Climbing fiber afferent modulation during a visually guided, multi-joint arm movement in the monkey

During a visually guided, multi-joint voluntary arm movement Purkinje cell simple and complex spike activity was recorded from the ipsilateral hemisphere and intermediate zone of the cerebellum in the rhesus monkey. The task consisted of moving a manipulandum over a horizontal video screen. Manipulandum (hand position) was represented by a cursor on the screen, the animal required to place the manipulandum within displayed start and target boxes. Purkinje cell complex spike discharge was examined using two paradigms. In the first the animal moved the manipulandum from a start box to a target box. In the second the animal was required to modify an ongoing movement and place the cursor within a repositioned target box. A majority of the cells (44/74) exhibited a statistically significant increase in the probability of complex spike discharge at various times during the movement. The increase was observed when the movement trajectory was redirected (36/44) and/or during the initial portion of the movement (27/44). These results suggest the climbing fiber afferent system is routinely involved in the execution of multi-joint movements especially when the movement is redirected. Possibilities include that climbing fiber afferent input is required when the motor state changes and/or during errors in motor performance.

Climbing fiber afferent modulation during treadmill locomotion in the cat

The relationship of the climbing fiber afferent discharge to the unperturbed and perturbed step cycle was evaluated in the cat. Following a precollicular-premamillary decerebration, cats walked spontaneously on a motorized treadmill. Purkinje cells were recorded extracellularly and simple and complex spikes were discriminated. Right forelimb displacement, biceps and triceps EMG activity, as well as treadmill velocity, were also monitored. In some animals pressure measurements of the contact of the footpad with the treadmill were obtained. Cells were studied during both "normal" and perturbed locomotion. The perturbation consisted of a braking of the treadmill at different phases in the step cycle. Histograms of the simple and complex spike activity, and averages of the right forelimb displacement, biceps, and triceps EMG activity and treadmill velocity were constructed. The complex spike activity of 163 Purkinje cells was averaged through a minimum of 50 sweeps in either normal and/or perturbed locomotion. Statistical analysis revealed that the probability of the climbing fiber afferent discharge in 54% of the cells (36/67) studied during normal locomotion was significantly modulated with the step cycle. For most Purkinje cells the onset of the increase in climbing fiber afferent discharge was coupled to triceps activity and the onset of stance phase. A group of cells exhibited complex spike discharge in association with biceps onset and swing. These observations suggest that complex spike discharge occurs preferentially at the phase transition periods in the step cycle when the trajectory of the forelimb changes from swing to stance or stance to swing. During treadmill braking 51% of the cells exhibited complex spike modulation (70/137). A number of different patterns of climbing fiber afferent modulation occurred. The most common pattern was an increase in complex spike discharge with the resumption of the treadmill movement and locomotion. Analysis of the time of these periods of increased climbing fiber activity suggests that, although in some cells the response is coupled to the treadmill onset, in other cells the modulation occurs at longer latencies. Subsequent analysis aligning the EMG, displacement, and treadmill velocity signals with the times of the climbing fiber afferent discharge suggested some responses were coupled to the reinitiation of the locomotor cycle. The second most common pattern was an increase in climbing fiber afferent discharge at the onset of the perturbation. Also, in some cells, complex spike discharge decreased during the period in which the step cycle was arrested.(ABSTRACT TRUNCATED AT 400 WORDS)

Detection of antibodies to human T-lymphotropic virus type III by using a synthetic peptide of 21 amino acid residues corresponding to a highly antigenic segment of gp41 envelope protein

A peptide of 21 amino acids with the sequence Arg-Ile-Leu-Ala-Val-Glu-Arg-Tyr-Leu-Lys-Asp-Gln-Gln-Leu-Leu-Gly-Ile-Trp- Gly-Cys - Ser encoded by a segment in the env gene of human T-lymphotropic virus type III (HTLV-III), corresponding to amino acids 586-606 of the precursor envelope glycoprotein, has been synthesized by the Merrifield solid-phase method. Combined serological and chemical analyses of this peptide and related peptides have revealed the importance of certain amino acid residues in the antigenic determinant of the relevant peptide. Enzyme immunoassay (EIA) employing this peptide as an antigen adsorbent was shown to reproducibly detect antibodies in sera of patients with HTLV-III infection. This assay provided positive results with all sera that were reactive with gp41 envelope protein of HTLV-III in electrophoretic immunoblot analysis. Thus far, no false-positive sera have been encountered in control populations. Our EIA with this peptide as the coating antigen is shown to have advantages over that with the whole HTLV-III virus as an immunoadsorbent.

Cytochemical and ultrastructural changes in aflatoxin-induced injury to rat liver cells

Young male Sprague-Dawley rats were injected intraperitoneally with a single dose of aflatoxin B1 (AFB1, 3 mg/kg). At 3, 6, 12, and 24 hours and 1, 2, and 5 weeks, the rats were killed and liver samples were taken for examination of sequential ultrastructural changes and localization of acid phosphatase (AcPase), thiamine pyrophosphatase (TPPase) and glucose-6-phosphatase (G6Pase) activity. At 3-6 hrs of AFB1 treatment, the nucleoli became compacted and the network forms of nucleolonema disappeared. Parallel arrays of rough ER encountered in normal liver cells became deranged. Smooth ER increased to form groups of SER anastomosis or vesicles near the golgi area. At 12-24 hours, disruptions of nucleoli, ER systems, and polysomes became more evident. Parallel arrays of ER membranes, forming whorls in the cytoplasm as well as in the cytoplasmic patches (CP), were G6Pase-positive, although the CP were AcPase-negative. The TPPase reaction in bile canaliculi was frequently diminished, but was present in some measure in the Golgi saccules. By 1-2 weeks, most of the injured cells had recovered gradually. The CP disappeared and parallel arrays of RER were observed again in most parenchymal cells. At 5 weeks, the appearance of the nucleoli was normal, as was that of the other organelles. We concluded that the hepatic parenchymal cells had serious lesions at 12 and 24 hours of AFB1 treatment and then recovered nonsynchronously. The response, resistance, and ability to recover from the toxicity of AFB1 varied among the parenchymal cells. The three marker enzymes persisted throughout all regimens of AFB1 treatment.

