Reduced mucin sulfonation and impaired intestinal barrier function in the hyposulfataemic NaS1 null mouse.

OBJECTIVE: Sulfate (SO(4)(2-)) is an abundant component of intestinal mucins and its content is decreased in certain gastrointestinal diseases, including inflammatory bowel disease. In this study, the hyposulfataemic NaS1 sulfate transporter null (Nas1(-/-)) mice were used to investigate the physiological consequences of disturbed sulfate homeostasis on (1) intestinal sulfomucin content and mRNA expression; (2) intestinal permeability and proliferation; (3) dextran sulfate sodium (DSS)-induced colitis; and (4) intestinal barrier function against the bacterial pathogen, Campylobacter jejuni. METHODS: Intestinal sulfomucins and sialomucins were detected by high iron diamine staining, permeability was assessed by fluorescein isothiocyanate (FITC)-dextran uptake, and proliferation was assessed by 5-bromodeoxyuridine (BrdU) incorporation. Nas1(-/-) and wild-type (Nas1(+/+)) mice received DSS in drinking water, and intestinal damage was assessed by histological, clinical and haematological measurements. Mice were orally inoculated with C jejuni, and intestinal and systemic infection was assessed. Ileal mRNA expression profiles of Nas1(-/-) and Nas1(+/+) mice were determined by cDNA microarrays and validated by quantitative real-time PCR. RESULTS: Nas1(-/-) mice exhibited reduced intestinal sulfomucin content, enhanced intestinal permeability and DSS-induced colitis, and developed systemic infections when challenged orally with C jejuni. The transcriptional profile of 41 genes was altered in Nas1(-/-) mice, with the most upregulated gene being pancreatic lipase-related protein 2 and the most downregulated gene being carbonic anhydrase 1 (Car1). CONCLUSION: Sulfate homeostasis is essential for maintaining a normal intestinal metabolic state, and hyposulfataemia leads to reduced intestinal sulfomucin content, enhanced susceptibility to toxin-induced colitis and impaired intestinal barrier to bacterial infection.

A peculiar case of Campylobacter jejuni attenuated aspartate chemosensory mutant, able to cause pathology and inflammation in avian and murine model animals.

An attenuated Campylobacter jejuni aspartate chemoreceptor ccaA mutant caused gross pathological changes despite reduced colonisation ability in animal models. In chickens, the pathological changes included connective tissue and thickening of the mesenteric fat, as well as the disintegration of the villus tips in the large intestine, whereas in mice, hepatomegaly occurred between 48-72 hours post infection and persisted for the six days of the time course. In addition, there was a significant change in the levels of IL-12p70 in mice infected with the C. jejuni ccaA mutant. CcaA isogenic mutant was hyper-invasive in cell culture and microscopic examination revealed that it had a "run" bias in its "run-and-tumble" chemotactic behaviour. The mutant cells also exhibited lower level of binding to fucosylated and higher binding to sialylated glycan structures in glycan array analysis. This study highlights the importance of investigating phenotypic changes in C. jejuni, as we have shown that specific mutants can cause pathological changes in the host, despite reduction in colonisation potential.

The cell surface mucin MUC1 limits the severity of influenza A virus infection.

Cell surface mucin (cs-mucin) glycoproteins are constitutively expressed at the surface of respiratory epithelia where pathogens such as influenza A virus (IAV) gain entry into cells. Different members of the cs-mucin family each express a large and heavily glycosylated extracellular domain that towers above other receptors on the epithelial cell surface, a transmembrane domain that enables shedding of the extracellular domain, and a cytoplasmic tail capable of triggering signaling cascades. We hypothesized that IAV can interact with the terminal sialic acids presented on the extracellular domain of cs-mucins, resulting in modulation of infection efficiency. Utilizing human lung epithelial cells, we found that IAV associates with the cs-mucin MUC1 but not MUC13 or MUC16. Overexpression of MUC1 by epithelial cells or the addition of sialylated synthetic MUC1 constructs, reduced IAV infection in vitro. In addition, Muc1-/- mice infected with IAV exhibited enhanced morbidity and mortality, as well as greater inflammatory mediator responses compared to wild type mice. This study implicates the cs-mucin MUC1 as a critical and dynamic component of the innate host response that limits the severity of influenza and provides the foundation for exploration of MUC1 in resolving inflammatory disease.

