Fabrication and mechanical properties of PLLA/PCL/HA composites via a biomimetic, dip coating, and hot compression procedure.

Currently, the bone-repair biomaterials market is dominated by high modulus metals and their alloys. The problem of stress-shielding, which results from elastic modulus mismatch between these metallic materials and natural bone, has stimulated increasing research into the development of polymer-ceramic composite materials that can more closely match the modulus of bone. In this study, we prepared poly(L: -lactic acid)/hydroxyapatite/poly(epsilon-caprolactone) (PLLA/HA/PCL) composites via a four-step process, which includes surface etching of the fiber, the deposition of the HA coating onto the PLLA fibers through immersion in simulated body fluid (SBF), PCL coating through a dip-coating process, and hot compression molding. The initial HA-coated PLLA fiber had a homogeneous and continuous coating with a gradient structure. The effects of HA: PCL ratio and molding temperature on flexural mechanical properties were studied and both were shown to be important to mechanical properties. Mechanical results showed that at low molding temperatures and up to an HA: PCL volume ratio of 1, the flexural strain decreased while the flexural modulus and strength increased. At higher mold temperatures with a lower viscosity of the PCL a HA: PCL ratio of 1.6 gave similar properties. The process successfully produced composites with flexural moduli near the lower range of bone. Such composites may have clinical use for load bearing bone fixation.

Travelling to China for the Beijing 2008 Olympic Games.

The Beijing Olympics will be the world's premier sporting event in 2008. Countries should begin planning for appropriate support for their Olympic athletes. Experienced medical staff should be appointed early and become familiar with the major medical or injury concerns of athletes and officials. Teams should assemble a comprehensive medical kit. Appropriate medical advice can ensure that athletes will arrive in Beijing in optimal condition. Medical issues particularly relevant to competitors at the Beijing Olympics include heat and humidity, waterborne diseases and air pollution. However, the air pollution probably represents less of a threat than previous media reports would indicate. The Olympic village and venues can be thought of as small enclaves located within a rapidly developing country.

Remotely-delivered cognitive remediation in multiple sclerosis (MS): protocol and results from a pilot study.

BACKGROUND: Cognitive impairment represents a critical unmet treatment need in multiple sclerosis (MS). Cognitive remediation is promising but traditionally requires multiple clinic visits to access treatment. Computer-based programs provide remote access to intensive and individually-adapted training. OBJECTIVE: Our goal was to develop a protocol for remotely-supervised cognitive remediation that enables individuals with MS to participate from home while maintaining the standards for clinical study. METHODS: MS participants (n = 20) were randomized to either an active cognitive remediation program (n = 11) or a control condition of ordinary computer games (n = 9). Participants were provided study laptops to complete training for five days per week over 12 weeks, targeting a total of 30 hours. Treatment effects were measured with composite change via scores of a repeated neuropsychological battery. RESULTS: Compliance was high with an average of 25.0 hours of program use (80% of the target) and did not differ between conditions (25.7 vs. 24.2 mean hours, p = 0.80). The active vs. control participants significantly improved in both the cognitive measures (mean composite z-score change of 0.46 ± 0.59 improvement vs. -0.14 ± 0.48 decline, p = 0.02) and motor tasks (mean composite z-score change of 0.40 ± 0.71improvement vs. -0.64 ± 0.73 decline, p = 0.005). CONCLUSIONS: Remotely-supervised cognitive remediation is feasible for clinical study with potential for meaningful benefit in MS.

The cytochemistry of acute leukemia: a diagnostic and prognostic evaluation.

A combination of cytomorphological features and cytochemical staining reactions in the diagnoses of the different types of acute leukemia removes much of the subjective difficulty of diagnosis. The number of cytochemical stains used may be limited, and in our experience the PAS, combined NCE and ANE reactions, and either SB or Px staining will yield as much diagnostic information as needed in most cases. With regard to the prognostic implications, it would appear at the present time that the amount of ANE staining in the cytoplasm of blasts is inversely proportional to the chances of remission induction and length of survival in cases of acute leukemia. However, further studies must be carried out to verify this finding before using the information to compliment other prognostic variables, such as age of patient, previous therapy, cytokinetics, etc.

Monocytic leukemias.

