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Biomedical subjects

Ling Qin

Publications and source records attributed to Ling Qin.

At least 55 records · Page 3Linked to original sources

Low BMD is a risk factor for low-energy Colles' fractures in women before and after menopause.

UNLABELLED: Until now, it was unclear if low volumetric bone mineral density at the distal radius was also a risk factor for Colles' fracture, especially in patients with low-energy trauma. In our study, we used peripheral quantitative computed tomography to measure volumetric bone mineral density of a nonfractured distal radius and dual-energy x ray absorptiometry to measure areal bone mineral density at the spine and hip in patients with Colles' fractures, including 45 women who were premenopausal (age range, 40-50 years) and 39 women who were postmenopausal (age range, 51-65 years). In each group, the patients were subdivided into low-energy and high-energy fracture groups. Ninety-five age-matched healthy women who were premenopausal and 90 age-matched healthy women who were postmenopausal without fracture history served as controls. The results showed that patients with low-energy fractures had a lower bone mineral density at all measurement sites, compared with either patients with high-energy fractures or control subjects. More patients were found with a bone mineral density less than -2.5 standard deviations (Z-score) in the premenopausal group (12.5% measured by dual-energy x ray absorptiometry and 41.2% measured by peripheral quantitative computed tomography) than in the postmenopausal group (6.0% measured by dual-energy x ray absorptiometry and 4.8% measured by peripheral quantitative computed tomography). These results suggest that low bone mineral density, particularly measured using peripheral quantitative computed tomography at the distal radius of women who were premenopausal, was an important risk factor for low-energy Colles' fractures. LEVEL OF EVIDENCE: Prognostic study, Level I-1 (prospective study). See the Guidelines for Authors for a complete description of levels of evidence.

Absorptiometry, Photon↗

[Relation of pbp2B, ermB, ermA/B, mefA genes with resistance to penicillin and erythromycin among Streptococcus pneumoniae isolates from children].

OBJECTIVE: To investigate the relation of pbp2B, ermB, ermA/B and mefA genes to penicillin and erythromycin resistance among isolated Streptococcus pneumoniae (Sp) in children. METHODS: Twenty-six strains of Sp were collected from September 2002 to April 2003 at the Children Hospital of Suzhou University. (1) Twenty-six pneumococcal isolates were obtained from respiratory tract secretions of children with respiratory diseases. (2) Susceptibility of the isolates to penicillin, cefuroxime, ceftriaxone, cefotaxime and erythromycin was determined by E-test. (3) The genes pbp2B, ermB, ermA/B and mefA of the isolates were detected with PCR. (4) The PCR product of pbp2B gene was sequenced. (5) DNA sequences of pbp2B of pneumococcal isolates were compared with those of SpR6 [penicillin sensitive (www.ncbi.nlm.gov/nucleotide, NC-003098)]. RESULTS: Among the 26 isolates studied, pbp2B gene mutation was found in 15(58%) isolates, all were point mutation of A, B, C and D genotypes which were seen in 11(73%), 2(13%), 1(7%) and 1(7%), respectively. The numbers of isolates susceptible to penicillin, cefuroxime, ceftriaxone and cefotaxime were 9(82%), 10(91%), 11(100%) and 11(100%), of 11 non-mutation isolates;numbers of isolates resistant to penicillin, cefuroxime, ceftriaxone, and cefotaxime were 13(87%), 11(73%), 1(7%) and 1(7%) out of 15 isolates with mutation.ErmB, ermA/B, mefA and erm/mef genes were positive in 9(35%), 16(62%), 7(27%) and 21(81%)isolates. MIC of erythromycin was 2 to > 256 mg/L among pneumococcal isolates with erm/mef genes. CONCLUSION: Among antibiotic resistant pneumococcal isolates in the area, the main basis of penicillin resistance was the mutation of pbp2B genes. Genotype A mutation had the highest rate among the isolates with mutation and manifested as resistance to penicillin and cefuroxime. Expression of either all or any of the ermA, ermB and mef genes led to erythromycin resistance. Antibiotics resistant Sp strains in this area are forming a challenge to efficacy of penicillin and erythromycin.

Aminoacyltransferases↗

[Study on the molecule epidemiological between resistances of 7 genes interrelated 4 antibiotic to isolated Streptococcus pneumoniae in children].

