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Biomedical subjects

R P Erickson

Publications and source records attributed to R P Erickson.

At least 127 records · Page 7Linked to original sources
PubMed1990

A familial form of convulsive disorder with or without mental retardation limited to females: extension of a pedigree limits possible genetic mechanisms.

An unusual pedigree of female-limited seizures with or without mental retardation is updated. The disorder was first detected in a large cohort of women whose fathers were brothers, and affected women had previously transmitted the disorder. Four brothers of affected females have now had five unaffected daughters while four affected women have had four affected and one unaffected daughters and two unaffected sons. This unusual transmission pattern is discussed in terms of germ-line imprinting, neuronal sexual differentiation, and the generally higher risk of seizures seen when the mother, rather than the father, is affected.

Child, Preschool↗
PubMed1989

A genomic clone of Zfy-1 from a YDOM mouse strain detects post-meiotic gene expression of Zfy in testes.

In order to obtain a genomic clone of Zfy-1 from a Y chromosome of Mus musculus domesticus (YDOM) origin, we cloned size-fractionated SJL/J DNA in EMBL-4 and selected colonies which hybridized to pDP1007, a human zinc finger Y clone. The specificity of the clone in hybridizations to mouse and human DNA and partial sequencing confirmed that the clone (subcloned as pGZfy1D) was of Zfy-1 origin. Studies on the expression during testicular development of mRNAs hybridizing to the clone suggested that the gene is expressed post-meiotically.

Aging↗
PubMed1989

Use of antisense RNA to help identify a genomic clone for the 5' region of mouse beta-glucuronidase.

It was possible to gauge the inhibition of mouse beta-glucuronidase expression by injecting RNA, made from both strands of subclones of a cosmid containing the complete gene, into mouse blastomeres at the four-cell stage. Although our initial screen did not identify the 5' region, we were able to isolate a subclone containing homology to 20 bp coding for N-terminal amino acids of rat and human beta-glucuronidase structural genes. Antisense RNA prepared from one strand of the 350 bp Pst I subclone inhibited beta-glucuronidase expression by 89% while RNA prepared from the other strand had little effect. The subclone appears to correspond to the 350 bp fragment identified by others as one including the ATG start site of mouse beta-glucuronidase.

Animals↗
PubMed1989

Sex vesicle "entrapment": translocation or nonhomologous recombination of misaligned Yp and Xp as alternative mechanisms for abnormal inheritance of the sex-determining region.

Abnormal inheritance of the sex determining region, normally located on Yp, results in about 1 in 20,000 phenotypic males with a 46,XX genotype. Studies to date indicate that many 46,XX males apparently arise due to a balanced, yet abnormal, nonhomologous interchange of Xp and Yp termini. However, 2 of the 5 XX males we report here have 3 copies of the pseudoautosomal locus, MIC2. Thus, they appear to have inherited the sex determining region as a result of Yp sequences being added onto the X pseudoautosomal region. Such an unequal, extremely nonhomologous interchange could alternatively be considered to arise from an unbalanced translocation of Yp to Xp. Our results suggest that very unequal interchange or translocation of Yp sequences onto the X pseudoautosomal region is not as rare a mechanism for XX males as originally thought. We also suggest that sex vesicle "entrapment" favors the association of a Yp fragment to the X pseudoautosomal region over a translocation to either Xq or an autosome.

Blotting, Southern↗
PubMed1989

Re-evaluation of new X-linked syndrome for evidence of CHARGE syndrome or association.

Previously, we reported on a family with a new syndrome of cleft palate, coloboma, hypospadias, deafness, short stature, and radial synostosis. This family has been cited in several reports as an example of familial CHARGE syndrome. We do not think that the patients in this family have the Charge syndrome or association. Therefore, we decided to do a follow-up study on this family to assess the subsequent development of the patients and to determine if they have the CHARGE syndrome. We conclude that our patients do not have familial CHARGE syndrome.

Abnormalities, Multiple↗
PubMed1989

Northern analyses using single-stranded probes do not support a role for GATA/GACA repeats in sex determination in mice and men.

