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Biomedical subjects

J M Graham

Publications and source records attributed to J M Graham.

At least 163 records · Page 9Linked to original sources
PubMed1990

Distal femoral physeal problem fractures.

Treatment options in the past for distal femoral physeal fractures have varied from closed reduction to open reduction with internal fixation to balanced skeletal traction. In this study, ten patients with distal femoral physeal fractures treated with closed reduction and casting or skeletal traction are reviewed. Seven fractures lost position in comparison with original reduction films. Nine patients developed subsequent deformity. No consensus exists regarding the use of open versus closed treatment with internal fixation. This review of closed treatment yielded a high rate of unacceptable results. Initial anatomic reduction with rigid fixation of physeal injuries about the ankle has been demonstrated to decrease the incidence of growth deformity. The authors' experience and a review of the literature suggest that a similar approach is applicable to distal femoral physeal fractures.

Adolescent↗
PubMed1989

Angelman and Prader-Willi syndromes share a common chromosome 15 deletion but differ in parental origin of the deletion.

Many Prader-Willi syndrome (PWS) and Angelman syndrome (AS) patients have a cytogenetic deletion of 15q11q13. While AS and PWS share a similar cytogenetic anomaly, they have very different clinical phenotypes. DNAs from 4 AS patients were examined using 5 chromosome 15q11q13-specific cloned DNA segments. With the present level of resolution, the molecular deletions between AS and those previously reported for PWS did not appear to differ. However, in contrast to the paternal inheritance of the deleted chromosome 15 observed in the majority of PWS patients, maternal inheritance of the deleted chromosome 15 was demonstrated in the AS patients by restriction fragment length polymorphisms (RFLPs).

Child↗
PubMed1989

Acrocallosal syndrome: new findings.

We describe a 21-month-old girl with typical manifestations of the acrocallosal syndrome of craniofacial anomalies, agenesis of the corpus callosum, hallucal duplication, severe hypotonia, and psychomotor retardation. Our patient also had the Dandy-Walker malformation, imperforate anus with rectovaginal fistula, hypothalamic dysfunction with hypothyroidism and diabetes insipidus, thick, dysplastic pulmonic valve leaflets, central and obstructive apnea, and pulmonary hypertension. These findings add to the delineation of this syndrome.

Abnormalities, Multiple↗
PubMed1989

Restriction fragment length polymorphisms within proximal 15q and their use in molecular cytogenetics and the Prader-Willi syndrome.

Restriction fragment length polymorphisms (RFLPs) are described in detail for 6 DNA probes (D15S9-13, D15S18) that localize to the proximal long arm of human chromosome 15 (15q11-15q13: this report and Tantravahi et al., Am. J. Med. Genet. 33:78-87. Multiple RFLPs are detected by the probe that identifies locus D15S13, and these RFLPs are shown by genomic mapping to result from a nearby insertion or deletion of 1.8 kilobases (kb) of DNA. This set of RFLPs detected by proximal 15q probes can be used for studies on the Prader-Willi syndrome (PWS) and on mentally retarded individuals with a supernumerary inv dup(15) chromosome. Five of the polymorphic loci (D15S9-13) map to the region implicated in the cause of the PWS (15q11.2-15q12). Each of 4 families tested with these probes, as well as an additional "PWS-like" patient, was informative by RFLP analysis. The two PWS deletions studied, which occurred de novo, were inherited from the chromosome 15 provided by the father. By contrast, the 2 inv dup(15) chromosomes analyzed were of maternal origin. The use of RFLPs can also simplify the molecular determination of copy number in chromosomal aneuploidy, as exemplified by analysis of individuals with the PWS and a deletion, patients with an inv dup(15), and one patient with a more complex rearrangement involving chromosome 15. Our studies demonstrate the application of DNA probes for both molecular cytogenetic studies on this chromosome region and the development of diagnostic molecular markers to aid early clinical diagnosis of the PWS.

