A rare case of collecting duct renal cell carcinoma

Collecting duct carcinoma is an exceptionally rare and aggressive form of renal cell carcinoma (RCC), representing between 0.4 and 1.8% of RCC cases. The most commonly affected demographic are young African-American males. Here, we present a rare case of collecting duct RCC in a 22 year-old Caucasian female with final pathological staging of pT1aN1 who underwent robot-assisted right radical nephrectomy, with peri-hilar and para-aortic lymph node dissection. Given her node-positivity, adjunctive treatment is discussed.

A rare case of ductal variant multilocular prostatic cystadenocarcinoma invading the rectum

Prostate papillary and cribriform ductal prostatic adenocarcinoma is a rare malignancy infrequently reported in the literature. We describe a case of rectally invasive prostate cystic adenocarcinoma and surgical extirpative management not requiring fecal or urinary diversion.

Conductive hybrid carbon nanotube (CNT)–polythiophene coatings for innovative auditory neuron-multi-electrode array interfacing

Surface modification of platinum electrodes to improve neuron-electrode interface and electrode conductive properties in cochlear implants.

[Prosthetic hip infection due to Listeria monocytogenes: review of the literature and case report]

With the ageing of the population, articular prosthetic replacements are becoming more and more frequent. One of the most feared complications is prosthetic infection, mostly due to bacteria of the cutaneous flora. Listeria monocytogenes is rarely the cause. This paper describes the management of a hip prosthetic infection due to Listeria monocytogenes. The patient was cured with antimicrobial therapy and a two-stage exchange. This case report creates an opportunity to review the literature in the aim of determining the risk factors and the optimal care.

Extra-axial cavernous hemangioma: two case reports

Two patients with extra-axial cavernous hemangioma who presented with headache and oculovisual disturbances were investigated with computed tomography and magnetic resonance imaging. The lesions masqueraded as basal meningioma, but this diagnosis was not supported by magnetic resonance spectroscopy in one patient. Cerebral angiography with embolization was indicated in one patient, but embolization was not justified in the other. Both patients underwent a pterional craniotomy. The lesions were extradural and highly vascular, necessitating excessive transfusion in one patient in whom gross total resection was achieved, and precluding satisfactory removal in the other. There was no mortality. Transient ophthalmoplegia, the only complication in one patient, was due to surgical manipulation of the cavernous sinus; it resolved progressively over 3 months. Extra-axial skull base cavernous hemangiomas are distinct entities with clinical and radiological characteristics that differ from those of intraparenchymal cavernous malformations. They can mimic meningiomas or pituitary tumors. In some cases, magnetic resonance spectroscopy may narrow the differential diagnoses. Surgical resection remains the treatment of choice, facilitated by preoperative embolization to reduce intraoperative bleeding and by the application of the principles of skull base surgery. Fractionated radiotherapy is an alternative in partial or difficult resections and in high-risk and elderly patients.

East pacific rise: hot springs and geophysical experiments

Hydrothermal vents jetting out water at 380 degrees +/- 30 degrees C have been discovered on the axis of the East Pacific Rise. The hottest waters issue from mineralized chimneys and are blackened by sulfide precipitates. These hydrothermal springs are the sites of actively forming massive sulfide mineral deposits. Cooler springs are clear to milky and support exotic benthic communities of giant tube worms, clams, and crabs similar to those found at the Galápagos spreading center. Four prototype geophysical experiments were successfully conducted in and near the vent area: seismic refraction measurements with both source (thumper) and receivers on the sea floor, on-bottom gravity measurements, in situ magnetic gradiometer measurements from the submersible Alvin over a sea-floor magnetic reversal boundary, and an active electrical sounding experiment. These high-resolution determinations of crustal properties along the spreading center were made to gain knowledge of the source of new oceanic crust and marine magnetic anomalies, the nature of the axial magma chamber, and the depth of hydrothermal circulation.