The possible role of GATA/GACA repeated sequences in mammalian sex determination was investigated using Northern analyses of mouse and human RNA. Brain, liver, and gonadal RNA from three developmental stages of mice of both sexes and also human fetal RNA from various tissues were hybridized to both sense and antisense Bkm riboprobes as well as to the synthetic oligonucleotide (GATA)5. At low levels of stringency, putative transcripts of various sizes were observed in all tissue samples with all probes. At high stringency, only a putative transcript of approximately 12 kb was observed, but this was later shown to consist of contaminating DNA. No sex-specific differences were observed in any tissue or developmental stage. Thus, we find no evidence that the GATA/GACA repeated sequences are specifically expressed in quantities detectable by Northern analyses in a manner important to mammalian sex determination.

Animals↗
PubMed1989

A rapid method for detection of Y-chromosomal DNA from dried blood specimens by the polymerase chain reaction.

The alphoid satellite family is the only repetitive DNA family showing chromosome specificity. We have developed a simple, rapid, and reliable test for sex diagnosis based on detection of these sequences in undigested genomic DNA using the polymerase chain reaction. In our test, dried blood specimens were the source of DNA. When female DNA was used as a template for the reaction, only the expected 130-bp X-chromosome-specific fragment was detected, while with male DNA both the expected 170-bp Y-chromosome-specific and X-chromosome-specific fragments were detected. The Y-chromosome-specific fragment was further characterized by restriction enzyme analysis. The Y fragment was detectable when DNA obtained from an equivalent of 10 microliters of spotted blood was used in the reaction, whereas detection of the X fragment was possible with DNA from an equivalent of 5 microliters of blood. Our test may find various applications in newborn screening and in forensic science.

Blood↗
PubMed1989

Characterization of GATA/GACA-related sequences on proximal chromosome 17 of the mouse.

Autosomal loci have long been thought to have a role in sex determination of mice. We studied the localization of GATA/GACA repeats on chromosome 17 in regard to the possibility of their involvement in sex determination. We performed in situ hybridizations on chromosome 17s carrying the Hairpain tail (Thp) deletion of the T locus since this deletion has been associated with sex reversal and hermaphroditism. We did not detect a significant decrease in the amount of hybridization of GATA/GACA repeats to the Thp deletion. In addition, three Bkm-positive cosmids from proximal chromosome 17 did not contain sequences deleted in Thp or TOrl and a fetal testes cDNA probe did not hybridize to the cosmid sequences. Although we confirmed the localization of Bkm-related sequences on chromosome 17, we were not able to relate GATA/GACA sequences on chromosome 17 to sex determination in mice.

Animals↗
PubMed1989

EMG muscle scanning: stability of hand-held surface electrodes.

Electromyographic (EMG) muscle scanning measures 2-second samples of integrated muscle action potentials from individual neck and back muscles using a hand-held scanner with post-style surface electrodes separated by a fixed distance. This "scanning" technique is widely used to expeditiously assess muscle activity in the diagnosis of musculoskeletal disorders. In order to determine if the 2-second sample is sufficiently representative of electrical activity at a specific muscle site, the stability of the signal received by the hand-held scanner was measured bilaterally at six neck and back muscle sites over 40 seconds (20 2-second integration periods) in five seated subjects. Taking the overall average EMG activity as the "true" value, the mean number of 2-second integration periods required to achieve less than 5% standard error was calculated to be 1.47 for the 60 muscles tested. Only three sites required more than five integration periods. The validity of EMG scanning as a diagnostic tool is enhanced by longer integration periods.

Action Potentials↗
PubMed1989

Rehabilitation in multiple sclerosis.

Despite the lack of a definitive remedy for central nervous system demyelination in multiple sclerosis, certain manifestations of the disease are treatable. Recognition and identification of specific impairments, disabilities, and handicaps faced by the patient afford the physician the best opportunity to provide effective intervention. Impairments are ameliorated with difficulty; however, when comprehensive methods of rehabilitation are applied to the associated disabilities and handicaps, meaningful improvements can be achieved. The goal of rehabilitation in multiple sclerosis is to maximize the patient's physical, emotional, social, and vocational independence. Through the multidisciplinary efforts of numerous health-care workers in close cooperation with the patient and the family, this goal can be attained.

