Markedly increased risk of postoperative bleeding complications during perioperative bridging anticoagulation in general and visceral surgery.

BACKGROUND: Increasing numbers of patients receiving oral anticoagulants are undergoing elective surgery. Low molecular weight heparin (LMWH) is frequently applied as bridging therapy during perioperative interruption of anticoagulation. The aim of this study was to explore the postoperative bleeding risk of patients receiving surgery under bridging anticoagulation. METHODS: We performed a monocentric retrospective two-arm matched cohort study. Patients that received perioperative bridging anticoagulation were compared to a matched control group with identical surgical procedure, age, and sex. Emergency and vascular operations were excluded. The primary endpoint was the incidence of major postoperative bleeding. Secondary endpoints were minor postoperative bleeding, thromboembolic events, length of stay, and in-hospital mortality. Multivariate analysis explored risk factors of major postoperative bleeding. RESULTS: A total of 263 patients in each study arm were analyzed. The patient cohort included the entire field of general and visceral surgery including a large proportion of major oncological resections. Bridging anticoagulation increased the postoperative incidence of major bleeding events (8% vs. 1%; p < 0.001) as well as minor bleeding events (14% vs. 5%; p < 0.001). Thromboembolic events were equally rare in both groups (1% vs. 2%; p = 0.45). No effect on mortality was observed (1.5% vs. 1.9%). Independent risk factors of major postoperative bleeding were full-therapeutic dose of LMWH, renal insufficiency, and the procedure-specific bleeding risk. CONCLUSION: Perioperative bridging anticoagulation, especially full-therapeutic dose LMWH, markedly increases the risk of postoperative bleeding complications in general and visceral surgery. Surgeons should carefully consider the practice of routine bridging.

[Distal Forearm Fractures in Children and Adolescents: Frequency and Health Care Provision in Germany]. / Distale Unterarmfrakturen im Kindes- und Jugendalter: Häufigkeit und Versorgungsgeschehen in Deutschland.

BACKGROUND: Despite their frequent occurrence, there are no standardized recommendations for treating distal forearm fractures in growing children. Due to the marked remodelling capacity, conservative therapy is the first choice treatment of fractures in children. However, there are concerns that the possibilities of conservative treatments are often underestimated. Information on the health care situation in Germany on this issue is scarce. METHODS: The present study is based on routine data of a German Health Insurance fund, the Gmünder ErsatzKasse (GEK). Data on diagnoses and treatment of insured persons aged 0-15 years were analysed for the period from 01/07/2005 to 30/06/2009 regarding the frequency of distal forearm fractures and fracture treatment. RESULTS: The overall incidence rate was 56.8 per 10 000 person-years (64.5 in boys; 48.7 in girls). Most of the distal forearm fractures occurred during spring and summer months. The majority of the fractures were immobilized in a plaster cast (84.2%; n=2 609). 8.7% (n=270) of the fractures were treated with closed reduction and percutaneous osteosynthesis. 4.5% (n=138) were treated with closed reduction without any form of osteosynthesis. Only 1.4% (n=43) of the fractures were treated with open reduction. CONCLUSION: Our study shows that boys suffer distal forearm fractures more frequently than girls and that incidences tend to be higher in older children. In addition, analyses indicated seasonal differences between the age groups. In childhood, distal forearm fractures were treated more often conservatively than operatively. However, it was remarkable that fractures in the case of closed reduction were more frequently fixed with an osteosynthesis than just by immobilization in a plaster cast.

Illness perception is significantly determined by depression and anxiety in systemic lupus erythematosus.

Objectives Illness perception is a cognitive representation influencing physical and psychological functioning and adherence in patients with rheumatic disease. Studies exploring illness perception in systemic lupus erythematosus (SLE) are still scarce and none of them have investigated factors determining illness perception. We aimed to assess illness perception and to identify psychological, clinical and sociodemographic factors that might influence illness perception in SLE. Methods The study involved 80 patients with SLE (87.5% women, mean age 41.56 years). The Brief Illness Perception Questionnaire, State Trait Anxiety Inventory, Beck Depression Inventory, Pittsburgh Sleep Quality Index, Visual Analogue Scale-Pain and Fatigue Severity Scale were used. Clinical and sociodemographic data were collected via structured interview and medical files review. Results Illness perception was significantly positively correlated with anxiety, depression, sleep quality, fatigue and pain while it was not related to age, education, steroid treatment, disease duration and activity (SLEDAI) or organ damage (SLICC/ACR). Regression analysis revealed that state anxiety and depression explained 43% of illness perception variance. Cluster analysis identified three patient groups among which the middle-aged group had the most negative illness perception, the highest levels of anxiety, depression, pain and fatigue, and the poorest sleep quality. Conclusions The study has proved a significant relationship between negative illness perception and anxiety and depression. Patients reporting fatigue, poor sleep and pain might have special needs in terms of psychological intervention focused on negative illness perception and distress symptoms. Multidisciplinary care in managing SLE seems to be of great importance.

