Persistence of multiple serovars of Neisseria gonorrhoeae.

Two simple mathematical models of gonococcal transmission dynamics that allow for heterogeneity within the pathogen were assessed. Models were compared for their ability to mirror the observed persistence of different gonococcal serovars over time and differential distribution within subgroups of the total population. Serotyping data collected between the periods of 1984-1988 and 1988-1990 were analyzed for differences in serovar distribution.

Gas uptake from an unventilated area of lung: computer model of absorption atelectasis.

A computer model of gas uptake from an area of nonventilated lung, such as a pulmonary lobe with an occluded bronchus or an alveolus with an occluded airway, is presented. Previous analyses have assumed that when an inert gas is present, equilibration of O2 and CO2 with mixed venous blood is sufficiently rapid to be treated as instantaneous. This is valid for insoluble gases such as N2 or He when the fractional concentration of inspired O2 (FIO2) is < or = 0.

Effect on lung volumes of oxygen concentration when breathing is restricted.

We have examined the effect of the fractional concentration of nitrogen (FIN2) on the decrease in lung volumes which occurs during restricted breathing with oxygen-nitrogen mixtures. Conscious human subjects breathed one of five gas mixtures of oxygen and nitrogen for 15 min on each of five occasions. For the final 5 min of each 15-min period, functional residual capacity (FRC) was reduced by one tidal volume, by external pressurization.

Reactions at the polymerase active site that contribute to the fidelity of Escherichia coli DNA polymerase I (Klenow fragment).

In order to study the structural principles governing DNA polymerase fidelity we have measured the rates of insertion of incorrect nucleotides and the rates of extension from the resulting mismatched base pairs, catalyzed by the Klenow fragment of DNA polymerase I. Using a combination of semi-quantitative and qualitative approaches, we have studied each of the 12 possible mismatches in a variety of sequence contexts. The results indicate that Klenow fragment discriminates between mismatches largely on the basis of the identity of the mismatch, with the surrounding sequence context playing a significant, but secondary, role.

Tubulin gene expression in maize (Zea mays L.). Change in isotype expression along the developmental axis of seedling root.

Two-dimensional gel/western blot analysis was used to characterize alpha- and beta-tubulin isotype expression along the developmental axis of the maize (Zea mays) seedling primary root. We identified four distinct alpha-tubulin isotypes and a minimum of six beta-tubulin isotypes. This analysis showed differences between the alpha- and beta-tubulin isotypes expressed in rapidly dividing tissue at the root tip and differentiated root tissues proximal to the tip.

Alpha-tubulin gene family of maize (Zea mays L.). Evidence for two ancient alpha-tubulin genes in plants.

Among 81 alpha-tubulin cDNA clones prepared from RNA from maize seedling shoot, endosperm and pollen, we identified six different alpha-tubulin coding sequences. The DNA sequence analysis of coding and non-coding regions from the clones showed that they can be classified into three different alpha-tubulin gene subfamilies. Genes within each subfamily encode proteins that are 99 to 100% identical in amino acid sequence.

Telephone modem access improves diabetes control in those with insulin-requiring diabetes.

Objective: To assess whether modem access improves diabetes control in IDDM patients.

Research Design And Methods: Forty-two patients participated in the study and were followed for 12 wk. The patients were randomly divided into two groups at baseline, a modem group and a control group.

Individual quality of life in patients undergoing hip replacement.

Quality of life (QoL) assessment is becoming increasingly important for measuring the impact of illnesses, diseases, and their treatment and for deciding priorities when allocating resources. We developed a novel method to measure QoL from the perspective of the individual patient. The schedule for the evaluation of individual quality of life (SEIQoL) was devised from the technique known as judgment analysis to measure patients' level of functioning in five self-nominated facets of life and the relative weight or importance attached to these areas.

Side chains involved in catalysis of the polymerase reaction of DNA polymerase I from Escherichia coli.

To continue our mutagenesis study of the polymerase active site of the Klenow fragment of DNA polymerase I, we have characterized new mutants with substitutions at Asp705, Glu710, and Glu883, and have investigated further the mutations in residues Arg668, Gln849, and Asp882, which showed strong Kcat effects in our previous study. To determine which step of the reaction is rate-limiting for each mutant protein, we measured the effect on the reaction rate of an alpha-thio-substituted dNTP. One group of mutants showed a substantial sulfur elemental effect, while a second group, like wild-type Klenow fragment, was unaffected by the phosphorothioate substitution.

Social indicators and the prediction of psychiatric inpatient service utilisation.

The relationship between social variables and psychiatric service use in Victoria was investigated using a social indicators approach. Indicators were developed separately for the urban and rural areas of the state using 1986 census data. Principal components analysis was employed to reduce the data.

