Biomedical subjects

B Bornstein

Publications and source records attributed to B Bornstein.

At least 19 recordsLinked to original sources

PubMed2003

Mutation analysis in 16 patients with mtDNA depletion.

Sixteen unrelated Southern European patients with the mitochondrial depletion syndrome (MDS) were analyzed for mutations in the TK2 and DGUOK genes. Three novel mutations were identified in TK2 (R183G, R254X, and 142insG). When we analyzed additional genes involved in the dNTPs pool, such as SLC25A19 (DNC) and NT5M (d-NT2), we did not detect mutations. The current study suggest that scanning the TK2, DGUOK, SLC25A19, and NT5M genes is likely to help about 10% of MDS families in terms of genetic counseling. Also, our findings indicate that genotype-phenotype correlations are not straightforward in MDS.

Age of Onset↗

PubMed2001

Relationship of angiotensin converting enzyme genotype with serum triglyceride concentration in stroke patients.

The Objective of this research was to study the relationship of angiotensin converting enzyme (ACE) genotype with serum triglycerides concentration in stroke patients. The insertion/deletion (I/D) ACE polymorphism was identified by using polymerase chain reaction in 122 prospectively studied ischemic stroke patients (age 45-91 years). Serum triglycerides concentration was determined at admission and 3 months after the stroke, and compared between the ACE genotype groups (37 D/D, 68 D/I, 17 I/I). All clinical characteristics were similar in the three groups. Patients with D/D genotype had mean serum triglycerides concentration significantly higher in acute (179.0+/-111.8 mg/dl) and chronic phase (176.4+/-121.6 mg/dl) than those with I/I genotype (acute phase: 108.7+/-36.1 mg/dl, P=0.019; chronic phase: 116.0+/-44.3 mg/dl, P=0.021). The results showed that serum triglycerides concentration is elevated in stroke patients with the DD ACE genotype and it may be related to the risk of cerebrovascular disease associated with this polymorphism.

Acute Disease↗

PubMed2001

Mitochondrial dysfunction associated with a mutation in the Notch3 gene in a CADASIL family.

BACKGROUND: Cerebral autosomal arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is characterized by recurrent subcortical ischemic strokes and dementia caused by mutations in the Notch3 gene. In Drosophila melanogaster, Notch signaling has a pleiotropic effect, affecting most tissues of the organism during development. OBJECTIVE: To characterize a potential mitochondrial dysfunction associated with mutations in the Notch3 gene. METHODS: Biochemical, histochemical, molecular, and genetic analyses were performed on muscle biopsy specimens and fibroblasts obtained from patients of a Spanish family with CADASIL. Additional biochemical and molecular analyses of the N(55e11) mutant of D. melanogaster were performed. RESULTS: In muscle biopsy specimens, a significant decrease was found in the activity of complex I (NADH [reduced form of nicotinamide adenine dinucleotide] dehydrogenase), and in one patient, histochemical analysis showed the presence of ragged-red fibers with abnormal cytochrome c oxidase staining. Reduced fibroblast activity of complex V (ATP synthase) was found. Supporting data on patients with CADASIL, it was found that the mutation N(55e11) in Drosophila decreases the activity of mitochondrial respiratory complexes I and V. CONCLUSIONS: Mitochondrial respiratory chain activity responds, directly or indirectly, to the Notch signaling pathway. Mitochondrial dysfunction in patients with CADASIL may be an epiphenomenon, but results of this study suggest that the pathophysiology of the disease could include a defect in oxidative phosphorylation.

Adult↗

PubMed2001

Early-onset multisystem mitochondrial disorder caused by a nonsense mutation in the mitochondrial DNA cytochrome C oxidase II gene.

We report the first nonsense mutation (G7896A) in the mtDNA gene for subunit II of cytochrome c oxidase (COX) in a patient with early-onset multisystem disease and COX deficiency in muscle. The mutation was heteroplasmic in muscle, blood, and fibroblasts from the patient and abundantly present in COX-deficient fibers, but less abundant in COX-positive fibers; it was not found in blood samples from the patient's asymptomatic maternal relatives. Immunoblot analysis showed a reduced concentration of both COX II and COX I polypeptides, suggesting impaired assembly of COX holoenzyme.

