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Biomedical subjects

J Dodge

Publications and source records attributed to J Dodge.

At least 37 records · Page 2Linked to original sources

Rhodopsin in immature rod outer segments.

PURPOSE: To test the hypothesis that rhodopsin concentration is low in immature rat rod outer segments (ROS). METHODS: Microspectrophotometry (MSP) was used to assess rhodopsin absorbances in localized regions of isolated ROS from dark-adapted 13-, 19-, and 34-day-old and adult rats. Photopigment was extracted from the retinas of paired eyes in dark-adapted and light-adapted rats. One retina of each pair was treated with 9-cis retinal before extraction of photopigment. Rhodopsin with native 11-cis retinal was extracted from the fellow retina. RESULTS: By MSP, rhodopsin absorbance was low in the short ROS of 13-day-old rats. In 19-day-old rats with ROS lengths approximately equal to those of adults, absorbance was low at the tip, but at the base, it was equal to the high absorbance at both the tip and the base in adults. The 9-cis retinal did not add absorbance to the photopigment extracts of dark-adapted retinas at any age, but it did add absorbance to extracts of the light-adapted retinas at every age. CONCLUSIONS: The MSP results show that the accumulation of rhodopsin in developing rat rods depends on increasing concentrations in localized regions. No evidence of apo-opsin is found in immature rat rods. Thus, in immature ROS regions, the low rhodopsin absorbances suggest that the amount of opsin is also low. Greater disk-to-disk spacing in immature ROS regions than in mature regions could account for these findings.

Aging↗

Morphological aspects of particle translocation in vivo following ingestion of the yeast Saccharomyces boulardii.

Particle translocation in vivo was studied in mice using the non-pathogenic yeast Saccharomyces boulardii (SB). Seven day old BALB/c mice were given either saline (control) or 1.5 g/Kg SB (every six hours, up to 48 hours), by intubation, and killed by decapitation 48 hours post-treatment. Light and scanning electron microscopy (SEM) examination of specimens prepared from the middle intestine revealed the presence of yeast inclusions localised in the cytoplasm of enterocytes.

Animals↗

Wortmannin, a potent and selective inhibitor of phosphatidylinositol-3-kinase.

Phosphatidylinositol-3-kinase is an important enzyme for intracellular signaling. The microbial product wortmannin and some of its analogues have been shown to be potent inhibitors of phosphatidylinositol-3-kinase. The 50% inhibitory concentration for inhibition by wortmannin is 2 to 4 nM. Kinetic analysis demonstrates that wortmannin is a noncompetitive, irreversible inhibitor of phosphatidylinositol-3-kinase, with inactivation being both time- and concentration-dependent. Wortmannin has previously been reported to be an inhibitor of myosin light chain kinase but with an inhibitory concentration of 0.2 microM. Wortmannin was found not to be an inhibitor of phosphatidylinositol-4-kinase, protein kinase C, or protein tyrosine kinase. Wortmannin inhibited the formation of phosphatidylinositol-3-phosphates in intact cells. The results of the study suggest that wortmannin and its analogues may have utility as pharmacological probes for studying the actions of phosphatidylinositol-3-kinase.

3T3 Cells↗

Chronic bullous disease of childhood and ulcerative colitis.

A 12-year-old girl with ulcerative colitis (UC) treated by colectomy with rectal stump preservation, salazopyrin, and systemic steroids developed persistent mouth ulcers, cutaneous targetlike lesions, papulopustules, and bullae. The clinical, histologic, and immunopathologic features were typical of chronic bullous disease of childhood (CBDC). Although resistant to combined immunosuppressive therapy with low-dose prednisolone, cyclosporin, and thalidomide, striking remission of the mucocutaneous symptoms resulted with surgical resection of the diseased rectal stump. An etiologic association between CBDC and UC is postulated.

Child↗

Role of hiatal hernia in delaying acid clearance.

The aim of this study was to assess prospectively the relationship of a hiatal hernia to gastro-oesophageal reflux. Ninety five children with symptoms of gastro-oesophageal reflux in whom reflux was demonstrated radiologically were investigated. Oesophageal pH monitoring for 18 hours and endoscopy were performed in all patients. On the basis of radiology, patients were divided into those with hiatal hernia (n = 37) and those without (n = 58). Both groups had the same number of reflux episodes on pH monitoring. However, the median duration of the longest episode was significantly greater in the hiatal hernia group (30 min v 19 min), as was the number of reflux episodes longer than five minutes (5 v 4). The percentage with a pH < 4 just failed to be significantly different (13% v 8%). Hiatal hernia was also found to correlate with the presence of oesophagitis. The presence of a hiatal hernia delays the clearance of acid from the oesophagus and is associated with an increased incidence of oesophagitis.

Adolescent↗

The quantity of rhodopsin in young human eyes.

The rhodopsin content of 20 eyes of infants and children ages 27 weeks gestation to 8 years (11 donors) was assayed and compared to the rhodopsin content of adults (36 eyes; 19 donors). Infants have significantly lower rhodopsin contents than adults. On average the rhodopsin content of young infants is about a third of adults. Previously reported full-field b-wave sensitivity of young infants is about 0.5 log units, that is about a third, less than adults. Thus, as previously found in infant rats, photon capture by rhodopsin appears to limit the dark adapted sensitivity of young human infants.

