Emergence of Multidrug Resistant Extended-Spectrum ß-Lactamase Producing Eshcherichia coli Associated With Urinary Tract Infections in Bangladesh.

The incidence of infections due to extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli has been increased dramatically in recent years. Treatment is difficult because of frequent multidrug resistance. To identify the sensitivity of commonly used antibiotics, 36 ESBL producing E. coli strains were isolated from young adult female patients in a govt. medical college hospital in Bangladesh. The samples were studied for antimicrobial sensitivity against nine (9) commonly used antibiotics namely ampicillin (amp), trimethoprim-sulfomethoxazole (tms), tetracycline (tet), ciprofloxacin (cip), mecillinum (mel), ceftriaxone (cef), nalidixic acid (nal), Azithromycin (azm) and Chloramphenicol (chl) and the MIC values were determined by agar dilution method. Overall, 72% of the strains were multidrug resistant (MDR) i.e. resistant to two or more drugs. Among 36 strains, 14 isolates were initially found to be resistant against third generation cephalosporin, ceftriaxone. Those were subjected to the test for production of ESBL (Extended Spectrum ß-Lactamase) and 7 showed positive results.

MR imaging of intrahepatic cholangiocarcinoma: use of ferumoxides for lesion localization and extension.

OBJECTIVE: The purpose of this study was to evaluate the use of ferumoxides in the visualization and localization of intrahepatic cholangiocarcinoma. CONCLUSION: The contrast-to-noise ratio of cholangiocarcinoma compared with that of the adjacent liver significantly (p < 0.03) improves after ferumoxides administration. Ferumoxides-enhanced MR imaging is a useful technique for the visualization and localization of intrahepatic cholangiocarcinoma.

MR imaging in the evaluation of hepatic metastases.

Optimal detection of focal hepatic lesions in patients with metastases can alter patient management and result in significant cost savings by reducing the number of unnecessary laparotomies for unresectable disease. Liver-specific MR imaging contrast agents (reticuloendothelial and hepatobiliary agents) offer greater lesion-to-liver contrast than the conventional extracellular fluid space MR imaging contrast agents (gadolinium chelates), which have a nonspecific distribution. For the detection of hepatic metastases, although the work of Seneterre et al suggests that the accuracy of ferumoxide-enhanced MR imaging is equivalent to that of CTAP, other studies find CTAP to be superior. Comparisons of reticuloendothelial agents and hepatobiliary agents for imaging liver metastases are lacking in the literature. Further studies comparing MR imaging enhanced with liver-specific contrast agents to CTAP are needed to determine if hepatic MR imaging can replace CTAP for the preoperative evaluation of hepatic metastases. For the characterization of focal liver lesions, MnDPDP and ferumoxides have been added to the small list of FDA-approved contrast agents, and both can help to increase diagnostic specificity. Two of the hepatobiliary agents which are not yet approved, Gd-BOPTA and Gd-EOB-DTPA, have the potential of characterizing liver lesions during dynamic contrast enhancement (similar to Gd-DTPA) and during the hepatocyte phase (similar to MnDPDP), and may increase the detection of focal liver lesions.

Color and power Doppler sonography of liver hemangiomas: a dream unfulfilled?

PURPOSE: The aim of this study was to determine whether color Doppler or power Doppler sonography can aid in the diagnosis of hepatic cavernous hemangiomas. METHODS: We imaged 25 hepatic cavernous hemangiomas in 17 patients with gray-scale, color Doppler, and power Doppler sonography. Five malignant lesions were also imaged in the same manner for reference. Hemangiomas had been previously diagnosed by biopsy in 8 patients (15 lesions) and by CT, MRI, and/or tagged red blood cell scanning in 9 patients (10 lesions). RESULTS: Of the 25 hemangiomas, color or power Doppler imaging showed no internal blood flow in 23. Of these 23 lesions, 11 showed a peripheral flow pattern believed to represent flow in displaced blood vessels. This pattern was better visualized with power Doppler imaging in 3 lesions and equally well visualized with color and power Doppler imaging in 8 lesions. Two hemangiomas that had unusual central fibrosis with large vessels in 1 patient showed diffusely increased blood flow on power Doppler study. All 5 malignant lesions showed flow in peripheral vessels, and 1 showed internal vascularity as well. CONCLUSIONS: Neither color nor power Doppler imaging improved the capability of sonography for making a specific diagnosis of benign hepatic cavernous hemangioma.

Difference images calculated from ictal and interictal technetium-99m-HMPAO SPECT scans of epilepsy.

