Determination of Fat,Moisture, and Protein in Meat and Meat Products by Using the FOSS FoodScan Near-Infrared Spectrophotometer with FOSS Artificial Neural Network Calibration Model and Associated Database: Collaborative Study

A collaborative study was conducted to evaluate the repeatability and reproducibility of the FOSS FoodScan near-infrared spectrophotometer with artificial neural network calibration model and database for the determination of fat, moisture, and protein in meat and meat products. Representative samples were homogenized by grinding according to AOAC Official Method 983.18. Approximately 180 g ground sample was placed in a 140 mm round sample dish, and the dish was placed in the FoodScan. The operator ID was entered, the meat product profile within the software was selected, and the scanning process was initiated by pressing the start button. Results were displayed for percent (g/100 g) fat, moisture, and protein. Ten blind duplicate samples were sent to 15 collaborators in the United States. The within-laboratory (repeatability) relative standard deviation (RSDr) ranged from 0.22 to 2.67% for fat, 0.23 to 0.92% for moisture, and 0.35 to 2.13% for protein. The between-laboratories (reproducibility) relative standard deviation (RSDR) ranged from 0.52 to 6.89% for fat, 0.39 to 1.55% for moisture, and 0.54 to 5.23% for protein. The method is recommended for Official First Action.

Growth and characterization of N-methyl-N-nitrosourea-induced mammary tumors in intact and ovariectomized rats

It is well established that 85-90% of chemically induced mammary tumors in rats will disappear or diminish significantly in size after the ovaries are removed from the animal. However, it is less well established whether a high percentage of these mammary tumors will grow back with prolonged time after ovariectomy. It is also not known what changes in gene expression take place in the tumors as they develop an independence from hormones for growth. This study was carried out to investigate this. Virgin, 50-day-old female Sprague-Dawley rats were injected with N-methyl-N-nitrosourea (MNU) at the dose of 50 mg MNU/kg body wt. When at least one mammary tumor had grown to 1.0-1.5 cm in one dimension, the animal was bilaterally ovariectomized and reduction and then re-growth of the tumors monitored. Control animals were treated identically except they were not ovariectomized when tumors appeared. Re-growths and new tumors and tumors that developed in the control rats were removed when they reached 1.0-1.5 cm in diameter and all animals were killed 25 weeks after the MNU injection. All the animals in the study (100%) developed mammary tumors after MNU injection with an average latency of 56.5 days. After ovariectomy, 93% of the tumors showed 50% or more reduction in size and 76% of the tumors could not be detected by palpation. However, in 96% of the animals where tumor reduction or disappearance occurred, a re-growth or new mammary tumor development took place with an average latency period of 52.8 days from the day of ovariectomy. Of these post-ovariectomy tumors, 36% occurred at a location where tumors had developed prior to ovariectomy, but 64% appeared at new locations. The circulating levels of 17beta-estradiol (E2) was undetectable in the ovariectomized (OVX) rats and significant reduction was seen in the serum concentrations of progesterone (P4), prolactin (PRL), growth hormone (GH) and insulin-like growth factor-I (IGF-I). The tumors from the OVX rats showed indications of progression as evident from loss of differentiation and invasive characteristics. Comparison between tumors from OVX and intact rats revealed a significantly increased expression of P450 aromatase and elevated activation of extracellular signal-regulated kinase 1 and 2, but reduced levels of the progesterone receptor and cyclin D1 in OVX rats. However, the estrogen receptor (ER) content remained similar in tumors from both groups, at least at the protein level, and so did the expression of IGF-I, IGF-II, insulin receptor substrate-1 (IRS1), IRS-2 and epidermal growth factor receptor. IGF-I receptor (IGF-IR) and ErbB-2 were expressed, respectively, in 50 and 70% of the tumors from the OVX animals, whereas these genes were expressed in 100% of the tumors from the intact rats. It is concluded that chemically induced rat mammary tumors may still depend on the ER and local syntheses of E2 and growth factors for growth initially after ovariectomy. However, as these tumors progress, they develop a more aggressive phenotype and lose their dependency on the ER and possibly growth factors.

