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Biomedical subjects

M Dalton

Publications and source records attributed to M Dalton.

At least 55 records · Page 3Linked to original sources
PubMed1993

Serine 1002 is a site of in vivo and in vitro phosphorylation of the epidermal growth factor receptor.

We have shown previously that treatment of A431 cells with epidermal growth factor (EGF) induces desensitization of the EGF receptor. We now show that this desensitization is associated with an increase in the phosphorylation of the receptor on Ser-1002. Using a synthetic peptide corresponding to the sequence surrounding Ser-1002, p34cdc2 was identified as a kinase capable of phosphorylating this serine residue. Purified Xenopus p34cdc2 was found to phosphorylate the synthetic peptide on the serine residue corresponding to Ser-1002. This kinase also phosphorylated purified EGF receptor in vitro on Ser-1002. Phosphorylation of the EGF receptor by p34cdc2 was associated with a decrease in its tyrosine protein kinase activity. These data indicate that the EGF receptor may be a target for phosphorylation by a cyclin-dependent kinase in vivo and imply that receptor function may be regulated in a cell cycle-dependent fashion.

Amino Acid Sequence↗
PubMed1993

Recurrence of unexpected infant death.

Families which had experienced two or more unexpected infant deaths were the subject of detailed confidential enquiries, including necropsy examination. Cases were derived from two main sources: first, deaths occurring during a nationwide programme of support for families with a subsequent baby (8 families) plus 2 families from a series of confidential enquiries in Sheffield, and second, direct referrals from paediatricians (17 families). Fifty-seven deaths were studied. Twenty-four families had experienced 2 and three had experienced 3 deaths; 11 deaths (19%) were found to be adequately explained by history or post-mortem findings; 7 (12%) were probably accidental; 31 (55%) were most probably due to an action by one of the parents (filicide); only 5 (9%) were considered to be true or idiopathic sudden infant death syndrome; in 3 (5%) cases there was insufficient information to draw a conclusion. Five (18%) of the families lived in circumstances of serious social deprivation. A history of psychiatric illness was present in one or both parents in 18 (67%) of the families.

Age Distribution↗
PubMed1992

Prevalence of asthma in regional Victorian schoolchildren.

OBJECTIVE: To determine whether the high prevalence of reported asthma in Melbourne schoolchildren is seen in rural Victoria. DESIGN: A questionnaire on respiratory symptoms was distributed to children to be completed by parents and returned to the school. Results were compared with a previous Melbourne study. SETTING: Two hundred and twenty-seven government and non-government primary schools in five rural regions of Victoria: coast, wheatbelt, riverland, highland and Latrobe valley. SUBJECTS: All children enrolled in grade 2 were invited to join the study. Parents completed questionnaires for 4661 children after 4886 questionnaires were distributed (response rate, 95%). MAIN OUTCOME MEASURE: History of wheeze in the past 12 months. RESULTS: The overall prevalence of wheeze in the last 12 months was 23.6%. There was a significant difference overall in this rate across the five rural areas and Melbourne, with the Latrobe Valley (26.2%) and highland areas (25.0%) having the highest rate, and the wheatbelt the lowest (19.6%). The spectrum of severity of asthma was similarly distributed across rural regions, although severe episodes were significantly more frequently reported by parents from rural areas than by parents in Melbourne. The reported use of bronchodilators and diagnosis of asthma showed a similar pattern of variation to that of the 12-month prevalence of wheeze. CONCLUSION: The prevalence of asthma in 7-year-old children is similar for rural Victoria as a whole compared with Melbourne, but there is variability in asthma prevalence in individual rural areas which is difficult to account for in terms of known environmental precipitants.

Asthma↗
PubMed1992

A therapeutic trial of the use of penicillin V or erythromycin with or without rifampin in the treatment of psoriasis.

BACKGROUND: After the publication of an uncontrolled trial of nine patients with streptococcus-associated psoriasis who appeared to benefit from a course of oral penicillin or erythromycin with the addition of rifampin in the last 5 days, we wished to confirm or refute the validity of this observation. OBJECTIVE: Our purpose was to confirm the effectiveness of antibiotics in the treatment of streptococcus-associated psoriasis. METHODS: Twenty patients were placed randomly into two groups. One group was given penicillin or erythromycin for 14 days with a placebo added during the last 5 of the 14 days. The other group received the same medication with the addition of rifampin in the last 5 days. RESULTS: Although all the patients studied met the criteria of the reported preliminary study, we were unable to detect any evidence of improvement in their psoriasis. CONCLUSION: There was no apparent benefit for patients with streptococcus-associated psoriasis from a course of oral penicillin or erythromycin with the addition of rifampin in the last 5 days in a 14-day trial.

Adolescent↗
PubMed1992

Compliance with a nonrecapping needle policy.

Compliance with nonrecapping needle policies is poor. Accidental needlestick injuries account for up to 80% of reported occupational needle exposures, and 45% of needlestick injuries occur at recapping. To determine the degree of compliance with in-house nonrecapping and needle disposal policies, the authors undertook an unannounced survey of needles disposed in designated sharps disposal containers and, via a questionnaire, surveyed attitudes to policies. The results show between 46 and 77% of needles were being recapped with 9 to 20% of bloodstained needles recapped before disposal. Recapping devices were rarely used and two-handed recapping techniques predominated. Highest rates of recapping were seen in intensive care, intermediate care and medical care units. Common reasons for recapping include inability to dispose immediately of needles properly, and sharps containers being too far away. Awareness of the risks of recapping was widespread with over 90% of respondents having been instructed in proper needle disposal techniques. While few health care professionals disagreed with non-recapping and needle disposal policies, many--for various reasons--persist in hazardous needle disposal practices.

