Physical Fitness in Relation to Energy and Iron Status of Female College Students

A nutritional survey was conducted on 150 female college students (75 boarders and 75 day scholars) aged 18 to 23 years at the Punjab Agricultural University in Ludhiana, India. The mean weight, mid-upper-arm circumference, and triceps skinfold thickness were below normal, but the mean height and body fat were in the normal range. The body mass index showed that 50% of the subjects were normal, 21% were low normal weight, and 21% had a mild energy deficiency. The average daily consumptions of energy and of iron were 1,776 ± 22 kcal and 14.5 ± 0.2 mg, respectively; both were inadequate. The daily total energy expenditure was 1,824 ± 9 kcal, yielding a negative energy balance of 48 ± 10 kcal/day. The average haemoglobin and serum ferritin levels were below normal, while serum iron was in the low normal range. Low iron intake and haemoglobin levels confirmed an unsatisfactory iron status of the subjects. The combined deficiency of energy and iron appeared to have a worse effect on physical fitness than energy or iron deficiency alone.

Tuning the properties of pH responsive nanoparticles to control cellular interactions in vitro and ex vivo

Engineering the properties of nanoparticles to limit non-specific cellular interactions is critical for developing effective drug delivery systems. Differences between interactions with cultured cells and human blood highlights the need for appropriate assays.

The water method significantly enhances patient-centered outcomes in sedated and unsedated colonoscopy

Failure of cecal intubation when using air insufflation during scheduled unsedated colonoscopy in veterans prompted a literature search for a less uncomfortable approach. Water-related maneuvers as "adjuncts" to air insufflation were identified as effective in minimizing discomfort, although medication requirement was not reduced and willingness to repeat unsedated colonoscopy was not addressed. These adjunct maneuvers were combined with turning the air pump off to avoid colon elongation during insertion. Warm water infusion in lieu of air insufflation was evaluated in observational studies. Subsequent refinements evolved into the water method - a combination of air exclusion by aspiration of residual air to minimize angulations at flexures and a dynamic process of water exchange to remove feces in order to clear the view and aid insertion. In subsequent randomized controlled trials, the water method significantly reduced medication requirement, increased the proportion of patients in whom complete unsedated colonoscopy could be achieved, reduced patient recovery time burdens (sedation on demand), decreased abdominal discomfort during and after colonoscopy, enhanced cecal intubation, and increased willingness to repeat the procedure (scheduled unsedated). Supervised education of trainees and self-learning by an experienced colonoscopist were feasible. Lessons learned in developing the water method for optimizing patient-centered outcomes are presented. These proof-of-principle observations merit further research assessment in diverse settings.

Measurement of energy cost of selected household and farm activities performed by rural women

A nutritional study was carried out on 30 rural, low-income women, aged 25 to 35 years, in the village of Dhandra, Ludhiana District, Punjab, India, to measure the energy cost of selected household and farm activities. The mean weight, mid-upper-arm circumference, and triceps skinfold thickness were below the reference standards. A negative energy balance among the subjects indicated their poor energy status. The energy costs of selected household and farm activities were assessed by the Caltrac personal activity computer. The energy costs of household activities--making dough, making chapatis, grinding masala, hand pumping, washing utensils, sweeping, mopping, washing the floor, mud pasting, and washing clothes--were 0.0306, 0.0281, 0.0595, 0.0337, 0.0266, 0.0424, 0.0530, 0.0331, 0.0634, and 0.0453 kcal/kg/min, respectively. The energy costs of farm activities--collecting fodder, chaffing fodder, milking, making dung cakes, picking sag, harvesting wheat, bundling wheat, picking paddy, brooming paddy, and separating paddy--were 0.0472, 0.0372, 0.0530, 0.0270, 0.0337, 0.0623, 0.0374, 0.0411, 0.0370, and 0.0744 kcal/kg/min, respectively. All selected activities were categorized as light, except for grinding masala, mopping, mud pasting, harvesting wheat, separating paddy, and milking, which were categorized as moderate on the basis of Food and Agriculture Organization (FAO) physical activity ratios. The Caltrac gave lower values for the energy costs of most of the activities. Although it is simpler and less costly, the Caltrec must be calibrated against methods of measuring oxygen consumption for similar activities.

Iron and energy supplementation improves the physical work capacity of female college students

A nutritionally controlled study was conducted on two groups of 15 female college students aged 16 to 20 years, selected from Punjab Agricultural University, Ludhiana, Punjab, India. The girls were either anemic (hemoglobin 7.7 g/dl) but energy adequate (AEA), or anemic (hemoglobin 7.4 g/dl) and energy deficient (AED). The AEA group was given iron supplementation (60 mg iron/day) for 6 to 9 months along with 100 mg of ascorbic acid, and the AED group was given iron as well as energy supplementation for 3 months. There was a significant (p < .01) increase in weight, body mass index, mid-upper-arm circumference, and body fat in the AED group after iron-energy supplementation. Hemoglobin, serum iron, transferrin saturation, total iron-binding capacity, and unsaturated iron-binding capacity were below normal in both groups; however, after iron and iron-energy supplementation, there was a significant (p < .01) increase, and these indices were in the normal range. There was a significant (p < .01) increase in exercise time and maximum work load tolerance after iron and iron-energy supplementation. Combined energy and iron deficiency had a greater adverse effect on physical work capacity than energy or iron deficiency alone.

