Sociodemographic characteristics, care, feeding practices, and growth of cohorts of children born to HIV-1 seropositive and seronegative mothers in Nairobi, Kenya

OBJECTIVES To compare sociodemographic profiles, child care, child feeding practices and growth indices of children born to HIV-1 seropositive and seronegative mothers.

METHODS

A cohort study of 234 children (seropositive and seronegative) born to HIV-1 seropositive mothers and 139 children born to seronegative mothers in Pumwani Maternity Hospital which serves a low-income population in Nairobi, Kenya from December 1991 and January 1994.

RESULTS

With few exceptions, at the time of their birth children in all three cohorts had parents with similar characteristics, lived in similar housing in similar geographical areas, had their mothers as their primary care givers, had similar feeding practices and similar growth status and patterns. However, the HIV-1 seropositive mothers were slightly younger (23.8 years vs. 25.0 years, P < 0.01), if married they were less likely to be their husband's first wife (79% vs. 91%, P = 0.02) and more likely to have a one-room house (75% vs. 63%, P = 0.04). All three cohorts had mean Z-scores in length-for-age and in weight-for-height within the normal range (>/= 2.0 Z-scores) from birth to 21 months with the exception of the length-for-age of the seropositive children at the 18-month visit. In all cohorts length-for-age became more compromised than weight-for-length, dropping to about -1.45 Z-score by 21 months; in contrast, weight-for-length dropped to about -0.5 Z-score by this age. The only statistically significant differences in growth indices among the three cohorts were between the two cohorts of seronegative children: those with seronegative mothers were less compromised in length-for-age at 1.5 months (mean Z-score = -0.19 vs. -0.48, P < 0.05) and more compromised in weight-for-length at 6 months (mean Z-score = 0.10 vs. 0.45, P < 0.05) and at 18 months (mean Z-score = -0.73 vs. -0.16, P < 0.05). 27-34% were exclusively breastfed at 1.5 months; 52-61% consumed solid foods in addition to breast milk by 2.5 months.

CONCLUSIONS

Low-income HIV-1 seropositive- and seronegative-born children were from families with similar characteristics and similar housing environments. Similar growth patterns in the cohorts suggest that the challenging environment and the choice of weaning foods had an impact on all three cohorts. The aggressive care given the children with HIV-1 seropositive mothers and their children may have reduced the progression and impact of HIV-1 disease on the growth of the seropositive children. Further research is needed to corroborate our findings to be certain that our results are not affected by loss to follow-up bias: we lost the same proportion in all three cohorts but cannot verify that the children we lost had the same growth patterns as those who remained in the study.

CDC growth charts: United States

OBJECTIVES

This report presents the revised growth charts for the United States. It summarizes the history of the 1977 National Center for Health Statistics (NCHS) growth charts, reasons for the revision, data sources and statistical procedures used, and major features of the revised charts.

METHODS

Data from five national health examination surveys collected from 1963 to 1994 and five supplementary data sources were combined to establish an analytic growth chart data set. A variety of statistical procedures were used to produce smoothed percentile curves for infants (from birth to 36 months) and older children (from 2 to 20 years), using a two-stage approach. Initial curve smoothing for selected major percentiles was accomplished with various parametric and nonparametric procedures. In the second stage, a normalization procedure was used to generate z-scores that closely match the smoothed percentile curves.

RESULTS

The 14 NCHS growth charts were revised and new body mass index-for-age (BMI-for-age) charts were created for boys and girls (http://www.cdc.gov/growthcharts). The growth percentile curves for infants and children are based primarily on national survey data. Use of national data ensures a smooth transition from the charts for infants to those for older children. These data better represent the racial/ethnic diversity and the size and growth patterns of combined breast- and formula-fed infants in the United States. New features include addition of the 3rd and 97th percentiles for all charts and extension of all charts for children and adolescents to age 20 years.

CONCLUSION

Created with improved data and statistical curve smoothing procedures, the United States growth charts represent an enhanced instrument to evaluate the size and growth of infants and children.

[Residual risk research of HIV infection after blood screening in one county in China]

OBJECTIVE

To estimate the risk of HIV infections from blood transfusions, to evaluate existing blood screening measures, and to make recommendations to improve current blood screening practices.

METHODS

Research was conducted in a county blood station. A statistical model and retrospective method were used to analyse the data.

