Biomedical subjects

J F Madden

Publications and source records attributed to J F Madden.

28 records · Page 2Linked to original sources

PubMed1995

Cerebral phaeohyphomycosis complicated with brain abscess: a case report.

Cerebral phaeohyphomycosis is used to describe the rare clinical syndrome of cerebral infection caused by dematiaceous (i.e. pigmented olivaceous-brown) fungi. It usually presents as brain abscess. In view of the rarity of this fungal infection and its clinical importance, we report a case of cerebral phaeohyphomycosis caused by Xylohypha bantiana. The patient presented with a seizure attack. The MRI study revealed a ring-enhancing lesion with marked perifocal edema in right high frontoparietal junction of the brain. He underwent an initial craniotomy for removal of the lesion and a second craniotomy for recurrence of the lesion 3 months later. The diagnosis was based on successful cultivation of X. bantiana from the surgical specimen and on histopathology. The patient received antifungal drug therapy of 5-flucytosine and itraconazole. He has done well without any symptoms. We think complete surgical removal of the brain abscess combined with antifungal drug therapy is the best management for this rare fungal disease.

Brain Abscess↗

PubMed1989

Resonance Raman studies of Escherichia coli sulfite reductase hemoprotein. 1. Siroheme vibrational modes.

Resonance Raman (RR) spectra are reported for the hemoprotein subunit (SiR-HP) of Escherichia coli NADPH-sulfite reductase (EC 1.8.1.2) in various ligation and redox states. Comparison of the RR spectra of extracted siroheme and the mu-oxo FeIII dimer of octaethylisobacteriochlorin with those of mu-oxo FeIII octaethylchlorin dimer and mu-oxo FeIII octaethylporphyrin dimer demonstrates that many siroheme bands can be correlated with established porphyrin skeletal modes. Depolarization measurements are a powerful tool in this correlation, since the 45 degrees rotation of the C2 symmetry axis of the isobacteriochlorin ring relative to the chlorin system results in reversal of the polarization properties (polarized vs anomalously polarized) of bands correlating with B1g and B2g modes of porphyrin. Various SiR-HP adducts (CO, NO, CN-, SO3(2-] show upshifted high-frequency bands, characteristic of the low-spin state and consistent with the expected core size sensitivity of the skeletal modes. Fully reduced unliganded SiR-HP (both siroheme and Fe4S4 cluster reduced) in liquid solution displays RR features comparable to those of high-spin ferrous porphyrins; on freezing, the RR spectrum changes, reflecting an apparent mixture of siroheme spin states. At intermediate reduction levels in solution a RR species is observed whose high-frequency bands are upshifted relative to oxidized and fully reduced SiR-HP. This spectrum, thought to arise from the "one-electron" state of SiR-HP (siroheme reduced, cluster oxidized), may be due to S = 1 FeII siroheme.

Binding Sites↗

PubMed1989

Resonance Raman studies of Escherichia coli sulfite reductase hemoprotein. 2. Fe4S4 cluster vibrational modes.

Resonance Raman (RR) spectra from the hemoprotein subunit of Escherichia coli sulfite reductase (SiR-HP) are examined in the low-frequency (200-500 cm-1) region where Fe-S stretching modes are expected. In spectra obtained with excitation in the siroheme Soret or Q bands, this region is dominated by siroheme modes. Modes assignable to the Fe4S4 cluster are selectively enhanced, however, with excitation at 488.0 or 457.9 nm. The assignments are confirmed by observation of the expected frequency shifts in SiR-HP extracted from E. coli grown on 34S-labeled sulfate. The mode frequencies and isotopic shifts resemble those seen in RR spectra of other Fe4S4 proteins and analogues, but the breathing mode of the cluster at 342 cm-1 is higher than that observed in the other species. Spectra of various ligand complexes of SiR-HP reveal only slight sensitivity of the cluster terminal ligand modes to the presence of exogenous heme ligands, at variance with a model of ligand binding in a bridged mode between heme and cluster. Close examination of RR spectra obtained with siroheme Soret-band excitation reveals additional 34S-sensitive features at 352 and 393 cm-1. These may be attributed to a bridging thiolate ligand.

Escherichia coli↗

PubMed1989

Resonance Raman studies of Escherichia coli sulfite reductase hemoprotein. 3. Bound ligand vibrational modes.

