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Trace- and major-element zoning in garnet from a pelitic schist from NE Sardinia (Italy) was measured by ion and electron microprobe. The rock consists of porphyroblastic garnets, and a matrix made up chlorite, chloritoid, muscovite, quartz and minor staurolite and biotite. Porphyroblastic garnet contains inclusions of quartz, chloritoid, chlorite, muscovite, allanite, apatite, ilmenite and monazite. Garnet shows a zoning profile with respect to some major and trace elements. Mg and Fe gradually increases from the core to rim, whereas Ca, Mn, REE and other trace elements such as Y, Zr, Ti and V decrease. Sc has a maximum at the outer core and lowest values at the rim. The Mg, Fe garnet zoning profile was controlled by the equilibrium chloritoid + chlorite + quartz = garnet + H2O. Biotite and staurolite were formed by the reaction: garnet + chlorite + muscovite + quartz = staurolite + biotite + H2O. A significant role in the REE behaviour during garnet growth was played by the newly-formed accessory phase monazite.

Recent studies in adult animals have shown that even small decreases in brain or core temperature ameliorate the damage resulting from hypoxic-ischemic insults. To determine the effect of minor reductions in ambient temperature either during or after an hypoxic-ischemic insult on the brain of the immature rat, 7-d-postnatal rat pups underwent unilateral common carotid artery ligation followed by exposure to hypoxia in 8 oxygen for 3 h. Control animals were maintained at 37°C during hypoxia-ischemia. Intraischemic hypothermia was induced during the insult at temperatures of 34°C and 31°C. Postischemic hypothermia was induced by exposing rat pups that underwent hypoxia at 37°C to recovering environments of 34°C and 31°C. Temperatures were recorded every 15 min from thermistor probes placed in the ipsilateral hemisphere and rectally. Neuropathologic alterations were assessed at 30 postnatal d. During hypoxia, animals became poikilothermic. Brain damage occurred in 90 of rat pups exposed to hypoxia-ischemia at 37°C. Cerebral injury significantly decreased with decreasing temperatures during hypoxia-ischemia (p < 0.01). Only 30 of rats had brain damage when exposed to hypoxia-ischemia at 34°C, and none of the rats exposed at 31°C had brain damage. In contrast, there was no difference in the extent of cerebral injury between rat pups recovered under hypothermic conditions of either 34°C or 31°C compared with those recovered at 37°C. The results indicate that reductions in temperature of 3 to 6°C have a protective effect during but not immediately after hypoxia-ischemia. These findings have important implications about the thermoregulatory control of the sick newborn infant.

The power launching into multimode optical fibers with any profile of refractive index is analyzed by means of the geometrical optics. First two formulas of the numerical aperture are obtained, one including and the other excluding the contribution of leaky skew rays. Each one of these two numerical apertures has a certain domain of application, and the launching efficiencies from incoherent sources into optical fibers are calculated in both cases. Useful formulas and plots of launching efficiency for a few refractive index profiles are given. Finally the power losses due to source-fiber coupling errors (separation, displacement, or misalignment) are evaluated, and an interesting effect of virtual lengthening of the fiber is found.

ABSTRACT: Recent studies in adult animals have shown that even small decreases in brain or core temperature ameliorate the damage resulting from hypoxic-ischemic insults. To determine the effect of minor reductions in ambient temperature either during or after an hypoxic-ischemic insult on the brain of the immature rat, 7-d-postnatal rat pups underwent unilateral common carotid artery ligation followed by exposure to hypoxia in 8% oxygen for 3 h. Control animals were maintained at 37°C during hypoxia-ischemia. Intraischemic hypothermia was induced during the insult at temperatures of 34°C and 31°C. Postischemic hypothermia was induced by exposing rat pups that underwent hypoxia at 37°C to recovering environments of 34°C and 31°C. Temperatures were recorded every 15 min from thermistor probes placed in the ipsilateral hemisphere and rectally. Neuropathologic alterations were assessed at 30 postnatal d. During hypoxia, animals became poikilothermic. Brain damage occurred in 90% of rat pups exposed to hypoxia-ischemia at 37°C. Cerebral injury significantly decreased with decreasing temperatures during hypoxia-ischemia (p < 0.01). Only 30% of rats had brain damage when exposed to hypoxia-ischemia at 34°C, and none of the rats exposed at 31°C had brain damage. In contrast, there was no difference in the extent of cerebral injury between rat pups recovered under hypothermic conditions of either 34°C or 31°C compared with those recovered at 37°C. The results indicate that reductions in temperature of 3 to 6°C have a protective effect during but not immediately after hypoxia-ischemia. These findings have important implications about the thermoregulatory control of the sick newborn infant.