Chromosome Deletion↗
PubMed1989

Quantitative calibration and use of DNA probes for investigating chromosome abnormalities in the Prader-Willi syndrome.

Ten genomic DNA probes, subcloned from inserts derived from a phage library constructed from the DNA of flow-sorted chromosomes, have now been mapped to locations within 15q11-15q13. By dosage blotting and densitometry, 5 of these probes map to the 15q11.2-15q12 segment missing in one 15 chromosome of a Prader-Willi syndrome (PWS) patient with a prominent cytological deletion. A sixth probe most likely maps to the same region. The other 4 probes map outside of this segment but within 15q11-15q13. Several of the 15q11.2-15q12 probes, and a cDNA probe homologous to one, have been used to test the DNA from 8 patients exhibiting a wide range of the clinical manifestations expected for PWS patients. DNA deletion was observed in all 3 patients with cytological 15q1 deletions as well as in a patient with an unbalanced (Y;15) translocation. DNA from 1 PWS patient with an unbalanced (5;15) translocation and an inverted duplication of the short arm and proximal long arm of 15 showed at least 1 and possibly 2 extra copies of each genomic probe tested. In the other 3 patients with no cytological deletions, no DNA deletions were found. Thus, the molecular probes described can be used in most PWS patients to analyze the region of proximal 15q implicated in this syndrome.

Adolescent↗
PubMed1989

Case report and delineation of the congenital hypothalamic hamartoblastoma syndrome (Pallister-Hall syndrome).

We report one new case of congenital hypothalamic hamartoblastoma syndrome (Pallister-Hall syndrome) and one case of a diencephalic nodule associated with craniofacial malformations. Based on a review of 11 cases of Pallister-Hall syndrome documented by pathological examination, two cases presumed by phenotype, three cases of hypothalamic hamartoma with craniofacial anomalies only, and several cases of related interest, we delineate the clinical, neuroradiologic, and neuropathologic manifestations which aid in differential diagnosis. Clinical manifestations in infants with Pallister-Hall syndrome included postaxial polydactyly with nail dysplasia, short nose with flat nasal bridge, apparently low-set, posteriorly angulated ears, kidney and lung anomalies, congenital heart defects, imperforate anus, and micropenis with undescended or hypoplastic testes in males. These manifestations were associated with varying degrees of panhypopituitarism and pituitary aplasia. In three cases of hypothalamic hamartoma associated with craniofacial anomalies only, the face resembled that of holoprosencephaly. Other cases of hypothalamic hamartoma have had associated palate or heart defects or presented with precocious puberty. Of the infants with a hypothalamic hamartoblastoma at autopsy, neuropathologic findings were consistent with a primitive neuroectodermal tumor. Surgical tissue from our sole survivor suggested such tumors might mature, and the tumor has not recurred. Neuroradiologic diagnosis may be difficult but should be attempted in infants with these clinical manifestations; due to the need for prompt initiation of appropriate therapy.

Cleft Lip↗
PubMed1989

Triploidy: pregnancy complications and clinical findings in seven cases.

Seven cases of triploidy were encountered by the Prenatal Diagnosis Program at Dartmouth-Hitchcock Medical Center over an 8-year period through associated pregnancy complications. We describe the characteristic findings that facilitate prenatal diagnosis and management. Our experience includes fetuses with major central nervous system abnormalities (spina bifida aperta, holoprosencephaly) and anterior abdominal wall defects, which are detectable with routine prenatal diagnostic screening examinations (ultrasound and AFP). In addition, we stress the importance of recognizing obstetric complications and associated cystic placental changes, which are quite common among triploid conceptuses. Molar changes associated with triploidy have a more benign prognosis than that associated with diploid moles. Such molar changes may relate to the presence of a diploid paternal chromosome complement. The usefulness of cytofluorometric DNA determinations in helping to confirm a clinical suspicion of triploidy is emphasized. These cases are presented in an effort to facilitate prenatal recognition and management of this common cytogenetic condition and prevent unnecessary Caesarean section deliveries.

