Risk factors for diarrhoeal deaths: a case-control study at a diarrhoeal disease hospital in Bangladesh

The study of diarrhoeal mortality risk has been limited to descriptive epidemiological investigations. This is the first case-control study in this area, and our results show that certain risk factors are predictive of diarrhoeal deaths. We have compared the disease history, associated complications, signs, symptoms and laboratory values of 346 patients who died on the medical wards of Dhaka Hospital and that for 346 matched controls to identify the risk factors for mortality. Patients presenting with oedema, severe dehydration or convulsion were found to have a risk of mortality two times higher than controls. Several laboratory results were compared by a matched pair analysis, demonstrating that hyponatraemia (less than 130 mmol/L), hypobicarbonaemia (less than 20 mmol/L) and raised anion gap (greater than 14.9 mmol/L) were moderately associated with mortality. However, hypoproteinaemia (less than 50 gm/L) was strongly associated. For children less than 10 years of age, both hyper- and hyponatraemia were found to be associated with mortality, and the nutritional status of the children modified the effect of hypernatraemia on diarrhoeal mortality. The strong association between diarrhoeal death and hypoproteinaemia may be due to the effect of the pre-existing malnutrition of these patients and/or their loss of protein during shigella infection. The various risk factors that we have identified could be used as a prognostic guide by physicians treating such patients.

Epidemiological differences between cholera due to multiple antibiotic resistant and multiple antibiotic sensitive Vibrio cholerae infection

The appearance of cholera caused by multiply antibiotic resistant Vibrio cholerae in Bangladesh provided an opportunity to compare epidemiological features of infection caused by resistant and by sensitive V. cholerae. A prospective study was carried out using 46 families of hospital in-patient cholera cases due to resistant V. cholerae and 11 families of hospital cases due to sensitive V. cholerae and nine cases of cholera due to resistant and six cases due to sensitive V. cholerae detected in the neighbourhoods of hospital patients. All families were visited daily during ten days for cultures of rectal swabs, samples of domestic water and for history of diarrhoea. The results showed no significant difference in secondary infection and case rates in contacts of hospital cholera cases due to resistant and sensitive V. cholerae. However, the secondary infection rate (57%) in contacts of cases due to resistant V. cholerae detected from the neighbourhoods of hospital cases was significantly higher (p less than 0.05), than in the neighbourhood case-contacts (29%) of cases due to sensitive V. cholerae. The mean duration of diarrhoea in untreated resistant V. cholerae cases who were contacts of hospital cases (3.3 days) was significantly longer (p less than 0.05) than that of untreated sensitive V. cholerae (2.2 days). Higher isolation rates of V. cholerae were obtained from water sources used by cholera cases due to resistant V. cholerae, than from sources used by cases due to sensitive V. cholerae, but the differences were not statistically significant (p greater than 0.05). The study suggests that resistant V. cholerae poses an additional threat through a higher secondary infection rate and by causing illnesses of longer duration.

Fourteen years of shigellosis in Dhaka: an epidemiological analysis

We examined whether the proportion of Shigellae patients among diarrhoeal cases, the distribution, species, case-fatality rates and hospital visits changed over time in Dhaka. We isolated 19639 Shigella strains from 822812 diarrhoea cases treated at the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), between 1969 and 1982. The number of cases increased from 209 (2.5%) in 1969 to 4833 (7.7%) in 1976. Extrapolating from a 4% vigorous systematic sample of ICDDR,B hospital visits shigellosis cases and their proportion among diarrhoea cases increased to more than 9500 (12.0%) in 1981. The prevalence of various shigellae species altered over time. For example: in 1969 Shigella flexneri predominated in 74% of all Shigella cases; in 1973 Shigella dysenteriae accounted for 56%, and in 1981 Shigella flexneri again predominated (75%). More than 20% of all Shigella isolations were from infants: 60% in males and 40% in females. Over 7% of severe cases of Shigella infection referred from the outpatient department and admitted for treatment died. Nearly 40% of all the Shigella deaths were in infants of less than a year old while 49% were in 1-4 year old children. Increasing prevalence of shigellosis appears to be an important cause of diarrhoea in Dhaka especially among children. Areas with poor sanitation and water supply had higher prevalence. However, hospitalized cases represented a fraction of the actual problem. Resistance to antibiotics appears to be increasing and the development of new drugs and preventive methods within economic reach of less developed countries are crucial for reduction of the disease and related deaths.

