The origin and significance of macrophages in thoracic duct lymph.

Efferent lymph collected from a thoracic duct fistula initially contains no macrophages. However, the surgical procedures used to insert plastic cannulae into efferent lymphatics incite a vigorous foreign body reaction leading to the contamination of collected lymph with significant numbers of these cells. A sensitive and specific assay for the presence of macrophages in lymphocyte populations was used to quantitate the degree of contamination in rats bearing thoracic duct cannulae. The origin of some of these contaminant cells from the peritoneal macorphage population was established by adoptive transfer of labelled peritoneal cells to cannulated recipients.     

Significance of circulating toxin and antitoxin in unimmunized tetanus cases of neonates and infants

The level of circulating tetanus toxin, antitoxin and their individual influence on the outcome of tetanus cases were determined in unimmunized 125 neonatal and 39 infant cases of tetanus. PHA (passive haemagglutination) test showed 40% positive cases for toxin while its absence in the remaining cases indicated of either toxin fixation to the central nervous system (CNS) or it got neutralized by antitoxin. TN (toxin neutralization) and PHA test carried out in 46 sera samples revealed a strong positive correlation (r = 0.9) showing that 35/46 (76%) and 38/46 (82.6%) samples were positive for antitoxin, respectively. 25.4% of the neonate and infant cases and 34% of the control group had a protective serum tetanus antitoxin level. 42.5% of the paired sera from unimmunized mothers and their neonates showing nonprotective antitoxin levels suggested that a high level of antitoxin is needed for transplacental transfer, although transfer may not play a decisive role in the resistance against the disease. The presence of toxin or antitoxin in the clinical cases did not affect the outcome of the disease, although in neonates, presence of toxin was found to be a bad prognostic sign. This study explicitly advocates for the need to improve the vaccination coverage strategy.     

Adrenergic innervation of lymph nodes and the thoracic duct

By means of incubation of slices in 2% solution of glyoxylic acid distribution of adrenergic fibers in the rabbit lymph nodes and in the thoracic lymphatic duct has been studied. Adrenergic fibers get into parenchyma of the lymph nodes via two ways. The first--the perivascular, when the nervous fibers make a plexus and get into the node along the blood vessels, the second--diffuse nervous fibers get together with trabecules in between the lymphoid nodules. The distribution density of the adrenergic fibers is not the same in different groups of the lymph nodes. In the lumbar nodes it is the highest. In the lymph nodes of the cervical part the density of the sympathetic fibers is, as a rule, lower than in the lumbar, but higher than in the axillary nodes. The lowest density of th adrenergic fibers is in the mesenteric, superficial inguinal lymph nodes and in the lymph nodes, situating near the thoracic part of the aorta. In the lymphatic duct wall small amount of adrenergic fibers are revealed, they form a plexus, predominantly in the cranial part.