Adaptation in families with a member requiring mechanical ventilation at home

Current health care trends indicate that ventilator-dependent patients increasingly will be discharged to home after shorter hospitalizations. The purpose of this study was to determine how care givers adapt to having ventilator-dependent adults at home. Twenty families were interviewed in their homes by using an eight-question semistructured interview guide. The Roy model was used as a framework to analyze these data. Two instruments, the Family Coping Scale (F-COPES) and the Family APGAR, were administered to measure family coping and function. Patients, aged 18 to 74 years, required 24-hour (n = 9), 12- to 15-hour (n = 5), or 8- to 12-hour (n = 6) home ventilatory support and had neuromuscular or trauma-related diagnoses. Months receiving ventilation ranged from 2 to 312. Care givers, aged 20 to 74 years, were all relatives. Six care givers reported using support services outside their extended family. F-COPES scores fell within national norms whether the patient required 24-hour or less ventilation. Family APGAR results revealed satisfaction with overall family function although scores decreased over time. Interview data indicated that essential knowledge and skills are taught but additional information is desired. Both positive and negative responses to care giving were identified, with the majority of responses being concerned with role mastery, self-concept, and dependency issues. Positive themes in the interviews reflected confidence in ventilator care, satisfaction with the decision to care for their family member at home, and improved quality of life. Negative themes in the interviews reflected the burden of care giving, the dependence of the patient on the care giver, resentment, and hopelessness.(ABSTRACT TRUNCATED AT 250 WORDS)

Response of glioblastoma cell lines to low dose rate irradiation

Glioblastoma U251 and U87 cells irradiated with single fraction high dose rate radiation (1.1 Gy/min) were relatively insensitive to inactivation of colony forming ability, similar to other glioblastoma cell lines. Initial rates of cell kill with continuous low dose rate irradiation (0.075 Gy/hr to 0.49 Gy/hr) were low, but at times greater than 20 hours and with dose rates of 0.25 Gy/hr or higher, the rate of cell kill increased. Population doubling times for these cell lines were about 24 hours, suggesting that cell cycle redistribution may be responsible for the increased sensitivity. DNA histograms obtained by flow cytometry support this hypothesis, with cells accumulating in the G2 and M phases of the cell cycle. These results suggest that low dose rate irradiation may be effective in treating glioblastomas. Optimization of time intervals between radiation treatments as well as dose rates used for glioblastoma patients may be influenced by these findings, resulting in better integration of continuous low-dose-rate irradiation (radioactive antibodies and implants) and high-dose-rate irradiation (fractionated external beam) into therapeutic programs.

Functional and structural characterization of peptidylamidoglycolate lyase, the enzyme catalyzing the second step in peptide amidation

Carboxy-terminal amidation is a prevalent posttranslational modification necessary for the bioactivity of many neurohormonal peptides. We recently reported that in addition to peptidylglycine alpha-monooxygenase (PAM), a second enzyme, which we now call peptidylamidoglycolate lyase (PGL), functions in the enzymatic formation of amides [Katopodis et al. (1990) Biochemistry 29, 4551]. The monooxygenase first catalyzes formation of the alpha-hydroxyglycine derivative of the glycine-extended precursor, and the lyase subsequently catalyzes breakdown of the PAM product to the amidated peptide and glyoxylate. We report here the first primary sequence data for PGL, which establish that it is part of the putative protein precursor which also contains PAM. We also show that PAM and PGL activities are colocalized in the secretory granular fraction of neurointermediate pituitary as would be expected for enzymes sharing the same precursor. Time course studies of the amidation reaction using purified soluble pituitary PAM and PGL indicate that both enzymes are essential for enzymatic amidation. Finally, PGL has no effect on the substrate or inhibition kinetics of PAM, and purified pituitary PAM has an acidic pH optimum consistent with its known localization in secretory granules.