Child, Preschool↗

PubMed2001

The effects of limiting punitive damage awards.

In response to concerns that jury awards in tort cases are excessive and unpredictable, nearly every state legislature has enacted some version of tort reform that is intended to curb extravagant damage awards. One of the most important and controversial reforms involves capping (or limiting) the maximum punitive damage award. We conducted a jury analogue study to assess the impact of this reform. In particular, we examined the possibility that capping punitive awards would cause jurors to inflate their compensatory awards to satisfy their desires to punish the defendant, particularly in situations where the defendant's conduct was highly reprehensible. Relative to a condition in which punitive damages were unlimited, caps on punitive damages did not result in inflation of compensatory awards. However, jurors who had no option to award punitive damages assessed compensatory damages at a significantly higher level than did jurors who had the opportunity to do so. We discuss the policy implications of these findings.

Adult↗

PubMed2000

Reduction of cardiac volume in left-breast treatment fields by respiratory maneuvers: a CT study.

PURPOSE: A previous study of healthy female volunteers suggested that deep inspiratory breath holding can reduce the cardiac volume in the treatment portals for left-breast cancer treatment. The reduction of irradiated cardiac volume may be important considering the reported late cardiac morbidity and mortality and the frequent coexistent use of potentially cardiotoxic chemotherapy in breast cancer patients. In the present study, we evaluated the heart volume in the fields and, thus, the true benefit of this respiratory maneuver in breast cancer patients undergoing CT simulation. MATERIALS AND METHODS: Fifteen patients (median age, 53) were studied. For each patient, CT scans were performed both when the patient breathed normally (quiet respiration) and when the patient held her breath after a deep inspiration. Tangential fields were planned using the same medial, lateral, superior, and inferior borders on skin for the normal breathing and the breath-holding configurations. The cardiac and left-lung volumes within the tangential fields were calculated for both breathing configurations. Multiple scan series were performed for the breath-holding configuration to provide a more accurate delineation of the cardiac tissue and to study the reproducibility of the patient's position between different cycles of deep inspiration. RESULTS: None of the patients had difficulty holding her breath for 20 s. The cardiac volume in the field was reduced (-86 +/- 24%; p < 0.001) when patients held their breath after a deep inspiration compared to when breathing normally. For 7 patients (47%), deep inspiration moved the heart completely out of the radiation fields. The expansion of the lung tissue due to deep inspiration also increased the absolute lung volume in the tangential fields (183 cm(3) vs 97 cm(3), p < 0.001). However, the fractional volume of the left lung in the field was essentially unchanged. For all but 1 patient, the maximum difference between the external body contours from different breath holding cycles was 5 mm and occurred at the lateral aspect of the breast. At the medial aspect, as indicated by the position of the midline marker, the variations were well within the currently accepted tolerance for patient positioning during tangential treatment. CONCLUSIONS: Deep-inspiration breath holding substantially reduces cardiac volume in the tangential fields for left-sided breast cancer treatment. The variation between patient positions at different cycles of breath holding was found to be reasonably small. Therefore, it appears feasible to reduce cardiac radiation by treating patients with intratreatment minifractions lasting 10-15 s while patients hold their breath.

Aged↗

PubMed2000

The relation between the presence and extent of lobular carcinoma in situ and the risk of local recurrence for patients with infiltrating carcinoma of the breast treated with conservative surgery and radiation therapy.

