Biomedical subjects

D J Peters

Publications and source records attributed to D J Peters.

At least 19 recordsLinked to original sources

PubMed2001

[From gene to disease; from polycystines to polycystic kidney disease].

Autosomal dominant polycystic kidney disease (ADPKD) is a genetic disease that results in multiple cysts in the kidneys and other organs and leads to endstage renal failure relatively late in life. The disease results from mutations in one of two independently segregating genes that under normal conditions produce polycystines. Polycystines are membrane proteins that form a complex involved in signal transduction in epithelial cells. Genetic heterogeneity explains in part the various ADPKD phenotypes.

Calcium-Binding Proteins↗

PubMed2000

Polycystin-1, the product of the polycystic kidney disease 1 gene, co-localizes with desmosomes in MDCK cells.

Polycystin-1 is a novel protein predicted to be a large membrane-spanning glycoprotein with an extracellular N-terminus and an intracellular C-terminus, harboring several structural motifs. To study the subcellular localization, antibodies raised against various domains of polycystin-1 and against specific adhesion complex proteins were used for two-color immunofluorescence staining. In Madine Darby canine kidney (MDCK) cells, polycystin-1 was detected in the cytoplasm as well as co-localizing with desmosomes, but not with tight or adherens junctions. Using confocal laser scanning and immunoelectron microscopy we confirmed the desmosomal localization. By performing a calcium switch experiment, we demonstrated the sequential reassembly of tight junctions, subsequently adherens junctions and finally desmosomes. Polycystin-1 only stained the membrane after incorporation of desmoplakin into the desmosomes, suggesting that membrane-bound polycystin-1 may be important for cellular signaling or cell adhesion, but not for the assembly of adhesion complexes.

Animals↗

PubMed2000

Rubinstein-Taybi syndrome caused by a De Novo reciprocal translocation t(2;16)(q36.3;p13.3).

Rubinstein-Taybi syndrome (RTS) is a multiple congenital anomalies and mental retardation syndrome characterized by facial abnormalities, broad thumbs, and broad big toes. We have shown previously that disruption of the human CREB-binding protein (CBP) gene, either by gross chromosomal rearrangements or by point mutations, leads to RTS. Translocations and inversions involving chromosome band 16p13.3 form the minority of CBP mutations, whereas microdeletions occur more frequently (approximately 10%). Breakpoints of six translocations and inversions in RTS patients described thus far were found clustered in a 13-kb intronic region at the 5' end of the CBP gene and could theoretically only result in proteins containing the extreme N-terminal region of CBP. In contrast, in one patient with a translocation t(2;16)(q36.3;p13.3) we show by using fiber FISH and Southern blot analysis that the chromosome 16 breakpoint lies about 100 kb downstream of this breakpoint cluster. In this patient, Western blot analysis of extracts prepared from lymphoblasts showed both a normal and an abnormal shorter protein lacking the C-terminal domain, indicating expression of both the normal and the mutant allele. The results suggest that the loss of C-terminal domains of CBP is sufficient to cause RTS. Furthermore, these data indicate the potential utility of Western blot analysis as an inexpensive and fast approach for screening RTS mutations.

CREB-Binding Protein↗

PubMed2000

Herpes simplex-induced fulminant hepatitis in adults: a call for empiric therapy.

Herpes simplex-induced fulminant hepatitis is an infrequently reported cause of hepatitis in adults. Pregnant females and patients with impaired cellular immunity may be at increased risk, although healthy adults have been affected. The diagnosis may be underrecognized due to nonspecific presenting symptoms and lack of typical cutaneous herpes lesions. We present three cases of fatal herpes simplex fulminant hepatitis. Our review of case reports of herpes simplex hepatitis in adults demonstrates improved survival with intravenous acyclovir therapy. We believe that empiric use of acyclovir should be considered while the diagnostic evaluation of non-acetaminophen-induced fulminant hepatitis is underway. Recognition of characteristic liver function abnormalities seen with fulminant herpes simplex hepatitis include marked elevation of transaminases with AST > ALT and a mild hyperbilirubinemia (anicteric hepatitis), and they should prompt acyclovir therapy. This is especially true when there are no obvious risk factors for other forms of hepatitis.