Differential expression of calbindin-D 28 kDa in rat incisor ameloblasts throughout enamel development

Calbindin-D 28 kDa (CaBP 28 kDa), a vitamin D-dependent calcium-binding protein, has been associated with calcium handling by cells. We have investigated the expression of this protein in the rat incisor enamel organ, an epithelium interposed between a mineralizing matrix and connective tissue rich in blood vessels, by radioimmunoassay (RIA), Western blotting, and quantitative protein A-gold immunocytochemistry with antibodies to rat kidney CaBP 28 kDa. RIA of cytosolic extracts showed that enamel organs contained relatively high concentrations of CaBP 28 kDa (compared to kidney; see review by Christakos S., C. Gabrielides, and W.B. Rhoten 1989 Endocr. Rev., 10:3-25). Immunoblotting of proteins extracted from enamel organ strips revealed an intensely-stained band near 28 kDa throughout amelogenesis following ameloblast differentiation. Immunocytochemically, CaBP 28 kDa was localized exclusively within ameloblasts. The density of labelling increased from the presecretory stage to the secretory stage and fluctuated across the maturation stage in relation to ameloblast modulation. Ruffle-ended ameloblasts consistently showed the most intense immunoreaction. Gold particles were present throughout the cytoplasm and nuclei of ameloblasts but regions rich in rough endoplasmic reticulum or cell webs showed a higher immunolabelling. Some gold particles were also associated with the external face of the rough endoplasmic reticulum. Multivesicular bodies in maturation stage ameloblasts were occasionally immunoreactive. These data suggest that the intracellular concentration of CaBP 28 kDa is regulated throughout amelogenesis reflecting a stage-specific control of calcium homeostasis in ameloblasts.

Circulatory effects of verapamil during normovolemic hemodilution in anesthetized rats

Patients who have undergone perioperative normovolemic hemodilution may require calcium channel blockers for the treatment of myocardial ischemia and/or supraventricular tachyarrhythmias. The purpose of this rodent study was to examine the effect of intravenous verapamil on the hyperdynamic circulatory response to acute normovolemic hemodilution (hematocrit 20%). Anesthetized animals were randomly divided into four groups equal in number: (1) controls (no hemodilution, no drug); (2) hemodilution only; (3) verapamil only; and (4) hemodilution followed by verapamil. Cardiac output was recorded using an electromagnetic flow probe. Pre- and afterload tests were performed, the former consisting of rapid infusion of blood adjusted for hematocrit, the latter consisting of an aortic clamp technique. Animals in group 2 had significantly (P less than 0.05) greater percent increases in cardiac index, stroke volume index, and dP/dt, and greater percent decreases in mean arterial pressure, systemic vascular resistance, and oxygen delivery than did control animals (group 1). Infusion of verapamil after hemodilution (group 4) did not interfere with the compensatory increases in cardiac index and stroke volume index seen in group 2, nor did it reduce the peak stroke volume index in response to preload stress, although it did reduce resting dP/dt, mean arterial pressure and systemic vascular resistance, and peak cardiac index and "left ventricular developed pressure" after preload and afterload stress, respectively. We conclude that reduced ventricular function after verapamil administration does not interfere with the compensatory increase in stroke volume index after normovolemic hemodilution.

Determination of the disulfide bond pairings in bovine transforming growth factor-alpha

A rapid method for determining the three disulfide bond pairings in bovine transforming growth factor-alpha (bTGF-alpha) was developed by digesting bTGF-alpha with thermolysin followed by separation of the generated peptides by reversed-phase HPLC. The disulfide-bonded peptides were identified by amino acid sequencing and fast atom bombardment mass spectrometry. The disulfide bond pairings in bTGF-alpha were determined to be homologous to those in the human and mouse TGF-alpha molecules. A species of low bioactivity isolated from the folding/oxidation mixture of chemically synthesized bTGF-alpha was demonstrated to contain two incorrect disulfide bonds. These results indicate that mispairing of disulfide bonds in bTGF-alpha significantly reduces the activity of this molecule.

