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Biomedical subjects

S Davidson

Publications and source records attributed to S Davidson.

At least 127 records · Page 7Linked to original sources
PubMed1989

Safety and efficacy of three oral rehydration solutions for children with diarrhoea (Edinburgh 1984-85).

Of 357 children with acute diarrhoea admitted to the City Hospital, Edinburgh, over a 12-month period, only 5 (1.4%) required IV infusions. Three hundred and nineteen were treated with oral rehydration (OR). Of these 269 were studied in detail and 43% had signs of dehydration, but in none of them was it severe. There were no fatalities. Patients were randomly allocated to treatment with one of three OR solutions in a double blind trial. The solutions had sodium concentrations of 35, 50 and 90 mmol (mEq)/l, and dextrose of 200 (36 g/l), 111 (20 g/l) and 110 (19.8 g/l) mmol/l, respectively. Hypernatraemia was not a clinical problem and only 5 children (2%) were biochemically hypernatraemic on admission. Treatment did not cause clinical hypernatraemia. At the second assessment only 3 children were biochemically hypernatraemic, one from each treatment group, and no one had clinical signs. All three solutions were safe and effective in the relatively mildly dehydrated patients currently seen in the UK.

Child↗
PubMed1988

Stimulus-response coupling in marine sponge cell aggregation: lipid metabolism and the function of exogenously added arachidonic and docosahexaenoic acids.

Cells of the marine sponge, Microciona prolifera, the most ancient of the animal cells which clump on recognition, resemble neutrophils and platelets in undergoing stimulus-response coupling when exposed to Ca2+ ionophores and phorbol esters. We have studied lipid content and remodelling in sponge cells by thin-layer, gas-liquid, and high-performance liquid chromatography (HPLC) analyses supplemented by ultraviolet and mass spectroscopy. Phosphatidylcholine (PC) (35.6%), phosphatidylethanolamine (PE) (27.4%) and phosphatidylserine (PS) (21.4%) constituted the bulk of phospholipids detected. The major fatty acids were all polyenoic; 22:6 (22%), 26:2 (17%) and 26:3 (15%). Arachidonic acid (20:4), present as 2.7% of total phospholipid, and docosahexanoic acid (22:6) were found to elicit aggregation of sponge cells when added (10 microM) in synergy with ionomycin (1 microM), resembling in their effects those of phorbol esters (but not phorbol) and 1-oleyl-2-acetylglycerol (OAG). Moreover, 20:4 and 22:6, as well as phorbol ester and OAG, overcame the block to aggregation imposed by colchicine and vinblastine. Kinetic studies of lipid remodelling showed that aggregating cells diverted [14C]22:6 or [14C]20:4 from triacylglycerol into diacylglycerol and phospholipids; appearance of label in phosphatidic acid and phosphatidylinositol (PI) anteceded labeling of phosphatidylcholine. In unstimulated cells, [14C]22:6 was rapidly incorporated into phosphatidylcholine with little accumulation in phosphatidate. Although 22:6 and 20:4 resembled OAG and phorbol esters in overcoming the effects of colchicine and vinblastine (which had no effects on overall lipid metabolism), they did not reverse the block to aggregation of nordihydroguaiaretic acid (NDGA) (which inhibited lipid metabolism). Under none of these circumstances was 22:6 or 20:4 converted to cyclooxygenase or lipoxygenase products in the course of aggregation: all labeled acyl groups remained present as unmodified fatty acids on alkaline hydrolysis. These data not only extend the observations of Muller et al. (J. Biol. Chem. 262 (1987) 9850-9858) on the role of phosphoinositides and C kinase in marine sponge cell aggregation, but also demonstrate that sponges form diacylglycerols in the process. We suggest that exogenous 22:6 and 20:4 (like phorbol esters or OAG) can substitute for endogenous diacylglycerol in the activation of protein kinase C.

Animals↗
PubMed1988

Mapping from GenBank to MEDLINE.

GenBank has been based largely on literature that provides nucleic acid sequences. To find additional literature that is relevant to a given sequence, a search of MEDLINE can prove helpful. This paper documents some of the similarities between GenBank and MEDLINE that facilitate retrieval of documents from MEDLINE. In particular, techniques and examples are presented which take GenBank information and lead to MEDLINE information that supplements the GenBank information.

Abstracting and Indexing↗
PubMed1988

Tendon transfers for ulnar nerve palsy. Evaluation of results and practical treatment considerations.

