Simultaneous immunofluorescence and autoradiography: a useful technique for investigating neurotransmitter uptake by neurons and glia in primary central nervous system culture

Previous studies on the localization of radiolabelled neurotransmitters in cultured cells of neural origin have relied on the comparison of cell morphology, as determined by immunocytochemistry, with the patterns of labelling on autoradiograms. We present here a method combining simultaneously autoradiography, following the uptake of tritium-labelled amino acid transmitters, with indirect immunofluorescence using antibodies against both surface and intracellular antigens. Using a fixative containing only a low concentration of glutaraldehyde (4% paraformaldehyde, 0.1% glutaraldehyde), a similar retention of gamma-[3H]aminobutyric acid (GABA) and D-[3H]aspartate was achieved as with the higher concentrations commonly used, with the advantage that the autofluorescence associated with glutaraldehyde fixed tissue was eliminated, and the immunoreactivity of the antigens to be localized was not destroyed. Using this method GABA and D-aspartate accumulating cells, in dissociated mouse central nervous system (CNS) cultures, could be reliably identified as oligodendrocytes, and some multiprocessed astrocytes, by anti-galactocerebroside (GC) and anti-glial fibrillary acidic protein (GFAP) immunofluorescence respectively. GABA-accumulating neuron-specific enolase (NSE) positive neurons could be clearly identified but no D-aspartate accumulating neurons were found. This technique should have a wide application in the investigation of whether selective transport mechanisms coexist with antigens characteristic of a certain cell type or sub-type.

High-affinity uptake of gamma-[3H]aminobutyric acid by isolated mouse oligodendrocytes in culture

Oligodendrocytes were isolated from mixed glial cultures of neonatal mouse forebrain and further grown in serum-free hormone supplemented culture medium. Cell populations were identified by indirect immunofluorescence using a range of specific antibodies, revealing a predominantly immature population of oligodendrocytes, the majority expressing the myelin glycolipids galactocerebroside and sulfatide on their plasma membrane. Astroglial contamination was found to be minimal. Simultaneous autoradiography and immunofluorescence demonstrated the presence of a transport system for the major inhibitory neurotransmitter GABA in the oligodendrocytes. The transport system was found to be energy, sodium and temperature dependent. Kinetic analysis revealed a high affinity system, with a Km of 6.27 microM and Vmax of 0.714 nmol/min/mg protein, which is comparable to that found previously for CNS neurons and astrocytes.

Biodegradable resurfacing of the hip in dogs

Arthroplasties of the hips in dogs using a biodegradable poly-L-lactide cup to protect the regenerating cartilage following removal of normal articular cartilage and the drilling of multiple full thickness defects into subchondral bone were performed to determine whether or not the repair response could be improved. The poly-L-lactide cup degraded in approximately 60 days. The regenerating cartilage was much better in the experimental than the control dogs initially, but ultimately failed, perhaps due to inadequate duration of protection of the immature cartilage by the arthroplasty material.

Selective uptake of neuroactive amino acids by both oligodendrocytes and astrocytes in primary dissociated culture: a possible role for oligodendrocytes in neurotransmitter metabolism

CNS glia may be involved in the modulation of neuronal excitability through their capacity to accumulate and metabolize neuroactive amino acids. To investigate the possible role of oligodendrocytes in amino acid neurotransmitter metabolism, we have used light microscopic autoradiography, following the uptake of 3H-labelled amino acids by dissociated cultures of neonatal mouse brain, characterized immunocytochemically using cell-type specific markers. Oligodendrocytes, recognized by their characteristic galactocerebroside membrane staining, rapidly accumulated [3H] gamma-aminobutyric acid (GABA), becoming intensely labelled over cell body and processes after short incubations. In contrast, oligodendrocytes became only lightly labelled with [3H]L-glutamate and aspartate, which preferentially labelled astrocytes. [3H]D-aspartate, a non-metabolized analogue of L-glutamate, was avidly accumulated by oligodendrocytes, labelling cell bodies and processes after short incubations, to a similar extent as GABA. Thus, oligodendrocytes possess a transport mechanism for these excitatory amino acids, but rapidly metabolize them and release the metabolites. Not only the GC-positive cells but also the GC-negative undifferentiated oligodendrocyte precursors accumulated both GABA and D-aspartate, suggesting that this may be a function expressed early in the differentiation of oligodendrocytes. Net uptake of [3H] beta-alanine and [3H]glycine by oligodendrocytes was not observed under any conditions tested. A small number of oligodendrocytes were labelled with [3H]taurine after longer incubations. The uptake of certain neuroactive amino acids is thus a property shared by astrocytes and oligodendrocytes, the latter acting in a protective fashion around neuronal perikarya and axons.

