Efferent connections of the medial prefrontal cortex in the rabbit

The different cytoarchitectonic regions of the medial prefrontal cortex (mPFC) have recently been shown to play divergent roles in associative learning in rabbits. To determine if these subareas of the mPFC, including areas 24 (anterior cingulate cortex), 25 (infralimbic cortex), and 32 (prelimbic cortex) have differential efferent connections with other cortical and subcortical areas in the rabbit, anterograde and retrograde tracing experiments were performed using thePhaseolus vulgaris leukoagglutinin (PHA-L), and horseradish peroxidase (HRP) techniques. All three areas showed local dorsal-ventral projections into each of the other areas, and a contralateral projection to the homologous area on the other side of the brain. All three also revealed a trajectory through the striatum, resulting in heavy innervation of the caudate nucleus, the claustrum, and a lighter projection to the agranular insular cortex. The thalamic projections of areas 24 and 32 were similar, but not identical, with projections to the mediodorsal nucleus (MD) and all of the midline nuclei. However, the primary thalamic projections from area 25 were to the intralaminar and midline nuclei. All three areas also projected to the ventromedial and to a lesser extent to the ventral posterior thalamic nuclei. Projections were also observed in the lateral hypothalamus, in an area just lateral to the descending limb of the fornix. Amygdala projections from areas 32 and 24 were primarily to the lateral, basolateral and basomedial nuclei, but area 25 also projected to the central nucleus. All three areas also showed projections to the midbrain periaqueductal central gray, median raphe nucleus, ventral tegmental area, substantia nigra, locus coeruleus and pontine nuclei. However, only areas 24 and the more dorsal portions of area 32 projected to the superior colliculus. Area 25 and the ventral portions of area 32 also showed a bilateral projection to the parabrachial nuclei and dorsal and ventral medulla. The dorsal portions of area 32, and all of area 24 were, however, devoid of these projections. It is suggested that these differential projections are responsible for the diverse roles that the cytoarchitectonic subfields of the mPFC have been demonstrated to play in associative learning.     

Observations on the process of degeneration of the afferent connections to the sensori-motor cortex of the monkey.

The ultrastructural features of degeneration of the afferent connections to the sensorimotor cortex of the primate have been studied with the electron microscope. Thalamo-cortical terminals show cytoplasmic darkening and swelling of vesicles, and neurofilaments and glycogen are often prominent in the larger terminals, although true neurofilamentous hypertrophy is rare. The terminals of the commissural and association projections similarly show darkening and some swelling of vesicles but are usually smaller and neurofilaments and glycogen are rarely seen. Ethanolic-phosphotungstic acid specifically stains degenerating axons and axon terminals. Degeneration occurs more rapidly in the terminals of the association projections than in those of the longer commissural projection although terminals at different stages of degeneration are present simultaneously in both instances. Micropinocytosis of degenerating terminals has been found and both glial and neuronal profiles are involved in this. Exposed post-synaptic thickenings have been seen and these induce subsurface cisternae in the neuronal structures to which they become apposed, including axon initial segments and unmyelinated axons.Damage to a part of the central nervous system thus causes consequential changes in other regions, and these changes are relevant to the interpretation of experimental studies and to the possibility of reorganization of connections following injury.     

Inactivation of the E-cadherin gene in sporadic diffuse-type gastric cancer.

Loss of the cell adhesion molecule E-cadherin has been observed in a variety of human carcinomas, and germline E-cadherin mutations have been found in several familial cases of diffuse gastric cancer. We sought to determine the prevalence and nature of E-cadherin alterations in "sporadic" gastric carcinomas. We performed comprehensive sequencing of the coding region, loss of heterozygosity (LOH) analysis, and immunohistochemical protein expression determination on 40 sporadic gastric adenocarcinomas. In total, 7 of 25 diffuse-type cancers harbored genetic alterations in the E-cadherin gene. Novel mutations predicted to significantly compromise protein function were found within 4 of these cancers, 2 of which harbored alterations resulting in biallelic inactivation of the gene product. Three diffuse cancers failed to amplify Exon 8 of E-cadherin, suggesting the presence of a homozygous abnormality. Notably, one germline E-cadherin mutation was also identified within these "sporadic" diffuse cancers. Significant gene mutations were not found in the 14 intestinal-type or histologically mixed cancer. Immunohistochemistry revealed aberrant or negative protein expression in seven diffuse-type tumors, four of which correlated with the genetic alterations. Both diffuse and intestinal-type tumors exhibited low rates of LOH, suggesting that allelic loss at the locus is not a common mechanism for E-cadherin inactivation during gastric tumorigenesis. Our observations suggest that inactivation of the E-cadherin gene occurs only in a subset of diffuse-type gastric cancers, as the majority of cases did not contain genetic alterations or identifiable protein abnormalities. Germline E-cadherin alterations, although rare, may underlie some diffuse gastric cancer cases that have important biologic and practical implications     

The salivary microbiota as a diagnostic indicator of oral cancer: A descriptive,non-randomized study of cancer-free and oral squamous cell carcinoma subjects

Background  

The purpose of the present investigation was to determine if the salivary counts of 40 common oral bacteria in subjects with an oral squamous cell carcinoma (OSCC) lesion would differ from those found in cancer-free (OSCC-free) controls.     

