Approached Control Values Research Articles

Reversible Effects on B and T Cells of the Gut-Associated Lymphoid Tissues in Rats Malnourished during Suckling: Impaired Induction of the Immune Response to Intra-Peyer Patches Immunization with Cholera Toxin

To define the alterations provoked by malnutrition during suckling (20 pups/dam) in the gut-associated lymphoid tissues of rats, Peyer patch (PP) and mesenteric lymph node (MLN) cells were studied by flow cytometry. After weaning (21 days of age), rats malnourished during suckling (MNR) showed an increase in the CD4+CD45RC+subset together with a decrease in the CD4+CD45RC−subset (P< 0.01). These alterations remained even after 3 weeks of refeeding with stock diet. The CD4+CD8+subset was not increased in the MNR, indicating that a release of cortical thymocytes did not occur. At weaning the percentage of CD4+Thy1+cells was decreased in the MNR, indicating a low number of cells released from the thymus. When the B cell lineage was studied, we found a decreased percentage of precursors in the bone marrow and a decreased percentage of mature B cells in the periphery. When the MNR were inmunized intra-PP with cholera toxin (CT) after 1 week of refeeding, the specific IgG and IgA and IgM antibody-forming cells (measured by ELISPOT) were diminished in the PP, MLN, and spleen when compared to the age-matched controls (P< 0.001). These results were coincident with the ELISA titers obtained in the sera and in the intestinal fluids. When CT was administered after 2 weeks of refeeding, the number of IgM anti-toxin AFC approached control values, but the number of IgA and IgG AFC continued to be low. When 3 weeks of refeeding was allowed before the CT delivery, the immune response in the MNR aproached control values. These results indicate that malnutrition during suckling provokes alterations in B and T lymphocytes and produces a lack in the induction of the primary and secondary immune responses in the GALT which reversed after 3 weeks of refeeding.

Glutamate, glutamine and glutamine synthetase in the neonatal rat brain following hypoxia

Exposing 7-day-old rat pups to hypoxia, 8% oxygen/92% nitrogen, for 3 h alters glutamate (GLU), glutamine and glutamine synthetase (GS) activity in the striatum, frontal cortex and hippocampus. Immediately following the hypoxic insult there is a rapid transient elevation of GLU followed by a fall and then recovery to control values within 6 h. Glutamine content initially decreased after the termination of the insult, rose thereafter and approached control values within 6 h. GS activity was depressed after hypoxia and gradually returned to normal levels within 6 h. GS mRNA was increased in the three brain regions studied after hypoxia and returned to control values within 24 h. These results suggest that hypoxia alters GLU metabolism in the immature brain.

Deficient induction of the immune response to oral immunization with cholera toxin in malnourished rats during suckling

Malnourished rats during suckling were orally immunized with cholera toxin (CT) after different periods of refeeding. Intestinal fluids, sera, and supernatant fluids from cultured mesenteric lymph node (MLN) cells were obtained after rats were given three doses of CT and analyzed by enzyme-linked immunosorbent assay (ELISA) to evaluate the specific antibody response. Serum-specific immunoglobulin G (IgG), IgA, and IgM were severely diminished in malnourished rats immunized with three doses of CT after 1 week of refeeding when compared with those of controls. Also, a decreased IgA ELISA titer of the intestinal fluids and abrogation of the capacity to neutralize the CT in the intestinal ligated loop test were found. When a booster was given at 113 days of age, the immune response continued to be affected in the serum and the intestinal fluid. The results from the analysis of the supernatant fluids from cultured MLN cells were coincident with those mentioned above. When one dose of CT was administered into Peyer's patches (PP) after 1 week of refeeding, an impaired immune response was found in the intestinal fluid of malnourished rats during suckling compared with that of controls. This result together with the analysis of supernatant from MLN and PP cell cultures suggests that antigen triggering in the PP was affected. When the refeeding period was extended to 30 days and then the first dose of CT was administered, the antibody immune responses in intestinal fluid serum and supernatant fluid approached control values. These observations reinforce the fact that the gut-associated lymphoid tissue immaturity of the rats when they received the first CT dose (at 28 days old) was the main reason for the decreased immune response observed in the experimental group.

