An outbreak of type A botulism associated with a commercial cheese sauce

BACKGROUND: Although botulism is rare, recognition of a possible case of this illness represents a public health emergency. To prevent more cases, prompt investigation must be done to determine whether illness is linked to commercial product or restaurant. Botulism can masquerade as other illnesses, and seemingly unlikely foods can harbor botulinum toxin. OBJECTIVE: To confirm the diagnosis and determine the cause and extent of an outbreak of botulism associated with food served at a delicatessen. DESIGN: Retrospective cohort study of patrons of the delicatessen; laboratory analysis of food, serum samples, and stool samples; and traceback of implicated food. SETTING: Community in Georgia. PARTICIPANTS: Patrons of the delicatessen. MAIN OUTCOME MEASURES: Botulinum toxin in food, serum, or stool and Clostridium botulinum in food and stools. RESULTS: 8 of 52 patrons (15%) met the case definition for botulism. In 4 of the 8 patrons, and illness other than botulism was initially diagnosed. Five of the 8 were hospitalized, and 1 died. Stool cultures from 4 patrons yielded type AC. botulinum, and two serum samples contained botulinum toxin. All ill persons ate food from the delicatessen on 1 October 1993. Of the 22 persons who ate at the delicatessen that day, all 8 ill persons but none of the 14 well persons ate a potato stuffed with meat and cheese sauce. An open can of cheese sauce contained type A botulinum toxin and yielded C botulinum on culture. Cheese sauce experimentally inoculated with C botulinum spores became toxic after 8 days at a temperature of 22 degrees C (room temperature). CONCLUSIONS: A commercial, canned cheese caused a botulism outbreak. This product readily becomes toxic when contaminated by C botulinum spores and left at room temperature. Mild botulism caused by unusual vehicles may be misdiagnosed. Botulism should be included in the differential diagnosis of persons with signs or symptoms of acute cranial nerve dysfunction.     

Localized involutional lipoatrophy: a clinicopathologic study of 16 patients

BACKGROUND: Localized loss of adipose tissue without antecedent clinical or histologic inflammation is termed idiopathic lipoatrophy. OBJECTIVE: Our purpose was to study the clinical and pathologic features in 16 patients with clinically focal lipoatrophy and a distinct pathologic pattern of fat lobule involution. METHODS: A retrospective study of 16 patients was performed. RESULTS: The buttocks and proximal extremities were involved most frequently. Lesions were solitary in 10 patients and multiple in six. Nine patients had received intramuscular or intraarticular corticosteroid or antibiotic injections in the affected areas before the development of lipoatrophy. Histologic examination showed that individual fat cells were decreased in size and separated by hyaline material. Progressive reduction in the size and number of adipocytes resulted in diminutive fat lobules with prominent vessels resembling embryonic fat lobules. Some adipocyte masses were acidophilic. Scattered macrophages, confirmed by immunoperoxidase staining for CD68 (KP-1), were identified within the fat lobules and surrounding connective tissue. Yellow-gray granules were recognized within the cytoplasm of macrophages in nine cases. Macrophages becoming lipophages were observed by electron microscopy in one case. Other inflammatory cells were not prominent. CONCLUSION: This is a common pattern of postinjury response to fat tissue characterized by macrophage infiltration of the fat lobules in variable numbers. The term involutional lipoatrophy is justified by the resemblance of the distinctive pathologic changes to embryonic fat lobules.     

An open multicentre study of tropisetron for cisplatin-induced nausea and vomiting

1. P2X-receptors are ligand-gated ion channels which activate within milliseconds of agonist binding, causing rapid cellular depolarization and excitation. This makes them ideally suited to mediate the rapid neurotransmitter functions of adenosine 5'-triphosphate (ATP). 2. The initial postjunctional response of the vas deferens and most blood vessels to sympathetic nerve stimulation is a rapid, transient excitatory junction potential (EJP). With sufficient stimulation EJPs summate and the membrane depolarizes sufficiently to open voltage-dependent calcium channels, initiating a calcium action potential and contraction. 3. EJPs are inhibited by desensitization of the P2X-receptor by the stable agonist alpha, beta-methyleneATP (alpha, beta-meATP) and by the P2X-receptor antagonists ANAPP3, suramin and pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid, indicating that they are consequent upon activation of the P2X-receptor. 4. The P2X-receptor was originally defined by contractile studies in smooth muscle preparations, where a rank order of agonist potency of alpha, beta-meATP > > 2-methylthioATP (2-meSATP) > or = ATP was found. However, recent results show that the potency of ATP and 2-meSATP, but not alpha, beta-meATP, is decreased by 100-to 1000-fold by breakdown and when this is prevented, ATP and 2-meSATP are more potent than alpha, beta-meATP as agonists at the P2X-receptor. 5. This conclusion was supported by the cloning and functional expression of the P2X1-receptor from the rat bladder. A total of seven P2X-subunits have since been cloned and the P2X1-subunit is thought to be the predominant subunit expressed in vascular smooth muscle cells.     

