Lateral osteoperiosteal flap versus lateral pedicle flap in the treatment of class III gingival recession: A single-center, open-label trial

AIMS

The aim of this study was to compare outcomes of lateral osteoperiosteal flap (OPF) and lateral pedicle flap (LPF) in the treatment of Miller's Class III gingival recession.

MATERIALS AND METHODS

Twenty-two anterior maxillary and mandibular sites from 16 participants requiring mucogingival surgery for Miller's Class III gingival recession were included in the study. Eleven sites each were assigned to two groups. OPF: sites treated with lateral OPF and LPF: sites treated with LPF. Recession depth (RD) and bone level (BL) were the primary outcome variables, and probing pocket depth, clinical attachment level (CAL), and keratinized tissue width (KTW) were the secondary variables. All the variables were recorded at baseline (on the day of surgery), 3 months, and 6 months postsurgery.

RESULTS

OPF and LPF resulted in similar reduction in RD at the end of the study period (P ≤ 0.001). There was no statistically significant difference in RD between OPF and LPF at 6 months (P = 0.862). OPF-treated sites showed greater gain in BL at 3 months (P = 0.0004) and 6 months (P = 0.0002). No significant differences were seen between OPF and LPF in measures of PD, CAL, and KTW.

CONCLUSION

Data from this 6-month trial seem to suggest that OPF can be used as an alternative procedure for treating Miller's class III recessions with adjacent edentulous sites or wide interproximal spaces. Long-term effects of OPF on the stability of root coverage outcomes are an exciting direction for future research.

Structural insights into the ene-reductase synthesis of profens

Reduction of double bonds of α,β-unsaturated carboxylic acids and esters by ene-reductases remains challenging and it typically requires activation by a second electron-withdrawing moiety, such as a halide or second carboxylate group. We showed that profen precursors, 2-arylpropenoic acids and their esters, were efficiently reduced by Old Yellow Enzymes (OYEs). The XenA and GYE enzymes showed activity towards acids, while a wider range of enzymes were active towards the equivalent methyl esters. Comparative co-crystal structural analysis of profen-bound OYEs highlighted key interactions important in determining substrate binding in a catalytically active conformation. The general utility of ene reductases for the synthesis of (R)-profens was established and this work will now drive future mutagenesis studies to screen for the production of pharmaceutically-active (S)-profens.

Acute rejection following lung transplantation: limitations in accuracy of thin-section CT for diagnosis

PURPOSE

To evaluate the sensitivity, specificity, predictive values, and accuracy of thin-section computed tomography (CT) for the diagnosis of acute rejection following lung transplantation and to determine whether any individual CT abnormalities are associated with histopathologically proved acute rejection.

MATERIALS AND METHODS

Thin-section CT studies from 64 lung transplant recipients were retrospectively reviewed. CT studies were temporally correlated with various grades of biopsy-proved acute rejection (n = 34); 30 other CT studies were from a control group with no histopathologic evidence of acute rejection. Acute rejection was diagnosed as present or absent, and the diagnostic was calculated.

RESULTS

The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CT for the diagnosis of acute rejection were as follows: 35%, 73%, 60%, 50%, 53%, respectively. No individual CT finding was significantly associated with acute rejection. The sensitivity of CT for the detection of various grades of acute rejection was 17% for grade A1, 50% for grade A2, and 20% for grade A3. The combination of volume loss and septal thickening, with or without pleural effusion, was never seen in the absence of acute rejection.

CONCLUSION

Thin-section CT has limited accuracy for the diagnosis of acute rejection following lung transplantation, and no individual CT finding is significantly associated with this diagnosis.

Comparison between MR imaging and 99mTc MIBI scintigraphy in the evaluation of recurrent of persistent hyperparathyroidism

PURPOSE

To compare the sensitivity and positive predictive value of magnetic resonance (MR) imaging and technetium 99m 2-methoxyisobutyl-isonitrile (MIBI) scintigraphy for the detection of hyperfunctioning parathyroid tissue when used alone and in combination in a large patient population with recurrent or persistent hyperparathyroidism (HPT).

MATERIALS AND METHODS

In 98 consecutive patients with biochemically proved recurrent or persistent HPT after surgery, MR imaging and 99mTc MIBI study findings were retrospectively reviewed and compared with surgical and histopathologic findings. The sensitivity and positive predictive value of MR imaging and 99mTc MIBI scintigraphy were compared with each other and in combination.

RESULTS

In these patients, 130 abnormal parathyroid glands were identified at surgery. The sensitivity and positive predictive value of MR imaging were 82% (95% CI: 75%, 89%) and 89%, respectively; those for (99m)Tc MIBI scintigraphy were 85% (95% CI: 79%, 91%) and 89%. No significant difference was found between MR imaging and 99mTc MIBI scintigraphy for sensitivity (P =.7). The sensitivity and positive predictive value for the detection of abnormal parathyroid tissue on a per-gland basis increased to 94% (95% CI: 90%, 98%) and 98%, respectively, when only one of the two tests was required to be positive.

CONCLUSION

MR imaging and 99mTc MIBI scintigraphy have similarly good sensitivity and positive predictive value for the detection of hyperfunctioning parathyroid tissue in patients after surgery. The combination of the two tests provided a substantial increase in sensitivity and positive predictive value.

Identification of pulmonary vein stenosis after radiofrequency ablation for atrial fibrillation using MRI

Pulmonary vein stenosis is one of the frequent complications after radiofrequency ablation for atrial fibrillation. MRI plays an important role in depicting the pathoanatomic structure of the pulmonary veins, and measuring the blood flow velocity in the pulmonary veins before and after therapy, and is superior to transesophageal echocardiography for this purpose.

Early bronchiolitis obliterans following lung transplantation: accuracy of expiratory thin-section CT for diagnosis

PURPOSE

To evaluate the accuracy of thin-section computed tomography (CT) with expiratory scans in diagnosing early bronchiolitis obliterans after lung transplantation.

MATERIALS AND METHODS

Thin-section CT scans were reviewed by two observers blinded to the diagnoses in seven consecutive lung transplant recipients with histopathologically proved bronchiolitis obliterans (group A) and 21 with normal biopsy findings (group B). All patients had normal biopsy and stable pulmonary function test (PFT) results 2-36 weeks prior to CT. Patients with normal biopsy results were placed into subgroups based on abnormal (group B1) or stable (group B2) PFT results. Air-trapping extent on expiratory scans was scored on a 24-point scale.

