Impact of beta-carotene supplementation through red palm

A 10-month long feeding trial was conducted to assess the impact of beta-carotene supplementation through red palm oil (RPO) with the focus on vitamin A status, morbidity status and acceptability of an RPO-incorporated noon-meal as a dietary supplement among two cohorts of 409 (experimental) and 346 (control) preschool children in two southern districts of rural Tamil Nadu, selected by stratified random sampling. Information was gathered on ocular symptoms of vitamin A deficiency and anthropometry, and blood samples were drawn at baseline and final rounds for estimation of serum beta-carotene, retinol and tocopherol. Data about Socioeconomic Status (SES) were collected once during the study period, while information on attendance, consumption and morbidity was recorded by preschool teachers. The results showed the following. 1. Significant improvement in the vitamin A status of children in terms of disappearance of Bitot's spots (50.0 per cent) in the experimental group vs. 28.0 per cent in the control group. 2. After feeding of RPO, incidence rate of new Bitot's spots cases was low at 2.13 in the experimental children vs. 4.78 in control children. 3. Marked improvement in the serum beta-carotene levels after 10 months of feeding. 4. RPO is acceptable to children as an edible grade oil as there is no perceptible difference in the consumption pattern between experimental and control children.     

A biomechanical evaluation of the Christensen temporomandibular joint implant

The Christensen TMJ implant is often used clinically as a total joint replacement of the temporomandibular joint. The system consists of a thin fossa component and a condylar component with a polished articular head. In this study, we analyzed the surface finish and the metal structure of the components. We also measured the contact areas between the two components for different load levels. Such information may be useful in evaluating clinical performance as well as in making future improvements in the design of these implants.     

Two mechanisms for tumor evasion of preexisting cytotoxic T-cell responses: lessons from recurrent tumors.

Tumors evade host immunity at both the induction and effector phases Most studies have focused on tumor evasion at the induction phase, and, due in part to poor antitumor CTL responses to most tumors, the mechanism for evasion of CTL effector function is less clear. Here we have taken advantage of the strong CTL responses to a costimulator B7-1-transfected tumor to study the mechanism for tumor evasion of preexisting host immunity. We have investigated six independent recurrent tumors isolated from mice that were challenged with and had rejected B7-1-transfected J558 (J558-B7) tumors. Because the mice had developed strong antitumor CTL responses, these recurrent tumors must have evaded preexisting antitumor CTLs. Indeed, whereas the parental J558-B7 cell line is efficiently lysed by the ex vivo tumor-infiltrating lymphocytes, all of the recurrent tumors are resistant to such lysis. Interestingly, the recurrent tumors can be divided into two groups. The group 1 tumors have vastly reduced levels of cell surface MHC class I with a concurrent reduction in the expression of multiple genes devoted to MHC class I antigen presentation. In contrast, the group 2 tumors have lost the expression of costimulatory molecule B7-1 while retaining cell surface MHC class I and expression of all antigen presentation genes studied. These results demonstrate that tumors can evade preexisting CTLs either by avoiding presentation of the tumor antigen or, surprisingly, by down-regulation of costimulatory molecules. The paradoxical requirements of both antigen and costimulatory molecules at the effector phase raised an interesting question on the nature of antitumor immunity.     

Resistance to the promotion of glutathione S-transferase 7-7-positive liver lesions in Copenhagen rats.

Previously, we have shown that Copenhagen (Cop) rats are highly resistant to the induction of putative preneoplastic, glutathione S-transferase 7-7 (GST 7-7)-positive liver lesions following treatment with a modified resistant hepatocyte protocol. The objective of the current study was to establish the time course for the development of resistance and examine potential resistance mechanisms in Cop rats using F344 rats as susceptible controls. Male Cop and F344 rats (n = 25), 7-8 weeks of age, were initiated with diethylnitrosamine (200 mg/kg) and promoted 3 weeks later with four doses of 2-acetylaminofluorene (20 mg/kg) and a 2/3 partial hepatectomy (PH). Groups of rats from each strain were killed on days 2, 4, 7, 14 and 21 post-PH, 2 h after receiving bromodeoxyuridine. Cop livers contained similar numbers of GST 7-7-positive lesions to F344 livers on days 2 and 4 post-PH. The percent volume of liver occupied by these lesions did not differ between the strains on days 2, 4 and 7 post-PH. On day 14, however, approximately 29% of the liver volume in F344 rats was occupied by lesions, whereas in Cop rats this was significantly less (approximately 9%, P < 0.001). On day 21, lesions occupied approximately 58% of F344 rat livers and only approximately 6% of Cop livers. Despite these differences, the labeling index of hepatocytes was not significantly different between the strains at any time point, either within lesions or within surrounding normal liver. Furthermore, the apoptotic indices were not different between the strains at any time. However, differences were found in the extent of lesion remodeling (redifferentiation) and in the pattern of oval cell response following PH in Cop livers. By day 14 post-PH, approximately 76% of Cop liver lesions showed evidence of remodeling, compared with only approximately 14% of F344 lesions. The oval cell response to PH was equivalent in the two strains up to day 4 post-PH but by day 7, in F344 livers there was extensive migration of these cells into the liver parenchyma, whereas in Cop livers, the response remained localized to the portal regions. These results suggest that Cop resistance occurs at the promotion stage and not the initiation stage of carcinogenesis. Resistance appears not to be due to a lower proliferation rate nor to a higher apoptotic rate within Cop lesions. Precocious remodeling and/or a diminished oval cell response, however, may contribute to the resistance of Cop rats to the growth of GST 7-7-positive hepatic lesions.     