Time course of miniature currents in regenerating neuromuscular junctions of the cockroach Periplaneta americana

Miniature excitatory junctional currents in regenerating neuromascular junctions have been recorded from the devervated leg muscle fibers of the cockroach, Periplaneta americana with an external focal electrode. Miniature currents first reappeared after 21 days after denervation at 26°C. These currents occurred at a lower frequency and had a slower time course than miniature currents at normal junctions. The decay time constant of the falling phase of the earliest current was more than twice the control and the mean amplitude was less than half of the control. The decay time constant of the currents became shorter and their amplitude increased with increasing time after regeneration and approached control values at about 60 days after crushing the nerve. During regeneration of neuromuscular junctions, the falling phase of the miniature currents was always along a single exponential just as in the control. The observed change in the decay time constant of the currents suggests that the open time of the overall population of synaptic receptor-channels increases after denervation and returns to the control with time.

Glutamate receptor gene expression in spinal cord of arthritic rats

Injury to peripheral tissue leads to hyperalgesia that appears to be partly mediated by functional changes at the level of the spinal cord. Glutamate receptors are thought to play a role in acute and short-term (minutes to hours) spinal cord nociceptive responses and may be involved in prolonged or chronic pain (hours to days). We used in situ hybridization to examine AMPA/kainate (GluR1, GluR2, and GluR3) and NMDA (NR1) receptor gene expression in spinal cord following induction of prolonged inflammation by a unilateral intraarticular injection of lipopolysaccharide (LPS; 10 micrograms) into the hindpaw. In control rats, GluR1 expression was prominent throughout the layers of the gray matter of the spinal cord. Microscopic examination revealed labeling of neuronal cell somata in all major nuclei. GluR2 was abundant in substantia gelatinosa and motor nuclei; emulsion-dipped sections exhibited intense labeling over densely packed neurons in the superficial laminae of dorsal horn and individual motoneurons of ventral horn. GluR3 and NR1 were expressed at low levels throughout spinal cord gray matter. One day after LPS injection, when joint swelling was maximal, GluR1 expression was bilaterally decreased by 25% in the substantia gelatinosa at the level of the lumbar cord. In contrast, no significant change was apparent in GluR2, GluR3, or NR1 expression in any nucleus of the cord. At 72 hr after injection, when joint diameter approached control values, all four transcripts were expressed at near control levels. These findings provide evidence for a specific decrease in GluR1 expression in the cord in response to joint inflammation.

The effects of cisplatin on the incorporation of fresh syngeneic and frozen allogeneic cortical bone grafts

Allograft transplantation with concomitant chemotherapy has proven successful in the treatment of malignant bone tumors. However, these chemotherapeutic agents may delay tissue healing, resulting in clinical complications. To clarify the effects of cisplatin on the healing of bone grafts, we studied the incorporation of stably fixed massive diaphyseal femoral syngeneic and allogeneic grafts in rats treated with cisplatin. These data were compared with those of historical controls from animals that did not receive cisplatin. Rats that were to receive a fresh syngeneic graft or frozen allogeneic graft were given cisplatin every 4 weeks starting 9 weeks preoperatively and continuing until the time of death. The total bone area of the graft in animals that received cisplatin was smaller than that of the graft in untreated control rats that did not receive cisplatin. The area of the frozen allograft did not increase between 2 and 4 months. Revascularization was incomplete in cisplatin-treated groups at 2 months, but by 4 months, vessel ingrowth in fresh syngeneic grafts approached control values. Frozen allografts remained poorly revascularized at 4 months. Host-graft union was poor at 2 months in cisplatin-treated rats compared with controls. In cisplatin-treated rats, the host-graft union of the frozen allograft remained inferior at 4 months while that of the syngeneic graft improved. Allogeneic cortical bone grafts are incorporated more slowly and incompletely than syngeneic grafts, and this handicap is exacerbated by the administration of cisplatin.