RESULTS

The mean air-trapping score in group A (6.6) was not significantly different from that in group B (4.5, P =. 17). The air-trapping score was significantly higher in groups A and B1 than in group B2 (6.2 and 2.6, respectively; P =.03). The frequency of an air-trapping score of 3 or more in groups A and B1 was significantly higher than that in group B2 (P =.03). By using a score of 3 or more to indicate air trapping, the sensitivity of expiratory CT was 74%, specificity was 67%, and accuracy was 71%.

CONCLUSION

Thin-section CT, including expiratory scans, is of limited accuracy in diagnosing early bronchiolitis obliterans after lung transplantation.

Low-dose, dynamic, expiratory thin-section CT of the lungs using a spiral CT scanner

Seventeen patients with lung transplants were evaluated with inspiratory, postexpiratory, and low-dose, dynamic expiratory thin-section computed tomography (CT). Region of interest measurements were performed on inspiration and expiration images with both techniques, and mean lung attenuation changes between inspiration and expiration images were calculated and compared. Dynamic expiratory thin-section CT resulted in a significantly greater increase in lung attenuation than postexpiratory thin-section CT. Dynamic expiratory thin-section CT may prove useful in the evaluation of patients with lung diseases characterized by air flow obstruction with little increase in patient radiation dose.

Incidental detection of thoracic sarcoidosis on whole-body 18fluorine-2- fluoro-2-deoxy-D-glucose positron emission tomography

18 Fluorine-2- Fluoro-2-Deoxy-D-Glucose positron emission tomography (18FDG PET) allows imaging of sites with increased metabolic activity. Increased metabolic activity in mediastinal nodes in sarcoidosis has been described. We report the prospective diagnosis of thoracic sarcoidosis on 18FDG PET based on extensive, peripheral, upper lobe parenchymal, and mediastinal nodal tracer uptake.

Three-dimensional MR imaging of pulmonary vessels and parenchyma with NC100150 injection (Clariscan)

The influence of increasing doses of NC100150 Injection (Clariscantrade mark) and echo times on visualization of pulmonary vessels and parenchyma was evaluated. The effects of 0.5, 1, 2, 4, and 8 mg Fe/kg NC100150 Injection and echo times (TE) of 1.1, 1.8, 2. 2, and 4.3 msec were determined in six dogs using breath-hold three-dimensional (3D) spoiled gradient-echo magnetic resonance (MR) sequence. At 2 mg Fe/kg and TE of 1.1 msec, the signal-to-noise ratio of the central pulmonary arteries and parenchyma was significantly increased (5.3 +/- 2.2 to 50.3 +/- 2.4) and (2.2 +/- 0. 9 to 6.4 +/- 1.1), respectively. Using the TE of 1.1 msec, signal intensity in the main arteries continued to increase with increasing dose. Moreover, the enhancement of pulmonary parenchyma and microvasculature had a positive dose response. 3D MR imaging with ultrashort echo time and 2 mg Fe/kg NC100150 Injection produces angiograms with strong vascular contrast and allows qualitative assessment of pulmonary parenchyma and microvasculature.

MR imaging of the thoracic aorta

MR imaging is an effective modality for noninvasive morphologic and functional assessment of the thoracic aorta. MR imaging provides several advantages for vascular imaging, including intrinsic contrast between the blood pool and vascular structures, multiplanar imaging capability, and the absence of ionizing radiation. By combining imaging and flow-sensitive techniques, MR imaging can be used to delineate morphology and to quantify bloodflow volume and velocity. In patients who need sequential examinations over time to monitor disease severity, a noninvasive technique such as MR imaging is desirable.

Multiple pulmonary nodules in AIDS: usefulness of CT in distinguishing among potential causes

PURPOSE

To determine whether the computed tomographic (CT) appearances of multiple pulmonary nodules in patients with acquired immunodeficiency syndrome (AIDS) can help differentiate the potential infectious and neoplastic causes.

MATERIALS AND METHODS

The thoracic CT scans obtained in 60 patients with AIDS and multiple pulmonary nodules were reviewed retrospectively by two thoracic radiologists who were blinded to clinical and pathologic data. The scans were evaluated for nodule size, distribution, and morphologic characteristics. CT findings were correlated with final diagnoses.

RESULTS

Thirty-six (84%) of 43 patients with opportunistic infection had a predominance of nodules smaller than 1 cm in diameter, whereas 14 (82%) of 17 patients with a neoplasm had a predominance of nodules larger than 1 cm (P <.001). Of the 43 patients with opportunistic infection, 28 (65%) had a centrilobular distribution of nodules; only one (6%) of 17 patients with a neoplasm had this distribution (P <.001). Seven (88%) of eight patients with a peribronchovascular distribution had Kaposi sarcoma (P <.001).

CONCLUSION

In patients with AIDS who have multiple pulmonary nodules at CT, nodule size and distribution are useful in the differentiation of potential causes. Nodules smaller than 1 cm, especially those with a centrilobular distribution, are typically infectious. Nodules larger than 1 cm are often neoplastic. A peribronchovascular distribution is suggestive of Kaposi sarcoma.

