PubMed Health⌕ Search

Biomedical subjects

H S Williams

Publications and source records attributed to H S Williams.

At least 19 recordsLinked to original sources
PubMed1999

Requirement of a novel gene, Xin, in cardiac morphogenesis.

A novel gene, Xin, from chick (cXin) and mouse (mXin) embryonic hearts, may be required for cardiac morphogenesis and looping. Both cloned cDNAs have a single open reading frame, encoding proteins with 2,562 and 1,677 amino acids for cXin and mXin, respectively. The derived amino acid sequences share 46% similarity. The overall domain structures of the predicted cXin and mXin proteins, including proline-rich regions, 16 amino acid repeats, DNA-binding domains, SH3-binding motifs and nuclear localization signals, are highly conserved. Northern blot analyses detect a single message of 8.9 and 5.8 kilo base (kb) from both cardiac and skeletal muscle of chick and mouse, respectively. In situ hybridization reveals that the cXin gene is specifically expressed in cardiac progenitor cells of chick embryos as early as stage 8, prior to heart tube formation. cXin continues to be expressed in the myocardium of developing hearts. By stage 15, cXin expression is also detected in the myotomes of developing somites. Immunofluorescence microscopy reveals that the mXin protein is colocalized with N-cadherin and connexin-43 in the intercalated discs of adult mouse hearts. Incubation of stage 6 chick embryos with cXin antisense oligonucleotides results in abnormal cardiac morphogenesis and an alteration of cardiac looping. The myocardium of the affected hearts becomes thickened and tends to form multiple invaginations into the heart cavity. This abnormal cellular process may account in part for the abnormal looping. cXin expression can be induced by bone morphogenetic protein (BMP) in explants of anterior medial mesoendoderm from stage 6 chick embryos, a tissue that is normally non-cardiogenic. This induction occurs following the BMP-mediated induction of two cardiac-restricted transcription factors, Nkx2.5 and MEF2C. Furthermore, either MEF2C or Nkx2.5 can transactivate a luciferase reporter driven by the mXin promoter in mouse fibroblasts. These results suggest that Xin may participate in a BMP-Nkx2.5-MEF2C pathway to control cardiac morphogenesis and looping.

Amino Acid Sequence↗
PubMed1982

Psychosocial problems in chronically ill children: physician concern, parent satisfaction, and the validity of medical records.

This study concerns the psychosocial aspects of treatment for chronically ill children. The English-speaking parents of 44 children 5-13 years of age being seen at five specialty clinics at a large county hospital in Los Angeles, and their attending physicians, were the subjects in this study. The parents were interviewed concerning their expectations for the current visit, and the doctor-patient interaction was tape-recorded. Identical categories of information were abstracted from the tape recording and from a chart review of the patients' medical records. Although parents expected 76% of the psychosocial aspects of care to be covered by the doctor, only one fourth were actually discussed in the visit. These unfulfilled expectations were associated with lower satisfaction with medical care received (r = .47, p less than 0.01). Finally, while doctors recorded about 80% of discussions of symptoms and physical examinations in the patient's medical record, they recorded only 25% of discussion of psychosocial problems.

Adolescent↗
PubMed1981

Conformation therapy at the Royal Free Hospital. A progress report on the tracking cobalt project.

A computer-controlled tracking cobalt unit (CCTCU) was commissioned for treating patients in January 1980. The system has proved to be reliable and acceptable in routine use for conventional and conformation therapy. The system comprises a modified TEM MS90 Mobaltron, a Hewlett-Packard System 1000 Model 30 mini-computer and user programmes. Tracking techniques are suitable for the treatment of tumours of the oesophagus, thyroid, bronchus, chains of lymph nodes or medulloblastoma. Tumours 85 cm long can be treated at the isocentre. The high dose volume may be considerably reduced when tracking techniques are used instead of conventional techniques. The major obstacle to the routine use of conformation therapy is treatment planning. Work in progress is designed to produce a computerized planning system linking a CT scanner and the CCTCU. It is expected that the system will produce both a plan optimized in 3-D and the necessary control data in machine readable form within an hour of a patient being scanned. The present planning system is based on a Rad-8 planning system and an Alderson phantom to verify the dose distribution in 3-D. An outline of the tracking technique is given. The computer control system is described briefly, with its methods of use for treating patients. Brief reverence is made to work at other centres using conformation therapy.

Cobalt Radioisotopes↗