A model of hypothermic circulatory arrest with recovery has been developed in the newborn dog. Eleven puppies were anesthetized with halothane, paralyzed and artificially ventilated with 70% nitrous oxide -30% oxygen to paO2>60 mm Hg, paCO2=33–42 mm Hg and pHa=7.35–7.42. Animals were surface cooled to 20°C, following which cardiac arrest was effected with i.v. KCl. Dogs remained asystolic without ventilation for 1.0, 1.5 or 1.75. Resuscitation was accomplished with closed-chest compression, mechanical ventilation, i.v. epinephrine and NaHCO3, and rewarming to 37°C. Thereafter, the puppies were allowed to recover from anesthesia and maintained for either 18–22 h (n=9) or 72 h (n=2), at which time they underwent perfusion-fixation of their brains for pathologic analysis. Of the total, four out of four puppies arrested for 1.0 h exhibited no brain damage, including one recovered for 72 h; whereas one out of three and four out of four puppies arrested for 1.5 and 1.75 h, respectively, showed brain damage predominantly of the cerebral cortex but also of the basal ganglia and amygdaloid nucleus. The hippocampus was spared, even in a 1.75-h-arrested animal which was maintained for 72 h. No differences in pre- or post-arrest systemic blood pressure, heart rate, or acid-base balance were observed between the brain damaged and undamaged animals except for the single damaged animal arrested for 1.5 h, for which the blood pressure prior to cardiac arrest and during recovery was the lowest of all survivors. We conclude that newborn dogs undergoing hypothermic circulatory arrest for 1.0–1.5 h and which are fully recoverable without systemic hypotension exhibit no brain damage, whereas puppies arrested for 1.75 h exhibit brain damage entirely on the basis of global cerebral ischemia arising during the cardiac arrest. The experimental model has relevance to newborn human infants undergoing hypothermic circulatory arrest for the operative correction of congenital heart defects and should be useful for studying mechanisms of cellular injury in brain and other organs during prolonged ischemia.

This study was undertaken to determine: (a) the duration of hypoxia required to produce brain damage in immature rats with unilateral carotid artery ligation (Levine technique); (b) the regions of immature brain most vulnerable to hypoxia-ischemia (HI); and (c) the neuropathology of the remote HI insult. To this end, 7-day postnatal rats, subjected to unilateral carotid artery ligation combined with hypoxia of varying durations (45, 60, 75 or 90 min), were killed at 30 days of postnatal age and their brains examined by light microscopy. The results indicated that a longer duration of HI was more likely to produce brain lesions and that the extent and severity of the lesions closely correlated with the length of HI. Shorter intervals of HI primarily damaged the cerebral cortex and hippocampus, while longer periods resulted in more extensive damage and were often associated with cavitary lesions of the cerebral hemisphere. Comparison of HI brain damage produced by the Levine technique in immature and adult rats suggested that in immature rats: (a) the cavitary lesions were common; (b) the non-cavitary cortical lesions had a tendency to show a vertical band-like distribution — a pattern never seen in adults; and (c) the lesions often showed mineralization. The similarities between these experimentally produced HI cerebral lesions and those observed in the developing human brain, such as ulegyria and porencephaly, are discussed.

Abstract: The paper describes a destructive neutron activation procedure for the determination of all platinum group elements (PGE). Only a few steps are required after irradiation, namely sample dissolution, osmium and ruthenium separation by solvent extraction, anion exchange separation of remaining noble metals and counting. The chemical yield is evaluated. The method has been used for the determination of noble metals in a large variety of standard reference materials, mainly of geological and technological origin. The results, given as the average of four independent analyses are reported and discussed. Average precision for the whole procedure is usually below 8% and sensitivities are adequate to meet the analysis requirements of terrestrial PGE- and Au-poor materials.