Imaging evaluation of suspected pulmonary embolism

Venous thromboembolism (VTE) is a common disorder that is difficult to diagnose clinically but carries significant morbidity and mortality if untreated. Additionally, although demonstrated to be of benefit in cases of proven deep vein thrombosis (DVT) and pulmonary embolism (PE), anticoagulation therapy is not without risk. Because the clinical exam is known to be unreliable for the detection of both DVT and PE, many imaging modalities have been used in the diagnostic imaging algorithm for the detection of VTE, including chest radiography, ventilation/perfusion (V/Q) scintigraphy, pulmonary angiography, and recently, spiral computed tomography (CT) and magnetic resonance imaging (MRI). Chest radiographic findings in acute PE include focal oligemia, vascular enlargement, atelectasis, pleural effusions, and air space opacities representing pulmonary hemorrhage or infarction. The chest radiograph can occasionally be suggestive of PE but is more often nonspecifically abnormal. The main use of the chest radiograph in the evaluation of suspected PE is to exclude entities that may simulate PE and to assist in the interpretation of V/Q scintigraphy. Lower extremity venous compression ultrasonography (CU) is both sensitive and specific for the diagnosis of femoropopliteal DVT, and the value of negative CU results has been established in outcomes studies. However, the reliability of CU for the detection of isolated calf vein thrombosis is not well established, and the clinical significance of such thrombi is debatable. Additional methods such as color and spectral Doppler analysis are also useful in the diagnostic evaluation of DVT but are best considered as adjuncts to the conventional CU examination rather than as primary diagnostic modalities themselves. Compression ultrasonography and Doppler techniques are useful in the evaluation of suspected upper extremity DVT; spectral Doppler waveform analysis is particularly useful to assess for the patency of veins that cannot be directly visualized and compressed with conventional gray-scale sonography. V/Q scintigraphy has been the initial modality obtained in patients suspected of PE for a number of years. Although many studies have investigated the role of V/Q scintigraphy in the evaluation of VTE, the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) study has provided the most useful information regarding the utility of V/Q scintigraphy in this setting. A high probability scan interpretation is sufficient justification to institute anticoagulation, and a normal perfusion scan effectively excludes the diagnosis of PE. A normal/near normal scan interpretation also carries a sufficiently low prevalence of angiographically proven PE to withhold anticoagulation. Although the prevalence of PE in the setting of low probability scan interpretations is low and several outcomes studies have demonstrated a benign course in untreated patients with low probability scan results, patients with inadequate cardiopulmonary reserve do not necessarily have good outcomes. Such patients deserve more aggressive evaluation. Patients with intermediate probability scan results have a 20% to 40% prevalence of angiographically proven PE and thus require further investigation. The radionuclide investigation of DVT includes such techniques as radionuclide venography and thrombus-avid scintigraphy. Although these methods have not been as thoroughly evaluated as CU, studies thus far have indicated encouraging results, and further investigations are warranted. Pulmonary angiography has been the gold standard for the diagnosis of PE for decades. Studies have indicated that angiography has probably been underutilized by referring physicians for the evaluation of suspected PE, likely because of the perception of significant morbidity and mortality associated with the procedure. (ABSTRACT TRUNCATED)

Aneurysm of saphenous vein coronary bypass graft: diagnosis by computed tomography

A patient with a history of coronary artery bypass graft surgery underwent computed tomography scanning for evaluation of a lung mass. A heterogeneous mediastinal mass discovered incidentally on computed tomography scanning was shown to be a saphenous vein bypass graft aneurysm.

MRI of supracristal ventricular septal defects

The MR features of two cases of supracristal ventricular septal defect are described. In both patients, axial SE T1-weighted images demonstrated a defect between the base of the aorta and the upper posterior aspect of the right ventricular infundibulum. Cine MRI in the two cases showed left-to-right shunting with a flow jet in the distal right ventricular outflow tract that propagated into the main pulmonary artery. Both patients had prolapse of the right sinus of Valsalva, and one had aortic insufficiency.

Congenital heart disease: measuring physiology with MRI

Cine MRI and VEC MRI can be used to quantitate the physiology of the heart and great vessels in patients with CHD. This information can be a valuable adjunct to anatomical imaging for preoperative planning as well as postoperative monitoring. Some important clinical applications of quantitative cardiovascular functional MRI include measurement of ventricular masses, stroke volumes, and ejection fractions; estimation of shunts and valvular regurgitation; assessment of collateral blood flow and pressure gradients in aortic coarctation; and postsurgical evaluation of conduit blood flow and pressure gradients.

Structure determination of the capsular polysaccharide from Vibrio vulnificus strain 6353

Vibrio vulnificus is a pathogenic gram-negative bacterium, endemic to brackish waters, which is often isolated from sediments, from the water column or from shellfish. It is associated with wound infections and septicemia in humans and the virulence of V. vulnificus has been strongly associated with encapsulation. The capsular polysaccharide purified from a virulent strain of V. vulnificus 6353 did not show cross reactivity with antibodies to the capsular polysaccharide of a related pathogenic strain of V. vulnificus (MO6-24) the structure of which was recently reported. NMR spectroscopic analysis of the purified polysaccharide from strain 6353 showed that the polymer is composed of four sugar residues per repeating subunit including 2,6-dideoxy-2-N-acetylamino-alpha-D-glucose (QuiNAc), 2-deoxy-2-N-acetylamino-alpha-D-galactose (alpha-D-GalNAc), 2-deoxy-2-N-acetylamino-alpha-D-galcturonic acid (alpha-D-GalNAcA) and 2-N-acetylamino-alpha-D-glucuronamide (alpha-D-GlcNAcANH2). The 1H- and 13C-NMR spectra were completely assigned by homonuclear and heteronuclear NMR spectroscopy. Sugar types and anomeric configurations were determined from proton homonuclear coupling constants and glycosidic linkages were determined from 1H-13C heteronuclear multiple bond correlation spectra. Sugar identities were confirmed by high performance anion-exchange chromatography and absolute configurations were determined by gas chromatography in combination with molecular modeling and NMR spectroscopy. The structure of the polysaccharide repeating unit is: [-->4)-alpha-D-GalpNAc-(1-->3)-alpha-D-GalpNAcA-(1-->3)-alpha-D-++ +QuipNAc-(1-->]n alpha-D-GlcpNAcANH2 (1-->4)- -->. While there are some common features shared among the structures of the capsular polysaccharides of pathogenic strains of V. vulnificus, there are distinct differences in the detailed structures.

Coronary artery stenoses: assessment with contrast-enhanced electron-beam CT and axial reconstructions

PURPOSE

To evaluate the usefulness of electron-beam computed tomography (CT) for identification of coronary artery stenoses.

MATERIALS AND METHODS

Coronary angiography and contrast material-enhanced, electrocardiographically triggered electron-beam CT of the heart were performed in 23 patients. With axial CT images and axial maximum intensity projection reconstructions, the coronary arteries were assessed by two observers blinded to the results of angiography.

RESULTS

Cardiac motion artifact (unsharpness) precluded evaluation of the right coronary artery (RCA) in six subjects and the left circumflex coronary artery (LCX) in one patient. With the vessels degraded by motion artifact eliminated from analysis, overall sensitivity of electron-beam CT for hemodynamically significant stenoses was 88%, and specificity was 79%. In the left anterior descending coronary artery (LAD), sensitivity was 93% and specificity was 63%; in the LCX, sensitivity was 100% and specificity was 67%; and in the RCA, sensitivity was 67% and specificity was 77%. The presence of coronary artery calcification did not have an effect on sensitivity for stenoses, but it did decrease specificity.