The vibrations of the bound diatomic heme ligands CO, CN-, and NO are investigated by resonance Raman spectroscopy in various redox states of Escherichia coli sulfite reductase hemoprotein, and assignments are generated by use of isotopically labeled ligands. For the fully reduced CO complex (ferrous siroheme, reduced Fe4S4 cluster) at room temperature, nu CO is observed at 1904 cm-1, shifting to 1920 cm-1 upon oxidation of the cluster. The corresponding delta FeCO modes are identified at 574 and 566 cm-1, respectively, by virtue of the zigzag pattern of their isotopic shifts. In frozen solution, two species are observed for the cluster-oxidized state, with nu CO at 1910 and 1936 cm-1 and nu FeC at 532 and 504 cm-1, respectively; nu FeC for the fully reduced species is identified at 526 cm-1 in the frozen state. For the ferrous siroheme-NO complex (cluster oxidized), nu NO is identified at 1555 cm-1 in frozen solution and a low-frequency mode is identified at 558 cm-1; this stretching mode is significantly lower than that observed in Mb-NO. For the ferric siroheme cyanide complexes evidence of two ligand-bonding forms is observed, with modes at 451/390 and 451/352 cm-1; they are distinguished by a reversal of the isotopic shift patterns of the upper and lower modes and could arise from a linear and a bent Fe-C unit, respectively. For the ferrous siroheme cyanide complex isotope-sensitive modes observed at 495 and 452 cm-1 are assigned to the FeCN- bending and FeC stretching vibrations, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Carbon Isotopes↗

PubMed1984

Comparison of serotonin uptake by dense bodies inside and outside human platelets.

A technique has been developed for quantitating the absolute number of dense bodies present in solution following isolation from human platelets. The amount of [3H]-5HT accumulated per dense body was measured following either sonication alone or sonication plus isolation utilizing a Metrizamide density gradient; the dense bodies in each case were washed and resuspended in sodium or potassium-rich buffer. Uptake per dense body following removal from the cell was less than 10% of the amount of uptake per dense body by intact platelets. It thus seems possible that residence of dense bodies inside intact platelets is required for 5HT transport into dense bodies to proceed at a maximal rate.

Blood Platelets↗

PubMedDate not supplied

Dynamic contrast-enhanced MR imaging assessment of vascularized free fibular grafts.

Magnetic resonance (MR) imaging may be a noninvasive method for assessing perfusion of vascularized bone grafts placed for treatment of avascular necrosis. One proximal femur of seven beagles was devascularized, with insertion of a vascularized fibular graft. MR imaging at 1 week (seven dogs) and 6 weeks (five dogs) after surgery included pre- and postcontrast spin-echo sequences, unenhanced two-dimensional time-of-flight (TOF) vascular imaging, and dynamic gradient-echo imaging during infusion of gadolinium. Relative signal intensity values of selected regions obtained from the dynamic gradient-echo images were plotted as percent enhancement versus time. In the operated hip, MR imaging did not show enhancement in six of seven femoral heads and greater trochanters at 1 week after surgery, with similar results after 6 weeks. MR imaging of fibular grafts 6 weeks after surgery showed an initial rapid increase in enhancement and a subsequent slower increase in five of five dogs, although no enhancement was seen in six of seven dogs at 1 week. These findings contrasted with a rapid initial increase in enhancement followed by slow decline in non-operated hips. Two-dimensional TOF imaging did not show the vascular pedicle of the graft in any dog. Findings of radionuclide bone scanning performed 1 week after surgery were consistent with devascularization of the operated femur and fibular graft. However, tetracycline distribution and histologic findings confirmed the viability of five of five grafts within the devascularized femurs 6 weeks after surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMedDate not supplied

The range of medication storage temperatures in aeromedical emergency medical services.

