In vivo XCT bone characterization of lattice structured implants fabricated by additive manufacturing

Several cylindrical specimens and dental implants, presenting diagonal lattice structures with different cell sizes (600, 900 and 1200 μm) were additively manufactured by selective laser melting process. Then they were implanted for two months in a sheep. After removal, they were studied by Archimedes’ method as well as X-ray computed tomography in order to assess the penetration of bone into the lattice. We observed that the additive manufactured parts were geometrically conformed to the theoretical specifications. However, several particles were left adhering to the surface of the lattice, thereby partly or entirely obstructing the cells. Nevertheless, bone penetration was clearly visible. We conclude that the 900 μm lattice cell size is more favourable to bone penetration than the 1200 μm lattice cell size, as the bone penetration is 84% for 900 μm against 54% for 1200 μm cell structures. The lower bone penetration value for the 1200 μm lattice cell could possibly be attributed to the short residence time in the sheep. Our results lead to the conclusion that lattice implants additively manufactured by selective laser melting enable better bone integration.

A phase I/II (P1/P2) study of AT-101 in combination with topotecan (T) in patients with relapsed or refractory small cell lung cancer (SCLC) after prior platinum-containing first-line chemotherapy

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Background: Bcl-2 family proteins are expressed in SCLC and are associated with chemotherapy resistance. AT-101 is an oral, pan Bcl-2 family protein inhibitor (Bcl-2, Bcl-XL, Mcl-1, and Bcl-w) and potent inducer of proapoptotic proteins. AT-101 has demonstrated activity in SCLC models, including those that express Mcl-1 and are resistant to other Bcl-2 inhibitors. The P1 portion of the study was previously reported. Methods: Pts ≥18 years of age, PS 0–1, with relapsed or refractory SCLC after first line chemotherapy with measurable disease per RECIST were eligible. Pts were stratified into 2 cohorts; cohort A ≥ 60 days and cohort B < 60 days relapse from prior chemotherapy and treated with T 1.25 mg/m2 daily and AT-101 40 mgs daily on days 1–5, q21 along with the use of myeloid growth factors. Adverse Events (AEs) were graded by the NCI CTCAE v. 3.0. Efficacy assessments (RECIST) were performed every 6-weeks. A 2-stage design was used with power/alpha of 80%/0.05 to detect a RR of > 25% and > 5%, in cohort A and B respectively. Results: 36 pts enrolled: ages 41–76; cohort A/B 23/13. The PR/SD/PD/NE rates were 17%/70%/9%/4% and 8%/54%/23%/15%, in cohorts A/B respectively. The median times to progression (TTP) were 18 and 13 weeks, respectively. The most common (>20 %) AEs (all grades): anemia (64%); neutropenia (53%); nausea (47%); fatigue (44%); thrombocytopenia (42%); dyspnoea (25%); and vomiting (22%). Most common Grade 3/4 related events (>5%): neutropenia (31%); thrombocytopenia (25%); anemia (14%); and asthenia (6%). No ileus was reported. Conclusions: AT-101 can be safely combined with T. The observed toxicities were consistent with the known rates of G4 cytopenias of T alone. The response rates observed did not meet the criteria for additional enrolment; however, many patients had a best response of SD and the median TTP in both cohorts was favorable compared to historical controls. Additional trials of AT-101 in SCLC are ongoing.

[Table: see text]

Homozygous mutations in ARIX(PHOX2A) result in congenital fibrosis of the extraocular muscles type 2

