Nocturnal growth hormone secretion in schizophrenic patients and healthy subjects.

Plasma growth hormone concentrations were measured at hourly intervals between 10 p.m. and 8 a.m. the next morning in 15 drug-free chronic schizophrenic male inpatients and 14 healthy males. Growth hormone secretion was significantly lower in the patients as compared with the controls. Growth hormone release peaked around 1 a.m. in the controls, but a growth hormone peak was absent in the patient group. Increased dopamine activity, increased serotonin activity, or both could explain the absence of a nocturnal growth hormone surge in the schizophrenic patients.     

Complementary role of ambulatory electrocardiographic monitoring and exercise testing in evaluation of myocardial ischemia.

For detection of myocardial ischemia, exercise testing is a better tool than AEM and therefore should be preferred procedure for this purpose. In patients who exhibit ischemic changes on exercise testing, the presence of ischemic changes on AEM carries significant prognostic information beyond the results of exercise testing; therefore, it is recommended that this test be performed in those who have ischemic changes on exercise at a moderate or low workload. AEM together with exercise testing can be used to assess efficacy of anti-ischemic drugs, can help to define the underlying mechanism of ischemia during daily life, and in certain groups of patients, like those with unstable angina, peripheral vascular disease, or after cerebrovascular events, it can replace exercise testing as a method for detecting ischemic changes.     

HLA class II antigen expression in human papillomavirus-associated cervical cancer.

The observation that tumor cells of some neoplasms display major histocompatibility complex (MHC) class II molecules may be of functional significance, influencing the progression of malignancy by allowing the cancer cells to present antigen to the immune system. In the normal cervix, class II molecules are expressed by columnar but not squamous epithelium. The pattern of MHC class II expression in cervical carcinomas has been documented using immunohistochemical methods. Of 53 cervical squamous carcinomas examined for MHC class II expression, only 17% maintained a negative phenotype characteristic of the epithelium from which they were derived, while the remaining tumors exhibited either uniform (45%) or heterogeneous (38%) expression. Tumor areas which were class II positive also express class II associated invariant chain and the adhesion molecules lymphocyte function antigen 3 and intercellular adhesion molecule 1. The DR, DP, and DQ class II MHC subloci are differentially expressed, suggesting independent regulation. There is a trend for tumors with the uniform class II phenotype to predominantly express DR antigen, whereas tumors of the heterogeneous class II phenotype express with equal frequency either DR or DP antigens dominantly. There is no apparent influence of class II status on lymphocyte infiltration of the tumors. The presence of human papillomavirus 16 DNA in the cervical carcinoma specimens was analyzed by Southern blotting of restriction enzyme digested DNA and no correlation between the presence of human papilloma virus and MHC class II expression was found.     

The prognostic significance of glial fibrillary acidic protein staining in medulloblastoma

Histologic and immunohistochemical properties of 53 medulloblastomas were analyzed with regard to clinical features and survival rate. No correlation was found between survival rate and histologic features of the tumor, such as desmoplastic reaction, number of mitoses, hemorrhages, necrosis, endothelial proliferation, glomerular arrangement, calcifications, rosettes, or oligodendroglial cells. However 82% of the patients with positive glial fibrillary acidic protein (GFAP) staining in numerous tumor cells survived more than 5 years; only 30% survived that long if their tumor cells were GFAP negative (P = 0.0093). This significant difference was not related to the mode of therapeutic protocol used. The authors suggest that GFAP staining may be a useful prognostic tool in medulloblastoma.     

Incompatibility of contrast agents with intravascular medications. Work in progress

In vitro and in vivo precipitation of iodinated contrast agents when ioxaglate and papaverine are given together has been reported. To verify these reports and to investigate other medications not previously tested, the authors analyzed mixtures of contrast agents and medications in vitro with a light spectrophotometer and observed them for visible precipitates for up to 120 minutes. Previously reported incompatibilities between ionic or low-osmolality contrast media and medications were verified, and several new incompatibilities were discovered. No incompatibilities were found when the drugs tested were mixed with the new nonionic contrast media.     

The use of benzodiazepines in the management of behavioral symptoms in demented patients.

