[Regulation effects of irrigation methods and nitrogen application on soil water, nitrate, and wheat growth and development]

Field experiments were conducted to examine the effects of flooding irrigation (FI), micro-sprinkler irrigation (SI), drip irrigation (DI), combined with nitrogen application (N₁:157.5 kg·hm^-2 as basal, 67.5 kg·hm^-2 top dressed at jointing stage; N₂:157.5 kg·hm^-2 as ba-sal, 45 kg·hm^-2 and 22.5 kg·hm^-2 top dressed at jointing stage and filling stage, respectively) on soil moisture, nitrate (NO₃^--N) content, and wheat growth and development, under maize straw returning to field. Results showed that irrigation methods and nitrogen application modes affected soil water content and soil water storage (SWS). Irrigation methods had limited effect on soil water content in the 0-60 cm soil depth at the wintering and re-greening stages, 0-160 cm soil depth at the booting and filling stages, 100-160 cm soil depth at the mature stage, but had substantial effect on water content in the 80-160 cm soil depth at the wintering and re-greening stages, 0-80 cm soil depth at the mature stage. The effects of irrigation methods on water content and SWS were in the order of FI>DI>SI. Under SI and DI, water content, SWS of soil layers, and their changes increased with increasing irrigation rate. Nitrogen application had obvious effect on NO₃^--N content in the 0-20 cm soil depth. In the SI, variation of NO₃^--N content among different growth stages was evident. In the DI, changes of NO₃^--N content were non-evident during wintering and booting stages, and were evident after booting stage, with opposite change treand in the FI. In general, NO₃^--N content was influenced by irrigation rate at early and middle stages of wheat growth, but was mainly affected by N application at late stage. In the SI and DI, NO₃^--N content changed larger by irrigation rate before winter. Total stem number and tillers per plant during overwintering period, panicle number rate, panicle number, yield, WUE and nitrogen use efficiency (NUE) were in the order of SI>DI>FI. In the SI and DI, total stem number and panicle number were higher in the N₁ than that in the N₂, but grain number per panicle, 1000-grain mass, yield, WUE and NUE were lower. Sowing wheat after maize straw returning to the field, replacing FI with micro-sprinkler irrigation four times during the wheat growth period, applying sufficient basal fertilizer and then topdressing at jointing and filling stages, are the high-efficiency and water-saving cultivation strategies of wheat in wheat-maize double cropping area in southern Shanxi.

Decrease of FGF receptor (FGFR) and interstitial fibrosis in the kidney of streptozotocin-induced diabetic rats

Fibrosis is the final disorder of end-stage renal disease. Activation of fibroblast growth factor (FGF) 23-klotho axis could suppress renal fibrosis in mice. Also, a marked decrease of klotho expression was observed in the kidney of streptozotocin-induced diabetic rats (STZ rats). However, relation of FGF in renal fibrosis remained unclear. This study was aimed to screen the effect of hyperglycemia on FGF receptor (FGFR) and fibrosis in kidney of rats with diabetic nephropathy and investigate this potential mechanism in cultured Madin-Darby Canine Kidney (MDCK) epithelial cells. STZ rats were used to treat with insulin or phloridzin at the dose sufficient to correct hyperglycemia for understanding the changes of renal dysfunction. The cultured MDCK cells were also used to treat with high glucose, hydrogen peroxide, or tiron in addition to transfection of siRNA to silence the klotho. Both insulin and phloridzin reversed fibrosis and FGFR expressions in kidney of STZ rats. It was confirmed in high glucose-exposed MDCK cells. However, klotho failed to modify the level of FGFR in MDCK cells. Meanwhile, FGFR was restored by tiron in MDCK cells and in diabetic rats without changing blood glucose. In conclusion, interstitial fibrosis and decreased FGFR expression are observed in the kidney of diabetic rats. This change is reversed by tiron without the correction of blood glucose. Also, klotho has no effect on expression of FGFR. Thus, decrease of oxidative stress is useful for the recovery of FGFR expression and improvement of renal fibrosis in type-1 like diabetic rats.

The distribution of species and susceptibility of amphotericin B and fluconazole of yeast pathogens isolated from sterile sites in Taiwan

To study the demographic changes of yeasts causing invasive infections in Taiwan, especially with respect to species distribution and antifungal susceptibility, we analyzed isolates obtained from four sterile sites of patients in 19 hospitals in 2002 (155 strains) and again from the same hospitals in 2006 (208 strains). Blood was the most common source of the yeasts, accounting for 73.8% of the total isolates, followed by ascites (21.5%), cerebrospinal fluid (3%), and synovia (1.7%). Candida albicans was the most frequently recovered species (50.1% of the total), followed by Candida tropicalis (20.7%), Candida glabrata (11.6%), Candida parapsilosis (8.5%), Cryptococcus neoformans (3.9%), Candida krusei (0.8%), and nine other species (4.3%). There were one (0.3%) and seven (1.9%) isolates with minimum inhibitory concentrations (MICs) of amphotericin B > or =2 mg/l after 24 h and 48 h incubation, respectively. In addition, there were 15 (4.3%) and 31 (8.6%) isolates with MICs of fluconazole > or =64 mg/l under the same conditions. The MIC(90) value of amphotericin B was 1 mg/l. The MIC(90) values of fluconazole were 4 mg/l after 24 h incubation and 32 mg/l after 48 h incubation. Interestingly, MICs for fluconazole > or =64 mg/l after 24 h were significantly higher for isolates obtained in 2006 than those in 2002 after 24 h (7.1% vs. 0.7%, p =0.009) and 48 h (13.5% vs. 2%, p =0.0003) incubations. The demographic difference between these two surveys is mainly due to one species, C. tropicalis.

