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H H Mantsch

Publications and source records attributed to H H Mantsch.

At least 37 records · Page 2Linked to original sources
PubMed1999

Classification of breast tumors by grade and steroid receptor status using pattern recognition analysis of infrared spectra.

Infrared (IR) spectroscopy applied to tissue sections yields complex spectra that provide a molecular fingerprint of the tissue. We have studied a cohort of 77 breast tumors by IR spectroscopy to develop an objective method for the assignment of grade of breast tumors. Although the major variations between spectra from different tumors were in absorptions arising from triglycerides (adipose tissue) and collagen, subtle changes in spectra could be detected that were independent of cellularity and tissue composition. Using a specific multivariate pattern recognition strategy to associate these changes in spectra with different tumor grades, we then were able to accurately reclassify tumors by grade (87% accuracy; kappa = 0.835). A similar approach allowed classification of steroid receptor status (93% accuracy; kappa = 0.852). We conclude that IR spectroscopy may have clinical utility in the objective assignment of breast tumor grade.

Breast Neoplasms↗
PubMed1999

Infrared spectroscopy of exfoliated cervical cell specimens. Proceed with caution.

OBJECTIVE: To determine whether diagnostic information may be recovered from the infrared spectra of exfoliated cell specimens by using a novel spectral feature extraction method, in conjunction with linear and quadratic discriminant analysis, for spectral classification. STUDY DESIGN: Over 800 infrared spectra were included in the study, with corresponding clinical diagnoses based upon cytology and, when available, histology reports. Three sets of classification trials were carried out with the aim of distinguishing the spectra corresponding to normal specimens from CIN 1, 2 and 3. For each of these three cases, the procedure was to: (1) develop a set of provisional classification models using only a "training" subset of the spectra, and (2) test each provisional model by its ability to correctly predict the diagnoses on the basis of the remaining spectra. RESULTS: For optimal classification trials, training set classification accuracies were 68% for normal/CIN 1, 73% for normal/CIN 2 and 81% for normal/CIN 3; for the corresponding test sets the classification accuracies were 60%, 60% and 67%, respectively. CONCLUSION: The infrared spectra of exfoliated cervical cells carry information regarding the presence or absence of dysplasia, and that information is recoverable--albeit imperfectly at this stage--from the spectra of "real life" cell preparations.

Algorithms↗
PubMed1998

Infrared spectroscopic analysis of biomedical specimens using glass substrates.

We report on the use of glass substrates for the infrared spectroscopic analysis of dried serum, amniotic fluid, and synovial fluid films. New analytical applications of infrared spectroscopy are emerging rapidly, spurred largely by ever-improving instrumentation, combined with the widespread availability of powerful chemometric methods. We have recently begun to focus upon potential applications in both clinical chemistry and medical diagnostics. For example, serum analysis, the determination of fetal lung maturity, and the differential diagnosis of arthritis have all recently been demonstrated to be feasible on the basis of the infrared spectra of films dried from the appropriate samples (serum, amniotic fluid, or synovial fluid). However, the transition from the laboratory into clinical usage hinges on the availability of IR-transparent substrates that are both inexpensive and readily obtainable. We have demonstrated in this study that despite limited transparency in the IR region, clinical analyses and diagnostic spectral classifications may nevertheless be carried out using glass as a substrate for the IR measurements.

Amniotic Fluid↗
PubMed1998

Similarities between the sensitivity to 2-chlorodeoxyadenosine of lymphocytes from CLL patients and bryostatin 1-treated WSU-CLL cells: an infrared spectroscopic study.