Epidemiology and serology of Giardia lamblia in a developing country: Bangladesh

The age-specific prevalence of Giardia lamblia was determined in two Bangladeshi villages and malnourished children in hospital in Dhaka City. Age-specific acquisition rates, the duration of infection and age-specific sero-positivity to (immunofluorescent assay) G. lamblia trophozoites were determined. Infection was acquired early (less than one year) and in 16% of infected children persisted for longer than three months. Prevalence was higher in 5 to 10-year-old village children (21%) and one to five-year-old malnourished children (51%). Over 40% of the children much less than 7 years acquired G. lamblia within 18 months; acquisition rates did not change with age. Positive antibody titres were acquired between six months and one year and the prevalence of sero-positivity remained high in all age groups No association was found between positive antibody titres and positive stool examinations. In developing countries serum antibodies are useful epidemiologically, but are not diagnostic in the individual patient.

Presence of vibrios in surface water and their relation with cholera in a community

During an epidemic of cholera we simultaneously cultured water from 30 important ponds, tanks and rivers of Dhaka city, to determine the role of surface water as a reservoir of Vibrio cholerae and nonagglutinating (NAG) vibrios and whether their presence or absence can be used as an indicator of a cholera epidemic in the community. Out of 4.016 samples 1216 (30.3%) were positive for NAG vibrios and one (0.025%) for Vibrio cholerae. Ponds showed a higher rate of NAG isolation (31.6%) than did rivers (21.9%). NAG group II constituted 87% and group V 10% of all positives. There were mild-to-moderate seasonal variations in isolation rates. The NAG isolation rate from water was related to the incidence of hospitalized NAG diarrhoea cases, but not to simultaneous cholera cases. Surface water does not appear to be an efficient natural reservoir of Vibrio cholerae, as it is for NAG vibrios. The absence of V. cholerae or presence of NAG vibrios in public surface water sources has no relationship with the extent of cholera cases present in a community.

Nutritional ocular diseases and their association with diarrhoea in Matlab, Bangladesh

The prevalence of visual defects, especially from causes associated with nutritional deficiencies, and their relation to diarrhoea in rural Bangladesh have been studied. A trained physician and a team of health workers examined visual defects in 149 villages, with a total population of 182 976. According to WHO classification, night blindness (XN) was found in only 0.03 persons/1000 population and 0.04 were found to have conjunctival xerosis (XIA) and Bitot's spot (XIB). Corneal xerosis (X2, X3A, X3B) also was found in 0.04 persons/1000. Night blindness combined with conjunctival xerosis and Bitot's spot (XN + XIA + XIB) was present in 1.69 persons/1000 and all combined stages of active xerophthalmia were seen in 0.06 persons/1000. Xerophthalmia prevailed up to age 19 years. Males had a significantly higher (2.9) incidence/1000 than did females (1.2). The total rate of keratomalacial scar for all ages was 0.31 persons/1000, while corneal opacity from other causes was seen in 2.25 persons/1000 population. More than 2.06 persons/1000 had ocular manifestations of one or more vitamin A deficiencies, while 4.47 persons/1000 had other ocular diseases, except for cataracts. Only 12.0% of all the corneal scars (XS) were due to keratomalacia. History of night blindness is a good indicator of vitamin A deficiency. In 96% of cases, night blindness was associated with conjunctival xerosis and Bitot's spot (XN + XIA + XIB). The onset of approximately 86% of cases of corneal xerosis (X2, X3A, X3B) and night blindness associated with conjunctival xerosis and Bitot's spot (XN + XIA + XIB) was related to diarrhoea.