Decrease of bone morphogenetic protein-7 (BMP-7) and its type II receptor (BMP-RII) in kidney of type 1-like diabetic rats

Bone morphogenetic protein-7 (BMP-7) expression is known to be protective for renal damage during diabetic nephropathy and disappears early during the progression of diabetic nephropathy. However, changes in expression of BMP-7 and BMP-7 type II receptor (BMP-RII) during kidney nephropathy response to high glucose-induced oxidative stress remain unclear. In this study, we used streptozotocin-induced diabetic rats with diabetic nephropathy and treated them with insulin, phloridzin, or antioxidant tiron. The insulin, phloridzin, or tiron treatment improved the renal function and decreased fibronectin expression in the streptozotocin-induced diabetic rats. Both insulin and phloridzin could reverse the attenuation effects of hyperglycemia on BMP-7 and BMP-RII expressions in the kidneys of streptozotocin-induced diabetic rats through the correction of hyperglycemia. However, the decrease of BMP-7 and BMP-RII expressions in kidney of streptozotocin-induced diabetic rats could be reversed by tiron through decreasing the high glucose-induced oxidative stress but not through changing the levels of glucose. We further confirmed the effect on reversing the BMP-7 and BMP-RII expressions through decreasing oxidative stress by tiron treatment in high glucose exposed mesangial cells. Thus, we suggest that a decrease in oxidative stress is responsible for the improvement of renal function and recovery of renal BMP-7 and BMP-RII expression in streptozotocin-induced diabetic rats.

Whole-body F-18 FDG PET for hepatocellular carcinoma patients after interventional treatment

For hepatocellular carcinoma (HCC) patients after primary treatment, conventional anatomical imagings may not be reliable in detecting residual, recurrent or metastatic lesions. The aim of this retrospective study was to evaluate the usability of FDG PET in the follow-up of HCC patients after prior interventional treatments. The database consisted of 10 male and 2 female (age range, 46-82 years; mean age, 63.4 +/- 11.7 years) who had received primary HCC treatments and underwent FDG PET scans at the National Taiwan University Hospital. The accuracy of FDG PET detection was determined by the histopathological results or other clinical evidences afterwards. Of the 22 lesions, FDG PET studies were able to detect 8 (8/10, 80%) intrahepatic lesions and 8 (8/12, 66.7%) extrahepatic lesions. The lesion based detection rate of FDG PET is 72.7% (16/22). FDG PET was able to detect at least 1 lesion in 11 patients. The 6 false negative lesions in 6 patients include 2 intrahepatic lesions, 1 brain lesion, 1 sphenoid sinus lesion and 2 multiple subcentimeter pulmonary lesions. FDG PET scan is able to provide valuable auxiliary information for the follow up of HCC patients clinically suspicious of recurrence if their conventional image findings are not unambiguous.

Cryptococcus laurentii fungemia in a premature neonate

Cryptococcus spp. other than Cryptococcus neoformans are generally considered nonpathogenic to humans. There are only 15 case reports of disease in humans caused by Cryptococcus laurentii infection. Underlying diseases and predisposing risk factors seem to play an important role in these cases. Our patient is the first case of an extremely low birth weight infant with C. laurentii fungemia reported in the English literature. In our case, the MIC of amphotericin B for C. laurentii was 0.25 to 1 microg/ml and the patient had a good outcome following the administration of amphotericin B at 10 mg/kg combined with central venous catheter removal. There will undoubtedly be an increasing occurrence of unusual fungal infections accompanying further advances in medicine. A high degree of suspicion and improvements in the techniques for culture and identification will contribute to the earlier diagnosis and treatment of unusual fungal infections.

Mastoiditis: a disease often overlooked by pediatricians

Although mastoiditis can be a life threatening disease, clinicians often overlook it because it is uncommon. We reviewed the presentation and management of all children younger than 15 years of age with the discharge diagnosis of mastoiditis in our hospital from January 1994 through December 1999. Nineteen patients that fulfilled the case definition were included. The most common clinical presentation in this series was fever. More specific findings, such as otorrhea, postauricular pain, swelling, and redness of mastoid could be found in less than half of these patients. Only two patients had characteristic physical findings, and mastoiditis was diagnosed in only three patients upon admission. Plain radiographic evidence of mastoiditis was usually not apparent early in the course. In this series, the majority of patients were diagnosed by computed tomography (CT) scans. The present study demonstrates that mastoiditis most commonly presents without a clearly diagnostic set of physical examination and laboratory findings. Mastoiditis should be considered in patients with otitis media or with fever of unknown origin (FUO). The empirical antibiotic treatment should cover organisms commonly found in acute otitis media (AOM), including Haemophilus influenzae, Streptococcus pneumoniae, and Moraxella catarrhalis.

Effects of indoor environmental factors on risk for atopic eczema in a subtropical area

The objective of this study was to examine the relationship between indoor environmental factors and atopic eczema in a subtropical area. A case-control study was performed using participants from a survey that included 144 school children with atopic eczema and 144 age- and gender-matched controls. The study was confined to 4,164 primary school children aged 6-12 yr attending 8 primary schools in Kaohsiung rural municipalities who participated in the study. Cases of atopic eczema were ascertained by asking whether a physician had ever diagnosed this condition in the child. Information regarding the home environment was obtained using a structured written questionnaire, completed by the parents of the children. Of the many indoor environmental factors included in this study, such as dampness and smoking, none was found to be associated with atopic eczema.

Calcium and magnesium in drinking water and the risk of death from breast cancer

The relationship between mortality from breast cancer and the levels of calcium and magnesium in drinking water was examined using an ecological design. The study area consisted of 2.52 municipalities in Taiwan. Data on the levels of calcium and magnesium in drinking water were collected from the Taiwan Water Supply Corporation (TWSC). The age-standardized mortality rate (ASR) for breast cancer ( 1982-1991) was compared among municipalities with different levels of magnesium and calcium in drinking water. Weighted multivariate regression analysis was used, and after adjusting for fertility rates and urbanization, there was a significant inverse relationship between the levels of calcium and magnesium in drinking water and risk of death from breast cancer.

Calcium and magnesium in drinking water and risk of death from prostate cancer

The possible association between the increased risk of prostate cancer and the levels of calcium and magnesium in drinking water from municipal supplies was investigated in a matched cancer case-control study in Taiwan. All eligible prostate-cancer deaths (682 cases) of Taiwan residents from 1987 through 1993 were compared with deaths from other causes (682 controls). The levels of calcium and magnesium in the drinking water of these residents were also determined. Data on calcium and magnesium levels in drinking water throughout Taiwan were obtained from the Taiwan Water Supply Corporation (TWSC). The control group consisted of people who died from other causes, and the controls were pair-matched to the cases by year of birth and death. The adjusted odds ratios for prostate cancer death for those with higher magnesium levels in their drinking water, as compared to the lowest tertile, were 0.73 (95% CI = 0.51-1.03) and 0.64 (95% CI = 0.43-0.96), respectively. The adjusted odd ratios for the relationship between calcium levels in drinking water and prostate cancer were not statistically significant. The results of the present study show that there may be a significant protective effect of magnesium intake from drinking water and other dietary sources against the risk of prostate cancer development.