Abstract: An updata REE measurement of gabbro GOG-1 was carried out by means of neutron activation analysis (NAA). The availability of high amounts of rock powder allowed the sample to be well ground and homogenized before analysis. Homogeneity tests, carried out on different aliquots, show that GOG-1 samples can be considered homogeneous when over 50 mg aliquots of rock powder are employed for analytical work. Results from ICP-AES and SIMS investigations of REE in gabbro GOG-1 are in quite good agreement with NAA data and support the possibility of employing GOG-1 rock samples as reference material for geoanalysis.

Abstract: The geochemical behavior of REE has been tested in the Umbro-Marchean (Italy) pelagic sequences of Cretaceous-Paleocene age. REE were determined by INAA in a number of limestone, marl and clay samples. Both chondrite and shale normalized patterns are discussed: the observed REE amounts and distributions are mainly attributed to highly complex diagenetic processes.

Abstract:  Mantle peridotites of the Internal Liguride (IL) units (Northern Apennines) constitute a rare example of the depleted lithosphere of the Jurassic Ligurian Tethys. Detailed chemical (ICP-MS and SIMS techniques) and isotopic investigations on very fresh samples have been performed with the major aim to constrain the timing and mechanism of their evolution and to furnish new data for the geodynamic interpretation. The data are also useful to discuss some general geochemical aspects of oceanic-type mantle. The studied samples consist of clinopyroxene-poor spinel lherzolites, showing incipient re-equilibration in the plagioclase-facies stability field. The spinel-facies assemblage records high (asthenospheric) equilibration temperatures (1150–1250° C). Whole rocks, and constituent clinopyroxenes, show a decoupling between severe depletion in highly incompatible elements [light rare earth elements (LREE), Sr, Zr, Na, Ti] and less pronounced depletion in moderate incompatible elements (Ca, Al, Sc, V). Bulk rocks also display a relatively strong M(middle)REE/H(heavy)REE fractionation. These compositional features indicate low-degree (<10%) fractional melting, which presumably started in the garnet stability field, as the most suitable depletion mechanism. In this respect, the IL ultramafics show strong similarity to abyssal peridotites. The Sr and Nd isotopic compositions, determined on carefully handpicked clinopyroxene separates, indicate an extremely depleted signature (87Sr/86Sr=0.702203–0.702285; 143Nd/144Nd=0.513619–0.513775). The Sm/Nd model ages suggest that the IL peridotites melted most likely during Permian times. They could record, therefore, the early upwelling and melting of mid ocean ridge basalt (MORB) type asthenosphere, in response to the onset of extensional mechanisms which led to the opening of the Western Tethys. They subsequently cooled and experienced a composite subsolidus evolution testified by multiple episodes of gabbroic intrusions and HT-LP retrograde metamorphic re-equilibration, prior to their emplacement on the sea floor. The trace element chemistry of IL peridotites also provides useful information about the composition of oceanic-type mantle. The most important feature concerns the occurrence of Sr and Zr negative anomalies (relative to “adjacent” REE) in both clinopyroxenes and bulk rocks. We suggest that such anomalies reflect changes in the relative magnitude of Sr, Zr and REE partition coefficients, depending on the specific melting conditions.

In this paper the different loss mechanisms of light in multimode fibres are analysed from the point of view of the extinction of leaky skew rays. First, the intrinsic loss mechanism of leaky rays due to optical tunnel effect is fully investigated by means of a quasi-classical approach and a well approximated form of the relative extinction coefficient is derived. Second, the influence of other loss phenomena, due to imperfections or impurities in the fibre such as core and cladding absorption and scattering, on the relative contribution of leaky rays is analysed. Finally some phenomena of failed excitation of leaky rays are also examined. The phenomena are analysed both qualitatively and quantitatively and a comparative analysis of various effects referring to actual fibres is made.

