Microbial Indicators of Dental Health, Dysbiosis, and Early Childhood Caries.

Dental caries lesions are a clinical manifestation of disease, preceded by microbial dysbiosis, which is poorly characterized and thought to be associated with saccharolytic taxa. Here, we assessed the associations between the oral microbiome of children and various caries risk factors such as demographics and behavioral and clinical data across early childhood and characterized over time the salivary and dental plaque microbiome of children before clinical diagnosis of caries lesions. Children (N = 266) were examined clinically at ~1, 2.5, 4, and 6.5 y of age. The microbiome samples were collected at 1, 2.5, and 4 y. Caries groups consisted of children who remained caries free (International Caries Detection and Assessment System [ICDAS] = 0) at all time points (CFAT) (n = 50); children diagnosed with caries (ICDAS ≥ 1) at 6.5 y (C6.5), 4 y (C4), or 2.5 y of age (C2.5); and children with early caries or advanced caries lesions at specific time points. Microbial community analyses were performed on zero-radius operational taxonomic units (zOTUs) obtained from V4 of 16S ribosomal RNA gene amplicon sequences. The oral microbiome of the children was affected by various factors, including antibiotic use, demographics, and dietary habits of the children and their caregivers. At all time points, various risk factors explained more of the variation in the dental plaque microbiome than in saliva. At 1 y, composition of saliva of the C4 group differed from that of the CFAT group, while at 2.5 y, this difference was observed only in plaque. At 4 y, multiple salivary and plaque zOTUs of genera Prevotella and Leptotrichia were significantly higher in samples of the C6.5 group than those of the CFAT group. In conclusion, up to 3 y prior to clinical caries detection, the oral microbial communities were already in a state of dysbiosis that was dominated by proteolytic taxa. Plaque discriminated dysbiotic oral ecosystems from healthy ones better than saliva.

Stress modulation as a means to improve yeasts for lignocellulose bioconversion.

The second-generation (2G) fermentation environment for lignocellulose conversion presents unique challenges to the fermentative organism that do not necessarily exist in other industrial fermentations. While extreme osmotic, heat, and nutrient starvation stresses are observed in sugar- and starch-based fermentation environments, additional pre-treatment-derived inhibitor stress, potentially exacerbated by stresses such as pH and product tolerance, exist in the 2G environment. Furthermore, in a consolidated bioprocessing (CBP) context, the organism is also challenged to secrete enzymes that may themselves lead to unfolded protein response and other stresses. This review will discuss responses of the yeast Saccharomyces cerevisiae to 2G-specific stresses and stress modulation strategies that can be followed to improve yeasts for this application. We also explore published -omics data and discuss relevant rational engineering, reverse engineering, and adaptation strategies, with the view of identifying genes or alleles that will make positive contributions to the overall robustness of 2G industrial strains. KEYPOINTS: • Stress tolerance is a key driver to successful application of yeast strains in biorefineries. • A wealth of data regarding stress responses has been gained through omics studies. • Integration of this knowledge could inform engineering of fit for purpose strains.

Subgingival Microbiota during Healthy Pregnancy and Pregnancy Gingivitis.

INTRODUCTION: Previous studies have largely explored the microbial composition and pathogenesis of pregnancy gingivitis. However, the patterns of microbial colonization during pregnancy in the absence of pregnancy gingivitis have rarely been studied. Characterization of the oral microbiome in pregnant women with healthy gingiva is an important initial step in understanding the role of the microbiome in progression to pregnancy gingivitis. OBJECTIVES: In this study, we compared the oral microbiome of pregnant women without gingivitis (healthy pregnancy) with pregnant women having gingivitis and nonpregnant healthy women to understand how pregnancy modifies the oral microbiome and induces progression to pregnancy gingivitis. METHODS: Subgingival plaque samples were collected from Chinese pregnant women with gingivitis (n = 10), healthy pregnant women (n = 10), and nonpregnant healthy women (n = 10). The Illumina MiSeq platform was used to perform 16S rRNA gene sequencing targeting the V4 region. RESULTS: The alpha and beta diversity was significantly different between pregnant and nonpregnant women, but minimal differences were observed between pregnant women with and without gingivitis. Interestingly, the oral bacterial community showed higher abundance of pathogenic taxa during healthy pregnancy as compared with nonpregnant women despite similar gingival and plaque index scores. However, when compared with overt pregnancy gingivitis, pathogenic taxa were less abundant during healthy pregnancy. PICRUSt analysis (phylogenetic investigation of communities by reconstruction of unobserved states) also suggested no difference in the functional capabilities of the microbiome during pregnancy, irrespective of gingival disease status. However, metabolic pathways related to amino acid metabolism were significantly increased in healthy pregnant women as compared with nonpregnant women. CONCLUSION: The presence of pathogenic taxa in healthy pregnancy and pregnancy gingivitis suggests that bacteria may be necessary for initiating disease development but progression to gingivitis may be influenced by the host environmental factors. More efforts are required to plan interventions aimed at sustaining health before the appearance of overt gingivitis. KNOWLEDGE TRANSFER STATEMENT: The results of this study draw attention to the importance of oral health maintenance during pregnancy, as women without any prenatal oral conditions are predisposed to the risk of developing pregnancy gingivitis. Hence, it is important to incorporate comprehensive assessment of oral health in the prenatal health care schedules. Pregnant woman should be screened for oral risks, counseled on proper oral hygiene and expected oral changes, and referred for dental treatment, when necessary.

