Posterior cingulate cortex: sensory and oculomotor properties of single neurons in behaving cat.

The posterior cingulate cortex of the cat is strongly linked to cortical areas with sensory and oculomotor functions. We have now recorded from feline posterior cingulate neurons in order to determine whether they are active in conjunction with sensory events and eye movements. The results described here are based on monitoring the electrical activity of 195 single neurons in the posterior cingulate cortex of three cats equipped with surgically implanted scleral search coils and trained to fixate visual targets. Posterior cingulate neurons carry tonic orbital position signals and are phasically active in conjunction with saccadic eye movements. Activity related to eye movements and gaze is attenuated but not abolished by the elimination of visual feedback. Posterior cingulate neurons also are responsive to visual, auditory, and somatosensory stimulation. Systematic testing with visual stimuli revealed that responses are sharply reduced due to refractoriness at rates of stimulation greater than a few per second. These results conform to the theory that posterior cingulate cortex is involved in processes underlying visuospatial cognition.     

Impact of the Nutrition for Life Program on Junior High Students in New York State

School-based nutrition education represents an important component in a national strategy for health promotion. This study evaluated the impact of a school-based nutrition teaching program, Nutrition For Life, on the nutrition knowledge, attitudes, and self-reported behavior of seventh and eighth grade students from New York State. Some 1,863 students in 103 randomly selected classes completed a paper and pencil test covering nutrition attitudes, behavior, and knowledge. Modest use of the teaching program (median use = 3 hours) was associated with modest but significant differences in nutrition attitude, behavior, and knowledge scores. Interactions among teacher assignment, nutrition teaching, and Nutrition For Life use explained significant variations in nutrition test scores. Additional exposure to the program was associated with significantly higher nutrition attitude and behavior scores in schools with a higher proportion of low-income students.     

Cholecystokinin induces c-fos expression in hypothalamic oxytocinergic neurons projecting to the dorsal vagal complex.

Systemic administration of cholecystokinin (CCK) decreases gastric motility and stimulates pituitary secretion of oxytocin (OT). Although peripheral OT does not affect gastric function, increasing evidence suggests that central OT secretion acting within the dorsal vagal complex (DVC) can alter gastric motility. To evaluate whether systemically administered CCK is capable of activating oxytocinergic neurons projecting to the DVC, we utilized fluorogold retrograde labeling from the DVC in combination with c-fos and OT immunocytochemical staining to quantitatively analyze paraventricular nucleus (PVN) neurons of rats following injection of CCK at a dose known to cause maximal pituitary OT secretion (100 micrograms/kg i.p.). Our results showed that 2320 +/- 63 PVN neurons were retrogradely labeled from the DVC; 146 +/- 21 (6.3%) of these contained OT, and these cells were predominantly located in the medial parvocellular subdivision of the PVN. Of all retrogradely labeled cells, 671 +/- 112 (28.9%) expressed c-fos after CCK stimulation, and 68 +/- 14 of these (10.1%) contained OT. Approximately 50% of the OT-containing neurons retrogradely labeled from the DVC stained positively for c-fos. Many magnocellular OT neurons in the PVN that were not retrogradely labeled from the DVC also expressed c-fos after CCK stimulation. These results demonstrate that parvocellular OT neurons projecting to the DVC are co-activated along with magnocellular OT neurons projecting to the pituitary following administration of a large dose of CCK, and lend support to a possible functional role for OT as a central neurotransmitter that modulates vagal efferent traffic to the gastrointestinal tract.     

Topographic organization of cortical and subcortical projections to posterior cingulate cortex in the cat: evidence for somatic, ocular, and complex subregions.