CONCLUSION

Electron-beam CT angiography can depict hemodynamically significant stenoses in the LAD and LCX with a sensitivity of more than 90%. The presence of coronary artery calcification resulted in decreased specificity but no appreciable change in sensitivity.

Structure of a muramic acid containing capsular polysaccharide from the pathogenic strain of Vibrio vulnificus ATCC 27562

Vibrio vulnificus strains isolated from septicemia cases and from the environment show a wide variety of capsular types. In an attempt to find common structural features which can be correlated with pathogenicity and toxicity, we have determined structures of the capsular polysaccharides (CPS) from several pathogenic strains. We report the complete structure of the polysaccharide from the pathogenic V. vulnificus strain ATCC 27562 using a combination of homonuclear and heteronuclear one-dimensional and two dimensional NMR experiments. The 13C and 1H NMR spectra, including the exchangeable amide proton resonances, have been completely assigned. The amide linkage between Ser and C6 of GalA has been unambiguously determined by water-suppressed 2D NOESY. To verify the structure established by NMR, we have fragmented the polymer employing the Smith degradation procedure. The Smith product identified by NMR and matrix-assisted laser desorption mass spectrometry is consistent with the proposed structure for the CPS, which is composed of D-GlcNAc, MurNAc, D-GalA, L-Rha and is serine-linked as shown: [formula: see text]

Esophageal compression by the aorta after arterial switch

Extrinsic compression of the esophagus in children most often occurs in the presence of a congenital vascular ring. We recently operated on a patient in whom esophageal compression had developed that was severe enough to require feeding via a gastrostomy tube several years after the arterial switch operation. Aortopexy and extensive mediastinal mobilization were performed twice with transient relief and gradual return of symptoms. Almost 3 years after the first aortopexy, lasting relief was achieved by transposing the esophagus into the right side of the chest.

Structural and antigenic types of cell wall polysaccharides from viridans group streptococci with receptors for oral actinomyces and streptococcal lectins

Lectin-mediated interactions between oral viridans group streptococci and actinomyces may play an important role in microbial colonization of the tooth surface. The presence of two host-like motifs, either GalNAc beta1-->3Gal (Gn) or Gal beta1-->3GalNAc (G), in the cell wall polysaccharides of five streptococcal strains accounts for the lactose-sensitive coaggregations of these bacteria with Actinomyces naeslundii. Three streptococcal strains which have Gn-containing polysaccharides also participate in GalNAc-sensitive coaggregations with strains of Streptococcus gordonii and S. sanguis. Each Gn- or G-containing polysaccharide is composed of a distinct phosphodiester-linked hexa- or heptasaccharide repeating unit. The occurrence of these polysaccharides on 19 additional viridans group streptococcal strains that participate in lactose-sensitive coaggregations with actinomyces was examined. Negatively charged polysaccharides that reacted with Bauhinia purpurea agglutinin, a Gal and GalNAc binding plant lectin, were isolated from 17 strains by anion exchange column chromatography of mutanolysin-cell wall digests. Results from nuclear magnetic resonance and immunodiffusion identified each of 16 polysaccharides as a known Gn- or G-containing structural type and one polysaccharide as a new but closely related Gn-containing type. Unlike the reactions of lectins, the cross-reactions of most rabbit antisera with these polysaccharides were correlated with structural features other than the host-like motifs. Gn-containing polysaccharides occurred primarily on the strains of S. sanguis and S. oralis while G-containing polysaccharides were more common among the strains of S. gordonii and S. mitis examined. The findings strongly support the hypothesis that lectin-mediated recognition of these streptococci by other oral bacteria depends on a family of antigenically diverse Gn- and G-containing cell wall polysaccharides, the occurrence of which may differ between streptococcal species.

Cell cycle analysis and synchronization of pluripotent hematopoietic progenitor stem cells

Hematopoietic stem cells purified from mouse bone marrow are quiescent with less than 2% of Lin- Hoechst(low)/Rhodamine(low) (Lin- Ho(low)/Rho(low)) and 10% to 15% of Lin-/Sca+ cells in S phase. These cells enter proliferative cycle and progress through G1 and into S phase in the presence of cytokines and 5% heat-inactivated fetal calf serum (HI-FCS). Cytokine-stimulated Lin- Ho(low)/Rho(low) cells took 36 to 40 hours to complete first division and only 12 hours to complete each of 5 subsequent divisions. These cells require 16 to 18 hours to transit through G0/G1 period and 28 to 30 hours to enter into mid-S phase during the first cycle. Up to 56% of Lin- Rho(low)/Ho(low) cells are high-proliferative potential (7 factor-responsive) colony-forming cells (HPP-CFC). At isolation, HPP-CFC are quiescent, but after 28 to 30 hours of culture, greater than 60% are in S phase. Isoleucine-deprivation of Lin- Ho(low)/Rho(low) cells in S phase of first cycle reversibly blocked them from entering into second cycle. After the release from isoleucine-block, these cells exhibited a G1 period of less than 2 hours and entered into mid-S phase by 12 hours. Thus, the duration of G1 phase of the cells in second cycle is 4 to 5 times shorter than that observed in their first cycle. Similar cell cycle kinetics are observed with Lin-/Sca+ population of bone marrow cells. Stem cell factor (SCF) alone, in the presence of HI-FCS, is as effective as a cocktail of 2 to 7 cytokines in inducing quiescent Lin-/Sca+ cells to enter into proliferative cycle. Aphidicolin treatment reversibly blocked cytokine-stimulated Lin-/Sca+ cells at G1/S boundary, allowing their tight synchrony as they progress through first S phase and enter into second G1. For these cells also, SCF alone is sufficient for their progression through S phase. These studies indicate a very short G1 phase for stem cells induced to proliferate and offer experimental approaches to synchronize murine hematopoietic stem cells.