Ataxia↗
PubMed1989

Abnormal development and dye coupling produced by antisense RNA to gap junction protein in mouse preimplantation embryos.

Antisense RNA to the 27/32-kDa rat liver gap junction (GJ) protein was used to explore the role of GJs in preimplantation embryos. When all blastomeres of two- and four-cell embryos were injected with GJ antisense RNA, the percentage of embryos compacted at 60 hr of development was reduced to less than 20%, while 90% of uninjected embryos and 75% of embryos injected with an unrelated RNA were compacted. When most cells of compacted eight-cell embryos were injected with the GJ antisense RNA, 20% of the embryos were decompacted and only 5% had developed to the blastocyst stage at 90 hr, when blastulation had occurred in 90% of the control embryos. When antisense RNA was injected in one blastomere of four-cell embryos, 40% of the embryos presented a large cell that was not included in the compacted embryo at the time of compaction, and an additional 30% of the embryos had two smaller, excluded blastomeres. These excluded cells were identified as the injected cell with a rhodamine-conjugated dextran marker. To assess effects on junctional communication, one blastomere of some embryos was injected with Lucifer yellow, a GJ-penetrating dye, at various times after a blastomere was injected with antisense RNA. The dye was visible in the whole cell mass of control embryos, but it was excluded from a portion of experimental embryos when the delay between the RNA and the Lucifer yellow injections was 1 hr or longer.

Animals↗
PubMed1989

A refined genetic map of the region of chromosome 17 surrounding the von Recklinghausen neurofibromatosis (NF1) gene.

The von Recklinghausen neurofibromatosis (NF1) gene has been mapped to the pericentromeric region of chromosome 17. We conducted linkage analyses of NF1 by using 10 polymorphic DNA markers from this chromosomal region. We ascertained 20 American Caucasian NF1 families (163 individuals, 98 NF1 affected) in Michigan and Ohio and also studied a large family ascertained primarily in North Carolina. The following markers were used in this study: HHH202, TH17.19, D17Z1, ERBA1, EW203, EW206, EW207, EW301, CRI-L581, and CRI-L946. NF1 did not recombine with either TH17.19 or HHH202 in any of the informative meioses surveyed (maximum lod scores of 17.04 and 7.21, respectively, at a recombination fraction of .00), indicating that these markers map very close to the NF1 gene. We also report evidence of three instances of recombination between NF1 and the centromeric marker D17Z1 (maximum lod score of 13.43 at a recombination fraction of .04), as well as two crossovers between pairs of marker loci. We find no evidence of locus heterogeneity, and our results support the localization of the NF1 gene to proximal chromosome 17q.

Chromosome Mapping↗
PubMed1989

An extended long-range restriction map of the human sex-determining region on Yp, including ZFY, finds marked homology on Xp and no detectable Y sequences in an XX male.

We have used pulsed-field gel electrophoresis to study the short arm of the Y chromosome by using a pseudoautosomal probe (MIC2Y) and adjacent Y-specific sequences 27a and 47z (DSXY5) in XX males and XY females, in order to detect chromosomal breakpoints which may have given rise to these individuals. The preliminary published long-range restriction map was used as a basis for this study. Our data confirm the reported fragment sizes and resolve some discrepancies. In addition, the recently cloned ZFY locus, pDP1007, the putative sex-determining locus, has been used to extend this long-range restriction map on Yp. Thus far, the X and Y copy of this sequence appear to have conserved GC islands around this locus, since it is found on a 280-kb fragment in males and females by using SacII, BssHII, NarI, and NotI. Only two Y-specific sequences of 50 and 70 kb have been detected at the pulsed-field level by using SfiI and NaeI, respectively. No translocation breakpoints have been detected in any of the patients studied. One XX male, GM1889, however, does not have any of the Y-specific fragments detected using conventional or pulsed-field gel electrophoresis. This is one of the few typical XX males who therefore does not have the ZFY copy of the TDF clone. Since all the other XX males hybridized to 47z, which is centromeric to ZFY, a series of DNA loci that are centromeric to 47z need to be studied in order to detect chromosomal breakpoints.

DNA Probes↗