Protein-sparing diet for severely obese adolescents: design and use of an equivalency system for menu planning

When severe, obesity in adolescence demands effective treatment, thus justifying use of a protein-sparing, low-energy diet for periods of 3 to 4 months. When properly planned and supervised, this diet is safe and effective, even if only to maintain a functional body weight. The regimen used at the Hospital for Sick Children, Toronto, provides 2.0 to 2.5 gm protein per kilogram ideal body weight, plus adequate fluid and nutrient supplements. The amounts of meat, poultry, and fish that supply this allocation of protein are determined using a protein equivalency system developed for the diet. The system allows both dietitians and patients to plan meals that minimize energy intake while maintaining protein adequacy and dietary variety. With prolonged use of the diet, limited carbohydrate may be added in the form of selected vegetables measured using a similar carbohydrate equivalency system. Recent use of the diet for 21 patients, 8 to 20 1/2 years old and averaging 211% ideal body weight, resulted in acceptable weight control.

An ultrastructural study of meconium corpuscles in human foetal colon

In human foetal colon meconium corpuscles were observed in the colonic epithelium during the stage of secondary lumina development and enlargement. Transmission electron microscopy of these specimens revealed inclusion bodies in the superficial and deeper layers of the epithelium. Many of the membrane-bounded inclusion bodies contained well-preserved organelles and some inclusions contained nuclear fragments. There was evidence of nuclear fragmentation with condensed chromatin arranged in crescentic caps. The ultrastructural observations are typical of apoptosis, a mode of cell death first described in 1972 by Kerr and colleagues. Thus, meconium corpuscles are apoptotic bodies found as a result of the deletion of healthy normal cells during the reshaping and development of organs.

Use of information technology by clinical dietitians in Canada

Information technology in health care in Canada is beginning to show an impact in clinical dietetics. Good response (64%) to a survey of 307 hospitals indicated that 15 hospitals now use computers for the assessment of nutrients in patients' food intakes, in menus, and in recipes. Another 76 plan to initiate computer use. The majority of nutrition and food service departments categorize computers as potentially 'very useful' in clinical dietetics. The 15 respondents who use computers serve as models for future users. Hand calculation of nutrients is performed to some degree by 170 hospitals. Information from these respondents indicated that they share many common needs, thus encouraging a cooperation of effort in future computer applications.

General practice audit of asthma in childhood

It has been suggested that asthma is underdiagnosed in children. We studied the records of 52 children with asthma in our group practice. Although asthma had been positively diagnosed in roughly 10% of the children aged 18 months to 11 years, to make the diagnosis required an average of 16 to 20 consultations for respiratory problems. According to the symptoms recorded before the diagnosis was made, only three quarters of the children had presented with wheeze and roughly a third had had difficulty in sleeping. We think that the doctor's time would be better spent teaching patients about their asthma than by repeatedly treating non-existent respiratory infection.

Expression in Bacillus subtilis of the gene for human urogastrone using synthetic ribosome binding sites

A chemically synthesised gene coding for human urogastrone which was earlier cloned in E. coli (Smith et al. 1982) has now been cloned into expression vectors for Bacillus subtilis. Two types of constructs have been made, one giving production of methionyl-urogastrone and the other giving rise to a methionyl-urogastrone-beta galactosidase fusion polypeptide facilitating quantification of expression levels. The ribosome binding sites used in the expression plasmids are synthetically made oligonucleotides residing on short restriction fragments to allow easy replacement by other ribosome binding sites. Using "shuttle" vectors and constitutive promoters from Bacillus phages phi 105 and SPP1, we were able to detect levels of expression amounting to a few thousand molecules per cell during logarithmic growth in both E. coli and B. subtilis.

An ultrastructural study on the "meconium corpuscles" in rat foetal intestinal epithelium with particular reference to apoptosis

During the embryonic development of the intestine, programmed deletion of epithelial cells plays a vital role in the formation of secondary lumina and of villi. Electron microscopy shows that this deletion is effected by apoptosis, a distinctive mode of cellular death recently recognised as being implicated in normal tissue involution in the adult, as well as during intrauterine development. The process involves cellular condensation and budding to form membrane-bounded apoptotic bodies containing well-preserved organelles. These are then either engulfed by neighbouring principal cells or sloughed off into the intestinal lumen. Engulfed apoptotic bodies that show various degrees of lysosomal degradation have previously been referred to as "meconium corpuscles".

Early gastric cancer in a United States hospital

Early gastric cancer (EGC) confined to mucosa and submucosa, described by Japanese physicians over 20 years ago, yields about 90% 5-year postoperative survival. EGC has been increasingly reported from centers outside Japan, but rarely from the United States. Between 1976-1981, EGC was found in six patients or about 8.5% of all gastric carcinomas diagnosed in our hospital. Diagnoses were established by following suspicious upper gastrointestinal series or negative x-rays in patients with dyspepsia by means of gastroscopy and gastroscopically obtained biopsies, brush, and/or wash cytology. All six patients underwent subtotal gastrectomy with histological findings of EGC not invading the muscularis and with no metastases. So far no tumor recurrences have been found in these six patients. The results suggest that EGC as defined by Japanese investigators occurs in our hospital and presumably across the United States more often than heretofore appreciated. Previous fatalistic attitudes toward diagnosing gastric cancer should be replaced by efforts at early diagnosis. Patients with symptoms suggestive of gastric carcinoma, including unexplained dyspepsia, should undergo early upper gastrointestinal x-ray and endoscopic examinations with biopsies and cytological tests of any suspicious raised, flat, or depressed area.