Home sampling is a feasible method for oral microbiota analysis for infants and mothers.

OBJECTIVES: Large longitudinal cohort studies in infants are needed to understand oral microbiome maturation in relation to general health. The logistics of such studies are complex and costs involved high. Methods like home sampling by caretakers might be a solution to these issues. This study aimed to evaluate feasibility of home sampling by caretakers and to assess which oral niche provides the most reliable sample. METHODS: In this cross-sectional study 30 mothers and their infants aged 2-15 months participated. Swabs of the tongue, buccal mucosa, saliva, and dental plaque of the mother and the infant were collected by the mother after watching an instruction video. Thereafter, the trained researcher repeated the sample collection. Variations on the sampling protocol were listed. Bacterial DNA was quantified and microbial composition was assessed using 16S rDNA amplicon sequencing. RESULTS: None of the sampled niches appeared to be unfeasible based on interviews and observed variations on protocol. No significant differences in bacterial DNA concentration between operators (mother and researcher) were found. In infant's saliva, Shannon diversity of samples collected by the researcher was significantly higher than those collected by mothers (p = 0.0009) and the bacterial composition was influenced by variations on sampling protocol (p = 0.01). CONCLUSIONS: Home sampling by caretakers is a feasible method for oral sample collection in infants and mothers. Oral samples collected by mothers resemble samples collected by a trained researcher, with the tongue sample being the most similar and saliva the least. CLINICAL SIGNIFICANCE: Home sampling can simplify longitudinal oral microbiota collection.

Dental aerosols: microbial composition and spatial distribution.

Background: High-speed dental instruments produce aerosols, which can contribute to the transmission of pathogenic microorganisms. The aim of this study is to describe the microbial load and - composition and spatial distribution of aerosols in dental clinics. Methods: In four dental clinics active and passive sampling methods were used before, during and after treatment and at different locations. Retrieved colony forming units (CFU) were sequenced for taxon identification. Results: The samples contained up to 655 CFU/plate/30 minutes and 418 CFU/m3/30 minutes during dental treatment for active and passive sampling, respectively. The level of contamination after treatment and at 1.5 m distance from the patient's head was similar to the start of the day. The highest contamination was found at the patient's chest area. The aerosols consisted of 52 different taxa from human origin and 36 from water. Conclusion: Contamination in dental clinics due to aerosols is mainly low, although high level of contamination with taxa from both human and water origin was found within 80 cm around the head of the patient. Our results stress the importance of infection control measures on surfaces in close proximity to the head of the patient as well as in dental water lines.

Impact of the early-life skin microbiota on the development of canine atopic dermatitis in a high-risk breed birth cohort.

Canine atopic dermatitis (CAD) is a prevalent inflammatory skin disease of dogs worldwide. Certain breeds such as the West Highland White Terriers (WHWT) are predisposed to suffer from CAD. Microbial dysbiosis is known to play a significant role in the pathogenesis of the disease, which is similar to its human counterpart, atopic dermatitis (AD). To date, no large cohort-study has been conducted in a predisposed dog breed to study the impact of the early-life microbiota on the development of CAD, as well as the possible implication of factors such as hygiene and access to the outdoors. In this study skin samples of 143 WHWT, including 109 puppies up to three weeks old and 34 parent dogs, from 17 breeders, were subjected to 16S rRNA gene and ITS2 amplicon sequencing to disclose the bacterial and fungal oral and skin microbiota, respectively. The oral samples served as a control group to confirm differences between haired and mucosal surfaces. The cutaneous microbiota differed between sample sites and age of the dogs. The season of sampling, geographical origin as well as hygiene status of the household and the access to the outdoors shaped the skin microbiota of the puppies significantly. However, we found that the individual early-life microbiota did not predispose for the later development of CAD.