Correlation between magnetic resonance imaging and histopathologic grades in Rasmussen syndrome

The aim of this study was to investigate the correlation between magnetic resonance imaging (MRI) and histopathologic findings in Rasmussen syndrome. Serial MRIs were obtained for five patients who had histologically proven Rasmussen syndrome. The histopathologic grades of the lesions were subdivided into phases: active 1-3, resolving 1-3, and chronic inflammatory. The images were then correlated with histopathologic findings. Neuropathologic findings in the central areas on MRI demonstrated only the chronic and resolving grades, but active inflammatory abnormalities were present not only at the margins of the lesions, but also in areas of subtle signal abnormality on MRI. Atrophic areas on MRI exhibited all grades of histopathologic abnormalities, but chronic and resolving grades were predominant. Seizure duration of less than 6 months was associated with very active grades, duration of 1-2 years with variable grades, and duration greater than 6 years with chronic and resolving grades only. The MRI images correlated highly with histopathologic analysis. These findings suggest that the lesions initially arise from one site in the brain, and so support the centrifugal spreading theory of this disease. Findings also suggest that the margin rather than the center of the MRI abnormality may be the most ideal site for biopsy.

A dual band wireless power and FSK data telemetry for biomedical implants

A dual-link coil arrangement and a novel digital frequency-shift keying (FSK) demodulator are presented. The primary application of this system is for inductively powered biomedical implants. The implant is provided with data and power via two separate links. Two sets of coils are used in an arrangement such that the magnetic interference between the two pairs is minimized. The demodulator circuitry presented relies solely on delaying elements, utilizing a delayed digital FSK signal to sample the original digital FSK signal. A synchronized clock can be derived from the FSK signals alone, however, by utilizing the power signal to obtain a synchronized clock, a higher data rate and a decrease in complexity of the receiver circuitry can be achieved. The system was implemented on the bench and experimentally tested at a data rate of 2.083 Mbps with zero bit error rate while receiving a 4.17/6.25 MHz FSK carrier signal synchronized with 2.083 MHz clock derived from the power carrier. The power link was set to provide 58mW.

Unusual polypoid laryngeal myxoma

Laryngeal polyps, known as vocal cord polyps, are often benign, reactive, polypoid, squamous mucosa with subepithelial hyalinization and edematous stroma. Rarely, a benign mesenchymal myxoma occurring in the vocal cord will present as a polyp. It may have a local recurrence due to inadequate excision and result in airway obstruction. We report a case of a 46-year-old male who had a history of smoking and complained of hoarseness. A polypoid vocal cord mass was removed and the pathologic finding was a benign myxoma. To assure complete excision of the lesion, one should be aware that this rare entity may involve a laryngeal location.

ACTH-producing pituitary cancer: experience at the King Faisal Specialist Hospital & Research Centre

Pituitary gland is an uncommon site of a primary cancer. Of more than 600 cases of pituitary tumors seen at the KFSH&RC between 1975 to 1998 only 3 patients had primary pituitary cancer. We have previously reported a case of pituitary fibrosarcoma arising as a rare complication of external radiotherapy (ERT) for GH-secreting pituitary adenoma (PA) [1]. We report now 2 cases of ACTH-producing primary pituitary carcinoma (ACTH-PPC); their follow-up data provide information on the natural history of this cancer. Patient #1; a 46 year old lady with Cushing's disease (CD) presented with an enlarged right cervical lymph node (LN) 2 years after having undergone a partial hypophysectomy through transsphenoidal surgery (PHYPX/TSS) and ERT for an invasive pituitary tumor. Patient #2; a 26 year old man presented with CD and underwent bilateral adrenalectomy (ADx) and pituitary ERT. Thirty-nine months later he developed Nelson's syndrome and a PHYPX/TSS was performed. Incidentally discovered hepatic metastases in this patient and an excisional biopsy of the LN in patient #1 showed histological features very similar to the pituitary tumor, and they stained strongly positive for ACTH. Perinuclear spherical hyalinized cytoplasmic inclusions were seen in the LN biopsy that corresponded to bundles of type 1 microfilaments (specific for pituitary ACTH-producing cells) seen by electron microscopy. A whole body 18-Fluoro-2-Deoxy-D-Glucose positron emission (FDG-PET) scanning, showed an intense uptake in the neck mass. A trial of octreotide did not change the exceedingly high levels of ACTH in patient #2, further supporting the diagnosis of ACTH-PPC. The clinical course of 102 months prior to his demise showed continued progression of the primary and the metastatic tumor. Patient #1, is alive at 15 months follow-up; hypercortisolemia is controlled using ketoconazole. ACTH-PPC should be entertained in a patient with CD presenting with persistent cervical lymphadenopathy. The clinical course in our patients suggests that the emergence of PC may involve a proliferative continuum from a pre-existing PA to an invasive tumor, culminating in a carcinoma. Adjunctive events such as ERT/ADx may predispose to the evolution of PC in genetically susceptible individuals. Because ERT is an effective treatment for PA its use will continue; it is important to be aware of the possible complication of primary pituitary carcinoma.

