Changes in cranial CSF volume during hypercapnia and hypocapnia

Magnetic resonance imaging was used to measure the effect of inhalation of 7% CO2 and hyperventilation with 60% O2 on human cranial cerebrospinal fluid volume. During CO2 inhalation there was a reduction in the cranial CSF volume ranging from 0.7-23.7 ml (mean 9.36 ml). The degree of reduction in cranial CSF volume was independent of the individual subject's increase in end-expiratory pCO2 or mean arterial blood pressure, in response to hypercapnia. During hyperventilation with high concentration oxygen the cranial CSF volume increased in all subjects (range 0.7-26.7 ml, mean 12.7 ml). The mean changes in cranial CSF volume, induced by hypercapnia and hypocapnia, were very similar to the expected reciprocal changes in cerebral blood volume.

Impact of a comprehensive health promotion curriculum on physician behavior and attitudes

Physician involvement with health promotion and disease prevention (HP/DP) is essential in the control of diseases in which behavioral risk factors are etiologically important. Yet physician involvement with health promotion is generally perceived as less than optimal. We report that an intensive, multifactorial curriculum introduced into a community hospital family medicine residency program increased physicians' use of preventive strategies with their patients and facilitated their use of specific, easy-to-follow protocols for the management of common problems amenable to health promotion.

Detection and treatment of hypercholesterolemia in a biethnic community, 1979-1985

Although hypercholesterolemia has been recognized as a risk factor for coronary heart disease (CHD) for decades, only in recent years have clinical trials definitively shown the efficacy of lowering serum cholesterol to prevent the occurrence or worsening of CHD. In 1985, an NIH consensus conference published guidelines for the diagnosis and treatment of hypercholesterolemia. Prior to 1985, physicians and lay people alike were not yet convinced of the necessity to know one's cholesterol level, nor did they know what levels should be treated. In a community-based survey of cardiovascular risk factors, known as the San Antonio Heart Study, in which 1,932 Mexican-Americans (MAs) and 1,133 non-Hispanic whites (NHWs) were examined between 1979 and 1985, the authors found that only 36/501 MAs (7%) and 54/312 NHWs (17%) in the moderate- or high-risk categories were aware that their cholesterols were high. Of the total number aware, including those whose cholesterol levels were in the low-risk range, only 23/97 MAs (24%) and 29/108 NHWs (27%) were receiving dietary or drug treatment. Of those being treated, only 9/23 MAs (39%) and 12/29 NHWs (41%) were effectively controlled. Mexican-Americans were less likely to be aware of their hypercholesterolemia than non-Hispanic whites, but both ethnic groups had low levels of treatment.

Visceral surface oxygen tension in experimental colitis in the rabbit

The impairment of bowel healing that is characteristic of inflammatory bowel disease (IBD) is poorly understood. Because bowel healing is related to the adequacy of perfusion in other circumstances, we studied bowel surface oxygen tension (PSO2), which is related to bowel perfusion, in rabbits with IBD. Both cell-mediated (n = 17) and immune complex-mediated (n = 10) colitis caused marked attenuation of colon PSO2. Control (n = 13) left colon PSO2 was 36 +/- 5 (SEM) torr. In mild colitis, left colon PSO2 fell to 11 +/- 5 torr, and in severe colitis it fell to 4 +/- 1 torr (p less than 0.01 for each compared with control). These changes occurred irrespective of the mechanism of induction of colitis. Gastric and small intestinal PSO2 were unaffected. Hepatic and renal PSO2 were decreased in severe colitis only. The presence of decreased PSO2 was a better marker for the presence of IBD than was histologic evaluation. It is suggested that attenuation of PSO2 may be a marker for the physiologic activity of IBD. If this is so, PSO2 may prove a useful adjunct in the operative management of IBD.

Magnetic resonance imaging of acute subarachnoid hemorrhage

The feasibility, safety, and diagnostic value of magnetic resonance (MR) imaging versus computerized tomography (CT) scanning were compared in 30 patients with clinical evidence of subarachnoid hemorrhage. Subarachnoid blood was identified more often and more information was available about the site and source of the hemorrhage on MR imaging than on CT. Magnetic resonance imaging could be used safely both before and after the operation, provided that nonferromagnetic clips were used and that comprehensive monitoring and cardiorespiratory support were available. Postoperative studies showed that artifacts from metallic implants and from patient movement caused less image degradation on MR images than on CT scans.

