Decrease in cellular replicative potential in "giant" mice transfected with the bovine growth hormone gene correlates to shortened life span

Adult mice, (C57BL/6 x Sjl)F1 hybrids, transfected with the bovine growth hormone gene (bGH) grow to twice normal size, but have a mean life span less than 50% that of control siblings without the transgene. The replicative potentials of cells from six different tissue sites (tail skin and ear skin dermal fibroblasts, tail subdermal connective tissue fibroblasts, kidney medulla epithelial cells, bone marrow myofibroblasts, and spleen myofibroblasts) were assayed in vitro using clone size distribution analysis. Cells from all of the above bGH+ tissues produced a smaller fraction of large clones, relative to age-matched controls, in all of these cell types. The loss of replicative potential did not appear to be the result of negative conditioning of the cloning media by the bGH+ cells, and was tightly correlated to the period of accelerated growth in these animals (3-12 weeks), a time when additional GH receptors are expressed.

Microslicing of the resin-embedded cochlea in comparison with the surface preparation technique for analysis of hair cell number and morphology

The surface preparation technique for hair cell counting is frequently used for the analysis of cochlear pathology in relation to hearing impairment. To overcome problems encountered with standard surface preparation methods, a new combination of resin embedding and microslicing has been applied to the mammalian cochlea, to permit hair cell counting to be followed by electron microscopic analysis. Partial removal of the cochlear shell is followed by resin infiltration under vacuum prior to polymerization. The cochlea is then subdivided into hemicoils using a mounted annular diamond blade. Embedding before microslicing ensures that both apical and basal regions of the cochlea are preserved equally well with an evenly distributed and therefore predictable 10% hair cell loss. By comparison, the standard surface preparation method often produces distortion of remaining organ of Corti and unpredictable losses of hair cells, for example, up to 17%. The damage tends to be greatest towards the base of the cochlea, an area which shows particular susceptibility to ototoxic agents such as the aminoglycoside antibiotics. Thus, for assessment of pathology caused by ototoxic agents, this method has considerable advantages over the surface preparation technique.

Stimulus duration and the sensory memory trace: an event-related potential study

The mismatch negativity (MMN) of the auditory event-related potential is elicited when a stimulus deviates from that represented by the neural memory trace developed by preceding stimuli. The effect of stimulus duration on this trace was studied by presenting sequences of 1000 Hz, 80 dB stimuli to subjects engaged in silent reading. Stimuli were, in different blocks, either of 4, 10, 30, 100 or 300 ms in duration. 5% of the stimuli were deviants which were either higher in frequency (1050 Hz) or lower in intensity (70 dB) than the standards. The "silent" period between two successive stimuli was constant at 300 ms. The minimum stimulus duration with which a distinct MMN was elicited by frequency deviants was 30 ms, but the MMN amplitude was not increased when stimulus duration was further prolonged. In contrast, the intensity MMN was elicited even when stimulus duration of 10 ms and its amplitude increased as a function of stimulus duration. Reaction times and hit percentages in response to these deviant stimuli in a separate discrimination task displayed analogous patterns of results.

An age-related reduction in the replicative capacity of two murine hematopoietic stroma cell types

Two stromal cell types, myofibroblasts and endothelial-like cells, that were identifiable by structural and antigenic specificities, were obtained from murine bone marrow and spleen of young, middle-aged, and old mice of two strains and sexes and grown in liquid culture for 9 or 10 days. As expected, there were more total nucleated cells per organ in the old mice (with larger organs) than in the young mice. However, the concentration of stromal colony forming cells was greater in the young mice, resulting in the number of colony forming cells per organ not being significantly different in most comparisons. The in vitro replicative capacity of the two stromal cell types from both organs in all age groups was determined by clone size distribution assays. In all instances the number of cell doublings achieved was statistically significantly greater in the stromal cell clones from young mice than those from old mice. The cell doubling capacity of the middle-aged mice fell between that of the young and the old mice and in most instances that difference was also statistically significant. It was concluded that these in vitro findings constituted a biomarker of aging in these tissues and that this was significant in relation to previous in vivo and in vitro work by these authors and by others reporting the inferiority of aged bone marrow and spleen stroma to regenerate and to support hematopoiesis.