RESULTS

Between June 1995 and March 1998, 19 blood donors tested positive for HIV antibodies and among them, 7 were repeat blood donors. Twenty - two blood recipients were identified from these 7 donors during six months, 9 are still alive today, while one patient was infected with HIV from a blood transfusion while undergoing an operation. The residual risk of the blood station using a statistical model and retrospective methods were 1/1,773 - 1/28,867 and 1/2,008 - 1/2,730 donations respectively.

CONCLUSION

The residual risk of HIV after screening in the county blood station was high. We recommend further improvements to current blood screening practices.

[Comparison between carboplatin and cisplatin plus etoposide and carboplatin plus etoposide in the treatment of small cell lung cancer.]

BACKGROUND

To evaluate the effect and toxicity of combination chemotherapy with carboplatin and cisplatin plus etoposide (CPE regimen) and carboplatin plus etoposide (CE regimen) in the treatment of small cell lung cancer (SCLC) .

METHODS

Thirty-two patients with SCLC were treated with CPE and CE regimens , and each regimen had 16 cases respectively. There were 10 retreated cases in CPE group and 7 retreated cases in CE group.

RESULTS

The total response rate (CR + PR) was 81. 3 %(13/ 16) in CPE group , and 87. 5 %(14/ 16) in CE group ( P > 0. 05) respectively. The response rate of the retreated cases in CPE group was 60 %(6/ 10) , and 42. 9 %(3/ 7) in CE group ( P < 0. 05) . The bone marrow suppression rate was 71. 9 % in CPE group and 93. 8 % in CE group ( P < 0. 05) . There were no significant differences between other toxicity in both groups ( P > 0. 05) .

CONCLUSIONS

The therapeutic effect of CPE regimen in SCLC is similar to that of CE regimen , but the bone marrow suppression rate of CPE regimen is less severe than that of CE regimen. The therapeutic effect of CPE regimen is better than that of CE regimen for the retreated cases.

[Anatomic investigation of facial canal related to middle ear surgery]

OBJECTIVE

To avoid hurting facial nerve in middle ear surgery.

METHOD

20 adult head cadavers with 40 sides tempotal bone were dissected and investigated.

RESULT

1. Prevalence of dehiscent facial nerve canal was 32.5% (13/40), while 2.5% (1/40), 27.5% (11/40), 7.5%(3/40) incidence facial nerve canal were found in the labyrinthine, horizontal, vertical segment respectively. 2. Distance between the vertical portion of facial nerve and posterior semicircular canal was 0.62-5.08(2.48 +/- 0.63) mm. Interspace between the vertical portion of facial nerve and tympanic chorda was 0-4.62 (2.12 +/- 0.76) mm at the level of tympanic ditch, while interspace between the vertical portion of facial nerve and tympanic ditch was 2.96-8.82 (5.86 +/- 1.62) mm. 3. Distance between horizontal portion of facial nerve and lateral semicircular canal was 0-3.02 (1.92 +/- 0.84) mm. Interspace between horizontal portion of facial nerve and stapedial board was 0.92-4.06(2.14 +/- 0.90) mm.

CONCLUSION

Familiarity with facial nerve procession should be favorable to decrease facial paralysis with middle ear surgery.

[Anatomical consideration for the injury of dacryocyst and nasolacrimal duct during intranasal sinus surgery]

Based on dissection and measurement on 20 adult head cadavers, there is the close relationship between lacrimal duct and lateral wall of the nasal cavity. The cells of anterior ethmoid sinus were classified into three degrees, according to the relationship between the anterior ethmoid sinus and the lacrimal sac fossa. The average distance is 6.74 +/- 1.72 mm between the nasolacrimal duct and the upper part of the uncinate process, 3.44 +/- 0.75 mm and 5.50 +/- 3.73 mm from the nasolacrimal duct to ethmoidal infundibulum and the maxillary ostium. The orifice of the duct most commonly opens under the insertion of the inferior turbinate anteriorly. To perform intranasal sinus surgery, the safest area and key operation approach were discussed.