Parous rats regain high susceptibility to chemically induced mammary cancer after treatment with various mammotropic hormones

Parity in humans and rats provides significant protection against mammary tumor development. This study was carried out to investigate whether treatment of parous rats with mammotropic hormones would affect methyl-nitrosourea (MNU)-induced mammary carcinogenesis. Parous rats were treated with 17beta-estradiol (E2), progesterone (P4) and thyroxine (T4) alone or in combination. E2 (20 microg/60 days) and P4 (20 mg/60 days) were administered by silastic tubing and T4 in the drinking water (3 microg T4/ml). Hormonal treatments commenced 7 days before MNU injection and continued for 33 weeks. Animals were palpated weekly for tumor detection. The effects of the hormonal treatments on the circulating concentrations of E2, P4, growth hormone (GH), prolactin (PRL), T4 and insulin-like growth factor-I (IGF-I) after 7 days of treatment, the time of MNU injection, was assessed. Animals treated with E2 had significantly elevated circulation concentrations of GH, PRL and P4, and serum levels of E2 were more consistent in this group than in the other animal groups. P4 treatment caused elevation in P4 concentration in serum but did not affect the circulating levels of other hormones. The proliferation of the mammary gland at the time of MNU injection was elevated in animal groups treated with E2 either alone or with P4 and T4 and in animals treated with P4 alone, but the mammary gland was most differentiated in untreated parous rats and least in animals treated with E2 either alone or with P4 and T4. Mammary tumor incidence was 10% in parous rats that did not receive any hormonal treatment. Treatments with E2 or P4 alone significantly increased the susceptibility of parous animals to 67 and 50.0%, respectively; a tumor incidence similar to that of untreated AMV rats (64%). Parous rats treated with E2 plus P4 had tumor incidence higher than 90%. T4 administered did not affect mammary carcinogenesis.

Topical bactrim versus trimethoprim and sulfonamide against nocardia keratitis

PURPOSE

The conventional treatment of Nocardia keratitis is with topical sulfonamides. Recently, topical trimethoprim and sulfamethoxazole (Bactrim) has been suggested as treatment. This study compares the in vitro efficacy against Nocardia asteroides of Bactrim and various ratios of trimethoprim and a sulfonamide.

METHODS

Antibiotic disks were soaked with various ratios of trimethoprim and sulfacetamide sodium. They contained trimethoprim alone, sulfacetamide sodium alone, and both trimethoprim and sulfacetamide sodium at ratios of 1:40, 1:20, and 1:5. Disks containing Bactrim were also prepared. Each disk was placed on blood agar plates streaked with N. asteroides. The plates were incubated at 37 degrees C for 72 hours and then examined.

RESULTS

Trimethoprim alone showed minimal effect. Sulfacetamide sodium alone had a clearance zone of 12 mm. The plates of trimethoprim and sulfacetamide sodium at ratios of 1:40, 1:20, and 1:5 had clearance zones of 14 mm, 17 mm, and 27 mm, respectively. Bactrim had a clearance zone of 70 mm.

CONCLUSION

Trimethoprim or sulfacetamide sodium alone is not as effective as both drugs together. As the ratio of the two drugs was changed, potency differed against Nocardia organisms. Bactrim was the most effective antibiotic against Nocardia organisms. It should be the recommended agent for the treatment of Nocardia keratitis.

Evaluation of the AnaeroPack Campylo system for growth of microaerophilic bacteria

Growth of microaerophilic bacteria in the AnaeroPack Campylo (Mitsubishi Gas Chemical America, Inc., New York, N.Y.) atmosphere generation system was compared to growth in the CampyPak Plus jar and CampyPak pouch (Becton-Dickinson Microbiology Systems [BDMS], Cockeysville, Md.). Growth in the AnaeroPack Campylo system was considered equivalent to or better than growth obtained in the CampyPak Plus and CampyPak pouch systems for 48 of the 50 Helicobacter pylori strains and for all 28 Campylobacter species tested. All of the 78 organisms tested were recovered in each system in equivalent colony counts. Two strains of H. pylori grown in the AnaeroPack Campylo system were observed to have colony morphology growth discrepancies when compared to growth in the two BDMS systems. Atmosphere failure with the AnaeroPack Campylo was not detected with Campylobacter jejuni ATCC 33291 used as a growth control. The AnaeroPack Campylo system is easy to use and supports the growth of campylobacters and H. pylori.