[Mechanism of neuronal damage caused by cerebral ischemia]

After the middle cerebral artery of rats was occluded, changes in the content of 14 free amino acids and the activity of antioxidant enzymes in the ischemic striatum were assessed with respect to the duration of ischemia. Glu and Asp levels were significantly reduced by 60 min of ischemia, GABA was increased by 30 and 60 min and Ala was increased by 5, 15, and 30 min. During ischemia, the levels of striatal Gln, Asn, Ser, Tau, Gly and Pro were found to be normal. In comparison with the sham-operated rats, the changes in the content of Thr, His, Arg and Tyr were inconclusive, since the effect of operative stress could not be ruled out on such occasion. Concomitantly, the Zn-Cu superoxide dismutase and glutathione peroxidase activity were significantly reduced by 30 min of ischemia. It revealed that the reduced capacity to scavenge the oxygen free radicals occurred during the early stage of cerebral ischemia. The above changes of Glu, Gln, GABA and Pro level might be considered as the final outcome of the decrease of glutamate synthesis, the acceleration of its conversion to GABA, and the extracellular leakage of glutamate. According to our data, the oxygen free radicals might be involved in the evolution of primary neuronal damage at the ischemic striatum.

Predictors of Two Obesity Complications: diabetes and hypertension

Gender, age, waist-hip ratio (WHR) and body mass index (BMI) have been reported to herald two complications of obesity: diabetes or hypertension. Most literature is based on patient populations with mean BMIs ranging from 22 to 35 kg/m(2). This study population of severely obese patients selected for surgical treatment of obesity had a mean age of 37 +/- 9.4 years, median WHR of 0.9 (0.4-2.1) and median BMI of 44.0 (29-89) kg/m(2). It was found that age, WHR and BMI were significant predictors for diabetes or hypertension. Gender was not found to be a significant predictor for either diabetes or hypertension. A mathematical model was used to calculate the predictive probability of developing diabetes or hypertension using age, BMI and WHR.

[Epilepsy and hypohaptoglobinemia]

The serum haptoglobin (Hp) of 24 patients with familial epilepsy and 21 relatives of them, as well as 21 patients with secondary epilepsy was determined by the method of linear concentration gradient (4-22%) polyacrylamide gel electrophoresis. The mean value of their serum Hp was significantly reduced to 54.83% (P less than 0.001), 76.48% (P less than 0.01) and 74.91% (P less than 0.01) of that of the control (109.63 mgHb/dl, n = 201) respectively. The possible pathophysiological mechanism of the epileptic seizures and reduced serum Hp level was discussed briefly.

Immune response to Moloney murine leukemia virus nonviral, tumor-associated antigens fails to provide in vivo tumor protection

Two distinct populations of CTL have previously been shown to be generated in lymphocyte cultures derived from the spleens of C57BL/6 mice that have rejected Moloney murine leukemia virus:Moloney sarcoma virus (MoMuLV:MSV)-induced tumors. One population is specific for MoMuLV viral Ag whereas the other appears to be directed against a nonviral, tumor-associated Ag (TAA). Using a virus-negative variant of the MoMuLV-induced lymphoma MBL-2 that has retained the expression of the MuLV:TAA, we attempted to further characterize the MuLV:TAA-specific CTL population. First, this same pattern of CTL reactivity was observed using a variety of immunization protocols indicating that the TAA-specific CTL population was not an artifact of the original immunization protocol but was a reproducible component of the MoMuLV CTL response. Moreover, CTL precursor frequency analysis indicates that the MuLV:TAA-specific CTL represent approximately 60% of the CTL detected in in vitro cytotoxicity assays. However, when the role of MuLV:TAA CTL in the in vivo rejection of MoMuLV-induced tumors was examined, no role for the MuLV:TAA-specific CTL response could be determined. Immunization protocols that had been shown to give rise to both CTL populations were capable of protecting mice from tumor development after a challenge with the parental MBL-2 tumor cell line but not the virus-negative variant MBLv cell line. In addition, immunization with the variant, shown to give rise to only MuLV:TAA-specific CTL capable of lysing both MBL-2 and MBLv in vitro, failed to protect mice from a tumor challenge of either cell type.