Expression of basic helix-loop-helix transcription factors in explant hematopoietic progenitors

The basic helix-loop-helix (bHLH) transcription factors form heterodimers and control steps in cellular differentiation. We have studied four bHLH transcription factors, SCL, lyl-1, E12/E47, and ld-1, in individual lineage-defined progenitors and hematopoietic growth factor-dependent cell lines, evaluating mRNA expression and the effects of growth factors and cell cycle phase on this expression. Single lineage-defined progenitors selected from early murine colony starts and grown under permissive conditions were analyzed by RT-PCR. SCL and E12/E47 were expressed in the vast majority of tri-, bi-, and unilineage progenitors of erythroid, macrophage, megakaryocyte, and neutrophil lineages. Expression for E12/E47 was not seen in unilineage megakaryocyte and erythroid or bilineage neutrophil/mast cell progenitors. Lyl-1 showed a more restricted pattern of expression, although expression was seen in some bi- and unilineage progenitors. No expression was detected in erythroid, erythroid-megakaryocyte-macrophage, macrophage-neutrophil, macrophage, or megakaryocytic progenitors. Id-1, an inhibitory bHLH transcription factor, was also widely expressed in all bi- and unilineage progenitors; only the trilineage erythroid-megakaryocyte-macrophage progenitors failed to show expression. Expression of these factors within a progenitor class was generally heterogeneous, with some progenitors showing expression and some not. This was seen even when two sister cells from the same colony start were analyzed. Id-1, but not E12/E47, mRNA was increased in FDC-P1 and MO7E hematopoietic cell lines after exposure to IL-3 or GM-CSF. Id-1, E12, and lyl-1 showed marked variation at different points in cell cycle in isoleucine-synchronized FDC-P1 cells. These results suggest that SCL, lyl-1, E12/E47, and Id-1 are important in hematopoietic progenitor cell regulation, and that their expression in hematopoietic cells varies in response to cytokines and/or during transit through cell cycle.

Stem cell factor enhances interleukin-3 dependent induction of 68-kD calmodulin-binding protein and thymidine kinase activity in NFS-60 cells

Stem cell factor (SCF) is known to act synergistically with other hematopoietic factors in increasing the colony formation of hematopoietic progenitor cells. We have shown that interleukin-3 (IL-3)-dependent proliferation of NFS-60 cells is associated with the induction of a specific calmodulin-binding protein of about 68 kD (CaM-BP68). To evaluate the relationship between proliferative stimulation and the induction of CaM-BP68 by cytokines, we examined whether the increased proliferative potential of NFS-60 cells in response to SCF is reflected in an increased induction of the CaM-BP68. We observed that SCF alone has a limited effect on proliferative stimulation and on the induction of CaM-BP68 in factor-deprived NFS-60 cells. However, when combined with IL-3, granulocyte colony-stimulating factor (G-CSF), or IL-6, it caused a significant increase in cytokine-dependent proliferative stimulation, as well as in the induction of CaM-BP68. Furthermore, an increase in IL-3-dependent induction of CaM-BP68 in the presence of SCF coincided with a corresponding increase in thymidine kinase activity, whose expression is linked to G1/S transition of the cells. At low concentrations SCF caused a synergistic increase in IL-3-dependent induction of both CaM-BP68 and thymidine kinase activity. In contrast to the changes in CaM-BP68 and thymidine kinase activity, no significant changes in DNA polymerase alpha were observed in factor-deprived NFS-60 cells in response to IL-3 and/or SCF. These observations suggest an increased expression of CaM-BP68 and thymidine kinase are associated with the synergistic effect of SCF on factor-dependent proliferation of hematopoietic progenitor cells.

Cytokine induction of proliferation and expression of CDC2 and cyclin A in FDC-P1 myeloid hematopoietic progenitor cells: regulation of ubiquitous and cell cycle-dependent histone gene transcription factors

To evaluate transcriptional mechanisms during cytokine induction of myeloid progenitor cell proliferation, we examined the expression and activity of transcription factors that control cell cycle-dependent histone genes in interleukin-3 (IL-3)-dependent FDC-P1 cells. Histone genes are transcriptionally upregulated in response to a series of cellular regulatory signals that mediate competency for cell cycle progression of the G1/S-phase transition. We therefore focused on factors that are functionally related to activity of the principal cell cycle regulatory element of the histone H4 promoter: CDC2, cyclin A, as well as RB- and IRF-related proteins. Comparisons were made with activities of ubiquitous transcription factors that influence a broad spectrum of promoters independent of proliferation or expression of tissue-specific phenotypic properties. Northern blot analysis indicates that cellular levels of cyclin A and CDC2 mRNAs increase when DNA synthesis and H4 gene expression are initiated, supporting involvement in cell cycle progression. Using gel-shift assays, incorporating factor-specific antibody and oligonucleotide competition controls, we define three sequential period following cytokine stimulation of FDC-P1 cells when selective upregulation of a subset of transcription factors is observed. In the initial period, the levels of SP1 and HiNF-P are moderately elevated; ATF, AP-1, and HiNF-M/IRF-2 are maximal during the second period; while E2F and HiNF-D, which contain cyclin A as a component, predominate during the third period, coinciding with maximal H4 gene expression and DNA synthesis. Differential regulation of H4 gene transcription factors following growth stimulation is consistent with a principal role of histone gene promoter elements in integrating cues from multiple signaling pathways that control cell cycle induction and progression. Regulation of transcription factors controlling histone gene promoter activity within the context of a staged cascade of responsiveness to cyclins and other physiological mediators of proliferation in FDC-P1 cells provides a paradigm for experimentally addressing interdependent cell cycle and cell growth parameters that are operative in hematopoietic stem cells.

Lectin recognition of host-like saccharide motifs in streptococcal cell wall polysaccharides

Viridans streptococci that participate in the microbial colonization of teeth have cell wall polysaccharides composed of linear phosphodiester-linked hexa- or heptasaccharide repeating units, each containing a host-like disaccharide motif, either Gal beta 1-->3GalNAc or GalNAc beta 1-->3Gal. Whereas strains with GalNAc beta 1-->3Gal-containing polysaccharides co-aggregated with streptococci that possess GalNAc-sensitive lectins, strains with either host-like motif co-aggregated with Actinomyces spp. The latter interactions reflected the specificity of Actinomyces spp. lectins for common features of Gal beta 1-->3GalNAc and GalNAc beta 1-->3Gal. Thus, alpha-linked glycosides of both disaccharides were much more potent inhibitors of co-aggregation than Gal or GalNAc. Six non-bacterial lectins also reacted with the streptococcal polysaccharides. In general, precipitation of each lectin with each polysaccharide involved binding of Gal or GalNAc within the host-like motifs, but not saccharides outside these regions. The lectins of Ricinus communis, Abrus precatorius, Codium fragile and Agaricus bisporus were most reactive with the Gal beta 1-->3GalNAc-containing polysaccharides, the Wisteria floribunda lectin with the GalNAc beta 1-->3Gal-containing polysaccharides and the Bauhinia purpurea lectin with polysaccharides containing either disaccharide. Thus, lectin recognition of the streptococcal cell wall polysaccharides involved either the common or specific sides of the Gal beta 1-->3GalNAc and GalNAc beta 1-->3Gal motifs present within these molecules.