The posterior cingulate area (CGp) of the cat consists of cortex on the exposed cingulate gyrus and in the adjacent ventral bank of the splenial sulcus. We have placed deposits of distinguishable fluorescent tracers at multiple restricted sites in CGp and have analyzed the distribution throughout the forebrain of neurons labeled by retrograde transport. Cortical projections to CGp arise (in approximately descending order of strength) from anterior cingulate cortex; prefrontal cortex and premotor areas including the frontal eye fields; visual areas including especially areas 7 and 20b; parahippocampal areas; insular cortex; somesthetic areas; and auditory areas. Corticocortical pathways are organized topographically with respect to the posterior-anterior axis in CGp. Projections from prefrontal cortex and other areas with complex (as opposed to sensory, motor, or limbic) functions are concentrated posteriorly; projections from visual and oculomotor areas are concentrated at an intermediate level; and projections from areas with somesthetic and somatomotor functions are concentrated anteriorly. Thalamic projections to CGp arise from the anterior nuclei (AD, AV, and AM), from restricted portions of the ventral complex (VAd, VAm, and VMP), from discrete sectors of the lateral complex (LD, LPs, and LPm), from the rostral crescent of intralaminar nuclei (CM, PC, and CL), and from the reuniens nucleus. Projections from AM, VAd, LD, and LPs are spatially ordered in the sense that more ventral thalamic neurons project to more anterior cortical sites. Projections from AV and AD are stronger at more posterior cortical sites but do not show other signs of topographic ordering. Projections from LPm, CM, PC, CL, and RE are diffuse. We conclude (1) that cortical afferents of CGp derive predominantly from neocortical areas including those with well established sensory and motor functions; (2) that limbic projections to CGp originate primarily in structures, including the hippocampus, which are associated with memory, as opposed to structures, including the amygdala, which are associated with emotional and instinctual behavior; and (3) that CGp contains subregions in which complex, ocular, or somatic afferents predominate.     

Comparison of creatinine as determined with the Ames Seralyzer and by three Jaffé-based methods

We compared results for urinary creatinine, serum creatinine, and creatinine clearance, as determined with the Ames Seralyzer, with results determined with the Beckman ASTRA, the DuPont aca, and Technicon's AutoAnalyzer and SMAC. Results for urinary creatinine from the Seralyzer differed significantly (p less than 0.05) from those obtained with the ASTRA and AutoAnalyzer, but not with the aca. The Seralyzer results for serum creatinine were at least 1.0 mg/L higher (p less than 0.05) than by the other three methods. Results for creatinine clearance from the Seralyzer were 8 to 11 mL/min lower (p less than 0.05) than results by the other three methods. These differences are related to the positive interference by bilirubin in the Seralyzer creatinine method. We also evaluated 23 other compounds for interference with these methods for creatinine.     

Glomerular hyalinosis and its relation to hyperfiltration

Reduction in renal mass in rats results in hyperfiltration of the remnant nephrons, accompanied by injury to the glomeruli and their eventual sclerosis. This study was undertaken in a rat model with 5/6 reduction of renal mass to follow the evolution of glomerular damage, over an 11-week period, with particular emphasis on the widely prevalent, although seldom discussed, lesion of hyalinosis. Light, electron, and immunofluorescence microscopic studies were performed and blood pressure, excretion of urinary albumin, and serum creatinine levels determined. Systolic blood pressure, urinary albumin excretion, and serum creatinine levels were all increased by the third week following operation. Blood pressure and serum creatinine continued to increase throughout the period of study. Glomerular damage was focal and segmental, and glomeruli were equally affected in both the juxtamedullary and outer zones of the cortex. Endothelial injury was noted to be the first indicator of glomerular damage, followed closely by alterations in the epithelial cells. The early hyalinosis lesion was characterized by an accumulation of homogeneous electron-dense material beneath damaged endothelial cells with later encroachment on the capillary lumen resulting in the easily recognizable eosinophilic, periodic acid-Schiff-positive lesion by light microscopy. These alterations were accompanied by complex changes within the mesangium, including both mesangiosclerosis and mesangiolysis. Glomerular hyalinosis, glomerular sclerosis, vascular damage, blood pressure, and albuminuria were ranked in order of severity and the rankings subjected to multiple regression analysis. Significant correlations were present between glomerular sclerosis and hyalinosis, arterial damage and blood pressure, and hyalinosis and urinary albumin excretion. The hyalinosis lesion accompanying the progressive glomerular sclerosis in this model resembles that seen in a number of human conditions. In addition, the correlations of hyalinosis with glomerular sclerosis and albuminuria reflect its association with glomerular injury; it is likely that it will prove to be a reliable marker of hyperfiltration injury.     