Health promotion for educators: impact on absenteeism

The impact of a comprehensive worksite health promotion program on employee absenteeism in a large metropolitan school district was evaluated. Participants in the program (n = 3,846) did not differ from nonparticipants (n = 8,290) in age or sex distributions. Program participants improved their physical fitness, body composition, coronary risk factors, and overall feeling of well-being. Absenteeism was determined for the study year and for the previous year from records in the district personnel office. Absenteeism differences were evaluated by analysis of covariance by using age, sex, ethnic group, and the previous year's absenteeism as covariates. Participants who completed the health promotion program had an average of 1.25 days less absenteeism (P less than 0.0001) during the study year than nonparticipants. Regression analyses indicated that improvement in physical fitness was associated with less absenteeism. The results suggest that a reduction in absenteeism due to the health promotion program was possibly associated with an improvement in physical fitness.

Prednimustine in refractory non-Hodgkin's lymphoma: a phase II study of the Northern California Oncology Group

Fifty-six patients with advanced non-Hodgkin's lymphoma (NHL) were entered into a phase II study of prednimustine, an ester of chlorambucil and prednisolone. All patients were refractory to extensive prior combination chemotherapy. Therapy with prednimustine, 100 mg/m2/day orally, was given for three consecutive days every 2 weeks. The overall response rate in 43 evaluable patients was 30% (13/43), with 9% (4/43) achieving complete response (CR) and 21% (9/43) achieving partial response (PR). In the favorable histology subgroup (23 patients), the response rate was 39% (9/23), with 4% (1/23) achieving CR and 35% (8/23) achieving PR. In the unfavorable histology subgroup (20 patients), responses were seen in 20% (4/20) with 15% (3/20) achieving CR, all in heavily pretreated diffuse histiocytic lymphoma. Toxicity of this regimen was mild, with leukopenia below 3,000/mm3 in 22% and thrombocytopenia below 90,000/mm3 in 16% of patients. A positive correlation was observed between response and hematologic toxicity, indicating the potential for a dose-escalation schedule in future trials. These data confirm activity of prednimustine in NHL refractory to standard treatment. In view of its relatively mild toxicity, we conclude that prednimustine is an appropriate agent to test in combination chemotherapy regimens in this group of lymphomas.

Long-term survival following relapse after 5-FU but not CMF adjuvant breast cancer therapy

Beginning in 1974, patients with greater than or equal to 4 nodes positive following mastectomy were randomized to receive either 5-FU i.v. weekly or CMF i.v. every 2 weeks, both given for 12 months. Median follow-up now exceeds 112 months with nine year results below: (table; see text) Early results based on relapse-free survival favored CMF, but more patients currently are alive on the 5-FU arm. As the survival curves cross at 40 months, the 20% survival advantage for 5-FU did not achieve statistical significance. For 34% of patients failing adjuvant 5-FU, use of combination chemotherapy after relapse (commonly with CMFVP or CMF) resulted in long term survival. In contrast, long-term survival for patients failing adjuvant CMF was unusual. Relapse was detected while under weekly observation in a greater proportion of patients on 5-FU (36%) compared to CMF (6%) adjuvant treatment (p less than 0.05), potentially influencing tumor burden at recurrence. Hormonal therapy or radiation therapy as initial therapy after relapse was ineffective, with no long term survivors resulting on either arm. Weight increase on adjuvant chemotherapy was commonly seen, with weight increase greater than 10 kg associated with a poor prognosis. We conclude that initial improvement in relapse-free survival may not predict long term survival in adjuvant breast cancer trials since both the specific adjuvant therapy given pre-relapse as well as the type of salvage therapy given post-relapse may influence ultimate patient outcome.

