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Biomedical subjects

M C Jones

Publications and source records attributed to M C Jones.

At least 109 records · Page 6Linked to original sources
PubMed1988

Risk of multiple sclerosis exacerbation during pregnancy and breast-feeding.

Studies in the past have reported an increased risk of exacerbations in multiple sclerosis during the postpartum period; it is not known whether breast-feeding alters this risk. We interviewed 435 women regarding pregnancy and breast-feeding history, providing for analysis 191 pregnancies that had occurred during a nonprogressive phase of the disease. The exacerbation rates during the nine-month postpartum period (34%) were more than three times the exacerbation rate during the nine months of pregnancy (10%). The exacerbation risk was highest in the three-month period following childbirth and appeared to stabilize after the sixth postpartum month. The exacerbation rates in breast-feeding and non-breast-feeding pregnancies were 38% and 31%, respectively. The average time to exacerbation was similar in breast-feeding (3.0 months) and non-breast-feeding (3.1 months) pregnancies. Although differential exacerbation rates during pregnancy and the postpartum period may be related to hormonal effects on the immune system, the hormonal effects of breast-feeding do not appear to similarly affect the risk of exacerbation.

Adolescent↗
PubMed1988

Interstitial and terminal deletions of the long arm of chromosome 4: further delineation of phenotypes.

We reviewed 45 patients with a deletion of the long arm of chromosome 4. Forty-one were previous reports (25 terminal deletions and 16 interstitial deletions) and 4 are new cases with terminal deletions. Of the 29 patients with terminal deletions, 18 with deletion at 4q31 and 4 at 4q32----qter had an identifiable phenotype consisting of abnormal skull shape, hypertelorism, cleft palate, apparently low-set abnormal pinnae, short nose with abnormal bridge, virtually pathognomonic pointed fifth finger and nail, congenital heart and genitourinary defects, moderate-severe mental retardation, poor postnatal growth, and hypotonia. Six patients with a deletion at 4q33 and one patient with deletion 4q34 were less severely affected. In general, patients with various interstitial deletions proximal to 4q31 had a phenotype that was less specific, although mental retardation and minor craniofacial anomalies were also present. There were 3 patients with piebaldism and one with Rieger syndrome. We conclude that terminal deletion of chromosome 4q (4q31----qter) appears to produce a distinctive malformation (MCA/MR) syndrome in which the phenotype correlates with the amount of chromosome material missing and which differs from the more variable phenotype associated with interstitial deletions of 4q.

Abnormalities, Multiple↗
PubMed1988

Laterality defects in conjoined twins: implications for normal asymmetry in human embryogenesis.

We evaluated six pairs of conjoined twins: four pairs were dicephalus, and two were of the ischiopagus type. In three of the four dicephalus pairs, the right twin had an abnormality of laterality that included a right aortic arch, reversed great vessel orientation, bilateral right-sided isomerism of the lungs, asplenia, and situs inversus of the viscera. The left twin had normal great vessel orientation and situs solitus in each case. The finding that was unique in these three dicephalus twin pairs was their fused hearts, which were similar in orientation and configuration. The fourth dicephalus twin pair had one normally rotated heart, which was located in the midline and had normally placed chambers and great vessels. Each twin of this pair had normal visceral situs. In the two pairs of ischiopagus twins, each pair had two separate hearts, with normal cardiac structure and great vessel relationships. The viscera expressed normal laterality. Documentation of a defect in laterality in the right twin in three conjoined twin pairs with fusion of the hearts, combined with the presence of normal laterality in three pairs without cardiac fusion, has implications regarding the mechanisms leading to laterality of the human embryo. We suggest that rotation of the heart initiates the embryo's process of lateralization and that the laterality defects of the viscera seen in the right twin are a result of their abnormal cardiac rotation.

Abnormalities, Multiple↗
PubMed1988

Anterior temporal electrodes in complex partial seizures.

Anterior temporal (AT) and sphenoidal (SP) electrodes as well as standard 10-20 electrodes were used to evaluate patients with recent onset complex partial seizures. A total of 58 epileptiform foci were found in 80 patients. AT electrodes significantly improved detection of foci in comparison with 10-20 electrodes. SP electrodes resulted in a small, non-significant increase in detection in comparison to AT electrodes. AT electrodes may be substituted for basal electrodes for the purpose of diagnosis in the majority of patients with recent onset complex partial seizures.

Electrodes↗
PubMed1988

Cyclosporin A prevents sensitization after blood transfusion in multiparous rats.