Breastfeeding, growth and diarrhoea in rural Bangladesh children

It has been observed that breastfeeding protects infants from many illnesses. We examined whether breastfeeding alone or with a supplement maintained normal growth and whether the incidence of diarrhoea was different in the two groups. The study was conducted on 223 children in a rural area. Anthropometric measurements were obtained every month up to 12 months and then every 3 months. The history of feeding was recorded. The mothers were visited weekly to record information on diarrhoeal illness. Homemade supplements were used. The average weight of exclusively breastfed children was not significantly different from that of those who were breastfed with supplements. The average weight paralleled the Harvard standard up to the 4th month, and the increase in height showed the same pattern. During the first year the incidences and duration of diarrhoeal attacks were higher in the exclusively breastfed children than in the supplemented groups. On average there were 3.2 attacks of diarrhoea per child per year and the average duration was 15.9 days per child per year during the first 2 years.

Changes in the trend of shigellosis in Dhaka: family study on secondary infection, clinical manifestation and sensitivity pattern: 1980

The incidence of shigellosis and the death rate have increased and the resistance of shigellae to antibiotics has changed in Dhaka during our experiences. In 1980, we investigated the secondary infection and case rates, infection to case ratio, duration of illness, excretion of shigellae and antibiotic sensitivity pattern in 100 families with cases of shigellosis, culturing rectal swabs obtained by home visits for a 10-day period. Standard methods were used for culture and sensitivity tests. The over-all secondary infection rate in contacts was 27.3% and the case rate 10.7%. The rates were higher for Shigella flexneri than for Sh. dysenteriae. When the index cases were nought to four years old the secondary infection and case rates were higher than when index cases were older. Contacts aged nought to four years had highest attack rates. The average duration of excretion of Sh. flexneri was 4.5 and Sh. dysenteriae 2.6 days. Illness was one day longer for Sh. dysenteriae than for Sh. flexneri. Cases of shigellosis in hospital had higher rates of fever and blood in stool than those who were not in-patients. 40% of Sh. dysenteriae and 14% of Sh. flexneri were sensitive to tetracycline, 0 to 5% to streptomycin and 100% to sulphamethoxazole, trimethoprim and gentamicin. Incidence of Sh. flexneri had increased in 1980 but that of Sh. dysenteriae remained the same as in 1973 although Sh. dysenteriae type 1 appeared to be less infective in 1980 than in 1973.

Clinical illnesses and causes of death in a Burmese refugee camp in Bangladesh

In 1978 almost 200 000 Burmese refugees entered Bangladesh. Thirteen camps were set up for refugees. Data for the camp at Leda is presented here. There were four medical clinics; including a diarrhoea clinic operated by the International Centre for Diarrhoeal Disease Research, Bangladesh. The four clinics recorded a total of 174 201 visits by the refugees, of which 28% were for watery diarrhoea, 32% for dysentery and 40% for other illnesses. Of 2321 diarrhoea stools cultured, 29.2% yielded pathogens of which 22% were Shigellae alone. Coliform count of water was extremely high. The death rate (89/1000/year) was higher than the birth rate (28/1000/year). Most of the deaths were among infants (640), children (357) and old people (131). Main causes of death were clinical diarrhoea (11.8%), fever (23%) and poor nutrition (52%). Prompt arrangements for food, identifying the vulnerable groups, and proper sanitation perhaps could have reduced the number of deaths considerably.

Value of stool examination in patients with diarrhoea

Findings of stool examinations in 1593 patients with diarrhoea due to a single enteric pathogen--enterotoxigenic Escherichia coli rotavirus, Shigella, Campylobacter jejuni, Vibrio cholerae 0:1, Entamoeba histolytica, or Giardia lamblia--were reviewed to determine how well they predicted the agent associated with the diarrhoea. Specimens were examined visually for blood and mucus, tested for pH, and examined under a microscope for the presence of red and white blood cells, parasites, and stool fat. Although visible blood was more common in specimens from patients infected with Shigella (51%) and Ent histolytica (39%) than in those from patients infected with other agents (6%; p less than 0.01), patients infected with Shigella were most likely to have numerous faecal leucocytes (greater than 50/high power field: 39% v 8% of all patients and 7% of patients infected with Ent histolytica, p less than 0.01 in both cases). Patients infected with enterotoxigenic E coli, rotavirus, V cholerae 0:1, or C jejuni had loose stools with fewer red or white cells. Patients infected with rotavirus and C jejuni were more likely to have acid stools with 3 to 4+ fat, but these findings were related to young age and breast feeding. Stool examination is most useful in establishing a diagnosis of dysentery and in helping to distinguish between patients infected with Shigella and Ent histolytica; it is of limited usefulness in discriminating between pathogens causing watery diarrhoea.