Enhancement of bismuth antibacterial activity with lipophilic thiol chelators

The antibacterial properties of bismuth are greatly enhanced when bismuth is combined with certain lipophilic thiol compounds. Antibacterial activity was enhanced from 25- to 300-fold by the following seven different thiols, in order of decreasing synergy: 1,3-propanedithiol, dimercaprol (BAL), dithiothreitol, 3-mercapto-2-butanol, beta-mercaptoethanol, 1-monothioglycerol, and mercaptoethylamine. The dithiols produced the greatest synergy with bismuth at optimum bismuth-thiol molar ratios of from 3:1 to 1:1. The monothiols were generally not as synergistic and required molar ratios of from 1:1 to 1:4 for optimum antibacterial activity. The most-active mono- or dithiols were also the most soluble in butanol. The intensity of the yellow formed by bismuth-thiol complexes reflected the degree of chelation and correlated with antibacterial potency at high molar ratios. The bismuth-BAL compound (BisBAL) was active against most bacteria, as assessed by broth dilution, agar diffusion, and agar dilution analyses. Staphylococci (MIC, 5 to 7 microM Bi3+) and Helicobacter pylori (MIC, 2.2 microM) were among the most sensitive bacteria. Gram-negative bacteria were sensitive (MIC, < 17 microM). Enterococci were relatively resistant (MIC, 63 microM Bi3+). The MIC range for anaerobes was 15 to 100 microM Bi3+, except for Clostridium difficile (MIC, 7.5 microM). Bactericidal activity averaged 29% above the MIC. Bactericidal activity increased with increasing pH and/or increasing temperature. Bismuth-thiol solubility, stability, and antibacterial activity depended on pH and the bismuth-thiol molar ratio. BisBAL was stable but ineffective against Escherichia coli at pH 4. Activity and instability (reactivity) increased with increasing alkalinity. BisBAL was acid soluble at a molar ratio of greater than 3:2 and alkaline soluble at a molar ratio of less than 2:3. In conclusion, certain lipophilic thiol compounds enhanced bismuth antibacterial activity against a broad spectrum of bacteria. The activity, solubility, and stability of BisBAL were strongly dependent on the pH, temperature, and molar ratio. Chelation of bismuth with certain thiol agents enhanced the solubility and lipophilicity of this cationic heavy metal, thereby significantly enhancing its potency and versatility as an antibacterial agent.

Altered expression of the WT1 wilms tumor suppressor gene in human breast cancer

The product of the WT1 Wilms tumor suppressor gene controls the expression of genes encoding components of the insulin-like growth factor and transforming growth factor beta signaling systems. The role of these growth factors in breast tumor growth led us to investigate possible WT1 gene expression in normal and cancerous breast tissue. WT1 was detected by immunohistochemistry in the normal mammary duct and lobule, and the patterns of expression were consistent with developmental regulation. In a survey of 21 infiltrating tumors, 40% lacked immunodetectable WT1 altogether and an additional 28% were primarily WT1-negative. Cytoplasmic, but not nuclear, localization of WT1 was noted in some tumor cells and WT1 was detected, sometimes at high levels, in more-advanced estrogen-receptor-negative tumors. In this highly malignant subset, the tumor suppressor protein p53, which can physically interact with WT1, was also sometimes detected. WT1 mRNA was detected in normal and tumor tissue by reverse transcription-coupled PCR. Alternative splicing of the WT1 mRNA may regulate gene targeting of the WT1 protein through changes either in its regulatory or zinc-finger domains. The relative proportions of WT1 mRNA splice variants were altered in a random sample of breast tumors, providing evidence that different tumors may share a common WT1-related defect resulting in altered regulation of target genes.

Progesterone receptors in the mouse mammary duct: distribution and developmental regulation