Isolated strabismus affects 1-5% of the general population. Most forms of strabismus are multifactorial in origin; although there is probably an inherited component, the genetics of these disorders remain unclear. The congenital fibrosis syndromes (CFS) represent a subset of monogenic isolated strabismic disorders that are characterized by restrictive ophthalmoplegia, and include congenital fibrosis of the extraocular muscles (CFEOM) and Duane syndrome (DURS). Neuropathologic studies indicate that these disorders may result from the maldevelopment of the oculomotor (nIII), trochlear (nIV) and abducens (nVI) cranial nerve nuclei. To date, five CFS loci have been mapped (FEOM1, FEOM2, FEOM3, DURS1 and DURS2), but no genes have been identified. Here, we report three mutations in ARIX (also known as PHOX2A) in four CFEOM2 pedigrees. ARIX encodes a homeodomain transcription factor protein previously shown to be required for nIII/nIV development in mouse and zebrafish. Two of the mutations are predicted to disrupt splicing, whereas the third alters an amino acid within the conserved brachyury-like domain. These findings confirm the hypothesis that CFEOM2 results from the abnormal development of nIII/nIV (ref. 7) and emphasize a critical role for ARIX in the development of these midbrain motor nuclei.

[Arteriovenous malformations in the jaws. The place of intravascular therapy. Apropos of 14 cases]

PURPOSE

To analyze arteriovenous malformations (AVMs) of maxillo-mandibular arcades seen in our department since 1977, and to determine adequate treatment.

MATERIAL AND METHODS

Fourteen AVMs were reviewed to determine their revelation, their semiology, the treatment applied and the results that could be obtained. All these lesions were true AV shunts involving bone with or without soft tissue extension.

RESULTS

Eight patients belonged to the pediatric population. Six lesions were maxillary and 8 mandibular. All lesions were revealed during or after puberty by local swelling, pain, mass effect or bruit. Hemorrhage was the most frequent (71%) symptom. Teeth instability was detected in all these patients and was origin of the bleeding. The lesions were suspected clinically and confirmed radiologically. Angiography analyzed properly the architecture of the lesion (4 arteriovenous fistulas). Embolization was the clinical treatment in all patients: particles helped to stabilize the acute situations but failed to offer stable results, necessitating complementary embolizations and/or surgery (hemimandibulectomy in 2 patients). The use of acrylic glue (Histoacryl), injected percutaneously (5 patients), or transarterially in the AVM (4 patients)) provided cure in 6 of these lesions (43%) and long term stabilization for all the other AVMs. Teeth extraction could be performed thereafter in good conditions. Antibiotics and anti-inflammatory treatment helped to stabilize the evolutive risk of these lesions.

CONCLUSION

Embolization is the therapy of choice in these lesions. Appropriate use of glue offers a high rate of cure and/or clinical stabilizations and avoids unneeded surgery.

A cost analysis comparing erythropoietin and red cell transfusions in the treatment of anemia of prematurity

BACKGROUND

Anemia of prematurity is invariably observed in very low birth weight infants and may become symptomatic enough to be treated with packed red cell transfusions. Recently, treatment of this condition with recombinant human erythropoietin has been advocated.

STUDY DESIGN AND METHODS

To compare the costs of training symptomatic anemia in hospitalized premature infants with transfusions alone or with erythropoietin plus red cell transfusions as needed, cost estimates were derived from local hospital and published cost data. Decision analysis and sensitivity analysis were applied to a "base case." The base case was derived from results of a multicenter erythropoietin trial in the United States in which premature infants received 500 U of erythropoietin per kg of body weight each week. Because erythropoietin treatment began on average at 3 weeks of life, when infants were clinically stable, they had already received 3.5 red cell transfusions. During the 6-week treatment period, erythropoietin-treated infants received significantly fewer additional transfusions: a mean of 1.6 versus 1.1.

RESULTS

The base-case cost in 1993 dollars for treating anemia in hospitalized premature infants with erythropoietin and transfusions was $1,326. This was nearly twice the cost of conventional treatment with transfusions alone ($721). If the 6-week treatment period alone is considered, erythropoietin is 3.6 times more costly: $840 versus $235.

CONCLUSION

The largest available US study using erythropoietin to treat anemia in premature infants has demonstrated a small, but significant, reduction in transfusion needs. However, this study's cost data alone do not justify the widespread use of erythropoietin in premature infants. When this issue is probed in great depth, sensitivity analyses demonstrate that major reductions in erythropoietin's cost and/or improvements in its effectiveness quite possibly will make its use economically more attractive.

