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Biomedical subjects

M J Griffiths

Publications and source records attributed to M J Griffiths.

At least 55 records · Page 3Linked to original sources
PubMed1991

A single lymphocyte culture for fragile X induction and prometaphase chromosome analysis.

A single lymphocyte culture system is described which produces both reliable fragile X expression and elongated chromosomes for prometaphase analysis. This system, which is based on that described by Wheater and Roberts in 1987, involves the deoxycytidine release of a thymidine block. Eight fragile X positive subjects had an average expression level of 26%, with a range of 12% to 45%, using the thymidine/deoxycytidine protocol. This was comparable to the levels obtained in parallel cultures treated with thymidine alone or fluorodeoxyuridine.

Adolescent↗
PubMed1991

Adenosine as a vasodilator in primary pulmonary hypertension.

BACKGROUND: The acute administration of vasodilator drugs to patients with primary pulmonary hypertension has been advocated to identify those with reversible pulmonary vasoconstriction. Unfortunately, the usefulness of the drugs currently available is limited by accompanying systemic hypotension. A vasodilator with effects confined to the pulmonary circulation would therefore be advantageous in such patients. METHODS AND RESULTS: The purine nucleoside adenosine was infused into the pulmonary artery in seven patients with primary pulmonary hypertension (baseline pulmonary vascular resistance [PVR], 442-1,295 dyne/cm/sec-5) to determine its effect on PVR. In all patients, there was a dose-dependent and significant reduction (mean maximal percent decrease from baseline, 38.9%; p less than 0.001) in PVR mediated through a decrease in pulmonary artery pressure and an increase in cardiac output. Systemic vascular resistance (SVR) also decreased, but the ratio of PVR to SVR decreased (maximal mean percent decrease from baseline) by 10.5% (p less than 0.025), indicating that adenosine has a preferential vasodilator effect on the pulmonary circulation when administered in this manner. CONCLUSIONS: Because of its pharmacokinetic and vasodilator properties, adenosine may have a specific role in the investigation of primary pulmonary hypertension.

Adenosine↗
PubMed1990

Terminal deletion (14)(q32.3): a new case.

A mildly dysmorphic, 2 year old girl with mental retardation was found to have a small de novo terminal deletion of the long arm of chromosome 14, del(14)(q32.3). She was found to have features in common with two previous terminal deletion cases and particularly with the well documented ring 14 syndrome, although seizures, a characteristic feature of ring 14, were notably absent.

Child, Preschool↗
PubMed1989

Orofacial manifestations of a group of British patients infected with HIV-1.

The orofacial manifestations of 44 HIV-infected individuals from the South West of England are reported. Oral candidiasis, periodontal disease and cervical lymphadenopathy were the most commonly observed disorders although hairy leukoplakia was also present in 15% of patients. The orofacial features of this group of British patients are similar to those of HIV-infected individuals from other parts of Europe, North America and Scandinavia.

Acquired Immunodeficiency Syndrome↗
PubMed1989

An unusual case of mosaic Down's syndrome involving two different Robertsonian translocations.

A baby girl with some of the stigmata of Down's syndrome was found to be a mosaic with three different cell lines: 45,XX,-13,-21,+t(13q21q)/(46,XX/46,XX, -21,+t(21q21q). The chromosome rearrangements detected in this patient appear to have arisen de novo. In the normal cell line the terminal end of the p arm of one chromosome 21 is thought to have been damaged. It seems probable that this is related to the other chromosomal anomalies found.

Chromosome Banding↗
PubMed1988

Direct and short-term culture preparation of chorionic villi. Is any one method best?

Chorionic villi from 20 diagnostic cases were prepared for cytogenetic analysis by a direct and two short-term culture methods. No significant differences were found between the methods in the quality and quantity of metaphases obtained. A further study using villi from 20 pre-termination patients indicated an inherent variation in the quality of villi resulting in inconsistent processing and variation in the response of a sample to the methods. This suggests that it would be advantageous to process the villi by more than one method.