Estimates of the frequency of chromosome abnormalities detectable in unselected newborns using moderate levels of banding.

Data on structural chromosome abnormalities identified during prenatal diagnosis were used to estimate the number of such abnormalities that would be detectable in an unselected series of newborns using moderate levels of banding (400 to 500 bands). These estimates were compared with the rates detected in nonbanded surveys of newborns. Between 1976 and 1990 prenatal diagnosis using banding techniques was carried out in our laboratory on 14,677 women aged 35 and over.

Calcitonin gene-related peptide (CGRP)-induced cyclic AMP, cyclic GMP and vasorelaxant responses in rat thoracic aorta are antagonized by blockers of endothelium-derived relaxant factor (EDRF).

The mechanism of CGRP-induced vasodilation in rat thoracic aorta was investigated using antagonists of the classical endothelium-derived vasorelaxant factor (EDRF) and comparisons with acetylcholine-induced vasodilations. The CGRP-induced relaxations of isolated rings of rat thoracic aorta were completely dependent on the presence of endothelium and were associated with increases in the levels of both cyclic AMP and cyclic GMP, the same as in our previous study using rat abdominal aorta. Maximum relaxations to CGRP, which represented 40-50% reversal of the norepinephrine-induced contractions, occurred with 100 nM CGRP.

Assessing the quality of life of the individual: the SEIQoL with a healthy and a gastroenterology unit population.

Current methods of measuring quality of life (QoL) impose an external value system on individuals, rather than allowing them to describe their lives in terms of those factors which they consider important. The Schedule for the Evaluation of Individual Quality of Life (SEIQoL) was developed to overcome such limitations. The QoL of 42 healthy attenders at an international immunization clinic was assessed using SEIQoL.

A chemical score to evaluate the protein quality of commercial parenteral and enteral formulas: emphasis on formulas for patients with liver failure.

Essential amino acids, found in abundance in high-quality dietary protein, are required daily by hospitalized patients and healthy persons to maintain the dynamic process of protein metabolism. One method for assessing dietary protein quality is by determining a diet's chemical score, ie, the ratio of a gram of the limiting amino acid in a test diet to the same amount of the corresponding amino acid in a reference diet (eg, whole-egg protein) multiplied by 100. This investigation used the chemical score to evaluate the protein quality of 9 parenteral and 17 enteral diets commonly used to feed hospitalized patients.

Mechanism of DNA replication fidelity for three mutants of DNA polymerase I: Klenow fragment KF(exo+), KF(polA5), and KF(exo-).

Inhibition of the pre-steady-state burst of nucleotide incorporation by a single incorrect nucleotide (nucleotide discrimination) was measured with the Klenow fragment of DNA polymerase I [KF(exo+)]. For the eight mispairs studied on three DNA sequences, only low levels of discrimination ranging from none to 23-fold were found. The kinetics of dNTP incorporation into the 9/20-mer at low nucleotide concentrations was also determined.

The 3'-5' exonuclease of DNA polymerase I of Escherichia coli: contribution of each amino acid at the active site to the reaction.

We have used site-directed mutagenesis to change amino acid side chains that have been shown crystallographically to be in close proximity to a DNA 3' terminus bound at the 3'-5' exonuclease active site of Klenow fragment. Exonuclease assays of the resulting mutant proteins indicate that the largest effects on exonuclease activity result from mutations in a group of carboxylate side chains (Asp355, Asp424 and Asp501) anchoring two divalent metal ions that are essential for exonuclease activity. Another carboxylate (Glu357) within this cluster seems to be less important as a metal ligand, but may play a separate role in catalysis of the exonuclease reaction.

Calcitonin gene-related peptide levels are elevated in patients with sepsis.

Calcitonin gene-related peptide (CGRP), an endogenous vasoactive peptide encoded by the calcitonin gene in nerve cells, is distributed throughout the cardiovascular system and is a potent vasodilator. Plasma levels of CGRP have been elevated in animal models with sepsis. This study was designed to determine whether plasma CGRP levels are elevated in patients with sepsis and perhaps contribute to the hyperdynamic cardiovascular state in sepsis.

Calcitonin gene-related peptide increases coronary flow and decreases coronary resistance.

Calcitonin gene-related peptide (CGRP) is a potent vasodilator, but its effects on in situ ventricular function are unknown. We studied effects of intracoronary CGRP (100, 200, and 600 pmole/min, for 10 min) in 21 open-chest chloralose-anesthetized dogs. Systemic, pulmonary, left ventricular (LVP), central venous, and pulmonary capillary wedge pressures were continuously monitored.