Pheochromocytoma and paraganglioma: comparison of MR imaging with CT and I-131 MIBG scintigraphy

To ascertain the magnetic resonance (MR) imaging characteristics of pheochromocytomas and paragangliomas and to compare MR with computed tomography (CT) and iodine-131 metaiodobenzylguanidine (I-131 MIBG), 19 patients (18 with pheochromocytomas, one with a paraganglioma) were studied. The 18 patients with pheochromocytomas had had positive findings with I-131 MIBG scintigraphy. Abdominal pheochromocytomas were generally hypointense compared with normal liver on T1-weighted MR images and extremely hyperintense on T2-weighted MR images. MR imaging was preferable to CT in the evaluation of primary pheochromocytomas due to superior tissue characterization, particularly in the patient with hypertension and borderline catecholamine levels. For patients with recurrent or metastatic disease, the data suggest that I-131 MIBG scintigraphy is the examination of choice.     

Prevalence and determinants of hepatitis A virus exposure among prison entrants in Queensland, Australia: implications for public health control

In September 1997, a multicentre outbreak of hepatitis A virus (HAV) infection occurred in the Queensland prison system following a prolonged community-based HAV epidemic among illicit drug users. As part of the public health response, a cross-sectional survey was undertaken to estimate the seroprevalence of, and identify the determinants for, recent and past HAV infection among the incoming male prisoner population. Exposure data were collected through face-to-face interviews with 214 consenting inmates, whose sera were screened for immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies to HAV. Overall, 81 (37.9%) inmates were HAV-IgG seropositive, and four inmates were HAV-IgM seropositive, HAV-IgG seropositivity was strongly associated with year of birth (age) ( P _trend<0.0001), being born outside Australia (relative risk (RR) 1.9, 95% CI 1.4–2.7) and being of a non-English speaking background (RR 2.5, 95% CI 1.7–3.7). Lifestyle exposures (such as occupation, overseas travel and illict drug use) were not associated with an increased risk of HAV-IgG seropositivity. In contrast, all four HAV-IgM seropositive inmates were English-speaking, Australian-born males who used illicit drugs. These findings suggest that the risk factors for recent and past HAV infections among prisoners differ, with implications for HAV control in correctional settings. Strategies for HAV prevention, including routine screening of inmates and vaccination of susceptibles, are considered in the context of current models of disease transmission.     

Reverse Haemolytic Plaque Assay Study of Corticotropin-Releasing Hormone and Arginine Vasopressin Interaction in Ovine Corticotropes

Corticotropin-releasing hormone and arginine vasopressin are known to interact in stimulating secretion of adrenocorticotropin-related peptides from corticotropes. However, the mechanism mediating this interaction is uncertain. Recently, evidence has been provided using a reverse haemolytic plaque assay that in rat pituitary cells, arginine vasopressin potentiates the effects of corticotropin-releasing hormone by increasing the percentage of target cells that secrete adrenocorticotropin. To determine whether a similar mechanism also operates in the sheep corticotrope, which is reportedly more sensitive to arginine vasopressin than that of the rat, a reverse haemolytic plaque assay for β-endorphin secretion was used to study the response of ovine corticotropes to stimulation by increasing doses of corticotropin-releasing hormone or arginine vasopressin (0.1 nM to 10.0 nM) alone or in combination. In the reverse haemolytic plaque assay, β-endorphin antiserum at 1:50 and complement at 1:10 were found to be optimal dilutions for plaque formation. A concentration-dependent response curve to corticotropin-releasing hormone was obtained with a significant increase in plaque area from basal to reach maximal levels at 1.0 nM. Arginine vasopressin also stimulated an increase in plaque area, however, plaques formed were significantly smaller than those caused by corticotropin-releasing hormone. Since in the reverse haemolytic plaque assay, plaque area is related to the amount of hormone secreted by the cell, results demonstrate that although corticotropin-releasing hormone and arginine vasopressin both stimulate β-endorphin secretion from ovine corticotropes, corticotropin-releasing hormone is a more potent secretagogue than arginine vasopressin in that it causes the formation of significantly larger plaques. The addition of arginine vasopressin to low concentrations of corticotropin-releasing hormone caused plaque areas to reach maximal levels at 0.1 nM whereas these levels were only attained at 1.0 nM when corticotropin-releasing hormone was used alone. Therefore, arginine vasopressin interacts with corticotropin-releasing hormone to increase corticotrope responses by increasing their secretory response to corticotropin-releasing hormone. These data are consistent with previous work suggesting that arginine vasopressin increases the expression of corticotropin-releasing hormone receptors on the corticotrope cell surface. However, no significant increase in the percentage of plaque-forming cells was seen with either corticotropin-releasing hormone or arginine vasopressin alone or in combination implying that there was no recruitment of previously non-secreting cells.     

