Slow changes in cytosolic free Ca2+ in Escherichia coli highlight two putative influx mechanisms in response to changes in extracellular calcium.

Free intracellular Ca2+ ([Ca2+]i) in Escherichia coli was measured using the bioluminescent protein aequorin. Overall, the bacteria maintained a tight control on their free [Ca2+]i. The results indicated a slow Ca2+ influx, the magnitude of the initial rise in free [Ca2+]i being dependent upon the concentrations of external Ca2+. This was followed by the slow removal of free Ca2+ until normal levels were restored. Specifically, addition of external Ca2+ (0.25-10 mM) resulted in a gradual rise in intracellular free Ca2+ from a basal level of approximately 272 nM, maximally reaching a peak of 0.85-5.4 microM within 30-40 min. This was followed by a slow fall over the next 30 min, culminating in an oscillatory pattern of free [Ca2+]i (range 0.3-0.7 microM for 0.25 mM external Ca2+). In the presence of EGTA, free [Ca2+]i was dramatically reduced. Neither the influx of Ca2+ nor restoration of intracellular free Ca2+ required protein synthesis. Moreover, preincubation with Ca2+ increased the rising phase of intracellular Ca2+ in response to further exposure to external Ca2+. This was further evidence against a specific adaptation process such as the synthesis of calcium exporters. A putative Ca2+ influx channel was demonstrated in stationary phase cells in particular, which could be blocked by La3+. This channel was consistent with the voltage-activated poly-3-hydroxybutyrate/polyphosphate Ca2+ channels previously detailed by Reusch et al. [23] Even in the presence of La3+, however, the free [Ca2+]i of log phase and stationary phase bacteria still increased two-fold over resting values in response to external Ca2+. This suggested the presence of at least two Ca2+ influx processes, one inhibited by La3+ and the other not.

Predictive value of carotid bruit for carotid atherosclerosis.

To assess the predictive value of carotid bruit for moderate-to-severe carotid atherosclerosis, the results of carotid arteriograms performed on 1004 subjects were correlated with the findings of auscultation of the carotid arteries. Predictive values of carotid bruit for ipsilateral extracranial carotid atherosclerosis were 77% for localized bruits and 74% for diffuse bruits. The predictive values of extracranial carotid bruit for ipsilateral intracranial carotid atherosclerosis were 16% for localized bruits and 18% for diffuse bruits. Assessing both carotid arteries together, the predictive value of carotid bruit for moderate-to-severe atherosclerosis at any extracranial carotid site was 85%, there being no difference whether the bruits were diffuse, localized, bilateral, or unilateral. Diffuse or localized bruits, whether unilateral or bilateral, are equally predictive of moderate-to-severe atherosclerosis in the extracranial carotid artery, but both are poor predictors of intracranial carotid artery disease.

Pineal tumors. A 53-year experience.

Thirty-four patients with pathologically confirmed primary pineal tumors were evaluated at the Mayo Clinic from 1923 through 1976. All tumors were of germ cell or pineal cell origin. Most patients were adolescent boys with subacute increased intracranial pressure and Parinaud's syndrome. Hypothalamic symptoms were surprisingly infrequent. Direct surgical intervention was associated with high mortality, but has been more successful in recent years.

Predictors of intracranial carotid artery atherosclerosis. Duration of cigarette smoking and hypertension are more powerful than serum lipid levels.

The effect of cigarette smoking on intracranial internal carotid artery atherosclerosis (ICAS) was studied by obtaining cigarette smoking histories and data on other potential predictors, including serum lipid estimations, for consecutive patients undergoing carotid arteriography. The duration of cigarette smoking was the most significant independent predictor of the presence of ICAS. Other independently significant predictors of ICAS were hypertension, diabetes mellitus, and current systolic blood pressure. The interaction of diabetes and duration of smoking was a significant negative predictor. In patients for whom serum lipid values were available, lower levels of apolipoprotein A-I were associated with a higher risk of having ICAS. However, the effect of apolipoprotein A-I as a predictor of the presence of ICAS was far outweighted by the effects of duration of smoking and hypertension.

Assessment of roentgenographic lucencies of the skull: a systematic approach.

