Cannabinoid hyperemesis: cyclical hyperemesis in association with chronic cannabis abuse.

BACKGROUND AND AIMS: To explore the association between chronic cannabis abuse and a cyclical vomiting illness that presented in a series of cases in South Australia. METHODS: Nineteen patients were identified with chronic cannabis abuse and a cyclical vomiting illness. For legal and ethical reasons, all patients were counselled to cease all cannabis abuse. Follow up was provided with serial urine drug screen analysis and regular clinical consultation to chart the clinical course. Of the 19 patients, five refused consent and were lost to follow up and five were excluded on the basis of confounders. The remaining nine cases are presented here and compared with a published case of psychogenic vomiting. RESULTS: In all cases, including the published case, chronic cannabis abuse predated the onset of the cyclical vomiting illness. Cessation of cannabis abuse led to cessation of the cyclical vomiting illness in seven cases. Three cases, including the published case, did not abstain and continued to have recurrent episodes of vomiting. Three cases rechallenged themselves after a period of abstinence and suffered a return to illness. Two of these cases abstained again, and became and remain well. The third case did not and remains ill. A novel finding was that nine of the 10 patients, including the previously published case, displayed an abnormal washing behaviour during episodes of active illness. CONCLUSIONS: We conclude that chronic cannabis abuse was the cause of the cyclical vomiting illness in all cases, including the previously described case of psychogenic vomiting.

Latex protein: a hidden "food" allergen?

Avoidance of latex allergens is the primary method to prevent adverse reactions. Natural rubber latex is found in many different products in both the health care industry and in modern society, and consequently results in unexpected exposures of sensitized individuals. The use of latex gloves by food handlers provides one potential route for inadvertent exposure to latex allergens. In this study we have used two immunological methods to determine whether latex proteins are transferred to foods following contact with latex gloves. Direct transfer of latex protein to cheese was visualized using a modified immunoblot method. Sliced cheese was touched with a gloved finger. A nitrocellulose membrane was applied to lift the potential fingerprints and a rabbit anti-latex antiserum was used to visualize the transfer of any latex finger-prints. After handling lettuce with gloves, transferred protein was recovered by extracting the lettuce and quantified using an inhibition ELISA for latex proteins. Fingerprints of latex protein were readily detectable on cheese after contact with powdered latex gloves, but not with vinyl gloves. Furthermore, powdered latex glove use resulted in measurable amounts of latex protein on lettuce with an exposure-dependent increase in the latex protein levels. Lettuce alone or lettuce handled with vinyl gloves was negative for latex protein. The use of latex gloves by food handlers is the source of an indirect food additive in the form of latex proteins. It is recommended that food handlers avoid the use of latex gloves to eliminate inadvertent exposure of latex-sensitive individuals.

A functional cra gene is required for Salmonella enterica serovar typhimurium virulence in BALB/c mice.

A minitransposon mutant of Salmonella enterica serovar Typhimurium SR-11, SR-11 Fad(-), is unable to utilize gluconeogenic substrates as carbon sources and is avirulent and immunogenic when administered perorally to BALB/c mice (M. J. Utley et al., FEMS Microbiol. Lett., 163:129-134, 1998). Here, evidence is presented that the mutation in SR-11 Fad(-) that renders the strain avirulent is in the cra gene, which encodes the Cra protein, a regulator of central carbon metabolism.

Prediction and evaluation of solar particle events based on precursor information.

Protection from the radiation effects of solar particle events for deep space mission crews requires a warning system to observe solar flares and predict subsequent charged particle fluxes. Such a system relates precursor information observed in each flare to the intensity, delay, and duration of the subsequent Solar Particle Event (SPE) at other locations in the solar system. A warning system of this type is now in operation at the NOAA Space Environment Services Center in Boulder, Colorado for support of space missions. It has been used to predict flare particle fluxes at the earth for flares of Solar Cycle 22. The flare parameters used and the effectiveness of the current warning system, based on Solar Cycle 22 experience, are presented, with an examination of the shortcomings. Needed improvements to the system include more complete observations of solar activity, especially information on the occurrences of solar mass ejections; and consideration of the effects of propagation conditions in the solar corona and interplanetary medium. Requirements for solar observations and forecasting systems on board the spacecraft are discussed.

Craniopharyngioma: CT and MR imaging in nine cases.