Adolescent↗
PubMed1989

Development of coronary prevention strategies by health authorities in the United Kingdom.

The United Kingdom has one of the highest coronary heart disease mortality rates in the world. However, over the last decade there has been a growing impetus in coronary prevention. In 1988 the Faculty of Community Medicine carried out a survey of all health authorities in the UK to assess the progress and problems with coronary prevention. This survey received a 92 per cent response rate and shows some interesting findings. The picture at present reveals a growing momentum in the last couple of years with half the health authorities at present claiming to have a programme. The main hindrances reported are lack of funding rather than lack of interest. The development and difficulties with nutrition and smoking policies, and with blood pressure screening are also described. The regional pattern of development of these programmes and policies is complex. Many authorities favour a general health promotion approach rather than a negative, disease oriented one; this conflict in approach requires further debate.

Coronary Disease↗
PubMed1989

Osteogenesis imperfecta. The position of substitution for glycine by cysteine in the triple helical domain of the pro alpha 1(I) chains of type I collagen determines the clinical phenotype.

Skin fibroblasts grown from three individuals with osteogenesis imperfecta (OI) each synthesized a population of normal type I collagen molecules and additional molecules that had one or two alpha 1(I) chains that contained a cysteine residue within the triple-helical domain, a region from which cysteine normally is excluded. The patients had very different phenotypes. One patient with OI type I had a population of alpha 1(I) chains in which glycine at position 94 of the triple helix was substituted by cysteine; a patient with OI type III had a population of alpha 1(I) chains in which glycine at position 526 of the triple helix was substituted by cysteine; and the third patient, with OI type II, had a cysteine for glycine substitution at position 718 of the alpha 1(I) chain. From all three patients, molecules that contained two mutant chains formed interchain, intramolecular disulfide bonds, and although less stable to thermal denaturation than normal molecules, they were more stable than molecules that contained only a single mutant chain. These findings indicate that substitutions for glycine within the triple-helical domain of the alpha 1(I) chain are not invariably lethal and that their phenotypic effect largely depends on the nature of the substituting residue and its location in the chain.

Adult↗
PubMed1989

UCH/RNID single channel cochlear implant: surgical technique.

In a series of thirty patients who received single-channel cochlear implants a simple standard operative procedure has been developed. No life-threatening complication and no wound breakdown occurred. The only problems encountered during surgery were related to the position or obliteration of the round window niche. The commonest reason for removing the implant was device failure; this was caused by a single defective electronic component. No further failures have occurred since this was modified. The second commonest reason for failure was related to the position of the implant, both cases occurred early in the series and the operative technique was altered to prevent further episodes. The infection rate has been low, partly because a simple postaural incision does not put the local blood supply to the skin at risk. Synkinetic facial nerve stimulation seems difficult to predict and may be hard to avoid until more is known about its aetiology.

Cochlear Implants↗
PubMed1989

UCH/RNID single channel extracochlear implant: results in thirty profoundly deafened adults.

The University College Hospital/Royal National Institute for the Deaf (UCH/RNID) Cochlear Implant Programme has now given single channel extracochlear implants to forty profoundly deafened adults. Audiological, psychophysical, speech perceptual and subjective results for the first thirty cases are described. The main findings can be summarised as follows: 1. Users of the single channel extracochlear implant gained considerable improvements in their lipreading and communication ability, as assessed by both objective testing and by the patients' own reports. All acquired useful awareness of environmental sounds and an improvement in their quality of life; some also showed improvements in their own speech. A small number were capable of some open-set speech discrimination without lipreading. 2. Extracochlear implantation was not found to destroy residual hearing, although it did cause slight deterioration in hearing thresholds in some cases. 3. Our results so far suggest that patients deafened by meningitis are likely to obtain less benefit from a single channel cochlear implant than those deafened by other causes. Better results were also achieved by younger, more recently deafened patients and those who were good lipreaders. Despite the emergence of these trends we have not yet found a reliable way to predict benefit from an implant on the basis of preoperative variables. 4. Self-reported measures of the benefits of the implant correlated well with the objective test results, but also revealed important information that was not available from the objective tests. In particular, they showed that the improvement in lipreading provided by the implant was reduced in noisy conditions.