OBJECTIVES: The United States Pharmacopoeia (USP) recommends that medication storage temperatures should be maintained between 15 degrees C and 30 degrees C (59 degrees F to 86 degrees F). Concerns have been raised that storage temperatures in EMS may deviate from this optimal range, predisposing drugs to degradation. This study was conducted to determine whether temperatures inside the drug box carried by paramedics aboard a helicopter remained within the range. METHODS: The Aviation Section, with a paramedic on board, utilizes two helicopters and conducts approximately 80 patient care flights per month. A dual-display indoor/outdoor thermometer with memory was used to measure the highest and lowest temperatures during each shift. The thermometer was kept with medications in a nylon drug bag, which remained on the helicopter except when needed for patient care. Ambient temperature measurements at the location of the helicopter base were obtained from the National Climatic Data Center. Temperature ranges were recorded during day shift (8 AM to 4 PM) and night shift (4 PM to 12 AM) during the winter from December 1, 1995, to March 13, 1996, and summer from June 17, 1996, to September 14, 1996. Statistical analysis was performed using chi-square and the Bonferroni-adjusted t-test. RESULTS: Compared with the winter day period, the winter night period had lower minimum (13.2 degrees C vs 14.7 degrees C, p = 0.003) and maximum (20.3 degrees C vs 21.2 degrees C, p = 0.02) temperatures. Both were below the USP minimum. The summer day period had higher maximum temperatures than the summer night period (31.2 degrees C vs 27.6 degrees C, p = 5 x 10(-9)). The mean daytime summer maximum exceeded the USP upper limit. Storage temperatures outside of the USP range were observed during 49% of winter days, 62% of winter nights, 56% of summer days, and 27% of summer nights. There was a significant tendency for summer days (p = 8 x 10(-8)) and winter nights (p = 0.009) to be outside of the acceptable range. There was moderate correlation between ambient and drug box temperatures (r2 = 0.49). CONCLUSIONS: Medications stored aboard an EMS helicopter are exposed to extremes of temperature, even inside a drug bag. Measures are needed to attenuate storage temperature fluctuations aboard aeromedical helicopters.

Air Ambulances↗

PubMedDate not supplied

Closed reduction of a traumatically dislocated testicle.

Traumatic testicular dislocation is an uncommon event, with fewer than 60 cases having been reported in literature. It is imperative that the emergency physician be aware of the possibility of testicular dislocations following perineal trauma and either seek emergent urologic consultation or attempt relocation of the testicle immediately. Testicular dislocation (following a motorcycle crash) that was successfully managed by closed reduction in the emergency department (ED) is presented. Following a benign course during subsequent observation, the patient was released with close urologic follow-up.

Accidents, Traffic↗

PubMedDate not supplied

Features of benign granular cell tumor on fine needle aspiration.

OBJECTIVE: To describe the cytomorphologic features of benign granular cell tumor (GCT) on fine needle aspiration (FNA) biopsy and discuss the differential diagnosis. STUDY DESIGN: We reviewed three fine needle aspirates of surgically confirmed benign GCT. Immunocytochemical staining for S-100 was performed on the aspirate smear in one case. RESULTS: Two GCT were thigh lesions, where lipoma and fibromatosis were the leading clinical diagnosis, and the third was a breast mass clinically suspected to be a fibroadenoma. All FNA specimens were highly cellular and composed of fairly uniform cells with eccentric, round-to-slightly oval nuclei and abundant, finely granular cytoplasm. The cells were fragile, with stripped nuclei in a background of finely granular material. Occasional cells with nuclear pleomorphism and small-but-conspicuous nucleoli were identified. There was no evidence of necrosis or mitotic activity. Rare intranuclear cytoplasmic inclusions were identified in two cases. The granular cells were immunoreactive for S-100 in the case studied. CONCLUSION: Benign GCT has a distinctive cytomorphologic appearance that permits its diagnosis on FNA. High cellularity, occasional cells with nuclear pleomorphism and prominent nucleoli are features that can be present in benign GCT. Mitotic figures and necrosis should be identified before a diagnosis of malignancy is rendered.

Adult↗

PubMedDate not supplied

Meningioangiomatosis: CT and MR findings.

Meningioangiomatosis (MA) is a rare hamartomatous lesion of the cerebral cortex; to date only 18 cases with imaging findings have been reported in the English literature. The origin of MA is probably malformative, with possible association with neurofibromatosis. These lesions frequently cause seizures in young patients. We report two new cases seen at our institution and present their CT and MR findings clearly illustrating MA cortex infiltration. Gd-DTPA used in one of the two cases failed to cause enhancement.

Child↗