Cloning and expression of a porcine prorelaxin gene in E. coli

A porcine prorelaxin gene has been constructed partly by synthetic means and partly from its natural messenger RNA. A gene coding for the 32 N-terminal amino acids including a chain initiator methionine codon (B gene) was synthesised and inserted in a plasmid at a site downstream from a tryptophan promoter in such a way that its expression is under the control of the trp promoter. DNA corresponding to the rest of the prorelaxin was prepared using reverse transcriptase extension of a primer complementary to relaxin mRNA and joined at a suitable restriction site to the B gene. Transformation of E. coli with this plasmid followed by suitable induction resulted in the synthesis of a new protein identified as prorelaxin by its size and its antigenic similarity to relaxin.

Separation of branched from linear DNA by two-dimensional gel electrophoresis

A general method for separating branched DNA molecules, such as replication forks and recombination intermediates, from linear forms has been developed. Using as a model a stable X-shaped molecule constructed in vitro, it was found that this branched form migrated more slowly during agarose gel electrophoresis than did a linear form of the same mass. Higher agarose concentrations and higher electrophoretic voltages enhanced the extent of retardation. These properties provided the basis for an electrophoretic method of separating branched from linear molecules by variation of agarose concentration and voltage over two dimensions. In the first dimension, concentration and voltage were low; in the second, both parameters were increased, thereby forcing X-shaped molecules to migrate to positions distinct from a diagonal arc of linear molecules. In addition, two-dimensional electrophoresis was capable of separating X-shaped forms of different mass from each other, as well as from linear molecules.

A scanning and transmission electron microscopical study of the morphogenesis of human colonic villi

The morphogenetic events that occur in the development of villi in human foetal colon have been observed by light microscopy and scanning and transmission electron microscopy. At nine weeks, the colon is a simple tube composed of pseudostratified columnar epithelium and mesenchyme. By ten weeks, up to eight longitudinal ridges have formed by an elongation of individual epithelial cells. Even as the ridges are forming, the bases of some of the ridges become indented with mesenchyme thus forming longitudinal mucosal folds. By eleven and a half weeks, these have folded in a concertina fashion forming a longitudinal zig-zag pattern. From ten and a half weeks, small lumina develop within the epithelium near to its base. At this stage, they are not in continuity with the main lumen. Extension of these lumina to the main luminal surface and exfoliation of redundant cells result in division of the zig-zag folds into broad primary villi. Division of the primary villi occurs when cyst-like structures which develop within the pseudostratified columnar epithelium of the primary villi enlarge and extend to the lumen. Together with upgrowth of mesenchyme this results in small secondary villi with simple columnar epithelium.

The molecular cloning and characterisation of cDNA coding for the alpha subunit of the acetylcholine receptor

A rare cDNA coding for most of the alpha subunit of the Torpedo nicotinic acetylcholine receptor has been cloned into bacteria. The use of a mismatched oligonucleotide primer of reverse transcriptase facilitated the design of an efficient, specific probe for recombinant bacteria. DNA sequence analysis has enabled the elucidation of a large part of the polypeptide primary sequence which is discussed in relation to its acetylcholine binding activity and the location of receptor within the plasma membrane. When used as a radioactive probe, the cloned cDNA binds specifically to a single Torpedo mRNA species of about 2350 nucleotides in length but fails to show significant cross-hybridisation with alpha subunit mRNA extracted from cat muscle.

Revision of the Ontario phenylalanine equivalency system and development of a low protein equivalency system

The Phenylalanine Content of Foods, an equivalency system used in the dietary treatment of phenylketonuria, was prepared in 1975. Recently this system was revised to include a total of 372 food items in various raw and processed states. Food lists are available in a simple version for parents listing the serving size per phenylalanine equivalent, and in a more comprehensive version for dietitians providing weights for the serving sizes as well as values for phenylalanine, protein, and energy per equivalent. Subsequently, the system was modified to form a low protein equivalency system for use in designing low protein diets for a number of other inherited metabolic disorders.

Use and design of low protein diets for children with inborn metabolic disorders

Low protein diets are used to treat infants and children with hyperammonemia due to urea cycle and other metabolic disorders as well as a number of amino and organic acidopathies. The incidence of these disorders is small and many are life-threatening. As a result, there is little in the literature on the dietary management of these patients. This paper draws on 10 years of clinical experience at the Hospital for Sick Children in Toronto, Ontario and presents a guide to the preparation of infant formulas providing levels of protein intake from 0.5 to 2.0 g per kg. Also described is a low protein equivalency system that is a useful guide for measuring both baby foods and table foods for affected children up to about six years of age. This dietary information is accompanied by a description of the disorders amenable to low protein diets, some of the adjunctive therapies employed and the nutritional concerns associated with severe restriction of protein.