Magnetic resonance (MR) imaging and CT examinations were performed in nine patients with surgically proven craniopharyngioma. Computed tomography was found to be superior to MR in detection of calcification and cyst formation. Extent of involvement of adjacent structures (e.g., optic chiasm, third ventricle, and intracavernous carotid artery) was more clearly delineated by MR. Craniopharyngioma fluid collections were found to be uniformly bright on T2-weighted sequences. However, on T1-weighted sequences, the signal intensity of the fluid ranged from hypointense to hyperintense, reflecting the heterogeneous contents of cysts in these tumors. Since calcification and cyst formation are hallmarks of craniopharyngiomas, we believe that CT is more specific than MR in diagnosis of craniopharyngiomas. Magnetic resonance, however, offers a more accurate assessment of the tumor extent.

MR imaging of recent spinal trauma.

Proper therapeutic management of acute spinal trauma depends considerably on the assessment of the condition of the underlying spinal cord and the relative stability of the surrounding bony architecture. A series of 14 patients who were examined by magnetic resonance (MR) imaging following spinal trauma is presented. Comparison of information gained by MR with that obtained by conventional CT indicates that MR is useful in assessing spinal cord compression, traumatic disk pathology, and post-traumatic intramedullary abnormalities. Computed tomography is more accurate in detecting posterior neural arch fractures and in assessing the number of displaced fragments.

Phenytoin removal during plasma exchange.

Plasma exchange is currently being used to treat a variety of disorders including immune complex and hematologic disorders. It has been shown that the removal of plasma removes drugs bound to plasma proteins. This case documents the removal of phenytoin during plasma exchange therapy. Total and free phenytoin serum concentrations were obtained before and after each exchange. Aliquots were obtained from each pass, and total phenytoin concentrations were determined. The total phenytoin serum concentration increased during the first exchange, while the total concentration decreased as a result of the second exchange. It was determined that approximately 27.7 mg and 30.4 mg of phenytoin were removed by the first and second plasma exchanges, respectively.

Primary glioma: diagnosis with magnetic resonance imaging.

Seventeen patients with surgically documented primary glial-origin brain tumors were evaluated by magnetic resonance imaging and high-resolution computed tomography. The exclusion of CT ring-enhancing lesions directed the focus of this study toward lower grade tumors that were more difficult to diagnose. The computed tomography abnormalities were often subtle and included areas of low attenuation, mass effect, and focal enhancement. Spin-echo sequences with both heavy T1 and T2 weighting were utilized. Prolonged T1 and T2 values were observed in all tumors. The T2-weighted spin-echo 1000/120 sequence was the most sensitive in tumor detection and was positive in all cases. Magnetic resonance imaging was superior to computed tomography in tumor detection, tumor localization, assessment of tumor extent, and determination of associated changes, ie, brain stem encroachment. All the magnetic resonance sequences used showed an increase in severity of imaging changes with increasing tumor grade. The T2-weighted sequence showed progressive margin irregularity, whereas the T1-weighted (inversion recovery) sequence showed increasing severity of internal tissue changes. The superior resolution of these changes by magnetic resonance imaging may have implications for better assessment of tumor grade in the future than is currently possible with computed tomography.

Dyke Award. Evaluation of contrast-enhanced MR imaging in a brain-abscess model.

An alpha-streptococcus brain abscess was produced in five dogs and studied with magnetic resonance (MR) imaging (0.5 T) and computed tomography (CT). Non-contrast- and contrast-enhanced CT scans were obtained using gadolinium diethylenetriamine-pentaacetic acid (Gd DTPA) for MR imaging and meglumine iothalamate for CT scanning. Each animal was evaluated in the early and later cerebritis stages of abscess evolution. On MR, the area of cerebritis enhanced after administration of Gd DTPA in a manner similar to that observed with contrast-enhanced CT. However, contrast enhancement was greater on the MR examination. Early lesions in two animals were detected only with contrast-enhanced MR imaging. This experience suggests that intravenously administered agents such as Gd DTPA should increase the diagnostic potential of MR imaging in neurologic diseases, especially those altering the blood-brain barrier.

Diagnosis of spinal arteriovenous malformation in a pregnant patient by MR imaging.

An intraspinal arteriovenous malformation (AVM) was diagnosed by magnetic resonance imaging in a pregnant patient. Serpentine areas of low signal intensity surrounded by cerebrospinal fluid were considered diagnostic of this surgically verified abnormality. In addition, T2 weighted images helped to determine the extent of the spinal canal occupied by the AVM.