A cytochemical study of acid phosphatase, thiamine pyrophosphatase and horseradish peroxidase in the Golgi-GERL complex of hepatoma ascites cells

Data from studies of ascitic cells of Chang hepatoma have shown that acid phosphatase (ACPase) can be localized simultaneously within the trans portion of the Golgi apparatus and in tubules of the Golgi-endoplasmic reticulum-lysosome (GERL) system. Reaction products of thiamine pyrophosphatase (TPPase) were also present consistently within trans elements of the Golgi apparatus and within GERL tubules. These new findings indicate that a close physiological association may exist between the Golgi apparatus and GERL, a concept that is consistent with previous observations of fibroblasts. When horseradish peroxidase (PO) is injected intraperitoneally into ascites-bearing rats and the ascitic cells withdrawn at different time intervals, PO could be localized within vesicles and tubules in the GERL region but could not be detected within the Golgi apparatus. Bulk-phase endocytosis requires a long time and a high concentration of PO to occur. The presence of PO within GERL indicates that this organelle may play a role in transporting or processing of certain exogenous proteins.

The treatment of primary childhood acute lymphocytic leukemia with intermediate dose methotrexate

Fifty-four consecutive children with acute lymphocytic leukemia (ALL) were treated from August 1974 until December of 1976 at Rosewell Park Memorial Institute (RPMI) according to a protocol which substituted cranial irradiation with systemic intermediate dose methotrexate (IDM) 500 mg/m2 each 3 weeks for a total of 3 courses immediately following induction. Of 54 patients, 52 went into remission (96%). There were 35 standard risk and 17 increased risk patients according to age and presenting white blood count (WBC). As of September 1979 9 of the 35 standard risk patients had relapsed: (five central nervous system (CNS), three systemic, and one testicular. The overall disease control is comparable to other published methods of therapy involving cranial irradiation but has the added advantage of not exposing these children to the long range side effects currently being observed in children who had previously been treated with prophylactic cranial irradiation.

Cytochemical localization of lectin labeled vesicles in GERL region of hepatoma ascites cells

The fate of lectin labeled internalized plasma membrane in the ascites tumor form of the Chang rat hepatoma growing under in vivo and in vitro conditions was investigated cytochemically. Ascites cells were incubated in Convanavalin A (Con A) and horseradish peroxidase (PO), either with or without prior glutaraldehyde fixation and subsequently treated with 3',3-diaminobenzidine. In cells fixed before Con-A-PO labeling the reaction product was localized as a continuous and even layer upon the external surface of the plasma membrane. If unfixed cells were treated with Con A, coupled with PO at 4 degrees C and reincubated in phosphate buffered saline at 37 degrees C for varying periods of time, the Con-A-PO layer was of irregular thickness. In as little as 15 min of reincubation endocytotic vesicles containing PO positive material were closely associated with GERL components of the Golgi Apparatus. Localization of acid phosphatase (ACPase) within GERL vesicles, similar in size and location to those containing Con-A-PO reaction product, indicates that the Con-A-PO labeled vesicles may be a component of the Golgi apparatus in hepatoma cells.

Intermediate dose methotrexate (IDM) in childhood acute lymphocytic leukemia (ALL)

We employed three courses of intermediate dose Methotrexate (IDM) added onto a standard induction and maintenance program with the concept of both central nervous system (CNS) prophylaxis and simultaneous systemic intensification. Cranial radiation (RT) was not employed as CNS prophylaxis. Fifty of 52 patients (to age 18) achieved complete remission. Time on study now ranges from 22-68 months with a median time of 33 months. We separated the children into standard risk and increased risk. We defined increased risk as a WBC over 30 000/mm3 at presentation and an age of less than two years or greater than 10 years at presentation. There have been 15 relapses on these 50 patients; 11 occurred in increased risk patients (of 22 increased risk patients) and four occurred in standard risk patients (of 28 standard risk patients). There were seven CNS relapses, six systemic relapses, one simultaneous systemic and CNS relapse and one testicular relapse. Toxicity to the IDM was small with the worst problem being mucositis. No leukoencephalopathy occurred. The control of hematological relapse is excellent and the avoidance of potential long-term complications notes is even of greater importance.

High-dose methotrexate in acute lymphocytic leukemia

A pharmacokinetic study of methotrexate (MTX) was performed in 60 patients who received high-dose MTX at 500 mg/m2 infused over 24 hours. MTX levels reached 1.2 X 10(-7) M in the cerebrospinal fluid (CSF) within 10 minutes and remained constant at that level for 24 hours. Forty of these 60 patients were children with acute lymphocytic leukemia. In these 40 patients, simultaneous intrathecal MTX was given along with high-dose MTX. The resultant CSF levels (lumbar area) were higher than those obtained with either high-dose MTX alone or simultaneous intrathecal MTX alone. To date, there have been one systemic and one central nervous system relapse in these 40 children, and the treatment program appears safe to administer.