Measurement of anti-cardiolipin antibodies by an enzyme-linked immunosorbent assay (ELISA): standardization and quantitation of results

We describe the development of a simple and highly sensitive double antibody sandwich enzyme-linked immunosorbent assay (ELISA) for measuring IgG and IgM anticardiolipin antibodies (ACA). Microtitre plates were coated with cardiolipin at a concentration of 45 micrograms/ml by evaporation under nitrogen. Non-specific binding of diluted sera was eliminated by blocking of plates with 10% fetal calf serum in phosphate buffered saline (PBS/FCS) for 2 h. Then sera (100 microliters) at a dilution of 1:100 were incubated in the wells for 1 h. Affinity purified goat anti-human IgG or IgM (100 microliters) at a concentration of 1 microgram/ml was subsequently added and allowed to incubate for 1 h; detection of ACA was achieved using an alkaline phosphatase conjugated rabbit anti-goat IgG reagent by reading the colorimetric yield at 405 nm after incubation with substrate. Reference serum pools were established to study reproducibility of the assay throughout its sensitivity range, and Standard curves were established. The quantitative normal range was 0-9.0 Anticardiolipin ELISA Units (AEU) for IgG and 0-8.0 (AEU) for IgM-ACA. A strong correlation was found between the ELISA and radioimmunoassay methods for measuring ACA of both IgG and IgM classes. Results from 65 patients with systemic lupus erythematosus (SLE) and 45 patients with seropositive rheumatoid arthritis are also reported. The advantages of the ELISA method for quantitative determination of ACA levels, should make it a useful and reliable method for clinical and experimental monitoring of patients with SLE and associated autoimmune disorders.

Release of arachidonate from membrane phospholipids in cultured neonatal rat myocardial cells during adenosine triphosphate depletion. Correlation with the progression of cell injury

The present study utilized a cultured myocardial cell model to evaluate the relationship between the release of arachidonate from membrane phospholipids, and the progression of cell injury during ATP depletion. High-energy phosphate depletion was induced by incubating cultured neonatal rat myocardial cells with various combinations of metabolic inhibitors (deoxyglucose, oligomycin, cyanide, and iodoacetate). Phospholipid degradation was assessed by the release of radiolabeled arachidonate from membrane phospholipids. In this model, the current study demonstrates that (a) cultured myocardial cells display a time-dependent progression of cell injury during ATP depletion; (b) the morphologic patterns of mild and severe cell injury in the cultured cells are similar to those found in intact ischemic canine myocardial models; (c) cultured myocardial cells release arachidonate from membrane phospholipids during ATP depletion; and (d) using two separate combinations of metabolic inhibitors, there is a correlation between the release of arachidonate, the development of severe cellular and sarcolemmal damage, the release of creatine kinase into the extracellular medium, and the loss of the ability of the myocardial cells to regenerate ATP when the metabolic inhibitors are removed. Thus, the present results suggest that during ATP depletion, in cultured neonatal rat myocardial cells, the release of arachidonate from myocardial membrane phospholipids is linked to the development of membrane defects and the associated loss of cell viability.

Homonataloin in Aloe species

Homonataloin levels in exudates from cut leaves of a number of ALOE species from the Kew collection have been measured by absorption at 295 nm following separation by reversed phase HPLC. The level was found to be highest in the leaves just below the apex of the plant and to decrease in the older leaves. A range of concentrations was observed in the very variable species A. NYERIENSIS Christian but no taxonomically significant discontinuities were apparent. Other ALOE species containing homonataloin have been examined and levels from 14 per cent to 47 per cent of the exudate dry weight according to species were found.

