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PubMedDate not supplied

Effects of 10-hydroxycamptothecin, delivered from locally injectable poly(lactide-co-glycolide) microspheres, in a murine human oral squamous cell carcinoma regression model.

This study investigated whether local delivery of 10-hydroxycamptothecin provides effective inductive chemotherapy as assessed by significant tumor reduction. Established tumorigenic human oral squamous cell carcinoma cells were used for these experiments. The experimental groups were comprised of: control (blank (no drug) poly(lactide-co-glycolide) (PLGA) microspheres), intraperitoneal 10-hydroxycamptothecin delivery + blank microspheres, local bolus 10-hydroxycamptothecin + blank microspheres, and PLGA controlled-release microspheres. The 10-hydroxycamptothecin dose administered was 12 mg/kg (bolus-intraperitoneal, local) or controlled-release over 10 days. Regardless of delivery route, 10-hydroxycamptothecin significantly reduces tumor volume. However, PLGA microspheres provide significantly higher intratumor-drug concentrations (approximately 10 and 100 fold higher) relative to local bolus and intraperitoneal routes, respectively. Also, only the PLGA microspheres significantly reduced tumor weights. Camptothecin clinical applications are limited by drug inactivation at physiological pH and the need for sustained infusions. However, due to their acidic, camptothecin-stabilizing microclimate, PLGA microspheres could provide a novel delivery system for camptothecin-based induction chemotherapy.

Animals↗
PubMed1998

[Possibility of adopting hypoxic environment in the cabin for manned space flight].

The favourable and the unfavourable factors of normal baric hypoxia (1.0 atm, oxygen concentration below 21%) and hypobartic hypoxia (cabin pressure below 1.0 atm, 21% O2) in the cabin for manned space flight were discussed. Author considered that proper hypobaric hypoxia in the cabin (0.8-0.9 atm, 21% O2) would be benifit no matter for long or short term space flight. For long term space flight, the microclimate control model in the cabin should be considered again, it controlled in a narrow comfortable zone would unfavourable to human adaptability to changing environment. All these problems proposed in this paper need to be further studied.

Air Conditioning↗
PubMed1975

Arterial and tissue gas tensions in rats during development of pulmonary oxygen poisoning.

Oxygen and carbon dioxide tensions of arterial blood and subcutaneous tissue were studied in rats during 84 h of continuous exposure to oxygen. O2 and CO2 tensions in the subcutaneous tissue were measured by means of an implanted Silastic tonometer. As pulmonary edema developed after 48 h of exposure to oxygen, Pao2 started to decline and PaCO2 rose. Tissue Po2 decreased below the normal level already after 24 h of exposure, probably due to O2-induced vasoconstriction. After 84 h of oxygen exposure, the mean tissue Po2 was 29 mm Hg. In general, a distinctly hypoxic tissue microclimate was not observed. After 48 h of exposure to oxygen, the tissue PCO2 exceeded the control level. An 84-h exposure resulted in a profound retention of CO2, both in peripheral tissues and arterial blood. It is concluded that, in contrast to earlier suggestions, hypercapnia rather than hypoxia is the final factor leading to death in oxygen toxicity.

Animals↗
PubMed2000

[Numerical simulation on maize growth in a regular windbreak system in Huanghuaihai Plain].

The modified production ecological model SUCROS was used to simulate the growth process of summer corn with the protection of windbreaks in Huanghuaihai Plain, and the simulated result was compared with the field monitoring data. The effects of various physiological and ecological factors that affect the growth of the summer corn were analyzed. The modified SUCROS could simulate the growth process successfully. The leaf area index and organ biomass simulated by the model could be fairly consistent with the monitoring data when the effects of insect and disease pests and weeds were considered simultaneously. As compared with the simulated data in the monoculture field, the corn yield in the windbreak system was about 6.8% higher due to the improved microclimate. Based on the simulation of the relationships between sowing density, sowing date and seed production, the density standard for high yield in the region was 6.75-7.50 plants.m-2, even high as 9.00 plants.m-2 in the fields with sufficient soil nutrients and water supply. It is suggested that the optimal sowing period is from May 21 to June 5. Through simulating the influence of "cool summer" on the growth of summer corn in southern Huanghuaihai Plain, it was found that the growth period of corn would extend 3 to 4 days if the average air temperature during the growing period lowered by one degree. The "less radiation" and correspondent "lower temperature" were the direct reasons of yield reduction in "cool summer".