The 68 kDa calmodulin-binding protein is tightly associated with the multiprotein DNA polymerase alpha-primase complex in HeLa cells

Calcium and its receptor protein calmodulin function in the regulation of proliferation of mammalian cells. A 68 kDa calmodulin-specific binding protein was shown previously to be associated with growth factor-dependent progression of a variety of mammalian cells from G1 to S phase and to stimulate DNA synthesis in permeabilized hematopoietic progenitor cells. In this report we show that the 68 kDa calmodulin-specific binding protein in HeLa cells is tightly associated with the DNA polymerase alpha-primase component of the 21S complex of enzymes for DNA synthesis. The 68 kDa calmodulin-binding protein and the DNA polymerase alpha-primase complex cofractionate during Q-Sepharose chromatography to isolate the 21S enzyme complex, native and denatured DNA-cellulose to dissociate the 21S complex, and DEAE-Bio-Gel chromatography to isolate the multiprotein DNA polymerase alpha-primase complex. The 68 kDa calmodulin-specific binding protein and DNA polymerase alpha also bind and coelute during affinity chromatography on calmodulin-agarose. They also coprecipitate with C10-agarose-linked monoclonal antibody SJK 132-20 to human DNA polymerase alpha. The tight association of the 68 kDa calmodulin-binding protein to the DNA polymerase alpha-primase complex supports a function for this protein in the regulation of DNA synthesis in vivo.

Preliminary structure determination of the capsular polysaccharide of Vibrio cholerae O139 Bengal Al1837

Vibrio cholerae O139 Bengal has recently been identified as a cause of epidemic cholera in Asia. In contrast to V. cholerae O1, V. cholerae O139 Bengal has a polysaccharide capsule. As determined by high-performance anion-exchange chromatography and 1H nuclear magnetic resonance analysis, the capsular polysaccharide of V. cholerae O139 Bengal strain Al1837 has six residues in the repeating subunit; this includes one residue each of N-acetylglucosamine, N-acetylquinovosamine (QuiNAc), galacturonic acid (GalA), and galactose and two residues of 3,6-dideoxyxylohexose (Xylhex). The proposed structure is [formula: see text]

Growth factor modulated calmodulin-binding protein stimulates nuclear DNA synthesis in hemopoietic progenitor cells

A specific calmodulin-binding protein of 68 kDa (CaM-BP68) is modulated in response to growth factors that induce proliferative stimulation in a variety of hemopoietic progenitor cells. The nuclear localization of the CaM-BP68 coincided temporally with interleukin 3 (IL-3)-dependent progression of synchronized FDC-P1 cells from G1 to S phase [Reddy et al. (1992) Blood 79, 1946-1956]. To delineate the role of the CaM-BP68 in the onset of DNA synthesis (S phase), this protein was purified to an apparent homogeneity from FDC-P1 cells and its effects on DNA replication in permeabilized FDC-P1 cells were examined. Purified CaM-BP exhibited a single silver-stained protein band of 68 kDa on SDS-polyacrylamide gels. This purified protein, when incubated with permeabilized log-growing FDC-P1 cells, caused a 3-4-fold increase in the rate of [3H]dTTP incorporation into DNA as compared to the controls. There was a direct correlation between the increase in the rate of [3H]dTTP incorporation into DNA and the concentration of the added CaM-BP68 in the incubation mixture. These observations suggest that the CaM-BP68, whose nuclear localization is associated with growth factor dependent proliferative stimulation of myeloid progenitor cells, is involved in the regulation of nuclear DNA synthesis.

Cell cycle: regulatory events in G1-->S transition of mammalian cells

A cell divides into two daughter cells by progressing serially through the precisely controlled G1, S, G2, and M phases of the cell cycle. The crossing of the G1/S border, which is marked by the initiation of DNA synthesis, represents commitment to division into two complete cells. Beyond this critical point no further external signals are required. We now have more comprehensive knowledge of the temporal sequence of systems at this key transition from G1 to S--growth factor responses, a cascade of kinase reactions, activation of cyclins and their associated kinases, and oncogene and tumor suppressor gene products. Furthermore, we know that the absolute requirement for calcium and the timing of events associated with calmodulin and the 68 kDa calmodulin-binding protein are consistent with overall Ca++/calmodulin control of all steps from the response to growth factors in G1 to DNA replication in S phase. We now have to sort out the inter-relationships of myriad control proteins and their relation to the Ca++/calmodulin-dependent controls--Which are causes? Which are effects? And which are parallel processes? The answers will be important, as they represent both a much deeper understanding of this key process of life and an important opportunity for improving therapeutic medicine.

The cell wall polysaccharide of Streptococcus gordonii 38: structure and immunochemical comparison with the receptor polysaccharides of Streptococcus oralis 34 and Streptococcus mitis J22

As part of our ongoing investigations involving lectin-mediated adhesion among oral bacteria, the receptor polysaccharide from Streptococcus gordonii 38 was isolated and characterized. Carbohydrate analysis of the hydrolysed S. gordonii 38 polysaccharide by high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) showed galactose (Gal) (2 mol), N-acetylgalactosamine (GalNAc) (1 mol), rhamnose (Rha) (2 mol), glucose (Glc) (1 mol) and galactosamine-6-phosphate (1 mol). Mild acid hydrolysis of the polysaccharide yielded a heptasaccharide repeating unit. The structure of the heptasaccharide repeating unit was determined by high-resolution NMR spectroscopy which includes various homonuclear (DQF-COSY, TQF-COSY, NOESY and HOHAHA) and heteronuclear experiments (HMQC), including linkage assignments by 1H-13C long-range correlation (HMBC). Complete 1H and 13C NMR assignments for the intact polysaccharide yielded the covalent structure of a heptasaccharide repeating unit: [Formula: see text] The structure of the strain 38 polysaccharide is closely related to those of Streptococcus mitis J22 and Streptococcus oralis 34. Thus, the difference between the strain 38 and J22 heptasaccharides was at their reducing ends, with GaLNAc beta-(1-->3)-Gal in the former and Gal beta-(1-->3)-GalNAc in the latter, while the difference between the 38 heptasaccharide and 34 hexasaccharide was at the non-reducing ends, where a rhamnose branch occurred in the former but not the latter structure. When compared by their quantitative precipitin curves with rabbit antibodies against each streptococcal strain, the strain 38 polysaccharide reacted more like the polysaccharide of strain J22 than that of strain 34. In contrast, each strain was recognized by the Gal- and GalNAc-reactive lectins of Actinomyces spp., but only strains 38 and 34 were recognized by GalNAc-sensitive lectins of other streptococci. These findings strongly support the hypothesis that the immunogenic features of these polysaccharides are distinct from those detected by lectin binding.