A review of roentgenologic characteristics of cranial vault defects suggests these criteria as favoring benign etiology: solitariness and small size, parasagittal location, smooth edges, sclerosis of margin, peripheral vascularity, and presence of bone remnants within the lesion. The more of these criteria that are present, the greater is the likelihood of benignity. Conversely, the presence of multiple defects of large size or scores of defects of small size, ragged undermined edges, total bone penetration, lack of peripheral vascularity, of absence of marginal sclerosis is presuptive evidence of malignancy.

Long-term prognosis after carotid artery occlusion.

One hundred thirty eight patients with angiographically proved carotid artery occlusion and minimal or no neurologic deficit were followed up for an average of 5 years. For patients 35 years old or over, the observed 5-year survival rate on an actuarial basis was 77% compared with an expected rate of 85% in a matched normal population. For patients 35 years old or over, the subsequent stroke rate was 3% per year, and two-thirds of the strokes were ipsilateral to the carotid artery occlusion. The observed stroke rate for all patients 35 years old or over was eight times the expected rate for a matched normal population. The relative risk of stroke was much greater in the younger patients with atherosclerotic carotid artery occlusion than in the older patients.

Evaluation of intracranial disorders in children by computerized transaxial tomography: a preliminary report.

Computerized transaxial tomography (CTT) is a nonivasive roentgenologic method that demonstrates the configuration of the intracranial contents, including the cerebral parenchyma and the ventricular system. Of 207 children examined by CTT, 53 later had neuroradiologic contrast studies or neurosurgical intervention, or both, and two came to autopsy. The neuroradiologic, surgical, and pathologic findings corresponded with the CTT findings in patients with large ventricles, dupratentorial tumors, intracranial hematomas or cysts, and epidural collections. The correlation was less concordant in patients with intracranial vascular malformations or lesions involving cranial bones. CTT promises to be valuable for diagnosis of many intracranial lesions in children.

Elevation of serum creatine kinase B-subunit levels by radiographic contrast agents in patients with neurologic disorders.

The effect of radiographic contrast agents on the central nervous system was evaluated by measurement of serum creatine kinase B-subunit (CKB) levels with use of radioimmunoassay in 58 patients who underwent computed tomographic (CT) scanning and 46 patients who underwent cerebral angiography for evaluation of cerebrovascular diseases, brain tumors, and other neurologic disorders. In 11 patients (10.6%), the CKB increased to abnormally high levels within 4 hours after the radiographic procedures, and the median value after 30 minutes was significantly higher than the corresponding precontrast value (P less than 0.01). Eight of the 11 patients had recent ischemic cerebrovascular diseases, and 7 of the 11 had undergone CT scanning. On the basis of the information available in the literature, elevation of the serum CKB levels may be interpreted as reflecting breakdown of the blood-brain barrier and neural damage. Intravascularly administered radiographic media are generally safe, but the results of the current investigation suggested the potential for detrimental effects, particularly in patients with recent cerebrovascular diseases.

Magnetic resonance imaging and clinical relationships in multiple sclerosis.

Magnetic resonance imaging (MRI) was done in 109 patients with suspected demyelinating disease (56 with clinical multiple sclerosis [MS] and 53 without). Of those with clinical MS, 43 (77%) had multifocal lesions of the white matter detected on MRI; 12 of the 43 also had confluent periventricular signaling. Nine patients (17%) without clinical MS had similar findings. Of the 56 patients with MS, 35 underwent both computed tomography (CT) and MRI. In this group, 80% of MRI scans showed multiple demyelinating lesions compatible with MS, as compared with 29% of the CT scans. A CT scan was "positive" more often if obtained within 1 month after an attack of MS than later. In contrast, the sensitivity of MRI or the number of lesions detected by MRI did not increase in patients with recent exacerbations. MRI was "positive" in patients with clinical MS more often than was any single evoked response study. In statistical analyses, both the sensitivity of MRI and the number of lesions were associated with the duration of MS. A pattern of confluent periventricular signaling around the lateral ventricle was associated with greater duration of MS and patient disability.

Magnetic resonance imaging in a routine clinical setting.

