Coil embolization versus clipping for ruptured intracranial aneurysms: a meta-analysis of prospective controlled published studies.

BACKGROUND AND PURPOSE: Coil embolization is an alternative to clipping for intracranial aneurysms. However, controversy exists regarding the best therapeutic strategy in patients with ruptured aneurysms, and there is great center- and country-related variability in the rates of clipping versus coiling. We performed a meta-analysis of prospective controlled trials of clipping versus coil embolization for ruptured aneurysms. MATERIALS AND METHODS: We performed a search of the English literature for published prospective controlled trials comparing surgical clipping with endovascular coil embolization for ruptured intracranial aneurysms. Data were abstracted from the identified references. Outcomes of interest were the proportion of patients with a poor outcome at 1 year and episodes of rebleeding from the index treated aneurysm after the allocated treatment. RESULTS: There were 3 prospective controlled trials eligible for inclusion. These studies enrolled 2723 patients. Meta-analysis of these studies showed that the rate of poor outcome at 1 year was significantly lower in patients allocated to coil embolization (risk ratio, 0.75; 95% confidence interval, 0.65-0.87). This relative effect is consistent with an absolute risk reduction of 7.8% and a number needed to treat of 13. The effect on mortality was not statistically different across the 2 treatments. Rebleeding rates within the first month were higher in patients allocated to endovascular coil embolization. CONCLUSIONS: On the basis of the analysis of the 3 high-quality prospective controlled trials available, there is strong evidence to indicate that endovascular coil embolization is associated with better outcomes compared with surgical clipping in patients amenable to either therapeutic strategy.

Coiling for paraclinoid aneurysms: time to make way for flow diverters?

BACKGROUND AND PURPOSE: Paraclinoid aneurysms represent challenging lesions for which endovascular techniques have gained widespread application in their treatment. A new endovascular strategy, flow diversion, is gaining importance in the treatment of these aneurysms. Before embracing flow diversion in larger numbers of patients with paraclinoid aneurysms, it is important to know the safety and efficacy of "traditional" endovascular methods for these aneurysms. We review complications and outcomes of patients with unruptured paraclinoid aneurysms treated with coils, with or without balloon and stent assistance, over the past 12 years at our institution. MATERIALS AND METHODS: A retrospective review of 118 patients with 126 unruptured paraclinoid aneurysms, treated between 1999 and 2010, was performed. Clinical records, endovascular reports, angiographic results, and clinical outcomes were reviewed and analyzed. RESULTS: Fifty-nine percent of aneurysms were carotid-ophthalmic, 27% were hypophyseal, 9% were posterior carotid wall, 3% were carotid cave, and 2% were transitional. Twenty-one percent of aneurysms were symptomatic, and 3% were recurrent aneurysms after previous treatment. Fifty (40%) were treated with balloon assistance and 18 (14%) with stent assistance. Technical complications causing permanent morbidity occurred in 1 patient (0.8%), while early clinical complications causing transient morbidity occurred in 5 (4%) patients. Complete occlusion was achieved in 40% of aneurysms immediately after treatment and in 66 (62%) aneurysms during follow-up (mean 31.9 ± 28.4 months). Recurrences occurred in 18 patients (17%) and 10 (9%) patients were retreated. Clinical outcome was good in 95% and poor in 5% of the 107 patients with follow-up (mean 37.0 ± 33.7 months). Only in 1 patient was poor outcome related to the endovascular procedure. Transient ischemic attacks occurred in 4% of patients. No cases of rebleeding were observed during follow-up. CONCLUSIONS: Modern endovascular coil treatment of unruptured paraclinoid aneurysms appears safe, with satisfactory, although not ideal, rates of complete occlusion. The introduction of flow diverters will probably increase the rate of complete angiographic occlusion, but this must be achieved with low complication rates.

Endovascular treatment of ruptured paraclinoid aneurysms: results, complications, and follow-up.