Uptake of [3H]GABA by oligodendrocytes in dissociated brain cell culture: a combined autoradiographic and immunocytochemical study

Uptake of [3H]GABA by dissociated mixed cell cultures of fetal mouse brain was studied using light microscopic autoradiography. Major cell types in the cultures were identified and quantified by immunocytochemical localization of reliable cell type-specific antigenic markers. In 12 days in vitro (DIV) cultures [3H]GABA uptake was predominantly into neurons and oligodendrocytes, whilst at 28 DIV the only surface cells labeled were oligodendrocytes. This was confirmed by complement-dependent antibody-mediated cytotoxicity against galactocerebroside-positive oligodendrocytes. There was a moderate labeling of almost all flat cells, the majority of which were glial fibrillary acidic protein (GFAP)-positive astrocytes. Heavily labeled astrocytes were only occasionally observed. Oligodendrocytes accumulated [3H]GABA more rapidly than astrocytes but slower than neurons. Oligodendroglial labeling was predominantly over the cell body, whereas neuronal labeling was more uniformly distributed over cell body and processes. The uptake was inhibited by diaminobutyric acid (DABA) and nipecotic acid, but not by beta-alanine, and thus had similar characteristics to neuronal rather than astroglial uptake. Oligodendrocytes did not accumulate [3H]beta-alanine, which labeled only astrocytes. Oligodendroglial [3H]GABA uptake was Na+-dependent and sensitive to ouabain, but was only slightly enhanced by aminooxyacetic acid (AOAA), whereas astroglial uptake was not sensitive to ouabain but was markedly enhanced by AOAA. The results indicate that oligodendrocytes, in addition to astrocytes, may also be involved in the modification of neuronal function by the uptake and inactivation of neuroactive substances.

Chemotherapy of small-cell carcinoma of lung: a randomized comparison of alternating and sequential combination chemotherapy programs

One hundred forty-seven eligible patients with small-cell carcinoma of the lung (SCCL) have been randomized to receive alternating (A) or sequential (S) combination chemotherapy. Initial treatment was with three cycles of VAM (A) or two cycles of POCC (S). VAM consists of VP16-213 200 mg/m2 intravenously (IV) day 1, Adriamycin (Adria Laboratories, Columbus, Ohio) 50 mg/m2 IV day 1, and methotrexate 30 mg/m2 IV day 1 repeated at 21-day intervals. POCC consists of cyclophosphamide 600 mg/m2 IV days 1 and 8, vincristine 1.5 mg/m2 (maximum, 2 mg) IV days 1 and 8, CCNU 60 mg/m2 po day 1, and procarbazine 100 mg/m2 po days 2 through 15. After initial treatment, all patients received whole brain radiation therapy (3,000 rad/10 fractions/2 wk). Patients with limited disease in addition received irradiation encompassing the tumor, hilar, mediastinal, and supraclavicular regions (5,000 rad/25 fractions/5 wk). After radiation, patients on arm A received POCC alternating with VAM; patients on arm S received POCC until progression when they were to be treated with VAM. The alternating arm was superior with respect to rate of complete remission (CR), median disease-free survival (MDFS), and median survival (MS). The advantage of alternating therapy was not as clearly demonstrated in the limited disease groups when interposition of involved field radiation delayed the initiation of the alternating schedule. In limited disease alone, comparing arm A with arm S, no statistically significant differences were noted. The CR rate was 42% v 54%, MDFS was 14 v 10 months, and MS was 16 v 10 months. In extensive disease, the CR rate was 44% v 20% (P = .03), MDFS was 6 v 4 months (P = .003), and MS was 10 v 7 months (P = .001). Improved treatment outcome in SCCL is achieved when combination chemotherapy regimens of similar effectiveness are administered in an alternating rather than sequential schedule.

Phase II study of sequential methotrexate and 5-FU plus mitomycin and leucovorin in patients with disseminated large bowel cancer: a Northern California Oncology Group study

Sequential methotrexate (MTX) and 5-FU plus leucovorin and mitomycin (MMC) was given to 52 patients with disseminated, measurable colorectal cancer. Complete and partial responses were seen in 19 of 49 (39%) evaluable patients. Nine additional patients achieved a minimal response. Median overall survival was 8.8 months, while that for patients objectively responding was 13.6 months. This study utilized a MTX exposure period of 12 hours prior to 5-FU. In comparison to other trials utilizing sequential MTX and 5-FU, the addition of MMC to the regimen may improve the response rate but increases the incidence of adverse effects, particularly myelosuppression and renal toxicity. This phase II trial suggests that sequential MTX and 5-FU plus leucovorin and MMC is an active combination therapy and warrants further comparative trial in patients with large bowel cancer.