Para-chlorophenylalanine treatment inhibits the expression of vasoactive intestinal peptide messenger RNA in rat anterior pituitary

Adult male Sprague-Dawley rats were treated with para-chlorophenylalanine (pCPA) or α-methyl tyrosine (α-MT) to study the effect of serotonin or catecholamine depletion on the expression of vasoactive intestinal peptide (VIP) messenger RNA in the anterior pituitary. Single injections of pCPA (300 mg/kg) for two consecutive days resulted on the third day in a dramatic depletion of serotonin in the medial basal hypothalamus, and a significant reduction in the pituitary content of VIP mRNA (1.0 and 1.7 kb). The effect of pCPA on VIP mRNA appeared to be relatively specific for the anterior pituitary since VIP message levels in the cerebral cortex did not decrease. α-MT treatment, (150 mg/kg) for 2 consecutive days, reduced dopamine concentrations in the MBH but had no significant effect on pituitary VIP levels. In a time-course study, hypothalamic serotonin and pituitary VIP mRNA levels were significantly depressed 1–3 days after initiation of pCPA treatment; however, 12 days after pCPA treatment, serotonin concentrations in the hypothalamus approached control values and pituitary VIP mRNA content increased an average of 2-fold over control levels in an apparent rebound effect. pCPA-treated rats injected i.p. twice a day with 5-hydroxytryptophan (5-HTP; 50 mg/kg) experienced a partial reversal in the decline in the 1.7 kb VIP mRNA seen 24 h after the first pCPA injection. However, at 72 h, supplementation with 5-HTP did not prevent the pCPA-induced decreased of pituitary VIP mRNA. These data indicate that serotonergic pathways have a major role in the control of VIP mRNA expression in the rat anterior pituitary.

Healing of the medial collateral ligament following a triad injury: A biomechanical and histological study of the knee in rabbits

The effect of a partial medial meniscectomy and anterior cruciate ligament (ACL) transection on medial collateral ligament (MCL) healing was studied in skeletally mature rabbits. Two groups of animals, group I (isolated MCL rupture) and group II (MCL rupture with ACL transection and partial medial meniscectomy), were examined. At 6 and 12 weeks postoperatively, histological examination of the healing MCL and biomechanical evaluation of the varus-valgus (V-V) knee rotation and tensile properties of the femur-MCL-tibia complex (FMTC) were performed. Group II animals experienced substantial joint degeneration by 6 weeks. Progressive osteophyte formation was observed adjacent to the MCL insertions along with proximal migration of the MCL tibial insertion between 6 and 12 weeks. Histologic examination of the healing MCL substance from both groups showed disorganized collagen, inflammation, and fibroblast proliferation that decreased over time. For group II knees, the V-V knee rotation was found to be significantly elevated (4.7 to 5.2 times the contralateral control), and did not decrease with time. In contrast, the V-V knee rotations of the group I specimens were 1.8 times greater than control immediately following injury, and approached control values by 12 weeks. Tensile testing of the FMTCs revealed that the ultimate load increased with time for both groups, but group I had significantly higher values than group II. The linear stiffness in group I was not different than that group II and did not increase with time. For the mechanical (material) properties of the healed MCL substance, the modulus of the healing tissue for group II was only 40% that of group I. The structural properties of the FMTC and the mechanical properties of the MCL substance from both groups at 6 and 12 weeks were significantly different from the contralateral controls. We further demonstrated that immediately after ACL reconstruction, the V-V rotation of group II knees could be restored to group I levels. Recent clinical studies of MCL healing following isolated complete ligament tears have suggested that nonoperative management without immobilization leads to excellent treatment outcome. However, in more severe injuries involving additional tissues, poor quality of the healed ligament tissue and articular degeneration are observed. Our results demonstrate the deleterious effects of an untreated triad injury on the healing of the MCL substance and its insertions. Examination of the MCL substance suggests that a much larger healing mass is formed following a triad injury, which partially compensates for inferior ligament mechanical properties.(ABSTRACT TRUNCATED AT 400 WORDS)

The proportion of galanin-immunoreactive neurons in mouse trigeminal ganglia is transiently increased following corneal inoculation of herpes simplex virus type-1.