Serum ferritin as a measure of iron stores in the college girls

The average daily iron consumption of the college girls was 48 per cent of the recommended dietary allowances of ICMR (1990). The Hb level was below the normal value. The values of serum iron, transferrin saturation (TS) and unsaturated iron bearing capacity (UIBC) were in the normal range but near the lower margin. The TIBC was above the normal range. The serum ferritin values showed very poor iron stores. A highly significant (p < 0.01) correlation was observed between Hb, serum iron and TS with serum ferritin. There is a superiority of ferritin over other blood parameters as it indicates the liver iron stores, hence, a better predictor of iron deficiency status.

Heterotopic gastric tissue in the duodenal bulb

Heterotopic gastric tissue in the duodenal bulb is a rare congenital lesion. Its prevalence has been reported to be 0.5-2%. It must be differentiated from gastric metaplasia of the duodenal bulb because the two entities have different clinical implications. During one year, we found three cases of gastric heterotopia of the duodenal bulb. In one of the cases, active acid-secreting gastric mucosa was documented by performing the pentagastrin Congo red dye test. The differences between gastric heterotopia of the duodenal bulb and gastric metaplasia of the duodenal bulb have been discussed.

The Computer Programme “MSU Nutriguide: Asian Indian Foods” is Effective in Assessing Nutrient Intakes of Indian Populations

A nutritional study was conducted on 150 female college students aged 18 to 23 at the Punjab Agricultural University, Ludhiana, India, to evaluate the effectiveness of “MSU Nutriguide: Asian Indian Foods,” a computer programme for assessing nutrient intakes and total energy expenditure (TEE) of the Indian population. A non-significant difference between analysed and calculated values for energy, protein, iron, and ascorbic acid revealed that the intake of the nutrients calculated with the MSU Nutriguide was a correct assessment in most of the subjects. TEE estimation by MSU Nutriguide gives values based on age, height, weight, and four levels of physical activity (sleeping and light, moderate, and heavy activity), whereas prediction equations are based on the body weight of each subject and a single level of activity. Therefore, MSU Nutriguide can be efficiently used to assess the TEE of people in India.

In cirrhotic patients variceal bleeding is more frequent in the evening and correlates with severity of liver disease

BACKGROUND/AIMS

It has been observed that the portal pressure in cirrhotic patients shows circadian variation and is at a maximum at night. Our aims in this study were a) to evaluate the frequency of upper gastrointestinal (UGI) bleeding from esophageal/gastric varices or portal congestive gastropathy during the day, evening or night shift, and b) to correlate the frequency of bleeding during various shifts with severity of liver disease.

METHODOLOGY

At our institution, during the period from January 1997 to June 1995, 15,000 gastrointestinal (GI) endoscopic reports and consultations were evaluated. Episodes of bleeding due to portal hypertension (PH), i.e., esophageal varices, gastric varices or congestive gastropathy, were noted. The time of occurrence of bleeding from PH in various shifts, e.g., day shift (DS), evening shift (ES) or night shift (NS) was determined. The severity of liver disease was classified as A, B or C according to Child's classification.

RESULTS

There were 221 episodes of UGI bleeding due to PH in 144 patients. 75.5% of patients presented with hematemesis, whereas 24.5% presented with melena (p < 0.025). Bleeding started during the DS in 39/221 (17.6%), during the ES in 122/221 (55.2%), and during the NS in 60/221 (27.1%). There were 29 (13.1%) patients in Child's A, 75 (33.9%) in Child's B, and 117 (52.9%) in Child's C. Among the 122 bleeders during ES, 85 (69.6%) were in category C. It seems that in these patients UGI bleeding is more frequent during the ES compared to DS and NS (p < 0.0001; chi square; 95% CI: 0.52-0.58). Child's C patients are more likely to bleed during ES compared to Child's A or B patients (p < 0.0001; Odds Ratio: 4.8%; 95% CI: 2.7-8.5).

CONCLUSIONS

1) The majority of the cirrhotic patients with PH who develop UGI bleeding present with hematemesis rather than melena. 2) The bleeding in these patients is more likely to occur during the ES. 3) Child's C patients are more likely to bleed during the ES.