1. Humoral immune responses to allogeneic blood transfusions and semi-allogeneic pregnancies were monitored by the indirect haemagglutination assay in strains of inbred rats. 2. Similar titres and ranges of cross-reactive alloantibodies were induced by blood transfusions and pregnancy; the maternal alloantibody response to paternal antigens was not increased by an unrelated antigenic stimulus. 3. Immunosuppression with cyclosporin A was effective in preventing the primary humoral immune response produced by blood transfusion but not in abrogating the established immune response to previous pregnancy. 4. These studies have established an animal model of sensitization that both stimulates the clinical situation of many potential renal transplant recipients and permits analyses of the different antigenic stimuli involved.

Animals↗
PubMed1988

The influence of repeated transfusions and cyclosporine on secondary alloantibody responses in inbred rats.

The influence of cyclosporine (CsA) on secondary and established alloantibody responses was evaluated in inbred Lewis rats and (AO x PVG)F1 hybrid rats. Lewis rats received weekly transfusions of DA whole blood for 8 weeks either with or without cyclosporine (15 mg/kg/day) after sensitization with DA splenocytes. Hybrid rats received only CsA (10 mg/kg/day) after similar sensitization. Administration of CsA did not affect the spontaneous decline in alloantibody titers against class I (RT1A) antigens, but it was associated with a significantly reduced response to class II (RT1B) antigens at the end of the study. CsA prevented maintenance of high alloantibody titers to RT1A antigens in Lewis rats transfused repeatedly following sensitization. IgG alloantibody subclass responses were also altered by CsA with significant reduction in titers of IgG1, 2a, and 2b against RT1A antigens in rats transfused repeatedly; CsA did not, however, suppress IgG2c alloantibody levels in these animals. Responses to public RT1A antigens disappeared in most animals irrespective of their treatment group, whereas those to private and public RT1B antigens persisted unless CsA was administered. The results suggest that, contrary to results obtained with other antigens, CsA does influence secondary alloantibody responses. CsA may thus prove of value in highly sensitized dialysis patients who require further blood transfusions.

Animals↗
PubMed1988

The alloantibody response to semiallogeneic pregnancy in the rat. II. Antibodies in serum directed to multiple epitopes on conventional RT1A antigens.

Evidence for a unique class I MHC antigen (termed Pa), which is believed to be expressed on rat trophoblast during pregnancy and which stimulates alloantibody formation with unusual interstrain cross-reactivity, has been examined in inbred rats. The previously reported pattern of crossreactivity was confirmed but was not unique to antisera produced by pregnancy. Antibody blocking studies using biotinylated rat monoclonal antibodies to distinct epitopes on RT1Aa antigens suggested that antibodies present in pregnancy sera, especially from multiparous rats, reacted with several epitopes on these molecules. Moreover, a rat monoclonal antibody, 381- 1E10, directed against the putative Pa epitope was shown by synergistic lysis and cold antibody competition to be directed to the immunodominant S epitope on RT1Aa. These data argue against the existence of a distinct Pa antigen or epitope detected by pregnancy sera.

Animals↗
PubMed1988

Alloantibody and transferable suppressor activity induced by cyclosporine and blood transfusions in the rat.

The effect of cyclosporine on the alloantibody response to blood transfusion was investigated in inbred strains of rats by IHA and CELISA; recipient animals differed from the donors at the class I (RT1A) or both class I and class II (RT1B) antigens of the major histocompatibility complex. Alloantibody titers stimulated in high responder PVGu/c animals by blood transfusions were attenuated by cyclosporine; this effect was not demonstrated in low responder PVGc rats, as alloantibody titers decreased after further blood transfusions whether or not cyclosporine was given. Cyclosporine not only reduced the initial IgM response but suppressed the subsequent production of IgG. Splenocytes from rats receiving cyclosporine and blood transfusions from donors that differed from the recipients at the class I antigen were effective in suppressing the subsequent antibody response to blood transfusion. When blood transfusions from donors which differed from the recipients at both class I and class II antigenic loci were given after splenocyte transfer, a greater degree of immunosuppression was detected than if the transfusion donor differed only at the class I locus. These data suggest that the sensitization produced by blood transfusions and the persistence or decline of the alloantibody response depend upon the responder status of the recipient. Blood transfusions given with cyclosporine are capable of inducing suppressor activity that is transferable in spleen homogenates. Subsequent alloantibody responses are influenced by the class I and class II disparities of the donor and recipient animals. If these results can be extrapolated to clinical practice, cyclosporine should be given with pretransplant blood transfusions to prevent sensitization, and the transfusion donor should differ from the recipient at both class I and class II antigenic loci.

Animals↗
PubMed1988

Congenital pancreatoblastoma in Beckwith-Wiedemann syndrome: an emerging association.

