Fourteen-Day Inhalation Study in Rats, Using Aged and Diluted Sidestream Smoke from a Reference Cigarette: I. Inhalation Toxicology and Histopathology

Sprague-Dawley rats were exposed 6 hr per day for 14 consecutivedays to aged and diluted sidestream smoke (ADSS), used as asurrogate for Environmental Tobacco Smoke (ETS), at concentrationsof 0.1 (typical), 1 (extreme), or 10 (exaggerated) mg of particulatesper cubic meter. Animals were exposed nose-only, inside whole-bodychambers, to ADSS from the 1R4F reference cigarette. End-pointsincluded histopathology, CO-ox-imetry plasma nicotine and cotinine,clinical pathology, and organ and body weights. The only pathologicalresponse observed was slight to mild epithelial hyperplasiaand inflammation in the most rostral part of the nasal cavity,in the high-exposure group only. No effects were noted at mediumor low exposures. The minimal changes noted were reversible,using a subgroup of animals kept without further treatment foran additional 14 days. Overall, the end-points used in the studydemonstrated that there was no detectable biological activityof ADSS at typical or even 10-fold ETS concentrations and thatthe activity was only minimal at very exaggerated concentrations(particle concentrations 100 times higher than typical real-worldconcentrations).     

Human papillomavirus detection in self-collected vaginal specimens and matched clinician-collected cervical specimens

Human papillomavirus (HPV) detection is an integral part of cervical cancer screening, and a range of specimen collection procedures are being tested. Preliminary studies have found that the majority of women prefer self-collection of vaginal specimens instead of clinician-collected specimens of the cervix. The purposes of the current study were to explore the social and behavioral predictors of acceptance of self-collection of vaginal specimens among patients and to assess concordance in detection of HPV between clinician-collected cervical specimens and self-collected vaginal specimens. The study was conducted at a university family medicine clinic using a cross-sectional study design, and enrollment of women presenting for routine gynecological examination consecutively in a period of 1 year, self-administered questionnaires, collection of paired vaginal and cervical specimens for HPV DNA using Hybrid Capture 2, and cytologic analysis. Most women (79.8% [398/499]) agreed to collect vaginal specimens. In our study, 76.6% (216/282) African American women (AA), 88.1% (156/176) white non-Hispanic (WNH) women, and 63.4% (26/41) women of other races (P < 0.0001) agreed to self-collect vaginal specimens. HPV was detected in 16.0% (80/499) of clinician-collected cervical specimens and 26.1% (104/398) of self-collected vaginal specimens (P < 0.001). HPV detection was concordant in 13.4% (53/398) women in both cervical and vaginal specimens. Self-collection of vaginal specimens for HPV DNA detection is acceptable to most women presenting for routine gynecological examination. WNH women were more likely to obtain self-collected specimens than AA women. Vaginal specimens were more likely to be positive for HPV than were cervical specimens.     

Fetal Growth is Associated Positively With Maternal Intake of Riboflavin and Negatively With Maternal Intake of Linoleic Acid

Objective To examine whether dietary factors in pregnancy are related to fetal growth.Design Prospective longitudinal study during pregnancy; midway through gestation a dietary history was obtained.Subjects/setting Subjects (n=372) were participants in a study on maternal essential fatty acid status during pregnancy who did not have hypertension or any metabolic, cardiovascular, neurological, or renal disorder. Only pregnant white women with the intention to give birth in one of the three hospitals involved in the study were included. All three hospitals were located in the southern part of the Netherlands.Statistical analyses performed The relation between maternal nutrition and fetal growth was evaluated using multiple regression analyses.Results Maternal intake of n-3 fatty acids plus arachidonic acid and of riboflavin were associated positively with fetal growth. A negative relation was observed between linoleic acid intake and fetal growth.Applications/conclusions Our data suggest that the maternal diet during pregnancy is associated with fetal growth. Although this relationship ought to be more closely investigated, our results imply that much more attention should be paid to an adequate maternal diet during pregnancy, especially with respect to riboflavin and fatty acid intake. J Am Diet Assoc. 1997; 97: 867-870.     