[Determination of acetylcholine and choline in microdialysates from rat brain by high performance liquid chromatography with electrochemical detection combined with a post-column immobilized enzyme reactor]

In the present work, acetylcholine(ACh) and choline(Ch) in the microdialysates from three brain areas of anesthetized rats and from hippocampus and frontal cortex of freely moving rats were simultaneously measured by high performance liquid chromatography(HPLC) with electrochemical detection combined with a post-column immobilized enzyme reactor(IMER). This assay was based on the separation of ACh and Ch on a polymer gel column followed by passage of the effluent through an IMER, on which the separated ACh and Ch reacted respectively to give each stoichiometric yield of hydrogen peroxide, which was detected electrochemically at a platinum electrode (potential + 0.5 V versus Ag/AgCl). The tip of concentric dialysis probe was made of the semipermeable dialysis membrane of 0.22 mm in outside diameter, and the effective length inserted into rat brain was 3.0 mm. The probe was perfused at a rate of 1 microL/min with Ringer's solution which contained 10 mumol/L (for anesthetized rats) or 1 mumol/L (for freely moving rats) neostigmine, a reversible cholinesterase inhibitor, to elevate ACh level in microdialysate. Before the experiment, the recovery of the probe in vitro was measured at room temperature, and the position of the probe was checked by histological procedure at the end of the experiment. In the range of 0.2-100 mumol/L, the relation between the amounts and the peak areas was linear (r = 0.9988 for ACh and r = 0.9985 for Ch). The detection limit for ACh and Ch, at a S/N ratio of two, was found to be 50 fmol per injection. The probe recoveries(%) for ACh and for Ch were 23.2 +/- 1.4 and 34.3 +/- 3.2(mean +/- SD) respectively. The basal levels of ACh in the microdialysates from striatum and frontal cortex of anesthetized rats as well as from hippocampus and frontal cortex of freely moving rats were 212 +/- 28 and 22 +/- 4 as well as 26 +/- 4 and 83 +/- 7(nmol/L, mean +/- SD, not corrected according to probe recovery) respectively. The perfusion of high concentration K+ (100 mmol/L) through the dialysis probe induced a large increase of ACh in the microdialysates. The critical points for HPLC analysis combined with IMER were briefly discussed.

[The development of reference values for the brachial perimeter and body height in comparison with other indicators used for screening of the nutritional status]

Mid-upper-arm circumference (MUAC) based on a single cut-off value for all children under 5 years of age has been used for many years as an alternative nutritional status index for children during famines or refugee crises, and as an additional screening tool in nonemergencies. However, it has recently been questioned whether MUAC is age- and sex-independent. After reviewing the scientific evidence underlying the use and interpretation of MUAC, a WHO Expert Committee recommended a new MUAC-for-age reference for under-5-year-olds. In some settings, however, it is difficult to assess a child's age and in such circumstances MUAC-for height may be a good alternative. The height-based QUAC stick offers a simple means of adjusting MUAC cut-offs according to height, and the MUAC-for-height reference and construction and use of the QUAC stick are described in this article. Also described is the use of the receiver operating characteristic (ROC) curve method to evaluate the performance of MUAC, MUAC-for-age, and MUAC-for-height in screening malnourished children.

Improving trend of growth of Asian refugee children in the USA: Evidence to support the importance of environmental factors on growth

In order to better define the trends and patterns of growth for children of Asian refugee families residing in the USA, we studied the anthropometric data from 12 states collected by the Centers for Disease Control and Prevention (CDC) Pediatric Nutrition Surveillance System (PedNSS) from 1979 to 1993. The Asian refugee children under 5 years of age showed a progressive and significant decline in the prevalence of low height-for-age and low weight-for-age, while those nutritional indices remained stable for low income white children and black children. By 1993, the growth status of Asian refugee children was comparable with that of other ethnic groups. This marked improvement over a short period strongly suggests that the poor growth status earlier observed among recently immigrated Asian children was due to nutritional and health factors related to socioeconomic conditions, rather than to genetic factors, as is often suggested. Detailed analysis of each birth cohort born at different time periods found that low anthropometry during infancy is a strong predicator of smaller body size later in childhood.

Development of a research child growth reference and its comparison with the current international growth reference

OBJECTIVE

To better characterize childhood growth and further assess potential limitations of the current National Center for Health Statistics and World Health Organization international growth reference.

DESIGN

The LMS method was used for curve fitting to summarize the changes in height and weight distributions by 3 curves representing the skewness (L), median (M), and coefficient of variation (S). A series of polynomial regression procedures was applied to smooth the L, M, and S curves.