Tendon transfers for correction of clawing deformity in ulnar nerve palsy are only consistently successful in young ligamentously lax individuals. Correction of deformity is most inconsistent in the intrinsically stiff hands of older individuals. Correction of clawing is more difficult in the little finger than in the ring finger. While use of the flexor digitorum superficialis for intrinsic transfer simply corrects clawing deformity and restores synchronous finger flexion, grip strength will be further decreased by approximately 21 percent, and total active range of motion by 7 percent. Correction is best achieved by transfer of a wrist motor with tendon graft into index, middle, ring, and little digits, despite limitation of clawing to the ring and little digits. Pinch should be augmented by metacarpophalangeal joint fusion rather than by interphalangeal joint fusion. When combined with extensor carpi radialis brevis adductor plasty, pinch strength can be doubled.

Hand↗
PubMed1987

Ciprofloxacin therapy in cystic fibrosis.

There is great need for an oral agent that could be used to treat pulmonary exacerbations in patients with cystic fibrosis. In this study, the use of oral ciprofloxacin as sole therapy was evaluated in 18 patients with 39 infectious episodes; 13 episodes were classified as severe, 19 were classified as moderate, and seven were classified as mild. Patients ranged in age from eight to 36 years (mean, 23 years). Dosage varied according to severity of disease, body size, and the susceptibility of the Pseudomonas isolate to ciprofloxacin; the dose ranged from 750 to 2,250 mg daily (mean, 1,800 mg). Ten patients received one course of ciprofloxacin, and eight received repeated courses. The overall clinical response rate was 82 percent. There was a response to the initial treatment course in 96 percent of the patients. Those in whom therapy failed had been re-treated with ciprofloxacin and were severely ill. Failure to respond correlated poorly with pretreatment minimal inhibitory concentration (MIC) values (0.6 microgram/ml for failures versus 0.4 microgram/ml for responses). Pseudomonas could not be eradicated from the sputum of any of the patients, although there was a marked reduction in purulence and bacterial counts. In general, patients who did not require re-treatment for three months would again have susceptible organisms. When organisms became resistant to ciprofloxacin (MIC greater than 2 micrograms/ml), they showed no concomitant new aminoglycoside or beta-lactam resistance. No serious toxicity occurred in any of the 39 episodes of treatment. In seven patients treated with combination therapy (tobramycin or azlocillin), the infecting organisms were reduced in number, but eradication of Pseudomonas generally could not be achieved. Increases in MIC occurred during combination therapy. Ciprofloxacin is a major advance in the treatment of bronchopulmonary infection in patients with cystic fibrosis.

Adolescent↗
PubMed1987

Cardiorespiratory depression and plasma beta-endorphin levels in low-birth-weight infants during the first day of life.

Twenty-nine premature infants were studied to determine whether neonatal asphyxia, apnea, and low blood pressure in the first day of life are associated with elevated plasma beta-endorphin concentrations. Plasma beta-endorphin levels were determined at 0.5 to 2, 4 to 6, and 18 to 24 hours of life, using radioimmunoassay. Premature infants with moderate or severe asphyxia (n = 19) had higher levels at 0.5 to 2 hours of age (32.1 +/- 6.7 vs 16.4 +/- 7.4 pmol/L) and significantly higher levels at 4 to 6 hours of age (50.4 +/- 10.0 vs 22.9 +/- 9.2 pmol/L) compared with the ten nonasphyxiated premature infants. A significant elevation in levels at age 0.5 to 2 hours (39.4 +/- 9.9 vs 17.7 +/- 4.4 pmol/L) and age 4 to 6 hours (59.3 +/- 13.8 vs 27.1 +/- 17.1 pmol/L) was observed in premature infants with low blood pressure or impaired perfusion (n = 12) who required the administration of volume expanders. No differences were observed in premature infants with and without apnea. It may be speculated that the increased endogenous release of beta-endorphins in response to perinatal asphyxia may play a role in the pathogenesis of shock observed in the first day of life.

Apnea↗
PubMed1987

Purification of polypeptide growth factors from milk.

There appear to be at least three growth factors for mouse BALB/c 3T3 cells in human milk. The purification of the predominant one is described in this chapter. Biochemical and immunological studies indicate that this growth factor is probably a form of human epidermal growth factor (EGF). Like EGF, the major human milk-derived growth factor has a molecular weight of about 6000, a pI of about 4.5, and is resistant to inactivation by dithiothreitol. (See this volume, Harper et al., for purification of human EGF.) In addition, Carpenter has shown that antibodies against human EGF will precipitate most of the growth factor activity for 3T3 cells found in human milk. The EGF-like species of growth factor cannot be detected in bovine milk. Instead, the major growth factor in bovine colostrum appears to be biochemically similar to platelet-derived growth factor (PDGF). Like PDGF, the bovine colostrum-derived growth factor has a molecular weight of about 30,000, a pI of about 10, is totally inactivated by dithiothreitol but is stable to treatments with guanidine-HCl, urea, and heat. Biochemical characterizations of milk-derived growth factors, EGF, and PDGF are summarized in Table III. At present, very little is known about the physiological role of these growth factors in milk. The availability of these growth factors in homogeneous form will facilitate the studies in understanding their possible involvement in the growth process.

