MRI to assess response after neoadjuvant chemotherapy in breast cancer subtypes: a systematic review and meta-analysis.

This meta-analysis aimed to estimate and compare sensitivity, specificity, positive- (PPV) and negative predictive value (NPV) of magnetic resonance imaging (MRI) for predicting pathological complete remission (pCR) after neoadjuvant chemotherapy (NAC) in patients with early-stage breast cancer. We stratified for molecular subtype by immunohistochemistry (IHC) and explored the impact of other factors. Two researchers systematically searched PUBMED and EMBASE to select relevant studies and extract data. For meta-analysis of sensitivity and specificity, we used bivariate random-effects models. Twenty-six included studies contained 4497 patients. There was a significant impact of IHC subtype on post-NAC MRI accuracy (p = 0.0082) for pCR. The pooled sensitivity was 0.67 [95% CI 0.58-0.74] for the HR-/HER2-, 0.65 [95% CI 0.56-0.73] for the HR-/HER2+, 0.55 [95% CI 0.45-0.64] for the HR+/HER2- and 0.60 [95% CI 0.50-0.70] for the HR+/HER2+ subtype. The pooled specificity was 0.85 [95% CI 0.81-0.88] for the HR-/HER2-, 0.81 [95% CI 0.74-0.86] for the HR-/HER2+, 0.88[95% CI 0.84-0.91] for the HR+/HER2- and 0.74 [95% CI 0.63-0.83] for the HR+/HER2+ subtype. The PPV was highest in the HR-/HER2- subtype and lowest in the HR+/HER2- subtype. MRI field strength of 3.0 T was associated with a higher sensitivity compared to 1.5 T (p = 0.00063). The accuracy of MRI for predicting pCR depends on molecular subtype, which should be taken into account in clinical practice. Higher MRI field strength positively impacts accuracy. When intervention trials based on MRI response evaluation are designed, the impact of IHC subtype and field strength on MR accuracy should be considered.

The inverted terminal repetition of the DNA of weakly oncogenic adenovirus type 7.

By use of the chemical modification technique of Maxam and Gilbert (1977), the first 180 base pairs at both termini of the human adenovirus 7 genome have been determined. The results show that adenovirus 7 DNA contains a perfect inverted terminal repetition of 136 base pairs.

The nucleotide sequence of fragment HindIII-C of human adenovirus type 5 DNA (map positions 17.1-31.7).

This paper describes the sequence of nucleotides 6246-11570 between the two HindIII sites at map positions (m.p.) 17.1 and 31.7 of human adenovirus serotype 5 (Ad5) DNA. It is 99% homologous with the corresponding HindIII-B fragment of adenovirus type 2 (Ad2; Gingeras et al., 1982; Aleström et al., 1982) which has been shown to encode the second, "i", and third leaders of the major late RNAs, the virus-associated RNAs VAI and VAII (all rightward transcripts), and in the opposite sense the early-region E2b mRNAs for a DNA polymerase and for the terminal protein precursor (pTP). Except for the latter, it was possible to determine the coordinates of the corresponding Ad5 RNAs, either by sequence homology with Ad2, or by nuclease S1 analysis. The Ad5 DNA sequence contains the same open reading frames as that of Ad2. The longest of these lie in the r-strand and would specify proteins of Mr 120377 (DNA polymerase) and 74558 (pTP).

Gene organization of the transforming region of adenovirus type 7 DNA.

The sequence of the leftmost 11% of the weakly oncogenic human adenovirus type 7 (Ad7) DNA has been determined. This part of the Ad7 viral genome encompasses early region E1 which has been shown to be involved in the process of cell transformation in vitro (Dijkema et al., 1979). From the nucleotide sequence and determined coordinates of the E1 mRNAs, we are able to predict the primary structure of the polypeptides encoded by the transforming region of Ad7. The organization of the E1 region of Ad7 and of other adenovirus serotypes (Bos et al. 1981) leads to the proposal of a novel mechanism for gene regulation at the translational level in which protein synthesis can initiate at either the first or the second AUG triplet available in mRNA. The differences between the large E1b-specific tumor antigens of adenovirus types 12, 7 and 5 may explain the differences in oncogenicity of these viruses.