OBJECTIVE: To investigate the molecule epidemic for 7 genes interrelated penicillin, erythromycin, tetracycline, vancomycin resistance of isolated Streptococcus pneumoniae (SP) in children at Suzhou area. METHODS: (1) Thirty-one pneumococcal isolates were collected from respiratory tract secretions of children with respiratory diseases from Nov 2002 to Apr 2003 at the Children's Hospital of Suzhou University (reference strain ATCC49619). (2) Penicillin susceptibility was determined by E-test, while erythromycin, tetracycline, vancomycin were determined by K-B disk. (3) The detecting of pbp2B, ermA/B, mefA, tetM, vanA, vanB genes by PCR, Sequencing pbp2B genes, Contrasting pbp2B DNA sequences among pneumococcal isolates and SP R6 [penicillin sensitive (www.ncbi.nlm.gov/nucleotide, NC-003098)]. RESULTS: Of thirty-one isolates studied, the results were shown as follows; (1) Penicillin sensibility 38.7% (n = 12), penicillin resistance 61.3% (n = 19), pbp2B mutation 64.5% (n = 20); (2) Erythromycin sensibility 9.7% (n = 3), erythromycin resistance 90.3% (n = 28), ermA/B 71% (n = 22), mefA 32.1% (n = 10), ermA/B + mefA 87.1% (n = 27); (3) Tetracycline sensibility 9.7% (n = 3), tetracycline resistance 90.3% (n = 28), tetM 90.3% (n = 28); (4) Vancomycin sensibility 100% (n = 31), vanA, vanB all 0%. CONCLUSION: Among pneumococcal isolates at our area, penicillin, erythromycin, tetracycline resistance were high, vancomycin was sensitive. Detecting 7 genes interrelated penicillin, erythromycin, tetracycline, vancomycin resistance expressed genotypies for antibiotic resistances in pneumococcal isolates.

Anti-Bacterial Agents↗

[Successful treatment of agammaglobulinemia by HLA-mismatched unrelated cord blood stem cell transplantation--the first case report].

OBJECTIVE: To evaluate cord blood stem cell transplantation (CBT) in the treatment of X-linked agammaglobulinemia, and observe the courses of the hematopoietic and immune reconstitution. METHODS: A 14-year-old male patient with agammaglobulinemia received CBT from a 1/6 HLA-mismatched unrelated cord blood. The conditioning regimen was Bu/Cy/anti-CD3 antibody. CsA was given together with MMF and MTX for prophylaxis of GVHD. The patient received 0.42 x 10(8) nucleated cells/kg, containing 0.35 x 10(6) CD34(+) cells/kg. RESULTS: The recipient showed hematopoietic reconstitution on day 30 post-transplantation when ANC was 0.5 x 10(9)/L and BPC 20 x 10(9)/L. Sex chromosome analysis showed engraftment (donor 46, XX/recipient 46, XY = 4:1) on day 45. The recipient's blood group changed from AB to O, IgG from 1.1 g/L to 3.5 g/L, sex chromosome from 46, XY to full 46, XX, and mature B cells in peripheral blood from 0 to 5% on day 100, indicating immune reconstitution. At the last follow-up of 360 days, the patient without acute or chronic GVHD showed normal hemogram and myelogram, IgG 13.5 g/L and 10% mature B cells in peripheral blood, indicating the hematopoiesis and immune persistent reconstitution. No acute or chronic GVHD was developed. CONCLUSION: This is the first case report of successful treatment of X-linked agammaglobulinemia by HLA-mismatched unrelated CBT.

Adolescent↗

Interaction of excitatory and inhibitory frequency-receptive fields in determining fundamental frequency sensitivity of primary auditory cortex neurons in awake cats.

Harmonic complex tones produce pitch-height perception corresponding to the fundamental frequency (F0). This study investigates how the spectral cue of F0 is processed in neurons of the primary auditory cortex (A1) with sustained-response properties. We found F0-sensitive and -insensitive cells: the former discriminated between harmonics and noise, while the latter did not. F0-sensitive cells preferred F0s corresponding to the best frequency (BF) and 0.5 x BF. The F0-sensitivity to F0=0.5 x BF was preserved for missing F0, but abolished by eliminating both F0 and the second harmonic. The inhibitory subfield of the frequency-receptive field was restricted to the spectral region between the preferred harmonics in F0-sensitive cells, while it was frequency unspecific in F0-insensitive cells. We conclude that (i) A1 is well organized for discrimination between harmonics and noise; (ii) pitch-height is represented along with the tonotopic axis; (iii) all aspects of the sustained neural responses to harmonic and noise stimuli are consequences of spectral filtering; and (iv) although the observed cell behavior explains some psychophysical pitch perception behaviors, such as pitch-chroma (helical pitch perception with frequency elevation), pitch-level tolerance and adaptive behavior, F0-encoding in A1 remains at the incomplete perceptual level (dominance of the third to fifth harmonics for pitch strength is unexplainable by the cell behavior).