Prevalence and correlates of suicidal thoughts in patients with neuropsychiatric lupus.

BACKGROUND: Suicidal ideation is observed in patients with systemic lupus erythematosus (SLE). No study on this notable phenomenon in neuropsychiatric SLE (NPSLE) is available so far. METHODS: Participants were 53 consecutive outpatients with NPSLE (48 women; mean age 43.8 years) diagnosed according to the American College of Rheumatology nomenclature for SLE neuropsychiatric syndromes. A Neuropsychiatric Questionnaire (NP-Q) concerning 45 neurological, cognitive and psychiatric symptoms was used to assess the prevalence of self-perceived neuropsychiatric symptoms. The Modified Hospital Anxiety and Depression Scale (HADS-M) was used to assess the level of anxiety, depression and irritability. Formal neuropsychological examination was performed. Clinical data were collected by means of medical charts review and structured interview. RESULTS: Suicidal thoughts were present in 25% of patients with NPSLE, irrespective of sex, age, education, work status, disease duration and steroid treatment. Suicidal ideation was connected with elevated levels of depression, anxiety and irritability. In patients with suicidal ideation the prevalence of cognitive, psychiatric and neurological self-perceived problems was significantly higher. CONCLUSIONS: Suicidal thoughts are common in patients with NPSLE. Neuropsychiatric manifestation per se, depression, anxiety and patients' subjective complaints can be risk factors for suicidal ideation. Screening for suicidal thoughts is vital in routine care of SLE patients.

Differential effects of P2Y1 deletion on glial activation and survival of photoreceptors and amacrine cells in the ischemic mouse retina.

Gliosis of retinal Müller glial cells may have both beneficial and detrimental effects on neurons. To investigate the role of purinergic signaling in ischemia-induced reactive gliosis, transient retinal ischemia was evoked by elevation of the intraocular pressure in wild-type (Wt) mice and in mice deficient in the glia-specific nucleotide receptor P2Y1 (P2Y1 receptor-deficient (P2Y1R-KO)). While control retinae of P2Y1R-KO mice displayed reduced cell numbers in the ganglion cell and inner nuclear layers, ischemia induced apoptotic death of cells in all retinal layers in both, Wt and P2Y1R-KO mice, but the damage especially on photoreceptors was more pronounced in retinae of P2Y1R-KO mice. In contrast, gene expression profiling and histological data suggest an increased survival of amacrine cells in the postischemic retina of P2Y1R-KO mice. Interestingly, measuring the ischemia-induced downregulation of inwardly rectifying potassium channel (Kir)-mediated K(+) currents as an indicator, reactive Müller cell gliosis was found to be weaker in P2Y1R-KO (current amplitude decreased by 18%) than in Wt mice (decrease by 68%). The inner retina harbors those neurons generating action potentials, which strongly rely on an intact ion homeostasis. This may explain why especially these cells appear to benefit from the preserved Kir4.1 expression in Müller cells, which should allow them to keep up their function in the context of spatial buffering of potassium. Especially under ischemic conditions, maintenance of this Müller cell function may dampen cytotoxic neuronal hyperexcitation and subsequent neuronal cell loss. In sum, we found that purinergic signaling modulates the gliotic activation pattern of Müller glia and lack of P2Y1 has janus-faced effects. In the end, the differential effects of a disrupted P2Y1 signaling onto neuronal survival in the ischemic retina call the putative therapeutical use of P2Y1-antagonists into question.

Heteronuclear dipolar coupling in spin-1 NQR pulsed spin locking.

We investigate theoretically and experimentally the role of broadening due to heteronuclear dipolar coupling in spin-1 nuclear quadrupole resonance pulsed spin locking. We find the experimental conditions where heteronuclear dipolar coupling is refocused by a standard multipulse sequence. This experimental condition allows us to extend our previously reported ability to measure the homonuclear dipolar coupling of powder samples to include substances that have heteronuclear coupling. These results are useful for designing substance detection algorithms, and for performing sample characterization.