Neuropathologic findings in an infant with congenital right facial and bilateral lateral recturs palsy (Möbius syndrome) are presented. Multiple microscopic foci of necrosis were found in the lower pontine tegmentum, involving the region of the intramedullary course of 6th and 7th cranial nerves. The significance of pathologic findings in this infant and 14 additional published cases of Möbius syndrome is discussed.

Abstract: The conservation law of radiance as a suitable tool for investigation of radiation transfer processes between two systems is treated. Original proofs of this law are given and its deep thermodynamical foundation is pointed out. Finally, applications to general problems of power coupling and particularly to the radiation transfer from incoherent sources (LED) into multimode optical fibres are carried out.

In this paper the geometrical theory of pulse distortion and energy launching into multimode optical fibres is generalized when skew rays are taken into account.

Petrographic, textural and chemical investigations on the Zabargad Island ultramafic association of peridotites and pyroxenite layers allow the main stages of their evolution to be identified. The whole evolution was characterized by three main stages, attributed to different geodynamic situations.

Ion probe investigations on mineral phases forming the Al-Di pyroxenites from the Zabargad peridotite body indicate that porphyroclastic pyroxenes in composite mafic layers record an unusual HREE, Zr, Sc enrichment not registered by pyroxenes in spinel websterites. Orthopyroxene in the opx+sp clusters forming the inner, cpx-free zone of layered pyroxenites shows strongly fractionated REE patterns (HREEN/LREEN>1000; Yb>100xch) and very high Zr, Sc and Y abundances (up to 30,672 and 60ppm, respectively). In the outer, cpx-rich zone porphyroclastic clinopyroxene is strongly HREE enriched (HREEN/LREEN~29; Yb~ 269xch) and displays very high Sc and Zr abundances (up to 819 and 164 ppm, respectively). It is suggested that the unusual trace element abundances are inherited from a precursor garnet. Composite pyroxenite layers are interpreted as former garnet clinopyroxenites characterized by gnt/cpx modal zoning. The sp+opx(cpx-free) assemblage in the inner part is a product of the break-down reaction of garnet upon decompression, with Ca of the original garnet completely entering the enstatite solid solution. The temperature at which the breakdown reaction occurred is estimated to be higher than 1000°C (P in the range 20–30 kbar). In the outer part, decompression caused the garnet to form a sp+opx assemblage; however, the grossularite component participated in the formation of new clinopyroxene which reacted with the clinopyroxene present in the original mode before the decompression reaction, thus forming a cpx2+sp+opx assemblage. As a result of garnet breakdown, pyroxenes have peculiar HFSE anomalies. Progressive upwelling during the Red Sea rifting produced incomplete reaction under pl-facies conditions. The geochemical signatures of precursor garnet in pyroxenes were partially crased during the recrystallization from granular spincl-bearing to granoblastic plagioclase-bearing assemblages, being preserved only in a few porphyroclast relies. The finding of pyroxenes with trace element characteristics of precursor garnet has important geodynamic and geochemical implications. Al-Di pyroxenite layers had a long history within the mantle, before the continental lithosphere rifting and thinning took place in the region. It is suggested that Al-Di pyroxenites were formed by deep-seated tholeiitic magmatism unrelated to the Red Sea evolution, thus representing the earliest event in the Zabargad upper mantle. Garnet breakdown significantly preceded the metasomatism induced by hydrous fluids (crystallization of Ti-rich pargasite) and the later intrusion of hydrous (Cr-Di) pyroxenite dykes. During the stages of mantle evolution, the HFSE anomalies in pyroxenes varied significantly. We note that the study of HFSE anomalies in mineral phases reveals complex geochemical histories which are not recorded by the whole-rock system.

