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Objective: Meniscal injury is a common prelude to post-traumatic osteoarthritis (PTOA). Joint nerves can become damaged in arthritic joints leading to the manifestation of neuropathic pain. Both PTOA and neuropathic pain are more common in females; however, it is unknown whether the neural processing of joint pain is sex-specific., Design: Male and female Wistar rats (230-286g) underwent unilateral medial meniscus transection (MMT) and allowed to recover for 28 days. Pain development was assessed over the time course by von Frey hair algesiometry and dynamic weight bearing. Recordings from joint primary afferents was carried out by electrophysiology at end-stage disease. Nerve damage and β-endorphin levels were also compared between MMT and sham operated animals., Results: Male MMT rats exhibited significant pain behaviour compared to sham control. Evoked afferent firing rate was heightened in male MMT animals. Female PTOA rats did not show signs of pain behaviour on each of the test days and the neurophysiological properties of their nociceptors was not different from control. Peripheral neuropathy was observed in about 30% of axons from male MMT animals compared to 15% in females. Systemic β-endorphin levels in female PTOA rats was 91.0 ± 10.4 pg/mL and only 49.0 ± 5.0 pg/mL in males., Conclusions: Secondary allodynia and joint pain were observed in male but not female MMT rats. Joint nociceptors were sensitized in PTOA males but not in females. This lack of pain in females may be due to the absence of a peripheral neuropathy and greater endogenous opioid production., (Copyright © 2020 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.)

In a previous genome scan of 43 schizophrenia pedigrees, nonparametric linkage (NPL) scores with empirically derived pointwise P-values less than 0.01 were observed in two regions (chromosomes 2q12-13 and 10q23) and less than 0.05 in three regions (4q22-23, 9q22, and 11q21). Markers with a mean spacing of about 5 cM were typed in these regions in an expanded sample of 71 pedigrees, and NPL analyses carried out. No region produced significant genomewide evidence for linkage. On chromosome 10q, the empirical P-value remained at less than 0.01 for the entire sample (D10S168), evidence in the original 43 pedigrees was slightly increased, and a broad peak of positive results was observed. P-values less than 0.05 were observed on chromosomes 2q (D2S436) and 4q (D4S2623), but not on chromosomes 9q or 11q. It is concluded that this sample is most supportive of linkage on chromosome 10q, with less consistent support on chromosomes 2q and 4q. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:864-869, 2000., (Copyright 2000 Wiley-Liss, Inc.)

Endocrine dysfunction can be challenging to diagnose in children treated for brain tumors. Treatments are available for hormonal replacement and when necessary, hormonal suppression. Without these endocrine treatment regimens, life can be unnecessarily difficult or unpleasant. An endocrine survey can be used to screen at-risk neuro-oncology patients once or twice a year to facilitate the recognition of endocrine dysfunction. It is hoped that through the use of a routine screening program, physicians will be able to diagnose and begin treatment of endocrine problems in a time-efficient manner.

A 5-year review of 43 consecutive patients presenting to Scottish Rite Children's Medical Center with an open myelomeningocele defect was undertaken. The aim of the present study was to analyze the myelomeningocele defects, dimensions, and area to better define those factors that dictate the need for plastic surgical consultation for wound closure. Of the 43 patients identified, two were excluded because they first presented as older children; the remaining 41 all had their myelomeningoceles repaired within the first 36 hours of life. Of these, 31 underwent repair by the Neurosurgical Service, whereas for 10 patients (24.4%), the Plastic Surgery Service was asked to assist with closure. Comparison showed the mean (+/- standard deviation) area in the referred patients was 27.4 (7.6) cm2 versus 17.6 (7.9) cm2 in the patients not referred for closure (p = 0.002). A trend analysis predicting referral as a function of myelomeningocele area showed that 0 of 10 (0%) with an area of less than 15 cm2, 2 of 13 (15.4%) with an area equal to 15 to 20 cm2, 3 of 7 (42.9%) with an area of 21 to 25 cm2, and 4 of 9 (44%) with an area greater than 25 cm2 were referred (p = 0.001). Data from the interpretation of maximum myelomeningocele dimension also showed statistically significant trends in referral. Using multiple logistic regression, it was found that the odds of referral increased by a factor of 3.3 for every 1 cm increase in maximum dimension.