During pregnancy, in response to rising levels of estrogen and progesterone, mammary epithelial cells proliferate and differentiate, giving rise to lobuloalveolar structures from which milk is secreted during lactation. Progesterone, in conjunction with estrogen, also promotes mammary epithelial growth during puberty, but unlike development during pregnancy, this results in ductal rather than secretory structures. Recent studies using mice lacking progesterone receptors indicate that these receptors are essential for secretory development. This suggests that during different phases of normal mammary growth and differentiation, progesterone receptors may mediate their effects through different mechanisms, depending on the physiological state of the animal. Therefore, as a prerequisite for understanding the role of progesterone in normal mammary development, we have investigated the spatial and temporal distribution of progesterone receptor-containing cells. In the mammary epithelium of prepubertal mice, high levels of progesterone receptor mRNA and protein are present in the actively growing end buds and ductal branches as well as in the mature duct. Receptor protein was found in some but not in all epithelial cells, and these cells were characterized by large, round, or oval nuclei containing diffuse chromatin. Cytoplasmic and nuclear immunostaining were observed; interestingly, this staining occurred in separate cells that were in close proximity to each other. The relative proportion of cytoplasmic versus nuclear staining cells changed during pregnancy such that in this developmental state, the nuclear staining cells predominated. The potential significance of these observations as they pertain to normal mammary epithelial growth and differentiation are discussed.

Essential role of endogenous estrogen in directly stimulating mammary growth demonstrated by implants containing pure antiestrogens

The mammogenic actions of estrogen, although undisputed, lack definition due to uncertainties concerning the relative importance of systemic vs. local actions of the hormone. In addition to its well known, indirect effects on mammary tissue through pituitary intermediaries such as PRL and GH, recent evidence points to, but does not prove, direct estrogen action on mammary targets. The ability of exogenous estrogen to directly and locally stimulate mammary growth in vivo was previously shown in endocrine-ablated animals using small plastic pellets containing estradiol. The more important question of whether the direct action of endogenous estrogen is required for normal mammary growth and morphogenesis in the endocrine-intact animal is now investigated using direct-acting, slow-release plastic implants containing pure antiestrogens (antiestrogens with no estrogenic properties) inserted into the growth region of mammary glands. Local growth inhibition only in the immediate vicinity of the implants and not in other glands in the same mouse demonstrated the requirement of mammary tissues for endogenous, locally acting estrogen. Local actions of antiestrogens on ducts mimicked the ovariectomy-induced loss of systemic estrogen with respect to time course and morphology, with complete inhibition of ductal growth in 14 days. A second effect, in which locally acting antiestrogens simplified the pattern of ductal branching, was observed in both immature and mature animals. Two distinct mitogenic pathways, one governing ductal elongation and the other ductal maintenance, were thus affected. The inhibitory effects of antiestrogen treatment were fully reversible and not accompanied by obvious cytotoxicity. We conclude from these studies of localized estrogen receptor blockade that with respect to ductal mammogenesis, the action of estrogen is direct (acting at the level of the gland itself) and not primarily through the stimulation of pituitary mammogens.

Use of plasmid profiles in the investigation of a patient with Helicobacter pylori infection and peptic ulcer disease

Plasmids may effect bacterial virulence and antibiotic resistance, and serve as epidemiologic markers. In this study, plasmid DNA profiles of serial isolates of Helicobacter pylori showed persistence of an identical strain of this organism in a patient with duodenal ulcer disease. Three control strains of H. pylori isolated from other patients contained plasmids different from each other and from that of the original patient; two of these strains had two plasmids each. These data have important implications for further study of the epidemiology and pathogenesis of H. pylori-related diseases.

TGF-beta 1-induced inhibition of mouse mammary ductal growth: developmental specificity and characterization

TGF-beta 1, implanted into growing mouse mammary glands, was previously shown to inhibit ductal growth in an apparently normal and fully reversible manner. In this report we extend these findings to show that TGF-beta 1 inhibition is highly specific. In pregnant or hormone-treated mice, doses of TGF-beta 1 that were capable of fully inhibiting ductal elongation had little effect on the proliferation of lobuloalveolar structures. Additionally, the inhibitory action of TGF-beta 1 on ducts is epithelium-specific, resulting in cessation of DNA synthesis in the rapidly proliferating epithelium of mammary end buds, but does not inhibit DNA synthesis in the stroma surrounding the end buds. At the cellular level, transplant studies showed that TGF-beta 1 inhibited the regeneration of mammary ductal cells when implanted into mammary gland-free fat pads by suppressing the formation of new end buds, without inhibiting maintenance DNA synthesis in ductal lumenal epithelium; this observation indicates the potential of TGF-beta 1 to maintain patterning by suppressing adventitious lateral branching. The time-course of TGF-beta 1 inhibition of end buds was rapid, with cessation of DNA synthesis by 12 hr, followed by loss of the stem cell (cap cell) layer. The question of glandular exposure to TGF-beta 1 administered in EVAc implants was also investigated. Incorporation of TGF-beta 1 into EVAc was found not to degrade the hormone, while the release kinetics of the ligand from implants, its retention in the gland, and the demonstrable zone of exposure were consistent with observed inhibitory effects. These results support the hypothesis that TGF-beta 1 is a natural regulator of mammary ductal growth.

