SIMULTANEOUS EVALUATION OF P-v-T, ISOBARIC SPECIFIC HEAT AND JOULE - THOMSON COEFFICIENT MEASUREMENTS

A method is given in this paper that enables the simultaneous evaluation of P-v-T, isobaric specific heat and Joule - Thomson coefficient (J. T. C) measurements. It gives the ideal gas isobaric specific heat function and a semi-explicit v = v(P, T) equation of state (E. O. S) as results. The results for the vapor phase of R227 are presented also

METHOD FOR THE DETERMINATION OF HEAT AND MASS TRANSFER COEFFICIENTS IN THE CASE OF THROUGH-CIRCULATION DRYING OF LUCERNE*

The present paper deals with the determination method of the drying characteristics of lucerne. The determination principle of heat and mass transfer coefficients required for modelling the through-circulation drying process of a lucerne bed, on the basis of drying experiments, the calculation method of the so-called specific phase contact surfaces will be described here, in the knowledge of the preceding notions as well as of the volumetric transport coefficients. The transport characteristics, measured according to the above-mentioned principle and further the comparison of the measured and numerically calculated results of the drying process of an experimental lucerne bed will be discussed, too

Estudo microanatômico dos ramos corticais distais da artéria cerebral anterior

Os ramos corticais distais da artéria cerebral anterior são habitualmente as artérias orbito-frontal (AOf), fronto-polar (AFp), frontais internas anterior (AFIA), média (AFIM) e posterior (AFIP), do lóbulo paracentral (ALP), parietais internas superior (APIS) e inferior (APII) e artéria calosomarginal (ACm) . A distribuição destes ramos e suas variações têm importância clínica no tratamento das lesões vasculares da região inter-hemisférica. Foram estudados os ramos distais da ACA em 38 cérebros injetados com látex e dissecados sob magnificação. Os diâmetros e distâncias entre a origem dos vasos corticais distais e a ACoA foram analisados estatisticamente. O diâmetro médio da ACA após sua origem da ACoA foi de 2,61±0,34 mm e as médias dos diâmetoros das artérias corticais variou de 0,79±0,27 mm a 1, 84±0, 3 mm. As distâncias médias entre as origens de vários vasos e a ACoA variou de 7,68±3,91 mm (órbito-frontal) a 112,6±11,63 mm (parietal interna inferior). Variações anatômicas foram encontradas neste estudo: uma ACA ázigos estava presente em um caso e uma terceira ACA em 3. Em 26,3% dos casos, ramos cruzados da ACA distal suprindo o hemisfério contralateral foram encontrados. A presença de ramos cruzados da ACA distais à ACoA (artéria comunicante anterior) em 26,3% dos casos indica a importância desta variação anatômica quando se considera o diagnóstico e tratamento das lesões envolvendo a ACA. Nenhuma diferença estatisticamente significante foi encontrada entre os lados direito e esquerdo no padrão de ramificação, na distância entre a origem dos vasos e a ACoA e no calibre dos vasos.The distal branches of the ACA (anterior cerebral artery) are usually the orbitofrontal, frontopolar, anterior, middle and posterior internal frontal, paracentral lobe, the superior and inferior internal parietal arteries and the calosomarginal. The distribution of these branches and their variations have significant clinical importance in the treatment of vascular lesions of the interhemispheric region. The distal branches of the ACA in 38 brains injected with latex and dissected under magnification. The diameters and the distances between the origin of the distal cortical vessels and the anterior communicating artery were recorded and statistically analyzed. The average diameter of the ACA at origin was 2.61±0.34 mm and the average cortical branches diameter ranged from 0.79±0.27 mm to 1.84±0.3 mm. The average distances between the origin of the various vessels and the ACoA (anterior communicating artery) ranged from 7.68±3.91 mm (orbitofrontal) to 112.6±11.63 mm (inferior internal parietal). Anatomical variations were found in this study: an azigos ACA was present in one case anda triplicate ACA in 3. In 26.3% of the cases crossing branches of the distal ACA supplying the contralateral hemisphere were found. The presence of crossing branches of the ACA distal to the ACoA in 26.3% of the cases indicates the importance of this anatomic variation when considering the diagnosis and treatment of lesions involving the ACA. No statistically significant differences were found in the branching pattern, distance between the origin and the ACoA and caliber between the left and right sides

