accordingly, much of the interest regarding PLA2 in human monocytes centers on this aspect of their function.(ABSTRACT TRUNCATED AT 400 WORDS)

Submucosal lymphatic cyst of the stomach--a case report

A submucosal lymphatic cyst is a thin-walled cyst, lined by flattened lymphatic endothelium, containing thin serous fluid. It rarely causes clinical symptoms, and it is incidentally discovered during fiberoptic panendoscopy or radiologic study in most cases. It is an extremely rare benign tumor of the stomach; however, a submucosal lymphatic cyst should be considered if a pliable and benign submucosal lesion is detected during fiberoptic panendoscopy. We report a case of submucosal lymphatic cyst of the stomach which showed a typical clinical picture. This report is the first case of submucosal lymphatic cyst of the stomach in Korea to the best of our knowledge.

Early sexual activity among adolescents in small towns and rural areas: race and gender patterns

A 1987 survey of 758 eighth-grade students from three rural counties in Maryland revealed that 61 percent of males and 47 percent of females have engaged in sexual intercourse, and that 77 percent of black students and 40 percent of whites have ever had intercourse. A logistic regression analyzing the effects of race and gender shows that the odds that young black teenagers would have had intercourse are over five times those for whites, and that the odds for males are about twice those for females. The introduction of developmental, individual, academic and behavioral factors into the regression model has little effect on these odds ratios. Separate logistic analyses of four subgroups--white males, white females, black males and black females--reveal no consistent associations between sexual activity and the factors examined. For example, such types of problem behavior as cigarette smoking and use of alcohol or certain other drugs are associated with the likelihood of sexual activity, but the specific type of behavior involved differs by subgroup: Cigarette smoking is related to an increased likelihood of sexual activity just among white females, while alcohol consumption is associated with sexual experience among black females and white males only. Use of drugs other than marijuana or alcohol is linked to a 5-9 times greater risk of sexual activity among whites, but not to any significantly increased risk among blacks, whereas living in a town (rather than in the country) is significantly associated with the likelihood of sexual intercourse among both white and black males, but not among females of either race.(ABSTRACT TRUNCATED AT 250 WORDS)

Multiple rhabdomyoma of the heart presenting with a congenital supraventricular tachycardia--report of case with ultrastructural study

A case of congenital rhabdomyoma of the heart in a 5-month-old Korean infant is described. The patient presented with a congenital supraventricular tachyarrhymia that was detected in utero by fetal sonography. The tumor was multiple, but no obvious association with tuberous sclerosis complex was demonstrated. Microscopic examination revealed classic "spider cells" with rich glycogen content. Ultrastructurally, the cells contained numerous leptofibrils, clumped Z band material, and desmosome-like cell junctions. The case is a second documented case of cardiac rhabdomyoma in this country, and its presentation as an etiological factor of supraventricular tachycardia is a very unusual manifestation.

Occupational asthma and IgE antibodies to reactive dyes

Reactive dyes have been widely used in recent years. This paper reports nine cases of immediate type occupational asthma to reactive dyes in one dye industry. All patients had had asthmatic symptoms, four had had rhinitis and they had worked for 6 to 25 months. Skin prick tests with reactive dyes were positive and bronchoprovocation tests also produced immediate or dual types of bronchoconstriction. We used the radioallergosorbent test (RAST) technique with nitrocellulose filter paper as a solid phase to detect specific IgE to four reactive dye-human serum albumin conjugates. High specific IgE binding was found in eight asthmatic workers compared with 13 negative controls. The RAST inhibition test revealed that there was no immunological cross-reactivity between 4 reactive dyes. These results suggested that the mechanism of their asthmatic symptoms was immunological, mostly an IgE-mediate reaction.