Temporal physiochemical changes during in vitro relaxation time measurements: the cerebrospinal fluid

Documented relaxation time measurements of body fluids such as cerebrospinal fluid (CSF) vary considerably. This may be largely due to lack of an appropriate method of maintaining the in vivo physiological and biochemical characteristics of the fluid. We have developed an in vitro technique that maintains the in vivo characteristics of body fluid samples for a sufficiently long period to establish the true relaxation times. To illustrate this we studied changes in CSF pH, pO2, and pCO2, first as it equilibrated with air and then under anaerobic conditions as found in vivo. Relaxation times of CSF were then studied under aerobic and anaerobic conditions. Under the particular aerobic conditions used the pH and pO2 of CSF increased quickly and pCO2 fell within the first 30 min. By 3-4 h equilibration with air was complete. The T1 and T2 relaxation times of CSF decreased by 14 and 16%, respectively, as a result of these physicochemical changes. It is important that such changes be considered when relaxation measurements of any body fluid are performed in vitro and efforts to maintain the in vivo milieu should not be neglected.

Magnetic resonance imaging in acute head injury

Using cardiorespiratory monitoring and support equipment compatible with a low field (0.15 T) system, magnetic resonance imaging (MRI) of patients suffering acute head injuries proved to be both feasible and safe. An abnormality was demonstrated by magnetic resonance imaging in 46 of 50 patients examined within 7 days of head injury using T2 weighted (SE2200/80) and T1 weighted (IR2000/600/40) multislice sequences. IN contrast, computed tomography (CT) demonstrated abnormalities in only 31 of the 50 patients. Intracranial extracerebral space-occupying collections of blood were well shown by magnetic resonance imaging which provided especially clear definition in the posterior fossa, subtemporal and subfrontal regions. Magnetic resonance imaging was more sensitive to cerebral abnormalities associated with traumatic unconsciousness and detected parenchymal lesions both in patients in coma and in those who had lost consciousness for only a few minutes. Lesions seen with MRI but not with CT included non-haemorrhagic contusions and abnormalities thought to reflect shearing injuries of white matter and intracerebral vessels. Magnetic resonance imaging is an effective alternative to CT; the additional information it can provide should be valuable in increasing the understanding of the early effects and late consequences of a head injury.

Isolation and analysis of the gene encoding peripheral myelin protein zero

We have isolated the gene encoding the Schwann cell glycoprotein P0, the major structural protein of the peripheral myelin sheath. In rats and mice, this gene is split into six exons distributed over 7 kb of DNA. The segregation of these exons is consistent with the functional segregation of the P0 protein into extracellular, membrane-spanning, and cytoplasmic domains. We find that the P0 extracellular domain is similar in structure to a single immunoglobulin variable region domain. In contrast to prototypical immunoglobulin domains, however, this P0 domain is encoded by two exons, the partitioning of which provides genetic evidence for the evolution of immunoglobulin-related domains from an ancestral half-domain. We also describe procedures for transfection of cultures of nontransformed rat Schwann cells and use these procedures to show that the Schwann cell-specific expression of the P0 gene is controlled by cis-acting elements localized upstream of exon I.

Magnetic resonance imaging of renal transplants: initial experience

Magnetic resonance imaging (MRI) was used in 45 renal transplant investigations (38 patients) using a Picker 0.15 T resistive system and a localized surface coil. An attempt was made to define optimal sequences in the evaluation of both normal and pathological transplants. Three sequences were found to be of value; a T1 weighted sequence (IR2180/700/40) to assess corticomedullary differentiation and its loss in acute rejection and acute tubular necrosis, a T2 weighted sequence (SE2000/80) for assessment of renal vessels and disturbances in blood supply, and a STIR (short tau inversion recovery) sequence (IR800/100/40) to define further the distended collecting system in obstruction and the presence of any perirenal collection. Encouraging results have been obtained, particularly in cases of acute rejection. It is suggested that the MRI scan is a useful screening test in cases of clinical doubt and may even obviate biopsy in some cases.

Is cranial CSF volume under hormonal influence? An MR study

We used magnetic resonance to investigate the hypothesis that premenstrual neurological symptoms are due to cerebral oedema and brain swelling. Total cranial and lateral ventricular CSF volumes were measured midcycle and premenstrually in 20 women with a normal menstrual cycle, and similar measurements were made 2 weeks apart in 10 postmenopausal women and 10 men. Total cranial CSF volume increased premenstrually in 19 women. The mean premenstrual increase was by 11.5 ml. There was not a significant difference between those women who were taking an oral contraceptive and those who were not. The CSF volume did not change significantly on repeat measurement in men and postmenopausal women. The CSF changes observed reflect a reduction in brain volume and do not support cerebral swelling as the cause of premenstrual neurological symptoms.