Fluoride in drinking water and cancer mortality in Taiwan

The possibility that cancer risk is associated with naturally fluoridated water in Taiwan is examined. The 1982-1991 age-adjusted mortality rates for cancer for 10 municipalities whose water supplies contained the highest naturally occurring fluoride concentrations in Taiwan were compared to those rates for 10 matched municipalities with unfluoridated water. The two groups had similar urbanization levels and sociodemographic characteristics. Our study does not support the suggestion that fluoridation of water supplies is associated with an increase in cancer mortality in Taiwan.

Esophageal cancer mortality and total hardness levels in Taiwan's drinking water

The possible association between the risk of esophageal cancer and hardness levels in drinking water from municipal supplies was investigated in a matched case-control study in Taiwan. All eligible esophageal cancer deaths (2084 cases) of Taiwan residents from 1987 through 1996 were compared with deaths from other causes (2084 controls), and the hardness levels of the drinking water used by these residents were determined. Data on water hardness throughout Taiwan have been collected from the Taiwan Water Supply Corporation (TWSC). The control group consisted of people who died from other causes and the controls were pair-matched to the cases by sex, year of birth, and year of death. The results show that there is a 42% excess risk of mortality from esophageal cancer in relation to the use of soft water (adjusted odds ratio and 95% confidence intervals was 1.42 (1.22-1.66). This is an important finding for the Taiwan water industry and human health.

Magnesium in drinking water and the risk of death from diabetes mellitus

This report examines whether magnesium in drinking water is protective against the probability of dying from diabetes mellitus. All eligible deaths from diabetes (6781 cases) of Taiwan residents from 1990 through 1994 were compared with deaths from other causes (6781 controls), and the levels of magnesium in the drinking water of these residents was determined. Data on magnesium levels in drinking water throughout Taiwan were obtained from the Taiwan Water Supply Corporation (TWSC). Controls were pair matched to the cases by sex, year of birth, and year of death. The results of the present study show that there seems to be a significant protective effect of magnesium intake from drinking water on the risk of dying from diabetes mellitus. This is an important finding for the Taiwan water industry and human health.

Female lung cancer and petrochemical air pollution in Taiwan

To investigate the relationship between petrochemical air pollution and female lung cancer, we conducted a matched case-control study among women who had died in Taiwan from 1990 through 1994. Data about all eligible female lung cancer deaths were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. The control group included women who died from nonneoplasms and diseases that were not associated with respiratory problems. We pair-matched the controls to the cases by sex, year of birth, and year of death. Each matched control was selected randomly from the set of possible controls for each case. We used the proportion of a municipality's total population employed in the petrochemical manufacturing industry as an indicator of a resident's exposure to air emissions from the petrochemical manufacturing industry. The subjects were divided into tertiles according to the above indicator. Women who lived in the 2 groups of municipalities characterized by higher levels of petrochemical pollution had a statistically significant higher risk of developing lung cancer than the group that lived in municipalities with the lowest petrochemical air pollution levels (after controlling for possible confounders). The linear trend was also statistically significant (p < .05). The results of this study shed important light on the relationship between the Taiwan petrochemical industry and the resulting risk to human health.

Pancreatic cancer mortality and total hardness levels in Taiwan's drinking water

The possible association between the risk of pancreatic cancer mortality and hardness levels in drinking water from municipal supplies was investigated in a matched case-control study in Taiwan. All eligible pancreatic cancer deaths (883 cases) of Taiwan residents from 1990 through 1994 were compared with deaths from other causes (883 controls), and the hardness levels of the drinking water used by these residents were determined. Data on water hardness throughout Taiwan was collected from Taiwan Water Supply Corporation (TWSC). The control group consisted of people who died from other causes and were pair matched to the cancer cases by sex, year of birth, and year of death. The results show that there is a 39 % excess risk of mortality from pancreatic cancer in relation to the use of soft water. Trend analyses showed an increasing odds ratio for pancreatic cancer with decreasing levels of hardness in drinking water. This is an important finding for the Taiwan water industry and human health.

Effects of indoor environmental factors on risk for acute otitis media in a subtropical area

The objective of this study was to examine the relationship between indoor environmental factors and acute otitis media in a subtropical area. A case-control study was performed using participants from a prevalence survey that included 219 school children with acute otitis media and 219 age- and gender-matched controls. The study was confined to 4164 primary school children aged 6-12 yr attending 8 primary schools in Kaohsiung rural municipalities who participated in a prevalence study of the health effects of an indoor environment. An acute otitis media case was defined as a child with acute symptoms (presenting with earache, fever, irritability, and/or discharge from the ear) diagnosed by a physician in the previous year. Controls selected from the same school did not have chronic or acute respiratory illness or an ear-related illness during the same period. Information regarding the home environment was obtained using a structured written questionnaire, completed by the parents of the children. Of the many indoor environmental factors included in this study, only living in a home with indications of dampness (mold, flooding, home dampness) showed an association with acute otitis media. It was concluded that dampness in the home is a new public health issue in subtropical areas.

The incidence of school-related injuries among adolescents in Kaohsiung, Taiwan

OBJECTIVES

To determine the incidence of nonfatal school-related injuries in adolescent schoolchildren.

DESIGN

Nurses completed a Student Accident Report Form (SARF) on all injuries in schools meeting standardized criteria from September 1995 to June 1996.

SETTING

Six junior high schools in Kaohsiung city, Taiwan.

SUBJECTS

13,335 adolescents aged 13-15 in six schools.

RESULTS

A total of 3,640 injuries were reported among the city's 13,335 students, for an overall injury rate of 27.3 injuries/100 student years. Injury rates were higher for boys than for girls at all grade levels. The seventh-grade students had the highest incidence rate. Injuries not involving other students accounted for nearly 64% of all injuries. Injuries occurring on the playground/gymnasium and classroom were the two most common types and were more than twice as frequent as injuries occurring in the hall or stairs. Contusions, abrasions, and swelling were the most frequently reported types of injuries. The body sites most frequently injured were the extremities. When exposure time is taken into account, injury rates were higher in the unsupervised areas of the schools.