Infrared (IR) spectroscopy was used to compare the drug resistance mechanism of cells from chronic lymphocytic leukemia (CLL) patients with that of WSU-CLL cells. Bryostatin 1 (Bryo 1), a macrocyclic lactone and protein kinase C activator, was used to render WSU-CLL cells more susceptible to 2-chlorodeoxyadenosine (2-CdA). The IR spectroscopic analysis revealed some changes in protein and DNA content in Bryo 1-treated WSU-CLL cells, however, the most significant alterations were observed in the membrane lipids, which resemble those found between 2-CdA-sensitive and 2-CdA-resistant cells from CLL patients. In addition, Bryo 1 treatment induced WSU-CLL cells to become CD11c, CD25 and tartrate-resistant acid phosphatase-positive, specific markers for hairy cell leukemia, a disease exquisitely sensitive to 2-CdA. Our results suggest that 2-CdA-sensitive CLL cells have cellular characteristics resembling the hairy cell stage. The similarity between the membrane lipids in 2-CdA-sensitive CLL cells and the Bryo 1-treated WSU-CLL cell line supports the suggestion that membrane lipid alteration might be an important step in the drug resistance mechanism of CLL cells.

Adult↗
PubMed1998

Prediction of RDS from amniotic fluid analysis: a comparison of the prognostic value of TLC and infra-red spectroscopy.

Infra-red (IR) spectroscopy was recently shown to be a sensitive method for the determination of fetal lung maturity (Liu et al., 1998). The present study was undertaken to validate the newly developed method for prediction of RDS (Respiratory Distress Syndrome). Samples of amniotic fluid were obtained by amniocentesis from 86 patients between the 28th and 41st week of pregnancy. A small volume, 35 microliters, of amniotic fluid was used to acquire infra-red spectra with a commercial spectrometer. The lecithin/sphingomyelin (L/S) ratio was determined separately by TLC (thin layer chromatography). A calibration model was established using a partial least squares regression analysis which quantitatively correlated 145 IR spectra with the TLC-based L/S ratios; the correlation coefficient was 0.95. The model was then validated using a total of 111 spectra which also showed a high correlation coefficient (r = 0.91). Based upon the clinical data associated with these samples, the prediction accuracy for the presence of RDS was 67 per cent for TLC and 83.3 per cent for IR. The accuracy for predicting the absence of RDS was 93.4 per cent for TLC and 96.8 per cent for IR. We conclude that IR spectroscopy has the potential to become the clinical method of choice for predicting RDS from amniotic fluid analysis.

Amniocentesis↗
PubMed1998

Two-dimensional mid-IR and near-IR correlation spectra of ribonuclease A: using overtones and combination modes to monitor changes in secondary structure.

We introduce near-IR spectroscopy as an ancillary tool for monitoring structural changes of proteins in aqueous solution using ribonuclease A (RNase A) as a model protein. The thermal unfolding of RNase A results in clear spectral changes in the near-IR and the mid-IR regions. In the near-IR the most pronounced changes are observed in the spectral region between 4820 and 4940 cm-1. The strong N-H combination band found at 4867 cm-1 in the spectrum of native RNase A shifts to 4878 cm-1 upon thermal unfolding. Hydrogen-deuterium exchange experiments that validate the N-H character of this mode can also be used to estimate the number of unexchanged amide protons after exposure to D2O. The transition profiles and temperatures derived from the temperature dependence of the N-H combination mode were found to be practically identical with those derived from the temperature dependence of the C = O amide I band in the mid-IR region, demonstrating that the near-IR region can be used as a conformation-sensitive monitor for the thermally induced unfolding of proteins in H2O solution. A 2-dimensional correlation analysis was applied to the mid-IR and near-IR spectra of RNase A to establish correlations between IR bands in both regions. The correlation analysis demonstrates that the thermal unfolding of RNase A is not a completely cooperative process; rather it begins with some changes in beta-sheet structure, followed by the loss of alpha-helical structures, and then ending with the unfolding of the remaining beta-sheets.

Amides↗
PubMed1998

Rapid determination of fetal lung maturity from infrared spectra of amniotic fluid.