Mantle peridotites of the External Liguride (EL) Units (Northern Apennines) mainly consist of fertile spinel-lherzolites partially recrystallized to plagioclase-facies assemblages, and are consequently appropriate to investigate the interphase element partitioning related to the transition from spinel- to plagioclase-facies stability field. Evidence for the development of the plagioclase-facies assemblage is mainly given by: (1) large exsolution lamellae of orthopyroxene and plagioclase within spinel-facies clinopyroxene; (2) plagioclase rims around spinel; (3) granoblastic domains made up of olivine+plagioclase±clino-and orthopyroxene. In situ major and trace [REE (rare-earth elements), Ti, Sc, V, Cr, Sr, Y, Zr and Ba] element mineral analyses have been performed, by electron and ion probe, on selected samples which show the progressive development of the plagioclase-bearing assemblage. The main compositional variations observed during the change from spinel- to plagioclase-facies minerals are as follows: (1) clinopyroxenes decrease in Al, Na, Sr, Eu/Eu* and increase in Y, V, Sc, Cr, Zr and Ti; (2) amphiboles decrease in Eu/Eu*, Sr, Ba and increase in Zr and V; (3) spinels decrease in Al and increase in Cr and Ti. The most striking feature is the decoupling in the behaviour of similarly incompatible elements (D about 0.1) in clinopyroxene, e.g. Sr decrease is mirrored by Zr increase. Massbalance calculations indicate that the trace element interphase redistribution documented in the EL peridotites occurred in a closed system and in response to the metamorphic reaction governing the transition from the spinel- to the plagioclase-facies stability field. The observed element partitioning reveals, moreover, that subsolidus re-equilibration processes in the upper mantle produce HFSE (high-field-strength element)/REE fractionation in minerals, which must be evaluated for a reliable determination of mineral-melt distribution coefficients. The results of this study furnish evidence for subsolidus metamorphic evolution during decompression, without concomitant partial melting processes. This is consistent with the interpretation that the EL peridotites represent subcontinental lithospheric mantle emplaced at the surface in response to lithospheric thinning and tectonic denudation mechanisms related to the Triassic-Jurassic rifting of the Ligure-Piedmontese basin.

Ion microprobe data (REE, Na, Sc, Ti, V, Cr, Sr, Zr) of unaltered clinopyroxenes in the ophiolitic basalts from the Northern Apennines have been used in a epx-based geochemical modelling of MORB magmatism from both External (EL) and Internal (IL) sectors of the Ligurian Tethys (i.e. Jurassic Ligure-Piemontese basin), alternative to the more common whole-rock approach. Clinopyroxenes from EL basalts display slightly fractionated LREE (CeN/SmN~0.5) and HREE (GdN/ YbN~1.5) patterns and large variations in the REE composition (up to 6 times from microphenocryst cores to interstitial clinopyroxenes). Interstitial clinopyroxenes in IL basalts are similar to the microphenocrysts from the most primitive EL basalts. By contrast, IL microphenocrysts are characterized by greater LREE (CeN/SmN ~0.3) and lesser HREE (GdN/YbN<1.2) fractionation. The comparison of trace element variations in wholerocks and clinopyroxenes clearly shows that the olivine and plagioclase portion of the fractionation sequence is poorly represented by the EL and IL basalts. In fact, ophiolitic basalts mainly consist of a minor interstitial glass (now deeply altered) associated with a prevailing plagioclase-clinopyroxene assemblage crystallized from liquids significantly evolved along the olivine-plagioclase-clinopyroxene saturation boundary. Thus, bulk rock chemistry is largely governed by clinopyroxene composition. This, in addition to alteration, indicates that the bulk rock chemistry does not provide reliable chemical information to constrain the composition and the generation of the parental magmas. Unfortunately, most clinopyroxenes are characterized by complex zoning, probably caused by disequilibrium partitioning during crystal growth as a result of kinetic factors. On this ground, estimation of melt chemistry and inferences about the origins of these basalts are only allowed by the core compositions of microphenocrystic clinopyroxenes. Modelling of (Nd/Yb)N and Ti/Zr in the parental magmas, as deduced from the clinopyroxene compositions, indicates thata EL and IL basalts do not represent products of different mantle source composition. Rather, they were generated by varying degrees of fractional melting in the spinel stability field, lower for the EL (a few percent) relative to IL, totalling no more than 10% of an asthenospheric MORB source, and leaving in the residua clinopyroxene with REE patterns similar to those shown by IL suboceanic type peridotites. Accordingly, these latter are interpreted as refractory residua after MORB-generating fractional melting occurred during rifting and opening of the Ligure-Piemontese basin. By contrast, residual clinopyroxenes from the EL subcontinental type peridotites are not consistent with low degrees of fractional melting in agreement with the current interpretation that EL peridotites are unrelated to the MORB magmatism in the Ligure-Piemontese basin and represent lithospheric mantle material already emplaced towards the surface by a tectonic denudation mechanism during the early stages of oceanic rifting.