Health Knowledge, Attitudes, Practice↗
PubMed1991

Epidemiological investigation of the association between infectious mononucleosis and multiple sclerosis.

By matching a cohort of 494 infectious mononucleosis (IM) cases with a multiple sclerosis (MS) register, 3 MS cases were retrieved. The interval between IM and MS was 12 years. This corresponds to a relative risk of 3.7 for MS to occur subsequent to IM (p = 0.05). This relationship between a manifestation of a relatively late Epstein-Barr virus infection and MS may indicate that a microbiologically shielded environment is important in the pathogenesis of MS.

Adolescent↗
PubMed1990

The dichotomous distribution of gastrinomas.

Our experience with 47 sporadic gastrinomas suggests that no less than 85% of these tumors are located to the right of the superior mesenteric artery. This finding is unexpected because approximately 75% of insulinomas and glucagonomas are located to the left of the superior mesenteric artery. All of our extrapancreatic gastrinomas have been located to the right. These observations prompted us to determine if other extrapancreatic gastrinomas were also predominantly located to the right side. We searched the world's literature and found 10 cases of ovarian gastrinomas and one case of a renal gastrinoma. Nine of these remote extrapancreatic gastrinomas were located on the right side. This distribution of remote extrapancreatic gastrinomas is similar to our experience with peripancreatic gastrinomas. This unexpected right-sided preponderance of both remote and peripancreatic gastrinomas suggests a common origin for both.

Adult↗
PubMed1989

Muscle cell potassium, RNA and hydration in pregnancy and pre-eclampsia.

Thirty four pregnant women from 26 to 38 weeks gestation and 24 pregnant women with pre-eclampsia gave samples of muscle (rectus abdominis) at caesarean section. Muscle samples were analysed for H2O, K+, Mg2+ and Na+. Cell extracellular H2O was partitioned by the use of the Cl- space. Also protein, nucleic acids and Zn2+ were determined. From 26 to 38 weeks gestation the concentration of K+ per litre of cell water ([Ki]) slowly declined. The slope was significant. Points for patients with pre-eclampsia fell below the line and analysis of covariance showed that the two populations were different (P less than 0.001). Patients A-J were regarded clinically as severe pre-eclamptics. Points for these patients, in general, fell between 1 and 2 SDs below the normal line. Since other cations per litre of muscle cell water did not change, questions are raised. is the cation gap filled by amino acids or does vascular spasm cause a leakage of K+ from muscle cells? Does hypotonicity eventually develop leading to water intoxication? The low oncotic pressure in pre-eclampsia (shown here), the negative free water clearance could all favour increased cell hydration (some evidence for this is presented here towards term). Assessment of available information concerning creatinine excretion during normal pregnancy and K40, K42 studies together with our own rodent studies leads us to believe that a significant increase in muscle mass occurs, but such may not be the case in pre-eclampsia since the reduction in RNA and Zn2+ concentrations in muscle would suggest excessive protein degradation.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdominal Muscles↗
PubMed1989

Laboratory diagnosis and clinical significance of rubella in children with cancer.

Virus-specific antibody responses were studied in 12 children with cancer in whom rubella was diagnosed by seroconversion or a rising titre (greater than or equal to fourfold) of haemagglutination inhibiting (HI) antibody. Our results confirmed the difficulties of making a diagnosis of rubella infection in immunocompromised children using criteria for interpreting antibody assays established in immunocompetent patients. Specific IgM antibody persisted for more than 2 months in 7 of 10 children with probable primary rubella, 3 of whom had high concentrations of such antibody 6, 7 and 11 months after the rash. Radial haemolysis and specific IgG1 and IgG3 antibody responses were low in 4, 2, and 4 patients, respectively. One child apparently had a rubella reinfection and, in another, rubella antibody passively acquired from blood transfusions was probably responsible for the HI seroconversion. Nonetheless, the benign clinical course of rubella in immunocompromised children was confirmed.

Antibodies, Viral↗
PubMed1987

Cloning and characterization of an abundant Plasmodium knowlesi antigen which cross reacts with Gambian sera.

A 110 kDa Plasmodium knowlesi antigen, termed PK110, has been identified on the basis of messenger RNA abundance in late schizonts. Most Plasmodium genes previously cloned have been identified by immune sera, which have selected immunodominant antigens composed of repeating epitopes. Although PK110 was not selected by immune sera, it also contains amino acid repeats, indicating that this structure may be a common feature of malarial proteins. Determination of 296 codons in the PK110 gene revealed the presence of thirteen tandem repeats of twelve amino acids whose consensus sequence is E E T Q K T V E P E Q T. A termination codon interrupts the fourteenth repeat, indicating that these repeats are at the C-terminus of the protein. Indirect immunofluorescence experiments with sera raised against the lambda gt11 fusion protein indicate that PK110 is present in intra-erythrocytic late schizonts. Cloned PK110 is recognized by Gambian sera, and shares epitopes with Plasmodium ovale. PK110 does not cross react immunologically or by DNA hybridization with Plasmodium falciparum.

Amino Acid Sequence↗
PubMed1987

Simultaneous resection of synchronous bilateral bronchogenic carcinoma using median sternotomy.

Despite the increasing use of median sternotomy for pulmonary resection, only two successful cases of simultaneous resection of bilateral primary bronchogenic carcinoma by this approach have been reported. We report the third case of successful resection of synchronous primary bronchogenic carcinoma by median sternotomy, and the fourth successful case of simultaneous resection, as the first reported case of simultaneous resection was accomplished via bilateral anterolateral thoracotomy incisions. We believe at present that the ideal surgical approach for patients with bilateral primary bronchogenic carcinoma is simultaneous resection by median sternotomy.

Carcinoma, Bronchogenic↗