Health promotion for educators: impact on health behaviors, satisfaction, and general well-being

A random sample of 117 teachers in three treatment schools and one control school participated in a health survey at the beginning and end of the spring semester. Teachers in the treatment schools participated in a 10-week health promotion program which emphasized exercise, stress management, and nutrition. Comparison of pre- and post-survey data indicated that teachers in the treatment schools increased their participation in vigorous exercise, improved their physical fitness, lost weight, lowered their blood pressure, reported a higher level of general well-being, and were better able to handle job stress.

The surgical treatment of blunt and penetrating injuries of the popliteal artery

Thirty-six patients sustaining blunt and penetrating injuries to the popliteal artery underwent vascular reconstruction with an average ischemic interval of eight and one-half hours (range: four to 14 hours). There were 16 associated venous injuries, 15 nerve injuries, and 20 fractures with or without knee dislocations. Arterial repair was performed by saphenous vein interposition graft in 23 patients and by end-to-end anastomosis in 16 patients (three patients had more than one operation). Eight of the venous injuries were reconstructed and the remaining eight veins were ligated. Fasciotomy was performed in 22 patients. Skeletal stabilization by external support was necessary in 12 instances and by internal fixation in eight patients. Five patients required amputation after vascular reconstruction failed. The presence of an ischemic interval greater than ten hours, associated fractures, and/or knee dislocation carried a serious prognosis for limb survival.

5-Fluorouracil + Oncovin + Adriamycin + mitomycin C (FOAM): an effective program for breast cancer, even for disease refractory to previous chemotherapy. A Northern California Oncology Group (NCOG) Study

One hundred and thirty-one patients (118 evaluable) with disseminated breast cancer were treated with a combination of 5-fluorouracil + Oncovin + Adriamycin + mitomycin C (FOAM). The objective response rate for 82 evaluable patients whose disease was refractory to previous CMF or L-PAM chemotherapy was 35%; that for 36 evaluable patients who had not previously received chemotherapy, 56%. The hematologic toxicity of this therapy was generally mild and acceptable. It is believed that FOAM is an effective therapy for patients whose tumors are resistant to CMF.

Effects of intake of L-ascorbic acid on the incidence of dermal neoplasms induced in mice by ultraviolet light

We have carried out a study of large malignant skin tumors (squamous cell carcinomas) and other lesions in hairless mice (groups of 38-45) intermittently exposed to ultraviolet light over a period of 15 weeks, beginning when the mice were about 10 weeks old. The several groups were given a standard diet with 0%, 0.3%, 5%, and 10% added L-ascorbic acid (vitamin C) throughout the study. No lesions developed in unirradiated control groups. The lesions were counted every 14 days for 4 months, beginning 4 weeks before the end of the period of irradiation. The observed incidence of lesions of several sizes during successive time periods was analyzed by the statistical method recommended by a committee of the International Agency for Research on Cancer. A pronounced effect of vitamin C in decreasing the incidence and delaying the onset of the malignant lesions was observed with high statistical significance.

Phospholipid synthesis in S. cerevisiae strain GL7 grown without unsaturated fatty acid supplements

In the absence of exogenous unsaturated fatty acids (UFA), Saccharomyces cerevisiae strain GL7 synthesizes low levels of UFA and large amounts of decanoic, dodecanoic and tetradecanoic fatty acids. Supplementation with hemin leads to slightly higher levels of UFA, but synthesis of the medium-chain saturated fatty acids (SFA) continues. Under these conditions of limited UFA availability, strain GL7 incorporates most of its UFA into phosphatidylethanolamine (PE), whereas phosphatidylcholine (PC) and phosphatidylserine + phosphatidylinositol (PS+PI) are enriched with the medium-chain SFA. The association of specific fatty acids with the various phospholipids is not accompanied by changes in the proportions of newly synthesized phospholipids, demonstrating that the fatty acid composition of PE can be modulated independently of the other phospholipids. The effect of sterol structure on the fatty acid composition of cells grown with limiting UFA was also examined. Yeast cells grown with either ergosterol or stigmasterol contained less UFA and more medium-chain SFA in their phospholipids than did cholesterol-grown cells, suggesting that the former sterols allow strain GL7 to grow with a lower UFA content.