Liver abscess caused by Clostridium bifermentans following blunt abdominal trauma

A case of hepatic abscess and subsequent septicemia caused by Clostridium bifermentans is described. The abscess manifested itself on the third day after blunt trauma to the torso. The patient had nausea, vomiting, fever, evidence of hepatic dysfunction, and subphrenic gas. This case illustrates the association of hepatic abscess and blunt trauma to the torso.

Campylobacter pylori and gastroduodenal disease: a prospective endoscopic study and comparison of diagnostic tests

A series of 72 adult patients undergoing 76 upper gastrointestinal (GI) endoscopies because of GI signs or symptoms were studied for the presence of Campylobacter pylori by culture, histology, and rapid urease determination of gastric antral biopsy specimens. C. pylori was found by culture or histology in all 10 cases of gastric and duodenal ulcer, and in 77% of endoscopies with histologically proven active gastritis. Positive culture for C. pylori was highly correlated pathologically with active gastritis, but not endoscopically, and was rarely seen in the absence of acute inflammation on biopsy. There was no correlation between C. pylori and alcohol ingestion, smoking, age, sex, antibiotics, or nonsteroidal anti-inflammatory drug use. The rapid urease test was positive in 70% of cases with positive cultures and 89% with positive cultures or acridine orange stains. Acridine orange-stained histological samples were positive in 97% of cases with positive cultures. In addition, 31% of endoscopies with negative cultures were also positive by acridine orange stain. Acridine orange stain, culture, and urease reaction of antral mucosal biopsies all are effective methods for demonstration of mucosal C. pylori-like organisms. However, of the three methods used, acridine orange staining is positive in the largest group of patients and is the most sensitive method for detecting colonization of gastric antral mucosa. In general, positive urease and culture identify those patients with larger numbers of organisms on the mucosa. Differences in urease and culture positivity from case to case suggest that factors other than numbers of organisms, such as viability and urease levels, affect the results. All these results support a role for C. pylori as an aggressive factor in peptic ulcer disease and gastritis.

Cerebral hypometabolism obtained with deep pentobarbital anesthesia and hypothermia (30 C)

Cerebral metabolic and vascular effects of hypothermia (30 C) and deep pentobarbital anesthesia, separately and combined, were evaluated in 15 mongrel dogs. External cardiovascular support was not used, and mean arterial blood pressures remained greater than 60 torr. Normothermic deep pentobarbital anesthesia, characterized by an electroencephalographic (EEG) frequency of less than 1 Hz, was associated with 30% decreases in cerebral metabolic rates for oxygen (CMRO2) and glucose (CMRG) from lightly anesthetized control values. Hypothermia (30 C) alone caused similar decreases in CMRO2 and CMRG in the presence of an active EEG. The use of pentobarbital anesthesia and hypothermia combined achieved significantly greater (P less than 0.05) decreases in CMRO2 (70%) and CMRG (72%) from the control state. Cerebral vascular resistance (CVR) increased by 70% (P less than 0.05) during hypothermia and about 20% when pentobarbital was administered to normothermic dogs. In hypothermic animals the addition of pentobarbital had a minimal effect on CVR. No alteration in the oxygen-glucose or lactate-glucose index indicative of cerebral hypoxia occurred in any experimental group. This study indicates that barbiturates combined with hypothermia decrease cerebral metabolism to a greater extent than hypothermia or barbiturate alone. When cerebral hypometabolism is therapeutically necessary, barbiturates may be indicated as an adjunct to moderate hypothermia.

Brain-blood partition coefficients of 85Krypton at 37 C and 29.5 C

To permit utilization of the Kety-Schmidt technique for measuring cerebral blood flow during hypothermia, the brain-blood partition coefficients for 85krypton at 37 C and 29.5 C were determined in a series of cats. At 37 C the partition coefficient for 85krypton was 1.092 +/- 0.009; it was 0.931 +/- 0.007 (SE) at 29.5 C. These values were significantly different from each other (P less than .001).