Cytogenetic analysis of urologic malignancies: study of tumor colony forming cells and premature chromosome condensation

We have utilized a human tumor clonogenic assay to grow, and subsequently cytogenetically analyze, tumor colony forming cells from human urologic malignancies. Results following chromosome banding analysis are presented from 4 cases of transitional cell carcinoma and 1 case of renal cell carcinoma. Preliminary evidence suggests a possible association between the loss of chromosome 8 and progression or recurrence of transitional cell carcinoma. Additionally, we have utilized the technique of premature chromosome condensation to identify the interphase chromatin profile of urothelial cells obtained by cystoscopy from 8 patients with transitional cell carcinoma and compared these results to urothelial cells obtained from 7 control patients. This study demonstrates that cells obtained from urologic cancers contain a high proportion of cells in late G1, while normal urothelial cells are usually found in the early G1 phase of the cell cycle. Statistical correlation of premature chromosome condensation analysis suggests this method may be a useful adjunct to routine histopathology in discriminating between normal and cancerous urothelium.     

A pertussis toxin-sensitive GTP-binding protein in the human neutrophil regulates multiple receptors, calcium mobilization, and lectin-induced capping.

Human neutrophils treated with pertussis toxin had decreased functional responses to several agents including zymosan-treated serum, heat-aggregated immunoglobulin, platelet-activating factor, and fMet-Leu-Phe. Responses affected include superoxide generation and release of lysozyme. The degree and type of inhibition was dependent on the individual receptor and the cellular response studied. Measurement of intracellular calcium levels with quin-2 showed that both fMet-Leu-Phe- and platelet-activating factor-mediated increases in quin-2 fluorescence were diminished as a result of pertussis toxin treatment. fMet-Leu-Phe-mediated calcium uptake was also inhibited. However, under conditions where fMet-Leu-Phe-mediated effects on cell function were completely abolished, only a partial inhibition of 3,4,5-trimethoxybenzoic acid 8-(diethylamino)octyl ester (TMB-8) sensitive calcium uptake was observed. A study of the linked reactions of chemotaxis, capping, and shape change revealed that chemotaxis was inhibited regardless of the chemoattractant utilized (zymosan-treated serum, fMet-Leu-Phe, and platelet-activating factor) and the associated reactions of Con A capping and fMet-Leu-Phe- or Con A-mediated shape change were reduced in pertussis toxin-treated cells. Our results suggest that multiple mediators of inflammation act through a pertussis toxin-sensitive GTP-binding protein that regulates the mobilization of internal calcium as well as calcium uptake and is, in addition, a key control element of shape change, capping, and chemotaxis.     

Comparison of 26- and 27-G needles for spinal anesthesia for ambulatory surgery patients.

Seven hundred thirty ambulatory surgery patients, randomly assigned to receive spinal anesthesia with a 26- or 27-G needle, were studied for the incidence of post-dural puncture headache (PDPH), postoperative back pain, and patient acceptance. The incidence of PDPH following the use of 26- and 27-G needles was 9.6% and 1.5%, respectively (P less than 0.05). The incidence of PDPH was 5.7% among men and 13.4% among women following the use of 26-G needles (P less than 0.05), whereas no difference between men and women was noted after the use of 27-G needles. Of the patients who were 40 yr of age or younger, the overall incidence of PDPH was 11.9%, with a 7.5% incidence among men and a 16.4% among women following the use of 26-G needles (P less than 0.05) and a 1.8% incidence of PDPH following the use of 27-G needles, with no statistical difference between genders. Postoperative back pain was experienced in 18.3% of the patients in the 26-G group and 20.2% in the 27-G group (difference not significant). Favorable acceptance of spinal anesthesia was reported in 89.4% of patients in the 26-G group and 98.2% in the 27-G group (P less than 0.01). Results from this study demonstrate that, in patients who received spinal anesthesia for ambulatory surgery, the use of 27-G needles resulted in a significantly lower incidence of PDPH and greater patient acceptance compared with the use of 26-G needles. The incidence of postoperative back pain was not significantly different between the two groups.