Bilateral tension pneumothorax due to a defective anesthesia breathing circuit filter

A 25-year-old healthy patient developed bilateral tension pneumothorax during general endotracheal anesthesia due to a defective anesthesia breathing circuit filter. Prompt diagnosis and treatment of the pneumothorax was facilitated by the use of capnography and pulse oximetry. The manufacturing process of the breathing circuit and filter that made this accident possible has since been corrected by the manufacturer. Anesthesiologists must be alert to the possibility of such accidents with any breathing system using bacterial filters.

cDNA cloning and nucleotide sequence of the wheat streak mosaic virus capsid protein gene

The 3'-terminal region of wheat streak mosaic virus (WSMV) genomic RNA was cloned and a cDNA sequence of 1809 nucleotides upstream of the poly(A) tract was determined. The sequence contains a single open reading frame of 1662 nucleotides and a 3' untranslated region of 147 nucleotides. Translation products from WSMV RNA and WSMV cDNA transcripts were immunoprecipitated by WSMV capsid protein antiserum, indicating that the 3'-terminal region of WSMV RNA encodes the capsid protein. Five potential N-terminal capsid protein protease cleavage sites were identified, which would yield proteins ranging from 31.7K to 46.8K. Alignment of the deduced amino acid sequence of the WSMV capsid protein with those of other potyviruses showed significant, but limited, identity as compared to the alignment of two or more aphid-transmitted potyviruses. Although WSMV has characteristics distinct from potyviruses, because of its particle morphology, translation strategy apparently based on polyprotein processing, the ability to form cytoplasmic cylindrical inclusions and the degree of capsid protein homology with aphid-transmitted potyviruses, it should be considered a member of the potyvirus group.

Altered in vitro adaptive responses of lymphocyte Na+,K(+)-ATPase in patients with manic depressive psychosis

When lymphocytes from healthy subjects are incubated in lithium (8 mM) or ethacrynate (1 microM) they show a time-dependent adaptive response, which consists of a significant increase in the number of Na+,K(+)-ATPase molecules in the lymphocyte membrane. We have studied the lymphocytes from nine euthymic drug-free patients with a history of manic depressive psychosis, and have found that this normal adaptive response was absent. It was also absent from the lymphocytes of euthymic patients taking lithium. We conclude that this altered in vitro adaptive response of lymphocyte Na+,K(+)-ATPase represents an enduring trait marker in manic depressive psychosis.

Effects of propranolol on myocardial performance during acute normovolemic hemodilution

The effects of propranolol and hemodilution on myocardial performance and oxygen delivery were evaluated in 36 anesthetized rats. Oral propranolol treatment consisted of 64 mg/kg/d for 6 weeks prior to the experiments, whereas intravenous (IV) propranolol treatment consisted of 5 micrograms/kg/min for 60 minutes after hemodilution. The hematocrit was reduced to 20% by a hetastarch-for-blood exchange. Animals were divided into six equal groups as follows: (1) no oral drug (water), no hemodilution, no IV drug (saline); (2) oral water, hemodilution, IV saline; (3) oral water, no hemodilution, IV propranolol; (4) oral water, hemodilution, IV propranolol; (5) oral propranolol, no hemodilution, IV saline; and (6) oral propranolol, hemodilution, IV saline. Left ventricular (LV) pressure, maximal dP/dt, ascending aortic blood flow, and response to preload (peak cardiac and stroke volume indices) and afterload (LV-developed pressure) stress were measured. In group 2, hemodilution significantly increased cardiac index, stroke volume index, and dP/dt, and decreased blood pressure, peripheral resistance, and oxygen delivery compared with group 1. Compared with group 2, IV propranolol after hemodilution in group 4 significantly decreased cardiac index, dP/dt, LV-developed pressure, and peak cardiac index, and increased peripheral resistance. Stroke volume index and peak stroke volume index after preload stress remained elevated in group 4, despite the negative inotropic effects of IV propranolol. Oral propranolol in group 6 did not prevent the hemodilution-induced increase in stroke volume index and peak stroke volume index in response to preload stress, although it did decrease cardiac index and dP/dt compared with group 2. Oxygen delivery was reduced in the hemodiluted animals in proportion to the decrease in hemoglobin, regardless of propranolol treatment. It is concluded that reduced myocardial contractility and cardiac performance by nonselective pharmacological beta-adrenoceptor blockade does not interfere with the compensatory increase in stroke volume index after hemodilution.