MUC13 protects colorectal cancer cells from death by activating the NF-κB pathway and is a potential therapeutic target.

MUC13 is a transmembrane mucin glycoprotein that is over produced by many cancers, although its functions are not fully understood. Nuclear factor-κB (NF-κB) is a key transcription factor promoting cancer cell survival, but therapeutically targeting this pathway has proved difficult because NF-κB has pleiotropic functions. Here, we report that MUC13 prevents colorectal cancer cell death by promoting two distinct pathways of NF-kB activation, consequently upregulating BCL-XL. MUC13 promoted tumor necrosis factor (TNF)-induced NF-κB activation by interacting with TNFR1 and the E3 ligase, cIAP1, to increase ubiquitination of RIPK1. MUC13 also promoted genotoxin-induced NF-κB activation by increasing phosphorylation of ATM and SUMOylation of NF-κB essential modulator. Moreover, elevated expression of cytoplasmic MUC13 and NF-κB correlated with colorectal cancer progression and metastases. Our demonstration that MUC13 enhances NF-κB signaling in response to both TNF and DNA-damaging agents provides a new molecular target for specific inhibition of NF-κB activation. As proof of principle, silencing MUC13 sensitized colorectal cancer cells to killing by cytotoxic drugs and inflammatory signals and abolished chemotherapy-induced enrichment of CD133+ CD44+ cancer stem cells, slowed xenograft growth in mice, and synergized with 5-fluourouracil to induce tumor regression. Therefore, these data indicate that combining chemotherapy and MUC13 antagonism could improve the treatment of metastatic cancers.

Two novel mucin genes down-regulated in colorectal cancer identified by differential display.

Epithelial mucins are large, secreted and cell surface glycoproteins involved in epithelial cell protection, adhesion modulation, and signaling. Using differential display, we have identified two novel mucin cDNAs (dd34 and dd29), hereafter designated MUC11 and MUC12, respectively, that are down-regulated in colorectal cancers. Northern blots demonstrated polydisperse signals characteristic of mucin transcripts in RNA from normal colon that were absent in colorectal cancer. Both cDNAs were mapped by fluorescence in situ hybridization to chromosome band 7q22, the location of the MUC3 mucin gene, thus suggesting that there may be a cluster of mucin genes at this locus. The sequences of both differential display clones were extended by a combination of screening libraries and PCR. The 2.8-kb MUC11 cDNA composite encoded 35 serine/threonine-rich, mucin-like degenerate 28 amino acid tandem repeats. The MUC12 cDNA composite encoded a putative transmembrane mucin containing two extracellular cysteine-rich, EGF-like domains, a coiled-coil region, and a mucin-like domain consisting of 28 amino acid degenerate tandem repeats. Distinct patterns of expression of MUC11, MUC12, and MUC3 mRNAs were observed in a range of normal human tissues. MUC12 mRNA was not expressed in any of six colorectal cancer cell lines examined and was down-regulated or absent in 6 of 15 (40%) tumors compared with matched normal colonic tissue. In contrast, MUC11 showed a different pattern of mRNA expression, with four of these lines showing low levels and the other two lines showing relatively high levels of MUC11 transcripts. Expression of MUC11 was down-regulated in the tumors of 12 of 15 (80%) paired samples. Structural homology of MUC12 with rat, mouse, and human MUC3 and human and rat MUC4/ASGP2 indicate that there is a distinct subfamily of transmembrane mucins with conserved epidermal growth factor domains. The homology of MUC12 with epidermal growth factor-like growth factors and its down-regulation in colorectal cancers, together with known interactions between rat MUC4 and c-erbB-2 growth factor receptors, suggests that MUC12 may be involved in epithelial cell growth regulation.

Transactivation-deficient p73alpha (p73Deltaexon2) inhibits apoptosis and competes with p53.