Proline and glucose transport by renal membranes from dogs with spontaneous idiopathic Fanconi syndrome

The uptake of proline and glucose by renal brush border membrane vesicles isolated from Basenji dogs exhibiting a spontaneous Fanconi syndrome was examined. The magnitude of the 1-min, Na+-gradient uptake of proline (0.02 mM) and glucose (1.0 mM) by vesicles from affected dog kidney was lower than normal. Concentration-dependent 15-sec uptake in vesicles from normal and affected dogs reveals a two-component transport system for proline and glucose. Kinetic analysis shows altered Km and Vmax values for both proline and glucose transport in the affected dogs. The data suggest that, in this model of Fanconi syndrome, the defective renal reabsorption of proline and glucose is associated with an alteration of luminal transport system.

Significance of relapse after adjuvant treatment with combination chemotherapy or 5-fluorouracil alone in high-risk breast cancer. A Western Cancer Study Group Project

Beginning in 1974, patients undergoing mastectomy at high risk for recurrence (greater than or equal to 4 nodes positive; median, 9.4 positive; range, 4 to 28) were randomized after stratification for menopausal status and radiotherapy to receive either 5-fluorouracil (5-FU, 500 mg/sq m i.v. every week) or cyclophosphamide, 400 mg/sq m; methotrexate, 30 mg/sq m; and 5-FU, 500 mg/sq m (CMF; all given i.v. every 2 weeks) in a 12-month program. All 62 patients remain evaluable with median follow-up now exceeding 70 months (range, 60 to 80 months). CMF significantly prevented early disease recurrence (97% relapse free on CMF versus 75% on 5-FU at 12 months; p less than 0.05) and demonstrated survival advantage during the initial 40-month follow-up. This significance was subsequently lost, and the percentages of relapse free and overall survival after 70 months are: (formula, see text) The apparently paradoxical relationship between relapse and survival on the 5-FU arm was related to survival after recurrence. Survival after recurrence was significantly longer on the 5-FU compared to the CMF arm (median of greater than 38 versus 10 months, respectively; p less than 0.01). These results suggest (a) long-term survival in adjuvant trials cannot be accurately predicted by short-term differences in relapse frequency, (b) survival after relapse may be influenced by the antecedent adjuvant therapy received, and (c) disease relapse does not necessarily preclude long-term survival.

Cholestatic jaundice induced by flurazepam hydrochloride

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Penetration of topical clindamycin into comedones

Comedones were removed from patients on topical clindamycin and assayed for that antibiotic by of two methods. Prominent levels were found in eight of ten patients by one bioassay method. Once whole comedones from a patient were found to be positive, other comedones were microdissected to separate the external and internal portions. Prominent levels of clindamycin were found in the inner portion as early as 2 weeks. Further, the antibiotic could always be found in the internal portion when it was present in the external layers. Using the more sensitive of two bioassay methods, the whole comedonal level of clindamycin ranged from 0 to 5 microgram/mg of comedonal material, with an average level of 0.824 microgram/mg. The significance of this is discussed.

Randomized comparison of two combination chemotherapy regimens containing doxorubicin in patients with metastatic breast cancer: a Western Cancer Study Group trial

Ninety-six patients with metastatic breast cancer were entered in a prospectively randomized trial comparing a five-drug doxorubicin (Adriamycin)-containing regimen given in two different schedules. Both regimens included cyclophosphamide, methotrexate, 5-FU, prednisone, and doxorubicin. On one schedule, referred to as "combination" treatment, doxorubicin was given every 21 days and cyclophosphamide was given daily. On the less intensive "fixed-rotation" schedule, doxorubicin was given on alternative cycles every 42 days and cyclophosphamide was given for 21 days of the 42-day cycle. Response frequency and survival were comparable among patients receiving either regimen. Significantly less (P < 0.05) nausea and leukopenia occurred on the fixed-rotation schedule. Therefore, similar therapeutic benefit along with decreased toxicity was obtained by use of combination chemotherapy involving doxorubicin and cyclophosphamide given in the less intensive schedule.

