Comparison of skin necrosis in rats by using a new microneedle electrocautery, standard-size needle electrocautery, and the Shaw hemostatic scalpel.

"Microneedle" electrocautery was compared against the standard-size needle electrocautery and the Shaw hemostatic scalpel to determine the differences in tissue necrosis when used as a cutting instrument. Incisions were made on the dorsal skin of anesthetized white rats using each of the three devices with the no. 15 scalpel as control. The specimens were submitted for histological evaluation. The microneedle caused less necrosis than the standard-size needle electrocautery (0.18 vs 0.27 mm, p < 0.01) and less necrosis than the Shaw hemostatic scalpel set at 220 degrees F (0.18 vs 0.25 mm, p < 0.05). The microneedle electrocautery was also found to be an instrument that causes very little tissue distortion during fine dissection and helps to minimize blood loss in craniofacial and neurosurgical operations.

Clear cell sarcoma of tendons and aponeuroses and malignant blue nevus arising in prepubescent children. Report of two cases and review of the literature.

The low incidence of malignant melanoma in children makes the diagnosis of this disease problematic for clinicians and pathologists. The diagnosis becomes especially difficult when the melanoma is a rare variant of conventional melanoma, such as clear cell sarcoma of tendons and aponeuroses (CCSTA), and malignant blue nevus (MBN). In this report we describe two prepubescent children, one with a MBN, and one with CCSTA. The patient with MBN also developed acute lymphoblastic leukemia, and died of metastatic malignant melanoma within 1 year of diagnosis. We present the histological and clinical features of these cases and review the literature on these rare tumors arising in prepubescent children.

Esculinase (beta-glucosidase) for the rapid estimation of activity in bacteria utilizing a hydrolyzable substrate, p-nitrophenyl-beta-D-glucopyranoside.

The ability of bacteria to hydrolyse esculin is an important phenotypic characteristic for their identification. The presence of 'esculinase' is especially useful in identifying genera of the Enterobacteriaceae and in separating Bacteroides, Listeria, and group D streptococci from other pathogens. Three methods have been used to measure esculin hydrolysis. Each of these methods suffered from limitations. A new procedure employing the hydrolysable substrate p-nitrophenyl-beta-D-glucopyranoside was developed. This method required only 15 min incubation at either room temperature or 35 degrees C, may be used either qualitatively or quantitatively, and is inexpensive. The sensitivity and specificity of this method was found to be equivalent to that of the standard methodology.

Measurement of active constitutive beta-D-glucosidase (esculinase) in the presence of sodium desoxycholate.

The hydrolysis of esculin in the presence of bile has been utilized for many years for the identification of bacteria. It is especially useful in differentiating species of the genus Streptococcus. The procedure is a two-step one. First, the bacterium must grow in a particular concentration of bile, and second, it must hydrolyze esculin. The hydrolysis of esculin has traditionally been determined by the brown-black color that results when one of the hydrolysate products, esculetin, reacts with iron in the medium. The procedure requires incubation for 24 h or more. A method was developed based on the measurement of constitutive beta-glucosidase (esculinase) with the repression of this enzyme by bile equivalent (sodium desoxycholate) that required only 30 min. p-Nitrophenyl-beta-D-glucopyranoside was the esculinase substrate, and sodium desoxycholate was substituted for bile salts. After inoculation, a yellow color was equivalent to the brown-black seen in the 40% bile-esculin reaction. The reagent was dispensed in test tubes and was stable for 6 months. The 30-min procedure correlated well with the conventional 24-h bile-esculin agar tube. Streptococcus pneumoniae could also be identified because of the rapid lysis it exhibited in the substrate solution.

Corynebacterium diphtheriae endocarditis: sustained potential of a classical pathogen.

This communication concerns a case of endocarditis caused by Corynebacterium diphtheriae. The patient was a 35-year-old male drug addict who was brought to the hospital with fever, chills, and abdominal pain. Two days after admission, blood cultures were found to be growing gram-positive rods suggestive of diphtheroids. Repeated blood cultures grew the same organism, which was identified as a nontoxigenic strain of C. diphtheriae. The patient subsequently was identified as having acquired immune deficiency syndrome. Although isolates are divided into toxigenic and nontoxigenic strains, all isolates of C. diphtheriae should be considered potentially toxigenic. Because diphtheria generally is considered only of historic interest, few laboratories perform tests to identify it and instead report all isolates as "diphtheroids" or Corynebacterium. Because all isolates are potentially toxigenic, and because there is a large reservoir of nonimmunized people, laboratories must be alert to possible serious epidemiologic situations.