Increased expression of cyclin D1 and the Rb tumor suppressor gene in c-K-ras transformed rat enterocytes

Activating mutations in the c-K-ras gene occur in about 40% of human colorectal carcinomas, yet the role of this oncogene in tumorigenesis is not known. We have developed a model cell culture system to study this problem, utilizing the immortalized but non-tumorigenic epithelial cell line IEC18, originally derived from normal rat intestine epithelium. These cells were cotransfected with the drug resistance selectable marker tk-neo and the plasmid pMIKcys, which encodes a mini human c-K-ras gene (15 kb) containing a cysteine mutation at codon 12. Drug resistant clones were isolated. Clones which also expressed the activated c-K-ras gene displayed a transformed morphology, decreased doubling time, increased level of diacylglycerol, anchorage independent growth in soft agar and an aneuploid karyotype and they were also tumorigenic when injected into nude mice. These clones also displayed increased expression, at both the mRNA and protein levels, of cyclin D1 and Rb. These findings may be of clinical relevance since human colorectal tumors also frequently display increased expression of both cyclin D1 and Rb. This model system may be useful for understanding the role and interrelationship between activation of the c-K-ras oncogene and increased expression of cyclin D1 and Rb in colorectal tumorigenesis.     

Rapid thyroxine to 3,5,3'-triiodothyronine conversion and nuclear 3,5,3'-triiodothyronine binding in rat cerebral cortex and cerebellum

Thyroxine (T(4)) to 3,5,3'-triiodothyronine (T(3)) conversion was evaluated in vivo in cerebral cortex, cerebellum, and anterior pituitary of male euthyroid Sprague-Dawley rats. Tracer quantities of (125)I-T(4) and (131)I-T(3) were injected into controls and iopanoic acid-pretreated rats 3 h before isolation of nuclei from these tissues. Specifically-bound nuclear (131)I-T(3), denoted T(3)(T(3)); (125)I-T(3), denoted T(3)(T(4)); and (125)I-T(4) were extracted and identified by chromatography. Plasma iodothyronines were similarly quantitated. In control rats, nuclear T(3)(T(3)) (percent dose per milligram DNA x 10(-4)) was 174+/-31 in cerebral cortex, 50+/-9 in cerebellum, and 932+/-158 in pituitary (all values, mean+/-SEM). Nuclear T(3)(T(4)) (percent dose per milligram DNA x 10(-4)) was 23.3+/-3.3 in cortex, 3.5+/-0.6 in cerebellum, and 39.4+/-6.9 in pituitary. Two-thirds of nuclear T(3)(T(4)) derived from local T(4) to T(3) conversion. Nuclear T(3)(T(4)) in all tissues was reduced to less than 15% of its control value by iopanoic acid treatment and all of the residual nuclear T(3)(T(4)) could be accounted for by plasma T(3)(T(4)). Nuclear T(3)(T(3)) binding was not inhibited by iopanoic acid. These results indicate there is rapid local T(4) to T(3) conversion in rat brain and nuclear binding of the T(3) produced. We have previously found that local T(3)(T(4)) production is the source of approximately 50% of the T(3) in rat anterior pituitary. The present observations that the ratio of locally derived nuclear T(3)(T(4)) to nuclear T(3)(T(3)) is much higher in cerebral cortex (0.1) and cerebellum (0.04) than in anterior pituitary (0.015) suggest that this locally produced T(3)(T(4)) is the predominant source of intracellular T(3) in these portions of rat brain.     

Resident training in nursing home care: survey of successful educational strategies

OBJECTIVE: To identify educational strategies for resident training in nursing home care deemed successful by a large number of programs. DESIGN: A mail survey with three follow-up mailings. PARTICIPANTS: Directors of accredited internal medicine and family practice residency programs. MEASUREMENTS: Open- and closed-ended questionnaire eliciting curricular content, instructional strategies, and evaluation techniques from programs offering a nursing home experience. Identification of barriers to implementation of a nursing home curriculum and recommendations for success were requested. MAIN RESULTS: Of the 814 surveys mailed, 537 were returned for a response rate of 66%. Nursing home experiences were required in 86% of family practice residency programs but in only 25% of internal medicine programs. Most geriatric medicine curricular content areas were taught in the nursing home; however, relatively little emphasis was given to rehabilitation, organization, and financing of health care, and coordination of care between acute and chronic settings. Direct patient care, bedside rounds, and lectures were the most common instructional strategies reported. Evaluation approaches included faculty observations, resident attendance, and chart reviews with written and skill-based examinations infrequent. Availability of faculty and conflict with other rotations were identified as the principal barriers to implementation of nursing home rotations. An organized nursing home curriculum supervised by enthusiastic faculty using a longitudinal rotation format with resident involvement in an interdisciplinary team was recommended. CONCLUSIONS: Educational strategies exist for successful implementation of a residency nursing home curriculum. Greater priority must be given to training residents in nursing home care and developing nursing home faculty to substantially increase the number and quality of physicians who practice in this setting.     