OBJECTIVE: The purpose of this study was to determine the feasibility of infrared spectroscopy as an alternative method for the prediction of fetal lung development. STUDY DESIGN: Samples of amniotic fluid were obtained by amniocentesis from 134 patients between the 26th and 41st week of pregnancy. To acquire infrared spectra with a commercial spectrometer, 35 microl of amniotic fluid was required for each spectrum. The lecithin/sphingomyelin ratio was determined separately by thin-layer chromatography for each sample. A robust linear discriminant analysis method was used to partition the samples into normal and abnormal groups according to their infrared spectra. A partial least squares regression analysis was then applied to quantitatively correlate the infrared spectra with the thin-layer chromatography-based lecithin/sphingomyelin ratios. RESULTS: Qualitatively, the infrared spectra of the amniotic fluid in the validation set were successfully partitioned into lecithin/sphingomyelin <2 and lecithin/sphingomyelin >2 groups. Quantitatively, the lecithin/sphingomyelin ratios predicted from the infrared spectra of amniotic fluid were highly correlated and in excellent agreement with those determined by thin-layer chromatography (correlation coefficient = 0.893). CONCLUSION: Infrared spectroscopy has the potential to become the clinical method of choice for determining fetal lung surfactant maturity in amniotic fluid.

Amniocentesis↗
PubMed1998

Assessment of tissue viability using near-infrared spectroscopy.

Prolonged and severe tissue hypoxia results in tissue necrosis in pedicled flaps. We demonstrate the potential of near-infrared spectroscopy for monitoring of skin flaps. This approach clearly identifies tissue regions with low oxygen supply, and also the severity of this challenge, in a rapid and non-invasive manner with a high degree of reproducibility. Tissue haemoglobin oxygen saturation and water content of pre-selected dorsal sites were monitored for 72 h prior to, and 72 h following elevation of a reversed McFarlane rat dorsal skin flap (n = 9). Oxygen delivery to flap tissue dropped immediately upon flap elevation. This was most pronounced in the distal half of the flap and least pronounced in the region nearest its base. Haemoglobin oxygen saturation of tissue proximal to the vascular base of the flap recovered, exceeding pre-elevation saturation values, within 6 h of raising the flap. Typically, this higher haemoglobin oxygen saturation persisted for the full 72 h post-elevation observation period. At a distance greater than 2 cm from the vascular pedicle, the tissue remained hypoxic over the post-elevation monitoring period. Tissues remaining below a certain haemoglobin oxygen saturation threshold (oxygen saturation index < 1) for prolonged periods (> 6 h) became increasingly dehydrated, eventually becoming visibly necrotic. Tissues above this threshold (oxygen saturation index > 1), despite being significantly hypoxic, relative to the pre-elevation saturation values, remained viable over the 72 h post-elevation monitoring period.

Animals↗
PubMed1998

Tissue viability by multispectral near infrared imaging: a fuzzy C-means clustering analysis.

Clinically, skin color, temperature, and capillary perfusion are used to assess tissue viability following microvascular tissue transfer. However, clinical signs that arise as a consequence of poor perfusion become evident only after several hours of compromised perfusion. This study demonstrates the potential usefulness of optical/infrared multispectral imaging in the prognosis of tissue viability immediately post-surgery. Multispectral images of a skin flap model acquired within 1 h of surgical elevation are analyzed in comparison to the final 72-h clinical outcome with a high degree of correlation. Regional changes in tissue perfusion and oxygenation present immediately following surgery are differentiated using fuzzy clustering and image processing algorithms. These methodologies reduce the intersubject variability inherent in infrared imaging methods such that the changes in perfusion are reproducible and clearly distinguishable across all subjects. Clinically, an early prognostic indicator of viability such as this would allow for a more timely intervention following surgery in the event of compromised microvasculature.

Algorithms↗
PubMed1998

Multianalyte serum analysis using mid-infrared spectroscopy.

This study assesses the potential for using mid-infrared (mid-IR) spectroscopy of dried serum films as the basis for the simultaneous quantitation of eight serum analytes: total protein, albumin, triglycerides, cholesterol, glucose, urea, creatinine and uric acid. Infrared transmission spectra were acquired for 300 serum samples, each analysed independently using accepted reference clinical chemical methods. Quantitation methods were based upon the infrared spectra and reference analyses for 200 specimens, and the models validated using the remaining 100 samples. Standard errors in the IR-predicted analyte levels (Sy/x) were 2.8 g/L (total protein), 2.2 g/L (albumin), 0.23 mmol/L (triglycerides), 0.28 mmol/L (cholesterol), 0.41 mmol/L (glucose) and 1.1 mmol/L for urea, with correlation coefficients (IR vs reference analyses) of 0.95 or better. The IR method emerged to be less suited for creatinine (Sy/x = mumol/L) and uric acid (Sy/x = 140 mumol/L) due to the relatively low concentrations typical of these analytes.

