Factitious insulinoma

A 32-year-old woman was admitted with signs of recurrent hypoglycaemia. Within 72 hours hypoglycaemia was successfully provoked by prolonged fasting. Also, blood samples demonstrated high levels of serum insulin and C-peptide and the insulin-glucose ratio was abnormally high. An insulinoma was strongly suspected. However, extensive imaging displayed no tumour in the pancreas. The patient also had extensive psychological and social problems. The psychiatrist suggested a factitious disorder. High serum concentrations of insulin and C-peptide in combination with the psychiatric disorder led to the suspicion of abuse of sulfonylurea derivatives by the patient. This was confirmed by toxicological screening. A patient with unexplained hypoglycaemia, especially if an insulinoma cannot be detected, should be suspected of abusing sulfonylurea derivatives.     

Whole-body [18F]FDG PET in the management of metastatic brain tumours

BACKGROUND: To determine its roles in the diagnosis and the systemic evaluation of metastatic brain tumours, whole-body positron emission tomography (PET) using [18F]FDG was performed in 20 consecutive patients. METHODS: All patients were thought to be suffering or needing to be differentiated from metastatic brain tumours. Nine patients had multiple brain lesions; six were older and showed a rim-enhancing lesion with surrounding oedema; seven had homogeneously enhancing periventricular lesion(s) on computed tomography (CT) and/or magnetic resonance (MR) imaging, thought to be central nervous system lymphomas. Two patients had skull mass(es) and two patients had a solid mass suspected to be, respectively, a haemorrhagic metastasis and a metastatic malignant melanoma. All of them received whole-body [18F]FDG PET and conventional systemic work-up for metastasis in order to compare the results of the two methods. RESULTS: Metastatic brain tumours were diagnosed on whole-body [18F]FDG PET in eleven patients who had extracranial and intracranial hypermetabolic lesions. In nine of these, a conventional work-up also detected primary lesions which on whole-body [18F]FDG PET were seen to be hypermetabolic foci. Systemic lymph node metastases were detected by whole-body [18F]FDG PET only in two patients and histological diagnosis was possible by biopsy of lymph nodes rather than of brain lesions. In the remaining nine patients who had only intracranial hypermetabolic foci, histological diagnosis was made by craniotomy or stereotactic biopsy. It was confirmed that seven of nine patients were suffering from a primary brain tumour and two from metastatic carcinoma. None of the nine showed evidence of systemic cancer on conventional work-up. Histological diagnoses of the primary brain tumours were four cases of primary central nervous system lymphoma and one each of multifocal glioblastoma, Ewing's sarcoma, and cavernous angioma. Patients felt no discomfort during the whole-body [18F]FDG PET procedure and there were no complications. The false negative rate in [18F]FDG PET and in conventional work-up was 15.4% and 30.7% respectively. There were no false positives on either [18F]FDG PET or conventional work-up. CONCLUSION: It is suggested that whole-body [18F]FDG PET is a safe, reliable, and convenient method for the diagnosis and systemic evaluation of patients thought to be suffering or needing to be differentiated from a metastatic brain tumour.     

Calretinin and calbindin D28K immunoreactivity in the superficial layers of the rabbit superior colliculus

Calretinin and calbindin D28K were localized in the superficial layers of rabbit superior colliculus (SC). Calretinin and calbindin D28K-immunoreactive (-IR) neurons were concentrated in the upper superficial gray layer. Calretinin-IR fibers were found in the optic layer. The majority of calretinin-IR cells were small- to medium-sized vertical fusiform neurons and neurons with round or stellate-shaped somas with small varicose dendrites. The morphology of calbindin D28 K-IR neurons was different from that of calretinin neurons. Anti-calbindin D28K-IR neurons usually had fusiform cell bodies and a thick primary dendrite with small branches forming a dendritic bouquet. Two-color immunofluorescence revealed that no cells expressed both proteins. Following unilateral enucleation a marked reduction of calretinin-IR fibers in the contralateral side to the enucleation was found. Enucleation appeared to have no effect on the cell bodies labeled with either protein. The results suggest the anti-calretinin immunoreactivity in the superficial layer of rabbit SC contrasts starkly with that of other animals.     

