Silicic acid limitation drives bloom termination and potential carbon sequestration in an Arctic bloom.

The spring diatom bloom in the Arctic Ocean accounts for significant annual primary production leading to the most rapid annual drawdown of water-column pCO. Late-winter waters in the Atlantic Arctic & Subarctic Provinces (AASP) have lower silicic acid concentrations than nitrate, which suggests diatom blooms may deplete Si before N. Here we test a facet of the hypothesis that silicic acid limitation terminates the spring diatom bloom in the AASP and the sinking of the senescent and dead diatoms helps drive carbon sequestration.

Living with fair use and TEACH: a quest for compliance.

With the expansion of Web-based courses in nursing education, faculty members are faced with a greater responsibility to be copyright compliant. This article reviews the changes in copyright law. The Conference on Fair Use (CONFU), the passage of the Digital Millennium and Copyright Act (DMCA), the passage of the Technology Education and Copyright Harmonization (TEACH) Act, and recent legal cases will be discussed.

The negative impact of the repeal of the Arkansas motorcycle helmet law.

Background: On July 1, 1997, Arkansas became the first state in 14 years to repeal their adult helmet law. We examined the clinical and financial impact of this repeal.

Methods: A 6-year retrospective review was conducted of the University of Arkansas for Medical Sciences trauma registry including the 3 years before and the 3 years after the repeal of the helmet law.

A survey of domestic violence in a university emergency department.

Objectives: To determine prevalence of domestic violence among female patients presenting to the department.

Methods: An anonymous survey distributed to female patients presenting over a 30-day period.

Results: Response rate was 12.

An AIDS training program for rural mental health providers.

A total of 194 mental health care providers in Arkansas, primarily from rural areas and small communities, participated in a four-hour training program designed to improve their knowledge about the psychosocial and neuropsychiatric aspects of HIV and AIDS. Participants' responses to questionnaires completed before and after training indicated that the program was successful in achieving its goal. However, only a minimal number of providers reported completing drug, alcohol, and sexual histories and AIDS risk assessments for any of their patients before the training occurred.

Cultured adult rat jejunal explants as a model for studying regulation of CYP3A.

Enzymes within the CYP3A subfamily are major Phase I drug-metabolizing enzymes present in hepatocytes and small bowel enterocytes. These enzymes are highly inducible in the liver by many structurally diverse compounds, including a number of commonly used medications. Studies indicate that CYP3A enzymes present in small bowel enterocytes are also inducible.

Heterogeneity of cytochrome P450IIIA expression in rat gut epithelia.

The P450IIIA (CYP3A) cytochromes are a major family of enzymes that play an important role in the metabolism of many medications, including cyclosporine A, as well as some dietary xenobiotics, including aflatoxin B1. The purpose of the studies was to detect, localize, and characterize P450IIIA enzymes present throughout the digestive tract. To this end, P450IIIA-specific antibodies were used to examine gut epithelial microsomes and histological tissue sections obtained from the digestive tract of both male and female rats.

Familial visceral neuropathy with neuronal intranuclear inclusions: diagnosis by rectal biopsy.

A family with a visceral neuropathy manifested as chronic idiopathic intestinal pseudo-obstruction is reported. Diagnoses were made histologically by simple rectal biopsy. Discrete eosinophilic intranuclear inclusions, diagnostic of a disease known as neuronal intranuclear inclusion disease, were found in the submucosal ganglion cells.

Electron microscopic definition of intestinal endocrine cells: immunogold localization and review.

Intestinal mucosal biopsy specimens processed during the past 25 years were used to example the ultrastructural characteristics of intestinal endocrine cells. The cells were defined on the basis of morphologic criteria and, when feasible, with specific antisera and immunogold staining. The hypothesis was that each endocrine cell, once well defined, should be identifiable on the basis of standard morphologic criteria not requiring specific immunostaining.

Characterization of mucous cell synthetic functions in a new primary canine gastric mucous cell culture system.