Blood Chemical Analysis↗
PubMed1998

Sequential treatment of human chronic lymphocytic leukemia with bryostatin 1 followed by 2-chlorodeoxyadenosine: preclinical studies.

We have previously reported that bryostation 1 (Bryo 1) induces differentiation of chronic lymphocytic leukemia (CLL) in vitro to a hairy cell (HC) stage. This study tests the hypothesis that Bryo 1-differentiated CLL cells are more susceptible to 2-chlorodeoxyadenosine (2-CdA) than parent CLL cells. A recently established EBV-negative CLL line (WSU-CLL) from a patient resistant to chemotherapy including fludarabine was used to test this hypothesis. Both Bryo 1 (10-1000 nM) and 2-CdA (5.6-22.4 microM) exhibited a dose-dependent growth inhibitory effect on the WSU-CLL cell line. In vitro, the sequential exposure to Bryo 1 (100 nM for 72 h) followed by 2-CdA (11.2 microM) resulted in significantly higher rates of growth inhibition than either agent alone. Changes in immunophenotype, enzymes, lipids, proteins, and the DNA of WSU-CLL cells were studied before and after Bryo 1 treatment. Bryo 1 induced a positive tartrate-resistant acid phosphatase reaction and two important markers, CD11c and CD25, after 72 h of culture, confirming the differentiation of CLL to HC. The Fourier transformation infrared spectroscopic analysis showed that the amount of membrane lipids significantly increased in Bryo 1-treated cells compared to controls after 24 h, whereas the protein content, as well as the DNA content, decreased. This finding supports the change of CLL to HC. To evaluate the in vivo efficacy of Bryo 1 and 2-CdA, we used a xenograft model of CLL in WSU-CLL-bearing mice with severe combined immune deficiency. s.c. tumors were developed by injection of 10(7) WSU-CLL cells, and fragments were then transplanted into a new batch of severe combined immunodeficient mice. Bryo 1 and 2-CdA at the maximum tolerated doses (75 micrograms/kg i.p. and 30 mg/kg s.c., respectively) were administered to the mice at different combinations and schedules. The survival in days, the tumor growth inhibition ratio, the tumor growth delay, and the log10 kill of the mice treated with Bryo 1 followed by 2-CdA were significantly better than the control and other groups. We conclude that the sequential treatment with Bryo 1 followed by 2-CdA resulted in higher antitumor activity and improved animal survival.

Acid Phosphatase↗
PubMed1998

Infrared microscopic functional group mapping and spectral clustering analysis of hypercholesterolemic rabbit liver.

Fourier transform infrared microscopy has been applied to the characterization of hypercholesterolemic rabbit liver. A combination of the traditional "group frequency" approach to spectral interpretation and the technique of functional group mapping was applied to aid understanding of the spectral changes observed between normal and hypercholesterolemic liver. Using this approach, spectral differences could be attributed to the accumulation of cholesterol esters (most likely in the form of lipoprotein complexes) in the hypercholesterolemic liver. A novel approach, spectral clustering, was used to identify regions of hypercholesterolemic liver tissue which possessed similar spectral (and by inference similar biochemical/histological) properties. Using this approach, a complex data set consisting of 400 discrete spectra acquired from an area of tissue approximately 1 x 1 mm could be reduced to five types of spectra, and the distribution of each type of spectrum within the tissue analyzed.

Algorithms↗
PubMed1998

Biochemical imaging and 2D classification of keratin pearl structures in oral squamous cell carcinoma.