The monocytic leukemias may be subdivided into acute monocytic leukemia, acute myelomonocytic leukemia, and subacute and chronic myelomonocytic leukemia. The clinical features of acute monocytic and acute myelomonocytic leukemias are similar and are manifestations of bone marrow failure. Gingival hypertrophy and skin infiltration are more frequent in acute monocytic leukemia. Cytomorphologically the blast cells in acute monocytic leukemia may be undifferentiated or differentiated, whereas in the acute myelomonocytic variety there are mixed populations of monocytic and myeloblastic cells. Cytochemical characteristics include strongly positive reactions for nonspecific esterase, inhibited by fluoride. The functional characteristics of acute monocytic and acute myelomonocytic cells resemble those of monocytes and include glass adherence and phagocytoses, the presence of Fc receptors for IgG and C'3, and the production of colony stimulating activity. Subacute and chronic myelomonocytic leukemias are insidious and slowly progressive diseases characterized by anemia and peripheral blood monocytosis. Atypical monocytes called paramyeloid cells are characteristic. The drugs used in the treatment of acute monocytic and acute myelomonocytic leukemias include cytosine arabinoside, the anthracyclines, and VP 16-213. Drug therapy in subacute and chronic myelomonocytic leukemias is not usually indicated, although VP 16-213 has been claimed to be effective.

Acute lymphocytic leukemia with atypical cytochemical features.

In a series of 78 cases of acute lymphocytic leukemia, seven were found to demonstrate blast cells staining strongly for both the periodic acid-Schiff reaction and alpha-naphthyl acetate esterase. It is suggested that these features may represent a subclassification of acute lymphocytic leukemia or may be a marker for the leukemic phase of lymphoma.

Clinical trials with diglycoaldehyde (NSC-118994): review and reasons for withdrawal from clinical trial.

All Phase II studies with diglycoaldehyde with leukemia and solid tumors have been reviewed. The dose schedules employed ranged from 1.5 to 2.0 g/m2/day for 3 to 5 days. The most common side effects have been gastrointestinal (nausea and vomiting), which occurred in 22% of the patients. Renal toxicity (rise in BUN, creatinine, and urinary proteins) was seem in 17% of the patients treated. Other infrequent toxicities include hypocalcemia (9%) and local complications such as phlebitis. Leukopenia, thrombocytopenia, positive Coombs' test and impairment in coagulation profile were also reported. In contrast to the hints of therapeutic efficacy described during Phase I trials, in phase II trials no activity was noted among 96 patients with solid tumors and only minimal antileukemic action among 49 other patients. These disappointing Phase II trials coupled with prominent toxicities have prompted the decision to terminate further clinical testing. This report summarizes all clinical observations as an example of circumstances which curtail clinical testing of anticancer drugs.

Oat cell carcinoma of the esophagus: unusual radiological appearances.

Primary oat cell carcinoma of the esophagus is a very rare tumour. The radiographic appearance of the three cases described in this paper are unusual because they resemble benign lesions such as leiomyoma, fibrous polyp and candidiasis. It would be interesting to investigate whether such an unusual appearance is common for this neoplasm.

Capillary viscometer for use with crosslinking polymer melts.

A capillary viscometer is described which adapts a conventional capillary rheometer for use with crosslinking polymers. Illustrative data obtained with the viscometer using diallyl phthalate resin are included.

Accidental poisoning in children: a psychosocial study.

Fifty pre-school children thought to have ingested potentially poisonous substances were studied, together with 50 controls. An interview of each child and mother was undertaken in the home situation. Seven at-risk factors make a child more likely to ingest a toxic substance. These are: greater accommodation changes by the family, father having had a large number of jobs, paternal past history of accidents, child's exploring ability, child's past history of poisonings, an abnormal appetite in children older than two years old and lower stimulation indices in 2-5 year-olds. Attention is drawn to the similarity between many of these factors and childhood abuse and neglect.

Influence of pretreatment on the surface characteristics of PLLA fibers and subsequent hydroxyapatite coating.