p73 has recently been identified as a structural and functional homolog of the tumor suppressor protein p53. Overexpression of p53 activates transcription of p53 effector genes, causes growth inhibition and induced apoptosis. We describe here the effects of a tumor-derived truncated transcript of p73alpha (p73Deltaexon2) on p53 function and on cell death. This transcript, which lacks the acidic N-terminus corresponding to the transactivation domain of p53, was initially detected in a neuroblastoma cell line. Overexpression of p73Deltaexon2 partially protects lymphoblastoid cells against apoptosis induced by anti-Fas antibody or cisplatin. By cotransfecting p73Deltaexon2 with wild-type p53 in the p53 null line Saos 2, we found that this truncated transcript reduces the ability of wild-type p53 to promote apoptosis. This anti-apoptotic effect was also observed when p73Deltaexon2 was co-transfected with full-length p73 (p73alpha). This was further substantiated by suppression of p53 transactivation of the effector gene p21/Waf1 in p73Deltaexon2 transfected cells and by inhibition of expression of a reporter gene under the control of the p53 promoter. Thus, this truncated form of p73 can act as a dominant-negative agent towards transactivation by p53 and p73alpha, highlighting the potential implications of these findings for p53 signaling pathway. Furthermore, we demonstrate the existence of a p73Deltaexon2 transcript in a very significant proportion (46%) of breast cancer cell lines. However, a large spectrum of normal and malignant tissues need to be surveyed to determine whether this transdominant p73 variant occurs in a tumor-specific manner.

Mucin core protein expression in colorectal cancers with high levels of microsatellite instability indicates a novel pathway of morphogenesis.

Particular mucinous phenotypes have been associated with serrated epithelial polyps of the colon. These polyps also show a high frequency of DNA instability. The aim of this study was to examine the expression of mucins in colorectal cancers that arise through the suppressor and mutator pathways. The immunohistochemical distribution of the human apomucins MUC1, MUC2, MUC4, and MUC5AC was determined in 93 sporadic colorectal cancers classified previously (J. R. Jass et al., J. Clin. Pathol., 52: 455-460, 1999) according to levels of DNA microsatellite instability (MSI) as 22 MSI-high (MSI-H), 24 MSI-low (MSI-L), and 47 MS stable (MSS). MUC2 expression was observed in 19 (86%) MSI-H, 10 (42%) MSI-L, and 15 (32%) MSS cancers (P = 0.0001); and MUC5AC expression was observed in 17 (77%) MSI-H, 8 (33%) MSI-L, and 13 (28%) MSS cancers (P = 0.0003). There was no association between MUC1 or MUC4 expression and MSI status. The mucinous phenotype described in serrated polyps (MUC2+/MUC5AC+) was seen in 15 (68%) of 22 MSI-H and only 10 (14%) of 71 MSI-L/MSS cancers (P < 0.0001). Increased expression of the secretory mucins MUC2 and MUC5AC was observed in sporadic MSI-H cancers. Identical mucin changes and DNA MSI occurred in serrated polyps of the colorectum, which suggests that these lesions may represent precursors of MSI-H cancers.

MUC1 epithelial mucin (CD227) is expressed by activated dendritic cells.

The MUC1 mucin (CD227) is a cell surface mucin originally thought to be restricted to epithelial tissues. We report that CD227 is expressed on human blood dendritic cells (DC) and monocyte-derived DC following in vitro activation. Freshly isolated murine splenic DC had very low levels of CD227; however, all DC expressed CD227 following in vitro culture. In the mouse spleen, CD227 was seen on clusters within the red pulp and surrounding the marginal zone in the white pulp. Additionally, we confirm CD227 expression by activated human T cells and show for the first time that the CD227 cytoplasmic domain is tyrosine-phosphorylated in activated T cells and DC and is associated with other phosphoproteins, indicating a role in signaling. The function of CD227 on DC and T cells requires further elucidation.

Occult axillary lymph node metastases in breast cancer do matter: results of 10-year survival analysis.

Axillary lymph node status is one of the most powerful prognostic factors for patients with breast cancer and is often critical in stratifying patients into adjuvant treatment regimens. In 203 apparently node-negative cases of breast cancer, a combination of immunohistochemical staining and step-sectioning identified occult metastases in 25% of cases. Ten-year follow-up information is available for these patients. Histologic features of the primary tumor and immunohistochemical staining for estrogen receptor, progesterone receptor, Her-2, and p53 were also evaluated. With multivariate analysis, both occult metastases and higher histologic grade of the primary tumor were independent predictors of disease-free survival. Histologic grade was the only significant independent predictor of overall survival. Estrogen receptor, progesterone receptor, Her-2, and p53 status did not predict the presence of metastases or survival when all tumor types were considered together. Metastases >0.5 mm significantly predicted a poorer disease-free survival when invasive ductal carcinomas were considered alone. Histologic grade was significantly associated with disease-free survival in the premenopausal and perimenopausal patients but not in the postmenopausal patients. The presence of occult metastases approached significance for overall survival in the premenopausal and perimenopausal patients but not in the postmenopausal patients.

