Positron emission tomography reveals elevated D2 dopamine receptors in drug-naive schizophrenics.

In postmortem studies of patients with schizophrenia, D2 dopamine receptors in the basal ganglia have been observed to be more numerous than in patients with no history of neurological or psychiatric disease. Because most patients with schizophrenia are treated with neuroleptic drugs that block D2 dopamine receptors in the caudate nucleus, it has been suggested that this increase in the number of receptors is a result of adaptation to these drugs rather than a biochemical abnormality intrinsic to schizophrenia. With positron emission tomography (PET), the D2 dopamine receptor density in the caudate nucleus of living human beings was measured in normal volunteers and in two groups of patients with schizophrenia--one group that had never been treated with neuroleptics and another group that had been treated with these drugs. D2 dopamine receptor densities in the caudate nucleus were higher in both groups of patients than in the normal volunteers. Thus, schizophrenia itself is associated with an increase in brain D2 dopamine receptor density.

Incidental diagnosis of pregnancy on bone and gallium scintigraphy.

Bone and gallium scintigraphy were performed as part of the diagnostic workup of a 21-yr-old woman who presented at our institution with a history of progressively worsening low back pain over a 1-wk period of time. The angiographic phase of the bone scan demonstrated a well-defined radionuclide blush within the pelvis just cephalad to the urinary bladder with persistent hyperemia noted in the blood-pool image. We attribute these findings to a uterine blush secondary to the pronounced uterine muscular hyperplasia, hyperemia, and edema that accompany pregnancy. Gallium scintigraphy demonstrated intense bilateral breast accumulation of the imaging agent in a typical doughnut pattern which is commonly found in the prelactating and lactating breast. Also demonstrated was apparent gallium accumulation in the placenta. This case is presented to emphasize the radionuclide findings that occur during pregnancy, particularly the incidental finding of radionuclide blush during the angiographic phase of a radionuclide scintigraphy which should alert the nuclear physician to the possibility of pregnancy in a woman of childbearing age.

Primary intraspinal fibrosarcoma.

Fibrosarcomas of dura mater are very rare tumors representing only 0.5% of all central nervous system sarcomas. A higher incidence of dural fibrosarcomas has been reported in patients with neurofibromatosis. We present a case of spinal dura mater fibrosarcoma in a patient without neurofibromatosis. The diagnostic and therapeutic strategy in the clinical management is discussed.

Racial differences in Norplant use in the United States.

The introduction of the contraceptive implant Norplant has focused attention on how social factors may affect contraceptive use. In the United States, race is a central category of social organization which may impact Norplant use. I use data from the 1995 National Survey of Family Growth to answer three main questions. (1) Are women of color more likely to use Norplant? (2) To what extent can racial differences in Norplant use be explained by a structural bias in the provision of medical care? (3) To what extent can racial differences in Norplant use be explained by life circumstances which may affect individual women's contraceptive decisions? I find that African American and Native American women are more likely than white or Asian American women to be recent Norplant users. There are no differences in recent use by Hispanic origin. Both a structural bias in the provision of care and differences in life circumstances account for the disparity in Norplant use between African Americans and whites. However, none of the factors examined here explain Native American women's high rate of use. Concerns about health risks for Norplant use are also discussed. These findings point out the importance of examining structural, individual and health status factors in studies of the use of health services.

Brain ischemia.

The sensitivity of MRI to changes in water state and volume makes it the most desirable modality for imaging early brain ischemia. Its sensitivity is reflected in the ability to show ischemic changes in the white matter of the asymptomatic elderly, which are attributed to axonal loss, demyelination, and gliosis. In large infarcts, however, contrast enhancement with Gd-DTPA can be used to add specificity, should doubt exist as to the proper diagnosis. The ability of MR to image flow is a valuable adjunct, and MR angiography has the potential partially to replace invasive angiography. Applications of MR such as diffusion-perfusion studies, sodium imaging, and spectroscopy could all prove to be useful in the future.

Social distance and patients' rating of healthcare providers.

Racial inequity in the provision of healthcare is widely recognized. In this paper, I assess the role of social distance from healthcare providers in accounting for whites' higher rating of healthcare providers. Using data from the Detroit Area Study, I test whether having higher socioeconomic status, like most healthcare providers, and racial concordance with healthcare provider account for the gap in satisfaction between whites and African Americans. I find that socioeconomic status and racial concordance variables account for a portion of whites' higher rating of the respect shown by their healthcare provider. Racial differences in evaluation of time spent with healthcare provider are accounted for by socioeconomic status, but not racial concordance. As researchers explore the causes of and remedies for the racial disparity in use and evaluation of healthcare, the subtle and indirect effects of race on the patient-healthcare provider relationship must be considered.

Gallium scintigraphy in a case of septic cavernous sinus thrombosis.

Septic cavernous sinus thrombosis, a relatively uncommon disease entity, frequently can be fatal. Early diagnosis is imperative in order that appropriate treatment be instituted. A 59-year-old woman who was admitted to our institution with complaints of diplopia, blurred vision and fevers that developed following a tooth extraction is presented. Initial CT and lumbar puncture on the day of admission were totally normal. A repeat CT performed 48 hours after admission, on the same day as gallium imaging, demonstrated findings consistent with cavernous sinus thrombosis. Gallium imaging demonstrated intense uptake in the left cavernous sinus and left orbit as well as moderately increased activity in the right cavernous sinus and orbit, confirming infection. The patient was treated with antibiotics, and repeat CT and gallium imaging were performed ten days later, both of which demonstrated near total resolution of the disease process. Conceivably, if gallium imaging had been initiated on the day of admission it may have been the first study to demonstrate an infectious process in the cavernous sinus. Gallium imaging should be considered as a diagnostic tool in the noninvasive workup of this entity.