[Mercury contents in hair of dental personnel and evaluation of various agents suppressing mercury vaporization]

The purpose of the present study was to determine the mercury contents in the hair of 44 dentists and 55 hygienists as dental personnel compared with 37 male and 35 female as controls, total 171 persons in Daegu City, to compare disposable capsule with reusable capsule in their ability to suppress mercury vapour leakage during trituration and opening the capsule, and to test 4 agents (water, detergents, developer, fixer) used to suppress mercury vaporization. The results were as follows: 1. The hair mercury contents of the dental personnel (6.69 +/- 4.01 ppm) were significantly higher than those of the controls (3.03 +/- 1.62 ppm) (p less than 0.01). 2. The hair mercury contents of the hygienists (7.01 +/- 4.48 ppm) were slightly higher than those of the dentists (6.22 +/- 3.40 ppm) but not significant difference (p greater than 0.05). But hair mercury contents in the dentists and hygienists of the same period of year of exposure were 5.22 +/- 1.87 ppm, 7.01 +/- 4.48 ppm, respectively, so hair mercury contents of the hygienists were significantly higher than those of the dentists (p less than 0.05). 3. In the controls, hair mercury contents of the male (3.48 +/- 1.56 ppm) were significantly higher than those of the female (2.56 +/- 1.60 ppm) (p less than 0.05). 4. There was no correlationship between the hair mercury contents of hygienists and the period of year of exposure (r = 0.0062, p greater than 0.1) but significant correlationship in dentists (r = 0.5410, p less than 0.002). 5. Disposable capsule exhibited mercury vapour leakage during trituration and opening the capsule, 0.80 microgram, 1.97 microgram, respectively so opening the capsule was increased by 2.5 times. Reusable capsule exhibited mercury vapour leakage during trituration and opening the capsule, 0.94 microgram, 7.26 micrograms, respectively so opening the capsule was increased by 7.8 times. 6. Compared with reusable capsule, disposable capsule suppressed mercury vapour leakage during trituration and opening the capsule 1.2 times, 3.7 times, respectively. 7. Of various agents used to suppress mercury vaporization, 0.56 microgram of mercury in fixer, 0.81 microgram of mercury in developer, 0.94 microgram of mercury in detergent, 1.38 microgram of mercury in mater were released and mercury vaporization was suppressed in fixer compared with air by 12.7 times, with water by 2.5 times.

Components of change in adolescent fertility, 1971-1979

This article disaggregates change in adolescent fertility between 1971 and 1979 into four components: change in marriage patterns, in nonmarital sex, in pregnancy, and in birth. It also assesses quantitatively the relative contribution of each component to the change over time in two fertility outcomes: the probability of a nonmarital live birth and, given a live birth, the odds of its being nonmarital. The changes in the probability of sexual debut prior to marriage and in marriage patterns themselves are the two most important contributors to these changes. The influence on the change in adolescent fertility outcomes of the decreased likelihood of marriage following a nonmarital pregnancy was compensated for by the increased use of abortion to terminate the pregnancy.

Biosynthetic response of cartilage explants to dynamic compression

The biosynthetic response of calf articular cartilage explants to dynamic compression was examined over a wide range of amplitudes, waveforms, and frequencies. Glycosaminoglycan synthesis was assessed by 35S-sulfate incorporation, and amino acid uptake and protein synthesis were assessed by 3H-proline incorporation. Two culture chambers were designed to allow uniaxial radially unconfined compression and mechanical testing of cartilage disks: one chamber was used inside a standard incubator; the other was used with a mechanical spectrometer and allowed load and displacement to be monitored during compression. Dynamic stiffness measurements of 3-mm diameter disks identified a characteristic frequency [0.001 Hz (cycles/sec)] that separated low- and high-frequency regimes in which different flow and deformation phenomena predominated; e.g., at 0.0001-0.0001 Hz, significant fluid was exuded from cartilage disks, whereas at 0.01-1 Hz, hydrostratic pressure increased within disks. At the higher frequencies, oscillatory strains of only approximately 1-5% stimulated 3H-proline and 35S-sulfate incorporation by approximately 20-40%. In contrast, at the lower frequencies (a) compressions of less than 5% had no effect, consistent with the dosimetry of biosynthetic inhibition by static compression (approximately 25% compression caused a approximately 20% inhibition of radiolabel incorporation), and (b) higher amplitudes (cycling between disk thicknesses of 1.25 and 0.88-1.00 mm) stimulated 3S-sulfate incorporation by approximately 20-40%, consistent with the kinetics of response to a single 2-h compression and release. None of the compression protocols was associated with detectable alterations in (e.g., compression-induced depletion of) total glycosaminoglycan content. This study provides a framework for identifying both the physical and biological mechanisms by which dynamic compression can modulate chondrocyte biosynthesis. In addition, the culture and compression methodology potentially allows in vitro evaluation of clinical strategies of continuous passive motion therapy to stimulate cartilage remodeling.

