Effect of extreme conditions of Antarctica on human leukocyte antigen-G in Indian expeditioners.

Background & objectives: Immune activation and inflammation play critical roles in the stressful environmental conditions like high altitude, extreme cold, etc. Human leukocyte antigen-G (HLA-G) is a non classical major histocompatiblity complex class I (MHC class- I) protein, upregulated in the context of transplantation, malignancy and inflammation. We hypothesized serum HLA-G as a possible stress biomarker and studied levels of soluble form of HLA-G (sHLA-G) in Indian Antarctic expeditioners. Methods: sHLA-G ELISA was performed in the serum of summer (n=27) and winter (n=22) Indian Antarctic expeditioners. The summer expeditioners were evaluated at three different time points, i.e. before leaving India, after one month ship borne journey, and after staying one month at Indian research base, Maitri in Antarctica, while winter expeditioners were evaluated at five different time points, i.e. before leaving India, and in the month of March, May, August and November at Antarctica. Results: one month ship borne journey did not cause any significant change in the sHLA-G level as compared to the baseline level of the summer expeditioners. sHLA-G levels were not changed significantly in the months of March, May, August and November as compared to the baseline level of the winter expeditioners. Interpretation & conclusions: Our results indicated that the extreme conditions of Antarctica did not cause any significant change in the sHLA-G level in both summer and winter expeditioners.

Heart Rate Variabilty Changes During First Week of Acclimatization to 3500 M Altitude in Indian Military Personnel.

Acute exposure to hypobaric hypoxia induces the changes in autonomic control of heart rate. Due to emergencies or war like conditions, rapid deployment of Indian military personnel into high altitude frequently occurs. Rapid deployment to high altitude soldiers are at risk of developing high altitude sickness. The present study was conducted to evaluate the acute exposure to high altitude hypobaric hypoxia (3500 m altitude) on the autonomic nervous control of heart rate in Indian military personnel during first week of acclimatization Indices of heart rate variability (viz; R-R interval, total power, low frequency, high frequency, ratio of low to high frequency) and pulse arterial oxygen saturation were measured at sea level and 3500m altitude. Power spectrum of heart rate variability was quantified by low frequency (LF : 0.04-0.15 HZ) and high frequency ( HF : 0.15-0.5 HZ) widths. The ratio of LF to HF was also assessed as an index of the sympathovagal balance. Mean R-R interval decreased significantly on day 2 on induction to altitude which tended to increase on day 5. Total power (TP) decreased high altitude and tended to recover within a week. Both HF and LF power showed decrement at 3500m in comparison to sea level. The ratio of LF to HF (LF/HF) at 3500m was significantly higher at 3500m. SpO2 values decreased significantly (P<0.05) at high altitude on day-2 which increased on day-5. We conclude that autonomic control of the heart rate measured by heart rate variability was altered on acute induction to 3500m which showed a significant decrease in parasympathetic tone and increase in sympathetic tone, then acclimatization seems to be characterized by progressive shift toward a higher parasympathetic tone.

Current concept in the management of cerebral palsy.

The authors have described, in depth, the current concept along with the management of cerebral palsy in the present article.

Effect of hypobaric hypoxia on visual evoked potential at high altitude.

The effect of hypobaric hypoxia on visual evoked potential (VEP) was studied in 27 male volunteers at sea level (SL), during the 1st and 3rd weeks of their stay at high altitude (HA) of 3,500 m and in the 1st week of their return to the sea level (RSL). Exposure to high altitude (HA) led to significant changes in VEP. The N1 wave latency of both right and left eye was significantly increased (P<0.05) during 3rd week of stay at the altitude which persisted even after the return to the sea level. The latency of P1 wave of both right and left eye was higher in 3rd week at high altitude but not significant statistically. But the delay in P1 latency persisted in 1st week of their return to sea level which was significant (p<0.05) statistically as compared to sea level. The latency of N2 wave was significantly decreased (P<0.05) during the 1st week of stay at HA and returned back to basal value in the 3rd week of stay at HA in both right and left eye. However, the changes observed in NPN complex in terms of wave latencies were within the physiological limits. The amplitude of wave N1-P1 of both the right and left eye did not show any change. The changes observed reflect the process of acclimatisation to 3500m high altitude.

Changes in visual evoked potentials on acute induction to high altitude.