Acyclovir↗

PubMed2000

The ACE insertion/deletion polymorphism has no influence on progression of renal function loss in autosomal dominant polycystic kidney disease.

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) shows a variable clinical course that is not fully explained by the genetic heterogeneity of this disease. We looked for a possible genetic modifier, the ACE I/D polymorphism, and its influence on progression towards end-stage renal failure (ESRF). METHODS: Forty-nine ADPKD patients who reached ESRF <40 years, and 21 PKD1 patients who reached ESRF > 60 years or were not on dialysis at 60 years of age were recruited. Clinical data were provided by questionnaires. Blood was collected for the determination of the ACE insertion/deletion (I/D) polymorphism genotype. The ACE genotype was also determined in a general, control PKD1 group (n=59). RESULTS: Patients who reached ESRF <40 years had significantly more early onset hypertension than patients reaching ESRF >60 years (80% vs 21%; P<0.001). The ACE genotype distribution showed no differences between the groups of the rapid progressors (DD 20%, ID 56%, II 24%), the slow progressors (DD 29%, ID 52%, II 19%) and the general PKD1 control population (DD 31%, ID 47%, II 22%). CONCLUSION: There is no relationship between progression towards ESRD and the ACE I/D polymorphism in ADPKD patients.

Adult↗

PubMed2000

Outcome of patients with chronic abdominal pain referred to chronic pain clinic.

OBJECTIVE: We determined the outcome of patients with chronic abdominal pain of unknown etiology referred by gastroenterologists to a chronic pain clinic. METHODS: A retrospective chart review of 43 consecutive patients seen by a university-based gastroenterology group was referred to our Chronic Pain Clinic for evaluation and treatment. Pain character and location, the referring diagnosis, and initial Chronic Pain Clinic diagnosis was compared between responders and nonresponders. Early and long-term pain relief was scored by standard questionnaire. RESULTS: Of the 43 patients with chronic abdominal pain of undetermined etiology, 70% reported complete or substantial pain relief by the end of chronic pain management. Pain character and location and the referring diagnosis were not predictors of pain relief. Long-term pain relief was reported by 35% of patients. CONCLUSION: A substantial group of patients with chronic abdominal pain of unknown etiology benefited from Chronic Pain Clinic services.

Abdominal Pain↗

PubMed2000

Diagnostic analysis of the Rubinstein-Taybi syndrome: five cosmids should be used for microdeletion detection and low number of protein truncating mutations.

Rubinstein-Taybi syndrome (RTS) is a malformation syndrome characterised by facial abnormalities, broad thumbs, broad big toes, and mental retardation. In a subset of RTS patients, microdeletions, translocations, and inversions involving chromosome band 16p13.3 can be detected. We have previously shown that disruption of the human CREB binding protein (CREBBP or CBP) gene, either by these gross chromosomal rearrangements or by point mutations, leads to RTS. CBP is a large nuclear protein involved in transcription regulation, chromatin remodelling, and the integration of several different signal transduction pathways. Here we report diagnostic analysis of CBP in 194 RTS patients, divided into several subsets. In one case the mother is also suspect of having RTS. Analyses of the entire CBP gene by the protein truncation test showed 4/37 truncating mutations. Two point mutations, one 11 bp deletion, and one mutation affecting the splicing of the second exon were detected by subsequent sequencing. Screening the CBP gene for larger deletions, by using different cosmid probes in FISH, showed 14/171 microdeletions. Using five cosmid probes that contain the entire gene, we found 8/89 microdeletions of which 4/8 were 5' or interstitial. This last subset of microdeletions would not have been detected using the commonly used 3' probe RT1, showing the necessity of using all five probes.

Amino Acid Sequence↗

PubMed1999

Cellular localization and tissue distribution of polycystin-1.