Summary Ultramafic xenoliths from the basaltic tuff of Kapfenstein (Graz Basin) are mainly protogranular and protogranular- to- porphyroclastic spinel lherzolites. In addition to these common rocks, a coarse-grained spinel harzburgite and a heterogeneous spinel peridotite consisting of a clinopyroxene-poor harzburgite and a clinopyroxene-rich lherzolite have been found. Interstitial amphiboles (pargasite and kaersutite) are present in most xenoliths. The magmatic activity which brought these xenoliths to the surface is part of the Plio-Pleistocene extension-related alkali basalt volcanism which took place in the Carpatho-Pannonian Region, post-dating the subduction-related calc-alkaline volcanism which formed the Inner Carpathian arc.

Previous investigations from our laboratory have shown that hyperglycemia during the course of hypoxia-ischemia (H-I) does not increase brain damage in immature animals as occurs in adults (Voorhies et al 1982). To clarify biochemical mechanisms responsible for this age specific paradox, we subjected 7-day postnatal rats to unilateral common carotid artery ligation followed by the hypoxia produced by the inhalation of 8% oxygen for 2hr (Rice et al, 1981). Experimental animals received 0.1 ml. 50% glucose sc 15 min prior to onset of hypoxia, which increased blood glucose to 350 mg/dl for 2 hr. Glucose in the cerebral hemisphere ipsilateral to the carotid occlusion was exhausted by 20 min of H-I in control (saline injected) rats but not until 2 hr in glucosetreated animals. Brain lactate and puruvate increased to a greater extent in the glucose-treated animals but only at 20 and 60 min, such that L/P ratios were comparable at 2 hr. Declines in ATP and P-creatine occurred earlier in control animals, but by 2 hr low levels were seen in both groups. Total adenine nucleotides also were depleted to the same degree. The findings indicate that despite an early protective influence of glucose on brain glycolytic intermediates & high energy reserves during cerebral H-I, the effect is short lived even with continuing hyperglycemia. Limited glucose entry into the immature brain at any blood glucose level retards anaerobic metabolism during H-I; which, in turn, leads to a disruption of the energy state of the tissue and ultimate brain damage. (NIH #HD-15738).

Cerebral metabolic responses to status epilepticus (SE) were investigated for the first time in neonatal primates. Ten 14-day old Marmoset monkeys were anesthetized with ketamine & monitored for systemic BP, blood gases & glucose. An IM injection of bicuculline produced tonic-clonic convulsions without hypoxemia, hypoglycemia or hypotension for 30 min,; thereafter, brains were quick frozen & prepared for regional NADH reflectance fluorometry & ATP bioluminescence. Micro-samples of forebrain were analyzed for ATP (C-2.66, SE-2.04), P-creatine (C-3.45, SE-0.92), Glucose (C-3.57, SE-0.20) and Lactate (C-1.23, SE-10.05)mmol/kg. Similar alterations in metabolite levels were noted in diencephalon and in deep cerebral cortical structures. NADH fluorometry produced patchy relatively symmetrical areas of enhanced fluorescence in boundary zones between anterior & middle cerebral arteries of cerebral cortex, in cingulate gyri & diencephalon. Regional ATP was decreased globally in SE animals. Furthermore, ATP levels were not statistically different in brain regions with high or low NADH fluorescence. Thus, glycolytic intermediates & high energy reserves are disrupted in brains of neonatal Marmosets sustaining SE. The insult follows in part a vascular distribution. Whether or not the altered energy state is severe enough to be associated with brain damage is under investigation. (Supported by Research Service of the Veterans Administration and by NIH #PNS-13515 and #HD-15738.