Maturation of the Oral Microbiome in Caries-Free Toddlers: A Longitudinal Study.

Understanding the development of the oral microbiota in healthy children is of great importance to oral and general health. However, limited data exist on a healthy maturation of the oral microbial ecosystem in children. Moreover, the data are biased by mislabeling "caries-free" populations. Therefore, we aimed to characterize the healthy salivary and dental plaque microbiome in young children. Caries-free (ICDAS [International Caries Detection and Assessment System] score 0) children (n = 119) and their primary caregivers were followed from 1 until 4 y of child age. Salivary and dental plaque samples were collected from the children at 3 time points (T1, ~1 y old; T2, ~2.5 y old; and T3, ~4 y old). Only saliva samples were collected from the caregivers. Bacterial V4 16S ribosomal DNA amplicons were sequenced using Illumina MiSeq. The reads were denoised and mapped to the zero-radius operational taxonomic units (zOTUs). Taxonomy was assigned using HOMD. The microbial profiles of children showed significant differences (P = 0.0001) over time. Various taxa increased, including Fusobacterium, Actinomyces, and Corynebacterium, while others showed significant decreases (e.g., Alloprevotella and Capnocytophaga) in their relative abundances over time. Microbial diversity and child-caregiver similarity increased most between 1 and 2.5 y of age while still not reaching the complexity of the caregivers at 4 y of age. The microbiome at 1 y of age differed the most from those at later time points. A single zOTU (Streptococcus) was present in all samples (n = 925) of the study. A large variation in the proportion of shared zOTUs was observed within an individual child over time (2% to 42% of zOTUs in saliva; 2.5% to 38% in dental plaque). These findings indicate that the oral ecosystem of caries-free toddlers is highly heterogeneous and dynamic with substantial changes in microbial composition over time and only few taxa persisting across the 3 y of the study. The salivary microbiome of 4-y-old children is still distinct from that of their caregivers.

Long-term impact of oral surgery with or without amoxicillin on the oral microbiome-A prospective cohort study.

Routine postoperative antibiotic prophylaxis is not recommended for third molar extractions. However, amoxicillin still continues to be used customarily in several clinical practices worldwide to prevent infections. A prospective cohort study was conducted in cohorts who underwent third molar extractions with (group EA, n = 20) or without (group E, n = 20) amoxicillin (250 mg three times daily for 5 days). Further, a control group without amoxicillin and extractions (group C, n = 17) was included. Salivary samples were collected at baseline, 1-, 2-, 3-, 4-weeks and 3 months to assess the bacterial shift and antibiotic resistance gene changes employing 16S rRNA gene sequencing (Illumina-Miseq) and quantitative polymerase chain reaction. A further 6-month follow-up was performed for groups E and EA. Seven operational taxonomic units reported a significant change from baseline to 3 months for group EA (adjusted p < 0.05). No significant change in relative abundance of bacteria and ß-lactamase resistance genes (TEM-1) was observed over 6 months for any group (adjusted p > 0.05). In conclusion, the salivary microbiome is resilient to an antibiotic challenge by a low-dose regimen of amoxicillin. Further studies evaluating the effect of routinely used higher dose regimens of amoxicillin on gram-negative bacteria and antibiotic resistance genes are warranted.

Weak Decay of Magnetized Pions.

The leptonic decay of charged pions is investigated in the presence of background magnetic fields. In this situation, Lorentz symmetry is broken, and new fundamental decay constants need to be introduced, associated with the decay via the vector part of the electroweak current. We calculate the magnetic field dependence of both the usual and a new decay constant nonperturbatively on the lattice. We employ both Wilson and staggered quarks and extrapolate the results to the continuum limit. With this nonperturbative input, we calculate the tree level electroweak amplitude for the full decay rate in strong magnetic fields. We find that the muonic decay of the charged pion is enhanced drastically by the magnetic field. We comment on possible astrophysical implications.

Small dense LDL cholesterol in human subjects with different chronic inflammatory diseases.