To investigate whether neurobiological functions are modified by viral infection, we inoculated mouse corneas with herpes simplex virus type 1 (HSV-1) and examined neuronal galanin content in trigeminal ganglia at selected survival times. HSV-1 antigen appeared in neurons at day 3, peaked at day 6 and disappeared by day 11. Increased galanin positivity was first seen at day 6, peaked at day 10 and approached control values by day 21. This result provides further evidence that the biological program of peripheral sensory neurons is modified by herpes-virus infection.

Phagocytosis and adhesiveness of peripheral blood polymorphonuclear leukocytes in patients with rapidly progressive periodontitis

Phagocytosis and adhesiveness of peripheral blood polymorphonuclear leukocytes were studied in patients diagnosed with generalized rapidly progressive (form A) periodontitis. All patients belonged to a single family and were first degree relatives. In the patients' leukocytes there was a statistically significant reduction in phagocytic index and adhesiveness, in comparison with leukocytes from controls. However, adhesiveness approached control values in the presence of autologous serum, thus implying that serologic factors may enhance this function in patients with this type of periodontitis.

The response of the rat liver in situ to bromobenzene— In vivo proton magnetic resonance imaging and 31P magnetic resonance spectroscopy studies

Proton magnetic resonance imaging (MRI) and 31P magnetic resonance spectroscopy (MRS) have been used to study the response of the rat liver in situ to bromobenzene, a classic hepatotoxicant. A localized region of high proton signal intensity was seen in the perihilar region of the liver 24 hr after injection of a sublethal dose of bromobenzene. The signal intensity of the entire liver was increased at 48 hr with a gradual return approaching control values by 120 hr. These results are consistent with acute hepatic edema followed by repair of the damaged tissue. In vivo 31P MRS studies of the same rat livers were performed under conditions whereby localized, quantitative spectra could be obtained without surgical intervention. Initial concentrations of the major endogenous phosphorus-containing metabolites within the livers of control rats were 2.97 ± 0.43 m m for the phosphomonoesters (PME), 2.92 ± 0.56 m m for inorganic phosphate, 11.3 ± 1.0 m m for phosphodiesters (PDE), 4.09 ± 0.54 m m for ATP, and 0.56 ± 0.50 m m for ADP and the intracellular pH was 7.39 ± 0.14 (mean ± SD, n = 10). Bromobenzene was found to cause statistically significant ( p < 0.05) changes in several of these metabolites: a decrease in hepatic ATP levels (20% at 24 hr; 27% at 48 hr), a decrease in PDE levels (15% at 24 hr; 18% at 48 hr), and an increase in the PME (63% at 24 hr; 84% at 48 hr). Both the proton MRI and the 31P MRS changes have an onset of 15–20 hr and maximum effect at 25–60 hr, but the MRS changes returned to normal well before the MRI changes. The decreased ATP levels indicate deleterious effects of bromobenzene on the bioenergetic status of the liver in situ, while the increase PME, due to a selective increase in phosphocholine, suggests the activation of a phosphatidylcholine-specific phospholipase C in response to tissue damage. Trolox C, a potent inhibitor of lipid peroxidation, prevented the bromobenzene-induced hepatic edema (i.e., the increase in proton MRI signal intensity) and the bioenergetic deterioration (i.e., the decrease in ATP levels). However, the bromobenzene-induced increase in PME levels was not prevented by Trolox C. These results indicate that the process of lipid peroxidation plays a significant role in the hepatotoxicity of bromobenzene within the intact animal.