Precise regulation of cell organization results in well-differentiated tissue structures and continuous renewal of the oral epithelium maintaining a highly ordered tissue architecture. Here we demonstrate that FT-IR microspectroscopy, performed on sections of cancerous tissue biopsies, is capable of generating biochemical maps that show the distribution and any abnormal concentration of individual classes of biomolecules. Oral epithelia affected by cancer (squamous cell carcinoma) show many abnormal changes in morphology, of which the formation of keratin pearls is only one. Spectra from selected pearl areas demonstrate that these structures contain not only abnormal keratin concentrations but also seem to be stabilized by surrounding collagen fibers. Infrared image maps reveal that in the center of keratin pearls the concentration of protein (cytokeratins) is abnormally high, that DNA is absent and that the cell membrane fluidity is reduced. This suggests that cells are structurally destroyed and transformed into nuclei-free horny cells, simulating normal differentiation and epithelial growth. We also introduce a new analysis modality, two-dimensional (2D) tissue classification, and apply it to establish spectral similarities between different tissue structures. A total of 315 spectra, recorded for the original map, were analyzed by pattern recognition methods, classified and re-assembled into new maps based on their spectral similarities. The re-assembled maps clearly indicate significant tissue changes outside the pearls, suggesting early biochemical changes that accompany abnormal growth. Employing this 2D analysis modality in combination with infrared histopathology may be relevant to tumor diagnosis and prognosis.

Cluster Analysis↗
PubMed1998

In situ infrared histopathology of keratinization in human oral/oropharyngeal squamous cell carcinoma.

Fourier transform infrared (FTIR) microspectroscopy is emerging as a promising new tool for histopathological investigations of tissue histochemistry. This study was designed to assess whether changes in tissue biochemistry induced by well-differentiated and poorly differentiated oral/oropharyngeal squamous cell carcinoma (SCC) can be detected by infrared spectroscopy. The biopsies analyzed were each proven SCC positive and compared with tissue taken from the contralateral normal site. Individual infrared spectra, recorded from specific tissue areas, were correlated with histopathological structures normally found in the oral mucosa. Infrared mapping of these areas allows the generation of biochemical images of molecular structures such as lipids, sugars, and proteins. The visualization of DNA and tissue structures containing keratin (well expressed in all epithelia) reveals distinct differences between normal and SCC-positive biopsies. Bivariate histogram analysis of cell components (e.g., DNA and keratin) indicated that cancer cells produce a relatively homogeneous and clearly abnormal cell biochemistry, whereas differentiated epithelial cells present a very heterogeneous distribution of cellular components. Using these features, tissue containing abnormal or cancer cells can easily be distinguished from normal epithelial structures. The abnormal keratin distribution in poorly differentiated SCC and in keratin pearls (present only in well-differentiated SCC) offers insight into the process of malignant tissue transformation in squamous epithelium. Applying infrared microspectroscopy in combination with bivariate statistics to histopathological tissue thin sections provides a potential diagnostic tool for detection of cell changes in epithelial cancers.

Aged↗
PubMed1997

Infrared spectroscopy of human apolipoprotein fragments in SDS/D2O: relative lipid-binding affinities and a novel amide I assignment.

Infrared absorption spectra are reported for six apolipoprotein fragments in SDS/D2O. Five of the peptides correspond to proposed lipid-binding domains of human apolipoproteins [apoC-I(7-24), apoC-I(35-53), apoA-II(18-30)+, apoA-I(166-185), apoE(267-289)], and the sixth is the de novo lipid associating peptide LAP-20. The amide I infrared absorption patterns are generally consistent with predominantly helical structures (as determined previously by NMR spectroscopy and distance geometry calculations) and further suggest that apoA-I(166-185) and apoE(267-289) are bound to SDS relatively weakly in comparison to the other four peptides. The latter conclusion is also supported by the temperature dependence of the infrared spectra, as increasing temperature promotes a distinct increase in random coil structure only for apoA-I(166-185) and apoE(267-289). In addition to features readily ascribed to helices, the infrared spectra of all the peptides show absorptions in the spectral region 1630-1635 cm-1 that is usually associated with beta-structure, a motif that is clearly absent from the NMR-derived structures. Parallel difficulties also arose in the analyses of the circular dichroism spectra. We suggest that both the low-frequency infrared absorptions and the ambiguities in interpreting the CD spectra may be due to unusual structures at the peptide C-termini, involving C=O groups that form hydrogen bonds simultaneously either with two solvent molecules or with donors from the backbone (NH) and the solvent (OH). Analogous absorptions may be a general feature of solvent-exposed helices, which suggests a need for caution in assigning amide I bands below 1640 cm-1.