CONCLUSIONS

School-related injury incidence among adolescents attending junior high school is higher than has been previously reported and should be recognized as a significant public health problem in Taiwan.

Benign fibrous histiocytoma of the choroid

Benign fibrous histiocytoma (BFH) is a common soft tissue tumour. However, its occurrence in the orbit was not well recognised in the past. It is only in recent years that this condition has become more frequently diagnosed. Now, it is believed to be the commonest mesenchymal tumour of the orbit in adults. Its occurrence in the uveal tract is, however, exceedingly rare. Only one case of presumed fibrous histiocytoma of the choroid has been reported in the literature. We report herein a case of BFH of the choroid in the left eye of a Chinese woman. The patient presented with a huge but asymptomatic raised choroidal mass. Results of choroidal biopsy showed no sign of malignancy but definitive diagnosis could not be made. Enucleation was finally performed. The diagnosis was made on detailed evaluation of the results of the immunohistochemical staining and the ultrastructural findings. The patient remained well at the latest follow-up, which was 33 months after enucleation. Although BFH of the choroid is vary rare, its benign nature and the availability of choroidal biopsy for tissue diagnosis make it important to include this as one of the differential diagnoses for amelanotic choroidal mass.

Hypothalamic neurons preferentially respond to female nest coo stimulation: demonstration of direct acoustic stimulation of luteinizing hormone release

Avian vocalizations are generally understood to play a pivotal role in reproductive functions. The role of the hypothalamus in gonadotropin release in higher vertebrates including birds is well established. To date, however, a direct linkage between the neuronal processing of vocal input and the contingent luteinizing hormone (LH) response has not been demonstrated. In this study, using female ring doves, we recorded neuronal activity from hypothalamic nuclei that, as we have shown previously, receive acoustic inputs from the auditory thalamic relay. Concurrently with recording single-unit responses to stimulation with species-specific coo vocalizations, we sampled LH levels in blood from the pituitary veins. LH concentration in the plasma was significantly elevated in birds hearing species-typical coos but not in birds exposed to experimentally altered coos or white noise or in birds that received no vocal stimulation. We found two types of neurons in the preoptic and anterior hypothalamus that selectively responded to the female nest coo: excitatory units and inhibitory units. Among the excitatory neurons are units characterized by two bursts separated by a period of slow spiking or complete silence, in a pattern approximately corresponding temporally to the two-note coo. We designate them as female-nest-coo-specific units. Most neurons in the posterior hypothalamus were nonselective in their response. Female nest coo and male nest coo stimulation evoked an equal magnitude of discharge changes from responsive units in the preoptic-anterior hypothalamic area. We found, however, that the LH increment was three times greater for birds hearing female nest coos than for birds hearing male nest coos. These observations suggest that feature-detecting neurons such as the female-nest-coo-specific units are involved in gonadotropin-releasing hormone output. The present findings are consistent with the well established behavioral evidence that female nest coos mediate ovarian growth.

Chlorination of drinking water and cancer mortality in Taiwan

Chlorination has been the major strategy for disinfection of drinking water in Taiwan. An ecologic epidemiological study design was used to examine whether chlorination of drinking water was associated with cancer risks. A "chlorinating municipality" (CHM) was defined as one in which more than 90% of the municipality population was served by the chlorinated water while an "nonchlorinating municipality" (NCHM) was one in which less than 5% of the municipality population was served by chlorinated water. Age-adjusted mortality rates for cancer during 1982-1991 among the 14 CHMs were compared to rates among the 14 matched NCHMs with similar urbanization level and sociodemographic characteristics. The results of this study suggest a positive association between consumption of chlorinating drinking water and cancer of the rectum, lung, bladder, and kidney. Although these findings must be interpreted with caution because of limitations in the ecological study design, their public health significance should not be disregarded because chlorination of water is so widely practiced in Taiwan.

Calcium, magnesium, and nitrate in drinking water and gastric cancer mortality

The possible association between the risk of gastric cancer and the levels of calcium, magnesium, and nitrate in drinking water from municipal supplies was investigated in a matched case-control study in Taiwan. Records of gastric cancer deaths among eligible residents in Taiwan from 1987 through 1991 were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. Controls were deaths from other causes and were pair-matched to the cases by sex, year-of-birth, and year-of-death. Each matched control was selected randomly from the set of possible controls for each case. Data on calcium, magnesium, and nitrate levels in drinking water throughout Taiwan were obtained from the Taiwan Water Supply Corporation. The municipality of residence of the cases and controls was assumed to be the source of the subject's calcium, magnesium, and nitrate exposure via drinking water. The subjects were divided into tertiles according to the levels of calcium, magnesium, and nitrate in their drinking water. The results of the present study show that there is a significant positive association between drinking water nitrate exposure and gastric cancer mortality. The present study also suggests that there was a significant protective effect of calcium intake from drinking water on the risk of gastric cancer. Magnesium also exerts a protective effect against gastric cancer, but only for the group with the highest levels.

Gastric cancer mortality and drinking water qualities in Taiwan

The possible association between the risk of gastric cancer and nitrate and hardness in drinking water from municipal supplies was investigated in a matched case-control study in Taiwan. Data on gastric cancer deaths among eligible residents in Taiwan from 1987 through 1991 (6,766 cases) were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. Controls were deaths from other causes (6,766 controls) and were matched individually to the cases by sex, year of birth, and year of death. Data on nitrate-nitrogen (NO3-N) and hardness levels in drinking water throughout Taiwan were collected from the Taiwan Water Supply Corporation (TWSC). The municipality of residence for cases and controls was assumed to be the source of the subject's nitrate and hardness exposure via drinking water. There was no difference in gastric cancer rates between the groups with different levels of nitrate. The odds ratios (95% confidence interval) for death from gastric cancer was 0.95 (0.87-1.03) for the group with water nitrate levels between 0.23 and 0.44 mg/L, and 1.02 (0.93-1.11) for the group with nitrate levels greater than 0.45 mg/L. However, the results show a significant negative relationship between drinking water hardness and gastric cancer mortality. Odds ratios were 1.16 (1.07-1.26) and 1.65 (1.52-1.79), respectively, for exposure to moderately hard water and soft water compared with the use of hard water. This is an important finding for the Taiwan water industry and human health risk.