BACKGROUND AND PURPOSE: Paraclinoid aneurysms are an uncommon cause of aneurysmal SAH, and their treatment is challenging. To assess the effectiveness and safety of endovascular treatment of ruptured paraclinoid aneurysms, we performed a retrospective analysis of 33 patients. MATERIALS AND METHODS: Clinical and radiologic information on 33 patients undergoing endovascular therapy between 1999 and 2010 was retrospectively reviewed. Angiographic results were evaluated with the modified Raymond grading system, whereas clinical outcomes were evaluated with the mRS scale. RESULTS: Seventeen (52%) aneurysms were classified as clinoid segment aneurysms, and 16 (48%), as ophthalmic segment aneurysms. Twenty-six (79%) aneurysms were small, 6 (18%) were large, 1 was (3%) giant, and 39% were wide-neck. Coiling was done with balloon assistance in 36% of cases and stent-assistance in 6%. Technical complications occurred in 1 patient, contributing to death. Early clinical complications causing permanent disability occurred in 3% of cases. One patient (3%) had fatal rebleeding 18 days after treatment. Overall, procedure-related morbidity and mortality were, respectively, 3% and 6%. Complete occlusion of the aneurysm was achieved in 36% of patients after initial treatment and in 65% during follow-up (average, 29.3 months). Seven patients had recurrences requiring retreatment (30%). Clinical outcome (average, 32.9 months) was good in 75% of patients and poor in 25%. No delayed complications related to treatment and/or the aneurysm occurred. CONCLUSIONS: Ruptured paraclinoid aneurysms are challenging lesions from an endovascular and surgical point of view. Despite the high rate of recurrences, good clinical results and protection against rebleeding can be achieved with current endovascular techniques.

Airborne particulate matter and gaseous air pollutants in residential structures in Lodi province, Italy.

UNLABELLED: The province of Lodi is located in northern Italy on the Po River plain, where high background levels of air pollutants are prevalent. Lodi province is characterized by intensive agriculture, notably animal husbandry. This paper assesses indoor levels of selected airborne pollutants in 60 homes in the province, with special attention to size-fractionated particulate matter (PM). Indoor PM2.5 concentrations are frequently higher than current guidelines. PM10 and nitrogen dioxide also exceed the respective guideline recommendations in some cases, noting that 24-h nitrogen dioxide levels were compared with an annual limit value. All other studied pollutant levels are below current international guidelines. Among indoor PM size fractions, PM0.5 is predominant in terms of mass concentrations corresponding to 57% of PM10 in summer and 71% in winter. A strong seasonal trend is observed for all studied pollutants, with higher levels in winter corresponding to changes in ambient concentrations. The seasonal variation in PM10 is largely due to PM0.5 increase from summer to winter. Summer indoor PM levels are mainly from indoor-generated particles, while particles of outdoor origin represent the main contribution to winter indoor PM levels. On average, indoor concentrations of coarse PM are mostly constituted by indoor-generated particles. PRACTICAL IMPLICATIONS: This study presents a comparison between measured indoor concentrations in the study area and indoor air quality guideline criteria. Accordingly, particulate matter (PM) and NO2 are identified as key pollutants that may pose health concerns. It is also found that indoor PM in residential units is mainly constituted by particles with aerodynamic diameters <0.5 µm, especially in winter. Risk mitigation strategies should be focused on the reduction in indoor levels of NO2 and ultrafine and fine particles, both infiltrated from outdoors and generated by indoor sources.

Levodopa effect on electromyographic activation patterns of tibialis anterior muscle during walking in Parkinson's disease.

Previous studies have reported that patients with Parkinson's disease (PD) show, in the "off medication" state, a reduced activation of tibialis anterior (TA) in the late swing-early stance phase of the gait cycle. In PD patients the pathophysiological picture may cause differences among the stride cycles. Our aims were to evaluate how frequently TA activity is reduced in the late swing-early stance phase and if there is a relationship between the TA pattern and the clinical picture. Thirty PD patients were studied 2 h after Levodopa administration ("on-med") and 12 h after Levodopa wash-out ("off-med"). They were evaluated by the Unified Parkinson's Disease Rating Scale (UPDRS III) and surface electromyography of TA and gastrocnemius medialis (GM). The root mean square (RMS) of the TA activity in late swing-early stance phase (RMS-A) was normalized as a percent of the RMS of the TA activity in late stance-early swing (RMS-B). RMS-A was reduced in 30% of patients in the "off-med" condition. Within these patients, the percentage of stride cycles with reduced RMS-A, ranged between 28% and 83%. After Levodopa intake, no stride cycle showed reduced RMS-A. Patients with reduced RMS-A had a lower UPDRS III total score in the "on-med" rather than in the "off-med" condition (p=0.02). Our data confirm and extend previous observations indicating that, in "off-med" the function of TA is impaired in those patients clinically more responsive to Levodopa. TA activation is reduced in a relatively high percent of gait cycles in the "off-med" state. Since the variability of TA activation disappears after Levodopa administration, this phenomenon could be the expression of an abnormal dopaminergic drive.