Antimicrobial and radical modulation activity of AV-07, a poly-herbal formula

An extract of AV-07 was investigated for various biological activities. Pretreatment of mice with the AV-07 extract significantly protected them from lethal infection with E. coli. ESR spectroscopy showed that the extract produced radicals under alkaline conditions and enhanced the radical intensity of sodium ascorbate, suggesting its pro-oxidant action at higher concentrations. The extract effectively scavenged superoxide anion, produced by hypoxanthine-xanthine oxidase reaction and hydroxyl radical, produced by Fenton reaction. These data demonstrate that AV-07 extract contains various bioactive substances, suggesting its medicinal efficacy.     

Liver hyperplasia is not necessarily associated with increased expression of c-fos and c-myc mRNA

Experiments were designed to investigate the expression of three cell-cycle-dependent proto-oncogenes in response to two different types of proliferative stimuli: compensatory cell proliferation after partial hepatectomy (PH) or CCl4 and liver hyperplasia induced by the mitogens ethylene dibromide (EDB) and cyproterone acetate (CPA). Steady-state levels of messenger RNAs for c-fos and c-myc were found to be elevated after PH or CCl4 with a maximum increase between 0.5 and 2 h for c-fos and at 2-3 h for c-myc and a rapid decline after 3 h. However, when liver cell proliferation was induced by mitogens, no increase in the expression of c-fos mRNA was observed with both EDB or CPA during the first 24 h. In addition, elevated expression of c-myc was found only in liver hyperplasia induced by EDB, but not with CPA. While the expression of c-myc mRNA and c-fos mRNA was different in the two types of proliferative stimuli, that of c-Ha-ras and c-Ki-ras was similar in all the experimental groups. Cell proliferation monitored by means of incorporation of labelled thymidine into DNA or mitotic index at 24 h following PH, EDB and CPA occurred at a similar extent in all the experimental groups. Our data indicate that the transient and sequential expression of cell-cycle-related genes may vary in response to proliferative stimuli of different nature and suggest that increased expression of cell-cycle-related genes may not be a necessary prerequisite for the entry of the cells into the cell cycle.     

Lung cancer in men aged 40 or younger

Twenty-nine cases of lung cancer occurring in men aged 40 or less were examined at autopsy. Histologic types of cancer and metastatic patterns in this group of patients were similar to those seen in middle-aged or elderly patients except for a lower occurrence of lymphatic spread in the younger group.     

Persistence and lateral movement of 2,4-dichlorophenoxy acetic acid and picloram on power line rights-of-way

Soil persistence and lateral movement of 2,4-D (2,4-dichlorophenoxy acetic acid) and picloram (4-amino-3,5,6-trichloropicolinic acid) were examined following their application as a stem-foliage spray for brush control on two power line rights-of-way. Ditches to collect runoff water were located 3, 10, 20, and 30 m downslope from the treated areas. Runoff water and soil samples were collected after 0.14, 0.43, 0.57, 1, 2, 4, 7, 8, 11, 15, 16, and 48 weeks and were analyzed for picloram and 2,4-D residues. Only 3 of 85 soil samples downslope from the target areas contained residues of 2,4-D, and only 1 of 85 down slope samples contained a detectable residue of picloram. Of 56 runoff water samples, only 11 contained 2,4-D residues and only 1 contained residues of picloram. The greatest distances downslope at which residues were detected in runoff water were 20 and 10 m for 2,4-D and picloram, respectively. No residues of either herbicide were recovered in soil or water at 15 weeks or 48 weeks after spraying. Despite normal rainfall frequency and amounts in the first several weeks after spraying in mid-June, significant runoff of either herbicide was not evident at either study site.