Fluorometric assay of DNA in cartilage explants using Hoechst 33258

A simple two-step fluorometric assay of DNA in cartilage explants, utilizing the bisbenzimidazole dye Hoechst 33258, is described. Cartilage explants were prepared for assay by digestion with papain. Aliquots of the digest were mixed with dye solution, and the fluorescence emission measured. The enhancement in fluorescence of dye was specific for DNA, as demonstrated by 97% sensitivity to DNase and resistance to RNase. In addition, little or no interference was caused by non-DNA tissue components, since DNA caused an equal enhancement in fluorescence independent of the presence of papain-digested cartilage. By performing the assay on isolated chondrocytes, the cellular content of DNA was computed to be 7.7 pg per chondrocyte. The assay was stable for at least 2 h and sensitive to as little as 6 ng of DNA or equivalently less than 1000 cells. This procedure offers advantages over other established DNA assays of cartilage and may be especially useful in metabolic studies of cartilage explants.

Two domains at the origin are required for replication and maintenance of broad-host-range plasmid R1162

Two domains at the replicative origin of broad-host-range plasmid R1162 are required in cis for plasmid maintenance in Escherichia coli and for plasmid DNA replication in cell extracts. Increasing the distance between the domains reduces replication in vitro, without substantially changing plasmid DNA content or stability in vivo.

Molecular cloning and differential expression of somatic and testis-specific H2B histone genes during rat spermatogenesis

We have cloned cDNA of a testis-specific histone, TH2B (a variant of H2B), and rat somatic H2B gene to investigate regulation of testis-specific histone genes during rat spermatogenesis. The amino acid sequences deduced from DNA sequences show extensive sequence divergence in the N-terminal third of the two histones. The rest is highly conserved. One cysteine residue was found in TH2B. No cysteine is present in somatic histones except in H3 histone. We investigated the expression of TH2B and H2B genes using the regions of sequence divergence as hybridization probes. The TH2B gene is expressed only in the testis, and the expression of this gene is detected 14 days after birth, reaching a maximum at Day 20. The level of H2B mRNA shows a reciprocal pattern. This contrasting pattern can be explained by the gradually changing proportion of spermatogonia and spermatocytes with testicular maturation. In situ cytohybridization studies show that H2B gene is expressed primarily in proliferating spermatogonia and preleptotene spermatocytes, whereas TH2B gene is expressed exclusively in pachytene spermatocytes which first appear in testis about 14 days after birth. H2B and TH2B genes appear to be ideal markers for the study of proliferation and differentiation events in spermatogenesis and their regulatory mechanisms.

The association between malnutrition and diarrhoea in rural Bangladesh

The interaction between diarrhoeal disease and nutritional status measured by anthropometry was investigated in approximately 1000 children aged 1 to 4 years during April-December 1976 in a rural area of Bangladesh. Data on diarrhoeal disease were provided by the mothers interviewed at seven-day intervals. Weight and height data were collected bimonthly. Children classified using anthropometric criteria--weight-for-age, height-for-age, and weight-for-height--were prospectively evaluated for incidence and duration of diarrhoea during a short (two-month) period and a long (eight-month) period. Incidence of diarrhoea was not found to be related to nutritional status measured by any of the anthropometric criteria for any of the periods. But duration of diarrhoea was found to be related consistently to nutritional status measured by weight-for-age and weight-for-height. Diarrhoea in the short term affected weight increment in the short term, but not in the long term and did not affect height increment for any of these periods. Diarrhoea in the long term affected both weight increment and height increment in the long term.