Methylumbelliferyl-beta-D-glucuronide-based medium for rapid isolation and identification of Escherichia coli.

Escherichia coli is the most common gram-negative microbe isolated and identified in clinical microbiology laboratories. It can be identified within 1 h by oxidase, indole, lactose, and beta-glucuronidase tests. The oxidase and indole tests are performed as spot tests, and lactose fermentation is read directly from MacConkey agar. It was found that 4-methylumbelliferyl-beta-D-glucuronide could be incorporated directly into a modified MacConkey agar to directly detect the presence of beta-glucuronidase. Other characteristics of MacConkey agar were not affected. The incorporation of 4-methylumbelliferyl-beta-D-glucuronide into modified agar obviated the need for manufacture, quality control, and incubation of reagent-containing test tubes. The time needed to identify E. coli strains was reduced from 1 h to 5 min, and the ability to detect this species in mixed specimens was also enhanced.

Measurement of microbial alpha-amylases with p-nitrophenyl glycosides as the substrate complex.

The detection of alpha-amylase is commonly used in clinical microbiology laboratories to aid in differentiating Streptococcus bovis from other streptococci. It is also useful in identifying Eikenella corrodens and the gravis subspecies of Corynebacterium diphtheriae and in separating species of the genera Bacteroides, Clostridium, Actinomyces, and Bacillus. Currently, the most frequently used procedure utilizes starch as the substrate and iodine as the indicator. Starch is incorporated into a agar medium, the isolate is inoculated on the surface, and the medium is incubated for 24 to 48 h. A 15-min test containing p-nitrophenyl polyglycosides as the substrate complex was developed to yield results comparable with the agar-based starch test. The reagent was made in liquid form, 0.20 ml per tube, and could be incubated either in ambient air or at 35 degrees C. When dried, the p-nitrophenyl polyglycoside reagent could be stored at 0 degrees C for 4 weeks.

Rapid and economical identification and antimicrobial susceptibility test methodology for urinary tract pathogens.

To decrease the time and cost of processing urine cultures, we devised a critical pathway to identify and perform antibiotic susceptibility tests on commonly isolated microbial pathogens within 6 h of growth detection. The strategy was based on eliminating expensive kits and automated procedures when not required. A pathway utilizing a statistical matrix and three rapid biochemical tests required to identify the most common pathogen, Escherichia coli, was developed. This species, which represented 82% of urinary isolates, was identified in 1 h for less than 10% the cost of a commercial kit. The specificity of the 1-h E. coli identification battery was greater than or equal to 99.9% with a sensitivity of 93%. In addition, this critical pathway, adapting published methods, permitted the identification of other enteric pathogens, the group D streptococci, and Pseudomonas aeruginosa within 4 to 6 h. Furthermore, it accounted for other microbes that required longer periods of incubation. The pathway also included a rapid disk diffusion sensitivity test. Utilizing the critical pathway strategy, 76% (E. coli frequency of 0.82 X E. coli sensitivity of 0.93) of all urinary pathogens were identified within 1 h, and 98% were identified within 4 h with an antibiotic sensitivity test available within 6 h after the observation of growth. Costs were reduced from 2.5 to 5.0 times. This methodology is applicable to other specimen types.

Giant cell tumor ("osteoclastoma") of the pancreas: a tumor of epithelial origin.

Carcinomas of the pancreas with giant cells are not rare, but those containing osteoclast-like tumor cells are quite unusual. This report documents a pancreatic neoplasm comprising both easily recognizable well-differentiated adenocarcinoma and osteoclast-like tumor. The literature on the "osteoclastoma" of the pancreas is reviewed. Evidence for its epithelial deviation is supported strongly by the present case.

Aphthoid ulcerations in gastric candidiasis.

Tiny aphthoid erosions appear to represent the earliest detectable radiographic change in gastric candidiasis. In this report, the radiographic appearance of these lesions is correlated with gross and microscopic pathologic anatomy, and the progression of these ulcerations to deeper linear furrows is illustrated. It is hoped that the detection of the gastric candidiasis at this early stage will hasten therapy, and thus decrease the risk of fulminant infection in the immunocompromised host.

Fibrothecoma of the broad ligament.

We present a patient with a primary extraovarian fibrothecoma, an extremely rare lesion originating in the broad ligament. Possible sources of origin and significance are discussed.