BACKGROUND & OBJECTIVES: Induction to high altitude leads to altered central nervous system (CNS) functions induced by hypobaric hypoxia. The sensory systems like visual and auditory systems are reported to be affected by hypoxia. The present study was undertaken to assess the effects of hypobaric hypoxia on visual evoked potentials (VEPs) at 3200 m and 4300 m. METHODS: The VEP of 30 human volunteers were recorded at sea level (SL) and then at high altitude (HA) of 3200 m (HA I) and 4300 m (HA II) in eastern Himalayas and on return to sea level (RSL). The absolute latencies and amplitude of positive and negative waves were recorded. RESULTS: High altitude of 3200 m did not alter the latency of major wave N1, P1 and N2 of the VEPs. At HA II (4300 m), there was a statistically significant increase (P < 0.01) in the latency of NI wave as compared to the SL value and HA I (3200 m) in both left and right eye. There was a slight increase in latenty of P1 wave in both left and right eye at HA II. INTERPRETATION & CONCLUSION: From these results it may be concluded that induction to HA causes increase in latency of N1 wave at 4300 m which is still within physiological limits. This increase in wave latency of N1 wave in both eyes may be due to synaptic delay and/or altered neuronal processing at HA.

Effect of chronic hypobaric hypoxia on components of the human event related potential.

BACKGROUND & OBJECTIVES: Induction to high altitude (HA) leads to deterioration in cognitive functions. The event related potentials (ERPs) like P300 are reported to be affected by hypoxia and bring about impairments in cognitive performance. The aim of the study was to investigate the effect of hypobaric hypoxia on event related potentials at two different altitudes i.e., 3200 m (HA I) and 4300 m (HA II) in ascending order to see how ERPs change with increasing altitude. METHODS: The study was carried out on 20 healthy male volunteers at sea level (SL) and thereafter at high altitude (HA) in Eastern Himalayas and on return to sea level (RSL). The P300 was recorded by using standard auditory odd ball paradigm with compact -4 (Nicolet, USA). RESULTS: The N1, N2 and P2 latencies were not significantly affected at HA I and HA II in comparison with SL indicating no effect of hypobaric hypoxia on sensory conduction. However, at HA II, most of the subjects showed an increase in latency of P3 component reflecting sensory discrimination and delay in evaluation process at 4300 m. At HA I, only 10 out of 20 subjects showed an increase in P3 wave latency and 3 did not show any change in N2-P3 components. INTERPRETATION & CONCLUSION: The results of the present study showed an increase in P300 wave latency at 3200 and 4300 m of high altitude. The observations suggest that hypoxia causes slowing of the signal processing at 4300 m, and magnitudes of the effects are altitude dependent with higher level of decline observed with increasing altitude.

Effect of high altitude on human auditory brainstem responses.

The effect of hypobaric hypoxia on Brain Stem Auditory evoked potentials (BAERs) were studied. BAERs were recorded in 30 volunteers at sea level (SL) and then at high altitude (HA) of 3200 m (HA I) and 4300 m (HA II) in Eastern Himalayas and on return to sea level (RSL). The BAERs were recorded using Nicolet Compact - 4 (USA) in response to monaural auditory stimuli consisting of clicks of 100 ps square pulse at a rate of 15/sec. The BAERs were recorded on day 4 of their stay at 3200 m and 4300 m respectively. Findings indicated an increase in absolute peak latencies of wave V at 3200 m, which was statistically significant. On further ascent to 4300 m there was an increase in absolute peak latencies of wave I and III indicating delay in sensory conduction at the medullo-pontine auditory pathways.

Effect of high altitude (HA) on event related brain potentials.

Event Related brain potentials (ERPs) were recorded in 15 subjects using standard auditory odd ball paradigm, in which subjects were presented a sequence of two distinguishable sound stimuli of that occurred frequently (frequently (frequent stimulus-non target) and the other infrequently (rare stimulus-target). These recordings were made at sea level (SL) and then the subjects were air lifted to 3500 m altitude (HA), where they stayed for 3 weeks. Their ERPs were recorded during the first and third week of stay at HA and on return to sea level (RSL). Data indicated impairment in cognitive function as a result of exposure to HA as depicted by increase in the latency of P3 which was significant during the 1st week of stay at HA compared to sea level. The P3 wave latency during the 3rd week of stay at HA showed an increase compared to SL but was not statistically significant. From the results it may be concluded that high altitude hypoxia induced slow processing of stimulus evaluation, may be responsible for increase in P3 latency. The difference in the latent period of P3 waves during the first and third week of stay at HA may be due to continuous stay at HA which might lead to the time dependent adaptive processes occurring with increasing duration of exposure to HA which may induce learning effects.

Immunodiagnosis in bone and joint tuberculosis.

Fifty patients of bone and joint tuberculosis (age 15-70 years) and 30 healthy controls were studied for levels of immunoglobulin G (IgG), immunoglobulin A (IgA), immunoglobulin M (IgM), T cells and circulating immune complexes (CICs) in different stages of disease. Levels of IgG, IgA, IgM, T cells and CICs were significantly raised in fresh and healed tuberculosis patients, compared to control.

Immunological parameters in leprosy patients with and without arthritis.