Indication for allogeneic stem cell transplantation in Glanzmann's thrombasthenia.

Glanzmann's thrombasthenia (GT) is an autosomal recessive disorder characterized by a lack of thrombocyte aggregation due to the absence of thrombocyte glycoproteins IIb and αIIbß3. The role of haematopoietic stem cell transplantation (HSCT) in GT remains controversial. However, HSCT offers the only curative approach for patients with a severe clinical phenotype. In this review, we will discuss the limitation of current status evidence and the specific risk of GT, in particular the alloimmunization and refractoriness to thrombocyte infusions. 19 successful HSCT in 18 GT type I patients have been reported. Mean age at transplantation was 5 years. All patients are still alive. The majority received sibling bone marrow transplant with busulfan and cyclophosphamid conditioning. GvHD incidence was within the normal range, but 10 patients showed alloimmunization of thrombocytes. Median follow up is 25 months.

Rabi and Larmor nuclear quadrupole double resonance of spin-1 nuclei.

We demonstrate the creation of two novel double-resonance conditions between spin-1 and spin-1/2 nuclei in a crystalline solid. Using a magnetic field oscillating at the spin-1/2 Larmor frequency, the nuclear quadrupole resonance (NQR) frequency is matched to the Rabi or Rabi plus Larmor frequency, as opposed to the Larmor frequency as is conventionally done. We derive expressions for the cross-polarization rate for all three conditions in terms of the relevant secular dipolar Hamiltonian, and demonstrate with these expressions how to measure the strength of the heterogenous dipolar coupling using only low magnetic fields. In addition, the combination of different resonance conditions permits the measurement of the spin-1/2 angular momentum vector using spin-1 NQR, opening up an alternate modality for the monitoring of low-field nuclear magnetic resonance. We use ammonium nitrate to explore these resonance conditions, and furthermore use the oscillating field to increase the signal-to-noise ratio per time by a factor of 3.5 for NQR detection of this substance.

Homozygous point mutations in platelet glycoprotein ITGA2B gene as cause of Glanzmann thrombasthenia in 2 families.

Glanzmann thrombasthenia (GT) is a rare autosomal recessive bleeding disorder characterized by quantitative and/or qualitative defects of the platelet glycoprotein (GP) IIb/IIIa complex. Physiologically, the integrin GPIIb/IIIa binds Von Willebrand factor and fibrinogen on activated platelets. GT is caused by genetic alterations in ITGA2B or ITGB3 (genes encoding GPIIb and GPIIIa).This study describes 2 siblings diagnosed with GT type I associated with homozygous point mutations in ITGA2B. All patients presented with typical bleeding disorder including moderate hematomas, petechiae, and mucocutaneous bleedings.Both siblings showed severely reduced platelet aggregation especially after stimulation with collagen and adenosine diphosphate. Absence of platelet GPIIb/GPIIIa complex was determined using flow cytometry. Molecular genetic analysis revealed 2 distinct homozygous point mutations in exon 18 of ITGA2B. Family 1 was identified with c.1878G>C and family 2 with c.1787T>C substitution. While the c.1787T>C mutation causes a single amino acid substitution p.I565T, the c.1878G>C mutation (p.Q595H) is predicted to induce a mRNA splicing anomaly.These mutations were identified as cause of GT type I in the described patients. Patients with GT should be documented in a prospective register to verify the correlation between the severity of bleeding symptoms and the pathogenic mutation. This can have effects on therapeutic decisions.

Neuropsychological assessment in mixed connective tissue disease: comparison with systemic lupus erythematosus.

OBJECTIVE: The aims of the study were to assess cognitive functions (CF) in patients with mixed connective tissue disease (MCTD) and to compare MCTD patients with systemic lupus erythematosus patients with and without neuropsychiatric manifestations (NP-SLE and non-NP-SLE, respectively) in terms of CF. METHODS: Neuropsychological examination was performed in 141 patients: 30 with MCTD (24 women, 6 men), mean age: 48.07 years, 37 with non-NP-SLE (36 women, 1 man), mean age: 40.76 years and 74 with NP-SLE (68 women, 6 men), mean age: 41.97 years. Neuropsychological tests and structured interview were used. Emotional state was assessed by Hospital Anxiety and Depression Scale and clinical review. RESULTS: We observed cognitive impairment in six MCTD patients (20%); in one (3%) the impairment was severe. MCTD patients achieved significantly higher results in seven out of 11 tests compared with patients with NP-SLE. MCTD and non-NP-SLE patients did not differ significantly. The differences were irrespective of premorbid IQ, education, disease duration and steroid treatment. CONCLUSIONS: In the majority of MCTD patients, CF were not impaired and severe impairment was unusual. Cognitive functioning was most disturbed in NP-SLE. The cognitive deficits observed in connective tissue diseases can be connected with nervous system involvement.