Effects of indoor environmental factors on respiratory health of children in a subtropical climate

This study was conducted to determine whether indoor environmental factors affected respiratory symptoms in 4164 primary school children in Kaohsiung rural areas of Taiwan. Information on respiratory health symptoms and characteristics of the housing was obtained using a written questionnaire, completed by the parents of children. Multiple logistic regression analysis examined the relationship between respiratory health symptoms (cough, wheezing, bronchitis, asthma, and allergic rhinitis) and housing factors. Home dampness was significantly associated with all respiratory health symptoms. Incense burning and mosquito repellant burning showed effects on the reporting of coughing symptoms. No apparent associations were found with the other indoor factors included in this study or respiratory health symptoms. We conclude that dampness in the home has a pronounced effects on respiratory health symptoms and is a new public health issue in subtropical areas.

Calcium and magnesium in drinking water and risk of death from colon cancer

The possible association between the risk of colon cancer and the levels of calcium and magnesium in drinking water from municipal supplies was investigated in a matched case-control study in Taiwan. All eligible colon cancer deaths (1714 cases) of Taiwan residents from 1989 through 1993 were compared with deaths from other causes (1714 controls), and the levels of calcium and magnesium in drinking water of these residents were determined. Data on calcium and magnesium levels in drinking water throughout Taiwan were obtained from the Taiwan Water Supply Corporation. The control group consisted of people who died from other causes and the controls were pair-matched to the cases by sex, year-of-birth, and year-of-death. The adjusted odd ratios (95% confidence interval) were 0.79 (0.64-0.98) for the group with water calcium levels between 24.4 and 42.3 mg/liter and 0.58 (0.47-0.73) for the group with calcium levels of 42.4 mg/liter or more. The adjusted odd ratios were not statistically significant for the relationship between magnesium levels in drinking water and colon cancer. The results of the present study show that there is a significant protective effect of calcium intake from drinking water against colon cancer.

Geographic variations in mortality from motor vehicle crashes in Taiwan

Mortality from motor vehicle crashes within five urbanization categories in Taiwan between 1981 and 1990 was investigated. Sex-specific standardized mortality ratios (SMRs) were calculated within each urbanization category for motor vehicle crash deaths. Most urban areas demonstrated lower SMRs for both males and females. In contrast, most rural areas exhibited higher SMRs for both males and females. Both males and females demonstrated a significant linear relationship between decreasing urbanization and increasing SMRs for motor vehicle crash mortality. A variety of factors may underlie the inverse correlation between SMRs for motor vehicle crashes and urbanization category. These data are most useful in generating hypotheses for further studies to define specific etiological factors operating within urbanization categories.

Neurogenesis in juvenile and adult ring doves

Studies in songbirds suggest that neurogenesis during the first few years of life is related to song learning. In this study, we examined whether postnatal neurogenesis occurs in a nonsongbird, the ring dove (Streptoplia risoria), and whether it persists to old age. Twenty-four hours after a single intramuscular injection of [3H]thymidine, labeled cells were present in the brains, particularly in the lateral wall of the lateral ventricle of juvenile (3-month and 8-month) and adult (1-year to 8-year) doves. Two months after multiple [3H]thymidine injections, there were fewer labeled cells in the ventricular zone (VZ), but many labeled cells with neuronal morphology in the parenchyma of the forebrain; labeled cells were confirmed as neurons by using neuron-specific markers, microtubule-associated protein-2 (MAP-2) and anti-neuronal nucleus (NeuN). In general, new neurons were distributed in the forebrain without clustering in any particular nucleus. During the first year of life, however, neostriatum caudale and hyperstriatum, the regions known to be essential for proper integration of sensory cues and reproductive behavior, contained more new neurons than any other brain regions. These neuronal additions showed an age-related decline; the first reduction coincided with the dove's attainment of adult physical size (about 3 months old) and the second occurred when the dove would normally attain reproductive fitness (about 1 year old). A low level of forebrain neurogenesis persisted up to 8 years of age (the oldest animals studied). These observations suggest that neurogenesis in adulthood is widespread among birds but that the biological significance of adult neurogenesis in the ring dove remains to be determined.

Magnesium and calcium in drinking water and cerebrovascular mortality in Taiwan

The relationship between death from cerebrovascular disease and the levels of magnesium and calcium in drinking water was examined using an ecological design. The study area consisted of 227 municipalities in Taiwan. Data on the levels of magnesium and calcium in drinking water have been collected from the Taiwan Water Supply Corporation (TWSC). These levels of magnesium and calcium were compared using the standardized mortality ratios (SMRs) for cerebrovascular disease (1981-1990). A statistically significant inverse relationship was present between cerebrovascular mortality and levels of both magnesium and calcium after adjusting for urbanization index. After adjustment for calcium levels in drinking water and urbanization index, the weighted multivariate-adjusted regression coefficient indicated a decrease of 0.248 in the standardized mortality ratios (SMRs) for every 100 mg/L increase in magnesium levels in drinking water. The results from this study strengthen the hypothesis that magnesium in drinking water helps to prevent death from cerebrovascular disease.

Reciprocal talk between the auditory thalamus and the hypothalamus: an antidromic study

In this study we sought to validate physiologically the hypothalamus afferent projections from the auditory thalamus previously identified with tract tracing techniques in the ring dove. In total, we recorded the responses of 628 units in the nucleus ovoidalis (Ov) and its shell region to electrical stimulation applied to anterior hypothalamus and ventromedial nucleus. Ninety-six acoustic units in the shell region displayed good antidromic responses, confirming this region's axonal projections into these nuclei of the hypothalamus. Orthodromic responses (143 units) recorded in the Ov-Ov shell region suggest on the other hand reciprocal projections from the hypothalamus back to the auditory thalamus.

Respiratory and irritant health effects of a population living in a petrochemical-polluted area in Taiwan

Reported herewith are the results from an ongoing study of outdoor air pollution and the health of persons living in the communities in close proximity to petrochemical industrial complexes. To determine if there is an excess of adverse health outcomes in the population exposed to petrochemical industrial emissions, a health survey was undertaken in 1996 in this area and in one reference area which has no local industrial emissions. The subjects were 436 adults (30-64 years of age) living in the Sanwei area (exposed area) and 488 in Taicei (reference area). For several indicators of respiratory health, including cough, wheezing, and chronic bronchitis, the prevalence rates were not significantly different between the study and the control populations. Acute irritative symptoms (eye irritation, nausea, throat irritation, and chemical odor perception) were significantly more common in the exposed area, particularly perception of chemical odors (84.6% vs 2.1%). It is concluded that exposure to petrochemical air emissions may be associated with increased rates of acute irritative symptoms. Future studies are needed to identify the potential role of petrochemical industrial emissions (particularly volatile organic compounds) in the genesis of acute irritative symptoms in a nearby petrochemical industrial area.