The safety of hot biopsy forceps in the removal of small colonic polyps

Nine hundred and seven polyps (mean size 3.7 mm; range 2-8) from 460 patients (mean age 67 years; range 34-94) were removed with monopolar electrocoagulation forceps ('hot biopsy forceps'). Sixty-three percent of the polyps were adenomatous and 36% were hyperplastic. In this series there were 3 cancers and 1 neurofibroma. About 42% of the polyps were in the sigmoid-rectum region; the rest were evenly distributed in the remaining part of the colon. There were no complications. Specifically there were no cases of perforation or massive bleeding after removal of these polyps. Within the guidelines mentioned, hot biopsy removal of small colonic polyps is safe.

Role of cAMP-dependent protein kinase in controlling aggregation and postaggregative development in Dictyostelium

We have examined the role of cAMP-dependent protein kinase (PKA) in controlling aggregation and postaggregative development in Dictyostelium. We previously showed that cells in which the gene encoding the PKA catalytic subunit has been disrupted (pkacat- cells) are unable to aggregate [S. K. O. Mann and R. A. Firtel (1991). A developmentally regulated, putative serine/threonine protein kinase is essential for development in Dictyostelium. Mech. Dev. 35, 89-102]. We show that pkacat- cells are unable to activate adenylyl cyclase in response to cAMP stimulation due to the inability to express the aggregation-stage, G-protein-stimulated adenylyl cyclase (ACA). Constitutive expression of ACA from an actin promoter results in a high level of Mn(2+)-stimulated adenylyl cyclase activity and restores chemoattractant- and GTP gamma S-stimulated adenylyl cyclase activity but not the ability to aggregate. Similarly, expression of the constitutively active, non-G protein-coupled adenylyl cyclase ACG in pkacat- cells also does not restore the ability to aggregate, although ACG can complement cells in which the ACA gene has been disrupted. These results indicate that pkacat- cells lack multiple, essential aggregation-stage functions. As the mound forms, high, continuous levels of extracellular cAMP functioning through the cAMP serpentine receptors activate a transcriptional cascade that leads to cell-type differentiation and morphogenesis. The first step is the induction and activation of the transcription factor GBF and downstream postaggregative genes, followed by the induction of prestalk- and prespore-specific genes. We show that pkacat- cells induce postaggregative gene expression in response to exogenous cAMP, but the level of induction of some of these genes, including GBF, is reduced. SP60 (a prespore-specific gene) is not induced and ecmA (a prestalk-specific gene) is induced to very low levels. Expressing GBF constitutively in pkacat- cells restores ecmA expression to a moderate level, but SP60 is not detectably induced. Overexpression of PKAcat from the Actin 15 (Act15), ecmA prestalk, and the PKAcat promoters in pkacat- cells result in significant aberrant spatial patterning of prestalk and prespore cells, as determined by lacZ reporter studies. Our studies identify new, essential regulatory roles for PKA in mediating multicellular development.

Expression of cAMP-dependent protein kinase in prespore cells is sufficient to induce spore cell differentiation in Dictyostelium

The activity of cAMP-dependent protein kinase (PKA) is required for proper development at several stages during the Dictyostelium life cycle. We present evidence that activation of PKA is rate-limiting for the differentiation of prespore cells to spores and that PKA activation may be the developmental trigger for sporulation. Strains that overexpress the gene encoding the catalytic subunit of PKA (PKAcat) or lack a functional regulatory subunit (rdeC strains) undergo rapid, heterochronic development. We show that overexpression of PKAcat in prespore cell is sufficient to directly induce expression of the spore maturation marker spiA and differentiation to spores, in a cell-autonomous manner. Moreover, overexpression of PKAcat in prespore cells can bypass a mutation that blocks an earlier developmental step to induce spiA expression. Our results suggest that the regulatory pathway in prespore cells between the activation of PKA and spiA induction/spore maturation is quite short and that PKAcat expression in prespore cells may mediate spore differentiation at the level of transcription. This induction of sporulation requires the prior activation of the prespore cell pathway. In addition, we show that beta-galactosidase activity expressed from a PKAcat promoter/lacZ reporter construct is highly enriched in the anterior prestalk A region during the tipped aggregate, slug, and early culminant stages and that this pattern switches abruptly to a prespore pattern at the time of spore maturation, supporting the proposed role of PKA in this process.

Enterokinase

Enterokinase is a glycoprotein and is now designated enteropeptidase (E.C.3.4.4.8.). It is present in the duodenal and jejunal mucosa. Pancreatic proteolytic enzymes are secreted as proenzymes. Enterokinase converts trypsinogen to trypsin in the duodenal lumen. Duodenopancreatic reflux of duodenal enterokinase may be important in the pathogenesis of experimental and clinical acute pancreatitis. Congenital enterokinase deficiency is a distinct clinical entity characterized by diarrhea, failure to thrive, hypoproteinemia, and edema. Acquired enterokinase deficiency may occur in some diffuse small bowel diseases. Steatorrhea of celiac spruce may be due partly to the fact that deficiency of secretin and cholecystokinin may interfere with the action of enterokinase. The interrelationship between secretin, cholecystokinin, enterokinase, and bile salts is not completely understood.