[Assessment of comfort and health status of Call Center's workers]. / La valutazione del comfort e dello stato di salute in lavoratori di un Call Center.

BACKGROUND: Call Centers are workplaces in which there are a lot of occupational health hazards. METHODS: The aim of the study was to investigate Call Center operators' health status, using: "Ambiente/Salute" questionnaire, VHI questionnaire, health surveillance data analysis. RESULTS: "Negative" Microclimate rating: 68%; "negative" noise rating: 51%. "Negative" eye symptoms rating: 30%; "negative" postural disorders rating: 21%. "Negative" VHI value (over the limit of 30): 6%. CONCLUSIONS: It's necessary to develop and validate an appropriate health surveillance protocol

[Radon risk evaluation in a hospital context]. / Valutazione del rischio da Radon in una realtà ospedaliera.

Italian legislation imposes radon concentration in occupational, underground premises as to not exceed the annual action level of 500 Bq/m3. A survey in a hospital of Milan founded concentrations never exceeding the action level, distribute around the median concentration of 16 Bq/m3, ranging between 6 e 214 Bq/m3 (Cmean = 38 +/- 50 Bq/m3). However, a pavilion, characterized by higher levels (C = 103 divided by 214 Bq/m3), was better studied by short-term monitoring, during summer and winter, confirming concentrations not exceeding legislative level, even if not negligible. Results underlines the importance of a monitoring strategy as punctual as possible. Moreover, shortterm measurements can represent a valid tool for premises screening in radon monitoring.

Spontaneous carotid-cavernous fistula supplied by the contralateral meningohypophyseal trunk: case report and literature review.

Carotid-cavernous sinus fistulas (CCF) are abnormal communications between the carotid artery and the cavernous sinus. Most spontaneous CCFs are low-flow fistulas, supplied by branches of the omolateral internal carotid artery or the external carotid artery. A 64-year-old man, with increasing diplopia, mild exophthalmos on the left side, blurred left vision and omolateral red eye, was admitted to our institution. The patient underwent a bilateral cerebral angiography that showed a left CCF fed by meningo-hypophyseal branches of the right internal carotid artery and draining from the cavernous sinus into a parahippocampal vein. A transarterial embolization of the carotid-cavernous fistula was performed, with complete obliteration of the fistula. Although anecdotal reports exist, there is a scarcity of well-documented cases of exclusively contralateral flow in the carotid-cavernous fistula. Most of the reported cases referred to contralateral flow into the carotid-cavernous fistula by the external carotid artery branches. To the best of our knowledge, there are no previous cases of a spontaneous CCF supplied by contralateral meningo-hypophyseal branches. A discussion of treatment options and a literature review are also performed.

Extracranial aneurysms of the posterior inferior cerebellar artery. Literature review and report of a new case.

Aneurysms arising from the extracranial portion of the posterior-inferior cerebellar artery (PICA) are considered extremely rare. To date, only ten cases have been reported in the literature. The authors report a case of a 29 year-old male patient admitted comatose in Hunt-Hess grade IV because of an subarachnoid haemorrhage predominantly involving the left cranio-vertebral junction up to C2 rather than the posterior fossa and the fourth ventricle. Angiography showed an extracranial aneurysm at left vertebral artery-PICA junction a few millimetres superior to the dural entry point of the vertebral artery (VA). A left extreme-lateral approach was performed and the aneurysm was successfully clipped. On first year follow-up the patient had completely recovered with no neurological deficits. This paper analyzes the literature review about these rare aneurysms and the technical notes regarding the cranio-vertebral junction approach to these lesions. Factors affecting the neurological outcome of these aneurysms are also reported.