Allogeneic hematopoietic stem cell transplantation in Glanzmann thrombasthenia complicated by platelet alloimmunization.

BACKGROUND: For Thrombasthenia Glanzmann (GT) patients presenting with a severe clinical phenotype due to complete lack of thrombocyte function or increased titres of anti-platelet antibodies hematopoietic stem cell transplantation (SCT) is the only curative therapy. CASE REPORT: We report the case of a 13-month-old boy, presenting with a severe course of GT, who was successfully treated with an HLA-identical sibling bone marrow transplant. SCT was complicated by anti-platelet alloimmunization after platelet transfusion successfully treated with high dosage immunoglobulins (2 g/kg) and partial plasma exchange. CONCLUSION: SCT may be a viable option for selected patients with GT. However, SCT in GT carries its own significant risks, resulting from the development of anti-platelet antibodies. A critical risk-benefit analysis is mandatory prior to SCT.

Neuropsychological assessment in systemic lupus erythematosus patients: clinical usefulness of first-choice diagnostic tests in detecting cognitive impairment and preliminary diagnosis of neuropsychiatric lupus.

OBJECTIVES: To evaluate the usefulness of neuropsychological tests in order to distinguish the first-choice methods useful in quick detection of cognitive impairment in SLE and preliminary diagnosis of neuropsychiatric manifestation. Study aimed at assessment of the prevalence and severity of cognitive deficits in SLE patients and comparison between SLE patients with neuropsychiatric manifestations (NP-SLE) and without ones (non-NP-SLE). METHODS: 93 out of 104 SLE patients, 57 with NP-SLE and 36 with non-NP-SLE underwent comprehensive neuropsychological examination. Tailor-made structured interview for neuropsychological assessment in SLE (SISLE) was used. Patients' emotional state was assessed by clinical interview and HADS. RESULTS: Cognitive dysfunction was identified in 57% of SLE patients, 48.4% in 1-3 tests, 8.6% (8 patients) in 4 or more tests (severe decline). Among impaired patients 15% had severe decline. In NP-SLE group 63.2% were impaired vs. 47.2% in non-NP-SLE group. All 8 patients with severe decline were NP-SLE. The dysfunction was irrespective of premorbid intellectual level, age, education, disease duration and steroid treatment. In NP-SLE significantly lower scores were observed in 8 tests (10 parameters). CONCLUSIONS: Cognitive dysfunction is frequent in SLE patients. The majority of patients has mild deficits, but severe decline is also observed. The dysfunction is more frequent and more pronounced in NP-SLE. The study distinguished 8-test-first-choicebattery useful in detecting cognitive impairment in SLE and in case of severe decline - in preliminary differentiating NP-SLE and non-NP-SLE. Structured interview for psychological/neuropsychological examination of SLE patients is a useful and required tool for a standard patients' assessment.

Montelukast does not prevent reactive airway disease in young children hospitalized for RSV bronchiolitis.

AIM: To evaluate the long-term effect of montelukast on symptoms of cough and wheeze following RSV bronchiolitis. METHODS: Fifty eight patients (aged < or = 24 months) hospitalized with a first episode of RSV bronchiolitis were enrolled in this double blind prospective randomized trial comparing montelukast (n = 31) vs placebo (n = 27). RESULTS: During the 3-month treatment period, there were no statistical significant differences between the two groups for symptom-free days and nights (48.5 [interquartile range 33.0.0-66.0] for montelukast vs 57.0 [29.0-71.0] for placebo p = 0.415) nor disease-free days and nights (44.5 days [26.0-54.0] vs 53.0 [22.3-71.0]; p = 0.266). During the 1 year follow-up, there were 41 exacerbations in the montelukast group vs 54 exacerbations in the placebo group (p = 0.57). Time to first exacerbation was not different. Number of unscheduled visits and need to start inhaled steroids were comparable in the two groups. CONCLUSION: Treatment with montelukast after hospital admission for RSV bronchiolitis in children younger than 2 years of age did not reduce symptoms of cough and wheeze. We cannot exclude that a subgroup of children may, however, benefit from this treatment.

Low-field approach to double resonance in nuclear quadrupole resonance of spin-1 nuclei.