Immune response to Moloney murine leukemia virus nonviral, tumor-associated antigens fails to provide in vivo tumor protection

Two distinct populations of CTL have previously been shown to be generated in lymphocyte cultures derived from the spleens of C57BL/6 mice that have rejected Moloney murine leukemia virus:Moloney sarcoma virus (MoMuLV:MSV)-induced tumors. One population is specific for MoMuLV viral Ag whereas the other appears to be directed against a nonviral, tumor-associated Ag (TAA). Using a virus-negative variant of the MoMuLV-induced lymphoma MBL-2 that has retained the expression of the MuLV:TAA, we attempted to further characterize the MuLV:TAA-specific CTL population. First, this same pattern of CTL reactivity was observed using a variety of immunization protocols indicating that the TAA-specific CTL population was not an artifact of the original immunization protocol but was a reproducible component of the MoMuLV CTL response. Moreover, CTL precursor frequency analysis indicates that the MuLV:TAA-specific CTL represent approximately 60% of the CTL detected in in vitro cytotoxicity assays. However, when the role of MuLV:TAA CTL in the in vivo rejection of MoMuLV-induced tumors was examined, no role for the MuLV:TAA-specific CTL response could be determined. Immunization protocols that had been shown to give rise to both CTL populations were capable of protecting mice from tumor development after a challenge with the parental MBL-2 tumor cell line but not the virus-negative variant MBLv cell line. In addition, immunization with the variant, shown to give rise to only MuLV:TAA-specific CTL capable of lysing both MBL-2 and MBLv in vitro, failed to protect mice from a tumor challenge of either cell type.

Perioperative risks and safety of surgery for severe obesity

The National Bariatric Surgery Registry (NBSR) results reflect low perioperative risk for obesity surgery. Five deaths occurred within 40 d of operation in 5178 patients (0.1%). A subset of 3174 patients with complete information for complication and postoperative hospital stay was further studied. Females comprised 87% of the data set. Median values were determined for age, 37 y (18-70 y); operative weight, 121 kg (77-288 kg); and operative body mass index (BMI), 44 kg/m2 (29-91 kg/m2). Patients with no complications (89.7%) were reported to have a median postoperative stay of 4 d (2-23 d). The most severe complications were deep venous thrombosis (0.3%) and gastrointestinal leak (0.6%), with median postoperative hospital stay of 12 d (ranges 2-27 and 4-59 d, respectively). The most frequent complication reported was respiratory (4.5%), with median postoperative stay of 6 d (3-34 d). Median postoperative hospital stay for wound infection (1.6%) was 5 d.

Weight Loss Curve Analysis

The purpose of this study was to develop a mathematical model to describe weight loss trend over time and to determine differences, if any, among various weight loss trends. Weight change was studied following Roux-en-Y gastric bypass (RGB) and vertical banded gastroplasty (VBG). The total number of patients analyzed was 3172, 63.5% VBG and 36.5% RGB. Median age (years) for VBG was 36 (range 18-70) and RGB 38 (range 18-66). Median operative body mass index (BMI) (kg/m(2)) for VBG was 45.0 (range 30.1-90.5) and RGB 43.3 (range 30.4-80.6). Females represented 87% of the VBG patients and 89% of RGB patients. Obesity category percentages for each operative type were: super-VBG 20%, RGB 14%; morbid-VBG 78%, RGB 80%; obese-VBG 2%, RBG 6%. The development of a mathematical model to study weight loss over time was a two-stage process. First, weight loss trend was determined as evidenced by individual patient BMI values plotted over time. It was observed that plots represented quadratic curves, so the model BMI = B&inf0; + B&inf1;(time) + B&inf2;(time)(2) was used. Second, the estimated beta's (B&inf0;, B&inf1;, B&inf2;) were treated as response variables to estimate weight loss trend for the combination effect of three independent variables: gender (male and female), obesity category (super, morbid, obese) and operative type (VBG and RGB). It was found that the three independent variables simultaneously interact with patient weight loss (p = 0.0001).

[Effect of 6-hydroxydopamine on cerebral catecholamines, lipid peroxidation and antioxidant enzymes in rats-concerned with pathogenesis of Parkinson's disease]

As an animal model of human Parkinson's disease 250 micrograms of 6-Hydroxydopamine was injected intraventricularly in the rats. At 24 h, 48 h, 7th and 14th day after injection, the levels of dopamine, norepinephrine, Cu, Zn- and Mn- superoxide dismutase (SOD), catalase as well as the lipid peroxidative products in the striatum, midbrain and hypothalamus were determined. Our data showed that catecholamines decreased persistently, catalase and Mn-SOD decreased concomitantly, Cu, Zn-SOD, however, remained, unchanged. Lipid peroxidative products increased shortly after injection, then subsided. Our result suggests that lipid peroxidation might be involved in the degenerative process of neurons in Parkinson's disease.