Tick-borne encephalitis : clinical and pathogenetic aspects

The aims of this study were to investigate the morbidity associated with tick-borne encephalitis (TBE) in the acute stage and at long-term follow-up, to identify the possible host risk factors for development of clinical TBE with special reference to the role of the genetic polymorphism, and to investigate neurochemical changes in the brain induced by TBE virus (TBEV) and their possible role on severity of TBE with special reference to endogenous kynurenic acid (KYNA). Paper I: Of 250 consecutively admitted patients with central nervous system (CNS) infections treated during a 1-year period, all 133 patients with TBE participated in the prospective follow-up study. TBE presented as mild (meningeal), moderate or severe (encephalitic) forms in 43.6%, 43.6% and 12.8%, respectively. Paralytic disease was observed in 3.8%, and cranial nerve injury in 5.3% of the TBE patients. Permanent CNS dysfunction after 1 year was found in 30.8% of patients; in 8.5% of all TBE cases, severe disabilities required adjustment of daily activities. Cognitive CNS dysfunction was the dominant symptom in patients with more pronounced sequelae. A higher risk for incomplete recovery was seen for the encephalitic form of TBE (odds ratio (OR), 4.066; 95% confidence interval (CI), 1.848–8.947). Papers II and III: A prospectively collected material from patients with TBE (n=129), aseptic meningoencephalitis of non-TBEV aetiology (n=79) and healthy TBEV-naive Lithuanians (n=135) were used in studies on chemokine receptor 5 (CCR5) and Toll-like receptor 3 (TLR3) rs3775291 gene polymorphisms. In addition, children TBE cohort (n=117) and a cohort of adults with severe TBE (n=103) were recruited in Paper III. The prevalence of CCR5Δ32 homozygotes was higher among the adults with TBE (2.3%), among children with TBE (2.5%), among adults with severe TBE (1.9%), and in the overall cohort of TBE patients (2.3%) than in controls (0%) (p<0.05). Hence, the CCR5 polymorphism was identified as a significant risk factor for clinical TBE. The CCR5Δ32 allele prevalence was higher in the combined children and adult TBE cohort compared with TBEV-naive individuals, and suggested CCR5Δ32 allele being a risk factor for clinical TBEV infection (OR 1.672; 95% CI 1.005–2.782). The nonfunctional homozygous TLR3 genotype was less prevalent among the combined TBE cohort (11.5%) than among controls (19.9%) (p = 0.025), but did not differ between children TBE and controls. The genotype and allele prevalence of CCR5 and TLR3 did not differ in children nor adult TBE cohorts stratified by disease severity. In adults with severe TBE, homozygous functional TLR3 genotype and wt allele were less prevalent than in adults with the whole disease severity spectrum (44.4% vs 59.8% p = 0.022 and 65.2% vs 76.4% p = 0.009; respectively). Paper IV has shown that cerebrospinal fluid (CSF) KYNA levels were considerably higher in patients with TBE recruited from Paper I (5.3 nmol L-1) than in control subjects (0.99 nmol L-1) and increased (p<0.05) with severity of TBE. Conclusion: TBE is the main CNS infection in adults in Lithuania, causing a considerable morbidity with long-lasting sequelae in one-third of patients. Cognitive CNS dysfunction dominates and is the major cause of long-lasting impairment of the quality of life. High levels of KYNA in CSF of TBE patients serve as a marker of severity of TBE. Host genetic polymorphism plays a role in the development of clinical TBE and may even be linked to the disease severity

A morphological study of the effects of cycloleucine on the central and peripheral nervous systems of the mouse

Cycloleucine (CL) is a very potent inhibitor of S-adenosyl methionine transferase causing a rapid decline in CNS S-adenosyl methionine levels and increase in methionine in the nervous system. CL interrupts the transmethylation reaction in the CNS similar to that caused by deficiency of vitamin B12 or folic acid. CL was administered as a single dose intraperitoneally (2mg/g body weight) to mice of varying ages (21 days - 5 months). The 21 day old mice given CL 2mg/g body weight showed evidence of toxicity within 24 hours and thereafter developed progressive muscle weakness and ataxia. Animals did not survive longer than 1 week. Light and electron microscopic examination o f the central and peripheral nervous systems, from 12 hours to 7 days post-injection showed that intramyelinic vacuolation developed in the white matter of brain and cord within 12 hours but no myelin vacuolation occurred in peripheral nerves. Axonal lesions in the distal parts of motor nerves occurred within 1 2 - 2 4 hours resulting in degeneration of intramuscular nerve fibres and terminals. Motor end-plates became denervated. There was no degeneration of motor or sensory nerves in the muscle spindles. Later there was evidence of axonal degeneration in tibial and sciatic nerves. Many dorsal root ganglion cells became vacuolated or necrotic three days after administration of CL and numerous degenerated fibres were noted in the white matter of the spinal cord, especially in funiculus gracilis. The intramyelinic vacuolation in the white matter of brain and cord persisted and became more severe during the course of the experiment. In adult mice (6 weeks - 5 months) the pathology consisted mainly of distal motor axonal degeneration which developed at 1 - 2 days. Only slight intramyelinic vacuolation in white matter was noted. At 3 days later, numerous degenerated fibres were seen in the posterior columns of cervical cord, especially in the funiculus gracilis. In a second series of experiments valine (3 mg/g body weight) was given every 12 hours for 6 doses beginning either 24 or 48 hours after CL. Valine (VL) is a very effective antidote against cycloleucine and reversed its toxicity. The intramyelinic vacuolation disappeared from the white matter in the CNS leaving little residual pathology. Regenerating axons and remyelinated fibres were found in previously degenerated distal peripheral nerves and denervated motor end-plates. The reinnervation took place more rapidly in animals given VL from 24 hours after CL than 48 hours after CL. In conclusion it can be stated that CL causes a distal motor axonopathy and sensory ganglion cell necrosis in addition to the previously reported myelinic vacuolation in the CNS. The mechanism of toxicity of CL is likely to be related to the failure of transmethylation processes affecting particularly myelin basic protein and perhaps membrane turnover at active sites of transmitter release such as the neuromuscular junction

Photodynamic therapy of a mouse glioma

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The structure of the diencephalon in the insectivora (especially elephantulus myurus), the tupaioidea and the prosimian primates, with special reference to the evolution of the primate diencephalon.

A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, for the Degree of Doctor of Philosophy.The comparative structure of the diencephalon was investigated in the elephant shrew, the tree-shrew and several of the prosimian and anthropoid primates, including man. The brains were perfused with and fixed in formol saline. Most of those brains were sectioned transversely; others horizontally and sagitaliy. Sections of the diencophalon were stained with the cresyl-echt violet method for cytology and the study of cytoarchitectonics, and with the Kluver and Barrera, and Simmons techniques for myeloarchitectonics.WHSLYP201