Using double-resonance conditions, in which the Larmor frequency of a spin-1/2 nucleus is matched to one of the nuclear quadrupole resonance frequencies of a spin-1 nucleus, the authors demonstrate increased cross relaxation between the two nuclear spin species. They calculate the cross-relaxation rate using the motionally averaged heterogeneous dipole Hamiltonian as a perturbation to the combined quadrupole and Zeeman Hamiltonians. Using this cross-relaxation rate, in addition to hydrogen and nitrogen autorelaxation rates, expressions governing spin-1/2 and spin-1 spin-lattice relaxation are determined. With ammonium nitrate, containing nitrogen (spin-1) and hydrogen (spin-1/2), increased nitrogen signal and spin-lattice relaxation are demonstrated, using fields less than 120 G. The cross-relaxation rate is also measured and an overall signal/noise improvement by a factor of 2.3+/-0.1 is attained.

[Palliative sedation]. / Palliative Sedierung.

Terminal illnesses can cause distressing symptoms such as severe pain, mental confusions, feelings of suffocation, and agitation. Despite skilled palliative care in some cases these symptoms may not respond to standard interventions. After all other means to provide comfort and relief to a dying patient have been tried and are unsuccessful, clinical caregivers and patients can consider palliative sedation. Sedation in the context of palliative medicine is the monitored use of medications to induce varying degrees of unconsciousness to bring about a state of decreased or absent awareness in order to relieve the burden of otherwise refractory suffering. Palliative sedation is not intended to cause death or shorten life. The patient and family should agree with plans for palliative sedation. Because cases involving palliative sedation are emotionally stressful, the patient, family, and health care workers can all benefit from talking about the complex medical, ethical, and emotional issues they raise.

Tobacco smoking problem in a group of 18-year-old high school students in the city of Gdansk--finding causes and preventive methods.

PURPOSE: The aim of the study was to evaluate smoking prevalence among 18-year-old secondary school students as well as their awareness of systemic health threats of smoking. Our goal was also to discuss the youth smoking risk factors and effective ways both to prevent and fight smoking problem. MATERIAL AND METHODS: 1516 18-year-old students (808 men, 708 women) from randomly selected 12 high schools were studied. The adolescents fulfilled the anonymus questionaire. RESULTS: 34.1% (517) of all participants smoke every day or occasionally, with the highest percentage of smokers in vocational schools (49.6%); women are the most frequent smokers (52.8%). The lower prevalence of smoking was observed in high schools (21.2% of men, 20% of women). In technical high schools 36.1% of men and 11.1% of women were smokers. The habitual smokers were found in all schools; the highest percentage was observed in vocational schools (32.75%-33.13%). The percentage was particularly high among women (33.13%). 92.09% of studied women and 89.95% of men were aware of smoking systemic health threats (93.84% of high school students, 88.25% of vocational school students). CONCLUSIONS: It is alarming that the percentage of smokers among 18-year-old students is high, in particular among women and vocational schools students. The results indicate that smoking is a serious problem in this population. It is vital to create the preventing and educating programmes addressed especially to adolescents. There is a need of future studies aimed to evaluate smoking risk factors and create effective methods of prevention as well as smoking cessation help resources.

Empathy in health care providers--validation study of the Polish version of the Jefferson Scale of Empathy.

PURPOSE: Empathy as a crucial component of the interpersonal relationship needs to be measured, especially in helping professions. We designed this study to adapt both "Student" ("S") Version and "Health Professionals" ("HP") Version of the Jefferson Scale of Empathy (JSE) to Polish population. MATERIAL AND METHOD: Three instruments were administered to 405 respondents: Polish version of the JSE, Interpersonal Reactivity Index (IRI) measuring four aspects of empathy (i.e. empathic concern, fantasy, personal distress and perspective taking), Emotional Intelligence Scale (EIS). JSE was applied to physicians, nurses and medical, nursing and midwives students in order to calculate reliability coefficient and other psychometric data. In order to assess validity of the scale, the empathy results were correlated with those obtained by respondents on IRI and EIS. RESULTS: Cronbach alpha reliability coefficient for "S" verSION WAS 0.73, for "HP" version - 0.79, whereas for the entire sample was 0.71. Neither significant differences on empathy scores were found between genders nor among five groups of respondents on JSE. Physicians obtained the highest mean of empathy score (M = 113.06), while the lowest was observed in nurses (M = 110.12). Empathy results on JSE correlated significantly with "empathic concern" (r = 0.25, p < 0.01) and with "perspective taking" (r = 0.26, p < 0.01). Also significant correlation was found between empathy and emotional intelligence. CONCLUSIONS: Despite the lower (but acceptable) reliability coefficient of the Polish JSE in comparison with the original version, the scale proved to be very useful instrument evaluating empathy in health care professionals and students. Further research is needed to identify factors that contribute to changes in psychometric data of the scale.