Alterations in CD4+, CD8+, Vgamma3, Vgammadelta, and/or Valpha betaT-lymphocyte expression in lymphoid tissues of progeny after in utero exposure to benzo(alpha)pyrene.

That benzo alpha)pyrene (Balpha P) decreases both humoral and cell-mediated immunity, and leads to increases in progeny tumor development after in utero insult, suggests that T- and B-lymphocytes are made defective in exposed offspring. In the study here, C3H mice were injected once with Balpha P (150 microg/g BW) at day 12 of pregnancy and progeny lymphoid tissues were excised during gestation (day 18; GD18) or at 1 or 6 weeks post-partum. The isolated lymphoid cells were analyzed by flow cytometry/immunofluorescence or assessed for function. In Balpha P-exposed fetuses, thymic Thy1(+) cell levels were decreased (relative to levels in organs of corn oil-exposed dam progeny). In addition, for up to 6 weeks post-birth, CD4(+)CD8(+) (double positive; DP) cells were virtually absent and levels of CD4(-)CD8(-) (double negative; DN) cells were consistently at epsilon 90%. With regard to single positive (SP) cells, CD4(+) cell levels were also decreased in tissues at GD18 up through 6 weeks post-birth; CD8(+) cell levels were increased, but only in pups at 1-week and 6-weeks post-birth. In 1-week-old progeny, spleen CD8(+) cell levels were quantitatively unchanged, though CD4(+) levels were reduced 2-4-fold and CD4(-)CD8(-) DN levels significantly increased. With respect to TCRs, fetal levels of thymic CD3Vgamma(3)(+) and CD3Vgamma delta(+) cells were decreased; levels of CD3Valphabeta cells were only slightly depressed. The latter results contrast sharply with a strong reduction in CD3Valphabeta cells in the fetal livers of Balpha P-exposed progeny. Interestingly, these livers also strongly evidenced a presence of BalphaP-7,8-dihydrodiol-9,10-epoxide metabolite. When assessed for any change in function, the CD4(+), Thy1(+) cells isolated from Balpha P-exposed progeny tissues responded weakly (relative to controls) to ConA and in an allogeneic MLR. Taken in totality, the results here strengthen our original hypothesis that BalphaP can create a favorable milieu for tumor growth progression in progeny of exposed mothers by affecting development of sufficient numbers of functional lymphocytes in the offspring.

Skin and cutaneous melanocytic lesion simulation in biomedical optics with multilayered phantoms.

The complex inner layered structure of skin influences the photon diffusion inside the cutaneous tissues and determines the reflectance spectra formation. Phantoms are very useful tools to understand the biophysical meaning of parameters involved in light propagation through the skin. To simulate the skin reflectance spectrum, we realized a multilayered skin-like phantom and a multilayered skin phantom with a melanoma-like phantom embedded inside. Materials used were Al(2)O(3) particles, melanin of sepia officinalis and a calibrator for haematology systems dispersed in transparent silicon. Components were optically characterized with indirect techniques. Reflectance phantom spectra were compared with average values of in vivo spectra acquired on a sample of 573 voluntary subjects and 132 pigmented lesions. The phantoms' reflectance spectra agreed with those measured in vivo, mimicking the optical behaviour of the human skin. Further, the phantoms were optically stable and easily manageable, and represented a valid resource in spectra formation comprehension, in diagnostic laser applications and simulation model implementation, such as the Monte Carlo code for non-homogeneous media.

[The optimization of the treatment and timing of the intervention by a nephrologist in pre-dialytic chronic renal insufficiency]. / L'ottimizzazione delle cure e il "timing" dell'intervento del nefrologo nell'insufficienza renale cronica pre-dialitica.