BACKGROUND: When found in an otherwise benign biopsy, lobular carcinoma in situ (LCIS) has been associated with an increased risk of development of a subsequent invasive breast carcinoma. However, the association between LCIS and the risk of subsequent local recurrence in patients with infiltrating carcinoma treated with conservative surgery and radiation therapy has received relatively little attention. METHODS: Between 1968 and 1986, 1625 patients with clinical Stage I-II invasive breast carcinoma were treated at the Joint Center for Radiation Therapy at Harvard Medical School with breast-conserving surgery (CS) and radiation therapy (RT) to a total dose to the primary site of > or =60 grays. Analysis was limited to 1181 patients with infiltrating ductal carcinoma, infiltrating lobular carcinoma, or infiltrating carcinoma with mixed ductal and lobular features who, on review of their histologic slides, had sufficient normal tissue adjacent to the tumor to evaluate for the presence of LCIS and also had a minimum potential follow-up time of 8 years. The median follow-up time was 161 months. RESULTS: One hundred thirty-seven patients (12%) had LCIS either within the tumor or in the macroscopically normal adjacent tissue. The 8-year crude risk of recurrence was not significantly increased for patients with LCIS associated with invasive ductal, invasive lobular, or mixed ductal and lobular carcinoma. Among the 119 patients with associated LCIS adjacent to the tumor, the 8-year rate of local recurrence was 13%, compared with 12% for the 1062 patients without associated LCIS. For the 70 patients with moderate or marked LCIS adjacent to the tumor, the 8-year rate of local recurrence was 13%. The extent of LCIS did not affect the risk of recurrence. The risks of contralateral disease and of distant failure were similarly not affected by the presence or extent of LCIS. CONCLUSIONS: Breast-conserving therapy involving limited surgery and radiation therapy is an appropriate method of treating patients with invasive breast carcinoma with or without associated LCIS. Neither the presence nor the extent of LCIS should influence management decisions regarding patients with invasive breast carcinoma. [See editorial counterpoint and reply to counterpoint on pages 978-81 and 982-3, this issue.]

Breast Neoplasms↗

PubMed2000

The pathogenic role of point mutations affecting the translational initiation codon of mitochondrial genes.

The mutation T3308C results in a Met --> Thr change at the highly conserved amino acid position 1 of the mtDNA ND1 gene (M1T). To study its potential pathogenic effect we have carried out a combination of mitochondrial protein synthesis and Northern and Western analyses. Our data demonstrate that M1T mutation does not affect the efficiency of the synthesis of the ND1 polypeptide and suggest that any codon specifying methionine located close to the 5' end of mitochondrial mRNAs may be used as translational initiator.

Blotting, Northern↗

PubMed2000

The pathophysiology of mitochondrial biogenesis: towards four decades of mitochondrial DNA research.

Mitochondria are with very few exceptions ubiquitous organelles in eukaryotic cells where they are essential for cell life and death. Mitochondria play a central role not only in a variety of metabolic pathways including the supply of the bulk of cellular ATP through oxidative phosphorylation (OXPHOS), but also in complex processes such as development, apoptosis, and aging. Mitochondria contain their own genome that is replicated and expressed within the organelle. It encodes 13 polypeptides all of them components of the OXPHOS system, and thus, the integrity of the mitochondrial DNA (mtDNA) is critical for cellular energy supply. In the past 12 years more than 50 point mutations and around 100 rearrangements in the mtDNA have been associated with human diseases. Also in recent years, several mutations in nuclear genes that encode structural or regulatory factors of the OXPHOS system or the mtDNA metabolism have been described. The development of increasingly powerful techniques and the use of cellular and animal models are opening new avenues in the study of mitochondrial medicine. The detailed molecular characterization of the effects produced by different mutations that cause mitochondrial cytopathies will be critical for designing rational therapeutic strategies for this group of devastating diseases.

Animals↗

PubMed1999

Structure and regulated expression of the delta-aminolevulinate synthase gene from Drosophila melanogaster.

The structure of the single copy gene encoding the putative housekeeping isoform of Drosophila melanogaster delta-aminolevulinate synthase (ALAS) has been determined. Southern and immunoblot analyses suggest that only the housekeeping isoform of the enzyme exists in Drosophila. We have localized a critical region for promoter activity to a sequence of 121 base pairs that contains a motif that is potentially recognized by factors of the nuclear respiratory factor-1 (NRF-1)/P3A2 family, flanked by two AP4 sites. Heme inhibits the expression of the gene by blocking the interaction of putative regulatory proteins to its 5' proximal region, a mechanism different from those proposed for other hemin-regulated promoters. Northern and in situ RNA hybridization experiments show that maternal alas mRNA is stored in the egg; its steady-state level decreases rapidly during the first hours of development and increases again after gastrulation in a period where the synthesis of several mRNAs encoding metabolic enzymes is activated. In the syncytial blastoderm, the alas mRNA is ubiquitously distributed and decreases in abundance substantially through cellular blastoderm. Late in embryonic development alas shows a specific pattern of expression, with an elevated mRNA level in oenocytes, suggesting an important role of these cells in the biosynthesis of hemoproteins in Drosophila.