Acoustic Stimulation↗

Parathyroid hormone uses multiple mechanisms to arrest the cell cycle progression of osteoblastic cells from G1 to S phase.

Parathyroid hormone (PTH) plays a major role in bone remodeling and has the ability to increase bone mass if administered daily. In vitro, PTH inhibits the growth of osteoblastic cell lines, arresting them in G(1) phase. Here, we demonstrate that PTH regulates the expression of at least three genes to achieve the following: inducing expression of MAPK phosphatase 1 (MKP-1) and p21(Cip1) and decreasing expression of cyclin D1 at both mRNA and protein levels. The induction of MKP-1 causes the dephosphorylation of extracellular signal-regulated kinase and therefore the decrease in cyclin D1. Overexpression of MKP-1 arrests UMR cells in G(1) phase. The mechanisms involved in PTH regulation of these genes were studied. Most importantly, PTH administration produces similar effects on expression of these genes in rat femoral metaphyseal primary spongiosa. Analyses of p21(Cip1) expression levels in bone indicate that repeated daily PTH injections make the osteoblast more sensitive to successive PTH treatments, and this might be an important feature for the anabolic functions of PTH. In summary, our data suggest that one mechanism for PTH to exert its anabolic effect is to arrest the cell cycle progression of the osteoblast and hence increase its differentiation.

Animals↗

Amphiregulin is a novel growth factor involved in normal bone development and in the cellular response to parathyroid hormone stimulation.

Parathyroid hormone (PTH) is the major mediator of calcium homeostasis and bone remodeling and is now known to be an effective drug for osteoporosis treatment. Yet the mechanisms responsible for its functions in bone are largely unknown. Here we report that the expression of amphiregulin (AR), a member of the epidermal growth factor (EGF) family, is rapidly and highly up-regulated by PTH in several osteoblastic cell lines and bone tissues. Other osteotropic hormones (1alpha,25-dihydroxyvitamin D3 and prostaglandin E2) also strongly stimulate AR expression. We found all EGF-like ligands and their receptors are expressed in osteoblasts, but AR is the only member that is highly regulated by PTH. Functional studies demonstrated that although AR is a potent growth factor for preosteoblasts, it completely inhibits further differentiation. AR also strongly and quickly stimulated Akt and ERK phosphorylation and c-fos and c-jun expression in an EGF receptor-dependent manner. Moreover, AR null mice displayed significantly less tibial trabecular bone than wild-type mice. Taken together, we have identified a novel growth factor that is PTH-regulated and appears to have an important role in bone metabolism.

Amphiregulin↗

Spectral-shape preference of primary auditory cortex neurons in awake cats.

The study of the influence of spectral envelopes of complex tones on cortical neuron discharges is important with respect to understanding the formant processing of vowels. That the sharpness of formants can contribute to the vowel quality has previously been shown in psychophysical experiments. However, it is unknown how this parameter is reflected by cortical neuron discharges, especially when a formant falls into different portions of the neuronal frequency receptive field (FRF). To show this is the aim of this study focusing on the sustained discharging neurons in the low frequency portion of cat primary auditory cortex (A1). The stimuli were multi-frequency tones whose spectral envelope was sinusoidally modulated with a peak fixed at a neuron's best frequency. The modulation depth, defined as damping-amplitude (DA), varied systematically. Stimulus bandwidth also varied systematically. Large DA at off-center frequencies produces a prominent spectral peak with steep slope, whereas small DA has a less well-defined spectral peak with gentle slope. Single frequency and two tone stimuli served to delineate the excitatory and inhibitory subfields of FRF. The A1 neuron preferred large DA when the sound energy fell into FRF with the relatively large inhibitory-subfield, while the same cell preferred small DA when it fell into FRF with the relatively small inhibitory-subfield. It is concluded that the A1 neuron can estimate steepness of slope of a spectral peak, and that a preference for steep slopes stems from a shift of balance toward the spectral inhibition, whereas a preference for gentle slopes, toward the spectral excitation.