BACKGROUND: Early referral to nephrologists of patients with chronic renal failure (CRF) reduces morbidity and mortality in dialysis. Aim of this work is to evaluate the condition of early and late referral, and whether the two different conditions can affect the treatments. MATERIALS AND METHODS: This is a prospective study with a 12-month follow-up period. During this time, we verified the prevalence of patients with serum creatinine > 1.5 mg/dL (CRF patients) and the condition of early or late referral, defined as referral to nephrologists for > or < 3 times during follow up, respectively. Diagnosis of diabetes mellitus and/or arterial hypertension, and the use of antihypertensive drugs, insulin, hypoproteic diet and erythropoietin was recorded in each patient. RESULTS: CRF (mean serum creatinine value = 2.11+/-1.52 mg/dL) was observed in 190 patients aged 72.05+/-11.62 years. The prevalence of CRF was 4718 pmp. Diabetes and hypertension were diagnosed in 107 subjects (56.3%) and 152 subjects (80%), respectively. Only 74.2% (no. 141) of the patients with CRF was habitually followed by the nephrologist and the frequency was directly correlated to the degree of CRF: 100% of the patients with Creatinine Clearance (Cr Cl) < 25 mL/min, 70% with Cr Cl >25 < 50, and 0% with Cr Cl >50 < 80 mL/min. Early referral was coupled with a wider use of a hypoproteic diet, erythropietin, and the association ACE-I + Angiotensin II receptor antagonists. CONCLUSION: In conclusion, our data show a prevalence of CRF that is at least 5 times greater than that of dialysis patients. The condition of late referral is present in about 30% of the CRF population from the time of the initial phases of renal disease. Referral time affects the modalities of the treatment.

Immunomodulation in progeny from thymectomized primiparous mice exposed to benzo(a)pyrene during mid-pregnancy.

Previous studies have shown that Benzo(a)pyrene (B(a)P3) given to non-thymectomized (NTX) female mice alters expression of T cell subsets and suppresses cell mediated immunity (CMI) and humoral immunity (HI) in the progeny. Thus, maternal exposure to B(a)P may influence changes in progeny immune status. To understand how maternal cellular and humoral factors influence embryonic development of progeny immunity, adult female mice were thymectomized (TX) at 6 weeks, mated and injected with 150 microg B(a)P)/g body weight at 12 days of pregnancy. After B(a)P exposure, the following studies were performed: (A) Maternal reproductive capacity and survival rate of progeny; (B) Detection of T cells in progeny thymus; (C) Functional characteristics of progeny thymus or spleen. Maternal thymectomy and B(a)P exposure reduced average litter size by 40%. Serological sensitivity of thymus cells with anti-Thyl + complement occurred at a higher dilution of mAb in progeny from TX mothers exposed to B(a)P, suggesting that B(a)P-thymectomy led to increased sensitivity of developing thymocytes to mAb plus complement. Progeny from TX mothers exposed to B(a)P showed enhanced thymic CMI, but suppressed splenic CMI and HI. Thus, thymectomy prevents CMI immunosuppression by B(a)P, while HI is still suppressed. These results indicate that the maternal thymus is necessary for incurring the effect of B(a)P on progeny CMI.

Custom cranioplasty using stereolithography and acrylic.

Numerous methods of cranioplasty have been described. Customization and prefabrication have been reported to reduce operating time and improve cosmesis. An original technique for the manufacture of customized cranioplastic implants has been developed and tested in 30 patients.Thirty patients requiring cranioplasties were selected. Data acquired from computed tomography (CT) were used to manufacture exact plastic replicas (biomodels) of craniotomy defects and master cranioplastic implants using the rapid prototyping technology of stereolithography (SL). The three-dimensional (3D) imaging techniques of mirroring and interpolation were used to extrapolate on existing anatomy to design the master implants. The master implants were hand finished to fit the defect in the corresponding cranial biomodel exactly and were then used to create a cavity mould. The mould was used to cast thermally polymerised custom acrylic implants. The surgeons reported that the customized implants reduced operating time, afforded excellent cosmesis and were cost effective. The patients reported that the opportunity to see the biomodel and implant preoperatively improved their understanding of the procedure. Two complications were noted, one infection and one implant required significant trimming. The simultaneous manufacture of the master implant (male) and biomodel (female) components from SL allowed custom accurate implants to be manufactured. Disadvantages identified were the time required for computer manipulations of the CT data (up to 2 h), difficulty in assessing the accuracy of the computer generated master as a 3D rendering, the potential for SL parts to warp, manufacturing time (minimum 2 days) and the cost of approximately $1300 US per case ($1000 for the SL biomodel and $300 for the acrylic casting).

A method for the resection of cranial tumours and skull reconstruction.