SETTING

Subset data from 18 states contributing clinic data to the Centers for Disease Control and Prevention Pediatric Nutrition Surveillance System were used for this research reference.

METHODS

We chose only those clinics in which the height and weight distributions of children closely matched with those of the first and second National Health and Nutrition Examination Surveys.

RESULTS

Unlike the current international growth reference, the new reference has no disjunction at 24 months of age because it is based on a single data source for children aged 0 to 59 months. The reference also better characterizes the growth for infants than the current international reference, a fact we demonstrated with data from the National Health and Nutrition Examination Surveys, Pediatric Nutrition Surveillance System 1995, and the Davis Area Research on Lactation, Infant Nutrition, and Growth studies.

CONCLUSIONS

The current National Center for Health Statistics and World Health Organization international growth reference needs to be updated. The methods used in this study will be useful to evaluate other data sets and to evaluate future modifications of growth references.

Increasing prevalence of overweight among US low-income preschool children: the Centers for Disease Control and Prevention pediatric nutrition surveillance, 1983 to 1995

OBJECTIVE

To determine whether the prevalence of overweight in preschool children has increased among the US low-income population.

DESIGN

Analysis using weight-for-height percentiles of surveillance data adjusted for age, sex, and race or ethnicity.

SETTING

Data from 18 states and the District of Columbia were examined.

SUBJECTS

Low-income children <5 years of age who were included in the Centers for Disease Control and Prevention Pediatric Nutrition Surveillance System.

RESULTS

The prevalence of overweight increased from 18.6% in 1983 to 21.6% in 1995 based on the 85th percentile cutoff point for weight-for-height, and from 8.5% to 10.2% for the same period based on the 95th percentile cutoff point. Analyses by single age, sex, and race or ethnic group (non-Hispanic white, non-Hispanic black, and Hispanic) all showed increases in the prevalence of overweight, although changes are greatest for older preschool children.

CONCLUSION

Overweight is an increasing public health problem among preschool children in the US low-income population. Additional research is needed to explore the cause of the trend observed and to find effective strategies for overweight prevention beginning in the preschool years.

Bacterial LPS and IFN-gamma trigger the tyrosine phosphorylation of vav in macrophages: evidence for involvement of the hck tyrosine kinase

We and others have previously reported that tyrosine kinases play key roles in the activation of macrophages by both bacterial lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma). However, little is known regarding the substrates of tyrosine phosphorylation that mediate macrophage activation and the resultant production of inflammatory mediators. In lymphocytes and other hematopoietic lineages, tyrosine phosphorylation of the proto-oncogene vav appears to be an essential component of cell activation. In this study, we demonstrate that both LPS and rIFN-gamma trigger the prompt, dose-dependent tyrosine phosphorylation of vav in murine RAW 264.7 macrophages. In addition, vav is physically associated with the src-related kinase hck in murine macrophages, and antisense oligonucleotides specific for murine hck block both LPS and rIFN-gamma-mediated vav phosphorylation. These findings suggest that hck probably mediates vav tyrosine phosphorylation during macrophage activation and that LPS and rIFN-gamma-mediated signaling pathways partially overlap.

[Microbore liquid chromatography with dual electrode electrochemical detection of monoamine transmitters in brain microdialysates]

In the present work, the method of microbore liquid chromatography(MLC) with dual electrode electrochemical detection (DEED) was used to determine the monoamine transmitters and their metabolites in the striatal microdialysates from the anaesthetized rats. The potentials applied on the upstream (anodic) electrode and downstream (cathodic) electrode were set at +0.72V and +0.05V versus an Ag/AgCl reference electrode respectively. The interference of the large early-eluting peaks from brain dialysate was well eliminated on cathodic detection on the basis of electrochemical reversibility of catechol compounds. The collection efficiency of catecholamine (NA, A and DA) and DOPAC, that is the ratio of their responses in downstream electrode to those in upstream, was found to be in the range of 0.690 to 0.768, thereby providing reliable identification and measurement of early elutes. MLC-DEED is one of the best methods for the determination of monoamine transmitters at trace level. To optimize separation and detection, these adaptations were made to the system with respect to the injection valve, flow rate of the pump, connections between injector, column and detector, and cell volume of the detector. The detection limit could reach 1pg or less per injection, and the amounts, at least in the range of 2-200pg, were linearly correlated with the peak areas both at anodic detection and at cathodic detection. Prior to the collection of samples the probe recovery was measured in vitro at room temperature, and the recovery (%) for NA, DA, DOPAC, 5-HIAA, 5-HT and HVA were 19.5, 18.9, 22.1, 14,6, 16.5 and 19.3 respectively. The reported concentration of each compound was corrected according to probe recovery. The basal concentration of DA and 5-HT in striatal microdialysates was 12.5 +/- 1.8 and 5.0 +/- 0.7nmol/L. The perfussion of high K+ (100 mmol/L) through the dialysis probe induced a large increase of the concentration of NA, DA and 5-HT in microdialysates, and further increase of the concentration was observed in rat postmortem. The critical points for MLC-DEED are briefly discussed.