Diabetic parameters 58 weeks after injection with streptozotocin in rats fed basal diets or diets supplemented with fiber, minerals and vitamins

Streptozotocin injected rats provide useful models for studying the interaction of diet and diabetes, yet previous trials in rodents have focused primarily on protective effects of high protein-low carbohydrate formulations. Recent studies in control of diabetes in humans, however, recommend liberalization of carbohydrates and increased fiber consumption. In this investigation lasting for more than 1 yr, we formulated rations incorporating recommendations from human studies with 2 groups of streptozotocin-treated rats (50 mg/kg b.w.) and appropriate buffer injected controls. Rats were fed either a Purina basal diet or a Purina enriched diet having 2x the fiber, 3x the minerals and 4x the vitamins, as well as only about 80% of the caloric content of basal. Comparisons after 58 weeks showed similar survival rates (45% for enriched and 42% for basal) as well as similar weight gains. Both groups of streptozotocin injected rats gained weight steadily after an initial decline. Cataracts developed in almost all rats; however, appearance was slower in enriched diet fed animals. Renal tumors, a well known consequence of streptozotocin injection, appeared in at least 70% of treated rats regardless of diet. Glucose and glycated hemoglobin levels in plasma were reduced in enriched diet rats. Glycated hemoglobin concentration in the blood reached a maximum 30 wks after streptozotocin injection and declined thereafter. However, large variation in glucose and glycated hemoglobin were noted between rats, within and between groups. In some animals, these parameters approached control values after 50 wks, more so, but not exclusively, in rats fed the enriched diet. Insulin was elevated in enriched diet-fed rats, as was pancreatic function, suggesting regeneration of β cells. Differences in diabetic parameters, however, were less apparent when the fewer number of surviving rats were compared at 65 wks of age. The principle finding of this study was a diet with increased fiber, minerals and vitamins should be recognized as having similar beneficial effects in control of diabetes in long term rodent studies, as does a diet based on high protein and low carbohydrate.

Cerebral Polyamine Metabolism in Reversible Hypoglycemia of Rat: Relationship to Energy Metabolites and Calcium

Thirty minutes of insulin-induced reversible hypoglycemic coma (defined in terms of cessation of EEG activity) was produced in anesthetized rats. At the end of the hypoglycemic coma or after recovery for 3, 24, or 72 h induced by glucose infusion, the animals were reanesthetized and their brains frozen in situ. Two control groups were used: untreated controls without prior manipulations, and insulin controls, which received injections of insulin followed by glucose infusion to maintain blood glucose within the physiological range. The brains of these latter animals were frozen 3, 24, or 72 h after glucose infusion. Tissue samples from the cortex, striatum, hippocampus, and thalamus were taken to measure ornithine decarboxylase (ODC) activity, and putrescine and spermidine levels, as well as phosphocreatine (PCr), ATP, glucose, and lactate content. In addition, 20-microns thick coronal sections taken from the striatum and dorsal hippocampus were used for histological evaluation of cell damage and also stained for calcium. Insulin in the absence of hypoglycemia produced a significant increase in ODC activity and putrescine level but had no effect on the profiles of energy metabolites or spermidine. During hypoglycemic coma, brain PCr, ATP, glucose, and lactate levels were sharply reduced, as expected. Energy metabolites normalized after 3 h of recovery. In the striatum, significant secondary decreases in PCr and ATP contents and rises in glucose and lactate levels were observed after 24 h of recovery. ODC activity, and putrescine and spermidine levels were unchanged during hypoglycemic coma. After 3 h of recovery, ODC activity increased markedly throughout the brain, except in the striatum. After 24 h of recovery, ODC activity decreased and approached control values 2 days later. Putrescine levels increased significantly throughout the brain after reversible hypoglycemic coma, the highest values observed after 24 h of recovery (p less than or equal to 0.001, compared with controls). After 72 h of recovery, putrescine levels decreased, but still significantly exceeded control values. Reversible hypoglycemic coma did not produce significant changes in regional spermidine levels except in the striatum, where an approximately 30% increase was observed after 3 and 72 h of recovery (p less than or equal to 0.01 and p less than or equal to 0.05, respectively). Twenty-four hours after hypoglycemic coma, intense calcium staining was apparent in layer III of the cerebral cortex, the lateral striatum, and the crest of the dentate gyrus. After 72 h of recovery, the intense calcium staining included also cortical layer II, the septal nuclei, the subiculum, and the hippocampal CA1-subfield.(ABSTRACT TRUNCATED AT 400 WORDS)