Cells, Cultured↗
PubMed1988

Are double translocations double trouble?

Double translocation heterozygotes are rare, but need not necessarily pose more of a counselling problem than single reciprocal translocation heterozygotes. Nine cases of double translocation are presented, together with a review of the few reports published to date. An attempt is made to provide simple counselling guidelines in the assessment of the risk of producing a liveborn abnormal child. This is not based on theoretical considerations of segregation patterns, but extrapolated from what is known empirically about the viable segregation patterns in carriers of single reciprocal translocations. It assumes that there is no interference with the independent assortment of the two separate exchanges, unless a common participating chromosome is involved. The possibility of an interchromosomal effect has not been taken into consideration.

Congenital Abnormalities↗
PubMed1987

Chromosome abnormalities involving band 13q14 in hematologic malignancies.

Fifteen patients with hematologic disorders showed abnormalities involving chromosome band 13q14. Nine patients had an interstitial deletion of this band, similar to that reported in some retinoblastoma tumors and as a constitutional abnormality in a small proportion of cases of familial retinoblastoma. In five patients, band 13q14 was involved in translocations and in one case there was a deletion of one chromosome #13 and a translocation involving the homologous #13. The diagnosis in the majority of our patients (11 of 15) was chronic lymphocytic leukemia. In these patients the abnormalities were detected in cultures stimulated with 4-phorbol 12-myristate 13-acetate (PMA). It is possible that the utilization of this agent is a fundamental requirement for the reliable demonstration of abnormalities involving 13q14 in patients with B-cell malignancies. The incidence of abnormalities involving 13q14 and their significance in the development of neoplasias, other than retino-blastoma, is discussed.

B-Lymphocytes↗
PubMed1987

Antimicrobial prophylaxis of infective endocarditis: effect of BSAC recommendations on compliance in general practice.

General dental practitioners in the South West Region of the U.K. were surveyed to assess compliance with the recently published recommendations of the British Society for Antimicrobial Chemotherapy on the antimicrobial prophylaxis of infective endocarditis. For the majority of dental patients, the level of prophylaxis had improved compared with previous reports: 75% of practitioners organized the prophylaxis themselves, 80% gave oral amoxycillin to penicillin non-allergic patients, and 86% gave erythromycin to penicillin-allergic patients. Some 51% complied to an acceptable level with recommended amoxycillin schedules but only 2% complied with erythromycin schedules. The BSAC recommended prophylactic regimens have certainly improved compliance although they are not yet universally accepted.

Anti-Infective Agents↗
PubMed1975

Telemetry and the study of vertical jaw relations.

A method of monitoring vertical jaw separation over extended periods by radiotelemetry is given. The patterns of mandibular movement evoked by different activities such as rest, work, sleep and swallowing and the effect of a bite-raising splint are described. The influence of gravity and friction on mandibular rest position is discussed. The results were consistent with the view that the rest position of the mandible is determined by passive soft tissue balance, but subject to overriding muscular control as shown when a bite-raising splint was worn.

Deglutition↗
PubMed1975

An intra-oral telemetry system for the continuous recording of vertical jaw movement.

Continuous measurement of the separation between upper and lower dental arches, the so-called interocclusal distance (10D), is of interest in dentistry. Criteria for making such measurements by radio telemetry are discussed. It is concluded that a transmitter small enough to fit in a molar tooth gap is necessary in order to minimize interference with normal function; other design factors are related to obtaining adequate frequency stability, on which measurement accuracy depends. A transmitter fulfilling these requirements is described which sensed the instantaneous value of 10D by the frequency change produced when a metallic object (dental filling, gold crown, shorted turn of wire or piece of ferrite) in one dental arch moved relative to the transmitter in the other. Errors due to lateral and protrusive jaw movements were measured. Careful design and the use of high grade ceramic chip capacitors resulted in a transmitter of good frequency stability (+/- 0.03% in 10 h, +/- 0.02%/degrees c) and small size (10 X 7 X 5 mm). An example is given illustrating 10D movements due to swallowing, speech and respiration.

Humans↗