BACKGROUND AND AIMS: Chronic inflammatory diseases (CID) are associated with a profound increase in cardiovascular (CV) risk resulting in reduced life expectancy. However, LDL-cholesterol is reported to be low in CID patients which is referred to as the "LDL paradoxon". The aim of the present study was to investigate whether LDL-particles in CID exhibit an increased content of the highly atherogenic small-dense LDL subfraction (sdLDL). METHODS AND RESULTS: In this prospective, single center, observational study we enrolled 141 patients with CID (RA n = 59, inflammatory bowel disease (IBD) n = 35, ankylosing spondylitis (SpA) n = 25, Psoriasis n = 22) in 2011 through 2013 to evaluate sdLDL levels before as well as 6 and 26 weeks after initiation of different anti-cytokine therapies (anti-TNFα, anti-IL-6R antibodies). sdLDL levels were compared to 141 healthy individuals in a case control design. Compared to healthy controls, all CID patients displayed a significantly higher sdLDL content within the LDL cholesterol fraction: RA 35.0 ± 9.2% (p < 0.001), SpA 42.5 ± 10.5% (p < 0.001), IBD 37.5 ± 7.1% (p < 0.001), Psoriasis 33.6 ± 4.6% (p < 0.01). Furthermore, the sdLDL/LDL ratio was significantly higher in male compared to female RA subjects (p < 0.05). Neither anti-TNFα nor anti-IL6R medication altered sdLDL levels despite a significant improvement of disease activity. CONCLUSION: In several different chronic inflammatory disease entities, LDL-cholesterol is shifted toward a pro-atherogenic phenotype due to an increased sdLDL content which might in part explain the LDL paradoxon. Since premature CV disease is a major burden of affected patients, specifically targeting lipid metabolism should be considered routinely in clinical patient care. CLINICAL TRIALS: Registration at German Clinical Trial Register (DRKS): DRKS00005285.

Disparity in fetal growth between twin and singleton gestation: the role of adipokines.

OBJECTIVE: Twin pregnancies are characterized by unique pattern of attenuated fetal weight gain during late gestation compared with singleton gestation. The mechanism(s) responsible for regulating twin growth has not yet elucidated. Leptin and adiponectin are two adipocytokines implicated in metabolism and energy balance of fetuses, newborns and adults. Moreover, these hormones have been suggested to play a role in fetal growth. The objective of the study was to determine cord blood adiponectin and leptin in twins and singletons, with and without growth impairment. STUDY DESIGN: This was a case-control study. It included two groups of newborns, matched for gestational age and birth weight percentile: singleton (n=60 newborns) and twins (n=44 newborns). Adiponectin and leptin were determined in cord blood, and compared between the groups according to clinical and demographic characteristics. Non-parametric and parametric statistical methods were employed. RESULTS: Median adiponectin and leptin concentrations were lower in twins vs singletons (P<0.001 for both comparisons). Among small for gestational age newborns (SGA), median concentration of adiponectin (P=0.04), but not leptin (P=0.1), was lower in twins compared to singletons. In pooled analysis (singleton plus twins), cord blood adiponectin and leptin were strongly correlated with gestational age (P<0.001 and P=0.005, respectively) and birth weight (P<0.001 and P<0.001, respectively). Regression analysis revealed that plurality (P=0.02) was significantly and independently associated with cord blood adiponectin concentrations, after adjustment for confounding variables. Similar regression in which leptin was the independent variable revealed that only birth weight (P=0.01) was significantly and independently associated with cord blood leptin concentrations. CONCLUSIONS: Twin pregnancies are associated with lower cord blood concentrations of adiponectin and leptin compared with singleton gestations. However, only cord blood adiponectin, but not leptin, was lower in SGA neonates. Collectively, these data suggest that adiponectin may be implicated in the mechanism accounting for the growth disparity between twins and singletons.

Continuous versus batch production of lipids in the microalgae Acutodesmus obliquus.

This work provides a novel quantitative comparison of batch versus continuous microalgal lipid production in the wild type and starchless mutant strain of Acutodesmus obliquus. Both strains showed higher TAG yields on light under batch operation compared to continuous nitrogen limitation. The starchless mutant showed 0.20gTAGmolph-1 for batch and 0.12gTAGmolph-1 for continuous operation, while the wildtype only showed 0.16gTAGmolph-1 for batch and 0.08gTAGmolph-1 for continuous operation. Also, higher TAG contents were found under batch starvation (26% of dry weight for the wildtype and 43% of dry weight for starchless mutant) compared to continuous cultivations (16% of dry weight for the wildtype and 33% of dry weight for starchless mutant). Starch acts as the favoured storage metabolite during nitrogen limitation in A. obliquus, whereas TAG is only accumulated after starch reaches a cellular maximum of 40% of dry weight.