Interrupted versus continuous chemotherapy in patients with metastatic breast cancer. The Piedmont Oncology Association

BACKGROUND. Chemotherapy for metastatic breast cancer is palliative, and the optimal duration of therapy is unknown. We designed a trial to determine whether continuous treatment is superior to stopping treatment after a brief induction period and resuming treatment when the disease progresses. METHODS. We treated 250 women with metastatic breast cancer with six courses of cyclophosphamide, doxorubicin, and fluorouracil given every three weeks. At the completion of this induction period, women whose disease either regressed or remained stable were randomly assigned to receive either continued treatment with cyclophosphamide, methotrexate, and fluorouracil (maintenance therapy) or no further treatment (observation) followed by treatment with cyclophosphamide, methotrexate, and fluorouracil when disease progression became evident (reinduction). RESULTS. The combined rate of complete and partial responses after initial therapy was 30 percent (71 of 233 patients who could be evaluated; 95 percent confidence interval, 25 percent to 37 percent). In another 42 percent (98 patients), the disease remained stable. A total of 145 patients were randomized. Seventy-one were randomly assigned to the maintenance-therapy group, and 74 to the observation group. The median time to progression was 9.4 months for patients in the maintenance-therapy group and 3.2 months for patients in the observation group (P less than 0.001). After reinduction therapy, the median time to progression was 3.5 months. The median length of survival from the time of initial therapy was 14.8 months for all 250 patients; it was 21.1 months for the 71 patients in the maintenance-therapy group and 19.6 months for the 74 patients in the observation group (P = 0.67). Maintenance therapy was the most important determinant of the time before progression (P less than 0.001), but it was not associated with prolonged survival. The changes in performance status were similar in the patients in both groups, but nausea, vomiting, and mucositis were significantly more frequent in the maintenance-therapy group. CONCLUSIONS. In patients with breast cancer who received induction chemotherapy for 18 weeks, subsequent continuous chemotherapy was associated with a significant prolongation of the time before progression as compared with those receiving no further therapy; overall survival, however, was not significantly different in the two groups.     

Modification of surface composition of Actinomyces viscosus T14V and T14AV.

The morphology and serology of Actinomyces viscosus T14V and T14AV were compared. When grown in supplemented tryptic soy broth, the virulent strain (T14V) possessed an extensive network of cell surface fibrils. In this medium, the avirulent strain (T14AV) possessed a microcapsule, absent on strain T14V, and a comparatively small number of surface fibrils. Mild acid extraction (Lancefield procedure) solubilized common antigenic components on both strains as well as components detectable only in the virulent strain T14V (virulence-associated antigens 1 and 2). When grown in Socransky chemically defined medium or Carlsson complex medium, the avirulent strain possessed increased amounts of surface fibrils and virulence-associated antigens. Whole cells and extracts of avirulent cells grown in Socransky medium absorbed antibodies to virulence-associated antigens with approximately the same efficiency as did whole cells and extracts of strain T14V, suggesting antigenic similarity between the two cell types. The results strongly support the hypothesis that observable differences between A. viscosus strains T14V and T14AV represent quantitative, rather than qualitative, differences in particular cell surface components. In addition, the magnitude of these differences can be modified by changing growth conditions.     

Cephalometric analyses and flow-volume loops in obstructive sleep apnea patients

Fifteen patients with obstructive sleep apnea syndrome (OSAS) and 10 controls were studied. Polygraphic monitoring during sleep confirmed the presence or absence of OSAS. Ten OSAS patients and five controls had cephalometric analysis and 12 OSAS patients and five controls had a flow-volume loop study during wakefulness. Seven OSAS patients were submitted to both analyses. Flow-volume loops were unable to detect extrathoracic airway obstruction in six out of 12 OSAS patients. One control was found with positive results. Six out of seven subjects with positive flow-volume loops were overweight (greater than or equal to 30% ideal weight). Cephalograms were very useful in demonstrating mandibular deficiencies in OSAS patients. The length of the soft palate and the position of the hyoid bone, together with the measurement of the posterior airway space, are criteria of great interest in OSAS patients. Cephalometric analysis is recommended in all OSAS patients scheduled for surgical procedure. None of these tests, however, whether alone or in combination, is capable of identifying all cases of OSAS.