The 20 bp, directly repeated DNA sequence of broad host range plasmid R1162 exerts incompatibility in vivo and inhibits R1162 DNA replication in vitro

The broad host range plasmid R1162 contains a directly repeated, 20 bp DNA sequence in the region of the plasmid required in cis for replication and maintenance. This sequence has been chemically synthesized and cloned, and shown to be sufficient for expression of plasmid incompatibility. The sequence also inhibits replication of R1162 DNA in a cell-free system. The strengths of both these effects are determined by the number of direct repeats (DRs) present, and are also affected to similar degrees by different mutations within the repeated sequence. Several of the mutations were tested for their effect in cis on plasmid maintenance in the cell, and one was found to cause an increase in plasmid copy number. The results suggest that the direct repeats exert incompatibility by inhibiting DNA replication, presumably because they are the binding sites for a limiting essential protein.

Dynamics of populations with changing rates: generalization of the stable population theory

A general and complete exposition of the dynamics of populations with changing vital rates is given in the discrete time formulation. Results obtained are stronger than Lopez's or Hajnal's. In addition to the proof of existence of limits, an explicit expression for the age distribution is obtained by considering forward products of population projection matrices, while an explicit expression for the generalized reproductive values is obtained by considering backward products. The forward and backward characteristic equations respectively determine the forward and backward growth rates. The relative age distribution is compared to the alternative expression of Y.J. Kim (1986, Demography 23 (3), 451-461), which is the discrete version of S.H. Preston and A.J. Coale (1982, Pop. Index 48 (2), 217-259).

The effectiveness of smoking cessation advice given during routine medical care: physicians can make a difference

Physicians may be hesitant to advise their patients to give up cigarette smoking partly because they doubt their own effectiveness. The three studies cited in this paper indicate that physicians can help their patients quit smoking if they briefly explain the benefits of quitting and provide concrete advice on how to go about it. This advice is effective primarily with light smokers. If smokers require medical care at least as frequently as nonsmokers and if physicians advise them (during routine care) to quit smoking, some 38 of the 54 million smokers could be reached in a single year. Further research is needed in areas such as physician motivation and the provision of information on smoking.

Examination of the generalized age distribution

The formula for the age distribution and other relationships that follow from it for any (non-stable) population presented by Preston and Coale are significant contributions to demography. The formulas summarize the relationships among various demographic measures precisely, and are formally analogous to the relationships that hold for stable populations. The significance of these formulas cannot be overstated; they allow us to understand clearly the relationships among demographic measures in any arbitrary population. However, when it comes to using them for estimating demographic measures when census data are defective, the method of estimation is still affected by defective data. The reason is that the series of age-specific growth rates reflects the observed census age distributions exactly so that any defects in the census data are summarized in the growth rates. This paper begins with the formulation of the discrete version of the "new synthesis" developed by Preston and Coale. With the discrete formulation, the three kinds of errors introduced when the continuous time formulas are applied to real data can be avoided. Then it is pointed out that when two accurate census data are available, the Preston-Coale procedure of "estimating" the age distribution at the second census is equivalent to checking the identity of the age distribution formula. Also "estimating" mortality by the procedure of Preston-Coale is shown to be equivalent to obtaining mortality directly from intercensal survival rates. That the procedure which involves the age-specific growth rates is equivalent to those that involve the intercensal survival rates may have escaped notice because there are no a priori constraints for patterns of age-specific growth rates to follow. The irregularity in growth rates due to defective data are not distinguishable from true irregularity that exists in the population, contrary to the well-known regularity in the pattern of survival rates in human populations.