Nonlinear algorithm for identification of a fiducial marker for various cardiac events

We report on a nonlinear algorithm which identifies R-wave peaks on the surface electrocardiogram, consistent reference points on the left ventricular pressure waveform and the initiation of the QRS complex on the epicardial electrogram. The algorithm has been used to evaluate data from horses, ponies, dogs and humans at rest and during exercise. It permits rapid, accurate evaluation of data on a beat-by-beat basis even with noisy signals and varying waveform configurations. The algorithm facilitates the acquisition of detailed information previously difficult or impossible to obtain by more conventional methods of analysis.

In vivo immune selection of a Moloney murine leukemia virus-induced tumor results in the loss of viral- but not tumor-associated antigens

A protocol of in vivo immune selection has been used to isolate a variant of the Moloney murine leukemia virus (MuLV)-induced tumor MBL-2. Characterization of the tumor variant indicated that selection resulted in the isolation of a cell which is incapable of producing infectious virus and no longer capable of synthesizing viral proteins. Although the failure to express viral Ag has rendered the variant tumor cells resistant to lysis by CTL specific for MuLV viral Ag, the variant tumor cells retained their susceptibility to lysis by CTL which appear to be directed against an MuLV-induced tumor-associated Ag. The data indicate that the expression of nonviral tumor-associated Ag by MBL-2 is not dependent upon continued viral gene expression.

In vivo immune selection of a Moloney murine leukemia virus-induced tumor results in the loss of viral- but not tumor-associated antigens

A protocol of in vivo immune selection has been used to isolate a variant of the Moloney murine leukemia virus (MuLV)-induced tumor MBL-2. Characterization of the tumor variant indicated that selection resulted in the isolation of a cell which is incapable of producing infectious virus and no longer capable of synthesizing viral proteins. Although the failure to express viral Ag has rendered the variant tumor cells resistant to lysis by CTL specific for MuLV viral Ag, the variant tumor cells retained their susceptibility to lysis by CTL which appear to be directed against an MuLV-induced tumor-associated Ag. The data indicate that the expression of nonviral tumor-associated Ag by MBL-2 is not dependent upon continued viral gene expression.

Spontaneous improvement after acute ischemic stroke. A pilot study

Recent clinical studies emphasize the importance of early (less than 12 hours after onset) treatment of patients with acute ischemic stroke. Therapies have been proposed as being effective because of early clinical improvement. The frequency and degree of spontaneous improvement in such patients, however, is unknown. We prospectively evaluated the course of 29 patients (19 men, 10 women) aged 33-82 years who were seen less than or equal to 12 hours after the onset of acute ischemic stroke. Seventeen patients were first evaluated less than or equal to 6 hours and the remaining patients at 6-12 hours after onset. All patients were examined using a modified National Institutes of Health Stroke Scale at baseline, 1, 2, 3, and 6 hours. No specific treatment for acute ischemic stroke was given during this time. Improvement (defined as a decrease of greater than or equal to 2 points from baseline score) was noted at 1 hour in seven patients (24%). By 6 hours 15 patients (52%) had improved, 12 (41%) were unchanged, and two (7%) were worse. Our results suggest that spontaneous, often dramatic improvement occurs in patients with acute ischemic stroke and should be taken into consideration in the design of any trial of acute treatment.

[The measurement of radial bone mineral content in children]

The bone mineral contents of radius of 255 boys and 243 girls (7 to 16 year old of the Han nationality, living in Chengdu) were measured with Bone Mineral Analyzer (Type:SPA-I). The standard values of g/cm was made. There was a positive correlation between the value in boys or girls and chronological age, height or weight. The coefficients were respectively 0.83, 0.77, 0.64 in boys and 0.82, 0.82, 0.82 in girls (P less than 0.005). At the age of 13 (in boys or in girls) the value of the g/cm was the highest.

Normal erythrocyte uptake of L-DOPA in Parkinson's, Huntington's, and related diseases

We measured the kinetic constants for the unidirectional influx of L-DOPA into red blood cells of patients with Parkinson's disease (seven patients), Huntington's disease (seven patients), and other extrapyramidal diseases (11 patients), and in five controls. Influx consisted of two components with low affinity and high exchange capacity. In individual subjects, the L-DOPA concentration giving half-maximal influx (Km) varied between 0.04 and 2.19 mM, and the maximum velocity (Vmax) of the saturable transport component was between 20 and 578 mumol/l cell water/h, which is compatible with the neutral amino acids of low affinity for the transport system. The range of Kd (the first-order rate constant for the unsaturable component) was between 0.11 and 0.36 hour-1. There was no gross deficit of the L-DOPA uptake process in patients with Parkinson's disease, Huntington's disease, dystonia, or other extrapyramidal diseases.