Immunohistochemical staining patterns of MUC1, MUC2, MUC4, and MUC5AC mucins in hyperplastic polyps, serrated adenomas, and traditional adenomas of the colorectum.

We studied the distribution of the four human apomucins MUC1, MUC2, MUC4, and MUC5AC in hyperplastic polyps, serrated adenomas, and traditional adenomas of the colorectum using immunohistochemical techniques, with the aim of comparing and contrasting their patterns of expression. A series of 12 hyperplastic polyps, 27 serrated adenomas, and 20 traditional adenomas was studied. No significant change in apomucin expression was observed in traditional adenomas compared with normal colorectal epithelium, except for MUC5AC, which was present in 12 of the adenomas (60%) and only 20% of the normal samples. In both hyperplastic polyps and serrated adenomas, MUC2 and MUC5AC mucin expression was consistently and markedly increased. In 50% of the hyperplastic polyps, MUC4 was reduced but in the remaining cases was similar to normal. Loss of MUC4 expression was observed in all serrated adenomas. MUC1 was not increased in the hyperplastic polyps but increased expression was seen in 17 of the serrated adenomas (63%). Similar altered distribution patterns of MUC2, MUC4, and MUC5AC were seen in hyperplastic polyps and serrated adenomas, whereas traditional adenomas showed little change from normal patterns of expression. Although hyperplastic polyps are commonly defined as benign lesions without neoplastic potential, the similar phenotypes of hyperplastic and serrated adenomas and the existence of mixed polyps suggest that these lesions may represent a histogenetic continuum.

Progesterone stimulates production and secretion of MUC1 epithelial mucin in steroid-responsive breast cancer cell lines.

The effects of oestrogen and progesterone on expression of the MUC1 epithelial mucin were examined in MCF7 and ZR-75-1 breast cancer cells grown in steroid-free medium. Oestrogen caused an increase in cell growth and both cellular and secreted MUC1 in both cell lines. However, after correcting for increases in cellular protein, there was no clear changes. Progesterone, in combination with oestrogen, caused significant increases (over 2-fold, P<0.01) in cellular and secreted MUC1 when compared with oestrogen alone in both cell lines despite no or small increases in cellular protein. Growth of ZR-75-1 cells in a competitive inhibitor of O-glycosylation demonstrated that the increased detection by ELISA was not due to altered glycosylation. Progesterone may modulate expression of MUC1 in steroid-responsive breast cancer cells.

Effect of interferon-gamma and TNF-alpha on MUC1 mucin expression in ovarian carcinoma cell lines.

In view of the potential uses of cell surface tumour associated antigens in novel anticancer treatment, a study was designed to investigate whether the biological response modifiers interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha) could effect the expression of an epitope on the tumour associated MUC1 epithelial mucin. Four ovarian carcinoma cell lines showing high (OAW42 and GG) and low (JAM and PE01) basal expression of MUC1 were treated with 10-1000 U/mL of IFN-gamma or TNF-alpha for one or five days. Changes in MUC1 expression in cells exposed to IFN-gamma or TNF-alpha were monitored using an ELISA technique with the monoclonal antibody BC2 which reacts with a core protein epitope on the MUC1 mucin, and then corrected for the number of viable cells present. TNF-alpha had little effect on MUC1 expression, but one or five days exposure to IFN-gamma significantly increased MUC1 expression (p < 0.01) in all cell lines including the two cell lines that initially showed little or no expression.

Prognostic significance of MUC1 epithelial mucin expression in breast cancer.

The epithelial mucin produced by the MUC1 gene is present in the apical cell membrane of normal breast epithelial cells and is highly expressed in many breast cancers. Several studies have provided conflicting evidence regarding the relationship between MUC1 expression and survival in breast cancer patients. In this study a detailed immunohistological analysis of MUC1 expression was performed using monoclonal antibody BC2 and was related to other tumor characteristics and patient survival. Patients whose tumors showed MUC1 expression in greater than 75% of tumor cells had significantly poorer disease-free and overall survival (P < .05). The proportion of cells showing cytoplasmic MUC1 expression was prognostically significant, but the proportion of cells that lined gland spaces showing apical membrane staining was of no prognostic significance. A high level of MUC1 expression was significantly associated with the presence of axillary node metastases and estrogen receptors but not with other tumor characteristics.