Objective: The purpose of this study was to report the clinical and imaging findings of seven children who developed extraaxial, intracranial hemorrhage 3-12 years after suboccipital craniectomy for neoplasia. We attempt to explain the hemorrhages based on a previously reported hypothesis of neomembrane formation associated with dural substitutes used to repair large dural defects., Materials and Methods: Clinical charts (seven patients), surgical and pathologic findings (four patients), and imaging studies (CT scans and MR images in four; CT scans, MR images, and angiograms in one; and CT scans only in two patients) were reviewed retrospectively. Hemorrhage occurred 3-12 years after suboccipital craniectomy for tumor (ependymoma in two, medulloblastoma in three, astrocytoma in one, and ganglioglioma in one). Silastic dural substitute was used to repair the surgical wound in six cases and human dural graft in one case. Hematomas were spontaneous in four and occurred after minor head trauma in three. Four patients had multiple hemorrhagic episodes., Results: CT scans and MR images showed acute extraaxial hemorrhages at the craniectomy site without contiguous residual or recurrent neoplasia in all patients. No intraaxial or intratumoral hemorrhage was detected. Findings on cerebral angiograms in one patient were normal. Four patients underwent surgical exploration of the hematoma and craniectomy site; no macroscopic source of bleeding was detected. The hematomas were not associated with recurrent tumor pathologically., Conclusion: Delayed, benign extraaxial hematomas may occur in children who have undergone craniectomy for tumors of the posterior fossa and have had dural substitute used to repair large defects. Fragile vessels associated with nonmembranes have been proposed as the source of hemorrhage.

Earlier results reported by the authors suggest that carotid endarterectomy can relieve symptoms of non-hemispheric ischemia in patients who present with hemodynamically significant carotid stenosis. Long-term follow-up of a subgroup of these patients is described. Some 61 patients with non-hemispheric ischemia who underwent carotid endarterectomy were reviewed. Indications for surgery and postoperative results (stroke, death, symptom relief) were determined by office visit or phone interview. Results in these patients were compared with those of an entire patient population who underwent endarterectomy performed by the authors. Mean (s.d.) follow-up was available for 42.3 (31.7) months. Perioperative stroke rate (4.9%), survival (85.3 and 64.9% at 3 and 5 years respectively) and stroke-free survival (77.1 and 63.4% at 3 and 5 years respectively) were not different from that entire cohort of 553 patients. During follow-up, 11 patients (18%) developed recurrent symptoms of non-hemispheric ischemia. Carotid endarterectomy is successful in providing long-term relief of symptoms of non-hemispheric ischemia in most patients with significant carotid bifurcation stenosis. Results in such patients are similar to those seen in patients with symptoms of anterior cerebral ischemia or with symptom-free stenoses.

Carotid endarterectomy is a common procedure aimed at the prevention of cerebral vascular accident. Death after carotid endarterectomy is rare (approximately 1%). Postoperative complications occur infrequently (3% to 5%). Myocardial infarction and cerebral vascular accident, two of the most serious postoperative complications, are often associated with changes in blood pressure that occur early in the postoperative period. In addition, cerebral vascular accident often results from thrombosis at the operative site, which may occur during the operation or in the early perioperative phase. Therefore intense monitoring of neurologic and hemodynamic status during the early postoperative period is advocated to control blood pressure and detect changes in neurologic condition. Traditionally, this care is provided in an intensive care unit. Current studies suggest that more than 80% of patients who undergo carotid endarterectomy do not use unique intensive care unit resources; rather, they require monitoring services, which can be safely provided in less intensive alternate settings. This article provides an overview of carotid endarterectomy. Postoperative complications and early (24-hour) perioperative management are reviewed. Alternative strategies to intensive care unit monitoring are proposed.

The majority of infants presenting with progressive hydrocephalus are now treated surgically with ventricular shunting. It is difficult to predict the eventual developmental outcome of most treated patients. This article reviews the results of surgical therapy for infantile hydrocephalus with particular attention to neurologic and intellectual outcome.