Impact of nutrition counselling and supplements on the mineral nutriture of rural pregnant women and their neonates

Sixty six young women from low and lower middle income groups selected from 8 villages of Ludhiana district in the first trimester of pregnancy were divided equally into Experimental (E) and Control (C) Groups, out of which only 60 subjects reached to the term. Folifer and calcium tablets were supplied to E group from second trimester till delivery along with regular medical supervision and nutrition education about additional nutrient needs. Intake of all the nutrients were less than the Recommended Dietary Allowances in the E and C groups during the third trimester. However, the requirement of iron, calcium, folic acid, vitamin B12, Vitamin D and ascorbic acid were met in group E due to supplementation. The Fe, Ca and Cu levels improved significantly during the third trimester in group E. The cord serum levels of Fe, Ca and Cu were also significantly higher in Group E. The relationships between maternal and cord blood levels of Fe, Ca and Cu were also significantly higher in Group E. The relationships between maternal and cord blood levels of Fe, Ca, Cu and Zn were significant, the co-efficients of correlation being 0.67, 0.92, 0.97 and 0.43, respectively. Serum Mn had an insignificant correlation with other minerals. The results indicated that 86.7, 94.7 and 44.8% variation (r2) in cord serum Ca, Cu and Fe levels was determined by the corresponding maternal serum levels. It is concluded that regular medical supervision, supplementation and nutrition education significantly improved the nutriture of the pregnant women and their neonates.

Impact of nutrition education and medical supervision on pregnancy outcome

Sixty Punjabi women from low and lower middle income groups were selected from eight villages of Ludhiana district. The supplements of iron, folic acid and calcium in the form of Folifer and Calcium Sandoz tablets were regularly supplied to experimental (E) group from second trimester onwards. A pamphlet about the diet during pregnancy was distributed to the E group along with four individual and three group contacts during the second half of pregnancy. The control (C) group was provided iron and folate supplements as per Government practice. Body height, weight, mid-upper arm circumference (MUA) and skinfold thickness of the subjects were recorded. Weight gained during pregnancy and post partum weight were also recorded and body mass index was calculated. In addition, crown heel length (CHL), birth weight (BW), skinfold thickness, MUA, head circumference (HC), Chest circumference (CC) and ponderal index (PI) of the neonates were recorded within eight hours of their birth. The gain in weight during pregnancy was 6.30 and 5.7 kg in E and C groups respectively. The study revealed that BW, CHL, skinfold thickness and PI of the newborns were significantly (p < 0.01) higher in E group. The mean BW of newborns in E and C groups was 2700 g and 2300 g, respectively. Weight gained during pregnancy had significant (p < 0.05) correlation to MUA, BW and skinfold thickness of the newborn.

cAMP-dependent protein kinase differentially regulates prestalk and prespore differentiation during Dictyostelium development

We and others have previously shown that cAMP-dependent protein kinase (PKA) activity is essential for aggregation, induction of prespore gene expression and multicellular development in Dictyostelium. In this manuscript, we further examine this regulatory role. We have overexpressed the Dictyostelium PKA catalytic subunit (PKAcat) in specific cell types during the multicellular stages, using prestalk and prespore cell-type-specific promoters to make PKA activity constitutive in these cells (independent of cAMP concentration). To examine the effects on cell-type differentiation, we cotransformed the PKAcat-expressing vectors with reporter constructs expressing lacZ from four cell-type-specific promoters: ecmA (specific for prestalk A cells); ecmB (specific for prestalk B and anterior-like cells in the slug); ecmB delta 89 (specific for stalk cells); and SP60 (prespore-cell-specific). By staining for beta-galactosidase expression histologically at various stages of development in individual strains, we were able to dissect the morphological changes in these strains, examine the spatial localization of the individual cell types, and understand the possible roles of PKA during multicellular development. Expression of PKAcat from either the ecmA or ecmB prestalk promoters resulted in abnormal development that arrested shortly after the mound stage, producing a mound with a round apical protrusion at the time of tip formation. Prestalk A and prestalk B cells were localized in the central region and the apical mound in the terminal differentiated aggregate, while prespore cells showed an aberrant spatial localization. Consistent with a developmental arrest, these mounds did not form either mature spores or stalk cells and very few cells expressed a stalk-cell-specific marker. Expression of PKAcat from the prespore promoter resulted in abnormal morphogenesis and accelerated spore cell differentiation. When cells were plated on agar, a fruiting body was formed with a very large basal region, containing predominantly spores, and a small, abnormal sorocarp. Mature spore cells were first detected by 14 hours, with maximal levels reached by 18–20 hours, in contrast to 24–26 hours in wild-type strains. When cells were plated on filters, they produced an elongated tip from a large basal region, which continued to elongate as a tubular structure and produce a ‘slug-like’ structure at the end. The slug was composed predominantly of prestalk cells with a few prespore cells restricted to the junction between the ‘slug’ and tube. As the slug migrated, these prespore cells were found in the tube, while new prespore cells appeared at the slug/tube junction, suggesting a continual differentiation of new prespore cells at the slug's posterior.(ABSTRACT TRUNCATED AT 400 WORDS)