Expression of a polymorphic epithelial mucin antigen defined by the monoclonal antibody BC2 in ovarian carcinoma. Use of the BC2 antibody for the detection of micrometastases.

The BC2 monoclonal antibody, which binds to an epitope on the peptide backbone of polymorphic epithelial mucin, was tested immunohistochemically for reactivity with epithelial ovarian carcinoma. This epitope was expressed in 90 of 91 malignant ovarian tumors; in 88% of these, more than 50% of the tumor cells expressed the epitope. In 94% of the positive tumors, the epitope was expressed on the cell membrane; in 56%, cytoplasmic expression was evident; and in 39%, secreted extracellular antigen was detected. Differences were not clearly discernible between dissimilar histotypes with respect to the percentage of cells expressing antigen and antigen localization. Thirteen of 19 benign ovarian cystadenomas also expressed the epitope, but staining was weak and restricted to the luminal surface of the cell membrane. A blind retrospective immunohistochemical analysis of all second-look laparotomy biopsy specimens from 20 patients also was performed. All four patients in whom microscopic disease was detected by standard pathologic assessment had BC2-positive metastases. Of seven patients in whom recurrent disease subsequently developed despite negative pathologic findings, four had biopsy specimens containing BC2 antigen-positive adenocarcinoma-like cells. Of the nine patients with negative results on operation and no recurrence, one had biopsy specimens containing BC2 antigen-positive adenocarcinoma-like cells. Mesothelial cells, although typically negative, expressed the epitope in one biopsy specimen, necessitating caution in the interpretation of positive cells. The BC2 antibody is reactive with most epithelial ovarian carcinomas and appears to be a useful tool for the detection of micrometastases.

Demonstration of two ovarian tumor-associated antigens in primary and metastatic breast, gastric, and colonic tumors.

The presence of two ovarian tumor-associated antigens (TAAs) defined by monoclonal antibodies BC3 and CC4 in primary and metastatic breast, gastric, and colonic malignant tumors was determined by immunohistochemistry. The BC3 TAA was present in all gastric, colonic, and breast tumors, typically with a large proportion of tumor cells expressing antigen. The CC4 TAA was present in most of these tumors, generally with a lower proportion of tumor cells expressing antigen compared with that of BC3. Both of these TAAs were found in some epithelial cells in normal breast, stomach, and colon, however, the location of the two TAAs in normal tissue was different. With the use of both antibodies, an increase in the number of tumor cell-positive lymph nodes was found in patients with breast, gastric, colonic, and ovarian tumors, including detection of micrometastases in nodes from patients considered node negative on purely morphologic grounds. Immunohistochemical detection of micrometastases derived from adenocarcinomas appears to be superior to purely morphologic detection.

Expression of MUC2 epithelial mucin in breast carcinoma.

AIMS: To examine the expression of the MUC2 epithelial mucin in breast carcinoma; to relate this to patient survival. METHODS: Sections from 210 breast carcinomas were stained with the anti-MUC2 core protein monoclonal antibody, 4F1, using an immunoperoxidase technique. The proportion of tumour cells positively stained and the localisation and intensity of any staining were recorded. Expression of MUC2 was compared with histological type and grade, tumour size, presence of nodal metastases, presence of oestrogen receptors, and menopausal status. The prognostic value of MUC2 expression was examined using Kaplan-Meier survival analysis. RESULTS: MUC2 mucin was detected in 19% of cases of invasive carcinoma, in 11% of cases of carcinoma in situ, where present, but very rarely in adjacent normal breast epithelium. Presence of MUC2 was significantly associated with a shorter disease free interval (p < 0.05), although the observed difference in duration of overall survival was not significant. CONCLUSIONS: The MUC2 detected in breast carcinoma may be underglycosylated or staining may represent detection of the protein core before the completion of glycosylation. The virtual absence of 4F1 reactivity in normal breast epithelium suggests that, unlike the MUC1 mucin, the MUC2 mucin is not highly expressed by these cells. The mechanism by which expression of MUC2 affects the biology of breast tumours is unclear, although expression may be a reflection of general derepression of genes during tumour progression.

Circulating tumour-associated mucin concentrations, determined by the CASA assay, in healthy women.