Purpose: To define the clinical and prognostic role of MR in a pediatric population with spinal cord injury., Methods: Fifteen children underwent MR 12 hours to 2 months postinjury using decoupled surface coils and ventilator support as needed. MR was correlated retrospectively with clinical, CT, and radiographic findings., Results: On MR, of seven children with spinal cord neurologic deficits, four had hemorrhagic contusions, one had nonhemorrhagic contusion, one had extensive infarction, and one revealed a normal cord. All had persistent deficits on hospital discharge. Eight without cord neurologic deficit revealed no cord lesions on MR; this group included two with epidural hematoma, four with ligamentous disruption, and two with bone compression., Conclusions: Children may have extensive cord contusion and/or infarction with minor, remote, or no fracture dislocation. Because both hemorrhagic and nonhemorrhagic cord lesions found on MR were associated with significant, persistent cord deficits, the authors conclude that MR provides a practical tool for diagnosis/prognosis in children with acute/subacute spinal injury.

Background: Noninvasive surveillance of patients after carotid endarterectomy is practiced routinely to detect recurrent stenoses. Many authors advocate repair of asymptomatic severe stenoses so detected. The likelihood of these lesions causing neurologic symptoms is unknown. Our aims were to (1) define the incidence of lesions, (2) determine the frequency of associated neurologic symptoms, and (3) identify patient-dependent factors that might predict restenosis., Methods: Data on the status of 449 carotid arteries after endarterectomy were reviewed. The number of recurrent and residual severe (greater than or equal to 80%) stenoses was identified. Interval to development of symptoms was determined by life-table analysis. Patient-dependent factors (age, gender, smoking, diabetes, and patch closure) were evaluated by univariate and multivariate analysis to identify possible associations with severe lesions., Results: Severe (greater than or equal to 80%) stenoses were seen in 35 patients (7.9%). Residual lesions were seen in 17 cases (eight occlusions and nine stenoses); recurrent lesions were identified in 18 patients (3.9%). Symptoms developed in five cases (14%) (one residual and four recurrent) 35, 48, 68, 98, and 103 months after surgery. The likelihood of developing symptoms associated with stenosis at 5 years was 6%. No factors correlated with residual stenosis. Age less than 60 years, female gender, primary closure, and absence of diabetes were more common in patients with recurrent lesions., Conclusions: Severe lesions can be found after carotid endarterectomy in at least 8% of patients and consist of residual defects, as well as recurrent stenoses. Recurrent lesions are more common in specific patient subgroups. These lesions are stable for long periods and the majority remain asymptomatic. Operation is not indicated unless symptoms develop in these patients. Intraoperative completion evaluation may be indicated to reduce the incidence of residual disease. Early noninvasive evaluation is useful as a quality-control measure. Repeated surveillance may provide data on the course of restenosis or contralateral disease progression but is of limited clinical benefit.

Arachnoid cysts are neurosurgical entities that have long been considered to be congenital in origin. Many examples in the literature suggest that there is a subgroup of arachnoid cysts that are required. The authors present the clinical history of a 17-month-old girl who developed two cerebellopontine angle arachnoid cysts after posterior fossa surgery for a brain tumor. After surgical excision of the tumor the child developed a left cerebellopontine angle cyst. This was treated through a suboccipital craniectomy by evacuating the cyst and excising the cyst wall. Two months later the child developed a second right-sided cerebellopontine angle cyst. It was treated by inserting a cystoperitoneal shunt. This article presents the case with radiological evidence of the acquired nature of the cysts. It also includes a brief review of the clinical presentation, pathogenesis, radiological evaluation, and surgical treatment of arachnoid cysts with emphasis on those occurring in the posterior fossa.

A retrospective review was undertaken of a random sample (N = 73) comprising 50% of carotid endarterectomies performed during 1986 to evaluate the necessity of routine postoperative intensive care unit (ICU) admission after carotid endarterectomy. Severity of illness was determined with use of the Acute Physiology Score of the APACHE II system. The Therapeutic Index Scoring System was used to quantify postoperative services used. Postoperative morbidity was analyzed. Financial impact was extrapolated with use of 1990 billing data. Length of ICU stay was 24.5 hours. Only 13 of 73 patients (18%) required ICU services. In 10 (77%) of these patients therapy was initiated in the recovery room and discontinued in six patients within 3 hours of ICU admission. Only two patients required ICU services for 16 hours after surgery. The mean Acute Physiology Score was low (4.96) and could not identify patients who required unique ICU services. Neurologic deficits were seen in five patients (6.9%). In three cases deficits were recognized in the recovery room; deficits developed in two patients after discharge from the ICU. Observation in the recovery room with transfer of stable patients would have eliminated ICU admission in 60 patients (82%). In 1990 the incremental ICU charge was $720/patient day. This represents 12.5% of the hospital charges for carotid endarterectomy. The ICU is an expensive and highly used hospital resource. Only a few patients need unique ICU services after carotid endarterectomy, and this is usually apparent within 2 hours of surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

A case of Arnold-Chiari malformation (Chiari type II) is reported to describe the usefulness of metrizamide cisternography in the diagnosis and management of this condition.