Previous investigations from our NICU have shown that term infants severely asphyxiated at birth often sustain saggital sinus thrombosis with secondary hemorrhagic infarction of the brain. In these term infants, the thrombotic obstruction to venous outflow was documented by digital IV angiography (voorhies, et al, 1984). Recently, a 30-week gestation infant was born to a 32 year old Black female with severe sickle-thalassemia. The infant was delivered by emergency c-section for fetal bradycardia. B.W. was 1.060 gm & Apgar scores were 2 & 6. The infant required immediate intubation s subsequent ventilation. Neurological exam revealed a stuperous, flaccid newborn infant with preservation of brainstem and deep tendon reflexes. Seizures were never observed. Head ultrasound & CT scan at 8 hr revealed large, bi-occipital hemorrhagic infarcts. Germinal matrix hemorrhages were also present but there was no IVH. The saggital sinus was incompletely filled with blood at its posterior aspect, and a Delta sign was present. The CT findings in this infant are equivalent to those observed in term asphyxiated infants in whom saggital sinus thrombosis occurred. Sequential sonograms showed evolving cystic encephalomalacia of the occipital lobes; repeat CT scan at 1 mo showed large bilateral porencephalic cysts, presently (2 mo) the infant remains lethargic with little or no spontaneous movements. It is likely that saggital sinus thrombosis occurred as a consequence of multiple factors; including prematurity, birth asphyxia anemia, congestive heart failure and viral disease. The hemorrhagic infarcts, resulting from the saggital sinus thrombosis produced major and permanent cystic brain damage.

Resistance to anoxia is characteristic of developing nervous tissue, and is most pronounced in the fetus. Whether this tolerance resides in differences in structural-functional maturity or in metabolic factors i.e. “resting” levels of cerebral energy reserves, rates of energy utilization, or glycolytic capacity is unresolved. Fetal rats at term, delivered by maternal decapitation and hysterotomy, survive in N2, at 37°C (LD85=50 min) twice as long as 1-day (1D) and 5 times as long as 7-day (7D) postnatal rats. Total energy reserves in quick-frozen forebrains [˜P=2(ATP)+ADP+P-creatine+2(glucose)+2.9 (glycogen)] of fetuses (27.0 mM/Kg) were 11% and 13% higher than in 1D and 7D rats, owing chiefly to differences in glycogen. Following decapitation, lactate accumulated in fetal and 1D brain in linear fashion up to 5 min (maximal glycolytic flux), but at a greater rate in fetuses (0.97 vs 0.69 mM/Kg/ min). In 7D rats maximal lactate production (1.94 mM/Kg/min) occurred from 1-2 min, following a lag. From the changes in preformed and potential cerebral energy stores during ischemia initial rates of energy consumption (metabolic rate) were obtained (Lowry et al, 1964). In fetal and 1D rats, energy consumption was linear for 5 min with slopes of 1.57 and 1.33 mM ˜;P/Kg/min, respectively. In 7D rats energy use was linear for only 2 min and about twice as fast (2.58). Thus, in postnatal (1D and 7D) rats anoxic survival and cerebral energy consumption were inversely related; no such correlation was observed for fetal animals. (Supported by NIH #NS-03346)

Ligation of the uterine arteries during late gestation leads to retarded somatic growth and compromised cerebral development in experimental animals (Wigglesworth, 1964). The pathogenesis of the altered brain growth may stem from chronic tissue hypoxia and/or substrate deficiency. Pregnant rata of 17 days gestation were subjected to laparotomy, following which the uterine artery supplying one uterine horn was ligated. The opposite horn and its blood supply were left undisturbed, its fetuses serving as controls. Dams were sacrificed at term by decapitation & fetuses delivered by C-section. Fetal brains were removed & analyzed. Animals from the ligated horn exhibited decreased body (-25%) & brain (-10%) weights compared to controls. Brain dry weight was also lower (-7.4%), but lipid content was not different. Oxidative metabolites & high-energy reserves (mM/kg w.w.) were:The absence of significant differences in brain metabolites between control & experimental groups reflects adequate oxygenation of, & glucose delivery to, the brains of the growth retarded fetuses. Thus, a deficiency of substrates other than glucose appears to be the critical factor in the cerebral under development of experimental intra-uterine growth retardation.