Capsular polysaccharide structure of a clinical isolate of Vibrio vulnificus strain BO62316 determined by heteronuclear NMR spectroscopy and high-performance anion-exchange chromatography

Virulence of Vibrio vulnificus has been strongly associated with encapsulation. Capsular polysaccharide was purified from a virulent strain of Vibrio vulnificus BO62316, a clinical isolate, by dialysis, centrifugation, enzymatic digestion, and phenol-chloroform extraction. This polysaccharide shows partial reactivity with antibodies to the capsular polysaccharide of a related pathogenic strain of V. vulnificus (MO6-24) whose structure was recently reported. Nuclear magnetic resonance spectroscopic analysis of the purified polysaccharide from strain BO62316 showed that the polymer is composed of a repeating structure with four sugar residues per subunit: a residue of 2-acetamido-2,6-dideoxy-hexo pyranose in the alpha-gluco configuration (QuiNAc), a residue of 2-acetamido-2,6-dideoxy hexopyranose in the alpha-galacto configuration (FucNAc), a residue of 2-acetamido-2,6-dideoxy hexopyranose in the alpha-manno configuration (RhaNAc), and a residue of 2-acetamido-2,6-dideoxy hexouronate in the alpha-galacto configuration (GalNAcA). The complete carbohydrate structure of the capsular polysaccharide was determined by heteronuclear nuclear magnetic resonance spectroscopy and by high-performance anion-exchange chromatography. The 1H and 13C spectra were completely assigned, and vicinal coupling relationships were used to establish the stereochemistry of each sugar residue, its anomeric configuration, and the position of the glycosidic linkages. The complete structure is Formular; [see text]. This is the first reported occurrence of RhaNAc in a capsular polysaccharide.

Relative role of genes and environment on BP: twin studies in Madras, India

This study was conducted to test the feasibility of the twin research model in a developing country with diverse cultures and to understand the relative influence of genetic and environmental factors on BP variation among South Indians. This was a cross-sectional twin study of volunteers using a two-by-two factorial design for the analysis of quantitative traits. The factors were twin type (monozygotic and dizygotic) and sex (male and female). The study was conducted in Madras. Twenty-four pairs of twins were contacted for participation in the project. Of the 24 pairs we contacted, 91% (20) actually participated in our study. Among 20 sets we studied, 10 (50%) are males and 10 (50%) are females with an average age of 23 years. The mean SBP of this volunteer twin population was 115.18 +/- 1.27 mmHg and DBP was 68.53 +/- 1.41 mmHg. Analysis of dietary habits (vegetarian/nonvegetarian) showed that BP was greater (118.26 +/- 2.29/71.88 +/- 2.34 mmHg) in vegetarian twins than nonvegetarians (112.28 +/- 1.42/66.2 +/- 1.90 mmHg). Also a positive correlation between urinary excretion of calcium and BP was observed. The present study demonstrates that epidemiological research in a developing country like India is feasible and economical, using the twin research methodology. As observed in other populations, the major source of BP variation in the population appears to be predominantly under genetic control.

Capsular types of Vibrio vulnificus: an analysis of strains from clinical and environmental sources

Vibrio vulnificus produces a capsular polysaccharide (CPS) that is essential for virulence. CPS from V. vulnificus clinical strain MO6-24 has been purified and the structure determined. In preliminary screening with antisera raised to MO6-24 CPS, 4 (19%) of 21 clinical isolates (including MO6-24), but none of 67 environmental V. vulnificus isolates, agglutinated with anti-MO6-24 antisera (P = .003). CPS was isolated from a subset of 12 clinical and 7 environmental isolates and analyzed by high-performance anion-exchange chromatography and one-dimensional nuclear magnetic resonance. MO6-24 and 1 other serologically positive strain had identical CPS structures; the other 2 serologically positive strains had substitutions in two of four sugar residues. Thirteen other capsular types were identified among the remaining 15 strains from which CPS was extracted.

Arachidonic acid metabolites as intratesticular factors controlling androgen production

The effect of inhibitors and products of arachidonic acid metabolism on rat testicular steroidogenesis has been investigated. In the presence of indomethacin (inhibitor of cyclooxygenase) and nordihydroguaiaretic acid (NDGA) (inhibitor of lipoxygenase), the activity of 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) and 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) were both inhibited. The LH-stimulated increase in secretion of testosterone and progesterone was also inhibited by indomethacin and NDGA. On the other hand, vitamin E (antioxidant and inhibitor of lipoxygenase), stimulated the activity of both 3 beta-HSD and 17 beta-HSD and enhanced LH-stimulated androgen production. The metabolites of lipoxygenase (15-HPETE, 15-HETE, 5-HPETE and 5-HETE) and cyclooxygenase (PGF2 alpha) pathways stimulated 3 beta-HSD and 17 beta-HSD activity and enhanced the secretion of progesterone and testosterone. It is concluded that arachidonic acid metabolites are intratesticular factors which can regulate LH-stimulated testicular steroidogenesis.