In "primary arterial occlusions of children", an unusual collateral circulation has been described first by Japanese, and later by others worldwide. As experience was gained some workers started to realize that the "typical angiographic appearance" could be found in several disease entities. It thus became evident that angiographic differentiation is important. In this communication we wish to discuss this entity and outline its significance as well as emphasize the pitfalls.

Familial congenital spinal arachnoid cysts causing progressive paraplegia are reported in two adolescent siblings as part of a hereditary syndrome. The other features of this unusual dominantly inherited disorder include double rows of eyelashes, partial ectropion of the lower eyelids, and acquired late-onset lymphedema of the lower extremities. The siblings' mother, who had roentgenographic evidence of a similar intraspinal lesion, was free of neurological symptoms but had the other characteristic features. Surgical treatment of the arachnoid cysts improves the progressive paraplegia.

A practical protocol for evaluating and monitoring head injured patients has been presented. It has been stressed that monitoring is an ongoing process which begins with the initial evaluation and continues throughout the patient's hospital stay. The level of monitoring and thus the parameters to be monitored are determined on an individualized basis according to the patient's clinical status and his level of stupor and coma. It has been suggested that for mild head injuries, adequate monitoring includes periodic evaluation of the neurological status and vital signs; but the more severely injured patients require extensive and frequent monitoring of a large number of clinical and physiological parameters. Among the many parameters, the continuous monitoring of ICP and the respiratory system are perhaps the most useful indicators of the patient's condition. Several methods for continuous ICP monitoring which are readily adaptable to most neurosurgical practices have been discussed. These include the intraventricular catheter, subarachnoid screw, and the closed Rickham reservoir connected to a ventricular catheter. In our institution, the Rickham reservoir has been used to monitor ICP and at the time of this report, satisfactory ICP recordings have been obtained in 27 of 30 head injury patients. Although this method requires a small surgical procedure, we believe that the decreased incidence of infection, the rapid access to ventricular fluid, and its potential for long term monitoring justify its use. Suggestions for monitoring other physiological parameters have also been presented. Particular emphasis has been placed on the management of infants and children with head injuries. The clinical entity of chronic subdural hematoma in infants and children has been used to illustrate the value of ICP monitoring as a guide to further treatment. Finally, we have briefly discussed the place of computers in day to day patient care, research, and monitoring.

A technique involving the combined use of Amipaque (metrizamide) and computerized tomography scanning is described for the evaluation of ventriculoperitoneal and ventriculoureteral shunt function. The results of three illustrative cases from a series of nine patients are given. In five patients, the technique demonstrated obstruction that was later confirmed at surgery. In the other four patients, it showed patency in the shunt system, and no surgery was performed, thereby obviating unnecessary shunt revisions.

Benign hemangioendothelioma is rarely included in discussions of vascular neoplasms involving the central nervous system, whereas it is a well-defined entity outside the neuraxis. We present four cases of benign hemangioendothelioma, including an infantile hemangioendothelioma with venous drainage into the transverse dural sinus, an intracranial hemangioendothelioma adherent to the falx cerebri, a spinal epidural hemangioendothelioma causing spinal cord compression, and a parasellar hemangioendothelioma. Although hemangioendothelioma resembles hemangioblastoma in some ways, it is a distinct entity differing from the other vascular lesions involving the central nervous system.

The problems experienced by a hospital pharmacy department in implementing a stand-alone packaged computer system are discussed, and recommendations for avoiding and managing these problems are presented. In 1984, a stand-alone packaged computer system was implemented in a 580-bed, tertiary-care institution that provides services from a central pharmacy and five satellite pharmacies. The department developed a request for proposal and contracted with a vender for a system that would support unit dose drug distribution and i.v. admixture services. During the implementation process, the following problems were experienced: The hardware was insufficient for the department's workload, the software design was limited, and personnel were frustrated with learning to use the system. These problems were intensified by the heavy workload and the large number of users. In the 18 months since implementation, the department has purchased more hardware, improved the software applications, and resolved many of the problems associated with employee frustration. Pharmacy departments at other large institutions might avoid some of these problems by training personnel adequately before implementation and by researching and estimating hardware and software needs in advance. In this large hospital, the efficiency of a stand-alone packaged pharmacy computer system has improved 18 months after implementation.