5-Aminolevulinate Synthetase↗

PubMed1999

A double mutation (A8296G and G8363A) in the mitochondrial DNA tRNA (Lys) gene associated with myoclonus epilepsy with ragged-red fibers.

OBJECTIVE: To define potential pathogenic mitochondrial DNA (mtDNA) point mutations in a patient with myoclonus epilepsy with ragged-red fibers (MERRF) syndrome. BACKGROUND: MERRF syndrome is typically associated with point mutations in the mtDNA tRNALys gene. METHODS: We performed morphologic, biochemical, and genetic analysis of muscle samples from the patient and four relatives. Molecular genetic studies included sequencing, PCR, and restriction enzyme analysis on whole muscle, blood, and single muscle fibers. RESULTS: Muscle biopsy showed cytochrome c oxidase (COX), negative ragged-red fibers (RRF), and a defect of complex I of the mitochondrial respiratory chain. We found an A8296G transition and a G8363A mutation in the mtDNA tRNALYs gene. The A8296G was almost homoplasmic in muscle and blood from the propositus and his oligosymptomatic maternal relatives. The G8363A mutation was heteroplasmic and more abundant in muscle than in blood, and its proportion correlated with clinical severity. Single muscle fiber analysis showed significantly higher levels of G8363A genomes in COX-negative than in normal fibers, and almost homoplasmic levels of mutant A8296G mtDNA in both COX-negative and normal fibers. The two mutations affect highly conserved nucleotides and were not found in controls. CONCLUSIONS: The G8363A mutation is pathogenic; the co-occurrence of the A8296G mutation is of unclear significance and is likely to be a rare polymorphism.

Adult↗

PubMed1998

Mitochondrial gene expression and respiratory enzyme activities in cardiac diseases.

Respiratory enzyme activities and steady-state level of two mitochondrial-encoded transcripts were quantified in heart muscle biopsies from patients suffering various types of cardiomyopathies unrelated to mitochondrial primary disorders. We have found that although the mitochondrial DNA copy number and the concentration of COI and ND4 transcripts remain fairly constant, there is an important increase (up to 6-fold) in respiratory enzyme activities affecting to several oxidative phosphorylation complexes. Idiopathic dilated cardiomyopathy shows the greatest increase, followed by ischemic heart and ventricular hypertrophy due to aortic stenosis. The results suggest an energetic compensatory mechanism in the heart muscle, in the absence of mitochondrial proliferation or activation of mitochondrial gene expression.

DNA, Mitochondrial↗

PubMed1998

Effects of L-carnitine on erythrocyte acyl-CoA, free CoA, and glycerophospholipid acyltransferase in uremia.

We studied the effects of L-carnitine treatment in the acyl flux of erythrocyte membranes from uremic patients. We found a significantly lower relative proportion of long-chain acyl-CoA (LCCoA) to free CoA (FCoA) in patients than in control subjects. In addition, patients had reduced activities of both carnitine palmitoyltransferase (CPT) and glycerophospholipid acyltransferase (LAT; CoA dependent), and increased ratios of long-chain acylcarnitine (LCAC) to free carnitine in their erythrocytes. These data support the hypothesis that acyl-trafficking is altered in erythrocytes in uremia. After treatment with L-carnitine, we observed a significant increase in CPT and LAT activities as well as in the LCCoA-FCoA ratio, and a significant decrease in the ratio of LCAC to free carnitine. These results support the conclusion that L-carnitine supplementation improves erythrocyte flux in uremic patients.

Acyl Coenzyme A↗

PubMed1998

No long-term increase in cardiac-related mortality after breast-conserving surgery and radiation therapy using modern techniques.