Effect of inhibitors of poly(ADP-ribose) polymerase on the induction of GRP78 and subsequent development of resistance to etoposide

We have recently demonstrated that cell lines deficient in poly(ADP-ribose) synthesis due to deficiency in the enzyme poly(ADP-ribose) polymerase (PADPRP) or depletion of its substrate NAD+ overexpress GRP78. Furthermore, this overexpression of GRP78 is associated with the acquisition of resistance to topoisomerase II-directed drugs such as etoposide (VP-16); (S. Chatterjee et al., Cancer Res., 54: 4405-4411, 1994). Thus, our studies suggest that interference with NAD+-PADPRP metabolism could provide an important approach to (a) define pathways of GRP78 induction, (b) study the effect of GRP78 on other cellular processes, (c) elucidate the mechanism of GRP78-dependent resistance to topoisomerase II targeted drugs, and (d) modulate responses to chemotherapy in normal and tumor tissues. However, in the in vivo situation, it is impractical to interfere with NAD+-PADPRP metabolism by mutational inactivation of PADPRP or by depletion of its substrate NAD+. Therefore, we have examined several inhibitors of NAD+-PADPRP metabolism including 3-aminobenzamide, PD128763, and 6-aminonicotinamide for their ability to reproduce the results obtained with cell lines deficient in NAD+-PADPRP metabolism relative to the induction of GRP78 and subsequent development of resistance to VP-16. Our studies show that 6-aminoicotinamide treatment is highly effective in the induction of GRP78 and subsequent development of resistance to VP-16, whereas treatment with 3-aminobenzamide or PD128763 does not induce GRP78 and thus does not result in VP-16 resistance.

Poly(adenosine diphosphoribose) polymerase in peripheral blood leukocytes from normal donors and patients with malignancies

A two-color flow cytometric technique was developed to analyze poly(ADP-ribose) polymerase (PADPRP) in different individuals as a function of different physiological or pathological conditions and to establish the basis for determining whether enzyme deficiency may predispose to degenerative or malignant disorders. Peripheral blood granulocytes were devoid of enzyme activity, whereas mononuclear cells had variable amounts. PADPRP was highest in B cells, intermediate in T cells, and lowest in monocytes. This pattern of enzyme distribution and relative enzyme content of different types of cells was remarkably constant in normal subjects. In a series of 66 normal donors there was no significant biological variation in enzyme content as a function of age, race, or sex. The mean PADPRP values in peripheral blood mononuclear cells from 81 random patient samples obtained from an ambulatory oncology clinic did not differ significantly from normal subjects. However, groups of patients with breast cancer, lymphocytic malignancies, and esophageal cancer were observed to have below normal levels for peripheral blood mononuclear cell PADPRP.

Sex differences in cell proliferation in the ventricular zone of young ring doves

Cell proliferation in the ventricular zone was studied in 3-month-old ring doves, using [3H]-thymidine as the marker for DNA synthesis and hence cell division. We found sex differences in the rate of cell proliferation on the plane of preoptic area in these immature doves whose gonads were just undergoing changes.

Induction of M(r) 78,000 glucose-regulated stress protein in poly(adenosine diphosphate-ribose) polymerase- and nicotinamide adenine dinucleotide-deficient V79 cell lines and its relation to resistance to the topoisomerase II inhibitor etoposide

Cell lines deficient in poly(ADP-ribose) synthesis due to enzyme deficiency (ADPRT54 and ADPRT351) or substrate deficiency (N2, N3, and N4) are resistant to topoisomerase II-directed agents, including etoposide (VP-16), N-[4-(9-acridinylamino)-3-methoxyphenyl]methanesulfonamide, and Adriamycin, relative to the effect of these agents on parental V79 Chinese hamster cells. Resistance is stable in the ADPRT54 and ADPRT351 cell lines, whereas resistance in the N2, N3, and N4 cell lines occurs when the cells are grown in nicotinamide-deficient medium to produce a state of NAD deficiency. However, sensitivity to VP-16 reverts to normal when cellular NAD levels return to control levels during growth in nicotinamide-containing complete medium. Poly(ADP-ribose) polymerase-deficient cell lines show constitutively increased levels of a protein at M(r) 78,000 on Coomassie blue-stained, sodium dodecyl sulfate-polyacrylamide gels that was subsequently confirmed with monoclonal antibodies to be M(r) 78,000 glucose-regulated stress protein (GRP78). Similarly, N2, N3, and N4 cells show induction of GRP78 under nicotinamide-deficient conditions. Induction of GRP78 is associated with elevated levels of GRP78 mRNA and appears to be regulated at the transcriptional level. When N3 cells with deficiency of poly(ADP-ribose) synthesis due to NAD deficiency are shifted to complete, nicotinamide-containing medium, they restore their NAD content, undergo a decrease in GRP78 levels, and regain sensitivity to VP-16. When V79 cells are shifted to nicotinamide-deficient medium they undergo a reduction in NAD content, followed by a progressive elevation in GRP78 levels, and they subsequently become increasingly resistant to VP-16. These studies demonstrate a clear association between deficiency of the NAD-poly(ADP-ribose) synthesis system, induction of GRP78 synthesis, and resistance to VP-16.

Proposed pathways for vocal self-stimulation: met-enkephalinergic projections linking the midbrain vocal nucleus, auditory-responsive thalamic regions and neurosecretory hypothalamus

In this study, we have investigated the neuroanatomical pathways that may underlie the influence of a female bird's vocal behavior upon her own reproductive endocrine response. We traced the ascending efferent projections of the midbrain vocal control nucleus, the intercollicularis (ICo), using an anterograde tracer, PHAL, delivered by iontophoretic application. We found labelled terminal fields in the anterior regions of the hypothalamus that contained luteinizing hormone releasing hormone- (LHRH) immunoreactive neurons. We injected into the LHRH-rich anterior medial hypothalamus (AM) the retrograde tracer, fluoro-gold, to verify the results of PHAL anterograde tracing and examine whether retrogradely labelled neurons in the ICo can be stained with met-enkephalin antiserum by the immunohistochemical method. Of the retrogradely labelled neurons in the medial division of ICo (mICo), between 5% and 15% were found to be met-enkephalin-immunoreactive positive perikarya. Our data suggest that axonal projections into the anterior medial hypothalamus may arise in part from enkephalin-immunoreactive neurons in the medial ICo. The mICo neurons distributed along the medial border of the midbrain auditory nucleus give rise to projections into the posterior medial hypothalamus (PMH) via synapses within the shell region of thalamic auditory nucleus, ovoidalis (Ov). We conclude that in the ring dove, the medial division of the vocal control nucleus, by virtue of its connection with the auditory thalamus and neurosecretory hypothalamus, is in a position to exert influence on endocrine response partly through enkephalinergic systems. Implications of similar connections in other species are discussed.

