Search PubMed⌕ Search

Biomedical subjects

A J Gordon

Publications and source records attributed to A J Gordon.

66 records · Page 4Linked to original sources
PubMed1968

Endocardial electrograms from pacemaker catheters.

Proper placement of pacemaker catheters can be facilitated by recording endocardial electrograms from the catheters. These electrograms are also helpful in the investigation of pacemaker failure. Endocardial contact is indicated by S-T segment elevation. When bipolar catheters are used, these "contact currents" may be visible in electrograms from the tip or ring electrodes, or both. Right ventricular cavity electrograms are characterized by their high voltage and are influenced by intraventricular conduction defects and acute myocardial infarction. Serial changes have been described indicating myocardial injury, infarction, and healing in the area underlying the catheter tip.

Cardiac Catheterization↗
PubMedDate not supplied

N-methyl-N'-nitro-N-nitrosoguanidine induced DNA sequence alteration; non-random components in alkylation mutagenesis.

Our approach to the study of how the molecular nature of DNA modulates the behavior of mutational sites involves the characterisation of distributions of mutations. The Escherichia coli lacI genetic/M13 cloning system allows the comparison of base substitution frequencies at a large number of sites. The observed distribution of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced G:C----A:T transition (the predominant event), and A:T----G:C transition (a relatively rare event), is strikingly non-random. Some sites of G:C----A:T mutation are almost 100 times more often mutated by MNNG than the least susceptible sites. Sites of mutation, however, do not display a continuum of mutability, but rather can be strictly demarcated by their 5' flanking base. Sites with a high frequency of occurrence share a common sequence motif, namely 5'-R-G-N-3', which is the sole apparent feature that distinguishes them from sites less commonly mutated (i.e. 5'-Y-G-N-3'). A corollary of this defined site specificity is the absence of a strand bias in MNNG-induced lacI-d mutation. The availability of specific or non-specific alkylation-repair systems does not appear to alter the distribution of mutation, which suggests that the observed mutational distribution is a direct reflection of the initial damage distribution. MNNG does not belong to that class of compounds typified by ultraviolet light or 4-nitroquinoline-N-oxide which exhibit both random and non-random components of mutagenesis.

Alkylation↗
PubMedDate not supplied

Oestradiol applied locally to ripen the unfavourable cervix.

The unfavourable cervix in late pregnancy presents a difficult clinical problem if labour has to be induced. In an attempt to improve the outcome, the effect of applying oestradiol directly to the cervix the day before planned induction was investigated. Two groups of twenty-five primigravidas were studied, one group receiving 150 mg oestradiol in viscous gel and the other the viscous gel alone. There was a significant increase in cervical ripeness in the group who received oestradiol and a reduction both in the length of the labour and in the need to resort to caesarean section.

Adolescent↗
PubMedDate not supplied

Cefoperazone sodium in the treatment of serious bacterial infections in 2,100 adults and children: multicentered trials in Europe, Latin America, and Australasia.

Data from noncomparative multicenter trials of cefoperazone sodium in 17 countries throughout Australasia, Europe, and Latin America were analyzed. The study populations included 1,659 adults and 438 children with a wide variety of serious urinary tract infections, respiratory tract infections, and miscellaneous infections. Most adult patients received either 1 g (42%) or 2 g (53%) of cefoperazone iv twice daily for 8-10 days. Satisfactory clinical responses were achieved in 91% of 586 assessable patients with respiratory tract infections, 94% of 571 with urinary tract infections, and 93% of 301 with miscellaneous infections. Organisms resistant to most cephalosporins, including Pseudomonas aeruginosa, other Pseudomonas species, Enterobacter, indole-positive Proteus, Serratia, Bacteroides fragilis, and Streptococcus faecalis (nonendocarditis infections) responded to cefoperazone treatment. Ten percent of patients reported one or more adverse effects directly attributable to cefoperazone, most of which were mild or moderate in severity. In a global evaluation that took into account baseline disease severity, clinical and bacteriological outcome, and toleration, investigators judged cefoperazone as excellent or good in 83% of patients, fair in 10%, and poor in 7%. The usual dosage for pediatric patients was 25-50 mg/kg two or three times daily for about seven days. Overall clinical effectiveness in 417 assessable patients was 89% for a wide variety of infections. Ten of 11 cases of meningitis were cured. Mild adverse reactions were reported for 14 patients. The results indicate that cefoperazone sodium is a safe and effective antibiotic for use in adults and children with serious bacterial infections.

Adolescent↗