The nucleotide sequence of the transforming BglII-H fragment of adenovirus type 7 DNA.

The nucleotide sequence of the leftmost BglII-H fragment (0--4.5%) of weakly oncogenic human adenovirus serotype 7 (Ad7) has been determined (1568 base pairs). This is the shortest Ad7 DNA fragment reported to transform primary rat cells into an immortal cell line (Dijkema et al., 1979). The l-strand of BhlII-H was found to contain the complete information for a polypeptide of at most 28 051 daltons, followed by the putative promoter site of the next gene. Comparison of the determined Ad7 sequence with that of the corresponding region of non-oncogenic Ad5 (Van Ormondt et al., 1978; Maat and Van Ormondt, 1979) showed that the over-all organization of the two DNAs is quite similar, but that the sequences, except in regions of suspected strategic importance, diverge considerably.

Cloning of the natural gene for the sweet-tasting plant protein thaumatin.

Five different clones, homologous to the structural gene for the sweet-tasting plant protein thaumatin, have been isolated from leaf DNA of Thaumatococcus daniellii Benth. Restriction maps, hybridization studies, S1-nuclease mapping and R-loop formation revealed that the thaumatin genes isolated belong to one multigene family, and have two very small introns situated at different positions in the various structural genes. A similar situation prevails in a number of seed storage genes. This suggests a similarity between the sweet-tasting protein thaumatin and seed storage proteins.

The gene for polypeptide IX of human adenovirus type 7.

This paper describes the nucleotide sequence of subgroup B human adenovirus type 7 (Ad7) between positions 3351-4010, and of cloned cDNA derived from mRNAs encoded by this segment. One of these (mRNA VII) is shown to be unspliced, and has its 5'- and 3'-ends encoded by positions 3460 (determined by the nuclease S1 technique) and 3939, respectively. The mRNA sequence contains a single open reading frame for protein biosynthesis between the first available initiation triplet AUG at position 3481 to the stop codon UAA at position 3895. It can specify a polypeptide of 138 amino acids (14 098 daltons) which must be polypeptide IX of Ad7, as is evident from its mapping position, and from a comparison with the sequence of the protein IX gene of subgroup C adenovirus type 5.

The nucleotide sequence of the gene for protein IVa2 and of the 5' leader segment of the major late mRNAs of adenovirus type 5.

We present here the primary structure of the region of human adenovirus 5 (Ad5) DNA from nucleotide 4001 through the HindIII site at nucleotide 6246 (map positions 0.11 to 0.17). The corresponding region in the closely related adenovirus type 2 (Ad2) encodes the spliced mRNA for viral protein IVa2 (Chow et al., 1979; Persson et al., 1979). Reverse transcription of the Ad5 pIVa2 mRNA localized the 5' terminus of the mRNA to approximately position 5840, and its splice coordinates to positions 5706 and 5427. From the data of Aleström et al. (1980) for Ad2, the 3' end of this mRNA was inferred to be specified by Ad5 nucleotide 4060. The nucleic acid data allow us to predict an Mr of 50873 for the IVa2 protein of Ad5, which is close to the experimentally determined value of 50000 (Persson et al., 1979). The DNA sequence described here also includes the information for the 5'-terminal leader segment of the major late mRNAs of Ad5.

Gene organization of the transforming region of weakly oncogenic adenovirus type 7: the E1a region.

The structures of adenovirus type 7 (Ad7) cytoplasmic RNAs transcribed from the leftmost 4.5% of the viral genome during lytic infection of KB cells have been determined. The E1a region was found to specify three differently spliced mRNAs (I, II and III) which have common 5' and 3' termini. mRNAs I and II are transcribed between identical initiation and termination codons and code for polypeptides of 28 kd and 24 kd, whose only difference is an internal sequence of 32 amino acids present in the 28-kd protein. Translation of mRNA III initiates at the same AUG codon as in mRNA I and II, but uses a different reading frame beyond the splice point; consequently, it terminates at an earlier stop codon and yields a 6.3-kd polypeptide. Cytoplasmic E1a RNA was used as a template for in vitro protein synthesis in a cell-free system and found to encode polypeptides with apparent molecular weights of 42 kd, 40 kd, and 11 kd.