A, B, and H substances in syringomas. An immunohistochemical analysis of 15 cases

This study examines the distribution of A, B, and H substances in 15 syringomas and 11 control axillary skins. Monoclonal antibodies (MCABs) against A, B, and H substances with the avidin-biotin-peroxidase complex (ABC) method were used. Additionally, the H antigen was localized with Ulex europaeus Agglutinin-I (UEA-I) by use of the peroxidase-antiperoxidase method. The MCABs provided specific and reproducible staining of all 15 syringomas as well as the secretory coli and duct of normal eccrine glands. Contrariwise, apocrine and sebaceous glands were uniformly nonreactive. The staining by the UEA-I technique showed a similar pattern to that of the anti-H MCAB but with increased background (nonspecific) staining. These results, using state-of-the-art immunohistochemistry, confirm the eccrine origin of syringoma. Blood group substances may be useful in distinguishing other tumors of eccrine origin from those of apocrine origin.

Fatty acid synthesis in rat fetuses with intrauterine growth retardation

The effect of uterine artery ligation at 17 days of gestation to induce intrauterine growth retardation (IUGR) on fetal fatty acid synthesis was studied in pregnant rats. Significant impairment in fatty acid synthesis was observed in fetal liver and lung tissues. The specific activity of fatty acids at 19 days of gestation in the liver was lower in the IUGR rats, as compared to controls, 44.6 +/- 13 versus 87.9 +/- 10 cpm/mumol fatty acids (p less than .05). At 21 days of gestation, the specific activity of fatty acids was 40.6 +/- 7.8 as compared to 75.8 +/- 9.8 cpm/mumole in the IUGR and control fetuses, respectively (p less than .05). In lung, the specific activity of fatty acids was 25.7 +/- 5.4 cmp/mumole in IUGR fetuses as compared to 46.6 +/- 9 cpm/mumole in control littermates at 19 days (p less than .05). This difference persisted at 21 days since the specific activity was 32.2 +/- 2.4 in experimental fetuses as compared to 42.6 +/- 3.0 cpm/mumole in controls (p less than .05). Brain and placental tissues demonstrated no statistically significant differences in specific activity at either time in gestation. The total fatty acid content per organ for both liver and lung was also reduced in the IUGR group. Decreased substrate transfer from mother to fetus during placental insufficiency may account for decreased lipogenesis in the IUGR fetus. Brain and placental tissues are spread despite significant compromises in liver and lung capabilities for fatty acid synthesis.

The use of a single fronto-zygomatic osteosynthesis plate and a sinus balloon in the repair of fractures of the lateral middle third of the face

In certain orbito-zygomatic fractures, a fronto-zygomatic screwed plate and a sinus balloon permit, at the expense of a single eyebrow incision, the repositioning of the cheekbone and the alignment of the other fracture sites; the other fractures sites consolidate and remodel themselves spontaneously due to the action of the adjacent soft tissues. The plate is malleable so that correct reduction can occur during the course of surgical repair; the plate should align the cheekbone perfectly. Neglect of the stability offered by reduction after exposure of the bone fragments may seem exaggerated, in simple cases; the orbital approach is without risk and limited. This argument - which also depends on the experience of the surgeon - does not apply in the case with a comminution of the orbital rim; closed fracture site reduction and distant osteosynthesis offer an alternative to the classical repair which requires a wide cutaneous incision and significant periosteal stripping with the subsequent risk of eyelid distortion.