Three cases of rare primary intracranial yolk sac tumor are reported. Two cases had a pineal location, whereas the third presented as a suprasellar mass. After the placement of ventriculoperitoneal shunts for relief of hydrocephalus, all of the patients developed metastases restricted to the peritoneum, as demonstrated by autopsy in one patient (Case 1) and clinical and radiographic evidence in two patients (Cases 2 and 3). The peritoneal metastases were directly associated with the death of one patient, but were successfully treated with chemotherapy in another patient, who is still alive more than 2.5 years after initial presentation. The value of ascitic fluid cytology and alpha-fetoprotein determination in the diagnosis of this complication was demonstrated in one patient. These cases emphasize the need for awareness of this mode of metastasis and its potentially lethal effect.

The acute effect of i.v. spironolactone dissolved in ethanol on renal digoxin clearance was studied in 10 dogs. All dogs received i.v. digoxin (0.02 micrograms/kg/min) and 0.9% saline (30 ml/kg of bolus and 0.1 ml/kg/min for maintenance) throughout the study. After 2 hr of equilibration, four 15-min urine collections were made. The dogs then received, over 1 hr, a loading infusion of 4 mg/kg of spironolactone in ethanol (group 1, N = 6) or ethanol alone (group 2, N = 4). Thereafter the infusion was maintained at one-tenth the initial rate for eight 15-min periods. Three additional control dogs received ethanol plus spironolactone without digoxin. Digoxin radioimmunoassay of plasma and urine from these control animals did not reveal any significant cross-reactivity between spironolactone and the antibody of the digoxin radioimmunoassay. The digoxin clearance (CDIG) and ratio of CDIG to inulin clearance (CDIG/CIN) increased insignificantly with ethanol alone, but were respectively reduced by 21 and 28% with spironolactone (P less than .05). The reductions of CDIG and CDIG/CIN were observed immediately after the spironolactone loading infusion and were associated with a sudden rise in plasma digoxin. The changes in digoxin handling with spironolactone appeared to be temporally dissociated from the antimineralocorticoid activity of spironolactone. We conclude that spironolactone inhibits renal CDIG by a mechanism that may be independent of its antimineralocorticoid activity.

A review was undertaken of all patients seen in our institution between January 1978 and March 1987 in whom a cerebral CT scan was obtained in association with elective carotid endarterectomy. Three hundred fifty-nine such patients were identified. In a subgroup of 89 patients who were neurologically normal after carotid endarterectomy, scans were performed at least 48 hours after surgery to quantitate the incidence of silent postoperative infarction. These scans were interpreted by one neuroradiologist. Preoperative cerebral CT scans showed ipsilateral infarction in 146 of 359 patients (40.6%). Ipsilateral infarction was most common in patients with stroke (76%) but was also seen in 32.8% of patients with transient ischemic attacks, in 9 of 40 patients (22.5%) with nonhemispheric symptoms, and in 9 of 45 patients (20%) with asymptomatic hemodynamically significant carotid stenosis. The postoperative stroke rate was not significantly increased by the presence of infarct on preoperative cerebral CT scan (2.6% vs 1.9%). New infarcts were seen on cerebral CT scanning after carotid endarterectomy in 2 of 89 patients with no detectable neurologic abnormality (2.3%). This study demonstrates a high frequency of ipsilateral infarction in patients having elective carotid endarterectomy, even in those patients with clinical symptom complexes thought by many physicians to be relatively benign (i.e., transient cerebral ischemia, nonhemispheric ischemia, and asymptomatic carotid stenoses).(ABSTRACT TRUNCATED AT 250 WORDS)

Ten childhood cerebellar glioblastomas have been reported previously in the world literature. The authors report a case arising de novo in a 9-year-old child and stress the rarity of this tumor.

Examining techniques for radioimmunoassay of digoxin in urine, we found that the apparent concentration of digoxin is affected by endogenous substances, independent of the concentration of digoxin itself. We describe a modification of the Becton Dickinson solid-phase RIA that makes it more nearly accurate and more easily performed, and obviates the endogenous interference. Digoxin concentrations from 5.0 to at least 1000 micrograms/L can be measured.

