The polymerase chain reaction is a central component of current molecular biology. It is a cyclic process, in each early cycle of which the template DNA approximately doubles. An indicator which ...fluoresces when bound to DNA quantifies the DNA present at the end of each cycle, giving rise to a fluorescence curve which is characteristically sigmoid in shape. The fluorescence curve quantifies the amount of DNA initially present; the more the initial DNA, the earlier the rise in the fluorescence. Accordingly the amount of DNA initially present in two samples can be compared: the sample with the less DNA gives rise to a relatively delayed fluorescence curve and the ratio of the DNAs can be deduced from the separation of the curves. There is, however, a second determinant of this separation, the fold increase in DNA per cycle: ideally a twofold increase but frequently less. Current guidelines recommend that this be determined experimentally by carrying out PCR on a series of dilutions. If the value of the fold increase is known, then the algorithm for determining the separation can be reduced to a relatively simple computation, rather than employing a multidimensional nonlinear optimization such as the Marquardt-Levenberg as currently employed.
Plasma concentrations of hepatic glutathione S-transferase (GST) are a more sensitive measure of acute hepatic damage than aminotransferase activity. Plasma GST concentrations have been measured by ...radioimmunoassay in an open randomised study after halothane or isoflurane anaesthesia. The concentration of GST was significantly increased after anaesthesia in patients who received halothane in 30% oxygen/70% nitrous oxide (n = 37) and in patients who received halothane in 100% oxygen (n = 17). The frequency of abnormal GST concentrations, defined as 4 micrograms/l or more, was 35% and 24%, respectively. GST concentrations usually reached a peak 3-6 h after the end of anaesthesia. In 17 patients who received isoflurane in 30% oxygen/70% nitrous oxide, there was no significant rise in GST concentration and no patient had a concentration above 4 micrograms/l. No patient in any of the groups had a significant increase in alanine aminotransferase. In clinically identical situations, anaesthesia with halothane but not isoflurane leads to demonstrable impairment of hepatocellular integrity.
Experimental and theoretical work studying the (e,2e) collision process from diatomic molecules is reported. In particular, recent work carried out from near threshold to ∼100
eV incident electron ...energy ionizing H
2 and N
2 in coplanar symmetric and asymmetric geometries is compared to calculations using a molecular three body distorted wave model. Of interest is the possibility of observing the effects of Young's double slit-type interference terms in the measured cross-sections. There is considerable interest in this type of scattering, since simple models predict the effects should be equivalent to a modulation of the cross-section from individual atoms which constitute the molecule. Such effects have recently been inferred at 250
eV incident energy in an asymmetric geometry, however at lower energies the complexity of the scattering process and the requirement to integrate over all possible alignments of the targets means that these effects remain unclear. Experimental data and results from a molecular three-body distorted wave (M3DW) model are presented, and possible methods to experimentally align and detect the molecular direction prior to ionization are suggested.
The complications of infection and clotting are frequent enough as to make vascular access sites and their preservation a prime consideration in the management of patients who require long-term ...maintenance hemodialysis for support of end-stage renal disease. Utilization of the described technique during placement of subcutaneous conduits on the volar surface of the forearm for hemodialysis purposes tends to minimize the complications of infection and clotting and prolong the usable life of the conduit fistulas.
This paper reports the success of outreach efforts to immunize adults at high risk of acquiring hepatitis B virus (HBV) infection. Local health department testers recruited clients when they sought ...anonymous HIV testing. Interested clients were serologically tested for HBV infection. Susceptibles were offered a free hepatitis B vaccine. Of 189 clients who were tested, 161 (86%) were susceptible to HBV infection and 140 (74%) were men who have sex with men (MSM). Of the susceptibles, 82 (51%) started the hepatitis B vaccine series. Sixty‐five (80%) received three doses of hepatitis B vaccine and an additional 10 (12%) received two doses. Completing the hepatitis B vaccine series was associated with being a MSM (odds ratio OR 8.8, confidence interval CI 1.5–56.0) and with not being an injection drug user (IDU) (OR 0.2, CI 0.02–1.0). One way to provide hepatitis B vaccine to MSM is to attach an immunization program to a successful anonymous HIV testing program. The feasibility of implementing such programs would increase if public vaccine policymakers made more federally purchased hepatitis B vaccine available for adults.