Twelve patients of leprosy with arthritis and 161 patients without arthritis were studied for immunological parameters like immunoglobulins (IgG, IgM, IgA), C-reactive proteins and rheumatoid factor. There was increase in the levels of IgG, IgA value in leprosy patients with and without arthritis compared to healthy control. IgM level was decreased in both the groups compared to control, but significant decrease was observed (p < .01) in patients with arthritis. C-reactive protein was significantly positive in leprosy with arthritis group (p < .01) and positive in 12 cases of leprosy without arthritis group compared to negative control group. Rheumatoid factor was present in leprosy with arthritis (16.6%) compared to both the control group and leprosy without arthritis group. This study concluded the presence of arthritis in leprosy patients as a definite entity which showed changes in immunological parameters.

Lactation failure.

Seventy five mothers with lactation failure were studied, whose less than 4-month-old babies were admitted to the hospital. Partial lactational failure (94.7%) was noted more often than complete lactational failure (5.3%). Initiation of breastfeeding was delayed for 2 to 5 days usually for traditional reasons (77.3%) and because the mothers felt that the milk output was inadequate (92%). The various causes of lactation failure were determined and the relationship to various factors was analyzed. The commonest cause of lactation failure was insufficient milk or no milk (80%). The age, parity, education, socio-economic status, religion, family structure and urban vs rural status of mother--all had a bearing on the occurrence of lactation failure. An attempt was made to relactate all these mothers. The outcome was successful in 69.3 cases and failed in only 4% cases. In 26.7% cases, we cannot predict the outcome as the mothers hospital stay was very brief with no follow up.

Osteoarticular tuberculosis in children.

One hundred and four cases of osteoarticular tuberculosis were studied. There were 74 boys (71.2%) and 30 girls (28.8%). The mean age at the onset of symptoms was 7.3 years, ranging from 9 months to 18 years. Seventy four cases (71%) reported 3 months after onset of symptoms. The spine was the commonest site involved (43%) followed by hip (14.9%) and knee joints (10.3%). Evidence of active or inactive pulmonary tuberculosis was found in 16.2%. All cases were treated by three drug regimen of rifampicin, isoniazid and ethambutol; rifampicin was discontinued after 6 months, ethambutol after 12-14 months. In 12 cases (11.5%) isoniazid was continued for 18 months. Along with chemotherapy suitable braces, splints, tractions, exercises and other form of physical therapy produced satisfactory results. Seventy eight patients (75%) showed clinical and radiological improvement with one year of treatment. The follow up period ranged between 4 months to 24 months with an average of 17 months. Children because of capacity to grow, showed progressive deformity in knee in 3 cases (2.8%), hip in 98 cases (8.6%), shortening of limbs in 14 cases (13.4%) and kyphosis in 13 cases (12.5%).

Coitus induced changes in oviductal motility & effect of progesterone.

Motility of different oviductal segments of conscious rabbits was recorded through permanently implanted sensors using the technique of impedance plethysmography. The implants were around the oviductal wall and therefore did not obstruct its lumen. Pre-ovulatory ampullary motility was always less than the isthmic motility. Coitus induced ovulation produced a characteristic oviductal motility pattern consisting of (i) initial relaxation of both isthmus and ampulla (4-12 h) followed by (ii) increased isthmic motility in the face of a continually relaxed ampulla (36-48 h), and finally phase (iii) leading to restitution of both ampullary and isthmic motility to the base-line at 72-96 h. Estimation of ova positions indicated the presence of fertilized eggs in the ampulla and ampullo-isthmic junction at 48 h and the ova could come to the end of the isthmic segment only at 72 h or after. Increased isthmic motility thus served to counter the transportation of ova and their retention in the ampulla. Rabbits in which oviducts were not taken out for ova positioning achieved normal pregnancy. Administration of progesterone (im, 2.5 mg) produced complete relaxation of both isthmus and ampulla, did not produce increased isthmic contractility on coitus, accelerated the ovum transport rate and inhibited pregnancy, again emphasising the ova retentive role of oviductal motility.

Tropical myositis. A clinical immunological and histopathological study.

Thirty cases of tropical myositis, (22 suppurative, 8 non-suppurative) aged 11 to 65 years were seen in a period of one year. There were 22 males and 8 females. There was a total of 78 muscular lesions in 22 suppurative cases and 19 muscular lesions in 8 non-suppurative cases. The most common presentation was localised myalgia (100%), fever (96.7%) generalized myalgia (56.7%), arthralgia (40%), pain in abdomen (33.3%) and breathlessness (30%). Extramuscular complications were present in 50% cases. Twenty four muscle biopsies were taken. Sixteen showed changes of suppurative myositis i.e. non-specific acute inflammatory reaction, muscle necrosis with myocytolysis, vacuolation of cytoplasm and loss of striations. Cell mediated immunity was found to be suppressed in patients of non-suppurative myositis in comparison with the suppurative group. IgG, IgA and IgM were significantly raised in patients in comparison to controls (p less than 0.05). The intact humoral immunity indicates good response to acute phase reaction and increased levels of IgG, IgA and IgM (specially IgG) can be taken as good prognostic parameter.