Fundamental cryobiology of selected African mammalian spermatozoa and its role in biodiversity preservation through the development of genome resource banking

Fundamental cryobiological characteristics of spermatozoa from threatened or endangered species must be determined for successful cryopreservation techniques to be established. In this study, spermatozoa from four diverse species, impala (Aepyceros melampus), wart hog (Phacochoerus aethiopicus), elephant (Loxodonta africana), and lion (Panthera leo), were collected by electroejaculation or epididymal aspiration. Spermatozoal plasma membrane permeability to water (hydraulic conductivity, Lp) and the osmotically inactive fraction of the sperm cell (Vb) were determined from each species. Changes in cell volume were measured over time using an electronic particle counter. A Kedem-Katchalsky membrane transport model was used to theoretically characterize the data to determine Lp and Vb for each species. In addition to determining plasma membrane characteristics, spermatozoa were also studied to determine their sensitivity to low temperatures and to permeating cryoprotectant solutes. Cells maintained at room temperature (20-22 degrees C) were slowly or rapidly exposed to cold temperatures (1-4 degrees C), and percent motility was estimated to determine the sensitivity of the cells to cooling. Spermatozoa were also in media containing 1 M glycerol, dimethyl sulfoxide or ethylene glycol, and percent motility was measured at 15, 30 and 60 min intervals to determine the sensitivity of the cells to the cryoprotectant agent over time. Results indicate that sperm motility is significantly effected by decreased temperatures and the presence of cryoprotectant agents.     

Development of an automated turbidimetric immunoassay for quantification of bovine serum immunoglobulin G

OBJECTIVE: To develop an automated turbidimetric immunoassay (TIA) for measurement of bovine IgG. SAMPLE POPULATION: 24 bovine serum samples. PROCEDURE: IgG concentration was determined by use of the TIA, and results were compared with those of the radial immunodiffusion (RID) method. Variables were determined, using commercially available reagents and a clinical biochemical analyzer. For the TIA, polyclonal goat anti-bovine IgG (Fc specific) serum, bovine IgG calibrator serum, and polyethylene glycol reaction buffer were used. Sample concentrations were determined by the instrument, using the linear regression method of least squares. The accuracy of this assay was validated by referencing to a purified bovine IgG standard and by recovery of control standards. Parallelism was documented by assay linearity and serial sample dilution linearity. Interference resulting from hemolyzed samples was examined. RESULTS: The TIA method correlated positively (r = 0.9957) and significantly (P < 0.05) with the RID method, yielding a regression equation with slope of 0.78708 and y-intercept of 1.02102. Bias attributable to hemolysis was not observed. CONCLUSIONS: The TIA method is automated, accurate, and precise for bovine serum IgG quantification. CLINICAL RELEVANCE: This assay provides sample results in approximately 10 minutes and may be used as an alternative to the manual RID method.     

Regulation of interleukin-8 binding and function by heparin and alpha2-macroglobulin

The effect of radiation on speech and swallowing function was assessed for 18 patients surgically treated for oral and oropharyngeal cancer. Nine patients received surgical intervention and postoperative radiation therapy, and nine received surgery only. Patients were matched regarding percentage of oral tongue resected, percentage of tongue base resected, locus of resection, and method of reconstruction. Speech and swallowing function was assessed before and at 1, 3, 6, and 12 months after surgery following a standardized protocol. Speech tasks included an audio recording of a brief conversation and of a standard articulation test; swallowing function was examined with videofluoroscopy. Statistical testing indicated that overall speech function did not differ between the irradiated and nonirradiated patients. Irradiated patients had significantly reduced oral and pharyngeal swallowing performance, specifically, longer oral transit times on paste boluses, lower oropharyngeal swallow efficiency, increased pharyngeal residue, and reduced cricopharyngeal opening duration. Impaired function may be the result of radiation effects such as edema, fibrosis, and reduced salivary flow. Increased use of tongue range-of-motion exercises during and after radiation treatment may reduce the formation of fibrotic tissue in the oral cavity and may improve pharyngeal clearance by maintaining adequate tongue base-to-pharyngeal wall contact.