The effect of diamide on amino acid transport by rat renal cortex slices

Diamide directly added to renal cortical slices inhibits the uptake of amino acids. Steady-state kinetic analysis indicates an inhibition of alpha-amino acid influx without effect on efflux. The effect could be reversed by addition of pyruvate to the incubation medium. Although there was a good correlation of the transport effect of diamide with its ability to decrease cellular reduced glutathione concentration, there did not appear to be a necessary connection between them. This was shown by the fact that renal cortical slices stored at 4 degrees C have no alteration in amino acid uptake despite the fact that GSH concentration is as low as that seen with diamide. Diamide was shown to have a direct effect on the uptake of glycine by isolated renal brush border membrane vesicles.

Amino acid content of rat renal cortex and the response to in vitro incubation

The concentration of aspartic acid, threonine, serine, glycine, and alanine is significantly higher in newborn rat renal cortex than in the adult tissue, while phenylalanine and histidine are higher in the adult. When adult cortical slices are placed in bicarbonate buffer at room temperature for 20 min there is a 30-60% decrease in the levels of all amino acids except for lysine, which is slightly higher, and methionine and serine, which do not change. Under the same conditions, newborn cortical slices reveal a similar decrease in only glycine, tyrosine, histidine, and the branched-chain amino acids. On subsequent in vitro incubation of the cortical slices at 37 degrees C for 120 min the concentrations in adult tissue remain at the lower values observed on removal from buffer at room temperature except that glutamic acid, glycine, and lysine levels decrease further and serine increases to the concentration found in fresh tissue. Newborn tissue when incubated at 37 degrees C for 120 min shows amino acid concentrations comparable to unincubated fresh tissue for all except aspartic acid, glutamic acid, serine, and phenylalanine, which reach levels higher than unincubated tissue. The ability of newborn tissue to maintain amino acid pools may play a role in the enhanced transport of some amino acids resulting from preincubation at 37 degrees C (Reynolds et al. Science 184: 68-69, 1974; Reynolds and Segal, Biochim. Biophys. Acta 406: 513-525, 1976).

The potential of grounded theory for health education research: linking theory and practice

This paper offers a critique of present research methods used in the literature drawn upon by health education practitioners, students, and teachers. Weaknesses of deductive methods and of theory which is highly general are noted in terms of their implications for the advancement of health education theory and practice, and in terms of their consistency with traditional principles of practice. The grounded theory method--an inductive approach usually used with participant observation and interview data--is described, and the major arguments for its value are presented. In particular, the empirical generation of middle-range theory can provide a strong link between more general theory and situations faced by practitioners, and definitions of problems are not prematurely closed to reinterpretation from other perspectives. Several recommendations are given for changing the research orientation of health education.

The fanconi syndrome in Basenji dogs: a new model for renal transport defects

The renal defects resulting in a Fanconi syndrome were seen in eight Basenji dogs by measuring renal clearance and in vitro amino acid and sugar uptake and performing histopathologic evaluations. Renal tubular handling of glucose, phosphate, sodium, potassium, uric acid, and amino acids was abnormal, and in vitro uptake of labeled lysine, glycine, and alpha-methyl-D-glucoside by renal cortical slices was impaired. Histopathology was normal except for enlarged nuclei in some renal tubule cells. These Basenji dogs, which may be genetically affected, represent a likely model for idiopathic Fanconi syndrome in humans.