Classical Vibrio cholerae biotype displaces EL tor in Bangladesh

The EL Tor biotype of Vibrio cholerae caused all endemic and epidemic cholera in Bangladesh from 1973 until Sept. 3, 1982, when the first classical strain was isolated from a patient in Matlab. Since then the number of isolations of the classical biotype has increased very rapidly and spread to other districts, replacing the EL Tor biotype as the main epidemic strain. The classical strains isolated in the 1982 outbreak were indistinguishable by the standard tests from those isolated a decade ago and the very few isolates in 1979, 1980, and 1981. This suggests that beyond the taxonomic traits used to identify the classical and EL Tor strains, there may be other more crucial biological characteristics that have given this new strain an advantage over the existing strains. The mechanism by which a new biotype of V. cholerae 01 achieves such a crucial biological advantage to displace the existing strains may be a key point in control of the global spread of cholera.

Seasonality of classical and El Tor cholera in Dhaka, Bangladesh: 17-year trends

Data on the cholera patients admitted monthly to the ICDDR, B, hospital in Dhaka (Bangladesh) from 1964 through 1980 have been studied and analysed. Although Vibrio cholerae variant El Tor did not enter Bangladesh until 1963, it has completely displaced classical cholera since 1973. There have also been changes in seasonality, which are discussed.

The eltor cholera epidemic in Dhaka in 1974 and 1975

Surveillance of hospitalized cholera cases from 1970 to 1977 in Dhaka, a matched control study in 1974, and a neighbourhood control study in 1975 were carried out and show a change from classical cholera to the eltor biotype during this period. Of all the hospitalized cholera cases, 9.1% in 1972 and 99.9% in 1973 were due to the eltor biotype. In 1974 and 1975 the distribution of eltor cholera cases in the city was uniform, except for areas with modern sanitation whose residents were spared. The incidence rates of cholera per 1000 infants (under the age of 1 year) were 1.16 and 0.93 for 1974 and 1975, respectively. On the whole, children below 10 years and females between 15 and 44 years of age were the ones most affected with eltor cholera. Higher rates of diarrhoea and hospitalization were noted among the contacts with cholera cases, compared with non-cholera controls. Contracting cholera was significantly associated with eating in places away from home, especially at charitable feeding centres.

Endemic cholera in rural Bangladesh, 1966-1980

Since 1963, the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), formerly the Cholera Research Laboratory, has maintained a field station in Matlab to treat patients from a surveillance population of 240,000 who have cholera and other diarrheal diseases. Since 1966, the authors have analyzed hospital records of 7141 surveillance-area patients culture-positive for v. cholerae 01 to relate the seasonality, age and sex distribution, and geographic trends with hypotheses concerning transmission, immunity, and risk groups. From this review, they have found that: 1) children 2-9 years old and adult women are most commonly hospitalized for cholera; 2) V. cholerae 01 emerges simultaneously throughout the area of surveillance, with the early cases being of different phage types; 3) three patients were hospitalized twice for cholera compared with 29 expected on the basis of life-table analysis (p less than 0.01), suggesting that immunity to severe disease conferred by previous illness may be stable and long-lasting; 4) no constant relationship was found between the times of onset or peaks of the yearly cholera epidemic and the times of onset or peaks of the monsoon rains or river water levels; and 5) an outbreak of multiply antibiotic-resistant V. cholerae 01 infection documented in 1979 raises questions about the dissemination of resistance plasmids, antibiotic-use patterns, and the need for other drugs in addition to tetracycline. While little progress has been made in understanding the mode of transmission of v. cholerae 01, and in identifying practices for prevention, fluid therapy in this area has decreased the case fatality rate significantly and provides guidance for similar programs elsewhere.

