Deciphering immune microenvironment and cell evasion mechanisms in human gliomas

Gliomas are considered one of the most malignant cancers in the body. Despite current therapies, including surgery, chemotherapy, and radiotherapy, these tumors usually recur with more aggressive and resistant phenotypes. Indeed, the survival following these conventional therapies is very poor, which makes immunotherapy the subject of active research at present. The anti-tumor immune response could also be considered a prognostic factor since each stage of cancer development is regulated by immune cells. However, glioma microenvironment contains malignant cells that secrete numerous chemokines, cytokines and growth factors, promoting the infiltration of immunosuppressive cells into the tumor, which limit the functioning of the immune system against glioma cells. Recently, researchers have been able to reverse the immune resistance of cancer cells and thus activate the anti-tumor immune response through different immunotherapy strategies. Here, we review the general concept of glioma's immune microenvironment and report the impact of its distinct components on the anti-tumor immune response. We also discuss the mechanisms of glioma cell evasion from the immune response and pinpoint some potential therapeutic pathways, which could alleviate such resistance.

Immune Checkpoint Inhibitors in Human Glioma Microenvironment

Gliomas are the most common primary brain tumors in adults. Despite the fact that they are relatively rare, they cause significant morbidity and mortality. High-grade gliomas or glioblastomas are rapidly progressing tumors with a very poor prognosis. The presence of an intrinsic immune system in the central nervous system is now more accepted. During the last decade, there has been no major progress in glioma therapy. The lack of effective treatment for gliomas can be explained by the strategies that cancer cells use to escape the immune system. This being said, immunotherapy, which involves blockade of immune checkpoint inhibitors, has improved patients' survival in different cancer types. This novel cancer therapy appears to be one of the most promising approaches. In the present study, we will start with a review of the general concept of immune response within the brain and glioma microenvironment. Then, we will try to decipher the role of various immune checkpoint inhibitors within the glioma microenvironment. Finally, we will discuss some promising therapeutic pathways, including immune checkpoint blockade and the body's effective anti-glioma immune response.

'Health, Environment and Training': Guidance on conduct of physical exertion in hot and humid climates

Background

Military operations and training in hot environments present a special set of challenges to medical personnel who must support them.

Methods

Various meteorological parameters such as relative humidity (RH), ambient air temperature (Ta) and radiant temperature (Tg), were evaluated at training sites in a desert region. Development of a colour coded Heat Stress Prevention Decision Aid Tool was done using an existing guideline chart.

Results

Temperatures were being recorded routinely by ordinary meteorological instruments mounted within a Stevenson Screen. Onsite measurements with a USB datalogger was found to be relevant in making a decision on suitability of weather for conduct of training. Heat casualties occur when the stresses imposed by some combination of environment, work, and clothing combine to exceed individual tolerance limits. Personnel may encounter high environmental heat loads while working outdoors; during road marches; and while carrying loads or undertaking mechanical maintenance activities. Preventive strategies cannot be expected to eliminate heat stress but should minimize its impact on training while preserving the health of personnel to the extent possible.

Conclusion

It is recommended that onsite measurement of meteorological parameters should be done, and a decision tool should be utilized for arriving at a spot decision by junior leaders.

Dengue in the deserts: Search and Destroy Operations

Dengue, a viral disease transmitted by the Aedes mosquito has the potential to cause outbreaks in urban settings. Planned and coordinated actions including entomological surveillance need to be undertaken at the community level, through synergized efforts by all partners and stakeholders. The experience of conducting such a Task Force based action plan for prevention and control of dengue, in a desert township is highlighted in this study.

Prolonged constriction of sciatic nerve affecting oxidative stressors & antioxidant enzymes in rat

BACKGROUND & OBJECTIVE

This study was carried out to determine the effects of reactive oxygen species in the balance between the pro-oxidant and antioxidant levels in experimental peripheral constriction injury induced by silver wire looping of sciatic nerve of rats.