PURPOSE: To determine whether left-breast irradiation using modern techniques after breast-conserving surgery leads to an increased risk of cardiac-related mortality. METHODS: Between 1968 and 1986, 1,624 patients were treated for unilateral stage I or II breast cancer at the Joint Center for Radiation Therapy, Harvard Medical School, Boston, MA, with conservative surgery and breast irradiation. Seven hundred forty-five patients with a potential follow-up of at least 12 years were analyzed. Clinical, pathologic, and treatment characteristics were compared between the 365 patients (49%) who received left-sided irradiation and the 380 patients (51%) who received right-sided irradiation. The relationship between left-sided breast irradiation and the risk of nonbreast cancer- and cardiac-related mortality was examined. RESULTS: There was no significant difference in the distribution of clinical, pathologic, or treatment characteristics between the two groups, with the exception of a small difference in pathologic tumor size (medians, left, 2.0 cm, right, 1.5 cm; P = .007). At 12 years, a majority of patients still were alive. Slightly more patients with left-sided tumors had died of breast cancer (31% v 27%; P = NS). Equivalent proportions from each group died of nonbreast cancer causes (11%), including nine patients (2%) from each group who died from cardiac causes. The risk of cardiac mortality did not increase as time after treatment increased for patients who received left-sided irradiation compared with right-sided irradiation. A model that controlled for clinical, pathologic, and treatment differences showed no significant increase in any category of cause of death (breast, cardiac, or other) for patients who received left-sided irradiation. CONCLUSION: These results suggest that modern breast radiotherapy is not associated with an increased risk of cardiac-related mortality within at least the first 12 years after treatment.

Breast Neoplasms↗

PubMed1998

Family history and treatment outcome in young women after breast-conserving surgery and radiation therapy for early-stage breast cancer.

PURPOSE: To evaluate the safety and efficacy of breast-conserving therapy for young women with a family history (FH) suggestive of inherited breast cancer susceptibility. MATERIALS AND METHODS: A total of 201 patients aged 36 or younger at diagnosis treated with breast-conserving surgery and radiation therapy (> or = 60 Gy) for early-stage breast cancer were categorized by FH. FH was considered positive in 29 patients who, at the time of diagnosis, had a mother or sister previously diagnosed with breast cancer before age 50 or ovarian cancer at any age. Clinical, pathologic, and demographic variables; sites of first failure; disease-free survival; and overall survival (OS) were compared between FH-positive and -negative groups. Median follow-up time was 11 years. RESULTS: Patient and tumor features were similar between those with and without an FH. Regression analysis of sites of first failure at 5 years demonstrated a risk ratio (RR) of 5.7 for opposite breast cancer for FH-positive patients. Rates of local, regional, and distant failure and disease-free survival or OS did not differ between FH-positive and -negative patients. Age at diagnosis and Ashkenazi heritage were not significantly predictors of patterns of failure. CONCLUSION: Breast-conserving surgery combined with radiation therapy is not associated with a higher rate of local recurrence, distant failure, or second (non-breast) cancers in young women with an FH suggestive of inherited breast cancer susceptibility compared with young women without an FH. However, their increased risk of opposite breast cancer should be taken into account when considering breast conservation as a treatment option.

Adult↗

PubMed1998

[Human mitochondrial genetic system].

The mitochondria are subcellular organelles devoted to energy production in form of ATP that contain their own genetic system. Mitochondrial DNA codify a small, but extremely important, number of polypeptides of the respiratory chain. The other mitochondrial proteins are encoded in the nucleus. Therefore, mitochondrial biogenesis require the coordinated expression of nuclear and mitochondrial genetic systems. The gene arrangement in mitochondrial DNA is extremely compact with the tRNA genes interspersed with the rRNA and protein-coding genes. This organization has its precise counterpart in the mode of expression and distinctive structural features of the RNAs. Both mitochondrial DNA strands are transcribed as a whole in the form of three polycistronic molecules that are later cut by specific enzymes that recognize the 5' and 3' end of the tRNA sequences, to produced the mature rRNA, mRNA and tRNA. The mitochondrial coded mRNAs are translated into proteins by a mitochondrial specific protein-synthesizing machinery. The genetics of the mitochondrial DNA differs from that of the nuclear DNA in several features. In particular, the mitochondrial genome is inherited from the mother that transmit their mitochondrial DNA to all her offsprings. Another characteristic of this genome is its tendency to mutate more frequently than the nuclear DNA. This provides a powerful tool for studying the evolution of man.