Surveillance of patients attending a diarrhoeal disease hospital in Bangladesh

In October 1979 a surveillance system was set up at the International Centre for Diarrhoeal Disease Research, Bangladesh, Hospital at Dacca to study a 4% systematic sample of the 100 000 patients with diarrhoea who come to the hospital for care each year. From December 1979 to November 1980 inclusive, 3550 patients were studied. A recognised pathogenic organism was identified for 66% of patients screened for all pathogens, one-third of whom had a mixed infection with two or more agents. Enterotoxigenic Escherichia coli was the most common enteropathogen detected in all age groups (detection rate 20%), followed by rotavirus (19%), Campylobacter jejuni (14%), and Shigella (12%). Infants and young children (up to 5 years) were most often infected with rotavirus, enterotoxigenic E coli, and C jejuni and older children (5-14 years) had more infections with enterotoxigenic E coli, Shigella, and E histolytica. Surveillance has helped to define the range of disease among patients attending the Dacca Hospital. Sixty-five per cent of patients complained of watery diarrhoea, a presentation that was significantly more common in patients with Vibrio cholerae 0:1 (91%), enterotoxigenic E coli (78%), rotavirus (77%), and C jejuni (71%) than in all patients studied. Dysentery, defined as a history of diarrhoea with blood, was the presenting complaint of 20% of all patients but 55% of those with Shigella. Only patients with V cholerae 0:1 and enterotoxigenic E coli were at increased risk for severe dehydration. In addition surveillance has been used to identify areas where patient care can be improved and to generate new ideas for research.

Epidemiologic and clinical features of patients infected with Shigella who attended a diarrheal disease hospital in Bangladesh

The epidemiologic and clinical characteristics of 412 patients infected with Shigella from a systematic sample of approximately 100,000 patients attending Dacca Hospital, International Centre for Diarrhoeal Disease Research, Bangladesh, between December 1, 1979, and November 30, 1980, were reviewed. Shigella was isolated from 11.6% of the 3,550 patients in the sample and was the second most common isolate in patients over two years old. Two clinical presentations of shigellosis were found: (I) watery diarrhea occurring in younger children and associated with a shorter duration of illness and with more vomiting and dehydration and (2) dysentery with stool blood and abdominal pain. These different presentations may reflect two mechanisms in the pathogenesis of shigellosis or different stages of the disease. The most useful signs and symptoms for the diagnosis of shigellosis were stool with blood and abdominal pain in all patients and the absence of watery diarrhea and vomiting in patients over one year old. Simple visual inspection of stool for blood correctly identified 44% of all patients infected with Shigella.

Endemic focus of Fasciolopsis buski infection in Bangladesh

Stool surveys were conducted on children 2--10 years of age in 27 villages within Dacca District and around this index area (1,668 children were sampled), revealing an endemic focus of Fasciolopsis buski infection to the south and the east of Dacca District. In order to determine the seasonal variation in the total snail populations and the natural rate of F. buski infection in the snails, two species of planorbid snails, Segmentina (Trochorbis) trochoideus and Hippeutis (Helicorbis) umbilicalis, were periodically sampled for 12 months from a village endemic for F. buski infection. Gymnocephalous cercariae were found in S. (T.) trochoideus snails during August, September and October. The size of the snail population (n = 1,275) was significantly correlated with inches of rainfall (r = +0.62; P less than 0.05) and water temperature (r = +0.59; P less than 0.05). The natural infection rate of F. buski in the snails ranged from 0.5--2%. Snails from non-endemic areas were exposed to 3--10 miracidia. A total of 13 of 49 (27%) of H. (H.) umbilicalis and 6 of 14 (43%) of S. (T.) trochoideus had gymnocephalous cercariae present 4 to 6 weeks after exposure to miracidia. Thus, snail strain variation is unlikely to be a barrier to F. buski transmission.

Epidemiologic pattern of diarrhoea caused by non-agglutinating vibrios (NAG) and EF-6 organisms in Dacca

Non-agglutinating vibrios (NAG) and a new organism (EF-6) caused a severe diarrhoea epidemic in Dacca in 1976 and 1977. The common NAGs detected were groups II, V and VII which were present all the year round with peaks in the spring and postmonsoon seasons, while EF-6 attained its peak in March. NAG and EF-6 diarrhoeas occurred all over the city. The NAGs and EF-6 infected males twice as often as females and EF-6 more often affected the age group 0-4. The secondary attack rates in contacts of NAGs ranged from 10% to 25%; there were none in the EF-6 affected families. Open sources of water were often contaminated with NAGs and occasionally with EF-6. About half of the isolates from contacts and water sources were of groups other than the index case. Water was thought to be the vehicle of transmission.

