Plasmacytoma induction in radiochimeras

We have induced plasmacytomas (MPC) in BALB/c radiochimeras (RCh) repopulated with syngeneic hemopoietic cells carrying distinctive chromosomal markers. A group of 38 RCh that received 0.5 ml pristane, followed by Abelson virus infection 2-3 weeks later, developed 7 tumors (18.5%) of donor origin after a relatively short latency period (X = 83 +/- 8.3 days). In contrast, only 3 (2%) MPCs were observed in 149 RChs that received 0.5 ml pristane 3 times at monthly intervals. Two of them originated from host cells. Pristane-treated RChs developed a less extensive oil granuloma (OG), compared with pristane-treated intact mice. This may explain the low incidence of MPC in the former. Our findings also suggest that Abelson virus can overcome the postulated deficiency of OG. MPC induction in the pristane + Abelson-virus-treated RCh system will facilitate the further characterization of the MPC precursor cell and the localization of genetic resistance vs. susceptibility factors at the donor vs. host level.

The accelerating role of Abelson murine leukemia virus in murine plasmacytoma development: in vitro infection of spleen cells generates donor-type tumors after transfer to pristane-treated BALB/c mice

The role of Abelson murine leukemia virus (A-MuLV) in the accelerated development of murine plasmacytomas (PCs) (Potter et al., 1973: Science, 132, 592-594) was studied in a new experimental system. Spleen cells from pristane-treated or untreated BALB/c mice carrying Robertsonian 6;15 fusion chromosomes were infected in vitro with helper-free A-MuLV overnight and subsequently transplanted into the peritoneal cavity of pristane-treated or untreated BALB/c mice. Donor-derived PCs developed in 4 out of 76 pristane-treated recipients [latent periods: 38-82 (mean 51) days] that had received spleen cells from pristane-treated donors, and also in 2 out of 41 pristane-treated recipients that had received untreated donor-derived spleen cells (latent periods: 65 and 120 days). Three of the PCs in the former and both PCs in the latter group were tested for integration and expression of the v-abl gene, with positive results. This indicates that the spleen contains PC-precursor cells that can be activated by A-MuLV even before the impact of pristane. All 6 donor-origin PCs carried a translocation involving chromosome 15, band D2/3. Four of these corresponded to a typical 12;15 translocation, one was a variant 6;15 translocation and the 6th may represent a previously unidentified translocation between chromosome 15 and the lambda gene-carrying chromosome 16. No PCs developed among 29 pristane-untreated recipients that had received pristane-treated donor-derived spleen cells. In addition to PCs, monocytic tumors developed in 37 (26%) of all recipients. Their development was independent of pristane treatment of recipients but was particularly frequent in those who had received spleen cells from pristane-treated donors.

[Application of bioelectric impedance measurement in the evaluation of body fat]

We compared the data referring to the percentage of body fat in 40 healthy adults (20 males and 20 females) of different weight, aged between 18 and 33 years, measured by biological impedance analysis and skinfold thickness measurement. Of these, 26 were shown to be of normal weight, 9 overweight and 5 underweight according to the body mass index (Weight/Height). All subjects were analysed for bioelectrical impedance with a BIA-103 (Ryl-Detroit) appliance and the skinfolds were measured with a Harpenden Caliper. The correlation between the values obtained with the two methods was shown to be linear and highly significant for both sexes (males: r = 0.71; females: r = 0.77). The study also showed that the content of body fat was higher than the mean values indicated in the literature for the age range considered in 23% of the males and 31% of the females of normal weight.

A new technique for repair of mitral insufficiency caused by ruptured chordae of the anterior leaflet

Prolapse of the anterior leaflet of the mitral valve is the result of ruptured chordae, elongated chordae, or elongated or ruptured papillary muscle. Several techniques have been described for the correction of mitral valve insufficiency. However, when there is severe rupture of the chordae, the most widely accepted solution is valve replacement. We describe a technique for the creation of a neochorda with a strip of tissue from the anterior leaflet of the mitral valve. This technique was used in two patients with severe mitral valve regurgitation. Formation of a neochorda and placement of a Carpentier ring to remodel the anulus obviated the need for a valve replacement. Both patients had an uneventful recovery. Studies performed 3 and 4 months postoperatively showed competent and well-functioning valves. One patient required a valve replacement for acute mitral insufficiency 5 years later, but the other patient was doing well 3 years after the operation. Despite the limited experience, we believe this technique offers a reasonable alternative to valve replacement.