Avian auditory pathways show met-enkephalin-like immunoreactivity

Pathways associated with a recently defined region of the avian auditory thalamus, the shell of the nucleus ovoidalis (Ov), were examined for met-enkephalin immunoreactivity. The presence of enkephalin-like immunoreactive (ELI) perikarya within the medial margin of the inferior colliculus (ICM), afferent to the Ov shell, implicated ICM as a source of ELI fibers within the Ov shell and tract. The shell also contained ELI perikarya and its targets, including the ventromedial hypothalamus and caudoventral paleostriatal complex, were characterized by ELI fields. These data suggest that enkephalinergic auditory pathways, in parallel with traditionally recognized auditory projections, target regions of the avian basal forebrain.

Social condition affects the courtship behavior of male ring doves with posterior medial hypothalamic lesions

Following bilateral lesions to the posterior medial hypothalamus (homologue of the mammalian ventromedial nucleus), adult male ring doves regain full courtship behavior and the ability to stimulate female egg-laying when housed continuously with females. Males with PMH lesions housed singly and only tested periodically with females continue to show deficits in courtship. These findings suggest that the social environment present in adulthood itself can directly influence recovery from brain lesions. They also demonstrate the importance of PMH in the mediation of male ring dove courtship behavior.

Auditory-responsive units in the midbrain vocal nuclei in the ring dove (Streptopelia risoria)

The avian midbrain vocal control nucleus, n. intercollicularis (ICo), receives inputs from midbrain auditory nucleus and from a subdivision of auditory thalamus, suggesting a possibility of auditory response units in the ICo. Using single-unit recordings, we explored auditory response units throughout the dorsomedial midbrain of female ring doves under deep general anesthesia (acute preparation). We found exclusively in the ICo, units that responded preferentially to taped courtship coos of conspecifics (male or female coos) and units that responded to specific frequencies present in coos. Units in the midbrain auditory nucleus also responded to these auditory stimulation in a tonotopic fashion, and were responsive to tone burst as well. The results, along with data from other experiments, suggest that species-specific sound responsive units within the ICo may mediate acoustically facilitated female coos and endocrine responses of the ring dove.

The shell region of the nucleus ovoidalis: a subdivision of the avian auditory thalamus

The connectivity of a region surrounding the established thalamic auditory nuclei, n. ovoidalis (Ov) and n. semilunaris parovoidalis (SPO), was explored in the ring dove by using the anterograde tracers, Phaseolus vulgaris leucoagglutinin (PHAL) and biocytin, and the retrograde tracer, fluorogold. The Ov-SPO surround received a projection from a cell group along the interface of the auditory midbrain and the n. intercollicularis, as revealed with PHAL and biocytin, and was composed of neurons exhibiting a common morphology. These features and the presence of overlapping projections from different portions of the Ov-SPO surround suggest that this region comprises a functionally discrete area, which we term the Ov shell. Single unit recording within the shell established the existence of acoustically responsive units. Both PHAL and fluorogold labeling revealed a robust projection from the Ov shell to the caudomedial hypothalamus. Major telencephalic projections of the shell terminated within the ventral paleostriatal complex, "end-zones" of the field L, the caudomedial hyperstriatum ventrale, and regions immediately dorsal and lateral to the auditory neostriatum. Except for a portion of the shell bordering medial ovoidalis, PHAL injections into the shell also labeled fibers within the caudolateral neostriatum and along the lateral neostriatal rim. The connectivity of the Ov shell suggests that this region may integrate auditory pathways with brain regions associated with endocrine mediated behavior. In addition, the shell may constitute a source of converging input to several levels of central auditory pathways.

Role of catecholamines in the courtship behavior of male ring doves

The role of catecholamines in the expression of male courtship behavior in ring doves was examined using central administration of pharmacological agents. Males treated with 6-hydroxydopamine or U-14,624, which depleted norepinephrine (NE) levels in the preoptic-hypothalamic area, showed increased levels of bow-coo and nest-coo displays. Conversely, males treated with tyramine or desipramine, which elevated NE levels in the preoptic-hypothalamic area, showed decreased levels of bow-coo and nest-coo displays. Drug-induced changes in dopamine levels were not consistent with any changes in behavior. This suggests that in the male ring dove NE in the preoptic-hypothalamic area is important in the expression of courtship displays.

Alkylating agent hypersensitivity in poly(adenosine diphosphate-ribose) polymerase deficient cell lines

Starting with the V79 cell line, two poly(ADP-ribose) polymerase deficient mutants, designated ADPRT 54 and ADPRT 351, had been shown to be hypersensitive to x- and UV-irradiation and to topoisomerase I inhibitors but to be resistant to topoisomerase II inhibitors (Chatterjee, S.; Cheng, M. F.; Berger, N. A. Hypersensitivity to clinically useful alkylating agents and radiation in poly(ADP-ribose) polymerase-deficient cell lines. Cancer Commun. 2:401-407;1990). We now report that these mutants were hypersensitive to a series of different alkylating agents, including alkylsufonates, alkylnitrosoureas, and nitrosoguanidine. In addition, they were hypersensitive to the UV-mimetic agent 4-nitroquinoline-1-oxide. Our findings provide strong evidence that poly(ADP-ribose) polymerase was involved in the repair of alkylating agent induced DNA damage as well as in the damage induced by UV- and x-irradiation and radiomimetic agents. The poly(ADP-ribose) polymerase deficient cell lines showed a marked decrease in the shoulder region of their survival curves, suggesting that poly(ADP-ribose) polymerase was involved in the repair of alkylating agent induced sublethal damage.