Sodium bis(hydroxyethyl)dithiocarbamate reduces acute lung tissue damage induced by cadmium in rats

The protective effect of three dithiocarbamates against lung tissue damage induced by a single intratracheal instillation of cadmium chloride was examined in rats. The relative efficacy of these compounds was tested by comparing characteristic features of lung tissue damage: the increase of lung weight, and the changes in the synthesis and content of structural proteins. Of three compounds administered intraperitoneally at a dose of 2.46 mmol/kg body weight, the most effective in suppressing lung damage was sodium bis(hydroxyethyl)dithiocarbamate (DEDTC). Its efficacy was dependent on the time interval between administration of cadmium chloride and the DEDTC. The parameters of lung tissue damage which were examined approached control values when DEDTC and cadmium chloride were administered simultaneously.

Expression of Glial Fibrillary Acidic Protein and Neurofilament mRNA in Gliosis Induced by Experimental Autoimmune Encephalomyelitis

We have previously shown that the content of glial fibrillary acidic protein (GFAP) gradually increases in the spinal cord of Lewis rats with acute experimental autoimmune encephalomyelitis (EAE), reaching a level 1.5-2 times greater than that in controls by 35 days postimmunization (dpi). We report here that the increase in GFAP mRNA level followed a completely different time course and reached higher levels relative to controls than did that of the protein. Total RNA was isolated using a modified version of current methods using phenol/chloroform extractions to ensure optimal recovery from spinal cord. Control animals yielded 323 +/- 35 micrograms (mean +/- SD; n = 34) of total RNA/spinal cord throughout the experimental period. EAE animals contained up to three times as much total RNA during 11-14 dpi, a finding largely reflecting the infiltration of inflammatory cells. By 65 dpi, total RNA levels closely approached control values. As early as 10 dpi, increased amounts of GFAP mRNA were detected in EAE animals relative to controls. During 11-14 dpi, GFAP mRNA levels reached six- to eightfold greater than values in controls and then slowly declined throughout the remainder of the time course, with a fourfold increase still detected at 65 dpi. However, coinciding with the height of inflammation and clinical signs at 12 dpi, the GFAP mRNA content dropped to approximately 50% of the level at 11 dpi but rose again at 13 dpi. This dip was mirrored by a similar decrease in neurofilament mRNA content, but otherwise the level of this message remained relatively constant and equal to that in controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in water status and ABA content in peach leaves following foliar application of CGA 15281

A single foliar application of the ethylene (C 2H 4) releasing compound (2-chloroethyl)-methylbis(phenylmethoxy)silane (CGA 15281) to mature peach trees ( Prunus persica (L.) Batsch, cultivar ‘Redhaven’) was followed by increased evolution of C 2H 4 owing to degradation of the chemical. The highest rate of C 2H 4 evolution occurred 2 h after treatment, then declined rapidly approaching control values at 48–72 h. A marked increase in endogenous abscisic acid (ABA) noted 2 h after treatment was the earliest change detected in the leaves, while stomatal conductance and transpiration decreased within 4 h after treatment. Concurrent changes in the water potential were closely related to changes in stomatal conductance. Restrictions in assimilate production brought about by a synergistic action of ABA and C 2H 4 might be a significant factor in hastening abscission of leaves and fruits.

Regulation of Nerve Growth Factor (NGF) Synthesis in the Rat Central Nervous System: Comparison between the Effects of Interleukin-1 and Various Growth Factors in Astrocyte Cultures and in vivo.