Four different β‐tubulin cDNA clones have been identified in maize pollen cDNA libraries. Three of the four cDNA clones represent new maize β‐tubulin genes that have been designated tub3, tub4 and ...tub5. It is shown that the β‐tubulin gene family in maize is more complex than originally anticipated and more complex than those in vertebrates. In the maize β‐tubulin gene family the tub3, tub4 and tub5 genes are shown to represent small β‐tubulin gene subfamilies. Differences in the abundance of the tub3, tub4 and tub5 transcripts are seen among vegetative and reproductive tissues. The tub3 and tub4 transcripts are most abundant in pollen. In spikelet development, abundance of the tub3 transcript increases markedly from the 0.7 cm to the 1.0 cm spikelets whilst the levels of tub4 transcript closely resemble those of total β‐tubulin transcript in the organs examined. The tub3 and tub4 genes appear to have diverged recently in the evolution of the maize β‐tubulin gene family. The tub5 gene is expressed in pollen but its transcript is most abundant in maize vegetative tissues.
To investigate whether living in a 3-generation household (grandmother-mother-child) is associated with fewer behavior problems and better cognitive development among preschool children of mothers ...who gave birth during adolescence and whether it protects children from the behavior and developmental problems associated with maltreatment and maternal depression.
Cohort study.
Participants included low-income families recruited from 4 sites: East, Northwest, Midwest, and South, who are part of LONGSCAN, a longitudinal study of children's health, development, and maltreatment.
One hundred ninety-four mothers who were adolescents (less than age 19) at delivery. Data were gathered when children were 4 to 5 years of age. Twenty-six percent of the children lived in 3-generation households, 39% had a history of maltreatment, and 32% of the mothers had depression scores in the clinical range.
Child behavioral problems were measured with the Child Behavior Checklist, completed by the mother, and child developmental status was assessed with the Battelle Developmental Inventory Screening Test, administered by research assistants.
Multiple regression analyses revealed that children who had been reported for maltreatment and had mothers with depressive symptoms had more externalizing behavior problems, compared with children who experienced neither risk or only 1 risk. However, when residential status was considered, children with the greatest number of externalizing behavior problems were those who experienced both maltreatment and maternal depressive symptoms and lived in 3-generation households. Children who had been reported for maltreatment or had mothers with depressive symptoms were more likely to have internalizing problems, compared with children with neither risk. Residential status was not related to children's internalizing behavior problems or cognitive development.
Living in a 3-generation household did not protect preschool children from the behavior problems associated with maltreatment and depression. In contrast, living in a 3-generation household was associated with more behavior problems among the highest risk group of children--those who had been maltreated and had mothers with symptoms of depression. Although 3-generation families may provide an important source of support and stability for adolescent mothers and their infants early in the parenting process, it may not be advisable to rely on 3-generation households as young mothers enter adulthood, particularly among those with a history of maltreatment or depression. Children with the fewest number of behavior problems were living with their mothers in their own household (often with the father), had not been maltreated, and had mothers with few symptoms of depression.
We report the case of a patient who presented with a carcinoma of her right breast with ipsilateral axillary lymph node involvement whose staging investigations were otherwise normal. In addition to ...surgery she received a course of CMF chemotherapy and tamoxifen. Within six months of the diagnosis of breast carcinoma being made, the patient presented as an emergency with widespread intra-abdominal disease from a primary hepatocellular carcinoma. We have not previously witnessed the development of a second primary malignancy in a patient who has already received medication considered to be beneficial in the treatment of both types of malignancy. An extensive literature search has failed to reveal a similar case. The question of immunosuppression secondary to treatment with CMF chemotherapy is raised, and we suggest that perhaps a simple percutaneous biopsy of apparent liver metastases be performed under ultrasound control so as to determine the origin of liver disease in patients with breast carcinoma.
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