We present a male newborn (weight 4000 g) who died at age 12 days with a clinical history of persistent hypoglycemia and polycythemia. Clinical examination disclosed somatic hemihypertrophy (left side), a large umbilical hernia, macroglossia, and an intraabdominal tumor, consistent with the diagnosis of Beckwith-Wiedemann syndrome (EMG syndrome) and hemihypertrophy. Necropsy findings included visceromegaly (left kidney and adrenal), cytomegaly of the fetal cortex and nodular arrangement of both adrenals, diffuse nesidioblastosis and islet cell hyperplasia of the pancreas, and persistent glomerulogenesis. The tumor was a cystic pancreatoblastoma attached to the anterior surface of the pancreas. Three other examples of this association, congenital pancreatoblastoma and Beckwith-Wiedemann syndrome, all in males, are on record in the literature, indicating a strong relationship between both conditions.

Beckwith-Wiedemann Syndrome↗
PubMed1988

Is nodular regenerative hyperplasia of the liver associated with azathioprine therapy after renal transplantation?

A 33-year-old man presented with hepatosplenomegaly and ascites 26 months after receiving a successful renal transplant. Immunosuppression consisted of low-dose prednisolone and azathioprine. Biopsy showed characteristic features of nodular regenerative hyperplasia of liver (NRHL), a condition which may be related to azathioprine therapy but has rarely been reported in association with renal transplantation.

Adult↗
PubMed1988

Fitting time-dependent multicompartment models: a case study.

A multicompartment model with time-dependent transfer rates is fitted to data on ovarian follicle dynamics in mice. The fitted model arises from an interplay between parametric and nonparametric approaches to fitting curves to these data. Nonparametric regression estimates, in the form of spline smoothers, are used in conjunction with the biologically meaningful general class of multicompartment models to suggest refinements to the parametric model. One result of this interplay is the suggestion of using three-stage step functions for the compartmental transition rates; the resulting curves mimic closely the nonparametric regression estimates.

Animals↗
PubMed1988

Etiology of facial clefts: prospective evaluation of 428 patients.

This article presents the results of prospective evaluation of 428 patients with facial clefts or velopharyngeal insufficiency who were evaluated through the Cleft Palate Program at Children's Hospital, San Diego. Children were examined for patterns of major and minor malformations, and an attempt was made to identify the etiology of the overall pattern of altered structure. Results indicate that 14 percent of 259 patients with cleft lip +/- cleft palate, 55 percent of 139 patients with cleft palate, 75 percent of 24 patients with velopharyngeal insufficiency, and 83 percent of 6 patients with atypical clefts had a multiple malformation syndrome. The frequency with which syndromic clefting occurs is higher than previously recognized. Recognition of underlying etiology is important with respect to prognosis and recurrence risk counseling of families and patients. In addition, the underlying diagnosis may significantly impact outcome of medical and surgical treatment of the cleft disorder.

Abnormalities, Multiple↗
PubMed1987

Duplication of distal 15q: report of five new cases from two different translocation kindreds.

Four children and one spontaneously aborted fetus from 2 separate families have a similar pattern of malformation secondary to duplication of distal 15q. In both families, the abnormal chromosomes were derived from balanced reciprocal translocations carried by the mothers. Clinical features common to the 4 liveborn children include appropriate birth weight, length, and head circumference for gestational age; similar craniofacial anomalies, including sloping forehead, bulbous nose, prominent nasal bridge and septum, midline crease in the lower lip, and micrognathia; arachnodactyly; joint contractures involving hands and feet; cardiac defects; and genital anomalies. The 2 infants with duplication 15q22.1----qter and deletion 13q32.3----qter died in the immediate neonatal period. The abortus, who shared the same chromosome constitution, had an omphalocele and a cephalic defect in neural tube closure. The 2 children with duplication 15q22----qter and deletion 11q25----qter survived but have severe psychomotor retardation and postnatal onset growth deficiency, at 48 and 30 months, respectively. The findings in these 5 cases plus review of the literature permit further delineation of a recognizable pattern of malformation secondary to duplication of distal 15q.

Abnormalities, Multiple↗
PubMed1987

A patient with extreme variation in number and size of small marker chromosomes.

We describe extensive variation in the morphology and number of small marker chromosomes in a young girl whose most significant clinical findings were pulmonic stenosis, neck webbing, proptosis, camptodactyly, and developmental delay. Many of the markers had a ring structure. Some were clearly rod-shaped chromosomes with varying arm ratios and others were so small that we could not determine their structure.

Abnormalities, Multiple↗