In order to obtain information on the physiological regulation of NGF-synthesis in the central nervous system (CNS) we investigated the effects of a series of growth factors (known to be present in the CNS) in cultures of purified rat astrocytes and compared these effects with those observed after intraventricular injection of the same molecules. After preliminary experiments had shown that 10% fetal calf serum (FCS) produced a marked increase in NGF-mRNA levels in astrocytes (but neither in microglia nor oligodendrocytes) as demonstrated by Northern blot analysis and in situ hybridization the experiments were performed at low (0.5%) FCS concentrations. Supramaximal concentrations of IL-1 and various growth factors caused a 5- to 7-fold increase in NGF-mRNA after 6 h. By 24 h the NGF-mRNA levels approached control values again, most probably due to inactivation of the added factors since after readdition after 24 h the response was about the same as the initial one. Norepinephrine and 8-bromo-cAMP did not change NGF-mRNA levels. The growth factor-mediated changes in NGF-mRNA levels in astrocyte cultures were not consistently reflected by the changes observed after intraventricular injection. IL-1 produced by far the largest increase in hippocampal NGF-mRNA after intraventricular injection. This large response to IL-1 could result from a positive feedback mechanism, since IL-1beta injection not only increases NGF-mRNA but also IL-1beta-mRNA in the hippocampus. The understanding of the physiological regulation of NGF synthesis in the CNS is the basis for a rational approach to its pharmacological modification. This, in turn, is an attractive alternative to the (long-term) infusion of NGF or the transplantation of NGF-secreting cells with the goal of providing trophic support to the cholinergic neurons of the basal forebrain nuclei. These neurons are consistently affected in the early stages of Alzheimer's disease, their impaired function being essentially responsible for the cognitive deficits.

NORMAL BRAIN TISSUE RESPONSE TO PHOTODYNAMIC THERAPY: HISTOLOGY, VASCULAR PERMEABILITY AND SPECIFIC GRAVITY

The response of photodynamic therapy on normal brain was investigated in 140 Fisher rats. The rats were injected i.p. with Photofrin II (12.5 mg/kg) and 48 h later the dural area over the frontal cortex was photoactivated with red light (630 +/- 1 nm) from an argon dye laser. Treatment was performed with optical energy densities of 140 and 70 J/cm2. Histopathology, vascular permeability and specific gravity measurements were conducted on different populations of rats at 4 h, 24 h, 72 h and 1 week after photodynamic therapy (PDT). Histopathology revealed similar gross and microscopic pathology associated with light energies of 70 and 140 J/cm2 after all time points. A large cerebral infarct approximately the size of the brain surface area treated, evolved 24 h following treatment. Evans blue extravasation indicated a small area of vascular permeability evident as early as 4 h following PDT treatment at both energy levels, with increasing permeability evident at later time points. Specific gravity measurements taken on a representative area of the lesion indicated a significant (P less than 0.01) amount of edema present at 24 h post treatment with a gradual reduction approaching control values over the time period of 1 week. The data indicate a significant amount of damage to normal brain from low PDT treatment doses.

Effects of Traumatic Brain Injury on Arachidonic Acid Metabolism and Brain Water Content in the Rat

