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This paper presents the technique used for converting a 3D ArtCAM™ relief file into the stereolithography (STL) format. This 3D file is obtained from a 2D picture using a 3D CNC engraving software called ArtCAM™.: The problem is to convert the 3D relief files into an STL format without compromising the accuracy and details of therelief. This paper discusses the size of the files which have been converted, and steps taken to reduce the file size by reducing the number of triangles or facets in the STL file. The discussion involves the verification of the converted model by comparing it with the original relief. The problems associated with the reduction of triangles when the file has been converted to STL format are also discussed.

Fusarium, a fungus, produces a potent mycotoxin that, when ingested with contaminated cereal grains, produces a serious illness in man called alimentary toxic aleukia (USSR) and Akakabi-byo (Japan). The illness includes gastrointestinal symptoms and weakness and, if ingestion of Fusariumcontaminated grain persists, culminates in aplastic anemia. A 66-year-old woman had Eaton-Lambert syndrome and a clinical course similar to alimentary toxic aleukia. Several months before her death, pancytopenia, initially thought guanidine-induced, developed and progressed to aplastic anemia despite discontinuation of guanidine 2 months before death. Autopsy showed numerous granuloma in the liver, spleen, esophagus, and cecum from which Fusarium oxysporumwas isolated. Although the unique finding of systemic fusariosis may relate to altered host resistance terminally, a causal relationship with her defect of neuromuscular transmission and/or aplastic anemia is a distinct possibility.

Mycoplasma pulmonis, a pathogen of the respiratory tract in rats, was inoculated intracerebrally into neonate rats and hamsters to determine if it would induce lesions in the ependyma. Hydrocephalus was induced in 116 of 120 rats and in 23 of 28 hamsters. The severity of hydrocephalus was greater in the rats than in the hamsters. Hydrocephalus induction occurred only subsequent to inoculation of viable M. pulmonis. At 2 weeks of age, rats became refractory to induction of hydrocephalus. Light microscopy indicated that the hydrocephalus was communicating without an inflammatory response in the ventricles and meninges. Preliminary electron microscopy revealed that amorphous material covered portions of the ependymal surface and that cilia were sometimes matted together. It was suggested that the hydrocephalus was due to ciliary dysfunction or to an imbalance of cerebrospinal fluid secretion and absorption. This M. pulmonis-induced hydrocephalus may be a useful model for elucidating the pathogenesis of certain types of congenital hydrocephalus in humans.

Contrary to contention that Onuf nucleus is spared in Werdnig-Hoffmann disease (WHD) as it is in ALS, we found central chromatolysis in the Onuf neurons of the sacral cord from all five WHD patients. They were less depopulated but the central chromatolysis appeared more frequently than in anterior motor neurons. In contrast, the sacral autonomic neurons were not affected in any of the five cases. This argues against the view that the Onuf nucleus is autonomic and is spared with other autonomic neurons.

N-Butyl benzenesulfonamide (NBBS), a plasticizer used commercially in the polymerization of polyamide compounds, is neurotoxic. Young adult New Zealand white rabbits, inoculated repeatedly with NBBS by the intracisternal or intraperitoneal routes, developed a dose-dependent motor dysfunction characterized by limb splaying, hyperreflexia, hypertonia, gait impairment, and abnormal righting reflexes. Histopathological changes consisted of intramedullary thickening of the ventral horn axons, random neuroaxonal spheroids confined to brain stem nuclei and spinal motor neurons, and swollen dendritic processes of spinal motor neurons. Immunoreactivity to a monoclonal antibody against microtubule-associated protein-2 (MAP-2) was markedly increased in the dendrites of spinal motor neurons following thrice weekly intraperitoneal inoculations of NBBS for 4 months, whereas after 12 monthly intracisternal inoculations. MAP-2 immunoreactivity was absent or strikingly reduced in the same neuronal populations. Ultrastructurally, postsynaptic zones contained vacuoles and multilamellar bodies. These findings raise questions about the safety of NBBS to humans.