Effect of myocardial fiber direction on epicardial potentials

BACKGROUND: Understanding the relations between the architecture of myocardial fibers, the spread of excitation, and the associated ECG signals is necessary for addressing the forward problem of electrocardiography, that is, predicting intracardiac and extracardiac ECGs from known intracardiac activity. So far, these relations have been studied experimentally only in small myocardial areas. In this study, we tested the hypothesis that potential distributions measured over extensive epicardial regions during paced beats reflect the direction of superficial and intramural fibers through which excitation is spreading in both the initial and later stages of ventricular excitation. We also tried to establish whether the features of the epicardial potential distribution that correlate with fiber direction vary as a function of pacing site, intramural pacing depth, and time elapsed after the stimulus. An additional purpose was to compare measured epicardial potentials with recently published numerical simulations depicting the three-dimensional spread of excitation in the heart muscle and the associated potential fields. METHODS AND RESULTS: The hearts of 18 mongrel dogs were exposed and 182 to 744 unipolar electrograms were recorded from epicardial electrode arrays (2.3 x 3.0 to 6.5 x 6.5 cm). Hearts were paced at various intramural depths through an intramural needle. The overall number of pacing sites in 18 dogs was 241. Epicardial potential distributions, electrographic waveforms, and excitation time maps were displayed, and fiber directions in the ventricular wall underlying the electrodes were determined histologically. During the early stages of ventricular excitation, the position of the epicardial maxima and minima revealed the orientation of myocardial fibers near the pacing site in all cases of epicardial and intramural pacing and in 60% of cases of endocardial or subendocardial pacing. During later stages of propagation, the rotation and expansion of the positive areas correlated with the helical spread of excitation through intramurally rotating fibers. Marked asymmetry of potential patterns probably reflected epicardial-endocardial obliqueness of intramural fibers. Multiple maxima appeared in the expanding positive areas. CONCLUSIONS: For 93% of pacing sites, results verified our hypothesis that epicardial potential patterns elicited by ventricular pacing reflect the direction of fibers through which excitation is spreading during both the initial and later stages of propagation. Epicardial potential distributions provided information on the site of origin and subsequent helical spread of excitation in an epicardial-endocardial, endocardial-epicardial, or double direction. Results were in agreement with previously published numerical simulations except for the asymmetry and fragmentation of the positive areas.     

Dissolution of calcified gallstones. Part I. Correlation of in vitro dissolution kinetics in methyl tert-butyl ether with patterns of calcification by computed tomography

RATIONALE AND OBJECTIVES: The authors evaluated the relationship between stone computed tomography (CT) attenuation patterns and the kinetics of dissolution with methyl tertbutyl ether (MTBE). METHODS: Single moderately and heavily calcified gallstones from 40 patients were selected from a gallstone library and classified for pattern of calcification by in vitro CT scan (dense, rim, core, and laminated). Each stone was placed in a 10-mL aliquot of MTBE for 24 hours. Stone residue was blotted dry and weighted at 8, 16, and 24 hours. Results were normalized with respect to stone size. RESULTS: Only 1 of 40 (4%) specimens dissolved to particulate matter that was smaller than 2 mm. All (6 of 6) stones that were densely calcified showed virtually no dissolution. The rate of gallstone dissolution varied temporally within the rim, core, and laminated stone categories and was related to the composition of the layer exposed to the solvent at any given time. CONCLUSION: The success and rate of dissolution may be predicted by the pattern of calcification as determined by computed tomography (CT).     

Assessment of colour Doppler tissue imaging using test-phantoms

An investigation has been carried out on the velocity resolution, spatial resolution and accuracy of Doppler images as part of a study into the Doppler display of cardiac tissue motion. Test-phantoms were designed to perform this work and images were captured on a computer. The characteristics of the phantom images and of the image capture process were studied. The smallest spatial detail that was observed in the Doppler image was 3 mm by 3 mm. Doppler receive gain and Doppler ensemble size both affected velocity resolution. Different target materials gave different measures for velocity resolution. This could be related to the different back-scatter intensities of the materials.