Pindolol decreases prolactin and growth hormone responses to intravenous L-tryptophan

The effects of pindolol on the prolactin (PRL) and growth hormone (GH) responses to intravenous tryptophan (LTP) were studied in eight healthy male volunteers. Pindolol pretreatment (40 mg over 48 h) markedly attenuated the GH response to LTP and modestly, but significantly, reduced the LTP-induced increase in plasma PRL. The disposition of LTP following infusion was not altered by pindolol. While the data are consistent with 5-HT1A receptor mediation of PRL and GH responses to LTP, the intrinsic sympathomimetic actions of pindolol might also be involved in the attenuation of the endocrine responses to LTP.

Oxidant effects on rat and human lung proteinase inhibitors

This project tested the hypothesis that inhaled oxidants could cause lung damage by inactivating the proteinase inhibitors that normally protect the lung from proteolysis. Rat alpha-1-proteinase inhibitor (alpha 1-PI)2 was purified from blood plasma, and antibodies to this inhibitor were prepared. The activity of alpha 1-PI in lung lavage fluids from rats was measured by elastase inhibition, and the immunological concentration of alpha 1-PI was quantified in an enzyme-linked immunoassay. The ratio of the amount of active alpha 1-PI relative to its immunological concentration was examined as a measure of the inhibitor's functional activity. This ratio and the ratio of the immunological concentration of alpha 1-PI to the total protein concentration were determined in lung lavage fluids from rats exposed to air, 10 parts per million (ppm) nitrogen dioxide, and diesel emissions (3.5 mg/m3 particulates) for 12, 18, and 24 months. Only diesel exposures resulted in a statistically significant reduction in the functional activity of alpha 1-PI of 30 percent (p less than 0.05). Similar studies were performed on rats exposed to nitrogen dioxide (0.5 ppm background with peaks of 1.5 ppm) and ozone (0.06 ppm background with peaks of 0.25 ppm) for 12 and 18 months. No statistically significant effects were observed in the functional activity of alpha 1-PI or its immunological concentration. In other protocols, rats were acutely exposed to 0.8 ppm or 1.2 ppm ozone for two, four, or eight hours, and to 0.5 ppm or 0.8 ppm ozone in conjunction with 8 percent carbon dioxide for two or seven hours. Although these acute exposure conditions did not reduce the functional activity of alpha 1-PI, the immunological concentration of alpha 1-PI and the elastase inhibitory activity, relative to other proteins, were significantly increased in relation to the total amount of ozone inhaled. The functional activity of alpha 1-PI also was measured in the bronchoalveolar lavage fluids of human subjects exposed to nitrogen dioxide (0.05 ppm with 2 ppm peaks, or to 1.5 ppm continuously) for three hours and to ozone (0.4 ppm) for two hours during exercise. These exposures did not result in significant changes in the functional activity of alpha 1-PI or its immunological concentration.(ABSTRACT TRUNCATED AT 400 WORDS)

Alpha-adrenergic agonist drugs, left ventricular function, and emergency from cardiopulmonary bypass

The relationship between preoperative left ventricular (LV) dysfunction and the use of alpha-adrenoceptor agonists during weaning from cardiopulmonary bypass was studied in 102 patients undergoing coronary artery surgery. LV function was evaluated subjectively by examination of the 30 degree right anterior oblique left ventriculogram. Group 1 consisted of 75 patients with normal or mild impairment in LV function, whereas group 2 consisted of 27 patients with moderate-severe LV dysfunction. Cardiovascular parameters were measured at baseline, during hypothermic bypass with the aorta clamped, during normothermic bypass after unclamping, and 1 and 15 minutes after separation from bypass. Thirty-seven patients in group 1 (49%) and 11 patients in group 2 (39%) required some form of inotropic and/or vasopressor support during weaning from bypass. Group 2 required significantly higher cumulative doses of phenylephrine after bypass compared with group 1 (1.69 +/- 0.70 mg, n = 9, v 0.24 +/- 0.04 mg, n = 27, P less than 0.05). Similarly, the dose of norepinephrine infusion in group 2 was 3.3 times that in group 1 (10 +/- 6 micrograms/min, n = 2, v 3 +/- 0.6 micrograms/min, n = 2, P = NS). The higher doses of alpha-adrenoceptor agonists required in patients with moderate-severe LV dysfunction may be due to differences in alpha-adrenoceptor agonist affinity and/or receptor density.