Production of correctly processed human serum albumin in transgenic plants.

We have used a modified CaMV 35S promoter to direct the expression of chimaeric genes encoding human serum albumin (HSA) in transgenic potato and tobacco plants. To secrete the protein, either the human prepro-sequence or the signal sequence from the extracellular tobacco protein PR-S was used. We demonstrate secretion of HSA with both types of signal sequences in transgenic leaf tissue and in suspension cultures. HSA produced in transgenic potato plants was purified to chromatographic homogeneity. N-terminal amino acid sequence analysis revealed that the processing of the precursor protein was dependent on the type of signal sequence. Expression of the human preproHSA gene lead to partial processing of the precursor and secretion of proHSA. Fusion of HSA to the plant PR-S presequence resulted in cleavage of the presequence at its natural site and secretion of correctly processed HSA that is indistinguishable from the authentic human protein.

A quick method to estimate the T-DNA copy number in transgenic plants at an early stage after transformation, using inverse PCR.

Agrobacterium-mediated transformation of plants is known to result in transgenic plants with a variable number of integrated T-DNA copies. Our aim was to obtain transgenic tobacco plants containing one integrated T-DNA copy per genome. Therefore, a quick method was developed to estimate the T-DNA copy number of young transgenic plantlets within 10 weeks after transformation. Inverse polymerase chain reaction (IPCR) was used to amplify junction fragments, i.e. plant genomic DNA sequences flanking the known T-DNA sequences.

Transformation of primary rat kidney cells by DNA fragments of weakly oncogenic adenoviruses.

Primary cultures of baby rat kidney (BRK) cells were transformed by intact DNA and DNA fragments of weakly oncogenic human adenovirus types 3 and 7. The smallest fragment found to contain transforming activity was the left-terminal 4% endo R.HindIII fragment (for both adenovirus type 3 and 7 DNAs). The efficiency of transformation of this fragment was low, and no permanent cell line could be established. Left-terminal fragments ranging from 84 to 4,5% of the viral genome could all transform BRK cells with the same efficiency as intact viral DNA. A number of adenovirus type 7 DNA fragment-transformed lines were established and were found to contain persistent viral DNA sequences and adenovirus subgroup B-specific T antigen. Consequently, the transforming functions of adenovirus types 3 and 7 are located at the extreme left-hand end of the genome, and the minimum size for a DNA fragment with transforming activity is 1.0 X 10(6) daltons. These results do not rule out the possibility that viral genes located outside the transforming region may also influence transformation.

The nucleotide sequence of the leftmost XhoI fragment (6%) of simian adenovirus SA7P.

The DNA of simian adenovirus SA7P was cloned in pBR322. The nucleotide sequences of the leftmost 2238 bp and the rightmost 188 bp of the viral genome were determined. SA7P DNA has an inverted terminal repeat of 183 bp. The sequence at the left terminus exhibits extensive homology with that of the E1 regions of human adenovirus 5, 7 and 12 DNAs. Based on this homology, the RNA coordinates and coding regions could be deduced. The sequenced SA7P DNA contains the entire E1A and part of the E1B region.

Haemodynamic response to exercise in healthy young and elderly subjects.