Further studies on chromosome 15 trisomy in murine T-cell lymphomas: mapping of the relevant chromosome segment

Trisomy 15 is the most common chromosomal aberration in murine T-cell lymphomas. The relevant chromosomal region responsible for the growth advantage of the 15-trisomic cell has not been defined. In order to map this region, we have induced thymic lymphomas by chemical carcinogens (DMBA or MNU) in mice with 2 different constitutional translocations, T(7;15)9H homozygotes and [T(7;15)9H X T(5;15)4Ad] FI hybrids. Twenty-two tumors developed in 90 carcinogen-treated mice. Among the 14 cytogenetically analyzed thymic lymphomas, 4 were diploid and 5 were aneuploid, with no chromosome-15-associated changes. Five lymphomas showed partial duplication of chromosome 15. Four of them have duplicated the segment distal to the C/DI breakpoint of T9H, while the 5th carried an interstitial duplication of the D2 sub-band of the T(7;15) translocation chromosome. These findings suggest that the duplication of the D 2/3 region, known to contain the c-myc and the pvt-I genes (Banerjee et al., 1985), rather than other regions of chromosome 15, contributes to the development and/or progression of murine T-cell leukemias.

Attempts to culture the parasitic stage of Dermatobia hominis (L. Jr.) in vitro (Diptera: Cuterebridae)

Dermatobia hominis larvae were cultured in a semidefined liquid medium. First-instar larvae (L1) grew well up to 44 days; 29.1% molted in a mean period of 8.62 days. Two larvae reached the third instar but lived only 1 and 18 days, respectively, after the second molt. The increase in size, measured in 4 larvae, was about 10-fold. Second- and third-instar larvae, obtained from the skin of cattle, survived and grew in the medium for up to 2 mo; 39.0% of the L2 molted while 77.3% of the L3 pupated, and some produced flies when transferred to sand after 14.84 +/- 10.08 days in the culture medium. Some maturation factor, obtained from the skin, may be necessary for the larvae to grow satisfactorily and to complete the full parasitic cycle in vitro.

[A model for the critique of undergraduate nursing curricula]

Trata-se de um ensaio teórico que tem por objetivo fornecer subsídio para efetivação de crítica aos currículos de Enfermagem. Identificou-se na revisão de literatura que os conceitos, avaliação, análise e crítica têm sido utilizados como sinônimos, e que na verdade a crítica de currículo de enfermagem não tem se constituído em objeto de estudo e conseqüentemente de preocupação. A escassez de abordagem do tema motivou as autoras a desenvolver uma proposta de crítica aos currículos de enfermagem a partir de suas experiências de vida bem como de suas concepções acerca de crítica e do que a mesma deve constar embora conscientes da pobreza científica de tal recurso.

Intestinal metaplasia and its variants in the gastric mucosa of Portuguese subjects: a comparative analysis of biopsy and gastrectomy material

The incidence and prevalence of intestinal metaplasia (IM) of three types were investigated in 1,041 endoscopic biopsy specimens collected from patients with gastric abnormalities in 1981 and 1982. Intestinal metaplasia was classified as type I (complete), type II (incomplete, sulfomucin-negative), or type III (incomplete, sulfomucin-positive). Intestinal metaplasia, found in 244 biopsy specimens (23%), was prevalent in gastric carcinoma (65%), compared with the incidence of 18.4 per cent in benign conditions. The sulfomucin-negative types I and II were more common than type III and were present in both benign conditions (98 per cent) and carcinoma (64 per cent). In contrast, type III IM was seen in only 12 per cent of IM-positive biopsy specimens, 90 per cent of which (26 of 29) were from patients with carcinoma. The high specificity of type III IM (98 per cent) might be acceptable for screening purposes, but its sensitivity of 36 per cent for gastric carcinoma is low. Two main factors would seem to account for the low sensitivity, as shown in the comparative analysis of IM types in gastrectomy specimens and the previous biopsy specimens from 93 patients: 1) sampling and 2) the association of type III IM with gastric carcinoma of the intestinal type but not with diffuse gastric carcinoma. The data thus confirm a significant relation between incomplete sulfomucin-secreting IM (type III) and gastric carcinoma of the intestinal type (P less than 0.001). This variant of IM should be considered a risk factor, and its presence in a biopsy specimen should prompt close surveillance.

[Glucose-6-phosphate dehydrogenase and succinate dehydrogenase in metastatic cells of Lewis lung carcinoma]

By the experimental model of the Lewis lung carcinoma we studied the activity of glucose-6-phosphate-dehydrogenesis (G6PDH) and succinic-dehydrogenesis (SDH) in the carcinoma itself, the lung metastases, the peripheral blood. A set of carcinoma, lung sections, peripheral blood smears were studied by histochemical techniques day by day since the 3rd day to the 15th one after the carcinoma grafting. The reported results allow us to conclude that G6PDH looks like a determinant of metastatic cell survival and growth and can be regarded as a marker of metastatic cells in the present model.