Hypersensitivity to clinically useful alkylating agents and radiation in poly(ADP-ribose) polymerase-deficient cell lines

Mutant V79 Chinese hamster cell lines, deficient in poly(ADP-ribose) polymerase activity, were previously shown to be significantly resistant to etoposide, a topoisomerase II inhibitor, and hypersensitive to camptothecin, a topoisomerase I inhibitor (Chatterjee, S.; Trivedi, D.; Petzold, S.J.; Berler, N.A. Mechanism of epipophyllotoxin-induced cell death in poly(adenosine diphosphate-ribose) synthesis-deficient V79 Chinese hamster cell lines. Cancer Res. 50:2713-2718, 1990 and Chatterjee, S.; Cheng, M.F.; Trivedi, D.; Petzold, S.J.; Berger, N.A. Camptothecin hypersensitivity in poly(adenosine diphosphate-ribose) polymerase-deficient cell lines. Cancer Commun. 1:389-394; 1990). We have now demonstrated hypersensitivity of these mutant cell lines, designated ADPRT 54 and ADPRT 351, to a variety of antitumor agents including melphalan, BCNU, mitomycin, and bleomycin. They are also hypersensitive to UV- and x-irradiation. These mutants, however, are significantly resistant to the topoisomerase II-targeted DNA intercalators, Adriamycin and m-AMSA. Our results strongly suggest that inhibition of poly(ADP-ribose) polymerase could be useful to potentiate the cytotoxicity of a variety of currently available antitumor drugs.

Camptothecin hypersensitivity in poly(adenosine diphosphate-ribose) polymerase-deficient cell lines

Mutant cell lines, derived from the Chinese hamster V79 cell line, deficient in poly(adenosine diphosphate-ribose) polymerase activity, and previously shown to be resistant to topoisomerase II inhibitors, were found to be hypersensitive to camptothecin, a topoisomerase I inhibitor. In all the cell lines, camptothecin induced dose-dependent protein-associated DNA single-strand breaks and sister chromatid exchanges. The increased sensitivity to camptothecin-induced cytotoxicity was not associated with an increase in DNA single strand breaks or sister chromatid exchanges. These results suggest the absence of any direct causal relation between (1) camptothecin induced sister chromatid exchanges and cytotoxicity or (2) camptothecin induced DNA strand breaks and cytotoxicity. The hypersensitivity of these mutant cell lines to camptothecin suggests that poly(adenosine diphosphate-ribose) polymerase is involved with topoisomerase I in modulating camptothecin induced cytotoxicity.

Behavioral stimulation of ovarian growth

The present study was conducted to test the following hypothesis: male courtship induced egg-laying behavior in the female ring dove is mediated by the female's nest-coo display which feeds back to stimulate her ovarian system through the mechanisms of audio- and proprioceptive feedback. In Experiment I, females were exposed to 24 hr male courtship and then received playback of different nest-coos in the absence of their mates. All playback was effective in inducing the females to perform nest-coo displays, but none as effective as presence of the courting males. A specified level of the female's nest-coo display determined whether there would be changes in follicular diameter. The females which received no playback after 24 hr pairing with the male (control) did not show any change in the follicular diameter. In Experiment II, females were deafened by removal of cochleae and upon recovery paired with males. Half of those deafened females performed nest-coo displays and subsequently laid clutches. The others failed to perform the display and did not lay. We conclude that both proprioceptive feedback and audio-feedback must be involved to yield maximal stimulation of follicular growth by the female's nest-coo display.

Retrograde HRP demonstration of afferent projections to the midbrain and nest calls in the ring dove

Midbrain control of vocalization was evaluated in the ring dove by determining the major afferent inputs with retrograde tract tracing technique. Horseradish peroxidase was infused into various portions of the nucleus intercollicularis, an estrogen concentrating area, which disrupts nest calls when lesioned and induces the vocalization when stimulated by estrogen. Most labelled cell bodies were found in the archistriatum, including a region homologous to the mammalian amygdala.

Ascending vocalization pathways in the female ring dove: projections of the nucleus intercollicularis

Nest-coo (courtship) vocalization is an estrogen-dependent component of a sequence of behaviors leading to egg-laying in the ring dove (Streptopelia risoria). Implantation of estrogen in the nucleus intercollicularis of ovariectomized females restores the ability to produce nest-coos. Lesion of n. intercollicularis specifically disrupts nest-cooing and inhibits follicular development. We used anterograde transport of tritiated leucine to identify regions that receive input from n. intercollicularis. As a control, isotope was injected in an auditory nucleus (nucleus mesencephalicus lateralis, pars dorsalis) neighboring the n. intercollicularis. A strong projection to the nucleus was observed, demonstrating a potential interaction between auditory and vocalization systems at the level of the midbrain. Local projections of n. intercollicularis were observed in midbrain and hind brain nuclei including the nucleus tegmenti pedunculo-pontinus, pars compacta and nucleus papillioformis. A conspicuous projection ascended centrally via the mesencephalic central gray. Proceeding rostrally, this pathway was traced to the nucleus periventricularis magnocellularis and tissue surrounding it. At its rostral extent, the pathway was found to project to the nucleus preopticus medialis, the anterior medial hypothalamus, and the lateral hypothalamus. These results are consistent with the possibility of a nucleus intercollicularis projection to regions that regulate reproductive function.

Breeding experience modulating androgen dependent courtship behavior in male ring doves (Streptopelia risoria)

Courtship behavior of reproductively experienced males was compared with that of age-matched inexperienced males before and after castration and during treatments with hormones (testosterone propionate and estradiol benzoate). Inexperienced males displayed significantly lower levels of nest-oriented courtship, the nest-cooing (nest-soliciting) and wingflippings; however, agonistic courtship, the bow-cooing, was not affected by breeding experience. The lower level of nest-cooing display in the inexperienced males persisted even when their circulating level of androgen as measured by RIA was no different from that of experienced males. Estrogen treatments, however, produced no group difference in levels of nest-coo display. These results were discussed in the context of hormone-behavior relationships.

Female cooing promotes ovarian development in ring doves

In female ring doves (Streptopelia risoria), hearing their own coos promoted greater follicular growth than hearing males coo, as demonstrated by the playback of various coos to experimentally muted females, under normal conditions. This difference in follicular growth suggests that the females' own cooing, not the males' cooing, stimulates the ovarian response.