Retinoblastoma as a congenital primary intracranial tumor

This report describes a rare case of retinoblastoma presenting as a congenital primary intracranial tumor. A 7-day-old infant presented with generalized seizures. He had a family history of retinoblastoma. Computed tomography of the brain revealed a midline suprasellar tumor without evidence of retinal tumors. Subtotal resection of the tumor was performed. Histopathologic findings were diagnostic of retinoblastoma. The patient sustained profound ischemic brain damage and was not given definitive further therapy. He died days after the diagnosis was made. Retinoblastoma can present as an isolated ectopic intracranial tumor without associated retinal tumors.

Miyoshi myopathy in Saudi Arabia: clinical, electrophysiological, histopathological and radiological features

Miyoshi myopathy (MM) is a rare autosomal recessive distal myopathy linked to chromosome 2p12-14 that has not been described in Saudi Arabia. A Saudi family with five siblings aged 3-25 years, an unrelated 18-year-old woman and a 40-year-old man with MM were identified. All patients underwent a neurological examination, serum chemistry, electromyography and MRI of the legs. Four patients underwent a muscle biopsy that was processed for routine enzyme histochemistry and immunocytochemical analyses for dystrophin and adhalin (alpha-sarcoglycan). The two sporadic and two familial cases showed classic findings of MM, including early adult onset, preferential involvement of gastrocnemius muscles, markedly elevated serum creatine kinase levels and dystrophic-appearing muscle without vacuoles. Magnetic resonance imaging revealed selective involvement of the posterior compartment muscles and myoedema by STIR sequences. The remaining three familial cases had elevated serum creatine kinase levels and two also had early myopathic findings by EMG suggestive of MM.

The 39-kilodalton outer membrane protein of Proteus mirabilis is an OmpA protein and mitogen for murine B lymphocytes

Partial amino acid sequence analysis of a major outer membrane protein of Proteus mirabilis (39-kDa protein) indicates that it is an OmpA protein. The mitogenic activities of the 39-kDa protein for murine lymphocytes were also investigated with T lymphocytes isolated by passing spleen cells over columns of nylon wool fiber and B lymphocytes obtained by treating spleen cells with monoclonal antibodies to Thy1 plus complement. The 39-kDa protein showed little activity in stimulating T cells to proliferate but was strongly mitogenic for B cells.

Emergency flexible fiberoptic nasotracheal intubation: a report of 60 cases

We describe our experience with 60 consecutive intubations using flexible fiberoptic nasotracheal technique in the emergency setting. Fifty-seven of the procedures were carried out by two emergency physicians initially trained on intubation manikins. A learning curve is constructed demonstrating that time to intubation is decreased after nine or ten intubations. Complications are reviewed. Bleeding occurred in 22% of patients; the technique failed in 13%. Failure to intubate with fiberoptic technique was associated with specific problems such as bleeding, tumor, or agitation. Our results demonstrate both the limitations and special use of flexible fiberoptic technique.