Acoustic Stimulation↗
PubMed1988

Subcellular localization of the sulphation reaction of heparan sulphate synthesis and transport of the proteoglycan to the cell surface in rat liver.

We report on the incorporation of radiolabelled sulphate into proteoglycan in the 'in situ'-perfused rat liver. After 5 min virtually all of the [35S]sulphate was incorporated into heparan sulphate; no partially sulphated precursors were detected. Pulse-chase experiments, followed by centrifugation in gradients of sucrose and metrizamide, showed that, at 5 min, the heparan sulphate was associated predominantly with the Golgi membranes. Over the next 20 min, intact proteoglycan appeared at the plasma membrane. At intermediate times the heparan sulphate was detected simultaneously in two distinct populations of membrane vesicles. Whether the heparan sulphate in these two populations has two different destinies (e.g. plasma membrane or secretion) is not yet clear. Subfractionation of the Golgi membranes showed that the N-sulphotransferase co-purified with the heparan [35S]sulphate and was separable from the galactosyltransferase of glycoprotein synthesis, confirming that the Golgi membrane system is functionally segregated. Subfractionation also permitted an almost 100-fold purification of the N-sulphotransferase over the homogenate: this will provide an excellent starting material for isolation and further characterization of the enzyme.

Animals↗
PubMed1988

Ring chromosome 12.

A ring chromosome 12 (p13.3q24.3) was observed in all cells analyzed from skin fibroblasts and the peripheral blood of a 19-year-old man initially referred for developmental delay with expressive language deficiency. Other phenotypic anomalies included growth deficiency, multiple café-au-lait spots, mild pectus excavatum, glandular hypospadias, left esotropia, clinodactyly of the fifth fingers, and hypothyroidism with elevated antithyroid antibodies. The four previously reported cases of r(12) support the theory of a general ring phenotype which is manifested independently of the specific autosome involved and which is characterized by growth failure, moderate mental retardation, and lack of other major phenotypic anomalies. Breakpoints in all cases of r(12) have been assigned to the telomeric regions, suggesting minimal deletion of chromosome material.

Adult↗
PubMed1988

Ion modulation of membrane permeability: effect of cations on intact cells and on cells and phospholipid bilayers treated with pore-forming agents.

Leakage of ions (Na+, K+) and phosphorylated metabolites (phosphorylcholine, 2-deoxyglucose 6-phosphate) through membrane lesions in intact cells or in cells modified by 'pore-forming' agent has been studied. Leakage from intact cells is induced by protons and by divalent cations such as Cu2+, Cd2+ or Zn2+. Leakage from agent-modified cells--or across phospholipid bilayers modified by agent--is prevented by low concentrations of the same cations and by higher concentrations of Ca2+, Mn2+ or Ba2+; Mg2+, dimethonium, spermine, or spermidine are virtually ineffective. The relative efficacy of a particular cation (e.g. Ca2+) depends more on cell type than on the nature of the pore-forming agent. The predominant effect is on binding of cation to specific sites, not on surface charge. Surface charge, on the other hand, does affect leakage from agent-modified cells in that suspension in nonionic media reduces leakage, which can be restored by increasing the ionic strength: univalent (Na+, K+, Rb+, NH4+) and divalent (Mg2+, dimethonium) cations are equally effective; addition of protons or divalent cations such as Zn2+ to this system inhibits leakage. From this and other evidence here presented it is concluded that leakage across membranes is modulated by the presence of endogenous anionic components: when these are in the ionized state, leakage is favored; when unionized (as a result of protonation) or chelated (by binding to divalent cation), leakage is prevented. It is suggested that such groups are exposed at the extracellular face of the plasma membrane.

Animals↗