Hydrocephalic neonates were observed in a small breeding colony of rats. Normal rats from this colony were obtained and brother-sister mated for seven generations. The overall prevalence of hydrocephalics was approximately 23%; however, in one subline, the prevalence approached 50%. Breeding data suggested the trait to be polygenic. Hydrocephalics could be detected at 1–2 days of age, and survived for 4–5 weeks. Dilatation of the ventricles was restricted to the lateral ventricles. No evidence of developmental anomalies was seen within the ventricles. Preliminary evidence suggested that the pathophysiology may be related to poorly developed veins in the periosteal-dural layers and to underdeveloped pia-arachnoid cells. The hydrocephalus was classified as being of the communicating type.

A patient with chronic Leigh's necrotizing encephalomyelopathy also had cardiomyopathy and a prominent “mitochondria1 myopathy.” It is speculated that (1) muscle often may be involved in Leigh's disease and might serve as an important tissue for biochemical investigation, (2) certain “neurodegenerative disorders” known in the literature by other terms actually may be Leigh's disease, and (3) similar bizzarre mitochondria may be of more than secondary importance in other disease entities.

Myositis induced by Coxsackie A4 and A9 viruses was investigated in the gastrocnemius muscles of suckling mice and adult mice with denervation. Denervation markedly increased the susceptibility of adult mice to Coxsackie A virus infection, and this effect was initiated as early as 1 day after denervation. Light microscopy demonstrated inflammation and necrosis in the denervated gastrocnemius muscle of adult mice, whereas muscle from the contralateral leg showed only infrequent, mild, focal myositis. Ultrastructually, crystalline arrays of virus particles were seen in the infected muscle fibers and in the phagocytes of both suckling and adult mice. Nuclear alterations, especially in the myotubes, and a characteristic compound membrane-vesicle complex (CMVC) in the sarcoplasm, developed simultaneously. Replicating and fusing myoblasts, activated as part of the regenerative process after denervation, appeared to be closely associated with the susceptibility of muscle to Coxsackie A virus infection.

Abstract This study is carried out to develop a direct link between a laser digitiser and a rapid prototyping system for biomedical applications. Two CAD/CAM systems, DUCT and Pro-Engineer, are investigated and the DUCT system is found to be more suitable for this purpose. A laser digitiser is used to capture three-dimensional surface data for the object. With the aid of the CAD/CAM system, the data can be manipulated in a number of ways for display, modification and enhancement. In addition, the object scanned by the laser digitiser can be physically produced relatively quickly and accurately using StereoLithography Apparatus (SLA), a leading rapid prototyping system. Feasible and practical solutions to the problems encountered in the CAD surface model construction are proposed and illustrated. Two case studies, a facial and a breast model, are presented. Results show that this integrated approach can be applied effectively in the biomedical field.

Abstract Each rapid prototyping (RP) process has its special and unique advantages and disadvantages. The paper presents a state-of-the-art study of RP technologies and classifies broadly all the different types of rapid prototyping methods. Subsequently, the fundamental principles and technological limitations of different methods of RP are closely examined. A comparison of the present and ultimate performance of the rapid prototyping processes is made so as to highlight the possibility of future improvements for a new generation of RP systems.

Fast transport of intra-axonal organelles was studied in motor nerve from amyotrophic lateral sclerosis (ALS) patients. Organelle traffic in ALS nerves demonstrated a significant increase in anterograde mean speed, while retrograde mean speed was decreased compared with that of controls. Retrograde traffic density (organelles per unit time) was also significantly decreased in the ALS specimens. Anterograde transport machinery is therefore intact and may be responding to the increased physiologic demand of larger motor units. Diminished retrograde speed and organelle traffic density are consistent with a defect in retrograde transport and could impair communication between axon terminals and perikarya.

To examine the neural influence upon fiber type differentiation in developing muscles, newborn rats were subjected to sciatic nerve dissection, and the denervated extensor digitorum longus (EDL) (white) and soleus (red) muscles were examined in chronologic sequence by means of histochemistry and electron microscopy. The skeletal muscles in the newborn rats were undifferentiated (type 2C fibers seen on ATPase staining) and contained numerous myotubes. In the controls, the type 2C fibers started to differentiate at around 5 days and had almost completed type differentiation by 30 days in EDL and by 90 days in soleus muscles. On the other hand, none of the fibers in the neonatally denervated muscles developed into well differentiated type 1 and 2A fibers, but both the EDL and soleus showed longlasting type 2C and 2B populations. The satellite cells in the denervated EDL and soleus muscles decreased in number at the same rate as in the control muscles with maturation. The absence of a neural supply in the developing muscles induced a delay in muscle fiber type differentiation but did not influence the satellite cell populations in either EDL or soleus muscles.