The impact of the Mississippi Improved Child Health Project on prenatal care and low birthweight

A quasi-experimental, nonequivalent control group design was used to evaluate the Improved Child Health Projects in northwest Mississippi (ICHP1 and ICHP2). Control counties were selected for each project that on average were similar to ICHP counties on racial composition, median family income in 1970 and 1980, and number of births in 1978-79. The study population comprised all resident births in the ICHP and control counties during a pre-ICHP period (1975-78) and the ICHP period (1979-81). The percentage of women with adequate prenatal care rose between the two periods for all counties; the rise was greater for the study than for the control counties for ICHP1; the reverse was found for ICHP2. For both projects, the low birthweight rate remained constant in the pre-ICHP and ICHP periods for the study and control counties. Adjustment for changes in the childbearing characteristics between the two periods did not alter these results. Community involvement in its development and coordination may explain ICHP1's impressive rise in the use of prenatal care.

Alternative anthropometric indicators of mortality

The ability of anthropometric indicators, weight-for-age, height-for-age, weight-for-height, weight velocity, and height velocity to discriminate mortality during a one-year period is examined for three time frames beginning in different seasons. Data on approximately 1,000 children of one to four years of age come from the Matlab, International Centre for Diarrhoeal Disease Research, Bangladesh. The indicators' mortality-discriminating power is assessed in terms of the magnitude of difference between the mean indicator values of living and dead children expressed in standard deviation units and of the maximum sum of sensitivity and specificity. The indicators' mortality curve by nutritional status shows the discriminating power visually; the t test indicates its statistical significance. Weight-for-age and height-for-age perform better than weight velocity and height velocity as discriminators of mortality during a one-year period. The ability of weight and height velocity to discriminate short-term mortality is examined by comparing the mean velocity of the last two bimonthly intervals of the dead children. Weight velocity is likely to be a good indicator of short-term mortality.

On the dynamics of populations with two age groups

By restricting the number of age groups to two and by introducing continued fractions, the dynamics of populations with deterministically changing vital rates are completely specified at all times. Explicit expressions for the sequence of the product of population projection matrices are given. From these, relative age distribution and reproductive values to any desired accuracy are obtained as functions of the vital rates. Thus, the results given in this paper are stronger than any existing weak ergodic theorems.

Declines in nonwhite and white neonatal mortality in Mississippi, 1975-80

Linked birth and death records provided the population for an investigation of declines in nonwhite and white neonatal mortality rates (NMR) in Mississippi between 1975 and 1980. The effect of changes in the characteristics of women giving birth and in perinatal care on declining NMRs was analyzed. A decomposition of the difference in the 1975-76 and 1979-80 NMRs was performed to determine whether declines in NMRs were due to shifts in population characteristics or in characteristic-specific rates. Between 1975 and 1980, the NMR declined significantly by 1 death per 1,000 live births per year among nonwhites and by 0.8 per 1,000 among whites. Increases in the number of prenatal visits during the study period were associated with part of this decline, especially for nonwhites. The effect of rising use of prenatal care on NMRs was not, however, a result of shifts in the birth weight distribution. The decrease in NMRs was also associated with declining birth weight-specific rates; 75 percent of the decrease in rates was noted among low birth weight infants. Shifts in the distribution of birth weight and in maternal characteristics had little effect on declining NMRs. A strong commitment of the Mississippi State Board of Health to provide prenatal care to indigent women may be responsible for the large increases in use of prenatal care among Mississippi women. The decline in NMRs among low birth weight infants is likely linked to greater availability of specialized care for the sick neonate, although survival of these infants increased across the State, even where specialized care was not available.

Oral contraception in Bangladesh

In rural Bangladesh, the continuation rate of oral contraceptives (OCs) is the lowest among all methods except for condoms, and the pregnancy rate for OC users is comparable to that for users of traditional methods, which lies halfway between that for foam and condom users (high) and Depo-Provera and IUD users (low). To determine why postpartum amenorrheic OC acceptors have shorter pregnancy intervals than postamenorrheic OC acceptors who were matched on time of acceptance as well as on age and parity, subintervals of the pregnancy interval are examined. Results reveal significantly shorter duration of use by amenorrheic acceptors. This short duration of use overrides their significantly longer duration to pregnancy since discontinuation, to give overall shorter duration to pregnancy since last birth.