Effect of quinacrine on nuclear structure and RNA synthesis in cultured rat hepatocytes

The effects of quinacrine, an antimetabolite which intercalates into DNA, on the ultrastructure of interphase nuclei and on RNA turnover were studied in primary cultures of rat hepatocytes. Procedures included ultrastructural cytochemical staining for ribonucleoprotein and DNA, autoradiography, and measurement of labeled uridine uptake and incorporation. Addition to the culture medium of a nontoxic dose (10 microM for 30 min) reduces the net accumulation of labeled uridine in RNA. This involves first heterogeneous RNA and then ribosomal RNA since their structural precursors, interchromatin fibrils and nucleolar fibrils, respectively, diminish in that order. Intranucleolar chromatin retracts, and perinucleolar chromatin becomes unusually condensed. A toxic dose (50 microM for 30 min) produces greater inhibition of tritiated uridine incorporation in RNA. This precedes and is not due to a drop in uridine uptake into the cells. Toxic doses produce unusually large clusters of interchromatin granules which are embedded in an unusual dense material which stains positively for ribonucleoprotein. Three regions of the chromatin are altered. (a) Perinuclear condensed chromatin retracts from the nuclear envelope, remaining attached by short DNA-containing bridges. (b) The normally dispersed nucleoplasmic chromatin condenses into a stainable network which retracts centrifugally. (c) Perinucleolar chromatin becomes a network of small highly condensed masses or bands interconnected by fibrils which are either decondensed or stretched. These alterations in chromatin structure probably form the basis of quinacrine-impaired nuclear metabolism.

Fractures of the frontal sinus

Fractures of the frontal sinus are frequently seen in patients with cranio-facial injuries. Trauma to the posterior wall and more deeply located tissues: anterior fossa, dura and brain, give an indication of the seriousness of such injuries. We point out some particular aspects of our experience; in the neurosurgical approach to such lesions; we use a classification based on treatment: -when the posterior wall of the sinus is not, or only slightly damaged, we drain it using a thin suction catheter pulled through the fronto-nasal duct, kept in place for six to ten days. -when a comminuted fracture of the frontal arch occurs in the sinus area, a large cortico-cancellous onlay bone graft is used to rebuild a harmonious frontal contour and avoid the risk of secondary deformity.

[Effects of trauma to the facial bones on the anterior shelf of the base of the skull (author's transl)]

The different types of fractures of the upper jaw and facial bones and their extension to the anterior wall of the frontal sinus are discussed. Possible effects on the bony floor of the anterior shelf of the base of the skull and subjacent meninges are outlined. These injuries are then reviewed as part of the larger picture of lesions of the middle third of the craniofacial region. Several types can be distinguished:I.--Lesions in the anterior wall of the frontal sinus only, II.--Lesions affecting the base of the facial bones, III.--Lesions in the frontal vault radiating to the base, IV.--Direct lesions of the middle third, V.--Isolated lesions from back-lash or distortion, VI.--External fronto-orbital impactions. Only types 2, 3, 4, and 5 affect the middle third of the endocranial region. As far as the risk of fistula formation is concerned, facial lesions (type 2) have a good prognosis, while frontal lesions (type 3, 4, and 5) have a poor prognosis. This criterium can assist in making decisions, after superficial examination of the lesions, whether to employ major surgery or not in a deep, difficult region.

[Frontobasal injuries and csf fistulas. Attempt at an anatomoclinical classification. Therapeutic incidence]

The authors present a classification of trauma to the cranial base, based on observation in 80 cases. There are five types. Type I : involves only the anterior wall of the frontal sinus. Type II : involves the face (craniofacial disjunction of the Lefort II type or crush face) and extend upward to the cranial base and, in occurency, to the anterior wall of the frontal sinus, because of the facial retrusion. Type III : ivolves frontal part of the skull and extend down to the cranial base. Type IV : is a combination of types II and III. Type V : involves only ethmoidal or sphenoidal bones. Cerebrospinal fluid leak is unfrequent in types II, and transitionnal, if it occurs ; but it often occurs in types III, IV and V which include in every case a dural tear. Correct diagnosis facilitates treatment. Fractures of types I and II can be fully treated by maxillo-facial surgeons, whereas for types III, IV, and V, they need the help of a neuro-surgeon.