Simultaneous determination of phenytoin and carbamazepine in human hair by high-performance liquid chromatography

Drug detection in human hair has been regarded as a potentially useful technique for therapeutic drug monitoring and for the assessment of therapeutic compliance. An isocratic high-performance liquid chromatography (HPLC) assay for the simultaneous measurement of phenytoin and carbamazepine in human hair was used to assess therapeutic compliance in a population of patients with epilepsy. After alkaline digestion, phenytoin and carbamazepine were separated on a reverse-phase column by using a mobile phase of acetonitrile/methanol/water (9:37:54) and monitored at a wavelength of 214 nm with methylphenyl-5-phenylhydantoin as internal standard. The assay was linear in the range from 0 to 66.66 ng/mg hair, and recoveries of both drugs at concentrations of 8.33, 33.3, and 66.66 ng/mg hair from the hair matrix ranged from 91.2 to 104.0%. Inter- and intraassay coefficients of variation for both drugs (assessed at three concentrations in the calibration range) were < 10%. The limits of detection for phenytoin and carbamazepine were 2.0 and 1.33 ng/mg hair, respectively.

The development of a MUAC-for-height reference, including a comparison to other nutritional status screening indicators

Mid-upper-arm circumference (MUAC) based on a single cut-off value for all the children less than 5 years of age has been used for many years as an alternative nutritional status index for children during famines or refugee crises, and as an additional screening tool in nonemergencies. However, it has recently been questioned whether MUAC is age- and sex-independent. After reviewing the scientific evidence underlying the use and interpretation of MUAC, a WHO Expert Committee recommended a new MUAC-for-age reference for under-5-year-olds. In some settings, however, it is difficult to assess a child's age and in such circumstances MUAC-for-height may be a good alternative. The height-based QUAC stick is a simple means of adjusting MUAC cut-offs according to height, and the MUAC-for-height reference and the construction and use of the QUAC stick are described in this article. Described also is the use of the receiver operating characteristic (ROC) curve method to evaluate the performance of MUAC, MUAC-for-age, and MUAC-for-height in screening malnourished children.

The development of MUAC-for-age reference data recommended by a WHO Expert Committee

Low mid-upper-arm circumference (MUAC), determined on the basis of a fixed cut-off value, has commonly been used as a proxy for low weight-for-height (wasting). The use of a fixed cut-off value was based on the observation that MUAC showed small age- and sex-specific differences. However, in 1993, a WHO Expert Committee concluded that age independence is not reflected in the true pattern of mid-upper arm growth, recommended the use of MUAC-for-age, and presented age- and sex-specific MUAC reference data developed with observations obtained from a representative sample of children in the USA aged 6-59 months. In this article, we explain the methodology for the development of these data, present age- and sex-specific growth curves and tables and discuss the applications and limitations of MUAC as a nutritional indicator. To develop the reference data, estimates were first obtained for the mean and standard deviation of MUAC for each month of age using 7-month segmental regression equations; a 5th-degree and a 3rd-degree polynomial in age was then used to describe the mean and standard deviation, respectively, of MUAC-for age. These curves show important age-specific differences, and significant sex-specific differences for boys and girls < 24 months of age. Correct interpretation of MUAC with regard to nutritional status requires the use of MUAC-for-age reference data such as those presented here.