Failure of ceftazidime-amikacin therapy for bacteremia and meningitis due to Klebsiella pneumoniae producing an extended-spectrum beta-lactamase

A multiple trauma patient failed treatment with ceftazidime and amikacin for bacteremia and meningitis due to a Klebsiella pneumoniae strain that produced a novel, plasmid-mediated beta-lactamase. Both pre- and posttreatment isolates were resistant to ceftazidime (MIC, greater than or equal to 64 micrograms/ml) and various penicillins but not to other expanded-spectrum cephalosporins. The beta-lactamase had a pI of 5.25 and was encoded on a conjugal plasmid of approximately 150 kilobases. DNA hybridization studies indicated that the enzyme was a TEM derivative.

Diarrhea associated with tube feeding in mechanically ventilated critically ill patients

This study was undertaken to determine the incidence and duration of diarrhea associated with tube feeding in critically ill adult patients who require mechanical ventilation. Of the 73 subjects studied, 63% had diarrhea associated with tube feeding. This incidence is higher than that reported from other studies of critically ill patients who were not mechanically ventilated. Multiple logistic regression analysis revealed that three variables (higher rates of infusion, greater tube-feeding osmolality, and change of tube-feeding product) were statistically significant predictors of diarrhea incidence. Antibiotic use and serum albumin levels were not predictors. In a stepwise multiple regression analysis, the duration of diarrhea was predicted by frequency of diarrhea, within the first 5 days of tube-feeding onset, tube-feeding product osmolality, and rate of tube-feeding infusion. Serum albumin levels and frequency of diarrhea beyond 6 days of tube-feeding onset did not predict duration of diarrhea. Higher osmolality and infusion rates of tube-feeding products did contribute to prediction of both incidence and duration of diarrhea.

Vegetative/Parasitic transition: control and plasticity in striga development

Striga asiatica (Scrophulariaceae), an obligate parasite of grasses including many of the world's major grain crops, switches from vegetative to parasitic development by the differentiation of the root meristem into the host attachment organ, the haustorium. This change was induced in culture by the exposure to a single, low molecular weight signal molecule, 2,6-dimethoxy-p-benzo-quinone. A concentration of 10(-6) molar quinone and an exposure time of >/=6 hours were required before the developmental process could be completed. With shorter exposure times, haustorial development was prematurely aborted and meristematic elongation was reestablished. The new meristem was capable of developing a second haustorium if reexposed to the signal molecule. These results are discussed in terms of the transition to the parasitic phase and the general control of plant cellular development.

Cardiovascular effects of acute normovolemic hemodilution in rats with disopyramide-induced myocardial depression

The effect of myocardial depression on the circulatory response to acute normovolemic hemodilution (hematocrit 23%) with hetastarch was evaluated in 28 anesthetized Sprague-Dawley rats. Cardiac output was recorded using an electromagnetic flow probe. Mild, moderate, and severe myocardial depression were achieved by infusing disopyramide 50, 75, and 85 mg/kg. This resulted in a dose-dependent decrease in cardiac output (r = -0.73, p less than 0.05) and mean arterial pressure (r = -0.65, p less than 0.05), and an increase in left ventricular end-diastolic pressure (r = 0.77, p less than 0.05) and total peripheral resistance (r = 0.46, p less than 0.05). Following hemodilution, cardiac output and mean arterial pressure were significantly lower and total peripheral resistance significantly higher in animals with myocardial depression compared with saline anemic controls. These differences were dose-dependent for cardiac output (r = -0.83, p less than 0.05), mean arterial pressure (r = -0.68, p less than 0.05), and total peripheral resistance (r = 0.51, p less than 0.05). Although control animals were able to significantly increase their cardiac output and stroke volume after hemodilution compared with baseline, animals with severe myocardial depression were unable to do so. This resulted in marked hypotension after hemodilution in controls compared with severely depressed animals. The results suggest a diminished ability of the pharmacologically depressed heart to tolerate acute normovolemic hemodilution.

