Connection between the membrane electron transport system and Hyn hydrogenase in the purple sulfur bacterium, Thiocapsa roseopersicina BBS.

Thiocapsa. roseopersicina BBS has four active [NiFe] hydrogenases, providing an excellent opportunity to examine their metabolic linkages to the cellular redox processes. Hyn is a periplasmic membrane-associated hydrogenase harboring two additional electron transfer subunits: Isp1 is a transmembrane protein, while Isp2 is located on the cytoplasmic side of the membrane. In this work, the connection of HynSL to various electron transport pathways is studied. During photoautotrophic growth, electrons, generated from the oxidation of thiosulfate and sulfur, are donated to the photosynthetic electron transport chain via cytochromes. Electrons formed from thiosulfate and sulfur oxidation might also be also used for Hyn-dependent hydrogen evolution which was shown to be light and proton motive force driven. Hyn-linked hydrogen uptake can be promoted by both sulfur and nitrate. The electron flow from/to HynSL requires the presence of Isp2 in both directions. Hydrogenase-linked sulfur reduction could be inhibited by a QB site competitive inhibitor, terbutryne, suggesting a redox coupling between the Hyn hydrogenase and the photosynthetic electron transport chain. Based on these findings, redox linkages of Hyn hydrogenase are modeled.

Fatal automobile crash caused by cerebral toxoplasmosis.

An unusual case of cerebral toxoplasmosis leading to a fatal vehicular crash is presented. Massive intracerebral hemorrhage, a rare complication of cerebral toxoplasmosis in persons with acquired immunodeficiency syndrome (AIDS), caused sudden onset of increased intracranial pressure that led to loss of control of the vehicle and an ensuing fatal traffic crash.

Invasive pituitary adenoma coexisting with infiltrating temporal lobe glioma.

We have reported the case of a young man who had the uncommon coexistence of two relatively common intracranial tumors--a pituitary adenoma and a temporal lobe glioma. The pituitary adenoma invaded nerve bundles in the left cavernous sinus, but did not extend into the left temporal lobe, where an anatomically separate oligoastrocytoma was diagnosed at autopsy. Preoperative magnetic resonance imaging may assist in the diagnosis of this and similar uncommon conditions.

Prolonged survival without neurologic deficit following traumatic dorsolateral brainstem injury.

A 25-year-old white male survived a closed head injury with brainstem damage for two years without major neurologic deficits and succumbed to an unrelated condition. Gross and microscopic study of quantity and distribution of his lesions suggest that one-sided lateral brainstem injury of traumatic nature may be compatible with long survival and only minor neurologic deficit. Future cases should be evaluated for the validity of this hypothesis.

Fungal cerebritis from intravenous drug abuse.

Three intravenous drug abusers (predominantly cocaine) developed a fulminant fungal cerebritis without any other identifiable predisposing factor. Two died and one survived with a severe neurologic deficit. Zygomycetes (nonseptated fungi) were identified in the brain tissue of two victims and Acremonium alabamensis was cultured from the brain tissue of the third. Fulminant fungal cerebritis in intravenous drug abusers (in the absence of any predisposing illness) may represent a unique variant of the acquired immunodeficiency syndrome (AIDS). Future surviving patients should be evaluated for the possibility of a cellular immune deficiency state in order to confirm this impression.

Activity of the renin-angiotensin-aldosterone system in full-term newborn infants during the first week of life.

A study was performed in 7 healthy full-term newborn infants with mean birth weight of 3130 g (range, 2650-2850 g) and a mean gestational age of 38.8 weeks (range, 37-41 weeks) to investigate the postnatal changes of plasma renin activity (PRA), plasma aldosterone concentration (PA) and urinary aldosterone excretion (UAE) in relation to electrolyte balance. PRA, PA and UAE fell significantly from their initially high values of 28.36 +/- 3.6 ng/ml/hr 1.5 +/- 3 ng/ml and 7.1 +/- 1.9 microgram/day on the first day to 6.84 +/- 2.9 ng/ml/hr (p less than 0.01), 0.71 +/- 0.1 ng/ml (p less than 0.01) and 5.5 +/- 1.6 microgram/day (p less than 0.05), respectively, on the 5th day. No significant correlation was found between either PRA and PA or PA and UAE. PRA and UAE showed a significant negative correlation with dietary sodium intake, the other parameters of sodium and potassium homeostasis, however, had no apparent influence on the activity of RAAS. The initial high level and the rapid postnatal decline in RAAS activity has been attributed to perinatal stress imposed by labour and delivery and not to the changes in sodium or potassium balance in the early days of life.

Metastatic carcinoma in meningioma.

A case of adenocarcinoma of the lung metastatic to two of three parasagittal meningiomas is presented. This is the tenth reported case of carcinoma metastatic to a meningioma.