PSK protects macrophages from lipoperoxide accumulation and foam cell formation caused by oxidatively modified low-density lipoprotein

In previous works, it has been evidenced that lipoperoxidative injury to macrophages caused by oxidatively modified low-density lipoprotein (O-LDL) plays an important role in foam cell formation, and that PSK, a protein bound polysaccharide extracted from the class Basidiomycetes Coriolus Versicolor, can protect macrophages from lipoperoxidative injury induced by tert-butyl hydroperoxide (tbOOH). In this paper PSK protection of macrophages from lipoperoxide (LPO) accumulation and foam cell formation caused by O-LDL and its action mechanism were further studied. The LPO accumulation was determined by using ACAS 570. Dynamic assay of the LPO level in eight single cells after adding O-LDL or determination of the average LPO content in a lot of cells incubated in advance with O-LDL for 12 h, both indicated that O-LDL might induce LPO accumulation in macrophages and the effects of O-LDL could be prevented by PSK. O-LDL might cause the changes of morphological structure in macrophages and the transformation of macrophages into foam cells, and the effects could also be prevented by PSK. The determination of selenium-dependent glutathione peroxidase (SeGSHPx) activities and mRNA contents of macrophages and changes of SeGSHPx activity and mRNA content after incubation with tbOOH showed that PSK might increase the SeGSHPx activity of macrophage and the enhanced SeGSHPx activity may occur at the level of gene transcription.

Investigation of fluorocarbon blowing agents in insulating polymer foams by 19F NMR imaging

Currently, there is no reliable and readily accessible technique with which the distribution and diffusion of blowing agents in rigid insulating foams can be detected and monitored. In this paper, we demonstrate that 19F NMR microscopic imaging together with 19F solid-state MAS NMR spectroscopy is ideally suited for such measurements and yield quantitatively reliable information that will be critical to the development and fabrication of optimized insulating materials with alternative blowing agents. Polystyrene (PS) and polyurethane (PU) foam samples were investigated with the objective of determining quantitatively the amount of blowing agents in the gaseous phase and dissolved in the polymer phase, and to determine and monitor the distribution of the blowing agents in aged foams as a function of time and temperature. The concentrations of the gaseous blowing agents in the cells and dissolved in the solid were simultaneously and quantitatively measured by 19F MAS NMR spectroscopy. An unfaced 1-yr-old PS foam filled with CH3CF2Cl has about 13% of total HCFCs dissolved in the solid; while there is about 24% of HCFCs in the solid of a faced 3-mos-old PU foam filled with CH3CCl2F. The data from 19F NMR imaging demonstrate that the distributions of the blowing agents in an aged foam are quite uniform around the center part (2 cm away from any edge) of a foam board; however, a gradient in blowing agent concentration was found as a function of distance from the initial factory cut edge. The effective diffusion coefficients of the blowing agents can be directly calculated from the imaging data. Quantitative diffusion constants and activation barriers were determined. Additionally, a foam treated with a second blowing agent was monitored with chemical shift selective imaging and the diffusion of the second gas into the foam and the out-diffusion of the original gas were determined.

Reversal of inhibition of reactive oxygen species on respiratory burst of macrophages by polysaccharide from Coriolus versicolor

Using a luminol-dependent, chemiluminescence assay we found tert-butylhydroperoxide to be a strong inhibitor of the respiratory burst of mouse peritoneal macrophages. However, the inhibition of respiratory burst induced by tert-butylhydroperoxide could be prevented after the interperitoneal injection of polysaccharide from Coriolus versicolor (PSK). Further investigation showed that glutathione peroxidase activity was markedly elevated in PSK-treated macrophages. After incubation with tert-butylhydroperoxide, higher activity of glutathione peroxidase was maintained in PSK-treated macrophages. These results suggest that the immunological function of macrophages is related to the activity of glutathione peroxidase. The non-specific immunopolysaccharide might protect macrophages from the damage induced by reactive oxygen species by enhancing antioxidative capacity.