Light and electron microscopic study and morphometric analysis were performed on the spinal cords and roots from six cases of acute Werdnig-Hoffmann disease and four control cases, in search of the pathogenesis of the selective motor neuron changes considered primarily responsible for Werdnig-Hoffmann disease. This investigation posits a centrifugal traction mechanism based upon the discovery of cylindrical outgrowths of glial bundles, selective loss of large myelinated fibers, and axonal degeneration in the proximal portion of anterior spinal roots (and to a lesser extent in posterior spinal roots) in all six disease cases. This traction mechanism exerts principally upon anterior spinal nerve roots and can account for morphologic and morphometric data characteristically ascribed to Werdnig-Hoffmann disease.

Two herpes-like viruses were isolated from capuchin monkey (Cebus apella) brain and (Cebus albifrons) spleen cell cultures, respectively. Both isolates induced similar cytopathic effects consisting of rounded and ballooned cells in the original monkey cell cultures and in a wide range of permissive cell types. Neutralizing antibody to each virus was present in serum from the capuchin monkey from which it was isolated, but the two viruses did not cross-react by neutralization. Fluorescein isothiocyanate conjugates of hyperimmune rabbit serum to one of the isolates showed an antigenic cross relationship between the two isolates. By electron microscopy, herpes-like virus particles were observed in the nucleus and cytoplasm of infected human diploid fibroblast cell cultures. Virus-infected cell cultures stained with acridine orange revealed small deoxyribonucleic acid-containing intranuclear inclusion bodies. Both viruses were inhibited by 5-fluorodeoxyuridine and inactivated by chloroform or exposure to 56 degrees C for 30 min. Antisera prepared against 16 prototype herpesviruses and cytomegaloviruses did not neutralize approximately 100 50% tissue culture infective doses of either capuchin isolate. Neutralizing antibody to the capuchin isolates was detected in sera from 8 of 17 capuchin monkeys but not in sera from 16 humans, 15 chimpanzees, and 10 spider, 6 rhesus, and 5 squirrel monkeys.

By using a chemically defined medium, a general and highly specific procedure was devised to select for mutant cells with less abundant or structurally altered sterol in their surface membranes. Within a certain concentration range, the polyene antibiotic filipin was shown to kill only cells with normal (as opposed to decreased) membrane sterol levels. Sterol-requiring derivatives of LM cells were isolated by chemical mutagenesis, filipin treatment, and cloning followed by replica plating in soft agar. Mutants (S1 and S2) are described which, when compared to normal cells, show decreased synthesis of demosterol in vivofrom acetate and mevalonate relative to cell number or to fatty acid synthesis. When exogenous sterol is supplied, mutants S1 and S2 grow normally in suspension culture. However, when deprived of sterol supplement, mutant S1 grows slower than wild type cells and mutant S2 lyses within one to two generations. Gas/liquid chromatography revealed that the mutants contained a normal spectrum of fatty acids including unsaturated fatty acyl groups but, unlike wildtype cells, they have less abundant (mutant S1) or no (mutant S2) desmosterol in either the presence or absence of exogenous cholesterol. In vitroexperiments with mevalonate as the substrate suggest that the defect in both mutants is in a demethylation reaction subsequent to lanosterol synthesis. The selection method developed here may permit the isolation of mutants with defective membrane incorporation of sterols and other polyisoprenoids as well as defective synthesis of these compounds.

This report describes the isolation in tissue culture of an adenovirus from the brain of a 42-year-old man dying with radiation-treated lymphosarcoma and a 4.5-week history of neurological disease which, on histopathological evidence, was diagnosed as subacute encephalitis.The isolate, designated the JL strain, was most closely related antigenically to Ad. 32 by NT test and to Ad. 27 by HI test. Type-specific antisera to 31 additional adenoviruses failed to show significant neutralizing or hem-agglutination-inhibiting relationships. Similarly, antisera prepared in rabbits and monkeys inoculated with the JL strain neutralized only homologous virus and Ad. 32 and inhibited hemagglutination of the homologous virus and Ad. 27 to a significant titer.