Acoustic Stimulation↗

Suppression of auditory cortical activities in awake cats by pure tone stimuli.

Based on the time courses of excitatory spike-responses to pure-tone stimuli, neurons in the primary auditory cortex (A1) of awake cats have been classified into the phasic cell (P-cell), the tonic cell (T-cell), and the phasic-tonic cell (PT-cell). In the present study, taking advantage of the presence of the spontaneous spike-activities of A1 neurons in awake animals, time courses of suppressive spike-responses to pure-tone stimuli were studied by constructing spectro-temporal spike-activity diagrams. In P-cell, the suppression and excitation temporally alternated and spectrally co-occurred, restricting excitatory spike-responses within narrow temporal limits but not setting the spectral limits. In T-cell, the suppression and excitation spectrally alternated and temporally co-occurred, restricting excitatory frequency-tuning but not setting the time limits. PT-cell has mixed response properties of P- and T-cells. The findings suggest that: (1) P-cell analyzes temporal information of the sound without active spectral limits, (2) T-cell analyzes spectral information without limits of time, and (3) PT-cell analyzes spectrally and temporally complex auditory information. Taken in the light of recent findings that the shift of the balance of the synaptic excitation and inhibition results in the spike-activity modulation of the cerebral cortical neurons, it is suggested that the temporal shift of the balance of the excitation and inhibition works in P-cell; the spectral shift, in T-cell; and the combination of the temporal and spectral shifts, in PT-cell, underlying the functional differences between cell-types.

Acoustic Stimulation↗

Spectral-edge sensitivity of primary auditory cortex neurons in alert cats.

Although psychophysical studies have revealed involvement of spectral edges in auditory perception, little is known about neural processing. This study investigates how spectral edges are processed in neurons of alert cat primary-auditory-cortex (A1) with sustained response property. Stimuli are low-pass, high-pass and band-pass tones with sharp spectral edges whose edge-frequencies were systematically shifted, constructing edge-frequency response functions. Pure- and two-tone stimuli served to delineate excitatory and inhibitory subfields of the frequency response field (FRF). Based on the response function characteristics, cells were divided into edge-sensitive and edge-insensitive cells: the edge sensitive cells had narrow tuning to the high-edge (type-II cells) or low-edge (type-III cells) frequencies, while the edge insensitive cells were driven by any static stimuli with energy on FRF (type-I) or only very narrowband stimuli with energy confined to FRF (type-IV cells). Edge-sensitive cells showed a close correlation between the best frequencies of the single-frequency (BFSF) and edge-frequency (BFEF) response functions and between their half-height bandwidths, suggesting that the edge-frequency identification is processed along the tonotopic axis in A1. BFSF shifted (mean 0.11 octaves) into the stimulus band from the BFEF (closely corresponding to pitch shift into stimulus band from the edge frequency in human psychophysical data of edge-pitch), suggesting central mechanism of edge-pitch sensation. Type-I cells had non-significant inhibitory subfields of FRF; type-II cells had the significant inhibitory subfield on the higher frequency side; type-III cells, on the lower frequency side; and type-IV cells, on both sides, suggesting that the inhibitory mechanism characterizes the cell-type specific spectral-edge sensitivity.

Animals↗

Plant degradation: a nematode expansin acting on plants.

Expansin proteins, which have so far been identified only in plants, rapidly induce extension of plant cell walls by weakening the non-covalent interactions that help to maintain their integrity. Here we show that an animal, the plant-parasitic roundworm Globodera rostochiensis, can also produce a functional expansin, which it uses to loosen cell walls when invading its host plant. As this nematode is known to be able to disrupt covalent bonds in plant cell walls, its accompanying ability to loosen non-covalent bonds challenges the prevailing view that animals are genetically poorly equipped to degrade plant cell walls.

Animals↗

Correlation study of scanning acoustic microscope reflection coefficients and image brightness intensities of micrographed osteons.