Association of a change in chromatin structure with a tissue-specific switch in transcription start sites in the alpha 2(I) collagen gene

Chick embryonic sternal chondrocytes do not synthesize alpha 2(I) collagen until they are shifted by treatment with 5-bromo-2'-deoxyuridine (BrdUrd) to a fibroblastic phenotype, yet they transcribe this gene as rapidly as BrdUrd-treated cells. To examine further this transcription, the DNase I hypersensitive sites were mapped in the 5' region of this gene in chondrocytes, BrdUrd-treated chondrocytes, fibroblasts and three types of non-transcribing cells. A DNase I hypersensitive site at -200 bp, previously shown to be associated with the active transcription of this gene in fibroblasts, is not present in chondrocyte chromatin. The chondrocyte alpha 2(I) gene contains, however, a novel major hypersensitive site in the DNA region corresponding to the fibroblast intron 2, near the chondrocyte-specific transcription initiation site of this gene. This novel hypersensitive site is associated with the use of this alternate start site by chondrocytes, since it is lost when BrdUrd treatment causes these chondrocytes to switch to the initiation of transcription at the fibroblast start site. The BrdUrd-treated chondrocytes contain the same alpha 2(I) hypersensitive sites as fibroblasts, except that fibroblasts have an additional, previously unreported, site at -1000 bp.

Replication of an RK2 miniplasmid derivative in vitro by a DNA/membrane complex extracted from Escherichia coli: involvement of the dnaA but not dnaK host proteins and association of these and plasmid-encoded proteins with the inner membrane

A DNA/membrane complex extracted from a miniplasmid derivative of the broad host range plasmid RK2 cultured in Escherichia coli capable of synthesizing new plasmid supercoiled DNA in vitro was treated with antibodies that were made against or reacted with the dnaA and dnaK host-encoded proteins, respectively. Anti-dnaA protein antibody inhibited total plasmid DNA synthesis significantly and the synthesis of supercoil plasmid DNA almost completely. In contrast, anti-dnaK protein antibody and nonimmune serum had little or no effect on total plasmid DNA synthesis. Both proteins were found to be present in the inner but not outer membrane fraction of E. coli. A variety of miniplasmid-encoded proteins which had previously been found in the DNA/membrane complex have also been localized to the inner but not outer membrane fraction. These include an essential initiation protein of 32 kDa (and an overlapping protein of 43 kDa coded for by the same gene), as well as a 30-kDa protein that may be linked to incompatibility functions. Various extraction methods were used to distinguish between the associated and the integral nature of the plasmid-encoded proteins. The results demonstrated that the essential replication proteins (32 and 43 kDa) as well as the 30-kDa protein was tightly bound to the inner membrane. Computer analysis of the amino acid sequence of the 32 (and 43)-kDa protein revealed a hydrophobic region that is only half that normally required to span the membrane. Other interactions are discussed with respect to attaching this protein to the membrane.

Selection of hormone-responsive advanced breast cancer with a cytoplasmic estrogen receptor assay. Analysis of 100 cases

One hundred women with advanced breast cancer were treated with endocrine therapy alone and the clinical response was correlated with the estrogen receptor status of the tumor as determined by a fluorescent histochemical assay designed to estimate the percentage of cancer cells with high cytoplasmic estrogen binding activity. Using clinical response rates as the standards for measurement, this histochemical method showed an 84% sensitivity, a 74% specificity, a 76% positive predictive value and an 82% negative predictive value. These results indicate that the histochemical assay may serve as a supplementary means to identify hormone-responsive mammary carcinomas and as a research tool to study the biology of this group of tumors.

Differential Effects of selenium on the proliferation of human pulmonary adenocarcinoma cells and human embryonic lung diploid cells in vitro

The effect of different concentrations of Na2SeO3 on human pulmonary adenocarcinoma cells and human embryonic lung diploid cells in vitro was investigated. For human pulmonary adenocarcinoma cells, mitotic index and cell count decreased with increasing selenium concentrations. At 1 μg/mL sodium selenite, mitotic activity and growth of human lung cancer cells were partially inhibited, and the progression of human lung cancer cell cycle was partially arrested. When human embryonic lung diploid cells were treated with 1 μg/mL sodium selenite for five continuous days, cell counts of the treated group were closely parallel to those of the control group. After treating human embryonic lung diploid cells with 1-5μg/mL sodium selenite for 1-3 d, the mitotic index (MI), labeled index (LI), and average silver grain (SG) number per 20 labeled nuclei were the same as those of the control. In mixed cultures of human embryonic lung diploid cells and human pulmonary adenocarcinoma cells, treated with 3 and 5 μg/mL sodium selenite for 24 h, the lung diploid cells showed a normal fusiform morphology, whereas the lung cancer cells showed heavily vacuolated cytoplasms and distorted nuclei.