Animals↗
PubMed1987

Intussusception in a premature infant simulating necrotising enterocolitis.

Intussusception in older infants is manifested by bloody stools, colicky abdominal pain and a palpable abdominal mass. In neonates the symptoms are often restricted to vomiting, guaiac positive stools and abdominal distension. These symptoms closely mimic necrotising enterocolitis. Surgical treatment of necrotising enterocolitis should be postponed until perforation of the gastrointestinal tract has occurred, whereas, prompt surgical treatment is recommended for intussusception. We report a case of intussusception that simulated necrotising enterocolitis in a 740 grammes premature infant in the second week of life. The clinical and radiographic features are described and the difficulty in distinction between the two conditions is emphasised. Neonatologists and paediatric surgeons should always include intussusception in the differential diagnosis of abdominal distension and guaiac positive stools in small premature infants.

Diagnosis, Differential↗
PubMed1987

Multiple forms of basic fibroblast growth factor: amino-terminal cleavages by tumor cell- and brain cell-derived acid proteinases.

Basic fibroblast growth factor (FGF) was purified by heparin-Sepharose chromatography from two sources, brain and hepatoma cells. Brain cell-derived basic FGF (brFGF) and hepatoma cell-derived basic FGF (heFGF) were found to exist in multiple forms whose molecular weights depended on whether they were extracted from their respective tissue or cells at neutral or acid pH. When extracted at pH 7.0 brFGF and heFGF comigrated on NaDodSO4/PAGE with a Mr of approximately 18,400. When extracted at pHs 3.5-4.5, acid proteinases cleaved brFGF and heFGF to lower molecular weight forms but to different extents. brFGF was cleaved to a Mr 18,000 form at acid pH by a brain-derived acid proteinase that could be inhibited by pepstatin. heFGF was cleaved mostly to a Mr 16,500 form at acid pH by a hepatoma cell-derived acid proteinase that was inhibited by leupeptin. Electrophoretic transfer blot analysis using site-specific anti-FGF antibodies suggested that the cleavages occurred at the amino-terminal ends of brFGF and heFGF. Cleavage to lower molecular weight forms of brFGF and heFGF did not affect growth factor activity or chromatographic behavior on heparin-Sepharose columns.

Amino Acid Sequence↗
PubMed1987

Trisomy 13 in monozygotic twins discordant for major congenital anomalies.

The occurrence of trisomy 13 in twins is very rare. We report a pair of genotypically identical twins with trisomy 13 discordant for major anomalies. This case contributes to the already published data on the contribution of non-genetic factors to the aetiology of congenital malformations in monozygotic twins.

Abnormalities, Multiple↗
PubMed1987

Searching for patterns in the MeSH vocabulary.

NLM revises its MeSH vocabulary annually to reflect changes in biomedical literature and the health sciences community. This study tested two hypotheses about NLM's MeSH vocabulary. The first is that new terms are added to MeSH when their broader terms have an increased number of postings. One examination compared the number of postings for the broader terms of new and existing terms in the current MEDLINE file; the other compared them over time. No significant statistical difference was found in either case. A second hypothesis--that there is a relationship between the patterns of MEDLINE indexing and searching and the organization of the MeSH tree structure--was tested by comparing the distribution of searched terms in the MeSH trees with the distribution of all terms. It was found that certain trees are searched more often than could be predicted by the overall term distribution, while others are searched less frequently than expected. In summary, (1) new terms cannot be predicted by the increase in postings of existing terms, and (2) searchers' and indexers' use of the terms' tree structure does not correlate with the terms' distribution in the MeSH trees.

Abstracting and Indexing↗
PubMed1986

Group excellence: a model for the application of Japanese management to mental health centers.

Mental health centers and other government sponsored service organizations need highly effective management techniques. In this era of tightening budgets, the Japanese Management System may be a way of increasing both excellence and employee satisfaction. Managers who choose to explore this system may need a concise, written model as a guide to the ingenious, extensive, and paradoxical Japanese Management System. The System centers around quality control circles--autonomous problem-solving groups that strive for excellence. Composed of hierarchically interlocking groups, it uses a wide selection of group cohesion techniques to inspire esprit de corps, and an interlocking set of rewards governs behavior at every level. Decision making is collective (although supervisors retain veto power), and execution of ideas, once agreed upon, is quick and consistent. The System operates holistically, enthusiastically, with a high degree of excellence and mutual concern.

Community Mental Health Centers↗