Neurotensin interacts with dopaminergic neurons in rat brain

Neurotensin (NT) injected intracerebroventricularly in rat increases dopamine (DA) turnover in the corpus striatum and nucleus accumbens. Significant increases in 3,4-dihydroxyphenylacetic acid (DOPAC) levels occurred within 15 minutes after injection with peak levels at 60 minutes. The effect on NT on DOPAC and homovanillic acid (HVA) accumulation was dose-dependent at 3-100 micrograms. NT, like haloperidol, stimulated 3,4-dihydroxyphenylalanine (DOPA) accumulation in striatal neurons, in the presence of DOPA decarboxylase inhibitor, after injection of gamma-butyrolactone (GBL). NT had a similar stimulatory effect on DOPA levels in the accumbens while haloperidol (0.25 mg.kg-1) had no significant effect in this brain region. NT did not block the inhibitory effect of apomorphine on DOPA accumulation in both the striatum and accumbens, while haloperidol inhibited apomorphine effect in both regions. NT also failed to displace 3H-spiperone from DA receptors and the presence of NT in the binding assay did not alter the ability of DA to displace 3H-spiperone in either brain region. These experiments demonstrate that NT increases DA turnover in both the nigrostriatal and mesolimbic pathways.

Effect of 3',4'-dihydroxy-2-methyl-propriophenone (U-0521) on catechol-O-methyltransferase activity and on DOPA accumulation in rat red blood cells and corpus striatum

The effects of the catechol-O-methyltransferase (COMT) inhibitor 3',4'-dihydroxy-2-methyl-propriophenone (U-0521) were studied in red blood cells (RBC) and corpus striatum in the rat. In vitro U-0521 inhibited RBC COMT activity in a dose-dependent manner with an IC50 of 6 x 10(-6)M. In vivo maximum inhibition (90%) of enzyme activity in RBC was obtained with 250 mg/kg with a peak effect at 5 min and enzyme recovery within 90 min. In U-0521-pretreated rats L-3,4-dihydroxyphenylalanine (L-DOPA) accumulation in RBC and corpus striatum, after injection of L-DOPA, was significantly higher than in nonpretreated rats. The use of COMT inhibitor along with L-DOPA may be of benefit in the treatment of Parkinson's disease.

The effect of chronic L-dopa administration on supersensitive pre- and postsynaptic dopaminergic receptors in rat brain

Chronic administration of haloperidol induced supersensitivity of the pre- and postsynaptic dopaminergic receptors in rat brain. The response of the presynaptic receptors was determined by an enhanced inhibitory effect of apomorphine on dopamine synthesis after gamma-butyrolactone injection. This change in the receptor function was detected both in the nigrostriatal and mesolimbic pathways. Haloperidol also increased the 3H-spiperone binding sites in striatal membranes, indicating supersensitivity of the postsynaptic receptors. Subsequent prolonged treatment with high doses of L-DOPA/carbidopa resulted in a decrease in 3H-spiperone binding sites, but had no effect on the supersensitive presynaptic receptors. It is suggested that tardive dyskinesia may be a state of both pre- and postsynaptic dopamine receptor supersensitivity and that chronic L-DOPA treatment may have a differential effect on these sites.

Catechol-O-methyltransferase inhibition by U-0521 increases striatal utilization of levodopa

The effects of U-0521, a catechol-O-methyltransferase (COMT) inhibitor, were studied on this enzyme activity and on Dopa metabolism in rat striatum. In vivo maximal inhibition (95%) of COMT activity was obtained at 5 min with enzyme recovery to 64% of basal activity at 120 min. When injected in increasing doses U-0521 (200 mg . kg-1) inhibited, at 10 min, COMT activity by 85% with an IC50 = 80 mg . kg-1. In rats pretreated with U-0521 and then with DOPA the accumulation of 3-O-methyldopa-(OMD) in the plasma was essentially blocked while Dopa, dopamine (DA) and 3,4-dihydroxyphenylacetic acid (DOPAC) accumulation in the striatum was significantly higher than in DOPA treated controls. U-0521, a potent COMT inhibitor, enhances the availability and utilization of levodopa in the brain and may thus be helpful in future treatment of parkinsonian patients.