METHODS

Rats were divided into experimental group 1 (silver wire ligated) and group 2 (control, sham operated). Functional and behavioural activities were assessed by a modified Basso Beattie Bresnahan (BBB) locomotory rating scale. Mechanical pain intensity was measured with Randall and Selitto apparatus. Foot positioning, toe spread, paw withdrawal threshold and paw withdrawal latency were carried out on days 1, 3, 7, 14, 21 and 28 in rats with chronic pain. Oxidative stress markers such as malondialdehyde (MDA) and advanced oxidation protein products (AOPP) were measured along with antioxidants such as glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT) and reduced glutathione (GSH) on day 30 after constriction in sciatic nerve, spinal cord, dorsal root ganglion, dorsal root and ventral root.

RESULTS

Significant (P<0.05) increase in MDA, AOPP, SOD and GPx and decrease in the GSH and catalase activities in sciatic nerve, spinal cord, dorsal root ganglion, dorsal root and ventral root were observed in experimental group rats compared to control group. There was no recovery in foot positioning and toe spread. Reduced paw withdrawal threshold and paw withdrawal latency was observed in ligated rats compared to control rats.

INTERPRETATION & CONCLUSION

Foot positioning, toe spread, paw withdrawal threshold and paw withdrawal latency with no recovery until day 30 confirmed locomotory deficits, hyperalgesia and neuronal impairment. Oxidative stress evidenced by increased MDA, AOPP and decreased GSH and catalase support the generation of reactive oxygen species in constriction model. The present experimental model for chronic pain induced by silver wire spirally coiled around sciatic nerve may be useful for future studies.

ac susceptibility and ESR studies on vapour phase grown Cd(1-x)Mn(x)Te crystals

Single crystals of Cd(1-x)Mn(x)Te for x = 0.1, 0.2, 0.3, 0.4 and 0.5 were grown by a modified vapour phase growth technique. ac magnetic susceptibility studies were carried out in the temperature range 14-300 K. Both the real and the imaginary parts of susceptibility indicated the formation of spin-glass phase at low temperatures. ESR spectra were recorded at room temperature (300 K) at 9.4 GHz for samples of all compositions. The line width (DeltaH) increased with Mn content.

Melatonin in medically ill patients with insomnia: a double-blind, placebo-controlled study

BACKGROUND

It has been suggested that melatonin improves sleep functioning, but this possibility has not been studied in medical populations.

METHOD

33 medically ill persons with initial insomnia were randomly assigned to receive either melatonin (N = 18) or placebo (N = 15) in a flexible-dose regimen. Double-blind assessments of aspects of sleep functioning were obtained daily across the next 8 to 16 days.

RESULTS

The mean stable dose of melatonin was found to be 5.4 mg. Relative to placebo, melatonin significantly hastened sleep onset, improved quality and depth of sleep, and increased sleep duration without producing drowsiness, early-morning "hangover" symptoms, or daytime adverse effects (p < .05). Melatonin also contributed to freshness in the morning and during the day and improved overall daytime functioning. Benefits were most apparent during the first week of treatment.

CONCLUSION

Melatonin may be a useful hypnotic for medically ill patients with initial insomnia, particularly those for whom conventional hypnotic drug therapy may be problematic.

Reduced nociceptive responses in mice with alloxan induced hyperglycemia after garlic (Allium sativum Linn.) treatment

Administration of ethanol (95%) extract (45 mg/kg body wt/day for 28 days) of garlic (A. sativum) to alloxan induced diabetic (ALX-D) mice significantly lowered the serum glucose levels, nociceptive response in tail-flick, hotplate, allodynia, formalin test and relative thickness, weight of hind paw in formalin induced Paw oedema test, over 28 days, thus, showing the reversal trend in hyperglycemia and hyperalgesia compared to ALX-D mice. The reversal of hyperglycemia and hyperalgesia was progressive and more effective as duration of extract administration increased. The results suggest therapeutic potential of ethanol extract of garlic for anti-hyperglycemic and anti-nociceptive effects in diabetes.

