Applications of Inertial Navigation Systems in Medical Engineering

Inertial navigation systems are of the most important and practical systems in determining the velocity, position and attitude of the vehicles and different equipment. In these systems, three accelerometers and three gyroscopes are used to measure linear accelerations and angular velocities of vehicles, respectively. By using the output of these sensors and special inertial algorithms in different frames, parameters of vehicle such as position, velocity and attitude can be calculated. These systems are used in medical equipment including, but not limited to MRI devices, intelligent patient beds, surgical robots and angiography equipment. In this paper, inertial navigation systems, inertial sensors such as accelerometers, gyroscopes and inertial navigation algorithm are introduced. Afterwards, different applicable samples of inertial navigation system in medical equipment are described. According to the study carried out in this paper, it is presented and proved that applying inertial navigation in medical equipment is granted with precise and fast positioning as well as attitude determination. Moreover, as this technique of utilizing inertial navigation is applied to medical devices, a high efficiency system in terms of specifying the position and attitude will be achieved.

Pulmonary tuberculosis in migratory nomadic populations: the missing link in Iran's National Tuberculosis Programme

OBJECTIVE

To detect pulmonary tuberculosis (PTB) in migratory nomadic populations in Fars Province, southern Iran.

DESIGN

Cross-sectional study.

RESULTS

In this study, 5506 (82.8%) of a total nomad population of 6650 from 1337 tents were screened for PTB. The mean age was 27.4 ± 18.2 years (range 1-109). Based on clinical symptoms, 141/5506 (2.6%) were identified as TB suspects. One male and three female adult new smear-positive PTB cases were detected, giving an incidence rate of 0.7/1000 population compared to 0.08/1000 in the general population of the region, and 28.4/1000 TB suspects. The median time to onset of symptoms in detected cases was 82.5 days. Tribal stigma against female TB patients was one of the main barriers to appropriate health-seeking behaviour.

CONCLUSIONS

The incidence of smear-positive PTB among migratory nomads is approximately nine-fold higher than in the general population. Active screening of TB in migratory nomads should be integrated into Iran's national TB control programme. The issue of destigmatisation, particularly among female TB patients, should also be addressed.

Association between epidermal interleukin-10 secretion and the ability of cotransplanted skin from neonatal donors to prolong adult allograft survival

Cotransplantation of skin from neonatal donors prolongs the survival of adult skin allografts on rabbit anti-mouse lymphocyte serum-treated and donor bone marrow cell-treated mice relative to controls (the cotransplant effect). In B6AF1 (H2a/b) recipients, cotransplants of skin from C3HeB/FeJ (C3H; H2k) neonates up to 6-7 days old prolonged the survival of adult C3H skin grafts. Skin from 9- to 10-day-old neonates was inactive. The magnitude of the cotransplant effect declined with increasing cotransplant age. Although few class II+ cells are present in skin from < 24-hr-old mice, the numbers of these cells increase rapidly after birth. On days 3-4, when the cotransplant effect is strong, their numbers in neonatal skin are greater than in adult skin. Development of class II expression continues when neonatal skin is grafted, but with an apparent 2-day lag. Because class II+ cell numbers decline in grafted adult skin, we speculate that this apparent developmental lag may be due to Langerhans cells migrating from the graft as they mature. Epidermal cells from litters of neonates were cultured overnight and supernatants were tested for interleukin (IL)-10. All 11 samples from 0- to 4-day-old neonates and 4 of 9 samples from 4- to 7-day-old neonates were positive. IL-10 was found in 1 of 9 samples from donors 8-16 days old and 1 of 7 samples from individual adult mice. Thus, there is a temporal association between the ability of neonatal skin to produce a cotransplant effect and its ability to secrete IL-10.

Allograft and xenograft unresponsiveness induced by transplantation of neonatal skin

Class I MHC-disparate skin allografts from neonatal donors survive longer than adult grafts in mice treated with antilymphocyte serum (ALS; days -1, +2) or ALS plus donor bone marrow cells (BMC; day +7 relative to grafting on day 0) or ALS, BMC, and a 2-week course of post-transplant CsA. We have now investigated whether this phenomenon extends to more strongly histoincompatible allografts (H2-KI and H2-KID mismatched) made to recipients treated with ALS, ALS plus BMC, or ALS, BMC, and CsA. Survival of neonatal grafts was longer than that of adult grafts in all experimental groups (P < 0.05). In ALS/BMC/CsA-treated mice, for example, median survival of neonatal C3H grafts was 46 days, with adult grafts surviving 22 days on C57BL/6 recipients (full MHC disparity). Survival of neonatal hamster skin grafted to B6AF1 mice was not augmented beyond that for adult skin using a similar immunosuppressive protocol. But if alternate day ALS and CsA injections were begun on day -5, and ALS and CsA continued as in the allograft models, a significant xenogeneic neonatal survival advantage was demonstrated. (Donor BMC had no graft-prolonging effect in the xenograft model.) Donor BMC significantly prolonged full MHC-mismatched grafts from newborn, but not adult donors in ALS-treated recipients. Also, addition of CsA to ALS/BMC treatment prolonged the survival of neonatal, but not adult grafts mismatched at KI or KID. These results indicate that the survival advantage of neonatal grafts in immunosuppressed recipients extends to strong allogeneic incompatibilities and even to a xenograft model.

Induction of allograft tolerance with neonatal skin

B6AF1 recipients treated with various combinations of ALS, CsA, and BMC were grafted with C3H skin from adult or neonatal donors. A survival advantage of neonatal skin compared with adult skin was clearly demonstrated in groups treated with ALS and CsA (median survival time [MST] = 89 days, neonatal skin; 50 days, adult skin), ALS and BMC, (MST = 92 days, neonatal; 64 days, adult skin), or with ALS only (MST = 55 days and 35 days, respectively). In these groups only neonatal grafts were observed to survive greater than 100 days. Also, once it was underway, rejection of the neonatal skin proceeded more slowly than that of adult skin. ALS/BMC/CsA treatment of adult skin recipients improved graft survival modestly (MST = 77 days, 20% of grafts surviving greater than 100 days). But neonatal graft survival was prolonged remarkably by the ALS/BMC/CsA treatment, with 95% of grafts surviving greater than 100 days and 84% surviving greater than 240 days. After bearing neonatal grafts for greater than 150 days, these mice were challenged with C3H adult skin grafts. The second grafts were uniformly accepted for greater than 135 additional days, but third-party grafts were rejected promptly. This specific tolerance could not be abrogated by injection of normal B6AF1 spleen cells, and rejection of the grafts by adoptively transferred sensitized cells was delayed (MST = 35 days). That the tolerance developed in response to grafting neonatal skin to ALS/BMC/CsA-treated recipients extends to adult tissue suggests that understanding of the immunoregulatory signal provided by the neonatal tissue might lead to a tolerogenic protocol for use with adult allografts.