During the past decade, it has become increasingly clear that central nervous system trauma may produce tissue injury through both direct and indirect mechanisms.' Direct effects occur acutely as a result of mechanical disruption, with subsequent rapid cell death. Indirect effects are delayed and develop over a period of minutes to hours following the initial trauma. A variety of biochemical and physiological changes have been postulated to contribute to this delayed, secondary injury process, including: alterations in lipid metabolism: disruption of magnesium ion homeo~tasis,~ and edema formation! In the present study, preliminary results on changes in tissue lipids, magnesium, and edema following experimental traumatic brain injury to rats5 are reported. Any statistically significant differences among the control and experimental groups were determined by analysis of variance (ANOVA) with a Dunnett's posthoc test (* = significantly different from controls, p 5 0.05). Tissue levels of free fatty acids (FFA), total phospholipid, cholesterol, thromboxane B2, and water content were measured over time in the brains of rats subjected to fluid-percussion traumatic brain injury of moderate severity (2.0-2.2 atmospheres). Brains of injured animals and sham-operated controls were frozen in situ with liquid N2 at 10 min, 4 h, and 24 h postinjury, and the area that has been shown histologically to be the site of maximal injury (left parietal cortex) was dissected out. Trauma resulted in small increases in FFA levels a t the site of injury a t 10 min and 4 h, and much larger increases a t 24 h. Among the FFA, the largest increases were observed in stearate (control = 1.5 k 0.1, 10 rnin = 6.9 k 0.1*, 4 h = 7.4 * Oh*, 24 h = 17 .3 f 1 . 1 * pg/mg protein) arachidonate (control = 0.1 f 0.01, 10 rnin = 0.6 + 0.02*, 4 hr = 1.2 + 0.1*, 24 hr = 2.4 f 0.2*) and docosahexaenoate (control = 0.1 * 0.01, 10 rnin = 0.1 + 0.01, 4 h = 1 . 1 f 0.1*, 24 h = 2.7 * 0.2*). Total brain phospholipid and cholesterol levels were significantly decreased at all postinjury time points studied. Thromboxane levels were markedly elevated a t 10 min postinjury, substantially declined by 4 h, and approached control values a t 24 h (control = 8.7 * 2.8, 10 rnin = 636.4 8.3 33.1, 4 h = 110.8 11.4, 24 hr = 18.1

Regulation of Sertoli Cell Differentiated Function: Testicular Transferrin and Androgen-Binding Protein Expression*

The regulation of Sertoli cell function was investigated through an examination of the effects of various hormones, regulatory agents, and culture conditions on testicular transferrin and androgen-binding protein (ABP) synthesis and steady state levels of mRNA. FSH stimulated both transferrin and ABP production 2-fold above control levels. Interestingly, FSH had a differential effect on transferrin and ABP mRNA levels, with 1.25- and 2.0-fold respective increases in steady state levels of mRNA. Insulin and retinol stimulated both transferrin and ABP synthesis in a similar manner. Testosterone had no significant effect on either transferrin or ABP mRNA levels or synthesis. Maximum stimulation of both transferrin and ABP production occurred when Sertoli cell cultures were treated with a combination of FSH, insulin, and retinol, which resulted in a greater than 4-fold stimulation of synthesis and 2-fold stimulation of gene expression. Optimal transferrin and ABP secretion occurred between days 4-6 of Sertoli cell culture and subsequently declined. Sertoli cell number decreased with time in culture, such that approximately a 50% loss of cells was observed after 10 days of culture. The responsiveness of Sertoli cells to regulatory agents was altered by cell density, with a maximum responsiveness achieved at a density of 12 micrograms DNA/2 cm2 for both transferrin and ABP. As the cell density deviated from this level the responsiveness of cells to regulatory agents decreased and approached control values. These observations indicate that the culture conditions and the method of data normalization are important parameters in an analysis of the hormonal regulation of Sertoli cell function. FSH actions on Sertoli cells increased both cellular and excreted cAMP levels but had no effect on cGMP levels. (Bu)2 cAMP affected transferrin and ABP mRNA levels and synthesis in a similar manner, with approximately a 3-fold increase in synthesis and a 1.5-fold increase in steady state levels of mRNA. The minimum and maximum effective concentrations of (Bu)2AMP for both proteins were 1 and 10 microM, respectively. Observations imply that regulatory agents that act via a cAMP-mediated signal transduction mechanism, such as FSH, will probably have similar actions on transferrin and ABP production. In addition, data obtained with insulin and retinol indicate that transferrin and ABP production can be similarly regulated with cAMP-independent signal transduction mechanisms. Results indicate that transferrin and ABP mRNA levels and synthesis are regulated in a coordinate manner with the regulatory agents and culture conditions evaluated.(ABSTRACT TRUNCATED AT 400 WORDS)