Candida albicans alters the bacterial microbiome of early in vitro oral biofilms.

The yeast Candida albicans is an oral commensal microorganism, occurring in the oral cavity of 50-70% of healthy individuals. Its effect on oral ecology has mostly been studied using dual-species models, which disregards the complex nature of oral biofilms. The aim of this study was to culture C. albicans in a complex model to study its effect on oral biofilms. Biofilms, inoculated using pooled stimulated saliva with or without addition of C. albicans, were grown under anaerobic, aerobic, or aerobic +5% CO2 conditions. Red autofluorescence was quantified using a spectrophotometer and visualized in fluorescence photographs. The microbiome of 5 h biofilms was determined using 16S rDNA sequencing. C. albicans was only able to proliferate in biofilms grown under aerobic conditions. After 48 h, C. albicans did not induce differences in total biofilm formation, lactic acid accumulation (cariogenic phenotype) or protease activity (periodontitis phenotype). In vitro, anaerobically grown biofilms developed red autofluorescence, irrespective of inoculum. However, under aerobic conditions, only C. albicans-containing biofilms showed red autofluorescence. Facultative or strict anaerobic Veillonella, Prevotella, Leptotrichia, and Fusobacterium genera were significantly more abundant in biofilms with C. albicans. Biofilms without C. albicans contained more of the aerobic and facultative anaerobic genera Neisseria, Rothia, and Streptococcus. The presence of C. albicans alters the bacterial microbiome in early in vitro oral biofilms, resulting in the presence of strictly anaerobic bacteria under oxygen-rich conditions. This in vitro study illustrates that C. albicans should not be disregarded in healthy oral ecosystems, as it has the potential to influence bacteria significantly.

Microbial profiles at baseline and not the use of antibiotics determine the clinical outcome of the treatment of chronic periodontitis.

Antibiotics are often used in the treatment of chronic periodontitis, which is a major cause of tooth loss. However, evidence in favour of a microbial indication for the prescription of antibiotics is lacking, which may increase the risk of the possible indiscriminate use of antibiotics, and consequent, microbial resistance. Here, using an open-ended technique, we report the changes in the subgingival microbiome up to one year post-treatment of patients treated with basic periodontal therapy with or without antibiotics. Antibiotics resulted in a greater influence on the microbiome 3 months after therapy, but this difference disappeared at 6 months. Greater microbial diversity, specific taxa and certain microbial co-occurrences at baseline and not the use of antibiotics predicted better clinical treatment outcomes. Our results demonstrate the predictive value of specific subgingival bacterial profiles for the decision to prescribe antibiotics in the treatment of periodontitis, but they also indicate the need for alternative therapies based on ecological approaches.

Fetal Brain MRI: Novel Classification and Contribution to Sonography.

PURPOSE: 1) To evaluate and classify the indications for fetal brain MRI in a tertiary referral center. 2) To assess the contribution of fetal brain MRI to fetal neurosonography. MATERIALS AND METHODS: A retrospective study in a tertiary medical center during a two-year period (2011 - 2012) included pregnant women who underwent fetal brain MRI. MRI was implemented at 32 weeks of gestation unless a severe abnormality possibly requiring earlier medical intervention was suspected. RESULTS: 633 patients were included, 40 (6.3%) underwent repeated examinations with a total of 733 fetal MRI scans. Patients were classified to three main indication cohorts: Suspected primary brain anomaly (52.9%), non-CNS disorders (32.5%) and obstetrical complications (14.6%). These cohorts were further divided into 16 separate groups with lateral ventricle abnormalities being the most common (23.7%), followed by exposure to TORCH (17.5%) and cerebral cortex abnormalities (13%). 149 (19.3%) fetal MRI scans demonstrated additional findings. Repeated examinations were commonly implemented in complicated monochorionic-biamniotic (MCBA) twin pregnancies (34.6%) and in cases of supra-tentorial cysts (19%). The average gestational age for MRI scan in the MCBA group was 26 ±â€Š5 weeks in comparison to ≥ 31st weeks in all other groups (p < 0.001). CONCLUSION: The current study describes a detailed picture of fetal brain MRI indications. Most patients were referred because of CNS anomalies. The impressive diversity of 16 separate entities emphasizes the expanding use of fetal brain MRI. Complicated MCBA pregnancies, which may have dramatic events, constitute a unique challenge due to early and repetitive MRI examinations and may serve as a role model for the contribution of fetal MRI during antenatal evaluation. The contribution of MRI to prenatal evaluation in various indications is discussed.