UNLABELLED: Image processing techniques were applied to SPECT brain images to aid in the localization of epileptic foci. METHODS: Ictal and interictal cerebral perfusion SPECT images were acquired from 12 epilepsy patients (6 temporal, 6 extratemporal) after injection of 20 mCi 99mTc-HMPAO. Each ictal scan was registered to the same patient's interictal scan. Normalization of the three-dimensional data was applied to account for global percent brain uptake and total injected activity. After registration, normalization and subtraction of the SPECT images and functional difference images were computed. Difference images were calculated, which give a quantitative measure of perfusion alterations during ictus. The resulting difference images were also registered with each patient's MRI scan which permits localization of perfusion changes onto anatomical structures. RESULTS: Areas in the brain where significant perfusion increases occur correlate with areas confirmed to be seizure foci. Four of the six patients with known temporal lobe seizure foci exhibited significant perfusion increases on the difference images. These areas demonstrate a percent increase of perfusion larger than 40%. For the extratemporal seizure patients, four of the four confirmed seizure sites were diagnosed with difference images. Results on the remaining two patients were inconclusive. CONCLUSION: When compared to side-by-side visual interpretation of the ictal and interictal SPECT images, registration of SPECT and MR images together with calculated difference maps greatly enhances the ability to localize epileptic seizure foci. This offers the potential to locate epileptic seizure foci using a noninvasive, inexpensive imaging procedure and data processing algorithm.

Therapeutic approach to hypertension in the elderly.

Hypertension is an important risk factor for cardiovascular disease in the elderly. This article addresses the factors that increasingly influence hypertension as age increases. In addition, the initial therapeutic approach to the elderly hypertensive patient should generally consist of a reduction in salt and caloric intake and increased exercise. Drug therapy should be initiated with lower doses of medication with special concern about orthostatic hypotension. The drug regimen should be made as simple as possible and be carefully explained to the patient. With these considerations in mind, hypertension in the geriatric patient can be effectively managed.

Muramyl peptide/serotonin receptors in brain-derived preparations.

Certain peptidoglycans (muramyl peptides), components of bacterial cell walls, and the monoaminergic neurotransmitter serotonin, profoundly modulate some activities of mammalian immune and nervous systems. We previously described the interaction of these compounds at receptors on macrophages. This report concerns specific binding sites for muramyl peptide in preparations of brain tissue, interaction between muramyl peptide and serotonin in binding to glial-derived cells, and the ability of both muramyl peptide and serotonin to induce release of interleukin-1-like activity from these cells. Specific binding sites for muramyl peptides in the low-nanomolar concentration range were found on subcellular fractions of fresh rat brain preparations, e.g., from diencephalon, and C6 glioma cells. This binding was saturable, reversible, stereospecific, and varied with brain region. In addition, muramyl peptide blocked the specific component of serotonin binding to glioma cells, while leaving the nonspecific binding component unaffected. Interleukin-1 has previously been shown to be released by macrophages in response to muramyl peptide. We found that low-nanomolar concentrations of either muramyl peptide or serotonin rapidly induced release of interleukin-1-like activity from a glial cell line. Thus, the pyrogenic and sleep-promoting effects of muramyl peptide may be mediated at least in part by release of interleukin-1 in the brain that follows binding to muramyl peptide/serotonin receptors on glial cells.

Atrial natriuretic peptide attenuates the reflex sympathetic responses to lower body negative pressure.

The authors studied the effect of intravenous infusion of atrial natriuretic peptide (ANP) on the plasma catecholamine and forearm vasoconstrictor responses to cardiopulmonary baroreflex deactivation in six normal, male volunteers in order to determine whether ANP influences reflex forearm vasoconstriction in humans. Unloading of low-pressure cardiopulmonary baroreceptors (CPBR) was accomplished by application of low levels (-10 and -20 mm Hg) of lower body negative pressure (LBNP). The authors measured the plasma norepinephrine (NE) and epinephrine, the mean arterial pressure (MAP), and the forearm vascular resistance (FVR) responses to reflex sympathetic activation by LBNP. ANP infusion (0.1 microgram.kg-1.min-1) decreased (p less than 0.01) basal MAP, as well as plasma renin activity and plasma aldosterone levels (p less than 0.05). ANP infusion also reduced (p less than 0.01) plasma NE responses to both levels of LBNP and tended to decrease both epinephrine and FVR during ANP infusion at -20 mm Hg LBNP (p = 0.8). These data suggest that exogenous ANP inhibits the reflex sympathetic responses that occur with CPBR unloading. The blunted plasma NE responses to CPBR unloading parallel the attenuation of FVR response to LBNP during ANP infusion, despite significant LBNP-induced hypotension.