Scanning acoustic microscopy (SAM) of Haversian bone at high frequency clearly shows differences in the brightness (gray) levels of individual osteons, which were observed to correspond to the differences in reflection coefficients measured with the SAM technique: the darker the bony regions on the SAM micrographs, the lower the SAM reflection coefficient values, and vice versa. We studied the correlation between differences in brightness and the related reflection coefficients of osteons on undecalcified transverse sections of goat tibial diaphysis using a 400-MHz burst mode lens on the Olympus UH3 SAM. Results showed that there was a strong linear correlation between brightness intensities and the corresponding reflection coefficients, with a correlation coefficient r = 0.99 ( P << 0.001) using gray level 210 as cutoff. This result suggested that the image brightness intensity of osteonic bone could be measured retrospectively to provide information on the stiffness of the corresponding bone matrix.

Acoustics↗

Bone densitometry: which skeletal sites are best predicted by bone mass determinants?

Evaluation of bone mineral content/bone mass density (BMC/BMD) is important to determine bone mass development among adolescents in health and disease. It is uncertain at which skeletal site BMC/BMD is best predicted by bone mass determinants. On the other hand, intrapersonal BMC/BMD data can be clustered into a composite index score to facilitate correlation and outcome prediction analysis. This study aimed to identify the skeletal site that was best predicted by bone mass determinants and to develop a composite index score based on multisite BMC/BMD values in healthy adolescent girls. Eleven BMD/BMC variables per subject were evaluated by using dual-energy X-ray absorptiometry (DXA) and peripheral quantitative computed tomography (pQCT) in 236 healthy girls aged 12-15 years. Bone mass determinants, namely, weight, height, puberty, dietary calcium, physical activity, and bone turnover markers, were determined. Factor analysis was used to develop composite index scores that summarized characteristics of multisite BMC/BMD. Results showed that lumbar spinal BMD and BMC (by DXA) and tibial integral BMD (by pQCT) were the BMC/BMD sites better predicted by bone mass determinants (R2, 0.57-0.77) in multiple regression analysis. On the other hand, three composite index scores representing areal BMD, areal BMC, and vBMD were derived to summarize the original BMC/BMD values. The composite index scores had similar predicting power (R2, 0.419-0.749) compared to those of original BMC/BMD, indicating that the composite index scores were representative of the original variables. To conclude, lumbar spinal BMD and BMC and tibial integral BMD were the three BMC/BMD variables better predicted by bone mass determinants. This evaluation would help select appropriate skeletal sites as outcome measures for bone mass evaluation in future studies. Also, the development of composite index scores could help reduce the number of variables for correlation and outcome prediction analyses.

Absorptiometry, Photon↗

Correlations of calcaneal QUS with pQCT measurements at distal tibia and non-weight-bearing distal radius.

Quantitative ultrasound (QUS) is used for prediction for risks of osteoporotic fractures at various skeletal sites, irrespective of weight-bearing or non-weight-bearing skeletons. In the current study, we investigated the correlation between calcaneal QUS measurements (BUA, VOS, and Soundness) and volumetric trabecular, cortical, and its integral bone mineral density (tBMD, cBMD, and iBMD) using peripheral quantitative computed tomography (pQCT) of the weight-bearing distal tibia and non-weight-bearing distal radius in 198 healthy Chinese women between 40 and 62 years of age. Results showed that BUA, VOS, and Soundness measured by calcaneal QUS were significantly correlated with tBMD, cBMD, and iBMD of both distal tibia and distal radius (r = 0.210-0.447; all P < 0.01). The correlation coefficients of all the individual parameters between calcaneus and distal tibia were correspondingly higher (r = 0.214-0.447; all P < 0.01) than that of distal radius (r = 0.210-0.368; all P < 0.01). QUS Soundness showed the highest correlation (r = 0.447; P < 0.01) with tBMD of distal tibia when comparing with all other parameters between these two measurement devices. Stronger "within-device" correlations (r = 0.640-0.764; all P < 0.01) were found in pQCT measurements between distal tibia and radius. In addition, the largest and significant age-related decline was found in tBMD of the distal radius measured by pQCT and Soundness of the QUS measurement in the postmenopausal group. In conclusion, heel QUS measurement demonstrated slightly better correlation with trabecular bone of the weight-bearing skeleton than that of the non-weight-bearing skeleton measured by pQCT.

Adult↗

A randomized, prospective study of the effects of Tai Chi Chun exercise on bone mineral density in postmenopausal women.