Effects of physician counseling on the smoking behavior of asbestos-exposed workers

Physician antismoking advice has been shown to increase smoking cessation, particularly among patients who have medical problems or perceive themselves to be at risk. The present study tested three hypotheses: (a) providing 3 to 5 min of behavioral counseling regarding a cessation strategy would be more effective than simply warning the smoker to quit smoking; (b) smokers with abnormal pulmonary function would be more likely to comply with medical advice than would smokers with normal pulmonary function; and (c) that smokers with abnormal pulmonary function who receive behavioral counseling would be the group most likely to achieve prolonged abstinence. Asbestos-exposed smoking men undergoing screening in a mandated program for naval shipyard workers were categorized as having normal or abnormal pulmonary status on the basis of chest X ray and pulmonary function tests (PFT). They were then randomly assigned within PFT categories to receive either a simple warning or 3 to 5 min of behavioral cessation counseling from the physician who gave them the results of their pulmonary tests. Subjects' smoking status was evaluated at 3- and 11-month intervals following the physician intervention. Smokers who received behavioral counseling were more likely to quit and remain abstinent over the 11-month period (8.4% abstinent) than were smokers given a minimal warning (3.6% abstinent). Prolonged abstinence rates among abnormal PFT subjects (3.7%) did not differ from those of normals (5.9%). The group with normal PFT who received behavioral counseling achieved the highest level of abstinence (9.5%). Maintaining adequate physician compliance with the counseling protocol proved difficult; implications of this for future efforts are discussed.

Decomposition of the difference between two rates with hierarchical factors

A decomposition method for the difference between two rates when data are classified by two factors, one of which may be considered as a more direct factor than the other for the event under consideration, is presented in this paper. The two factors are treated as hierarchical and thus this method is conceptually different from the decomposition methods of Kitagawa (1955) and Das Gupta (1978), in which two factors are treated as symmetrical. Our method is shown to be a balanced version of the Cho-Retherford (1973) decomposition method. Analyses of neonatal mortality rates using our method are presented as an example.

Nuclear localization and phosphorylation of three 25-kilodalton rat stress proteins

The nuclear localization and phosphorylation of three 25-kilodalton rat myoblast stress proteins were examined. Data obtained in these analyses led to the following conclusions: (i) all three proteins become localized in the nucleus of stressed cells, (ii) two of the proteins are modified by phosphorylation, and (iii) phosphorylation occurs exclusively on serine residues.

Sources of prescription contraceptives and subsequent pregnancy among young women

For more than four in 10 teenage women who first obtained a prescription contraceptive from a private doctor or family planning clinic prior to pregnancy, marriage or interview in 1979, that method was the first they had ever used. Whites were over two times more likely to have previously used a nonprescription method than were blacks. Blacks, on the other hand, were two times more likely than whites to have been virgins before first using a prescription method. Slightly more than half of all young women who used a prescription method first obtained it from a family planning clinic, and the remainder got it from a private physician. Blacks were much more likely to have gone to a clinic than were whites. Nine in 10 of those who obtained a prescription method chose the pill. Among blacks, there was no appreciable difference between those who got the method from a clinic and those whose source was a private doctor. Whites who obtained their method from a private doctor, however, were somewhat more likely to choose the pill than were those who got it from a clinic. Of all who had been sexually active before ever using a prescription method, about eight out of 10 whites, but only about five in 10 blacks, had previously used a nonprescription method. Overall, there was an interval of about one year between first intercourse and the time the young women first got a prescription method. Among whites, there was no difference in parental education or family stability between clinic and private physician patients.(ABSTRACT TRUNCATED AT 250 WORDS)