Michael A. Williams

Effect of gravity and microgravity on intracranial pressure

Astronauts have recently been discovered to have impaired vision, with a presentation that resembles syndromes of elevated intracranial pressure on Earth. Gravity has a profound effect on fluid distribution and pressure within the human circulation. In contrast to prevailing theory, we observed that microgravity reduces central venous and intracranial pressure. This being said, intracranial pressure is not reduced to the levels observed in the 90 deg seated upright posture on Earth. Thus, over 24 h in zero gravity, pressure in the brain is slightly above that observed on Earth, which may explain remodelling of the eye in astronauts.

Lower body negative pressure to safely reduce intracranial pressure

During long‐term missions, some astronauts experience structural and functional changes of the eyes and brain which resemble signs/symptoms experienced by patients with intracranial hypertension. Weightlessness prevents the normal cerebral volume and pressure ‘unloading’ associated with upright postures on Earth, which may be part of the cerebral and ocular pathophysiology. By placing the lower body in a negative pressure device (LBNP) that pulls fluid away from cranial compartments, we simulated effects of gravity and significantly lowered pressure within the brain parenchyma and ventricle compartments. Application of incremental LBNP demonstrated a non‐linear dose–response curve, suggesting 20 mmHg LBNP as the optimal level for reducing pressure in the brain without impairing cerebral perfusion pressure. This non‐invasive method of reducing pressure in the brain holds potential as a countermeasure in space as well as having treatment potential for patients on Earth with traumatic brain injury or other pathology leading to intracranial hypertension.

Hydrocephalus in the Elderly: Surgical Management of Idiopathic Normal Pressure Hydrocephalus

Idiopathic normal pressure hydrocephalus (iNPH) was first described by Dr. Salomon Hakim in 1964 as a clinical triad of gait disturbance, cognitive difficulties, and urinary incontinence, associated with abnormal ventricular dilatation, despite normal cerebrospinal fluid (CSF) pressures. In the 1960s, Dr. Hakim and his colleagues demonstrated the effectiveness of CSF diversion surgery (shunting) for patients with iNPH, which to date has remained the only recommended modality of treatment for the disease. This chapter will also briefly review the issues associated with the limited role for endoscopic third ventriculostomy (ETV) and pharmacologic agents (drugs) in the treatment of patients with iNPH.

Hydrocephalus in the Elderly: Diagnosis of Idiopathic Normal Pressure Hydrocephalus

Idiopathic normal pressure hydrocephalus (iNPH) is a neurological disorder of the elderly characterized by gait impairment, urinary urgency or incontinence, and dementia in association with enlargement of the cerebral ventricles secondary to impaired circulation of cerebrospinal fluid (CSF), first described by Salomon Hakim in 1965. The only effective treatment of iNPH is CSF diversion with shunt surgery.

Book Review: Gnosis and Faith in Early Christianity: An Introduction to GnosticismGnosis and Faith in Early Christianity: An Introduction to GnosticismbyRoukemaRiemer. Translated byBowdenJohn. Trinity Press International, Harrisburg, 1999. 212 pp.

He is portrayed as the first bishop of Jerusalem. Part III deals with James and Jewish Christianity. James is portrayed in terms of the Jewish tradition of the righteous sufferer. The letter of James is an attempt to relate the tradition of early Jewish Christianity to the situation of exiles after the fall of Jerusalem. The letter preserves an early tradition of Jesus teaching, and it opposes a distortion of Pauls view of justification and works righteousness. A brief excursus offers a critique of Robert Eisenmanns book James the Brother of Jesus, which Painter describes as both erudite and eccentric (p. 277). Painter has revised the role of James; in most respects it is a modest and welcome revision. He deals carefully with both the original sources and with the growing amount of secondary material. The volume edited by Chilton and Evans is an excellent contribution to that secondary material. It is based on several international meetings and a consultation at Bard College in 1997. Chilton provides an introduction as well as some conclusions and questions, particularly about the role of the Nazirite vow. The assumption is that James and earliest Christianity must be understood in relationship to Temple Judaism. Eight well-known scholars explore various aspects of this perspective. Issues of background and context deal with Qumran, Palestinian traditions, halakah, and purity. Other papers deal with James and Jewish Christianity: his relationship to Paul, his role in the conflict in Antioch, the reasons for his death, and the deaths of Jesus and James as martyrs. The volume is highly useful for those who want to explore such issues in greater depth.