The results of magnetic resonance imaging (MRI) examinations in the first 1,000 consecutive patients who were studied by this technique at our institution were reviewed to determine the disease states encountered, the sensitivity and accuracy of results, and the value of the examination as compared with computed tomography and other imaging procedures. The MRI device was a 0.15-tesla resistive magnet that used a variety of saturation recovery, spin echo, and inversion recovery pulse sequences to produce images. MRI was found equal to or superior to other imaging techniques in most cases. Exceptions included organs or body regions that are prone to excessive respiratory or vascular motion, lesions that necessitate exquisite spatial resolution for diagnosis, and lesions in which angulation of the viewing plane is necessary for optimal depiction. Fresh blood and calcification within a lesion were also difficult to detect with use of MRI.

Serum lipids and lipoproteins are less powerful predictors of extracranial carotid artery atherosclerosis than are cigarette smoking and hypertension.

The effect of serum lipids and lipoproteins on extracranial carotid artery atherosclerosis (CAS) was studied in patients who underwent carotid arteriography. Serum lipid and lipoprotein values along with data on other potential predictors of extracranial CAS were determined in 240 patients who had at least one extracranial carotid artery visualized. In a multiple logistic regression analysis, the independently significant predictors of the presence of extracranial CAS were, in decreasing order of significance, duration of smoking of cigarettes, hypertension, age, and low-density lipoprotein cholesterol. Serum cholesterol, triglycerides, high-density lipoprotein cholesterol, and apolipoprotein A-I did not show an independent effect. Although low-density lipoprotein cholesterol was an independent predictor of the presence of extracranial CAS, its effect as a predictor was far outweighed by the effects of the duration of smoking of cigarettes and a history of hypertension.

Manifestations and management of laryngoceles.

Six cases of laryngocele are reported including 2 bilateral, external laryngoceles, 1 internal laryngocele associated with amyloidosis, and 3 combined laryngoceles. Laryngoceles occur predominantly in males. Cervical mass and hoarseness were the most common signs and symptoms. Bilateral, external laryngoceles that decompress spontaneously when intralaryngeal air pressure returns to normal were managed conservatively. Combined and internal laryngoceles should be removed surgically through an external, lateral neck approach. This approach is preferable to anterior laryngofissure because it avoids trauma to the anterior commissure and the true vocal cords. In addition, blunting of the anterior commissure and the risk of subglottic stenosis are avoided.

Aneurysmal bone cyst of the ethmoid.

Although nearly 500 cases of aneurysmal bone cyst have been recorded in the English literature, involvement of the facial bone is uncommon. To our knowledge, this is the first case of extragnathic, facial aneurysmal bone cyst to be reported in the English literature. A left ethmoid aneurysmal bone cyst was found in a 20-year-old pregnant woman who had a 5-month history of progressive left periorbital swelling, left cystic nasal mass, progressive nasal obstruction, blurred vision, and occasional diplopia. The diagnostic evaluation included a sinus series, facial lamiograms, and an EMI scan. Needle aspirates taken frequently from the intranasal cyst consisted of a dark bloody fluid. The surgical procedure, using external rhinotomy approaches, pathologic findings, and a literature review are presented.

Computer analysis of orbital fat and muscle volumes in Graves ophthalmopathy.

A technique using special computer programs and data from high-resolution computed tomographic scans has been developed that provides accurate and reproducible volume measurements for muscle and fat in the orbit. Normal values for retrobulbar fat and muscle were established in 19 adults. Nineteen patients with Graves exophthalmopathy were then studied, and a spectrum of change was found that included varying degrees of increased muscle volume or increased volume of both muscle and fat. Further categorization of these changes related to clinical characteristics should lead to a better understanding of the mechanism for ophthalmopathy in Graves disease.

Spontaneous cervical cephalic arterial dissection and its residuum: angiographic spectrum.

Cervical cephalic dissections are uncommon acute disruptions of the arterial wall occurring predominantly in middle-aged women. Clinically, most patients present with unilateral headache, oculosympathetic palsy, or ischemic neurologic symptoms. Usually, a single internal carotid artery, predominantly the right, is affected, but simultaneous multivessel dissections are evident in about one-third of patients. Angiographically, the appearance of the dissection varies, depending on its severity, extent, and the interval between onset and angiography. In the patients reported, the disruption was manifested initially by eccentric tapered stenosis in 47%, tapered stenosis and a dissecting aneurysm in 28%, occlusion in 18%, or a dissecting aneurysm alone in 7%. Subsequently, stenotic dissections resolved in 60%, improved in 20%, and progressed in 15%, while dissecting aneurysms diminished in half and resolved in one-fourth of patients. An angiographic residuum, temporally remote to its onset, was evident in 25% of dissections. Hence, carotid arterial dissections tend to resolve, sometimes progress, but seldom recur.