Biomass↗
PubMed2000

[Immunologic reactivity and status of the intestinal viral flora of humans in pressurized chambers].

Immunity status and intestinal viral flora were studied in 5 experiments with long-term exposure of 26 male subjects in pressurized chamber. In two experiments with congenital microclimate and gaseous environment cellular and humoral indices of immunity did not deviate from the physiological norm. None of 14 subjects in these experiments was identified as a virus-carrier. In three experiments with hard environmental conditions (elevated concentrations of ammonia and carbon dioxide) viruses were isolated from 8 out of 12 subjects. Activation of viral flora mainly occurred on a background of impaired immunologic reactivity. In two experiments carriage of virus was asymptomatic; in the third experiment with the rise of ammonia up to 7 mg/m3 two subjects developed clinic signs that could have been engendered by enteric viruses, the Coxsackie B strain specifically.

Adult↗
PubMed1999

[An analysis of nutritional and harmful components of vegetables grown in plastic greenhouses].

OBJECTIVE: To study the changes in nutritional and harmful components of vegetables grown in plastic greenhouses. METHODS: In plastic greenhouses, microclimate and air concentrations of carbon monoxide, carbon dioxide, fluoride and respirable particulate were measured, and chlorophyll, total sugar, crude fiber, nitrite, fluoride, arsenic and some mineral elements in vegetables were determined as compared with those grown in the open-air fields. RESULTS: Greenhouse appeared a lower wind speed and darker illumination. Contents of chlorophyll a an b, total chlorophyll, reduced vitamin C, crude fiber in vegetables grown in greenhouse all were lower than those grown in open-air fields. Contents of potassium, calcium, magnesium, iron, zinc, copper and phosphorous were all lower in the vegetables grown in greenhouse than those grown in open-air fields. The contents of chlorophyll reducing Vitamin C. CONCLUSION: Lower wind speed and inadequate illumination in greenhouse affected photosynthesis and uptake of water in vegetables causing changes in their nutritional components. But, no contamination of burning coal was found in vegetables grown in greenhouse.

Air Pollutants↗
PubMed2002

[Health threats for children in the modern building trade].

Changes in building industry during last 30 years in search of economic technologies and building materials ended in creating airtight and energy-saving constructions with reduced ventilation. As a result, diminish exchange between internal and external air, leads to cumulation of various chemicals and organic substances in our houses. Concentrated oxidation products (CO2, CO, NO2, nicotine smoke), vaporizing substances (formaldehyde, NH3, aromatic hydrocarbons) might irritate mucouses, promote or intense respiratory tract infections, allergic diseases or bronchial asthma. Higher risk of atopic diseases and bronchial asthma also arises from proliferation of fungus, bacteria and mites in modern interiors, which are quite convenient for it. Buildings with microclimate, which is dangerous for human health, are termed "sick buildings". Diseases that develop under their influence are called BRI (building related illnesses). Children are most exposed on them, especially under municipal conditions, because they spend majority of their time at home.

Air Pollution, Indoor↗
PubMed1965

Manned space flight--some scientific results.

The paper presents the data of medical monitoring and physiological research carried out during the flights of V.F. Bykovsky, V.V. Tereshkhova and partially of G. Cooper. The results of measurements of hygienic parameters and microclimate testify to good reliability of life-support systems employed aboard the spacecraft. The analysis of the information of medical monitoring and physiological investigations allows the conclusion to be made that 5-day manned space flight causes no pathological changes. No essential peculiarities related to tolerance of flight factors by woman as compared to man have been revealed either. In conclusion the authors formulate basic tasks confronting physicians in performing physiological and hygienic investigations to promote further development of manned space flight.