Celiac sprue and diabetes mellitus

The frequent association of celiac sprue (CS) and insulin-dependent diabetes mellitus (DM) which may be the result of interplay between genetic, hormonal, and immunologic factors has obvious therapeutic implications. A gluten-free diet may improve the diarrhea in some patients with DM where the reason for diarrhea is underlying celiac sprue; the diet may also improve control of DM by normalizing the serum hormonal profile.

Molecular cloning of casein kinase II alpha subunit from Dictyostelium discoideum and its expression in the life cycle

A Dictyostelium discoideum cDNA encoding an alpha-type subunit of casein kinase II was isolated, and its cDNA was used to study developmental expression of casein kinase II during the Dictyostelium life cycle. The 1.3-kb cDNA insert contained an open reading frame of 337 amino acids (M(r) 39,900). The deduced amino acid sequence has high homology with those of casein kinase II alpha subunits from other species. Genomic Southern blot analysis suggested that there is a single gene encoding casein kinase II alpha subunit in D. discoideum. Northern (RNA) blot analysis showed that the casein kinase II alpha-subunit gene is expressed constitutively as a 1.9-kb mRNA throughout vegetative growth and multicellular development. Casein kinase purified from normal vegetative cells contained a major protein band of approximately 36 kDa, which was recognized by antisera raised against rat testis casein kinase II. Comparison of the in vitro transcription/translation product of the alpha-subunit cDNA clone and the purified 36-kDa protein by partial proteolysis indicated that the isolated cDNA clone encodes the Dictyostelium casein kinase II alpha subunit. No protein corresponding to a beta subunit was detected in purified casein kinase. Immunoblot analysis using anti-rat casein kinase II sera showed that the alpha subunit of casein kinase II is expressed constitutively like its mRNA during the life cycle of D. discoideum. Casein kinase II activity measured by using a specific peptide substrate paralleled the level of alpha subunit detected by immunoblotting during the life cycle, with a maximum variation of approximately 2-fold. We were unable to obtain disruptants of the casein kinase II alpha gene, suggesting that there is a single casein kinase II alpha gene, which is essential for vegetative growth of D. discoideum.

DdPK3, which plays essential roles during Dictyostelium development, encodes the catalytic subunit of cAMP-dependent protein kinase

We have previously reported the analysis of DdPK3, a developmentally regulated putative serine/threonine kinase that shares approximately 50% amino acid sequence identity with metazoan cAMP-dependent protein kinase A (PKA) and protein kinase C, within their catalytic domains. Cells in which the DdPK3 gene has been disrupted do not aggregate but they are able to induce aggregation-stage genes in response to cAMP pulses and the prestalk-specific ras gene DdrasD in response to high continuous levels of cAMP but will not induce prespore gene expression. In this report, we present conclusive evidence that DdPK3 encodes the catalytic subunit of the Dictyostelium PKA. DdPK3 null cells lack kinase activity that phosphorylates a PKA-specific substrate and is specifically inhibitable by recombinant cAMP-dependent protein kinase inhibitor. DdPK3 expressed in Escherichia coli has PKA activity that is inhibitable by protein kinase inhibitor. When Ddpk3 null cells are complemented with DdPK3 expressed from an actin promoter on an extrachromosomal vector (low copy number), PKA activity is restored and the cells proceed to the slug stage but will not culminate, suggesting that properly regulated PKA activity is essential for culmination. Moreover, overexpressing DdPK3 in wild-type cells on integrating vectors (high copy number) from either an actin or prespore-specific promoter results in accelerated development and the ability to form mature spores in monolayer culture in the presence of high cAMP, a developmental potential lacking in wild-type cells.

Effect of zinc sulfate and acetylcysteine on experimental gastric ulcer: in vitro study

A small ulcer produced in vitro by monopolar electrocoagulation on endoscopically obtained human antral biopsies and incubated in Trowel T-8 medium at 37 degrees C for 8 h has many histologic features of chronic gastric ulcer in man. Zinc sulfate and acetylcysteine in low concentrations had a significant healing effect in this ulcer model. Since the beneficial effect of zinc sulfate and acetylcysteine was counteracted by N-ethylmaleimide, a known blocker of sulfhydryl compounds, the beneficial effect of these two compounds probably was mediated through sulfhydryl compounds. Using special stain, N-(4-aminophenyl)maleimide, the sulfhydryl groups were localized in the epithelial cells of the surface layer and gastric glands.