Atrial Lead Dislodgement with a DDD Pacemaker

A 48-year-old man with previous aortic valve surgery and aortic root repair had a DDD pacemaker inserted (using transvenous leads) for the treatment of complete heart block. An atrial J active fixation electrode was used. Four weeks following implantation the patient returned with an unusual electrocardiographic rhythm demonstrating two separate QRS morphologies. Both PA and lateral chest x-ray failed to demonstrate a change in lead position. The MARKER CHANNEL of the DDD pulse generator confirmed that the alternating QRS morphologies were due to atrial lead dislodgement. Although uncommon, displacement of atrial active fixation leads may occur and lead to unusual electrocardiographic rhythms. Use of a MARKER CHANNEL may aid in the diagnosis.     

Successful Radiofrequency Catheter Ablation of Sustained Ventricular Tachycardia Postmyocardial Infarction in Man Guided by a Multielectrode "Basket" Catheter

Multielectrode "Basket" Catheter. Currently, analysis of sustained ventricular tachycardia postmyocardial infarction in man is limited by the time required for single point activation mapping and the difficulty in obtaining information during hemodynamically unstable arrhythmias. To overcome these limitations, we developed a multielectrode "basket" catheter for endocardial recording and pacing. This report describes the first clinical use of such a catheter to guide successful radiofrequency ablation of incessant sustained ventricular tachycardia postmyocardial infarction. This system may significantly shorten the time required for VT analysis and improve the results of radiofrequency catheter ablation for VT postmyocardial infarction.     

Specific lgG1 and lgG2 antibody responses of dogs to Leishmania infantum and other parasites

Sera from dogs naturally infected with Leishmania infantum were analysed for the IgG subclass specificity of their antibody response by ELISA. Dogs infected with L. infantum produced both IgGl and IgG2 antibodies with IgG2 being associated with asymptomatic infections and IgGl being associated with disease (symptomatic dogs, non- or low-responsive to chemotherapy). The differential responses of IgG] and IgGl serum antibodies in asymptomatic and symptomatic dogs may indicate a dichotomous immune response to infection with L. infantum. To confirm this, on a broader scale, sera from dogs naturally exposed to an asymptomatic protozoan infection, Toxoplasma gondii, were also analysed as were sera from dogs exposed to the helminths, Dirofilaria immitis and Toxocara canis. Antibodies specific for T. gondii antigen detected in sera from 17 dogs were of the IgG2 subclass only. Both IgGl and IgG2 antibodies to D. immitis andl. canis were present in the sera of naturally infected dogs but IgGl appeared to be the predominant subclass. Furthermore, in dogs experimentally infected with T. canis, selective regulation ofIgG2 and IgGl responses was apparent since production of the two subclasses occurred at different times following infection, with IgGl levels declining as IgGl levels rose. Thus, the analysis of IgG subsets in parasitized dogs provides evidence of a dichotomous response to infection: IgGl is associated with asymptomatic protozoan infections and IgGl is associated with helminth infections and disease caused by protozoan infection.     

Swallowing-Induced Tachycardia: Electrophysiologic and Pharmacologic Observations

A 38-year-old man developed palpitations after swallowing. Intracardiac recordings and esophageal manometry were obtained during episodes of swallowing-induced tachycardia. These studies demonstrated that the site of origin of the tachycardia was the high right atrium and that the onset of the tachycardia occurred prior to the arrival of the peristaltic wave in the esophagus. Evaluation of the tachycardia revealed that the likely mechanism for the tachycardia was triggered automaticity. Autonomic blockade and other pharmacologic interventions failed to prevent episodes of tachycardia. Swallowing-induced tachycardia is a rare disorder triggered by an undefined neural reflex arc.     

RNA Metabolism in Lymphocytes Stimulated by Phytohemagglutinin: Initial Responses to Phytohemagglutinin

The initial changes in lymphocyte RNA metabolism produced by treatmentwith phytohemogglutinin (PHA) are described. The earliest change was adecrease in total RNA (i-RNA), detectable after 30 minutes of exposure toPHA. This loss could not be localized to any of the major types of cellularRNA. After 1 hour, accelerated synthesis of RNA, shown by incorporation ofu-H³, was detected, and a progressive increase in rate of synthesis continuedfor 24 hours.

The significance of the early loss of RNA as related to the onset of lymphocyte growth is discussed.

Submitted on August 7, 1964 Accepted on October 26, 1964