On the development of glycine transport systems by rat renal cortex

The initial uptake of glycine by renal cortical slices from newborn Sprague-Dawley and Long-Evans rats is the same as that observed in adult tissues. Both newborn and adult tissue possess similar high and low affinity glycine transport systems which require an examination of velocity measurements over a wide range of concentration (0.02--50.0 mM) for their discernment. Initial rates of glycine uptake by isolated renal tubule fragments from newborn and adults are similar at a physiological substrate concentration but at high glycine levels there appears to be a decrease in velocity of uptake (V) associated with the high Km system in the young. Whatever preparation of renal cortex is studied, there is a consistent finding that immature tissue is able to accumulate much higher intracellular levels of glycine than the adult, a finding consistent with slower efflux from the cell. An interpretation of the etiology of physiologic aminoaciduria in young animals should take this into account.

Perinatal cytomegalovirus infection: influence of placentally transferred maternal antibody

The kinetics of the response to passively transferred maternal neutralizing antibody were studied for determination of whether this antibody offered protection against primary cytomegalovirus (CMV) infection in the offspring. Antibody response was determined in 17 infants infected in the immediate perinatal period and in 18 appropriate control subjects. Levels of neutralizing antibody in serum obtained at birth and at one month of age were similar in infected and in exposed, uninfected neonates. In addition, the quantity of neutralizing antibody did not influence the time of onset of viruria. Clearly, passive humoral immunity failed to prevent naturally acquired primary CMV infection in a significant number of young infants exposed to virus during and shortly after delivery.

Spontaneous Fanconi syndrome in the dog

Three dogs with spontaneous renal tubular defects similar to idiopathic Fanconi syndrome are characterized. Renal clearance studies revealed a fractional reabsorption of glucose ranging from 31% to 82%. Abnormal glucose thulium values were present in all dogs. A generalized aminoaciduria occurred in two dogs while one had aminoaciduria characteristic of canine cystinuria. Fractional reabsorption of phosphate ranged from 47% to 79%. In vitro uptake of alpha-methyl-D-glucoside was significantly depressed (p less than 0.001). In vitro uptake of amino isobutyric acid was similar to controls. Renal biopsy revealed nonspecific interstitial change in two dogs and normal histology in the other. These animals represent a useful new model for the study of renal tubular transport defects.

Effects of daily rinses using sodium fluoride and organic fluorides on rat caries

The organic fluorides, alexidine dihydrofluoride and amine fluoride, provided greater protection against caries than sodium fluoride when used as a daily mouthrinse in rats. Alexidine dihydrochloride also provided significant caries restriction.

Enhanced carotid sinus baroreflex responses in dogs with chronic A-V block

Effects of carotid sinus pressure on arterial pressure, atrial rate, and ventricular rate were examined in anesthetized normal dogs and in dogs with chronic complete A-V block. Change in arterial pressure per mmHg change in sinus pressure was 0.8 plus or minus 0.2 mmHg for controls but increased (P is less than 0.001) to 1.6 plus or minus 0.1 mmHg in A-V blocked dogs. Arterial pressure was 140-145 mmHg at low sinus pressure in both groups, but at high sinus pressure arterial pressure was significantly lower in A-V blocked dogs (44 plus or minus 4 mmHg) than in controls (92 plus or minus 8 mmHg). These differences were virtually abolished after vagotomy. Heart rate increased in normal dogs as sinus pressure was increased before vagotomy, but decreased after vagotomy. In blocked dogs atrial and ventricular rates decreased at high sinus pressure either before or after vagotomy. The results show that reflex circulatory responses to changes in carotid sinus pressure are enhanced in dogs with A-V block. This enhancement may involve attenuation of buffering influences exerted from other baroreceptors whose afferents are in the vagus nerves.

Regulation of amino acid transport in kidney cortex of newborn rats

After incubation at 37 degrees C the subsequent uptake of alpha-aminoisobutyric acid, cycloleucine, glycine, and L-proline by newborn (as compared to adult) rat kidney cortex slices is enhanced. The effect is abolished by the presence of cycloheximide, actinomycin D, and high concentrations of the above-mentioned amino acids in the medium during the 37 degrees C incubation prior to measurement of uptake. The data suggest that there is an adaptive control mechanism which is expressed on incubation at 37 degrees C and which can regulate amino acid transport in newborn rat kidney cortex.