Efficacy of short course antibiotic prophylaxis in controlling cholera in contacts during epidemic

During an epidemic of cholera, vaccination has limited applicability in controlling its spread. It has been seen that one out of every five to 10 V. cholerae-infected people develops diarrhoea severe enough to require hospital treatment. Most health authorities are concerned with this severely ill group in whom the majority of deaths occur. During the cholera epidemic of 1975 in Dacca two doses of tetracycline were administered to all family contacts of index cases. The control group of cholera cases did not receive the drug. The families were re-visited after 10-12 days and history of any diarrhoea and hospitalization was obtained. It was found that the subsequent diarrhoea or cholera cases occurring among the cholera contacts within 10-12 days were not different between the treated (13.5%) and the untreated (14.4%) groups. The occurrence of severe cases requiring hospitalization was, however, significantly reduced in the treated group (8.0% to 4.5%). In view of the emergence of V. cholera strains resistant to tetracycline, antibiotic sensitivity testing of epidemic strains would be needed before use of tetracycline for protecting cholera contacts as an immediate control measure.

Interruption of shigellosis by hand washing

High attack rates, increasing resistance to antibiotics and high mortality make shigellosis a serious problem. As Shigella is associated with poor hygiene we examined the effectiveness of a simple intervention, washing hands with soap and water, in checking the spread of the disease. The study population was comprised of confirmed cases of shigellosis. These and matched controls were followed up for 10 days. Several pieces of soap and earthenware pitchers for storing water were provided to the study families and they were advised to wash their hands with soap and water after defaecation and before meals. Compliance was monitored daily by observing the size of the soap and residual water. Rectal swabs of contacts of both the groups were obtained for culture. The secondary infection rate was 10.1% in the study group and 32.4% in the control group. The secondary case (symptomatic) rate was 2.2% in the study group and 14.2% in the control group. These results suggest that hand-washing has a positive interrupting effect, even in unsanitary environments.

Role of water and sanitation in the incidence of cholera in refugee camps

The purpose of this study was to determine the prevalence of cholera in two groups: (i) people using covered latrine and piped water; (ii) people using uncovered surface latrine and pond and tubewell water. The study population consisted of cholera cases admitted to the ICDDR, B hospital from three refugee camps. In the one camp with sanitation facilities, the cholera rate was 1.6 per 1,000, whereas in the two camps without facilities the rates were 4.0 and 4.3 per 1,000. Following demolition of the camps, the cholera rates decreased significantly in the camps geographical zones. Cholera was not totally eliminated, even in the one camp with sanitation facilities, suggesting that health education, as well as proper sanitation, is necessary to eradicate cholera.

The relationship of cholera to water source and use in rural Bangladesh

The cholera experience of a sample of families in a rural area of Bangladesh is reported in relation to water supply and use. Tanks were the primary source for 65% of families, canals for 20% and the river for 14%. The highest attack rate was associated with access to canal water (13%). Attack rates did not vary markedly according to the purpose for which a source was used. The importance of cultural patterns in water use is identified.

Microbiological surveillance of intra-neighbourhood E1 Tor cholera transmission in rural Bangladesh

The apparent failure of handpump tubewells to reduce the incidence of cholera among users in the flooded rural area of Bangladesh has stimulated interest in defining precisely the means of Vibrio cholerae transmission during localized outbreaks. Cholera-infected neighbourhoods were placed under intensive microbiological surveillance to pinpoint contaminated sources and subsequent infections. The results show that cholera transmission was via contaminated surface water, particularly water taken into households for cooking or drinking. Infections resulted from a daily dose not exceeding 10(5) organisms and the frequency of exposure appeared to be a major determinant of the infection rate. The importance of these data in environmental interventions and particularly in the provision of tubewells is discussed.