Adolescent↗

The quantity of rhodopsin in human eyes.

The content of rhodopsin in the eyes of 15 donors (30 eyes) was determined. Both retinal and pigment epithelial fractions were collected from each globe, extracted using 1% CTAB, and the rhodopsin difference spectrum of each fraction was obtained separately. The total amount of rhodopsin, obtained by summing the amounts recovered from the retinal and PE fractions, ranged from 2.00 to 11.94 (median: 6.40) nmoles/eye. Previously reported mean values of about 3.5 to 4.0 nmoles per retina have been obtained using a variety of methods. The present higher values, perhaps largely dependent on procedural details described herein, appear plausible given the known concentrations of rhodopsin in rod outer segments, rod outer segment volumes, and number of rods in the human retina.

Adult↗

Fatty acids in cystic fibrosis in response to a marathon race.

Lipid metabolism was studied in three cystic fibrosis (CF) patients (18 years old) and three healthy controls (35-40 years old) who completed the New York Marathon 1984. Lipase was not detectable in plasma from two of the CF patients, but in one CF patient with a functioning pancreas and in the three controls it increased during and after the run. Cholesterol concentrations were lower in all patients than in the controls. The HDL/total cholesterol ratios increased in all runners throughout the observation period, substantially more in the patients than in the controls. Triglycerides and glycerol values were similar in the two groups. The relative distribution of fatty acids in total plasma, plasma free fatty acid fractions, and total red blood cell membranes, at rest, were similar to those earlier reported both for the CF patients with pancreatic insufficiency and for the controls. Lower relative concentrations of linoleic acid (C18:2n6) and higher relative concentrations of C14:0, C16:0, C16:1, C18:3n6, and C20:3n6 were found in the CF specimens. During and after the race, linoleic acid concentration increased and the other fatty acids decreased, giving a more normalized pattern in the patients. The fatty acid pattern of the CF patient with a functioning pancreas behaved more like the healthy controls. The fatty acid pattern of the red cell membrane did not change during or after the run. Although the observations are few, it is encouraging that both the HDL/total cholesterol ratio and the fatty acid pattern improve in response to prolonged aerobic exercise.

Adolescent↗

Fecal incontinence in elderly patients.

Fecal incontinence is a common and important problem in the care of the elderly. An understanding of the defecation mechanism, appropriate differential diagnosis, and the best choice of treatment method are necessary to control this problem. Establishing a regular bowel program takes time and energy, but when the final result is continence, it is time and energy well spent.

Aged↗

Experience with ceftazidime in cystic fibrosis.

Twelve adults and children with cystic fibrosis received a total of 17 courses of ceftazidime for the treatment of an acute exacerbation of respiratory tract infection. In 6 cases ceftazidime was given as the sole antibiotic. All patients who were clinically assessable were considered to be cured of the acute infection, or improved. Bacteriologically all initial sputum specimens contained Pseudomonas aeruginosa. In 13 instances the organism disappeared during treatment, while in the other 4 the organism remained although the patients improved clinically. Additional organisms, usually Staphylococcus aureus or Haemophilus influenzae, were present in 7 instances. One patient suffered from nausea, palpitations and local skin inflammation on injection whilst being treated with ceftazidime, but the relationship between these adverse effects and ceftazidime was uncertain. The patient tolerated these effects without discontinuation of the drug.

Adolescent↗

Scalds to preschool children.

A survey of scalds to 64 children under five years of age was undertaken. The results showed that there was a wide variety of circumstances which resulted in these injuries. The significance of developmental aspects is demonstrated, as is the need to modify the child's environment. Poor supervision was not a significant factor in the incidents described. The problems associated with implementing various preventive strategies are discussed. It is concluded that more attention needs to be given to improving the effectiveness of "active" countermeasures due to the lack of practical "passive" countermeasures.

Beverages↗

A study of mothers' health.

The physical and mental health of the mothers of 991 children being examined in phase five of the Dunedin Multidisciplinary Child Development Study was assessed through two questionnaires which were designed to show changes in health status rather than to indicate defined disease. Less than one in five of the mothers gave no positive responses to the questionnaire on physical health and less than two in five gave no positive responses to the questionnaire on psychological health. The general level of health was lower than anticipated. Younger mothers showed more positive responses overall than older mothers and more frequent positive responses correlated significantly with family size and the presence of younger children in the family. It is considered that pressure of child rearing, especially in the larger families and in families with preschool aged children contribute to this lower health status.

Adult↗

Screening for cystic fibrosis by analysis of serum protein in faeces.

Faecal specimens from 51 infants free of cystic fibrosis (CF) and from 9 infants with the disease were analysed for albumin and alpha1-antitrypsin content. Faeces from infants with no CF had a mean albumin content of less than 0-1 mg/g dry weight and a mean albumin: alpha1-antitrypsin ratio value of less than 0-1. Faeces from infants with CF had, with one exception, an albumin content of more than 2-0 mg/g dry weight and a ratio value greater than 3-0. It was subsequently found that the duodenal aspirate from the child with CF but whose faeces had a low albumin content and ratio value, had tryptic activity though at a much reduced level compared to the activity in aspirates from healthy infants.

Albumins↗