A developmentally regulated, putative serine/threonine protein kinase is essential for development in Dictyostelium

Using PCR technology, we have cloned parts of three developmentally regulated putative serine/threonine kinases from Dictyostelium. All show significant homology to members of the cAMP-dependent protein kinase A/protein kinase C subfamilies. A genomic clone encoding one of these, DdPK3, has been isolated and sequenced. The open reading frame encodes a protein of 648 amino acids with the conserved kinase domain in the C-terminal half. The protein encoded by this gene is unusual in that it contains long homopolymer runs in the N-terminal half of the protein, including a long run of 88 amino acids in which 73 are glutamine residues. To examine the function of DdPK3, a gene disruption was created via homologous recombination. Ddpk3- cells do not aggregate by themselves but will co-aggregate with wild-type cells. However, after aggregation these cells are 'sloughed off' and do not proceed further through development, but are found as a discrete mass alongside the fruiting body formed by the wild-type cells. Analysis of signal transduction pathways indicates that cAMP pulse-induced expression of aggregation stage-specific genes is normal in Ddpk3- cells, as is induction of the prestalk gene Ddras in single cell assays. However, cAMP induction of the late promoters of cAMP receptor cAR1 and of two prespore-specific genes is absent under similar conditions. These cells show normal activation of adenylate cyclase and normal phosphorylation of the G alpha protein G alpha 2 in response to cAMP. The possible role of DdPK3 in Dictyostelium development is discussed.

Two-phase regulatory pathway controls cAMP receptor-mediated expression of early genes in Dictyostelium

Two classes of early genes in Dictyostelium are differentially regulated by extracellular pulses of cAMP interacting with its cell-surface receptor, conditions that also regulate chemotaxis and aggregation. The pulse-repressed genes, such as K5, are induced shortly after the onset of starvation and are repressed a few hr later during aggregation by cAMP pulses. The pulse-induced genes (including D2, M3, and those encoding contact sites A, the G alpha protein subunit G alpha 2, and the cell-surface cAMP receptor) are maximally induced just prior to aggregation by pulses of cAMP and are subsequently repressed by sustained moderate levels of cAMP--conditions that exist sequentially in development. In this manuscript, we further analyze the requirement for cAMP pulses and characterize a requirement for protein synthesis for the expression of these two classes of genes. Our results indicate that the control of expression of both the pulse-induced and pulse-repressed genes requires other developmentally regulated factors in addition to starvation and cAMP pulses. We also identified another early gene, F9, whose expression is stimulated upon starvation, is not responsive to cAMP, and is hyperstimulated by cycloheximide, in a manner similar to the cycloheximide stimulation of c-fos and other serum-induced genes in mammalian cells. Examination of the kinetics of expression of the pulse-induced genes in a mutant blocked in the cAMP relay pathway indicates that their expression is controlled by a two-phase process. The first phase requires starvation and CMF, an extracellular conditioned medium factor, and results in a low level of expression. The second phase requires establishment of the cAMP signal-relay system and induces the genes to a high level. Both phases require prior and concomitant protein synthesis. Some of the members of the pulse-induced class encode elements of the cAMP signal-relay system that controls aggregation, indicating a feedback autoregulation. The two-phase process might allow the "finetuning" of the level of expression of genes involved in aggregation.

Molecular analysis of a developmentally regulated gene required for Dictyostelium aggregation

We have previously shown that the developmentally regulated gene D2 is induced during aggregation by pulses of cAMP, which act via the cell surface receptor and consequent signal transduction pathways (W. Rowekamp and R.A. Firtel, 1980, Dev. Biol. 79, 409-418; S.K.O. Mann and R.A. Firtel, 1987, Mol. Cell. Biol. 7, 458-469; S.K.O. Mann, C. Pinko, and R.A. Firtel, 1988, Dev. Biol., in press). In this manuscript, we compare the complete derived amino acid sequence for D2 to two cloned and sequenced eukaryotic esterases and examine the requirement of the D2 gene product for development. Amino acid sequence data comparisons suggest that D2 encodes a serine esterase with strong sequence identity to Torpedo acetylcholine esterase and a Drosophila esterase. The protein has a putative leader sequence, suggesting that it is shunted into vesicles. Using an antisense gene construct driven by a Discoidin I promoter, whose transcriptional activity depends on the growth conditions of the cells, we show that inhibition of D2 mRNA accumulation results in an abnormal developmental program that includes the absence of normal streaming and incomplete aggregate formation and subsequent development. We suggest that D2 encodes an esterase function required for proper aggregation and subsequent development.

cAMP regulation of early gene expression in signal transduction mutants of Dictyostelium