Mucin is a critical component of the protective layer secreted by gastrointestinal mucous cells. A detailed understanding of the molecular processing of gastric mucin and the physiology of its secretion has been limited by the lack of an adequate model for their study. We have developed a primary culture system of canine gastric mucous cells that has permitted us to study their synthetic and secretory functions.

Long-term maintenance of the adult pattern of liver-specific expression for P-450b, P-450e, albumin and alpha-fetoprotein genes in intrasplenically transplanted hepatocytes.

Hepatocytes isolated from livers of Fischer 344 rats and transplanted into the spleens of rats from the same strain survived for at least 15 mo in the absence of immunosuppressive drugs. Hepatocytes attached themselves only in the red pulp of the spleen, most commonly in clumps without a discernible structure. Throughout the 15-mo period, intrasplenically transplanted hepatocytes expressed cytochrome P-450b, P-450e and albumin messenger RNAs, whereas alpha-fetoprotein messenger RNA was not expressed.

Studies of the rectal mucosa in coeliac sprue: the intraepithelial lymphocyte.

The dynamics of the rectal surface epithelial lymphocyte and leucocyte response to wheat, gluten, and gliadin enema challenges in control individuals and in patients with coeliac sprue in remission is shown. There is a clear increase in intraepithelial lymphocytes and polymorphonuclear (PMN) leucocytes in response to these enemas in coeliac sprue, but not in controls. The peak response was at eight hours and cleared within 24 hours.

Glycine-extended progastrin processing intermediates: accumulation and cosecretion with gastrin.

Glycine-extended intermediates of peptide processing serve as substrates for carboxyl-terminal amidation, hence activation, of many brain-gut peptides. To explore the dynamics of accumulation and secretion of these important intermediates we utilized primary cultures of canine antral mucosal G-cells as a model system. Glycine-extended progastrin processing intermediates (G-Gly) accumulated rapidly in G-cells cultured in ascorbate-deficient media, exhibiting a fourfold increase over a 51-h culture period, while gastrin content fell to less than half of the initial level.

Neuronal dysplasia and chronic intestinal pseudoobstruction: rectal biopsy as a possible aid to diagnosis.

We report a patient with an unusual cause of chronic intestinal pseudoobstruction, i.e., neuronal intestinal dysplasia.

HLA antigens in Whipple's disease.

The prevalence of HLA-A and B antigen loci in patients with Whipple's disease was determined from data obtained in a review of the literature and from personal communications. Data on the HLA-A and B locus typing of 30 patients were available (with the exception that 1 of the patients was not typed for the HLA-B locus), and for an additional 18 patients, HLA-B27 data were available. Of the 47 patients typed for B27, 13 (28%) were B27 positive.

Immunoelectron microscopic localization of HLA-DR antigen in control small intestine and colon and in inflammatory bowel disease.

We have elucidated the distribution of I2 (HLA-DR) antigen in control and inflammatory bowel disease specimens, using immunoelectron microscopic methods. Control small intestinal epithelium and inflammatory bowel disease epithelium expressed 12 antigen, while control colonic epithelium did not. I2 expression by enterocytes was more frequent on the lateral and basal surface than on the microvillus surface.

The intestinal and rectal epithelial lymphocyte in AIDS. An electron-microscopic study.

Injury to the gastrointestinal tract may be mediated in part by the intraepithelial lymphocyte. In this study, we utilized electron microscopy to define the morphological appearance of 86 intestinal and 55 rectal intraepithelial lymphocytes observed in 11 patients with acquired immunodeficiency syndrome (AIDS), and one patient with AIDS-related lymphadenopathy syndrome. The data obtained from intraepithelial lymphocytes of AIDS are compared to those from 106 normal intestinal epithelial lymphocytes and 52 untreated celiac sprue epithelial lymphocytes.

Gastric xanthomatosis and cholestasis. A causal relationship.

We report two cases of gastric xanthomatosis which developed in patients with marked cholestasis. In both cases, one with acute and one with chronic cholestasis, the gastric xanthomas disappeared with resolution of the cholestasis. A review of the literature is also provided.