Spontaneous infarction of a parotid gland pleomorphic adenoma. Report of a case with cytologic and radiographic overlap with a primary salivary gland malignancy.

Pleomorphic adenoma is the most common neoplasm of the parotid gland, generally presenting as a slowly enlarging, firm, well-circumscribed, painless nodule. Occasional cases have presented after a short period of rapid growth or have been associated with pain. The vast majority of these tumors are solid, but rare examples have been associated with cystic degeneration or hemorrhage. Spontaneous and tumor-associated infarction of the parotid has been reported, but these examples have been limited to infarctions of Warthin's tumors and postoperative infarctions of salivary glands. We present the case of a 48-year-old male with a one-year history of a painful, enlarging, left parotid mass associated with paresthesia of the tongue. Computed tomographic examination of the parotid demonstrated a left superficial lobe mass with a rim of enhancement and low attenuation center. Fine needle aspiration yielded necrotic debris and atypical squamous elements that were thought to be compatible with carcinoma. A superficial parotidectomy with intraoperative frozen section revealed a pleomorphic adenoma with extensive central necrosis. To our knowledge, this represents the first reported case of an infarcted pleomorphic adenoma and illustrates the potential for misinterpretation of these cytologic and radiologic findings as indicative of malignancy.     

Biology of the Galapagos shark,Carcharhinus galapagensis, in Hawai'i

Synopsis Catch records from the Hawai'i Cooperative Shark Research and Control Program, which operated in Hawai'i from 1967–1969, were examined and data on the Galapagos shark,Carcharhinus galapagensis were analyzed. A total of 304 Galapagos sharks was caught, predominantly with longlines. More female sharks were caught than males, and the catch was skewed geographically. On the island of O'ahu the highest catch rates occurred along the north and south coasts. High catch rates also occurred near points of land, where longshore currents converge. Average depth of capture was greater for juveniles (45.1 m) and mature males (60.2 m), than for subadults (38.8 m) and mature female sharks (34.2 m). Males appear to reach maturity between 205 and 239 cm total length, and females between 215 and 245 cm. Litter size ranged from 4 to 16 pups, with an average of 8.7. In Hawaiian waters Galapagos sharks are born at just over 80 cm total length. Mating and parturition apparently occur early in the year, and gestation is estimated to be about 12 months. Stomach contents consisted mainly of teleosts and benthic prey, and ontogenetic changes in diet occurred as sharks increased in size. Sharks consumed a smaller proportion of teleosts and more elasmobranchs with increasing size. Dietary diversity also increased with increasing size of shark.     

Degradation of cocaine by a mixed culture of Pseudomonas fluorescens MBER and Comamonas acidovorans MBLF.

A mixed culture that could utilize cocaine as the sole source of carbon and energy for growth was isolated by selective enrichment. The individual microorganisms within this mixed culture were identified as Pseudomonas fluorescens (termed MBER) and Comamonas acidovorans (termed MBLF). Each microorganism was shown to be unable to grow to any appreciable extent on 10 mM cocaine in the absence of the other. C. acidovorans MBLF was found to possess an inducible cocaine esterase which catalyzed the hydrolysis of cocaine to ecgonine methyl ester and benzoate. C. acidovorans was capable of growth on benzoate at concentrations below 5 mM but was unable to metabolize ecgonine methyl ester. P. fluorescens MBER was capable of growth on either benzoate as the sole source of carbon or ecgonine methyl ester as the sole source of carbon and nitrogen. P. fluorescens MBER was found to initiate the degradation of ecgonine methyl ester via ecgonine, pseudoecgonine, and pseudoecgonyl-coenzyme A. Subcellular studies resulted in the identification of an ecgonine methyl esterase, an ecgonine epimerase, and a pseudoecgonyl-coenzyme A synthetase which were induced by growth on ecgonine methyl ester or ecgonine. Further metabolism of the ecgonine moiety is postulated to involve nitrogen debridging, with the production of carbonyl-containing intermediates.     