Pretreatment with non-depolarizing neuromuscular blocking agents and suxamethonium-induced increases in resting jaw tension in children

We have studied the effect of prior administration of non-depolarizing neuromuscular blocking drugs on suxamethonium-induced increases in masseter muscle tension in 21 children aged 3-10 yr, anaesthetized with nitrous oxide and halothane using supramaximal stimulation of the ulnar nerve and the nerve to masseter. Resting tension and isometric force of contraction were measured in the adductor pollicis and masseter muscles. A sub-paralysing dose of tubocurarine 0.05 mg kg-1, a paralysing dose of atracurium 0.5 mg kg-1 or saline was given, followed 3 min later by suxamethonium 1 mg kg-1. Onset times of suxamethonium and atracurium block were shorter in the masseter than in the adductor pollicis muscle. When preceded by a sub-paralysing dose of tubocurarine, suxamethonium produced an increase in masseter tension (47 (SEM 15) g) similar to that produced by suxamethonium alone (59 (13) g). Prior administration of a paralysing dose of atracurium almost abolished this increase in tension (2.5 (2.5) g) (P less than 0.05 vs saline). The tension increase in adductor pollicis was 0, 3.2 (2.2) and 5.9 (1.1) g in the atracurium, tubocurarine and saline groups, respectively. Tubocurarine and atracurium prevented muscle fasciculations in all patients. It was concluded that increased muscle tone is a normal response to suxamethonium and is greater in the masseter than adductor pollicis. Sub-paralysing doses of non-depolarizing neuromuscular blockers have little effect, in contrast with paralysing doses. This suggests that the effect is mediated via postsynaptic receptors.

Routine use of backscattered electron imaging to visualize cytochemical and autoradiographic reactions in semi-thin plastic sections

The scanning electron microscope (SEM) was used to examine cytochemical and autoradiographic reactions in 2-microns semi-thin sections of tissues conventionally fixed and embedded in various resins. The sections were examined using both the secondary and backscatter modes of the SEM at magnifications within the range attainable with the light microscope. Both modes allowed the imaging of phosphatase reaction product using cerium and lead capture, lectin-gold, and immunogold labeling, with and without silver enhancement, and autoradiography. Backscattered electron imaging (BEI), however, provided images with more contrast and structural details. This approach allows examination of large sections, with more contrast and resolution than the light microscope, and visualization of reactions not visible with this instrument. The improved imaging and the simple and conventional preparation of specimens indicate that BEI can be used routinely to examine tissue organization, cell structure, and the content of the various cell compartments with a resolution approaching that of transmission electron microscopy.

Inflammatory responses and the generation of chemoattractant activity in cowpox virus-infected tissues

Histological examination of the lesions produced on the chick chorioallantois infected with cowpox virus shows extensive haemorrhage but there are few inflammatory cells. However, infection with a deletion mutant, white cowpox virus, results in little haemorrhage but there is massive polymophonuclear cell infiltration. Extracts from tissues infected with the parental, red cowpox virus contained little or no chemoattractant activity detectable in micropore filter assays. However, white cowpox virus-infected tissue extracts, including cellular extracts from infected tissue cultures, had a marked effect in vitro on the migration of both neutrophils and monocytes. The chemoattractant activity induced in ovo by white cowpox virus infection has sedimentation characteristics in sucrose density gradients that are similar to leukotactic factors shown previously to be present in the allantoic fluid of chick embryos infected with paramyxoviruses. Induction of chemoattractant activity did not occur after infection of chick chorioallantois with a recombinant white cowpox virus constructed to express a protein that is responsible for the haemorrhagic character of red cowpox virus. This gene product has been shown previously to have homology with various serine protease inhibitors. The significance of these studies to the immunogenicity and pathogenicity of vaccinia recombinant viruses is discussed.

Indiana dentists acceptance of universal precautions

Dentistry along with other health care disciplines is evaluating infectious control procedures for the protection of patients and staff. The AIDS scare of the early 80s precipitated many concerns leading up to the practice changes reported in this article. The authors have collected survey data over a three-year period, from 1985 to 1988, to document the response of Indiana dentists to new infectious disease control requirements.