Amino Acid Sequence↗
PubMed1997

Methylmercury-induced alterations in lung and pulmonary surfactant properties of adult mice.

Exposure to methylmercuric chloride (MMC) has been shown to significantly affect development of the lung and pulmonary surfactant system of the fetus. Preliminary results suggest it may also affect adult lung and associated bronchoalveolar lavage (BAL), which represents the extracellular surfactant pool. To determine if mercury exposure has the potential to alter surfactant function, adult mice were treated with MMC, 15 mg/kg by intragastric intubation on 4 successive days. BAL was collected by repeated intratracheal lavage 24 h after the last treatment. Nucleated cell numbers in lavage were determined. Tissue was prepared for scanning electron microscopy (SEM). Lavage fluid was extracted into chloroform:methanol and phospholipid concentration determined. A sample of the extract was used at a constant phospholipid concentration to measure surface activity on a bubble surfactometer. Lung weight to body weight ratio increased whereas total numbers of nucleated cells in BAL were not altered by MMC. SEM of samples from lungs of animals exposed to MMC showed normal architecture. Surface tension measurements suggest that the mean time to minimum surface tension and the minimum surface tension were greater in BAL from mice exposed to MMC for 4 days. In addition samples of BAL were prepared for Fourier-transform infrared spectrophotometry (FT-IR). Spectra showed changes in both lipid and protein components of BAL. Morphometric analyses of micrographs showed that mean alveolar diameter was reduced and wall thickness increased after mercury exposure. These results suggest that methylmercury exposure may significantly affect surface tension characteristics and composition of BAL, possibly through leakage of edematous interstitial tissue.

Animals↗
PubMed1997

Structural and catalytic properties of CMP kinase from Bacillus subtilis: a comparative analysis with the homologous enzyme from Escherichia coli.

CMP kinases from Bacillus subtilis and from Escherichia coli are encoded by the cmk gene (formerly known as jofC in B. subtilis and as mssA in E. coli). Similar in their primary structure (43% identity and 67% similarity in amino acid sequence), the two proteins exhibit significant differences in nucleotide binding and catalysis. ATP, dATP, and GTP are equally effective as phosphate donors with E. coli CMP kinase whereas GTP is a poor substrate with B. subtilis CMP kinase. While CMP and dCMP are the best phosphate acceptors of both CMP kinases, the specific activity with these substrates and ATP as donor are 7- to 10-fold higher in the E. coli enzyme; the relative Vm values with UMP and CMP are 0.1 for the B. subtilis CMP kinase and 0.01 for the E. coli enzyme. CMP increased the affinity of E. coli CMP kinase for ATP or for the fluorescent analog 3'-anthraniloyl dATP by one order of magnitude but had no effect on the B. subtilis enzyme. The differences in the catalytic properties of B. subtilis and E. coli CMP kinases might be reflected in the structure of the two proteins as inferred from infrared spectroscopy. Whereas the spectrum of B. subtilis CMP kinase is dominated by a band at 1633 cm-1 (representing beta type structures), the spectrum of the E. coli enzyme is dominated by two bands at 1653 and 1642 cm-1 associated with alpha-helical and unordered structures, respectively. CMP induced similar spectral changes in both proteins with a rearrangement of some of the beta-structures. ATP increases the denaturation temperature of B. subtilis CMP kinase by 9.3 degrees C, whereas in the case of the E. coli enzyme, binding of ATP has only a minor effect.

Amino Acid Sequence↗