Magnetic resonance imaging of multiple sclerosis: a study of pulse-technique efficacy.

Forty-two patients with the clinical diagnosis of multiple sclerosis were examined by proton magnetic resonance imaging (MRI) at 0.5 T. An extensive protocol was used to facilitate a comparison of the efficacy of different pulse techniques. Results were also compared in 39 cases with high-resolution x-ray computed tomography (CT). MRI revealed characteristic abnormalities in each case, whereas CT was positive in only 15 of 33 patients. Milder grades 1 and 2 disease were usually undetected by CT, and in all cases, the abnormalities noted on MRI were much more extensive than on CT. Cerebral abnormalities were best shown with the T2-weighted spin-echo sequence (TE/TR = 120/1000); brainstem lesions were best defined on the inversion-recovery sequence (TE/TI/TR = 30/400/1250). Increasing TE to 120 msec and TR to 2000 msec heightened the contrast between normal and abnormal white matter. However, the signal intensity of cerebrospinal fluid with this pulse technique obscured some abnormalities.

Salicylate removal during plasma exchange in normal volunteers.

The removal of salicylate by plasma exchange in normal subjects was studied. Six healthy men volunteers were given aspirin 975 mg every six hours for five days before undergoing plasma exchange. Blood samples for determination of serum salicylate concentrations were obtained from each subject before the 0730 aspirin dose on study days 3-6 and at hourly intervals for several hours before and after plasma exchange, which was performed at approximately 1500 on study day 5. Blood cell counts, serum albumin concentrations, and other blood chemistry values were also evaluated. Salicylate concentrations in serum and in plasma removed by exchange were determined spectrophotometrically. In each subject, serum salicylate concentrations before and after plasma exchange were compared, as were total area under the serum concentration-time curve and salicylate clearance on and off plasma exchange. The mean trough salicylate concentration at 1930 after plasma exchange on day 5 was significantly lower than the mean trough concentration at 1330 before plasma exchange on the same day. The mean AUC during the six-hour period in which plasma exchange occurred was significantly smaller than the AUC in the six-hour period before plasma exchange. Serum albumin concentrations decreased by a mean of 1.7 g/dl as a result of plasma exchange; however, the mean +/- S.D. amount of salicylate removed was only 191.0 +/- 52.4 mg. The amount of salicylate removed by plasma exchange in this study does not appear to be clinically important.(ABSTRACT TRUNCATED AT 250 WORDS)

Intervertebral disk-space infection: CT changes. Work in progress.

Seven patients who had spinal interspace infections underwent clinical, laboratory, and radiographic examinations, and findings are reported. Lytic fragmentation of adjacent vertebral bodies is a characteristic appearance on CT scans. Sagittal-coronal reformations confirm the end-plate irregularity and establish the diagnosis. Since the changes of diskitis are delayed and often obscured by accompanying degenerative disease on plain radiographs, CT appears to offer a diagnostic modality that shortens the usual delay from onset of symptoms to diagnosis.

Neuroradiologic applications of intraarterial digital subtraction angiography.

In the neuroradiologic evaluation of 118 patients using intraarterial digital subtraction angiography definite advantages and disadvantages were defined. Advantages include reduction of contrast medium volume, catheter time, and patient risk and discomfort. It also aids in angiographic planning. The paramount disadvantage is less spatial resolution compared with conventional film angiography.

Limited value of CT brain scans in the staging of small cell lung cancer.

Computed tomography of the brain was performed as part of the initial staging evaluation of 84 patients with small cell lung cancer. Brain scans indicative of metastatic disease were obtained in 12 (14%) patients, two of whom had no neurologic signs or symptoms. One of these had no other extrathoracic disease. Brain scans without evidence of metastatic disease were obtained in 72 patients, 58 (80.5%) of whom had no signs or symptoms suggestive of metastatic intracranial disease. In the 14 patients with neurologic symptoms but negative computed tomographic scans, other explanations than brain metastases were found. It was concluded that head scanning is a sensitive and accurate method of detecting central nervous system metastases in patients with small cell lung cancer. However, head computed tomography should not be included as part of the initial staging evaluation of the neurologically asymptomatic patients. In only one of 60 such patients did the brain scan change the initial clinical staging, which included chest films, liver and bone scans, and bone marrow biopsy.