Adaptation, Physiological↗
PubMed2002

Heat strain reduction by ice-based and vapor compression liquid cooling systems with a toxic agent protective uniform.

BACKGROUND: The purpose of this study was to compare a vapor compression microclimate cooling system (MCC) and a personal ice cooling system (PIC) for their effectiveness in reducing physiological strain when used with cooling garments worn under the impermeable self-contained toxic environment protective outfit (STEPO). A second comparison was done between the use of total body (TOTAL) and hooded shirt-only (SHIRT) cooling garments with both the MCC and PIC systems. It was hypothesized that the cooling systems would be equally effective, and total body cooling would allow 4 h of physical work in the heat while wearing STEPO. METHODS: Eight subjects (six men, two women) attempted four experiments at 38 degrees C (100 degrees F), 30% rh, 0.9 m x sec(-1) wind, while wearing the STEPO. Subjects attempted 4 h of treadmill walking (rest/exercise cycles of 10/20 min) at a time-weighted metabolic rate of 303 +/- 50 W. RESULTS: Exposure time was not different between MCC and PIC, but exposure time was greater with TOTAL (131 +/- 66 min) than with SHIRT (83 +/- 27 min) for both cooling systems (p < 0.05). Cooling rate was not different between MCC and PIC, but cooling rate while wearing TOTAL (362 +/- 52 W) was greater than with SHIRT (281 +/- 48 W) (p < 0.05). Average heat storage was lower with MCC (39 +/- 20 W x m(-2)) than with PIC (50 +/- 17 W x m(-2)) in both TOTAL and SHIRT (p < 0.05). Also, average heat storage while wearing TOTAL (34 +/- 19 W x m(-2)) was less than with SHIRT (55 +/- 13 W x m(-2)) for both cooling systems (p < 0.05). The Physiological Strain Index (PSI) was lower in MCC-TOTAL (2.4) than MCC-SHIRT (3.7), PIC-SHIRT (3.8), and PIC-TOTAL (3.3) after 45 min of heat exposure (p < 0.05). CONCLUSIONS: Total body circulating liquid cooling was more effective than shirt-only cooling under the impermeable STEPO uniform, providing a greater cooling rate, allowing longer exposure time, and reducing the rate of heat storage. The MCC and PIC systems were equally effective during heat exposure, but neither system could extend exposure for the 4 h targeted time.

Body Temperature↗
PubMed1975

[Comparative study of microbial and mold pollution of the air in locations for poultry-keeping in various technologies].

Experiments were carried out to establish the microbial and mold contamination of the air on premises where birds were raised following varying patterns of tending and feeding. It was found that on premises for layers, raised in cages, the microbial contamination of the air was 2-3 times lower. The results obtained showed that the main source of air contamination in places where birds are kept is the litter (the other alternative being the floor type of raising). Differences were established in the egg laying, on the one hand, and the forage intake per 'market' egg, on the other, comparing the two types of raising. As all other factors of microclimate were within the normal range of zoohygiene standards, the basic factor which was incriminated to affect both productivity and forage intake per egg was the amount of the microbial flora of the air. Studies have shown that the number of birds per unit of area is an important factor determining the microbial contamination of the air and the health condition of birds.

Air Microbiology↗
PubMed2002

[Physical factors and stress].

Physical factors of occupational environment and surroundings (noise, vibration, non-ionizing electromagnetic radiation, microclimate, etc) frequently could be considered stressing hazards, as cause marked functional changes in cardiovascular and nervous systems, in hematologic, immune and cytochemical values. These changes demonstrate adaptation and compensation processes or disadaptation and subsequent asthenic, astheno-vegetative and hypothalamic syndromes.