Autosomal dominant polycystic kidney disease (ADPKD) is characterized by the formation of fluid-filled cysts in both kidneys, in addition to a variety of extra-renal manifestations. The PKD1 gene product, polycystin-1, encodes a novel protein with a putative role in cell-cell/cell-matrix interactions. The present study we focused on the (sub)cellular localization of polycystin-1 in cultured cells, and on its tissue distribution in various organs. In Madin Darby canine kidney (MDCK) cells, several polyclonal antibodies showed intense staining at the sites of interaction between adjacent cells, which remained after Triton extraction. Weak cytoplasmic staining was observed. No signal was detected at the free borders of cell aggregates, supporting a role for polycystin-1 in cell-cell interactions. At the tissue level, polycystin-1 expression was observed in specific cell types in tissues with known manifestations of the disease, but also in tissues of organs which have not been reported to be affected in ADPKD. Expression was frequently seen in epithelia, but also in endocrine cells (pancreatic islets, parathyroid-producing cells, clusters in the adenohypophysis, clusters in the adrenal gland, and Leydig cells in the testis). In addition, expression was observed in myocardium and more weakly in myocytes of cardiac valves, of the cerebral arteries, and of skeletal muscles.

Animals↗

PubMed1999

Genes homologous to the autosomal dominant polycystic kidney disease genes (PKD1 and PKD2).

Autosomal Dominant Polycystic Kidney Disease (ADPKD), a common inherited disease leading to progressive renal failure, can be caused by a mutation in either the PKD1 or PKD2 gene. Both genes encode for putative transmembrane proteins, polycystin-1 and polycystin-2, which show significant homology to each other and are believed to interact at their carboxy termini. To identify genes that code for related proteins we searched for homologous sequences in several databases and identified one partial cDNA and two genomic sequences with significant homology to both polycystin-1 and - 2. Further analysis revealed one novel gene, PKD2L2, located on chromosome band 5q31, and two recently described genes, PKD2L and PKDREJ, located on chromosome bands 10q31 and 22q13.3, respectively. PKD2L2 and PKD2L, which encode proteins of 613 and 805 amino acids, are approximately 65% similar to polycystin-2. The third gene, PKDREJ, encodes a putative 2253 amino acid protein and shows about 35% similarity to both polycystin-1 and polycystin-2. For all the genes expression was found in testis. Additional expression of PKD2L was observed in retina, brain, liver and spleen by RT-PCR. Analyses of five ADPKD families without clear linkage to either the PKD1 or PKD2 locus showed no linkage to any of the novel loci, excluding these genes as the cause of ADPKD in these families. Although these genes may not be involved in renal cystic diseases, their striking homology to PKD2 and PKD1 implies similar roles and may contribute to elucidating the function of both polycystin-1 and polycystin-2.

Amino Acid Sequence↗

PubMed1999

Aberrant splicing in the PKD2 gene as a cause of polycystic kidney disease.

It is estimated that approximately 15% of families with autosomal dominant polycystic kidney disease (ADPKD) have mutations in PKD2. Identification of these mutations is central to identifying functionally important regions of gene and to understanding the mechanisms underlying the pathogenesis of the disorder. The current study describes mutations in six type 2 ADPKD families. Two single base substitution mutations discovered in the ORF in exon 14 constitute the most COOH-terminal pathogenic variants described to date. One of these mutations is a nonsense change and the other encodes an apparent missense variant. Reverse transcription-PCR from patient lymphoblast RNA showed that, in addition, both mutations resulted in out-of-frame splice variants by activating cryptic splice sites via different mechanisms. The apparent missense variant produced such a strong splicing signal that the processed transcript from the mutant chromosome did not contain any of the normally spliced, missense product. A third mutation, a nonconservative missense change effecting a negatively charged residue in the third transmembrane span, is likely pathogenic and defines a highly conserved residue consistent with a potential channel subunit function for polycystin-2. The remaining three mutations included two frame shifts resulting from deletion of one or two bases in exons 6 and 10, respectively, and a nonsense mutation due to a single base substitution in exon 4. The study also defined a novel intragenic polymorphism in exon 1 that will be useful in analyzing "second hits" in PKD2. Finally, the study demonstrates that there are reduced levels of normal polycystin-2 protein in lymphoblast lines from PKD2-affected individuals and that truncated mutant polycystin-2 cannot be detected in patient lymphoblasts, suggesting that the latter may be unstable in at least some tissues. The mutations described will serve as critical reagents for future functional studies in PKD2.

Humans↗

PubMed1999

The angiotensin-converting enzyme genotype and microalbuminuria in autosomal dominant polycystic kidney disease.