This investigation was undertaken to establish a reference range for tumour-associated MUC1 mucins in the serum of healthy women of the ages at risk for adenocarcinoma of the ovary and breast. Blood samples and clinical information were obtained from 5,000 women attending a breast screening mammography clinic. Data from women diagnosed with breast carcinoma and those subsequently diagnosed with other cancers were omitted from the reference range. Mucin concentrations were measured using the CASA assay which detects the protein core of MUC1 encoded mucins. Multiple linear regression analysis showed no effect on CASA concentrations by non-malignant changes to the breast, menopausal status, presence/absence of the reproductive tract, parity or history of hormone use. However, CASA concentrations were significantly increased in smokers (P < 0.001) and progressively increased with age (P < 0.001). These data show that these factors must be given consideration when setting upper limits of normal using MUC1 protein core binding assays.

Circulating mucins as tumor markers in ovarian cancer (review).

Because a highly sensitive and specific serum marker for ovarian carcinoma has not been reported, it is unlikely that there will be an application of serum markers for screening for this disease in asymptomatic women. However, many oncologists use serum tumor markers initially to differentiate epithelial ovarian carcinoma from benign gynecological conditions prior to surgery, so as to ensure appropriate surgical referral, and then to monitor the clinical course of disease during and after adjuvant therapy. The most commonly performed tumor marker assay in ovarian cancer (CA125) has been extremely valuable in patient management, but this marker is also elevated in a considerable proportion of patients with benign gynecologic diseases and endometriosis, and a relatively small proportion of patients with early stage disease. A new class of serum tumor markers, the highly glycosylated, high molecular weight mucins, have enormous potential in the management of ovarian cancer patients, since the use of assays for these markers may overcome many of the problems associated with CA125. Indeed, when used in combination with CA125, some mucin-based assays have increased the sensitivity and specificity of detection, thereby eliminating many false positive results seen with patients with benign disease and endometriosis, and also predicted disease recurrence in the majority of patients before clinical symptoms became apparent. These markers are the subject of this review, with particular attention to the commercially-available mucin-based assays.

Prostate-specific antigen (PSA) and cancer-associated serum antigen (CASA) in distinguishing benign and malignant prostate disease.

The Prostate-Specific Antigen (PSA) and the Cancer-Associated Serum Antigen (CASA) assay for the MUC1 mucin were compared in the serum of 303 patients with malignant or benign prostatic disease. Using cutpoints of 4, 10, and 20 micrograms/l, PSA was elevated in 93%, 81%, and 64% of patients with prostate cancer (n = 113), with corresponding specificities of 55%, 84%, and 96% in benign prostate disease (prostatic hyperplasia or prostatitis, n = 190). Using the recommended cutpoint of 4 Units/ml, CASA was elevated in 38% of patients with prostate cancer, with a specificity of 91% in benign disease. PSA and CASA showed a poor correlation in prostate cancer (r = 0.367) and benign disease (r = 0.158), and CASA was elevated in some PSA negative samples. Used together, PSA > or = 20 micrograms/l and CASA > or = 4 kU/l gave perfect specificity in benign disease, with a corresponding sensitivity of 29% (positive and negative predictive values of 100% and 70%, respectively). However, this combination gave no improvement over the use of PSA alone, with sensitivity 47% when the cutpoint was raised to give perfect specificity. These data suggest that CASA is of little use as an adjunct to PSA in the differentiation of benign and malignant prostate disease.

Zinc in selected hospital diets. Comparison of analysis vs. calculation.

Sample hospital meals for breakfast and the noon and evening meals for regular, ovo-lacto-vegetarian, and renal diets were collected for seven consecutive days. The daily zinc content of each diet was determined, using atomic absorption spectrophotometric analysis and by calculation, using the USDA provisional tables on the zinc content of individual foods. The data indicated that the provisional tables provide a reasonable estimation of zinc content of regular or renal diets with errors approximately 10%. However, a 35% overestimation occurred for vegetarian diets. A major cause of error between assayed and calculated values was probably due to substituting items not included in the tables. The mean zinc content for the regular diet, as offered, was 97% of the adult recommended allowance for zinc, while the vegetarian diet provided 81% of the allowance. The average renal diet contained 49% of the allowance. Certain types of vegetarian and low-protein diets may be inadequate in total and/or available zinc. Also important in evaluating hospital diets for adequacy of zinc are the actual intake and the condition of the patient.