A new technique for the resection of cranial tumours and subsequent reconstruction using stereolithographic (SL) biomodelling and customized cranioplastic implants has been developed. The technique is based on a custom model of the tumour and surrounding skull from which the resection of the tumour and shape of the cranioplasty can be determined. A patient with a hyperostotic fronto-orbital meningioma was selected. CT was performed and SL biomodels manufactured. The surgeon marked the resection margin on the biomodel and a customized resection template was fashioned. The tumour was then resected from the biomodel and a customized acrylic implant was manufactured to reconstruct the defect. At surgery the tumour was exposed in a routine fashion and the template used to mark the resection margin. Once resected, the defect was reconstructed with the custom cranioplastic implant. The technique facilitated accurate surgical resection of the tumour and subsequent reconstruction. The surgeon reported several advantages of the technique including increased confidence, reduced operating time (at least 1 h), excellent cosmetic results, accuracy, and simplicity. The patient reported that the opportunity to see the biomodel, template and implant improved her understanding of the procedure.

Cerebrovascular biomodelling: a technical note.

BACKGROUND: Recently computed tomographic angiography (CTA) and MR angiography (MRA) have been used to image cerebrovascular structures. Although CTA and MRA are accurate and sensitive imaging modalities, limitations have been identified in relation to image interpretation. Stereolithographic (SL) biomodelling is a new technology that allows three-dimensional (3D) CT and MR data to be used to accurately manufacture solid plastic replicas of anatomical structures. A prospective trial of SL biomodelling in cerebrovascular surgery has been performed to investigate the feasibility and clinical utility of this new display medium. METHODS: Fifteen patients with cerebral aneurysms and 1 patient with a cerebral arteriovenous malformation (AVM) were selected. 3D CT and/or MR angiograms were acquired and 19 solid anatomical biomodels manufactured using the rapid prototyping technology of stereolithography. The biomodels were used for patient education, diagnosis, operative planning and surgical navigation. RESULTS: The biomodels replicated the CTA and MRA source data. The accuracy of one biomodel was verified by comparison with a post mortem specimen, which corresponded exactly in the x and y planes but differed by 2 mm in the z plane. The ability to closely study an overview of complex cerebrovascular anatomy from any perspective on a solid biomodel was reported to enhance the surgeon's understanding, particularly when conventional images were equivocal. Cerebrovascular biomodels were found to be useful when positioning the patient's head for surgery, for selecting the best aneurysm clip and for the simulation of clipping. Patient informed consent was anecdotally improved. Disadvantages of the technology were the cost and manufacturing time. CONCLUSIONS: Cerebrovascular biomodelling may have utility in complex cases or when the standard imaging is felt to be equivocal.

Spinal biomodeling.

STUDY DESIGN: A prospective trial of stereolithographic biomodeling in complex spinal surgery. OBJECTIVES: To investigate the use of stereolithographic biomodeling as an aid to complex spinal surgery. SUMMARY OF BACKGROUND DATA: Of the array of imaging methods available to assist the spinal surgeon, no single method provides a complete overview of the anatomy, although three-dimensional imaging has been shown to have advantages. METHODS: Stereolithographic biomodeling is a new technology that allows data from three-dimensional computed tomographic scans to be used to generate exact plastic replicas of anatomic structures. Five patients with complex deformities were selected: two children with congenital deformities, a patient with an osteoblastoma, a patient with basilar invagination caused by osteogenesis imperfecta, and a patient with a failed lumbar fusion. Computed tomographic scanning was performed and stereolithographic biomodels generated. The stereolithographic biomodels were used for patient education, operative planning, and surgical navigation. RESULTS: The surgeons reported that biomodeling was useful in complex spinal surgery and was an effective technology. Stereolithographic biomodels were found to be particularly useful in morphologic assessment, in the planning and rehearsal of surgery, for intraoperative navigation, and for informing patients about surgical procedures. CONCLUSIONS: Stereolithographic biomodeling allows imaging data to be displayed in a physical form. This intuitive medium may improve data display and allows surgical simulation on a proxy of the surgical site. Draw-backs of the technology were a minimum 24 hours' manufacturing time and the cost.

Maternal exposure to benzo[a]pyrene alters development of T lymphocytes in offspring.