Hard data on the efficacy of benzodiazepines in the treatment of behavioral disturbances in Alzheimer's disease are not available. Short-acting benzodiazepines, such as oxazepam, appear safer than long-acting benzodiazepines and more efficient than placebo in the short-term (4-8 weeks) treatment of behavioral disturbances in geriatric, psychogeriatric, and demented patients. It is unknown whether oxazepam is superior to neuroleptic drugs or other commonly prescribed sedatives in this context. To some extent these findings may apply to patients with Alzheimer's disease as well, but there are several arguments against an uncritical extrapolation of conclusions drawn from other geriatric populations to patients with Alzheimer's disease. When, despite the lack of well-founded knowledge in this field, such a treatment modality is chosen, short-acting benzodiazepines should be preferred over long-acting agents. Drug interactions and pharmacokinetic aspects of the specific agent in the individual patient should always be considered carefully. Future studies on the treatment of behavioral disturbances in Alzheimer's disease need to clarify which specific behavioral symptoms should be treated pharmacologically, which therapeutic agents have the most advantageous risk-benefit ratio in this context, and what is the optimal treatment duration.     

Halothane inhibits two components of calcium current in clonal (GH3) pituitary cells.

The effect of halothane on isolated calcium (Ca2+) current of clonal (GH3) pituitary cells was investigated using standard whole-cell clamp techniques at room temperature. Halothane (0.1-5.0 mM) reversibly reduced both the low-threshold, transient [low-voltage-activated (LVA)] component and the high-threshold [high-voltage-activated (HVA)] component of Ca2+ current. Halothane had little effect on the voltage dependence of activation or inactivation of either component of Ca2+ current. Inhibition of the peak high-threshold Ca2+ current was half-maximal at about 0.8 mM halothane, with maximal inhibition (100%) occurring with 5 mM halothane. When measured at the end of a 190-msec command step, half-maximal reduction of high-threshold current occurred at less than 0.5 mM halothane. The low-threshold transient current was less sensitive to halothane, with half-maximal inhibition of peak transient current activated at -30 mV occurring at approximately 1.3 mM. The effect of halothane on the HVA current was apparently not mediated by changes in intracellular Ca2+ concentration. The ability of halothane to inhibit Ca2+ current was unaffected by either the inclusion of the rapid Ca2+ buffer 1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid (BAPTA) in the recording pipette or exposure of the cell to 10 mM caffeine. To assess the selectivity of the effect of halothane, the actions of halothane on two components of voltage-activated potassium (K+) current observed in the absence of extracellular Ca2+ and on voltage-dependent sodium (Na+) current were also examined. Halothane had no effect on the voltage-dependent, inactivating K+ current of GH3 cells at concentrations up to 1.2 mM. In contrast, the non-inactivating K+ current, though less sensitive to halothane than either Ca2+ current, was reduced by about 40% by 1.2 mM halothane at +20 mV. Peak Na+ current was also blocked by halothane, but 50% block required around 2.6 mM halothane with little effect at 1.6 mM. Reduction of Na+ current was associated with a substantial negative shift in the steady-state inactivation curve. Although the results indicate that a number of voltage-dependent ionic currents are sensitive to halothane, both components of Ca2+ current exhibit a greater sensitivity to halothane than any of three other voltage-dependent currents in GH3 cells. These results show that GH3 cell Ca2+ currents are selectively inhibited by clinically appropriate concentrations of halothane and that the reduction of Ca2+ current can account for the inhibition by halothane of TRH- or KCl-induced prolactin secretion in GH3 cells.     

Autosomal dominant transmission of isolated congenital vertical talus

We report vertical transmission of isolated congenital vertical talus through three generations of a Honduran family. Five of nine affected family members were examined and the diagnosis was confirmed radiographically. There was incomplete penetrance in one clinically unaffected woman with two affected children. Bilateral and unilateral involvement was seen with a wide range of severity. Based on this family and on cases reviewed from the literature, we propose that isolated congenital vertical talus can be inherited as an autosomal dominant trait with variable expression and incomplete penetrance.     

Childhood Malignant Thymoma: Clinical, Therapeutic, and Immunohistochemical Considerations

Malignant thymomas are among the least common mediastinal tumors in the pediatric age group. Thymomas are considered malignant on the basis of macroscopic and microscopic invasiveness. As only 20 well-documented cases involving children have been reported in the literature, the pattern of responsiveness to therapy and the value of prognostic signs is obscure. Two cases of malignant pediatric thymomas are reported with pathognomonic histoimmunological features of aggressive thymoma. One was cured, with a follow-up of 70 months, and one died while on therapy. Analysis of the histological features and the immunoperoxidase staining displays the complexity of pediatric thymomas and the inability to prognosticate the outcome, respectively.