The effect of propidium monoazide treatment on the measured bacterial composition of clinical samples after the use of a mouthwash.

OBJECTIVES: The use of an anti-microbial mouthwash results not only in a reduction of the number of viable cells in dental plaque but potentially also in a shift in the oral microbiome. DNA-based techniques may be appropriate to monitor these shifts, but these techniques amplify DNA from both dead and living cells. Propidium monoazide (PMA) has been used to overcome this problem, by preventing the amplification of DNA from membrane-damaged cells. The aim of this study was to evaluate the use of PMA when measuring compositional shifts in clinical samples after mouthwash use. MATERIALS AND METHODS: On two consecutive days, baseline samples from buccal surfaces, tongue, and saliva were obtained from six volunteers, after which they used a mouthwash (Meridol, GABA, Switzerland) twice daily for 14 days. Subsequently similar samples were obtained on two consecutive days. The microbial composition of the samples, with or without ex vivo PMA treatment, was assessed with 16S rRNA gene amplicon sequencing. RESULTS: Data showed a clear effect of mouthwash usage on the tongue and saliva samples. PMA treatment enhanced the observed differences only for the saliva samples. Mouthwash treatments did not affect the composition of the plaque samples irrespective of the use of PMA. CONCLUSION: The necessity to use a PMA treatment to block the DNA from dead cells in clinical studies aimed at measuring compositional shifts after the use of a mouthwash is limited to salivary samples. CLINICAL RELEVANCE: Measuring shifts in the oral microbiome could be hampered by the presence of DNA from dead cells.

Intra- and postoperative catumaxomab in patients with epithelial ovarian cancer: safety and two-year efficacy results from a multicentre, single-arm, phase II study.

BACKGROUND: This is the first study investigating the safety and efficacy of the trifunctional antibody catumaxomab administered i.p. at the end of cytoreductive surgery and postoperatively prior to standard chemotherapy in patients with primary epithelial ovarian cancer (EOC). METHODS: Patients received i.p. catumaxomab 10 µg intraoperatively and 10, 20, 50 and 150 µg on days 7, 10, 13 and 16, respectively, postoperatively. After the study, patients received standard chemotherapy and were followed for 23 months. The primary endpoint was the rate of postoperative complications. RESULTS: Forty-one patients entered the study and were evaluable for safety and 34 were alive at 24 months. Complete tumour resection rate was 68%. Postoperative complications were observed in 51%, the most common anastomotic leakage (7%) and wound infections (5%). The most common catumaxomab-related adverse events were abdominal pain, nausea, vomiting and pyrexia. Thirty-nine percent discontinued catumaxomab therapy, and 98% received chemotherapy post study. Kaplan-Meier estimates of disease-free and overall survival after 24 months were 56% and 85%, respectively. CONCLUSIONS: Intra- and close postoperative catumaxomab seems feasible, but efficacy and safety were limited by postsurgical complications. In the future prospective trials are needed to investigate the best schedule of integration of catumaxomab into current treatment strategies for EOC.

An apparatus for pulsed ESR and DNP experiments using optically excited triplet states down to liquid helium temperatures.

In standard Dynamic Nuclear Polarization (DNP) electron spins are polarized at low temperatures in a strong magnetic field and this polarization is transferred to the nuclear spins by means of a microwave field. To obtain high nuclear polarizations cryogenic equipment reaching temperatures of 1 K or below and superconducting magnets delivering several Tesla are required. This equipment strongly limits applications in nuclear and particle physics where beams of particles interact with the polarized nuclei, as well as in neutron scattering science. The problem can be solved using short-lived optically excited triplet states delivering the electron spin. The spin is polarized in the optical excitation process and both the cryogenic equipment and magnet can be simplified significantly. A versatile apparatus is described that allows to perform pulsed dynamic nuclear polarization experiments at X-band using short-lived optically excited triplet sates. The efficient (4)He flow cryostat that cools the sample to temperatures between 4 K and 300 K has an optical access with a coupling stage for a fiber transporting the light from a dedicated laser system. It is further designed to be operated on a neutron beam. A combined pulse ESR/DNP spectrometer has been developed to observe and characterize the triplet states and to perform pulse DNP experiments. The ESR probe is based on a dielectric ring resonator of 7 mm inner diameter that can accommodate cubic samples of 5mm length needed for neutron experiments. NMR measurements can be performed during DNP with a coil integrated in the cavity. With the presented apparatus a proton polarization of 0.5 has been achieved at 0.3 T.