Intramedullary enterogenous cysts of the cervical spinal cord are rare. We report a case of symptomatic recurrence of this type of cyst 8 years following its original surgical treatment.

A newborn baby girl with intracranial extracerebral glioneural (brain) heterotopia in the right frontoparietal area is described. The heterotopic brain was predominantly composed of neuronal and glial elements, with partial cerebellar differentiation. It also contained well-differentiated adipose tissue. The possible mechanism for its origin and the causes of central nervous system heterotopia are discussed.

Experience with 1035 carotid endarterectomies in a single community over a 2-year period was analyzed. Twenty-two surgeons working in six hospitals were involved. All surgeons had full-time or part-time appointments at the University of Rochester, 18 had special interest in vascular surgery, and eight had obtained a certificate of qualification in vascular surgery. Mortality rate was 1.4% (14 deaths), with additional permanent, nonfatal, neurologic morbidity of 3.4%. Mortality and morbidity were independent of surgeon, caseload, or hospital. Age and prior history of myocardial infarction influenced the incidence of postoperative myocardial infarction but not the incidence of death or neurologic morbidity. Factors that increased the risk of postoperative death or neurologic complication included hypertension; contralateral carotid disease as manifested by stroke, endarterectomy, or occlusion; whether the patient was a woman; and symptoms of crescendo ischemia. Lack of preoperative neurologic symptoms was correlated with decreased risk of myocardial infarction and neurologic complications. Overall mortality and neurologic morbidity associated with operation for "asymptomatic stenosis" was 3.1% (seven of 222 cases). However, the incidence of contralateral carotid disease was high in the patients in the asymptomatic group (60%), and all complications in this group occurred in patients with prior contralateral carotid endarterectomy or occlusion (p less than 0.05).

In this report we have discussed the complications of surgery for subdural hematoma. The complications are varied and many depend primarily on the type of treatment required by the patient. We have considered the problems associated with: percutaneous tap in infants, subdural shunts in infants and children, craniotomy for membranectomy, twist-drill drainage, and burr holes, craneictomy, and/or craniotomy. Infection, epilepsy, and reaccumulation of the subdural hematoma are common to all forms of therapy, while other complications are related to the specific form of subdural hematoma treatment. In addition, significant serum and electrolyte abnormalities which may occur as a consequence of subdural hematoma surgery have been reviewed. In general, the over-all complication rate of surgery for subdural hematoma is low in relationship to the morbidity and mortality associated with this lesion. Because of the frequency of subdural hematoma, the neurosurgeon should be ever vigilant in the prevention, recognition, and management of these complications.

Previous studies have shown that the concentrations of 3', 5' cyclic adenosine monophosphate (cAMP) and 3', 5' cyclic guanosine monophosphate (cGMP) in cerebrospinal fluid (CSF), brain, or both, are increased by melanotropic peptides and catechol amines, and by cholinergic agents. The present study measured the concentrations of cAMP, cGMP, and melanotropic activity in the CSF of normal patients and in 136 subjects with various neurologic diseases. In normal lumbar CSF, concentrations (ave +/- SD) were: cAMP, 21 +/- 8 mM; cGMP, 2.4 +/- 0.5 mM; melanotropic activity, 17 +/- 6 units/100 ml. Concentrations of cAMP, cGMP, and melanotropic activity did not differ significantly (P is less than .05) from normal in the following categories of adult and pediatric patients: back pain due to vertigo of unknown cause; cerebral atrophy; cerebral vascular disease; and brain tumor subdural hematoma not causing increased ventricular pressure. Nine children with retarded psychomotor development caused by diffuse brain disease (infection, trauma, hemorrhage, degenerative process, long-standing hydrocephalus with thinning of the cerebral mantle) had subnormal levels of cAMP and melanotropic activity. These two variables were significantly correlated in the entire series of CSF samples (r=+0.55, P is less than .005). cGMP was elevated in the ventricular fluid of adult and pediatric patients when the ventricular pressure was abnormally elevated. The nucleotide's level rose as high as 50 X normal when ventricular pressure exceeded 300 mm H2O. The concentration of ventricular cGMP was proportional to that of ventricular pressure (r=+0.76, P is less than .005). The correlation was similar regardless of the type of hydrocephalus (congenital or acquired, communicating or obstructive), the age of the patient, or the nature of the underlying disease.