5,7-Diphenyl-3-ureidohexahydroazepin-2-ones as Cholecystokinin-B receptor ligands

A series of 5,7-diphenyl-3-ureidohexahydroazepin-2-one cholecystokinin-B (CCK-B) receptor antagonists was synthesized using Beckmann ring expansion of a suitable 2,4-diphenylcyclohexanone as a key step. SAR studies revealed the importance of the 5-aryl group for high and selective CCK-B receptor affinity, as illustrated in compound (−)-10i (CCK-B IC₅₀ = 6.8 nM).     

Change in climatically suitable breeding distributions reduces hybridization potential between Vermivora warblers

Aim

Climate change is affecting the distribution of species and subsequent biotic interactions, including hybridization potential. The imperiled Golden-winged Warbler (GWWA) competes and hybridizes with the Blue-winged Warbler (BWWA), which may threaten the persistence of GWWA due to introgression. We examined how climate change is likely to alter the breeding distributions and potential for hybridization between GWWA and BWWA.

Location

North America.

Methods

We used GWWA and BWWA occurrence data to model climatically suitable conditions under historical and future climate scenarios. Models were parameterized with 13 bioclimatic variables and 3 topographic variables. Using ensemble modeling, we estimated historical and modern distributions, as well as a projected distribution under six future climate scenarios. We quantified breeding distribution area, the position of and amount of overlap between GWWA and BWWA distributions under each climate scenario. We summarized the top explanatory variables in our model to predict environmental parameters of the distributions under future climate scenarios relative to historical climate.

Results

GWWA and BWWA distributions are projected to substantially change under future climate scenarios. GWWA are projected to undergo the greatest change; the area of climatically suitable breeding season conditions is expected to shift north to northwest; and range contraction is predicted in five out of six future climate scenarios. Climatically suitable conditions for BWWA decreased in four of the six future climate scenarios, while the distribution is projected to shift east. A reduction in overlapping distributions for GWWA and BWWA is projected under all six future climate scenarios.

Main Conclusions

Climate change is expected to substantially alter the area of climatically suitable conditions for GWWA and BWWA, with the southern portion of the current breeding ranges likely to become climatically unsuitable. However, interactions between BWWA and GWWA are expected to decline with the decrease in overlapping habitat, which may reduce the risk of genetic introgression.     

The development and assessment of DNA and oligonucleotide probes for the specific detection of Bacillus anthracis

Two DNA probes and a number of oligonucleotide probes were designed from the virulence factor genes of Bacillus anthracis. These probes were tested for specificity against 52 B. anthracis strains and 233 Bacillus strains encompassing 23 other species. A rapid slot blotting technique was used for screening the large numbers of isolates involved. All probes tested appeared to be specific for B. anthracis under high stringency conditions. These probes could differentiate between virulent and avirulent strains. The probes were also applied to the detection of B. anthracis in routine environmental and clinical samples. A non-radioactive hybridization and detection system based on digoxigenin-11-dUTP was developed.     

mtDNA diversity in rhesus monkeys reveals overestimates of divergence time and paraphyly with neighboring species

Reconstructions of the human-African great ape phylogeny by using mitochondrial DNA (mtDNA) have been subject to considerable debate. One confounding factor may be the lack of data on intraspecific variation. To test this hypothesis, we examined the effect of intraspecific mtDNA diversity on the phylogenetic reconstruction of another Plio- Pleistocene radiation of higher primates, the fascicularis group of macaque (Macaca) monkey species. Fifteen endonucleases were used to identify 10 haplotypes of 40-47 restriction sites in M. mulatta, which were compared with similar data for the other members of this species group. Interpopulational, intraspecific mtDNA diversity was large (0.5%- 4.5%), and estimates of divergence time and branching order incorporating this variation were substantially different from those based on single representatives of each species. We conclude that intraspecific mtDNA diversity is substantial in at least some primate species. Consequently, without prior information on the extent of genetic diversity within a particular species, intraspecific variation must be assessed and accounted for when reconstructing primate phylogenies. Further, we question the reliability of hominoid mtDNA phylogenies, based as they are on one or a few representatives of each species, in an already depauperate superfamily of primates.