Nuclear magnetic resonance imaging.

Nuclear magnetic resonance scanning provides the potential for measurement of new properties of tissue which may permit better pathologic differentiation. NMR will be less affected by bone, and so neurologic studies in which bone artifacts are a problem in CT may be facilitated. Direct sagittal and coronal imaging are possible. As far as we know, the biologic hazards are expected to be minimal but cannot be definitely ruled out at this time. At present, the relaxation times that are most frequently measured are such that clinically acceptable spatial resolution (2 to 3mm) requires scan times on the order of two minutes or more. Whether chemical cross-sections that are acceptable to clinical demands can be obtained remains to be demonstrated.

Routine tomography of the temporomandibular joint.

Routine lateral tomography of the temporomandibular joint has resulted in a three-fold increase in the detection of positive findings. The technique is easily accomplished, eliminates the problem of superimposition of unwanted structures, permits a true lateral view of the condyle and condylar fossa, and allows small articular surface abnormalities to be identified. Although the entrance skin dose to the patient's face in the beam is about two times greater per exposure than that for our previous conventional open and closed lateral views, we believe that the increased dose is reasonable and the resulting improved diagnostic accuracy outweighs this disadvantage.

Radiologic evaluation of ischemic cerebrovascular syndromes with emphasis on computed tomography.

In patients with stroke syndromes, the extent and sequence of investigations are based upon clinical probabilities and take into account the age, general condition, and wishes of the patient. There is no doubt that the evaluation of such patients has been changed and improved by CT. The incidence of intraparenchymal bleeding is higher, but its mortality is lower than previously believed. The incidence of hemorrhagic infarction is probably not as great as previously suspected, but the hazards of anticoagulant therapy in a patient with a hemorrhagic infarct are easily obviated if a CT scan is obtained before anticoagulant therapy is started. The initial evaluation of the patient has been improved by CT, but in addition, following the course of the patient is easier by obtaining serial scans when satisfactory recovery does not take place or continue at the expected rate. Parenchymal changes such as hemorrhagic change, mass effect, or obstruction of the ventricular system can be detected early, and approached rationally.

Magnetic resonance imaging in syringomyelia.

Myelography and myelography assisted with computed tomography have been the most commonly used radiographic methods in the study of syringomyelia. These studies have never been entirely reliable in demonstrating the syrinx cavity and its relationship to other intracranial structures. During the 1st year of operation of the magnetic resonance imaging facility, the syringomyelic cavity was demonstrated in 15 patients who all had typical clinical signs and symptoms associated with syringomyelia. Nine cases were syringomyelia with Chiari malformation. One case showed additional hydrocephalus. Four cases were idiopathic, and 1 case was remotely posttraumatic. Magnetic resonance imaging, although it is in its infancy, already promises to be the most important radiographic technique for syringomyelia because it provides an anatomically truthful visualization of the sagittal plane of the cervical cord and can demonstrate the syrinx cavity and its relationship with the cerebellar tonsils, the 4th ventricle, and other related structures.

Correlation of radiological features to failure of lumbar intervertebral disc chemonucleolysis.

Chemonucleolysis was performed in 103 patients for lumbar disc prolapse. Multiple (two) interspaces were injected in only seven patients. Radiographically, all patients had myelographic or computerized tomography evidence of disc prolapse. Eighty-seven of 100 patients who were available for follow-up review had improved. Ten of 13 patients with persistent symptoms required a laminectomy. Altered spinal alignment was evident in five of the 13 patients with persistent symptoms: retrolisthesis in three and myelographic disc defect on the convex aspect of the scoliosis in two. Review of radiographic studies was carried out in an attempt to establish guidelines for patient selection so as to decrease the rate of failure in chymopapain treatment.