A fibrous precursor for bone repair composites was made by coating poly(L-lactide) (PLLA) fibers with hydroxyapatite (HA) using a biomimetic method. To enhance the bonding between the HA coating and the PLLA fiber, PLLA fibers were etched with either sodium hydroxide or sodium hypochlorite to generate carboxyl groups on fiber surfaces. The experiments were designed to determine the influence of etching on the fiber surface morphology and chemistry as well as the subsequent HA coating on the etched fiber surfaces. It was found that the etching pretreatment increased the roughness as well as the hydrophilicity of fibers, indicating that hydrolysis of PLLA chains had taken place on fiber surfaces. The etching pretreatment also promoted HA coating formation by introducing thicker coating on the surface of fibers with a longer etching time, a higher etching concentration, or with NaOCl as the etching agent. A mechanism of surface hydrolysis and oxidation of PLLA was proposed.

Influence of temperature and aging time on HA synthesized by the hydrothermal method.

The influence of temperature and aging time on the morphology and mechanical properties of nano-sized hydroxyapatite (HA) synthesized by a hydrothermal method is reported here. The pre-mixed reactants were poured into a stirred autoclave and reacted at temperatures between 25-250 degrees C for 2-10 h. HA powders thus obtained were examined using X-ray diffraction (XRD), high-resolution field emission scanning electron microscopy (FESEM) and a particle size analyzer. It was found that the aspect ratio of the particles increased with the reaction temperature. The length of the HA particles increased with the reaction temperature below 170 degrees C, but it decreased when the temperature was raised above 170 degrees C. The agglomerates of HA particles were formed during synthesis, and their sizes were strongly dependent on reaction temperatures. As the reaction temperature increased, the agglomerate size decreased (p = 0.008). The density of the discs pressed from these samples reached 85-90% of the theoretical density after sintering at 1200 degrees C for 1 h. No decomposition to other calcium phosphates was detected at this sintering temperature. A correlation existed (p = 0.05) between the agglomerate sizes of HA particles synthesized at various conditions and their sintered densities. With the increase of the agglomerate size, the sintered density of the HA compact decreased. It was found that both the sintered density and flexural strength increased with increasing aging time and reaction temperature. A maximum flexural strength of 78 MPa was observed for the samples synthesized at 170 degrees C for 5 h with the predicted average at these conditions being 65 MPa. These samples attained an average sintered density of 88%.

The distinctive features of acute monocytic leukemia.

Acute monocytic leukemia is an uncommon form of acute leukemia. Distinctive clinical features include gingival hypertrophy, lymphoadenopathy, coagulation disorders, and lysozymuria. Blast cell morphology and cytochemistry are diagnostic. Receptors for the Fc fragment of IgG have been demonstrated on the basis of a few cases. The drug VP 16-213 has been shown to be very effective in treatment of untreated and previously treated patients.

Lack of prognostic value of the periodic acid-Schiff reaction and blast cell size in childhood acute lymphocytic leukemia.

Conflicting evidence has been published as to the prognostic significance of the periodic acid-Schiff (PAS) reaction and cell size in acute lymphocytic leukemia (ALL). Therefore, a large collaborative study was undertaken to evaluate the prognostic significance of the PAS reaction and cell size of bone marrow lymphoblasts obtained at the time of diagnosis in children with ALL. Known prognostic factors (age and white blood cell [WBC] counts) were also evaluated. Data from 80 newly diagnosed cases of ALL were analyzed. These patients were treated with similar therapy by members of the Pediatric Division of the Southwest Oncology Group. The PAS reaction was scored. Microlymphoblasts were defined as having a diameter of less than or equal to 12 micron; macrolymphoblasts, greater than 12 micron. Patients 10 years and older at the time of diagnosis had a significantly shorter duration of first remission and survival than those younger than 10 years. Those with pretreatment peripheral WBCs of less than or equal to 25,000/microliter had significantly longer duration of first remission and survival than those with a peripheral WBC greater than 25,000/microliter. There was no significant difference in duration of first remission or survival in patients having predominantly macrolymphoblastic or microlymphoblastic marrows. PAS reaction was of no value in predicting the duration of first remission or survival.

Cutaneous Hodgkin's disease in a patient with human immunodeficiency virus infection.

A 22-year-old man with human immunodeficiency virus infection had skin nodules of the chest wall. When a biopsy was performed on these nodules, Hodgkin's disease was discovered. The patient was subsequently found to have widespread disease involving the lymph nodes and liver. Skin involvement with Hodgkin's disease is rare. In this report, we review previous descriptions of skin involvement appearing in the literature.