Brain calcification in Kallman's syndrome. Computed tomographic appearance.

We report a 21-year-old white male with Kallman's syndrome (gonadotropic hypogonadism, hyposmia and sensorineural hearing loss) with extensive brain calcification, demonstrated for the first time by computed tomography. The pattern and anatomic distribution of the extensive brain calcification is nonspecific, being indistinguishable from those seen in other causes of brain calcification (principally diseases related to a disturbance in calcium metabolism), despite the normal serum calcium levels found in this patient. This syndrome, therefore, should be considered along with Cockayne's, Kearns-Sayre and Down's syndromes, tuberous sclerosis, carbonic anhydrase II deficiency, congenital mental deficiency and idiopathic familial basal ganglia calcification as another developmental cause of brain calcification, which usually show no disturbance in serum calcium level.

Collision-induced liquid secondary-ion mass spectra of oxytocin derivatives. A study of the influence of modifications in the disulfide bond on the adjacent peptide bond cleavage.

The influence of the inductive effect of modifications in the disulfide bridge in oxytocin analogs on the cleavage of the neighboring peptidic bond was studied. A correlation between the inductive constant of the group in the disulfide bridge and the particular fragment ion abundance was observed.

Frequency and spectrum of abnormalities in the bone marrow of the wrist: MR imaging findings.

OBJECTIVE: To describe the frequency of marrow abnormalities on wrist MR imaging and the MR findings of these various abnormalities. DESIGN AND PATIENTS: Five hundred and nineteen patients were studied at 1.5 T. Two observers recorded the presence and location of avascular necrosis, occult fractures and arthritic edema [focal osteoarthritis, ulnolunate abutment, rheumatoid arthritis, septic arthritis, gouty arthritis and scapholunate advanced collapse (SLAC)]. RESULTS AND CONCLUSION: One hundred and eighty-seven (36%) patients demonstrated marrow abnormalities in the wrist, of which 101 were diagnosed as arthritis [64 (34%) as focal osteoarthritis, 17 (9%) as ulnolunate abutment, 15 (8%) as rheumatoid arthritis, 2 as septic arthritis, 2 as SLAC, and 1 as gouty arthritis]. Seventy-two patients had occult fractures and in 27 patients avascular necrosis was seen. MR imaging can reveal various abnormalities in bone marrow of the wrist when findings on radiography are normal or equivocal.

Gallbladder opacification in infants following high dose angiocardiography.

Seven infants in congestive heart failure underwent high dose angiocardiography for diagnosis of severe congenital heart disease and subsequently displayed delayed opacification of the gallbladder. Biliary excretion of sufficient volume to opacify the gallbladder occurred despite structurally normal kidneys and no evidence of renal failure. Decreased renal clearance of contrast due to generalized diminution of glomerular filtration is postulated. The high doses of contrast and slow renal clearance allowed a relatively increased rate of hepatobiliary excretion and subsequent observation of the opacified gallbladder on abdominal radiographs. This phenomenon may not be as uncommon as is generally thought but its timing and location often do not allow an opportunity to make this observation.

CT features of hemorrhagic malignant liver tumors.

Hemorrhage is a recognized occurrence in hepatocellular carcinoma but is infrequently seen with tumors metastatic to the liver. This complication was observed in three patients with primary hepatic malignancy and in four patients with hepatic metastases (melanoma, two; colon, one; breast, one) who were studied by CT. Hemorrhage occurred in the patient with metastatic colon carcinoma in the setting of anticoagulation. Definitive radiographic signs of hemorrhage were detected by CT in six of the patients, including hyperdense hepatic masses on noncontrast scans (four patients), high density peritoneal (one patient) and subcapsular fluid (one patient), and the hematocrit effect in peritoneal fluid (one patient). In three patients an irregular liver border adjacent to perihepatic fluid suggested the liver as the organ from which bleeding originated. There were four deaths, none of which was immediately related to the hemorrhagic complication.

Fungal sinusitis: diagnosis with CT and MR imaging.

Of 293 patients who underwent computed tomography (CT), surgery, and pathologic examination for chronic sinusitis, 25 had a diagnosis of fungal sinusitis at pathologic examination. Of these, 22 had foci of increased attenuation at CT (in four patients the mean representative CT number [Hounsfied unit] was 122.2 HU [SD, 8.2 HU]), and three did not. Of the 22, 19 patients (76%) met the CT criterion of this study (there was a 12% false-positive and a 12% false-negative diagnostic rate). Six of the 19 patients and one additional patient underwent magnetic resonance (MR) imaging, and all demonstrated remarkably hypointense signal characteristics on T2-weighted images. The findings at MR imaging therefore appear more characteristic of fungal sinusitis than the findings at CT. Furnace atomic absorption spectrometry showed increased concentrations of iron and manganese in mycetoma compared with their concentrations in bacterially infected mucus. This finding and the presence of calcium in the fungal concretion may explain the hypointense T2-weighted signal on MR images.