Intracranial CSF volumes: natural variations and physiological changes measured by MRI

Cranial CSF volumes, for the first time including CSF in the subarachnoid space, can be measured by Magnetic Resonance Imaging (MRI). The MRI sequence causes signal from the grey matter and white matter to cancel producing a contrast of 200: 1 between a unit of CSF and a unit of brain. We have assessed the variations between normal individuals and investigated some of the physiological factors that might influence cranial CSF volumes. Total CSF volumes were measured in 64 normal subjects, aged from 18-64 years (mean 38 years). Ventricular, cortical sulcal and posterior fossa volumes were also calculated separately. In 20 females with a normal menstrual cycle, CSF volumes were measured mid cycle and premenstrually; 10 post menopausal females and 10 males were rescanned after an interval of 2 weeks. Total cranial CSF volume were calculated before and during inhalation of 7% CO2 and before and during hyperventilation while breathing 60% O2, in 12 normal subjects. Total intracranial CSF volume ranged from 57.1-286.5 ml. Total intracranial and cortical sulcal CSF volumes increased more steeply with age than ventricular or posterior fossa CSF volumes. Males had more cranial CSF than females. Total CSF volume increased premenstrually in 19 females. Males and post-menopausal females did not have a significant change in CSF volume, on repeat examination. CO2 inhalation produced a mean increase of paCO2 of 17.2 mmHg and CSF volume decreased in all subjects (mean 9.4 ml). Cranial CSF volume increased in 11 subjects during O2 inhalation (range -0.5 to +26.7 ml mean 10.9 ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Magnetic resonance imaging in the management of resistant focal epilepsy: pathological case report and experience of 12 cases

Clinical improvement in epilepsy following temporal lobectomy is more often obtained when an abnormality is found on subsequent histological examination. Pre-operative MRI demonstrated an abnormal signal in the temporal lobe of a patient with pathologically proven mesial temporal sclerosis with microvascular anomaly. MRI may therefore be helpful in the selection of patients for temporal lobectomy. MRI findings of 12 patients with resistant focal epilepsy are reviewed. A wide range of T1 and T2 weighting is suggested to maximise selection of patients.

Characterization of chromosomes with hybrid genes for Hb Lepore-Washington, Hb Lepore-Baltimore, Hb P-Nilotic, and Hb Kenya

This study concerns the characterization of chromosomes with hybrid genes for Hb Lepore-Washington (44 chromosomes), for Hb Lepore-Baltimore (5 chromosomes), for Hb P-Nilotic (8 chromosomes), and for Hb Kenya (7 chromosomes) by determining a relatively large number of restriction enzyme polymorphism. Two, and possibly three, different Hb Lepore-Washington chromosomes were identified by specific haplotypes, while the haplotype of the Hb Lepore-Baltimore chromosome had its own characteristic pattern. A likely conclusion is that the crossovers leading to the formation of these chromosomes have occurred as independent events within the populations. Chromosomes with the delta beta-Lepore-Washington hybrid gene maintained specific characteristics (such as increased Hb F levels in heterozygotes, and high or low G gamma values in this Hb F) which have been observed in normal individuals with chromosomes having comparable haplotypes. Only one haplotype was observed for each of the chromosomes carrying either the beta delta-P-Nilotic hybrid gene or the A gamma beta hybrid gene of Hb Kenya.

Syringomyelia: cyst measurement by magnetic resonance imaging and comparison with symptoms, signs and disability

The severity and distribution of symptoms and signs in patients with syringomyelia is considered to be dependent on the longitudinal and transverse dimensions of the syrinx and it is thought that clinical examination can identify the extent of the cyst. Magnetic resonance imaging has made the anatomical localisation of intramedullary spinal lesions more exact and probably more specific than previous methods of investigation. Syrinx length, diameters, cyst:cord and cord:canal ratios have been studied in 12 patients with syringomyelia to assess whether the dimensions of the syrinx relate to the clinical findings. The length of syrinx appeared to be related to cyst diameter, cyst:cord and cord:canal ratios. Patients with a small syrinx tended to have a small cyst diameter, and small cyst:cord and cord:canal ratios. No significant relationship was found between muscle wasting or weakness, distribution of sensory loss, degree of disability or distress and the dimensions of the syrinx. These findings should be borne in mind when surgical management is being considered.

Occupation and lung cancer risk among New Jersey white males

The association of occupation with lung cancer risk was examined in a case-control study conducted in six areas of New Jersey. The study included 763 white males with incident histologically confirmed primary cancer of the trachea, bronchus, and lung and 900 general population white male controls selected from driver's license and death certificate files. Altogether, 27 employment categories had a smoking-adjusted odds ratio (OR) of 1.3 or greater; five of these with significantly high OR contributed to an occupational population attributable risk of 13%. Masons and tilesetters; janitors and cleaners; printing workers; and trucking service, warehousing, and storage workers had significantly high risks overall and for longer durations of employment. Shipbuilding workers had significantly high risk overall and for short duration of employment. Although the excess risk for all shipbuilding workers was primarily among those with reported exposure to asbestos, the risk was also high among welders, burners, sheet metal workers, and boilermakers with no reported asbestos exposure.