Autosomal dominant polycystic kidney disease (AD-PKD) has a variable clinical course. Clinical parameters associated with a worse prognosis are hypertension and proteinuria or microalbuminuria (MA). Because chronic stimulation of the renin-angiotensin system is likely to be present in ADPKD patients, the effect of the angiotensin-converting enzyme insertion/deletion (ACE I/D) genotype on the variability of these clinical parameters was examined in untreated ADPKD patients. Proteinuria and MA were determined in 24-h urine collections. BP measurements were performed with an ambulatory monitor, over 24 h. With analysis of covariance, the ACE genotype was found to be significantly associated with MA, corrected for age, gender, GFR, mean arterial pressure, body surface area, and urinary Na+ excretion (P < 0.05). The patients homozygous for the deletion (DD) had the highest rate of MA (P < 0.05) compared to the patients homozygous for the insertion (II). There was no relationship between the ACE genotype and BP or renal function. A significant positive correlation was found between MA and mean arterial pressure (r = 0.31, P < 0.05), whereas a significant negative correlation was found between MA and renal function (r = -0.28, P < 0.05). In conclusion, in ADPKD patients, MA is partly determined by the ACE I/D polymorphism. Because MA is associated with an enhanced progression toward renal failure, the ACE genotype could help in identifying patients at risk for a worse prognosis.

Adult↗

PubMed1998

Conjunction dysfunction: CBP/p300 in human disease.

CBP and its homolog p300 are large nuclear molecules that coordinate a variety of transcriptional pathways with chromatin remodeling. They interact with transcriptional activators as well as repressors, direct chromatin-mediated transcription, function in TP53-mediated apoptosis, and participate in terminal differentiation of certain tissue types. Recent evidence suggests that the demand for CBP/p300 is greater than the supply, and that competition for CBP/p300 might play an important role in cell growth regulation. Alterations of the human CBP gene have been implicated in hematological malignancies as well as in congenital malformation and mental retardation. Likewise, the p300 gene has been recently implicated in leukemia and mutations in both alleles have been observed in gastric and colorectal carcinomas. The role of these proteins in human disease coupled with biochemical evidence suggests that CBP and p300 are tumor suppressor proteins essential in cell-cycle control, cellular differentiation and human development.

Animals↗

PubMed1997

Construction of a 1.2-Mb contig surrounding, and molecular analysis of, the human CREB-binding protein (CBP/CREBBP) gene on chromosome 16p13.3.

In the interest of cloning and analyzing the genes responsible for two very different diseases, the Rubinstein-Taybi syndrome (RTS) and acute myeloid leukemia (AML) associated with the somatic translocation t(8;16)(p11;p13.3), we constructed a high-resolution restriction map of contiguous cosmids (contig) covering 1.2 Mb of chromosome 16p13.3. By fluorescence in situ hybridization and Southern blot analysis, we assigned all tested RTS and t(8;16) translocation breakpoints to a 100-kb region. We have previously reported exact physical locations of these 16p breakpoints, which all disrupt one gene we mapped to this interval: the CREB-binding protein (CBP or CREBBP) gene. Intriguingly, mutations in the CBP gene are responsible for RTS as well as the t(8;16)-associated AML. CBP functions as an integrator in the assembly of various multiprotein regulatory complexes and is thus necessary for transcription in a broad range of transduction pathways. We report here the cloning, physical mapping, characterization, and full cDNA nucleotide sequence of the human CBP gene.

Amino Acid Sequence↗

PubMed1997

The history of physical medicine and rehabilitation as recorded in the diary of Dr. Frank Krusen: Part 3. Consolidating the position (1948-1953)

This article is a continuation of the story of the struggle to win recognition of physical medicine and rehabilitation as a medical specialty, as told in the pages of a daily diary kept by Frank H. Krusen, MD, from 1943 through 1967. The first two articles described Dr. Krusen's professional development before 1943, his efforts to establish a certifying Board for physiatrists, and the role of the Baruch Committee on Physical Medicine in Krusen's eventual successes. This article focuses on how Krusen and his physiatric colleagues campaigned to gain acceptance by organized medicine of the new specialty, to unite the fields of physical medicine and rehabilitation, and to identify and maintain the scope of physiatric practice despite challenges from other specialties.