Hyperornithinaemia and gyrate atrophy of the retina: improvement of vision during treatment with a low-arginine diet

A 15-year-old patient with hyperornithinaemia (0.6--1.2 mmol/l) and gyrate atrophy of the retina was given a low-arginine diet to reduce plasma ornithine to a concentration (0.15--0.25 mmol/l) near the normal range. After five weeks of treatment, there was improvement in the visual function of one eye which had been severely impaired without improvement for 3 years. This improved visual function was maintained until compliance with the diet deteriorated at eight months, after which visual function regressed towards pretreatment status. Overrestriction of dietary arginine produced hyperammonaemia, indicating that arginine is an essential aminoacid in ornithine transaminase deficiency. These results suggest that reduction of plasma ornithine may reverse a metabolic neuroretinopathy in this disease, and offer hope that progression of the retinal atrophy can be arrested as well.

Effect of cimetidine and sodium bicarbonate on pancreatic replacement therapy in cystic fibrosis

Fifteen patients with cystic fibrosis and pancreatic insufficiency were studied during four randomised seven day treatment periods in which they received only pancreatic supplement (Pancrelipase, 27 capsules per day) or supplement plus cimetidine (20 mg/kg body weight/24 h) or sodium bicarbonate (15 g/m2/24 h) alone or in combination. Dietary intake was not fixed but was restricted to foods of known fat and nitrogen content from which daily intakes could be computed. Faecal fat and nitrogen were calculated as g/24 h and percentage of intake. Addition of either cimetidine or bicarbonate resulted in significant improvement in fat and nitrogen excretion, which was not greater with the combination of both drugs. Cimetidine and sodium bicarbonate in these doses are therefore sufficient to produce maximal improvement in digestive activity of pancreatic supplements. Fat excretion per gram of intake fell with cimetidine and bicarbonate from 12 times the normal level, to normal, in patients consuming less than 120 g fat daily. Above this intake the dose of pancreatic supplement appeared to be inadequate. Faecal nitrogen excretion increased with nitrogen intake in all four periods, but, in contrast with fat excretion, the response to cimetidine and bicarbonate was not affected by the level of intake. Dietary intake appears to be a significant factor in determining the faecal output of fat and nitrogen in patients with pancreatic insufficiency and should be considered when determining the optimum amount of pancreatic supplementation.

Treatment of gyrate atrophy of the choroid and retina with low arginine diet

In gyrate atrophy the blood ornithine is grossly elevated, due to deficiency of ornithine ketoacid transaminase, which converts ornithine towards glutamic acid. Two patients with gyrate atrophy have been treated with a low arginine diet and their blood ornithine levels have been reduced to near normal. At this level hyperammonemia may result from overtreatment, but this can be quickly cleared by a small dose of arginine. There has also been some improvement in vision, but no clearing of the gyrate areas. Future care with this regimen seems possible and improvements in handling of these patients are likely.

Leptospirosis in meat inspectors: preliminary results of a serological survey

A serological survey of leptospirosis among more than 1000 meat inspectors, from meat works throughout New Zealand, revealed a serological prevalence at a minimum serum dilution of 1:24, of 10.2 percent. Eighty-five percent of serological reactions were to serovars pomona and tarassovi. A highly significant correlation was demonstrated between the serological prevalence of these serovars and the inspection of pigs. Evidence is provided to substantiate the use of titres as low as 1:24 as an indication of previous leptospiral infection. Forty-two inspectors reported medical evidence of previous clinical infection with leptospirosis. Analysis of those who still exhibited a serological response and their individual case histories, indicated that detectable titres of leptospirosis can exist for up to 10 years.

Occurrence of crossed strand-exchange forms in yeast DNA during meiosis

The crossed strand-exchange form (Holliday structure, half chiasma) has been predicted as an intermediate in the genetic recombination of eukaryotes. We report here the detection of this form in the yeast plasmid, 2-micron DNA, isolated during meiosis. Physical mapping has previously suggested that two forms of 2-micron DNA arise because of recombination between inverted repeat regions. After appropriate digestion with restriction endonuclease, a crossed strand-exchange form intermediate in this recombination would yield an X-shaped form resistant to loss by branch migration because of nonhomology in sequences flanking the region of homology. We first generated this X-shaped form artificially by reannealing melted restriction fragments of 2-micron DNA. This enabled us to develop a procedure for the physical separation of the X-shaped form by agarose gel electrophoresis. We then used this electrophoretic procedure to isolate a naturally occurring form of identical structure from the 2-micron DNA of meiotic cells. Electron microscopy demonstrated that the exchange junction had the expected configuration of strands and indicated that the junction occurred within the region of homology.