Bizarre configurations of muscle mitochondria containing paracrystalline inclusions were demonstrated in a clinically and pathologically typical case of chronic polymyositis with Raynaud's syndrome. The probable mechanism of formation of these abnormal mitochondria was discussed. From the accompanied alterations in the same fibers, i.e. focal assembly of sarcoplasmic reticulum, membranous profiles, miniature mitochondria, and vesicular nuclei with prominent nucleoli, the overall phenomena were interpreted as a process of atypical regeneration.

THYROTROPIN hormone deficiency is the rarest of all single pituitary tropic hormone deficiencies.1 Only 11 cases have been reported.1-8 The thyroid stimulating hormone (TSH) test has been helpful in evaluating the majority of these cases.6 However, the recent availability of reliable bioassay tests for anterior pituitary hormones has made the diagnosis of this disorder more precise. The majority of cases have not shown the usual signs and symptoms of myxedema. This was true of the patient of this report who showed a peripheral neuropathy. REPORT OF A CASE This 45-year-old white woman was observed since October 1964. She complained of paresthesias in both hands and feet which slowly progressed over the past six to seven years. This was described as burning, numbness, tingling, and stiffness. Symptoms began first in the feet and a few years later involved the hands and fingers. The paresthesias in the feet

Autoradiography was performed in order to envisage the turnover of H3-leucin labeled protein in the perikarya of spinal motoneurons and in the axonal balloons formed after repeated administrations of IDPN (ß-ß'-iminodiproprionitrile) in rats.

Numerous periodic-acid-Schiff positive plaques occurred in the cerebellum of a patient diagnosed as having Creutzfeldt-Jakob disease. Microscopic and submicroscopic structures of the plaques were identical with those described in Kuru. This is an additional link between these two neurological diseases in which the clinical, histopathological, and virological features are in many respects similar.

THE FINDINGS of a deficiency of β-D-N-acetylhexosaminidase component A in Tay-Sachs disease1 and β-galactosidase in generalized gangliosidosis2 provide us a plausible explanation for different, GM1 and GM2, ganglioside accumulation in these diseases. Furthermore, the fact that these enzymes are localized in lysosomes sheds light as to why the stored lipoid materials are constantly associated with lysosomal or lipofuscin components of neurons on electron microscopy.3-10 It is conceivable that a deficiency of different enzymes involved in the catabolism of gangliosides may be involved in various clinical subtypes of amaurotic idiocy. As of this date, six clinical subtypes of amaurotic idiocy have been recognized: (1) congenital,11,12 (2) infantile,13,14 (3) late infantile,15,16 (4) systemic late infantile,17,18 (5) juvenile,19-21 and (6) adult.22In 1925, Kufs22 described the first patient with the adult variety of Tay-Sachs disease whose neurologic symptoms started at

In order to improve the aging behavior of piezo-ceramics, sintering of PZT ceramics under direct current field has been studied. The experimental results show that while a D.C. field is applied to the sample during sintering, the sintered ceramic sample will exhibit piezoeiectric properties before poling, and its rate of aging of piezoelectric coupling factor will be improved. The causes of difference between the rate of aging of dielectric constant and that of piezoelectric coupling factor have also been discussed. It appears that for a given ceramic composition the internal stresses presented in the ceramic szmple play an important role i n the rate of aging of piezoelectric coupling factor, whereas the ratio of c/a axes of the ceramic sample after poling is the predominant factor for influencing the rate of aging of the dielectric constant.

Brain tissue from seven patients with progressive multifocal leukoencephalopathy was tested for the presence of papovaviruses. IC virus, a human papovavirus, was identified in all seven cases. Virus was isolated in tissue culture from extracts from each of four patients and was detected by immunofluorescence in sections from the other three. The new isolates were indistinguishable from the prototypical IC strain serologically and in all biological characteristics examined. Thus IC virus has, to date, been associated with 20 cases of progressive multifocal leukoencephalopathy.