Effects of Substituted Pyridazinones (San 6706, San 9774, San 9785) on Glycerolipids and Their Associated Fatty Acids in the Leaves of Vicia faba and Hordeum vulgare

The fatty acids of the major glycerolipids from the leaves of Vicia faba and Hordeum vulgare plants treated with three different concentrations of pyridazinone derivatives were analyzed. These compounds showed multiple effects on the levels of lipids and pigments. At low concentrations, the primary effect of San 9785 was on the level of linolenic acid (18:3) in the galactolipids of V. faba, whereas the effect of San 6706 was primarily on the trans-Delta(3)-hexadecenoic acid (16:1) content in phosphatidylglycerol. At higher concentrations, the two compounds reduced the content of both fatty acids in the leaves. The results appear to indicate a differential effect of these herbicides on fatty acid accumulation and a difference in susceptibility of two fatty acids in the species examined. Electron microscopic studies revealed that two herbicides caused different abnormalities in V. faba chloroplast ultrastructure.

Distribution of a platinum anti-tumour drug in HeLa cells by analytical electron microscopy

The distribution of Pt in HeLa cell sections after cell treatment with cis-Pt(NH3)2Cl2 dissolved in dimethylsulphoxide was probed by analytical electron microscopy. Primary targets were the nucleolus and the inner side of the nuclear double membrane. Even after solvolysis in dimethylsulphoxide the drug reached similar sites. It is suggested that cell death may be due to Pt inhibition at the initiation sites of DNA synthesis.

Effect of brain stimulation on aldosterone secretion in the rhesus monkey (Macaca Mulatta)

The lateral hypothalamus, and various sites within the limbic system and frontal lobe of the rhesus monkey brain were electrically stimulated using chronically implanted electrodes. A considerble increase in plasma aldosterone levels was observed after stimulation of the lateral hypothalamic area, certain localized sites in the cingulate area, and lower medial parts of the frontal lobe. Inactive sites included most of the amygdala, hippocampus, and basal ganglia, together with other areas within the frontal lobe and cingulate gyrus. Stimulation of all active areas was followed by an increase in plasma renin activity. Plasma cortisol also increased considerably after hypothalamic stimulation but in the case of extra-hypothalamic sites the cortisol response was much less.

Effect of adrenergic blockade and dexamethasone on the aldosterone response to brain stimulation in the rhesus monkey

The increase in aldosterone and plasma renin activity (PRA) observed after stimulation of extrahypothalamic sites within the brain of the rhesus monkey was prevented by the prior administration of the beta-adrenergic blocking agent propranolol. alpha-Adrenergic blockade by phentolamine had no inhibiting effect. Propranolol only partially reduced the response of aldosterone to lateral hypothalamic stimulation in spite of inhibition of PRA; a partial reduction in aldosterone was also obtained from this site after dexamethasone treatment without any effect on PRA. It was concluded that the increase in aldosterone observed after extra-hypothalamic stimulation was mediated mainly through the renin-angiotensin mechanism whereas in the case of the hypothalamus, release of ACTH was also a contributory factor.

Galactolipid Synthesis in Vicia faba Leaves: I. Galactose, Glycerol, and Fatty Acid Labeling after CO(2) Feeding

The galactose, glycerol, and fatty acids of mono- and digalactosyl diglycerides (MGDG and DGDG) have been separated and analyzed for (14)C activity after (14)CO(2) feeding of Vicia faba leaf discs. Fully expanded and developing leaves were analyzed at time intervals following feeding during continuous illumination. In addition, fully expanded leaves were analyzed after similar times in complete darkness. In all cases, (14)C was incorporated very rapidly into galactose, whereas glycerol and fatty acids were labeled much more slowly and over a longer period of time. The data are consistent with the galactosylation of a diglyceride to MGDG which is in turn galactosylated to DGDG. The data suggest that the formation of diglycerides suitable for galactosylation to MGDG is slow in comparison to the galactosylation process. It is also suggested that DGDG may be formed from more than one pool of MGDG. The complete analysis of the (14)C incorporation into galactose appears to represent the only satisfactory method of comparing galactolipid synthesis by (14)C incorporation. Estimates of comparative rates of synthesis of MGDG and DGDG have been made on this basis.