Childhood cancer has been increasing significantly over the past two decades in the United States, suggesting that environmental exposures may be playing a causative role. One such cause may be maternal smoking during pregnancy. Suspected carcinogens in cigarette smoke and environmental pollution include N-nitrosamines and polycyclic aromatic hydrocarbons, which may be several micrograms per exposure. Previously, we have shown that mouse progeny of mothers exposed to benzo[a]pyrene (B[a]P) during midpregnancy had abnormalities in their humoral and cell-mediated immune response. Immunodeficiency was detectable during gestation, at one week after birth and persisted for 18 months. Tumor incidences in progeny were eight to 10-fold higher than in controls. The present study compared frequencies of CD4+, CD8+, V gamma 2+, and V beta 8+ T cells in progeny following in utero exposure to B[a]P. The significant reduction in newborn CD4+CD8+, CD4+CD8+V beta 8+ thymocytes and CD4+ splenocytes from 1-week-old progeny, suggests that B[a]P induces abnormal changes in developing T cells. These early alterations may lead to postnatal T cell suppression, thus providing a more suitable environment for the growth of tumors later in life. These results suggest that developmental immunosuppression mediated by B[a]P may play a critical role in the relationship between maternal exposures and childhood carcinogenesis.

Biomodel-guided stereotaxy.

OBJECTIVES: To simplify the practice of stereotactic surgery by using an original method, apparatus, and solid anatomic replica for trajectory planning and to validate the method and apparatus in a laboratory and clinical trial. METHODS: The patient is marked with fiducials and scanned by using computed tomography or magnetic resonance imaging. The three-dimensional data are converted to a format acceptable to stereolithography. Stereolithography uses a laser to polymerize photosensitive resin into a solid plastic model (biomodel). Stereolithography can replicate blood vessels, soft tissue, tumor, and bone accurately (<0.8 mm). A stereotactic apparatus is referenced to fiducials replicated in the biomodel. The trajectory for the intervention is determined and saved. The apparatus is attached to the patient fiducials, and the intervention is replicated. RESULTS: Three types of apparatus (template, Brown-Roberts-Wells frame, and D'Urso frame) were tested on phantoms and patients requiring the excision/biopsy of tumors. The localization errors determined from the phantom studies were template, 0.82 mm; Brown-Roberts-Wells frame, 1.17 mm; and D'Urso frame, 0.89 mm. The surgeons reported that clinical use of the template and D'Urso frame was accurate and ergonomic. The Brown-Roberts-Wells frame was more difficult to use and somewhat inaccurate. CONCLUSION: Biomodel-guided stereotaxy has significant advantages. It is performed quickly; it is based on simple, intuitive methodology; it enhances visualization of anatomy and trajectory planning; it enhances patient understanding; it uses inexpensive equipment; it does not require rigid head fixation; and it has greater versatility than known techniques. Disadvantages are biomodel cost and a manufacturing time of 12 to 24 hours.

Stereolithographic modelling as an aid to orbital brachytherapy.

PURPOSE: This paper describes the technique of stereolithographic biomodelling and its application to a patient who was treated using orbital brachytherapy. METHODS AND MATERIALS: The process uses a moving laser beam, directed by a computer, to draw cross-sections of the model onto the surface of photo-curable liquid plastic. Using a stereolithographic apparatus (SLA), solid or surface data is sliced by software into very thin cross-sections. A helium cadmium (HeCd) laser then generates a small intense spot of ultraviolet (UV) light that is moved across the top of a vat of liquid photo monomer by a computerised optical scanning system. The laser polymerises the liquid into a solid where it touches, precisely printing each cross-section. A vertical elevator lowers the newly formed layer, and a recoating and levelling system establishes the next layer's thickness. Successive cross-sections (0.25 mm thick), each one adhering to the one below, are built one on top of the other, to form the part from the bottom up. The biomodel allowed the implant to be planned in detail prior to the surgery. The accurate placement of brachytherapy catheters was assured, and the dosimetry could be determined and optimised prior to the definitive procedure. CONCLUSIONS: Stereolithography is a useful technique in the area of orbital brachytherapy. It allows the implant to to be carried out with greater accuracy and confidence. For the patient, it minimises the risk to the eye and provides them with a greater understanding of the procedure.