We have examined the regulation of three early developmentally regulated genes in Dictyostelium. Two of these genes (D2 and M3) are induced by pulses of cAMP and the other (K5) is repressed. Expression of these genes has been examined in a number of developmental mutants that are specifically blocked in various aspects of the signal transduction/cAMP relay system involved in aggregation and control of early development. The mutant strains include Synag mutants, which are blocked in receptor-mediated activation of adenylate cyclase and do not relay cAMP pulses; FrigidA mutants, which are blocked in receptor-mediated activation of both adenylate cyclase and the putative phosphoinositol bisphosphate (PIP2) turnover pathway and appear to be mutations in the gene encoding one of the G alpha protein subunits; and a StreamerF allele, which lacks cGMP-specific cGMP phosphodiesterase. From the analysis of the developmental expression of these genes under a variety of conditions in these mutant strains, we have drawn a number of conclusions concerning the modes of regulation of these genes. Full induction of D2 and M3 genes requires cAMP interaction with the cell surface receptor and an "oscillation" of the receptor between active and adapted forms. Induction of these genes does not require activation of the signal transduction pathway that leads to adenylate cyclase activation and cAMP relay, but does require activation of other receptor-mediated intracellular signal transduction pathways, possibly that involving PIP2 turnover. Likewise, repression of the K5 gene requires pulses of cAMP. Expression of this gene is insensitive to cAMP pulses in FrigidA mutants, suggesting that a signal transduction pathway is necessary for its repression. Results using the StreamerF mutant suggest that the rise in cGMP in response to cAMP/receptor interactions may not be directly related to control of the pulse-induced genes. In addition, we have examined the effect of caffeine, which M. Brenner and S.D. Thomas (1984, Dev. Biol., 101, 136-146) showed preferentially blocks the cAMP relay system by blocking receptor-mediated activation of adenylate cyclase. We show that in many of the mutants and in an axenic wild-type strain, caffeine causes the induction of pulse-induced gene expression to almost wild-type levels or in some cases to higher than wild-type levels. Our data suggest that caffeine works by activating some step in the signal transduction pathway that must lie downstream from both the receptor and at least one of the G proteins and thus has effects other than simply blocking the receptor-mediated cAMP relay system.

Control of early gene expression in Dictyostelium

We have examined the expression of a cAMP pulse-repressed and two cAMP pulse-induced genes in response to cAMP and caffeine under a number of different physiological conditions, and in several classes of development mutants altered in cAMP-mediated signal transduction pathways. The data presented help characterize the mutants with regard to early gene expression. Analysis of the data indicates that full induction of the pulse-induced or repression of the pulse-repressed genes requires cycles of activation and adaptation of the cAMP receptor but does not require a rise in intracellular cAMP. Comparison of the results obtained between different mutant classes suggests that repression and activation of the two classes of genes can be uncoupled, implying that different intracellular mechanisms control these processes. In addition, we examined the effects of caffeine and show that it can induce pulse-induced mRNA accumulation in the absence of cAMP.

Cyclic AMP regulation of early gene expression in Dictyostelium discoideum: mediation via the cell surface cyclic AMP receptor

We examined two sets of genes expressed early in the developmental cycle of Dictyostelium discoideum that appear to be regulated by cyclic AMP (cAMP). The transcripts of both sets of genes were not detectable in vegetative cells. During normal development on filter pads, RNA complementary to these genes could be detected at about 2 h, peaked around 6 to 8 h, and decreased gradually thereafter. Expression of these genes upon starvation in shaking culture was stimulated by pulsing the cells with nanomolar levels of cAMP, a condition that mimics the in vivo pulsing during normal aggregation. Expression was inhibited by caffeine or by continuous levels of cAMP, a condition found later in development when in vivo expression of these genes decreased. The inhibition of caffeine could be overcome by pulsing cells with cAMP. These results suggest that the expression is mediated via the cell surface cAMP receptor, but does not require a rise in intracellular cAMP. mRNA from a gene of the second class was induced upon starvation, peaked by 2.5 h of development, and then declined. In contrast to the other genes, its expression was maintained by continuous levels of cAMP and repressed by cAMP pulses. These and other results on a number of classes of developmentally regulated genes indicates that changing levels of cAMP, acting via the cell surface cAMP receptor, are involved in controlling these groups of genes. We also examined the structure and partial sequence of the cAMP pulse-induced genes. The two tandemly duplicated M3 genes were almost continuously homologous over the sequenced portion of the protein-coding region except for a region near the N-terminal end. The two M3 genes had regions of homology in the 5' flanking sequence and showed slight homology to the same regions in gene D2, another cAMP pulse-induced gene. D2 showed extremely significant homology over its entire sequenced length to an acetylcholinesterase. The results presented here and by others suggest that expression of many early genes in D. discoideum is regulated via the cell surface cAMP receptor. We expect that many of these genes may play essential roles in early Dictyostelium development and could code for elements of the cAMP signal transduction pathway involved in aggregation.