Ultrastructural distribution of NADPase within the Golgi apparatus and lysosomes of mammalian cells

Cytochemical studies with over 40 different mammalian cell types have indicated that NADPase activity is associated with the Golgi apparatus and/or lysosomes of all cells. In the majority of cases, NADPase is restricted to saccular elements comprising the medial region of the Golgi stack and an occasional lysosome. There is often weak NADPase activity in other Golgi compartments such as the trans Golgi saccules and/or elements of the trans Golgi network. In some cells, however, strong NADPase activity is found within these latter compartments, either exclusively in trans Golgi saccules or elements of the trans Golgi network, or in combination with medial Golgi saccules and each other including (1) medial Golgi saccules + trans Golgi saccules, (2) medial Golgi saccules + trans Golgi saccules + trans Golgi network, or (3) trans Golgi saccules + trans Golgi network. In some rare cases, no NADPase activity is detectable in either Golgi saccules or elements of the trans Golgi network, but it is observed in an occasional lysosome or throughout the lysosomal system of these cells. It is unclear at present if these variations in the distribution of NADPase across the Golgi apparatus, and between the Golgi apparatus and lysosomal system, are due to differences in targeting mechanisms or to the existence of "bottlenecks" in the natural flow of NADPase along the biosynthetic pathway toward lysosomes. While no clear pattern in the association of strong NADPase activity with lysosomes was apparent relative to the ultrastructural distribution of NADPase activity in Golgi saccules or elements of the trans Golgi network, the results of this investigation suggested that cells having NADPase localized predominantly toward the trans aspect of the Golgi apparatus (in trans Golgi saccules or elements of the trans Golgi network or both) have few NADPase-positive lysosomes. The only exception is hepatocytes which were classified as predominantly trans but had noticeable NADPase activity within medial Golgi saccules and elements of the trans Golgi network as well, and highly reactive lysosomes. Other cells showing highly reactive lysosomes including (1) Kupffer cells of liver and those forming the proximal convoluted tubules of the kidney, both of which also had strong NADPase activity within medial and trans Golgi saccules and elements of the trans Golgi network, (2) Leydig cells of the testis and interstitial cells of the ovary, which also showed strong NADPase activity within medial Golgi saccules, and (3) macrophages from lung, spleen and testis, and Sertoli cells from the testis all of which showed no Golgi associated NADPase activity.(ABSTRACT TRUNCATED AT 400 WORDS)

Cytochemical and biochemical characterization of glycoproteins in forming and maturing enamel of the rat incisor

Biochemical and histochemical studies have shown the presence of various carbohydrates in enamel. Using lectin-gold cytochemistry, we have examined the distribution of glycoconjugates containing N-acetyl-D-galactosamine (GalNAc) and/or N-acetyl-glucosamine (GlcNAc)/N-acetyl-neuraminic acid (NeuNAc) residues in rat incisor ameloblasts and in forming and maturing enamel embedded in Lowicryl K4M, LR Gold, and LR White resins. The enamel proteins that contain these carbohydrate moieties were further characterized by lectin blotting. All three resins allowed, albeit to a variable degree, detection of the binding sites for Helix pomatia agglutinin (HPA) and wheat germ agglutinin (WGA) GalNAc, and GlcNAc/NeuNAc, respectively. In general, Lowicryl K4M permitted more intense reactions with both lectins. Lectin binding was observed over the rough endoplasmic reticulum (weak labeling with WGA), the Golgi apparatus, lysosomes, secretory granules, and the enamel matrix. These compartments were shown by double labeling with WGA and anti-amelogenin antibody, and by previous immunocytochemical studies, to contain enamel proteins. Furthermore, WGA binding was more concentrated at the growth sites of enamel. Lectin blotting showed that several proteins in the amelogenin group were glycosylated and contained the sugars GalNAc and GlcNAc/NeuNAc. Fewer proteins were stained by HPA than by WGA, and the staining pattern suggested that the extracellular proteins recognized by these two lectins are processed differently. The HPA-reactive proteins were lost by or during the early maturation stage, whereas many of the WGA-reactive proteins persisted into the mid maturation stage. The heterogeneous staining of certain protein bands observed with WGA suggests that they contain more than one component. Two distinct glycoproteins containing GlcNAc/NeuNAc also appeared during the maturation stage. These results are consistent with the notion that ameloblasts produce an extracellular matrix composed mainly of glycosylated amelogenins which are differently processed throughout amelogenesis.