Determination by heteronuclear NMR spectroscopy of the complete structure of the cell wall polysaccharide of Streptococcus sanguis strain K103

Although complete structures of complex polysaccharides have traditionally been determined by chemical degradative methods, a number of recent developments in instrumentation have greatly facilitated this task. We illustrate the application of several of these methods in a determination of the complete covalent structure of the polysaccharide from Streptococcus sanguis K103, which is composed of an octasaccharide repeating subunit linked by phosphodiester bonds. Carbohydrate analysis by HPAE-PAD and by reverse-phase chromatography of benzoylated derivatives of the hydrolysis products of the polysaccharide gave glucose (3 mol), galactose (1 mol), rhamnose (2 mol), N-acetylglucosamine (1 mol), and galactose 6-phosphate (1 mol). Circular dichroism of the O-benzoylated monosaccharides showed the absolute configurations to be D for all residues except for rhamnose, which is L. The 1H NMR spectrum was completely assigned by two-dimensional homonuclear methods (DQF-COSY, NOESY, HOHAHA). The stereochemistry of pyranosides was assigned from 3JHH coupling constant values determined from these experiments. The 13C spectrum was assigned by 1H-detected heteronuclear multiple-quantum correlation (1H[13C] HMQC) and by the hybrid method of HMQC-COSY. The glycosidic linkage positions of the polymer were determined by 1H-detected multiple-bond correlation (1H[13C] HMBC) and by 2D-NOESY spectra. The position of the phosphodiester linkage was determined by splitting observed in the 13C resonances due to 31P couplings leading to the overall structure given in Chart I.

The production of arachidonic acid metabolites in rat testis

There is growing evidence that arachidonic acid is oxygenated enzymatically in every cell type and that the oxygenated metabolites regulate a variety of pathological and physiological processes including reproduction. In the present study, the metabolism of arachidonic acid in the testis via cyclooxygenase and lipoxygenase pathways was analyzed. Testicular microsomes showed substantial cyclooxygenase activity as measured by the polarographic method. Analysis of the products on TLC revealed PGF2 alpha (79.5%) as the main product followed by PGE2 (20.3%) and PGD2 (0.17%). At higher substrate concentrations (150 microM), however, 6-keto-PGF1 alpha, the stable metabolite of prostacyclin, was observed in substantial quantities. Maximum activity of lipoxygenase was observed at pH 6.4 in both microsomes and cytosol, the activity being higher in cytosol. Analysis of lipoxygenase pathway products with arachidonic acid as the substrate, revealed the presence of 12-HPETE as the major product both in cytosol and in microsomes. Besides this, 15- and 5-HPETEs were also observed in substantial quantities.

Calmodulin-specific monoclonal antibodies inhibit DNA replication in mammalian cells

The involvement of calmodulin in the proliferation of Chinese hamster embryo fibroblast cells has been studied with a specific monoclonal antibody to calmodulin. We observed that calmodulin levels increase 2-fold in the late G1 period in these cells, and this coincides with the increase in DNA polymerase alpha activity as the cells progress synchronously from a quiescent state in the G1 to the S phase. However, there is a concurrent 10-fold enhancement of thymidine kinase activity, which is tightly coupled to the entry of cells into the S phase. Incubation of permeabilized S-phase cells with calmodulin-specific murine monoclonal antibody resulted in a dose-dependent inhibition of DNA replication. This inhibitory effect of anti-calmodulin antibodies on DNA replication is completely reversed by the addition of exogenously purified calmodulin. These observations provide evidence for the involvement of calmodulin in DNA replication and, therefore, in cell proliferation during the S phase.

Growth factor-dependent proliferative stimulation of hematopoietic cells is associated with the modulation of cytoplasmic and nuclear 68-Kd calmodulin-binding protein

Calcium and calmodulin (CaM) are known to play critical roles in controlling cell cycle progression in a variety of cells. We observed that the CaM antagonist, N-(6-aminohexyl)-5-chloro-1-naphthalensulfonamide hydrochloride (W-7), inhibited 3H-thymidine incorporation into DNA of factor-dependent hematopoietic cells. To delineate the role of CaM in proliferation of hematopoietic cells, we have investigated intracellular distribution of specific CaM-binding proteins (CaM-BPs) in response to hematopoietic growth factors in FDC-P1, 32D, NFS-60, and T1165 cells. Each of these cell lines, when deprived of cytokines for 16 to 18 hours, essentially ceased proliferation, even in the presence of fetal calf serum. Concomitant to the cessation of proliferation, there was a dramatic depletion of a specific CaM-BP of about 68 Kd in both their cytoplasmic and nuclear fractions. Within 6 to 12 hours of reexposure to proliferation-specific cytokines, there was a restoration of the nuclear as well as cytoplasmic 68-Kd CaM-BP. Furthermore, such an induction and nuclear localization of the 68-Kd CaM-BP by the cytokines coincided temporally with the progression of synchronized FDC-P1 cells from G1 to S phase. By contrast, colony-stimulating factor-1 (CSF-1)-dependent bone marrow macrophages and BAC-1 cells did not exhibit 68-Kd CaM-BP in the nuclear or cytoplasmic fractions. These studies suggest that while hematopoietic growth factor granulocyte CSF-, granulocyte-macrophage CSF-, interleukin-3 (IL-3)-, or IL-6-, whose receptors are members of the hematopoietin receptor family, induced cell proliferation is associated with a common mechanism involving nuclear localization of the 68-Kd CaM-BP, the CSF-1-induced proliferation seems to involve 68-Kd CaM-BP-independent pathways.

Purification and determination of the structure of capsular polysaccharide of Vibrio vulnificus M06-24

Virulence of Vibrio vulnificus has been strongly associated with encapsulation and an opaque colony morphology. Capsular polysaccharide was purified from a whole-cell, phosphate-buffered saline-extracted preparation of the opaque, virulent phase of V. vulnificus M06-24 (M06-24/O) by dialysis, centrifugation, enzymatic digestion, and phenol-chloroform extraction. Nuclear magnetic resonance spectroscopic analysis of the purified polysaccharide showed that the polymer was composed of a repeating structure with four sugar residues per repeating subunit: three residues of 2-acetamido-2,6-dideoxyhexopyranose in the alpha-gluco configuration (QuiNAc) and an additional residue of 2-acetamido hexouronate in the alpha-galactopyranose configuration (GalNAcA). The complete carbohydrate structure of the polysaccharide was determined by heteronuclear nuclear magnetic resonance spectroscopy and by high-performance anion-exchange chromatography. The 1H and 13C nuclear magnetic resonance spectra were completely assigned, and vicinal coupling relationships were used to establish the stereochemistry of each sugar residue, its anomeric configuration, and the positions of the glycosidic linkages. The complete structure is: [----3) QuipNAc alpha-(1----3)-GalpNAcA alpha-(1----3)-QuipNAc alpha-(1----]n QuipNAc alpha-(1----4)-increases The polysaccharide was produced by a translucent phase variant of M06-24 (M06-24/T) but not by a translucent, acapsular transposon mutant (CVD752). Antibodies to the polysaccharide were demonstrable in serum from rabbits inoculated with M06-24/O.