DNA, Mitochondrial↗

PubMed1998

[Studies of pathogenicity and characterization of molecular phenotype caused by mutations in human mitochondrial DNA].

Mitochondrial DNA evolves and accumulates mutations more rapidly than nuclear DNA. These nucleotide variation may produce neutral polymorphisms or affect to functional conserved positions being very deleterious. On the other hand the relation between the type of mutation (genotype) and the observed clinical symptoms (phenotype) is nowadays practically unknown. Therefore it is very important to demonstrate clearly that the new described mutations are pathogenic and understanding the molecular mechanisms responsible for the energetic metabolism dysfunction produced by these mutations at cellular level. In the last years several procedures have been developed, including in situ hybridization, single-fiber PCR and the use of patient myoblast, fibroblast and lymphoblast cell culture lines. Specially relevant is the cybrid technology that allow repopulate a cell line depleted of mtDNA with mitochondria obtained from patient fibroblasts, producing transmitochondrial cell lines. The use of these methodology in the last few years has been very important to understand the pathogenic mechanism of some of the classical mutations associated to mitochondrial pathology.

Bone Neoplasms↗

PubMed1997

Locally advanced rectal carcinoma: pelvic control and morbidity following preoperative radiation therapy, resection, and intraoperative radiation therapy.

PURPOSE: To determine the impact of intraoperative radiation therapy (IORT) combined with preoperative external beam irradiation and surgical resection in patients with locally advanced, unresectable rectal carcinoma. METHODS AND MATERIALS: Between 1982 and 1993, 40 patients with locally advanced colorectal cancer unresectable at initial presentation were treated with preoperative external beam radiation therapy (median dose 50.4 Gy). Thirty patients received concurrent 5-fluorouracil. Twenty-seven patients had primary tumors and 13 had recurrent disease; 1 patient had a solitary hepatic metastasis at the time of surgery. Four to 6 weeks after radiation, surgical resection was undertaken, and if microscopic or gross residual disease was encountered, IORT was delivered to the tumor bed. Patients with an unevaluable or high-risk margin were also considered for IORT. IORT was delivered through a dedicated 300-kVp orthovoltage unit. The median dose of IORT was 12.5 Gy (range 8-20). The dose was typically prescribed to a depth of 1-2 cm. The median follow-up was 33 months (range 5-100). RESULTS: Thirty-three patients were able to undergo a curative resection (83%). Five patients had gross residual disease despite aggressive surgery. Seven patients did not receive IORT: six because of clear margins, and one with gross disease that could not be treated for technical reasons. The remainder of the patients (26) received IORT to the site of pelvic adherence. The crude local control rates for patients following complete resection with negative margins were 92% for patients treated with IORT and 33% for patients without IORT. IORT was ineffective for gross residual disease. Pelvic control was none of four in this setting. The crude local control rate of patients with primary cancer was 73% (16 of 22), as opposed to 27% (3 of 11) for these with recurrent cancer. The 5-year actuarial overall survival and local control rates for patients undergoing gross complete resection and IORT were 64% and 75%, respectively. Seventeen of the 26 patients (65%) who received IORT experienced pelvic complications, as opposed to two patients (28%) who did not receive IORT. The incidence of complications was similar in the patients with primary versus recurrent disease. All cases were successfully treated with the placement of a posterior thigh myocutaneous flap. Of note, no pelvic osteoradionecrosis was seen in this series. CONCLUSION: Patients with locally advanced carcinoma of the rectum were aggressively treated with combined modality therapy consisting of preoperative external beam radiotherapy, surgery, and IORT. The pelvic control rate was 82% for patients with minimal residual disease. IORT failed to control gross residual disease. The incidence of pelvic wound healing problems was 65% in this series; however, a reconstructive procedure which replaced irradiated tissue with a vascularized myocutaneous flap was successful in treating this complication. We believe that IORT has therapeutic merit in the treatment of locally advanced rectal cancer, particularly in the setting of minimal residual disease.

Adult↗