Adaptation, Physiological↗
PubMed2002

[Comprehensive evaluation of a host of factors influencing thermal load on workers].

The article represents mathematic simulation that enables to determine human heat content for those working in heating environment, using complex of factors causing thermal load, and to assess role of each factor in formation of this load. The authors necessitate evaluation of heating microclimate and specification of requirements to a work mode considering clothes influence on heat accumulation that could be calculated by the equations presented.

Adult↗
PubMedDate not supplied

[Effect of the photoperiod of the site of oviposition of Aedes mariae (Diptera,Culicidae)].

The overwintering biology of Aedes (Ochlerotatus) mariae (one of the sibling species of the mariae complex) was studied in populations from the Tyrrhenian coast of Central Italy (Sperlonga and Formia). Ae. mariae has in this zone several generations per year and its larvae are commonly found from March to October exclusively in rock pools along the coast. Field and laboratory observations show in these populations an embryonic winter diapause induced by short-day photoperiods (9-12 hours). The photoperiod acts primarily on the parental females during their preimaginal life. The expression of diapause is influenced by temperatures and photoperiods experienced by the embryos. Full embryonic diapause is observed when the eggs are incubated at relatively low temperatures (less than 16 degrees C) and at short photoperiods. Short-day photoperiods also induce a remarkable change in the oviposition behavior of Ae. mariae. Laboratory observations show that the adult females readily oviposit on water surfaces when originating from larvae reared at long-day photoperiod while they are very reclutant to oviposit in the same situation when reared at short day photoperiod. Choice experiments involving four alternative oviposition sites (see Plate 1) demonstrate a preference for outside free water in long-day mosquitoes and for inside moist surfaces in short-day mosquitoes. The behavioral difference persists in successive gonotrophic cycles and it is not apparently affected by the photoperiod acting on the adult females. The above evidence together with recovery of overwintering eggs in holes and crevices of rock pools suggest that the shift in oviposition site shown in the laboratory reflects a similar shift occurring in nature. Such photoperiodically induced change in oviposition behavior seems to have an important adaptive significance in providing more constant microclimates to the diapausing eggs and in protecting them from the mechanical action of winter storms.

Aedes↗
PubMed2002

The effect of heat exposure on cortisol and catecholamine excretion rates in workers in glass manufacturing unit.

The aim of the investigation was to study the effect of long term repeated heat exposure on the excretion rates of stress hormones of workers in glass manufacturing unit. Sixteen operators, exposed to heat, were studied during the hot period and compared to a control group of 16 subjects, working in the same manufacturing unit. Both groups had moderate work load. The microclimate components and the Wet Bulb Globe Temperature were used for defining the heat exposure. The excretion rates of cortisol, adrenaline and noradrenaline were followed during the early morning shifts on three hour intervals using RIA and fluoriphotometric methods. Heart rate was followed, too. The psychosocial factors were measured by the "My job" questionnaire. Highly significantly higher cortisol, noradrenaline and adrenaline values were measured in the heat exposed operators compared to the control group, while significant differences of the psychosocial factors between the two groups lacked. Even if the heart rate was in the safe limits, the found alterations in the stress system are considerable and indicate heat stress. The work in conditions of overheat is associated with considerable heat stress and the possible health implications need to be clarified.

Adult↗
PubMed2002

[Ecological functions of green land system in Harbin].

Patch and strip green lands in Harbin with plantation structure of tree + shrub + herb, tree + herb, shrub + herb, tree, shrub, and lawn were selected as studied objects. Through testing PAR, temperature (t), relative humidity (RH), and CO2 concentration in the center and outside of the selected green lands, the ecological functions of the green lands on regulating city microclimate were analyzed. The results showed that except lawn, patch green lands had the function of shading. Green lands with plantation structure of tree + shrub + herb, tree, tree + herb, and shrub had greater effects on lowering temperature, increasing humidity, and adjusting CO2 concentration than that of lawn. Strip green lands also had certain effects on shading, lowering temperature, increasing humidity, and adjusting CO2 concentration. Among different plantation structures of stripe green lands, shrub had the best effect on shading, and tree + shrub had the best effects on lowering temperature, increasing humidity, and adjusting CO2 concentration. The ecological functions of patch green lands were better than those of strip green lands with the same plantation structure, and green lands with multistoried structure had greater ecological effects than those with single layer.