Whereas with advancing age, peak heart rate (HR) and cardiac index (CI) are clearly reduced, peak stroke index (SI) may decrease, remain constant or even increase. The aim of this study was to describe the patterns of HR, SI, CI, arteriovenous difference in oxygen concentration (Ca-vO2), mean arterial pressure (MAP), systemic vascular resistance index (SVRI), stroke work index (SWI) and mean systolic ejection rate index (MSERI) in two age groups (A: 20-30 years, n = 20; B: 50-60 years n = 20). After determination of pulmonary function, an incremental bicycle exercise test was performed, with standard, gas-exchange measurements and SI assessment using electrical impedance cardiography. The following age-related changes were found: similar submaximal HR response to exercise in both groups and a higher peak HR in A than in B[185 (SD 9) vs 167 (SD 14) beats.min-1, P < 0.0005]; increase in SI with exercise up to 60-90 W and subsequent stabilization in both groups. As SI decreased towards the end of exercise in B, a higher peak SI was found in A [57.5 (SD 14.0) vs 43.6 (SD 7.7) ml.m-2, P < 0.0005]; similar submaximal CI response-to exercise, higher peak CI in A [10.6 (SD 2.5) vs 7.2 (SD 1.3) 1.min-1.m-2, P < 0.0005]; no differences in Ca-vO2 during exercise; higher MAP at all levels of exercise in B; higher SVRI at all levels of exercise in B; lower SWI in B after recovery; higher MSERI at all levels of exercise in A. The decrease in SI with advancing age would seem to be related to a decrease in myocardial contractility, which can no longer be compensated for by an increase in preload (as during submaximal exercise). Increases in systemic blood pressure may also compromise ventricular function but would seem to be of minor importance.

The haemodynamic response to exercise in chronic obstructive pulmonary disease: assessment by impedance cardiography.

This study aimed to determine the differences in haemodynamic responses to a standard incremental exercise test between outpatients with chronic obstructive pulmonary disease (COPD) and age-matched controls and to discover the relationship between severity of airflow obstruction and exercise haemodynamics in COPD. Twenty-two male patients with COPD (forced expiratory volume in one second (FEV1)/vital capacity (VC))<80% predicted) and 20 age-matched male controls performed an incremental exercise test (10 W x min(-1)) with ventilatory function and changes in stroke volume (deltaSV) and cardiac output (deltaCO) measured by means of electrical impedance cardiography (EIC). Submaximal deltaSV and deltaCO were lower in COPD patients. Peak exercise deltaSV were equal in patients and controls (128+/-33 versus 129+/-29%, p=0.98), whereas peak deltaCO was lower in patients (COPD versus controls: 232+/-71 versus 289+/-54%, p<0.005). In COPD patients, FEV1 (% pred) was significantly correlated to deltaSV at all submaximal exercise intensities, to peak exercise deltaSV and to peak exercise deltaCO. FEV1/VC (% pred) was significantly correlated to deltaSV at 30 and 60 W. In conclusion, in chronic obstructive pulmonary disease an aberrant haemodynamic response to exercise was found, especially in patients with severe airflow obstruction. This aberrant response is related to the degree of airflow obstruction and may limit exercise performance in patients with severe chronic obstructive pulmonary disease.

Adenosine deaminase: characterization and expression of a gene with a remarkable promoter.

Cosmid clones containing the gene for human adenosine deaminase (ADA) were isolated. The gene is 32 kb long and split into 12 exons. The exact sizes and boundaries of the exon blocks including the transcription start sites were determined. The sequence upstream from this cap site lacks the TATA and CAAT boxes characteristic for eukaryotic promoters. Nevertheless, we have shown in a functional assay that a stretch of 135 bp immediately preceding the cap site has promoter activity. This 135-bp DNA fragment is extremely rich in G/C residues (82%). It contains three inverted repeats that allow the formation of cruciform structures, a 10-bp and a 16-bp direct repeat and five G/C-rich motifs (GGGCGGG) disposed in a strikingly symmetrical fashion. Some of these structural features were also found in the promoter region of other genes and we discuss their possible function. Knowledge of the exact positions of the intron-exon boundaries allowed us to propose models for abnormal RNA processing that occurs in previously investigated ADA-deficient cell lines.

One adenosine deaminase allele in a patient with severe combined immunodeficiency contains a point mutation abolishing enzyme activity.

We have cloned and sequenced an adenosine deaminase (ADA) gene from a patient with severe combined immunodeficiency (SCID) caused by inherited ADA deficiency. Two point mutations were found, resulting in amino acid substitutions at positions 80 (Lys to Arg) and 304 (Leu to Arg) of the protein. Hybridization experiments with synthetic oligonucleotide probes showed that the determined mutations are present in both DNA and RNA from the ADA-SCID patient. In addition, wild-type sequences could be detected at the same positions, indicating a compound heterozygosity. Studies with ADA expression clones mutagenized in vitro showed that the mutation at position 304 is responsible for ADA inactivation.