Transient elevations of AChE in soleus, plantaris and EDL muscles of palm squirrel (Funambulus palmaram) during prolonged reinnervation

Recovery of acetylcholinesterase (AChE) activity after nerve crush was observed at second week in soleus (slow-extensor) and plantaris (fast-extensor) muscles whereas the same was observed in extensor digitorum longus (fast-flexor) only after third week. In contrast to earlier observations the AChE was found to exhibit specific transient elevations with intermittent reversal to control values in different type of skeletal muscles during later periods of reinnervation.

Redifferentiation and subsequent dedifferentiation of the livers of roosters resulting from acute estrogen challenges

1. Histologic and metabolic changes take place in livers of rooster receiving challenges consisting of acute doses of estrone. 2. During initial Growth and Redifferentiation livers rapidly increase in size by division of hepatocytes within most lobules, changing from cordlike to acinar configurations. 3. No new lobules appear and degeneration of some cells within lobules takes place even as cell divisions predominate. 4. Cells within lobules assume secretory features. 5. Vitellogenins, very low density lipoproteins, calcium and alkaline phosphatase increase greatly in plasma. 6. Within 35-40 days of cessation of estrogen, livers have returned to near normal sizes and plasmas exhibit normal parameters.

Immunologic and morphologic effects of cryosurgery of the monkey (macaque) prostate

A reduction in size of the Macaque prostate following single and multiple in situ freezings was accompanied by histologic alterations, which occurred predominately in the caudal lobe and were characterized by what appeared to be specific periacinar foci of lymphocytic infiltrates. These lymphocytes were observed to infiltrate onto acinar epithelial cells, resulting in their subsequent separation from the basal lamina and epithelial destruction. Other histologic alterations were in consonance with studies of the prostate following cryosurgery by others. Circulating antibodies specific for prostate were present in only one of the seven animals at the time at which these histologic observations were made. These observations suggest the possible development of a cellular immunologic response following cryosurgery of the prostate. The relevancy of these observations to those obtained following cryoprostatectomy in man and other species is considered. Pending confirmation, they may be of potential significance in providing an explanation of reported cases of eradication of human prostatic carcinomas following cryotherapy.

Cholangiocarcinomas induced by feeding 3'-methyl-4-dimethylaminoazobenzene to rats. Histopathology and ultrastructure

Thirty-three male Sprague-Dawley rats were fed a carcinogenic (0.064% 3'-methyl-4-dimethylaminoazobenzene, 3'-Me-DAB) ground meal normal diet. After 12 weeks the ground meal diet was replaced with a normal pellet diet, and the 30 surviving animals were divided into three equal groups. One group was sacrificed at the twelfth week and the other groups 4 and 8 weeks later. Control animals were also run. Based on previous studies which used "tumor-promoting" diets and 3'-Me-DAB, we expected a less than 100% incidence of predominantly hepatocellular carcinomas. However, we found mucin-producing cholangiocarcinomas in all 30 animals and, in addition, a small hepatocellular component in 3 of the animals. By electron microscopy the intestinal mucosal features of microvillous border cells, goblet cells, and endocrine-like cells were found. We suggest that the tumors produced as described here provide a good animal model of mucin-producing cholangiocarcinomas.

B-complex vitamins in cultured and acidified yogurt

Studies were to determine the effect of various factors upon B-vitamin content of cultured yogurt and to compare the B-vitamin contents of cultured and direct acidified yogurt. Incubation of yogurt culture at 42 C for 3 h yielded maximum vitamin synthesis concurrent with optimal flavor and texture qualities. A method was standardized for the manufacture of direct acidified yogurt involving the use of Stabilac acidulant and nonfat dry milk, Carboxymethyl cellulose, gelatin, and Starite. Acidified yogurt showed a slightly higher content of certain B-vitamins than the cultured yogurt due to the contribution made by various food additives. Both cultured and acidified yogurt showed good keeping quality and freedom from microbial contaminants during storage at 5 C for 16 days. However, folic acid and vitamin B12 contents decreased 29 and 60% in cultured yogurt and 48 and 54% in acidified yogurt.