Calcium influences cellular and extracellular product formation during biofilm-associated growth of a marine Pseudoalteromonas sp.

Bacteria undergo a variety of physiological changes following a switch from planktonic growth to surface-associated biofilm growth. Here, it is shown that biofilm development of a marine isolate, Pseudoalteromonas sp. 1398, results in global changes in its cytosolic and extracellular proteomes. Calcium influences these proteome responses, and affects the amount of surface-associated biomass and extracellular matrix material produced by Pseudoalteromonas sp. 1398. Four extracellular proteins, characterized by N-terminal sequencing, showed increased abundances, while one protein, flagellin, showed reduced abundance at higher [Ca(2+)]. Immunoblotting and transmission-electron-microscopy analysis confirmed that higher [Ca(2+)] and surface-associated growth results in the repression of flagella production. Two-dimensional gel electrophoresis (2DGE) studies combined with cluster analysis of global proteome responses demonstrated that Ca(2+) had a greater regulatory influence on Pseudoalteromonas sp. growing in biofilms than on planktonic cultures. Approximately 22 % of the total cytosolic proteins resolved by 2DGE had differing abundances in response to a switch from planktonic growth to surface-associated growth when the cells were cultivated in 1 mM Ca(2+). At higher [Ca(2+)] this number increased to 38 %. Fifteen cellular proteins that were differentially expressed in response to biofilm growth and/or Ca(2+) were analysed by N-terminal sequencing and/or MS/MS. These proteins were identified as factors involved in cellular metabolic functions, putative proteases and transport proteins, although there were several proteins that had not been previously characterized. These results indicate that Ca(2+) causes global changes in matrix material, as well as in cellular and extracellular protein profiles of Pseudoalteromonas sp. 1398. These changes are more pronounced when the bacterium grows in biofilms than when it grows in planktonic culture.

Tunable atomic magnetometer for detection of radio-frequency magnetic fields.

We describe an alkali-metal magnetometer for detection of weak magnetic fields in the radio-frequency (rf) range. High sensitivity is achieved by tuning the Zeeman resonance of alkali atoms to the rf frequency and partially suppressing spin-exchange collisions in the alkali-metal vapor. We demonstrate magnetic field sensitivity of 2 fT/Hz(1/2) at a frequency of 99 kHz with a resonance width of 400 Hz. We also derive a simple analytic expression for the fundamental limit on the sensitivity of the rf magnetometer and show that a sensitivity of about 0.01 fT/Hz(1/2) can be achieved in a practical system with a measurement volume of 200 cm3.

Direct reconstruction of kinetic parameter images from dynamic PET data.

Our goal in this paper is the estimation of kinetic model parameters for each voxel corresponding to a dense three-dimensional (3-D) positron emission tomography (PET) image. Typically, the activity images are first reconstructed from PET sinogram frames at each measurement time, and then the kinetic parameters are estimated by fitting a model to the reconstructed time-activity response of each voxel. However, this "indirect" approach to kinetic parameter estimation tends to reduce signal-to-noise ratio (SNR) because of the requirement that the sinogram data be divided into individual time frames. In 1985, Carson and Lange proposed, but did not implement, a method based on the expectation-maximization (EM) algorithm for direct parametric reconstruction. The approach is "direct" because it estimates the optimal kinetic parameters directly from the sinogram data, without an intermediate reconstruction step. However, direct voxel-wise parametric reconstruction remained a challenge due to the unsolved complexities of inversion and spatial regularization. In this paper, we demonstrate and evaluate a new and efficient method for direct voxel-wise reconstruction of kinetic parameter images using all frames of the PET data. The direct parametric image reconstruction is formulated in a Bayesian framework, and uses the parametric iterative coordinate descent (PICD) algorithm to solve the resulting optimization problem. The PICD algorithm is computationally efficient and is implemented with spatial regularization in the domain of the physiologically relevant parameters. Our experimental simulations of a rat head imaged in a working small animal scanner indicate that direct parametric reconstruction can substantially reduce root-mean-squared error (RMSE) in the estimation of kinetic parameters, as compared to indirect methods, without appreciably increasing computation.