Carbon Dioxide↗
PubMed2003

[Effects of free air CO2 enrichment on rice canopy energy balance].

The change of crop canopy energy balance will affect crop growth and development and its water use efficiency. In this study, the FACE system (setup at at Anzhen, Wuxi, Jiangsu Province in 2001) was used to investigate the effects of FACE on rice canopy energy balance. The rice canopy microclimate observations were carried out from August 26 to October 13, 2001 when the rice crops were at the heading to maturing stage. The results showed that the maximum difference of rice canopy sensible and latent heat fluxes between ambient and FACE occurred at the same time of minimum air humidity, i.e., at about 14:00. From flowering to maturing stage, the maximum difference of rice canopy sensible and latent heat flux between FACE and ambient varied between 12-55 J.m-2.s-1 and -15(-)-65 J.m-2.s-1, respectively. The daytime total canopy sensible and latent heat fluxes of FACE were higher and lower than those of ambient, respectively, throughout flowering to maturing stage. The differences of daytime total canopy sensible and latent heat fluxes between ambient and FACE increased with the increase of net radiation above canopy during the same development stage, but decreased with the progress of the development stage. From flowering to maturing stage, the average difference of daytime total canopy latent heat flux between ambient and FACE was about 6.7%. FACE increased and decreased the ratio of daytime total canopy sensible and latent heat flux to daytime total net radiation above canopy, respectively, the ratio differences between FACE and ambient were 5.5%.

Air↗
PubMed2003

[Species diversity and managed ecosystem stability].

Based on partial experimental data of the studies on managed communities over 40 years, various managed communities in terms of ecological structures, e.g., rubber or tea plantation in one species with one community layer, rubber-tea and rubber-coffee of two species with two community layers, rubber-luofumu-qiannianjian of three species with three community layers, and artificial rain forest with multiple species and layers (hundred species with five layers) were discussed. The differences in systematic functions among three structures of the community were discussed, mainly from the followint spects: Biomass, productivity, and economical productivity; capability of protection and improvement of community environment (microclimate, soil etc.); capability of resistant to natural disaster (chilling and storm). The biomass and productivity in the system were significantly increased, as there were more species and vertical layers in the community. As the community structure became complicated, the microclimatic factors inside the system were marked changed: relative humidity was higher, maximum temperature was lower, minimum temperature was higher, wind slowdown velocity was slowed down, soil erosion reduced, and the resistance to chilling and storm become stronger. It is concluded that the stability of the system could be greatly affected by an artificial ecosystem.

Biomass↗
PubMed1992

[Significance of exposure of workers in the tanning industry and the prevalence of upper respiratory tract diseases].

Respiratory diseases are in prevalence under the other diseases in industry of leather. The exposition to the chemical irritances like bensen and toluene is very important, because a short exposition gives early symptoms. We found in 54% of examined population pathologic ORL cases in a sense of hypertrophic and atrophic forms rhinitis and pharyngitis. Bacterial flora is pathologic in 20% of examined workers and comparing positive bacteriologic form between nose and pharynges we found infections of mucose of nose more frequent than the throat. The occupational atmosphere and its microclime is very important in pathology of upper respiratory diseases. It is etiological factor in morphological changes of the respiratory mucosas. At the end, we can say that the ordinary monitoring which contains monitoring of working place, and biologic monitoring which means ORL, bacteriological, biochemical and toxicologic examinations must be regulated.

Humans↗