IL-1 plays a critical role in oral, but not dermal, wound healing.

Wound healing is a well-orchestrated complex process leading to the repair of injured tissues. After injury, proinflammatory cytokines act as important modulators of the inflammatory process. IL-1 expression has been regarded as necessary for healing; however, its effects have also been implicated in delayed wound repair. Currently, there is no consensus or direct evidence that IL-1 activity plays a central role in the healing process. The present investigation was undertaken to define the role of IL-1R signaling in the healing outcome of an excisional wound in the palate or scalp of mice that had targeted deletions of the IL-1R type 1 (IL-1R1(-/-)) compared with matched wild-type mice. Histomorphometric analysis was undertaken to assess the degree of healing and the recruitment of polymorphonuclear and mononuclear phagocytes. After 14 days, wild-type mice exhibited complete closure of intraoral wounds, while IL-1R1(-/-) animals had only partial closure (50%). In the IL-1R1(-/-) mice, healing tissues exhibited a persistent inflammatory cell infiltrate, which did not occur in wild-type animals. Treatment with antibiotics significantly diminished the persistent inflammatory infiltrate and improved healing in the experimental animals. In contrast to oral wounds, the rate of healing and recruitment of polymorphonuclear cells in scalp wounds was similar in IL-1R1(-/-) and wild-type mice. The present data underscore the importance of IL-1 in wound healing in a challenging environment and identify its principal role in facilitating the healing process by protecting an open wound from bacterial insult. In a less challenging environment, the production of new connective tissue and its coverage by migrating epithelium are minimally affected by the absence of IL-1 activity.     

Effects of hypoxia on megakaryocyte size and number of C3H and BALB/c mice.

In an effort to explain the different platelet production capabilities of both normal and hypoxic male and female C3H and BALB/c mice, megakaryocyte size and number were determined utilizing bone marrow from both normal and hypoxic mice. The results indicate that normal BALB/c female mice have increased numbers of megakaryocytes, but of smaller size compared with either BALB/c male mice or to both sexes of C3H mice. An inverse relationship between the size and number of megakaryocytes was found in both normal and hypoxic mice; therefore, to evaluate total megakaryocyte characteristics, we calculated total megakaryocyte masses (TMM). With hypoxia, megakaryocyte number decreased, whereas megakaryocyte size increased. Despite the increase in megakaryocyte size, hypoxia caused a significant decrease in TMM (P less than 0.005) in all mice, but female C3H mice had higher TMM (P less than 0.05) than did female BALB/c mice. These data show that hypoxia decreases TMM in mice, and that the effect is greater in C3H mice than in BALB/c mice.     

Effects of starvation and sucrose feeding on corpora allata of last instar larvae of Manduca sexta: in vitro activity, size, and cell number

Abstract Larvae of the tobacco hornworm moth Manduca sexta starved for the first 3 days of the last (fifth) stadium undergo a supernumerary moult. If they are provided with sucrose during the starvation period, they develop into normal pupae although pupation is delayed. The activities of the corpora allata (CA) from normal, starved, and sucrose fed larvae were followed through the fifth stadium with a radiochemical assay for Juvenile Hormone (JH) biosynthesis. An attempt was made to correlate CA-activity with CA cell number, size, and protein content.
In CA of normally fed larvae the rate of JH synthesis declined to undetectable levels by day 4 which was also the time of exposure of the dorsal vessel. In CA of starved larvae, the rate of JH synthesis at first decreased but began to increase on day 3 and reached a peak value by day 7 , at which time head capsule slippage occurred. In CA of sucrose fed larvae, the rate of biosynthesis declined as in normal larvae but the decline was extended over a longer period. Exposure of the dorsal vessel was delayed in the same manner and occurred on days 7–9. The major JH in all cases was JH-II.
The CA comprise c. 150 cells in the early fifth stadium, and this number remained constant during the fifth stadium in all three feeding regimens. In normal larvae, CA size and protein content increased several-fold during the stadium whereas in starved and sucrose-fed larvae they increased slowly and in agreement with the altered timing of developmental events. In none of the groups was the CA activity pattern correlated with morphometric changes of the CA. The rates of JH biosynthesis were not closely correlated with published JH titre curves. The in vivo mechanisms for regulation of JH production remain to be elucidated.     

Emergency transport by aeromedical blimp.

Recently there has been an explosive growth in the use of helicopters and fixed wing aircraft for the transportation of patients who are ill and injured. Although using such methods of transport may result in faster access to health care centres, their ultimate role for the civilian population is unclear. Unfortunately, there are many problems associated with aeromedical transport, particularly with rotary wing aircraft, which have shown an alarming tendency to crash. The use of lighter than air vehicles (blimps, hot air balloons) might offer most of the advantages of conventional aieromedical transport, with an appreciable improvement in safety.     

Nicotinic-type unitary currents in Helix neurons

1. The platelet aggregation response to several known platelet agonists was evaluated in four Asian elephants. The platelets were highly responsive to stimulation with platelet-activating factor (PAF) and collagen, less responsive to adenosine diphosphate (ADP) and non-responsive to arachidonic acid, serotonin and epinephrine. 2. Arachidonic acid (1 x 10(-4) M), while inducing no aggregation, caused the release of 1248 +/- 1147 pg/ul (mean +/- SD) of thromboxane B2 (TXB2), the stable metabolite of thromboxane A2 from stimulated platelet. The addition of 1 x 10(-4) M ADP to platelets caused suboptimal aggregation and the release of only 25 +/- 10 pg TXB2/microliters. 3. The calcium channel blocker, verapamil, produced a dose-dependent inhibition of PAF-induced but not collagen-induced aggregation. The cyclooxygenase inhibitor, acetylsalicylic acid, produced no inhibition of either collagen- or PAF-induced aggregation.     

Inhibition of RNA Synthesis and the Relationship between Nucleolar and Mitotic Cycles in Zea mays Root Meristems

The relationship between nucleolar and mitotic cycles has beendetermined after treatment of root apices of Zea mays with ethidiumbromide. In the meristematic regions of the stele the two cyclesare not much displaced in relation to each other except fora delay in the onset of the disorganization phase. A few nucleolipersist into metaphase and a few nuclei undergo an amitoticdivision. In the cap initials the drug greatly delays the onsetof disorganization of the nucleolus, which normally occurs beforeprophase in this region. It also delays the completion of reorganizationso that fully organized nucleoli are no longer available duringthe last half of telophase. In the quiescent centre the onsetof disorganization and the end of reorganization of the nucleoliare also delayed in relation to mitosis. There is no evidencefor a delay in the onset of reorganization in any region ofthe meristem. Some cells form multiple micronucleoli and this aberrant behaviouroccurs more often in the cap initials than elsewhere as doesamitotic division.