OBJECTIVE: To evaluate the potential benefits of programmed Tai Chi Chun (TCC) exercise on the weight-bearing bones of early postmenopausal women. DESIGN: Age-matched and randomized prospective intervention. SETTING: University medical school. PARTICIPANTS: One hundred thirty-two healthy postmenopausal women (mean age, 54.0+/-3.5y) within 10 years of menopause onset were recruited and randomized into the TCC exercise group (n=67) or the sedentary control group (n=65). INTERVENTION: Supervised TCC exercise was performed by the TCC group for 45 minutes a day, 5 days a week, for 12 months; control subjects retained a sedentary life style. Main outcome measures Bone mineral density (BMD) was measured in the lumbar spine and proximal femur by using dual-energy x-ray absorptiometry and in the distal tibia by using multislice peripheral quantitative computed tomography (pQCT). All BMD measurements were repeated after 12 months in both groups. Fracture rate was also documented. RESULTS: Baseline measurements showed homogeneity in age, anthropometric variables, and menstruation status between the TCC and control groups. Exactly 81.6% of the subjects in the TCC group and 83.1% of subjects in the control group completed the 12-month follow-up study. BMD measurements revealed a general bone loss in both TCC and sedentary control subjects at all measured skeletal sites, but with a reportedly slower rate in the TCC group. A significant 2.6- to 3.6-fold retardation of bone loss (P<.01) was found in both trabecular and cortical compartments of the distal tibia in the TCC group as compared with the controls, as measured by pQCT. A total of 4 fracture cases were documented during follow-up, including 3 subjects in the control group and 1 in the TCC group. CONCLUSIONS: This is the first prospective and randomized study to show that a programmed TCC exercise intervention is beneficial for retarding bone loss in weight-bearing bones in early postmenopausal women. Long-term follow-up is needed to substantiate the role of TCC exercise in the prevention of osteoporosis and its related fracture.

Asian People↗

Parathyroid hormone: a double-edged sword for bone metabolism.

Parathyroid hormone (PTH) is the major hormone regulating calcium metabolism. It is also the only FDA-approved drug for osteoporosis treatment that stimulates bone formation when injected daily. However, continuous infusion of PTH causes severe bone loss in line with its known catabolic effects. Many studies to understand the dual effects of PTH have been carried out, and in recent years a growing number of molecular and cellular mechanisms underlying these effects have emerged. Here, we outline the present knowledge and conclude that the kinetics of administration and subsequent signaling probably account for the divergent actions of the hormone.

Bone Density↗

Lack of efficacy of low-intensity pulsed ultrasound on prevention of postmenopausal bone loss evaluated at the distal radius in older Chinese women.

A within-subject, randomized, and prospective intervention trial was done to evaluate the potential effect of low-intensity pulsed ultrasound on prevention of postmenopausal bone loss. Twenty healthy postmenopausal women between the ages of 51-81 years met the inclusion criteria. The treatment hand was randomly selected, and the contralateral site served as a control. Integral and trabecular bone mineral density were measured using highly precise multilayer peripheral quantitative computed tomography at the bilateral distal radius at baseline, 3 months after daily low-intensity pulsed ultrasound treatment, and 3 months after discontinuing treatment. Results showed that the rate of bone change (trabecular bone mineral density and integral bone mineral density) did not significantly differ between the site treated with low-intensity pulsed ultrasound and the contralateral control at either followup. Also, during the followup, bone mineral density did not change significantly in the contralateral control site. This was the first prospective and randomized study to show that low-intensity pulsed ultrasound at the current regime did not have significant effects on intact bone for prevention of postmenopausal bone loss in the distal radii of older Chinese women.

Aged↗

Mass spectrometric detection of protein, lipid and heme components of cytochrome c oxidase from R. sphaeroides and the stabilization of non-covalent complexes from the enzyme.

The cytochrome c oxidase enzyme from the Rhodobacter sphaeroides bacteria exists as a complex of four peptide subunits, two hemes, and a variety of lipids and metal ions held together by non-covalent forces. While the native enzyme functions as an associated unit, this complex usually dissociates during MALDI- TOF analysis. Through the use of matrix additives such as sucrose, the complete complex and partial complexes can be stabilized in the MALDI-TOF experiment. The dissociation of the complex allows for the detection of the components of the enzyme. The direct detection of associated lipids from an aqueous solution of the intact enzyme may eliminate the need for enzyme disruption and lipid extraction. The partial dissociation of multisubunit enzymes in such experiments may allow for the determination of subunit-subunit and subunit-lipid interactions

Amino Acid Sequence↗