A drape for temporomandibular joint surgery

A method for draping in TMJ surgery including arthroscopy is presented using a urological drape. The advantage is that it allows movement of the mandible by the surgeon or assistant without their contamination by saliva.     

X-linked hypophosphatemia in adults: prevalence of skeletal radiographic and scintigraphic features

The radiologic studies of 38 essentially untreated adults with X-linked hypophosphatemia (XLH) were reviewed to determine the prevalence of radiologic features, to compare the findings in men and in women, and to elucidate the natural history of the disease by comparing the findings in young, intermediate-age, and older patients. Bone-reinforcement lines were common, but no characteristic mineral mass alteration was established. Looser zones were more prevalent in older subjects. Osteoarthritis was common, occurring in the ankles, knees, feet, sacroiliac joints, and wrists. Enthesopathy was infrequent in the younger group but was present in every member of the intermediate and older groups and was often accompanied by extra ossicles. Curvatures of the lower-extremity long bones were common in all age groups. Three new skeletal alterations in XLH were found to be common: flaring of the iliac wings, trapezoidal distal femoral condyles, and alterations in talar morphology, including shortening of the talar neck and flattening of the talar dome. Technetium-99m methylene diphosphonate scintigrams of 17 subjects were often abnormal, depicting bowing deformity and focal tracer accumulation in diaphyseal cortices and in periarticular and extraarticular regions. The mean metabolic index was moderately elevated (4.0). Both radiographic and scintigraphic findings were more severe in men, consistent with hemizygosity. The natural history of untreated XLH in both sexes is characterized by the development of a variety of age-related skeletal abnormalities during adulthood.     

Albumin synthesis rates are not decreased in hypoalbuminemic cachectic cancer patients with an ongoing acute-phase protein response.

OBJECTIVE: To determine whether suppression of albumin synthesis contributes to the hypoalbuminemia observed in weight-losing cancer patients with evidence of an ongoing acute-phase protein response (APPR). BACKGROUND DATA: Proinflammatory cytokines such as tumor necrosis factor (TNF) and interleukin 6 (IL-6) are known to downregulate albumin synthesis and increase acute-phase protein production in isolated hepatocytes. However, whether albumin synthesis is suppressed in hypoalbuminemic cancer patients with evidence of an ongoing acute-phase response is unknown. METHODS: Albumin synthesis rates were determined in six healthy controls and in six weight-losing pancreatic cancer patients with an ongoing APPR using a flooding dose technique with [2H5]-phenylalanine. The presence of an APPR was defined as a serum C-reactive protein concentration >10 mg/L. Serum cytokines (TNF, IL-6) and soluble TNF receptors (sTNF-R 55 and 75), along with serum cortisol and insulin, were also measured in both groups. RESULTS: Cancer patients had reduced serum albumin (median 32 [range, 23-36] vs. 42 g/L [40-45]; p < 0.01) and increased serum C-reactive protein concentrations (72 [23-126] vs. <5 mg/L; p < 0.01) when compared with controls. TNF was not detected in either group. sTNF-R 55 levels were significantly elevated in the cancer patients (3.8 [1.9-8.1] vs. 1.2 pg/mL [0.9-2.2]; p < 0.01). Circulating IL-6, insulin, and cortisol concentrations were not significantly different between the groups. The intravascular albumin mass was lower (88 [56-93] vs. 133 g [105-177]; p < 0.01), but the intravascular albumin fractional synthetic rate was higher (13.9 [13.5-18.5] vs. 10.3%/d [71-11.3]; p < 0.01) in the cancer patients compared with the controls. The total intravascular albumin synthetic rate was, however, similar between the two groups (12.7 [7.7-15.7] vs. 11.7 g/d [8.5-18.7]; p NS). CONCLUSIONS: In weight-losing pancreatic cancer patients with evidence of an ongoing APPR, hypoalbuminemia is not caused by a decreased rate of albumin synthesis.