History, 20th Century↗

PubMed1997

The history of physical medicine and rehabilitation as recorded in the diary of Dr. Frank Krusen: Part 4. Triumph over adversity (1954-1969).

This article, the last of four based on the diary of Dr. Frank H. Krusen, picks up the story of physiatry's conflict with other medical specialty groups within the American Medical Association. The conflict was focused on PM&R's use of the term "rehabilitation," but the underlying motive of groups opposing physical medicine was to limit the scope of physiatric practice. Dr. Krusen organized a well-documented and successful defense of the specialty and opened the door to the development of comprehensive care of persons with disabilities. Also related here are Dr. Krusen's legislative and public relations contributions to PM&R from 1963 until his retirement from Tufts-New England Medical Center in 1969. Dr. Krusen retired to Cape Cod and died there in 1973.

History, 20th Century↗

PubMed1997

The history of physical medicine and rehabilitation as recorded in the diary of Dr. Frank Krusen: Part 1. Gathering momentum (the years before 1942).

Frank H. Krusen, MD, was arguably the most influential member of the small group of physicians who began in 1938 a long and difficult struggle to win acceptance of physical medicine and rehabilitation as a medical specialty. The struggle was aided immeasurably in 1943 when a millionaire philanthropist, M. Bernard Baruch, financed the establishment of the Baruch Committee on Physical Medicine. Dr. Krusen became the Director-Secretary of the Committee and began to keep a daily diary in which he recorded his activities and those of his colleagues in their quest for recognition of PM&R as a specialized field of medical practice. That recognition came in 1947 with the establishment of the American Board of Physical Medicine, but Dr. Krusen continued his diary through 1967. In 1988, 15 years after his death, Dr. Krusen's family donated a copy of the diary to the History of Medicine Library of the Mayo Clinic in Rochester, MN. The gift coincided with the American Academy of Physical Medicine and Rehabilitation's celebration of its 50th anniversary. This article, the first of four, introduces the reader to Dr. Krusen and describes his early years and his professional development in the years before 1943.

History, 20th Century↗

PubMed1997

The history of physical medicine and rehabilitation as recorded in the diary of Dr. Frank Krusen: Part 2. Forging ahead (1943-1947).

Presented here is a continuation of the story--as drawn from the diary entries of Frank. H. Krusen. MD--of the struggle to gain recognition for, and acceptance of, physical medicine as a medical specialty in its own right. It details the events, as described by physical medicine's strongest protagonist, between 1943 and 1947 that led finally to the establishment of the American Board of Physical Medicine. The millionaire philanthropist Bernard Baruch provided the financial resources that were required to establish academic and clinical programs in the field of physical medicine. Dr. Krusen was a key member of the Baruch Committee on Physical Medicine, which provided over sight for the newly created programs. His thoughts and sentiments concerning his role in the struggle, as he recorded them in his diary, are reported here.

History, 20th Century↗

PubMed1997

Differential effects of deoxycholic acid on proliferation of neoplastic and differentiated colonocytes in vitro.

The secondary bile acid deoxycholic acid is believed to be a promoter of large bowel cancer, in part by inducing colonic epithelial proliferation. The effects of deoxycholic acid on [3H]thymidine incorporation by the human colon cancer cell line HT29 and two differentiated subclones were measured and compared. The subclone HT29-C1 has features of mature absorptive cells and HT29-N2 cells secrete mucus under cholinergic control. The three cell lines were treated with deoxycholic acid (DCA) at concentrations of 0, 5, 10, 50, 100, 150, and 300 microM for 3, 6, 9, 15, 24, and 48 hr. A significant increase in proliferation was noted in HT29 cells only at 6 hr with 5 and 10 microM deoxycholic acid. Neither the subclone HT29-C1, nor HT29-N2 cells exhibited significant change in [3H]thymidine incorporation with DCA at these concentrations or time points. Higher doses of deoxycholic acid above 50 microM and duration of exposure greater than 24 hr were cytotoxic to all three cell lines. The proliferative effects of DCA in HT29 cells were not paralleled by changes in protein kinase C activity or protein kinase C isoform expression. Quantitative and qualitative differences in PKC isoform expression were not noted in the three cell lines used in this study. The proliferative effects of DCA on HT29 cells appear to be independent of the PKC signal transduction pathway.

Blotting, Western↗