Nasoenteral feeding tube insertion via fiberoptic endoscope for enteral hyperalimentation

Total parenteral nutrition can maintain good nutritional status in selected patients. However, it can be accompanied by serious complications. It is generally agreed that enteral alimentation is more economical and safer. Gut should be used for nutritional replenishment whenever feasible. However, large-bore nasogastric feeding tubes can cause problems. Even fine-bore nasogastric tubes can cause aspiration pneumonia in obtunded and debilitated patients. In some patients it is clearly desirable to have the tip of the feeding tube in the distal duodenum or proximal jejunum. Previously described methods for placement of nasoenteral tubes may be unsatisfactory. We describe a safe, simple, and reliable method for endoscopic insertion of fine-bore nasoenteral feeding tube. We have used this method on 15 patients without complication.

Infecundity and dominant lethal mutations induced in Musca domestica L. by sodium azide (NaN3)

Results of our study suggest that sodium azide is effective in the induction of sterility and dominant lethal mutations in both sexes of M. domestica L. When treated males were crossed with nontreated females, 100% dominant lethal mutations and 72.3% infecundity were found, whereas in the crosses of nontreated males and treated females, 82.5% dominant lethal mutations and 33.1% infecundity were found. This showed that males are more sensitive to sodium azide than females.

Fiberoptic colonoscopic study of experimental chemical colitis

Acute diffuse chemical colitis was produced in rats with a high degree of reproducibility by the intracolonic administration of 10% acetic acid. The evolution and progression of this colitis was followed by performing serial fiberoptic colonoscopy using a needlescope and biopsy. Hyperemia appeared at 10 hours and ulcerations appeared at 24 hours in acetic acid-treated animals. After 3 days, the ulcers were covered with a yellowish exudate. At 8 weeks there was endoscopic and histologic healing of the lesions. No changes occurred in the saline-treated animals. Concomitant topical applications of epsilon-aminocaproic acid protected against acetic acid-induced injury.

Effect of lactulose, neomycin and antacid on colonic pH recorded continuously with an implanted electrode

Colonic pH was continuously monitored by a pH electrode implanted in the transverse colon of rats over a 24-hour period. Lactulose significantly reduced the colonic pH to 5.37 +/- .39 from a fasting value of 6.77 +/- .75. Pretreatment with neomycin or concomitant use of a nonabsorbable antacid prevented lactulose-induced reduction in the colonic pH. The clinical implication of the study is that combined use of lactulose with neomycin or high doses of non-absorbable antacids in the treatment of chronic portasystemic encephalopathy may be undesirable.

Effect of monopolar electrocoagulation on esophagus, stomach and duodenum in dogs

The effects of electrocoagulation on the esophagus, stomach and duodenum of mongrel dogs were studied. A commercially available electrocoagulator unit and suction electrode were used. Various dial settings and duration times were used. The total number of sites electrocoagulated was 945; histologic section of each site was prepared. A dial setting of 7 and duration of 5 seconds was safe for the canine esophagus and duodenum; for the stomach it is a dial setting of 7 and duration of 3 seconds. This information will be useful in safe application of electrocoagulation to superficial bleeding lesions in the canine esophagus, stomach and duodenum.

Effect of chlorophyll-a, fluorouracil, and pituitrin on experimental acute pancreatitis

Intraductal administration of enterokinase in rats produced hyperamylasemia and acute hemorrhagic pancreatitis. The experimental pancreatitis and hyperamylasemia could be prevented by the concomitant intraductal injection of fluorouracil, pituitrin, or chlorophyll-a. The clinical implication of the study is that these agents, if given intraductally, may be useful in the prevention of iatrogenic hyperamylasemia and acute pancreatitis that may occur after endoscopic retrograde pancreatocholangiography.

Pancreatic Ascites

Ascites occurring in patients with a history of alcoholism is usually due to cirrhosis but clinically significant ascites also occurs in association with pancreatic disease. We reviewed 265 cases of pancreatitis over a five-year period. There were 129 blacks and 136 Caucasians. Ages ranged from 19-86 years with a mean of 46.2 years. Eight of these cases (3%) were found to have pancreatic ascites. The initial serum and urinary amylase had no prognostic value regarding the subsequent development of pancreatic ascites. The mean ascitic fluid amylase was 14,426 Somogyi units (range 1,279-67,774). The mean ascitic fluid protein was 4.6 gm./100ml. (range 1.4-7.2). High enzyme and protein concentration in the ascitic fluid are characteristic of pancreatic ascites. Out of eight cases, two were associated with a pseudocyst, three with hemorrhagic pancreatitis and three with acute edematous pancreatitis. Four of these eight (50%) died. Pancreatic ascites is a distinct clinical entity which should be differentiated from cirrhotic, tuberculous or malignant ascites.