A quick glance at selected topics in this issue

“A quick glance at selected topics in this issue” aims to highlight selected articles and provide a quick review to the readers.     

The effects of toxoplasma infection on rodent behavior are dependent on dose of the stimulus

Parasite Toxoplasma gondii blocks the innate aversion of rats for cat urine, putatively increasing the likelihood of a cat predating a rat. This is thought to reflect an adaptive behavioral manipulation, because toxoplasma can reproduce only in cat intestines. While it will be adaptive for the parasite to cause an absolute behavioral change, fitness costs associated with the manipulation itself suggest that the change is optimized and not maximized. We investigate these conflicting suggestions in the present report. Furthermore, exposure to cat odor causes long-lasting acquisition of learnt fear in the rodents. If toxoplasma manipulates emotional valence of cat odor rather than just sensory response, infection should affect learning driven by the aversive properties of the odor. As a second aim of the present study, we investigate this assertion. We demonstrate that behavioral changes in rodents induced by toxoplasma infection do not represent absolute all-or-none effects. Rather, these effects follow a non-monotonous function dependent on strength of stimulus, roughly resembling an inverted-U curve. Furthermore, infection affects conditioning to cat odor in a manner dependent upon strength of unconditioned stimulus employed. Non-monotonous relationship between behavioral manipulation and strength of cat odor agrees with the suggestion that a dynamic balance exists between benefit obtained and costs incurred by the parasite during the manipulation. This report also demonstrates that toxoplasma affects emotional valence of the cat odor as indicated by altered learned fear induced by cat odor.     

Detection of previously unrecognized daytime desaturation in children with chronic lung disease

PRIMARY OBJECTIVE: The prime rationale of this research is to investigate the possible occurrence of previously unrecognized episodes of desaturation apparent in preterm infants with chronic lung disease as they freely move around a non-artificial environment. RESEARCH DESIGN: The study comprises 58 hours of telemetric recordings of SpO2, heart rate, body movement and temperature, along with full ECG and photoplethysmographic waveforms for eight preterm subjects in their home environment. MAIN OUTCOME/RESULTS: The data is analysed for remarkable events, more particularly periods of spontaneous desaturation. Statistical results for all case studies are collated into a table along with examples of graphical analysis. CONCLUSIONS: This study has shown that some patients are prone to episodes of hypoxemia during the course of normal daily activity or daytime sleep that would usually go unrecognized and that more effective management of supplemental oxygen treatment may be possible with continual unobtrusive monitoring.     

Surgical site abscess caused by Lactobacillus fermentum identified by 16S ribosomal RNA gene sequencing

We report the first case of surgical site abscess caused by Lactobacillus fermentum from a 53-year-old woman with squamous cell carcinoma of the esophagus after transthoracic esophagectomy and neoadjuvant chemoirradiation. 16S rRNA gene sequencing is a useful tool to better characterize the epidemiology and clinical significance of L. fermentum.     

Systemic granulomatosis and hypercalcaemia following intravesical bacillus Calmette-Guérin immunotherapy

Abstract.  Schattner A, Gilad A, Cohen J (Kaplan Medical Center, Rehovot; and Hebrew University-Hadassah Medical School, Jerusalem, Israel). Systemic granulomatosis and hypercalcaemia following intravesical bacillus Calmette–Guérin immunotherapy (Case report). J Intern Med 2002; 251: 272–277.     

A comparative study of hepatitis B viral markers in the family members of Asian and non-Asian patients with hepatitis B surface antigen-positive hepatocellular carcinoma and with chronic hepatitis B infection.

Serologic tests for evidence of hepatitis B virus (HBV) infection were performed on family members of Asian and non-Asian patients with either hepatitis B surface antigen (HBsAg)-positive hepatocellular carcinoma or chronic HBV infection. Asian family members had a significant increase of HBsAg (34% higher) and of antibody to HBsAg or of antibody to hepatitis B core antigen (50% higher) when they were compared with non-Asian family members. In the Asian group, viral markers were detected more frequently in blood relatives than in nonblood relatives of the index cases. Within this group, birthplace did not influence the frequency of antigenemia, since HBsAg was positive in 55 (44%) of 125 Asians born in Asia and in 36 (38%) of the 94 Asians who were born in the United States. Also, HBsAg positivity frequently was seen in offspring from HBsAg-positive carrier mothers as well as from HBsAg-positive carrier fathers whose spouses were either HBsAg-negative or who had antibody. The e antigen was found more often in individuals 30 years of age or younger than in older individuals. This study indicates that intrafamilial spread of HBsAg in Asian families plays an important role in the perpetuation of HBV infection and in the eventual development of chronic liver disease in this ethnic group.