Fever response in elderly nursing home residents: are the older truly colder?

OBJECTIVE

To test the hypothesis that many nursing home residents with an apparently blunted fever response (maximum temperature less than 101 degrees F) may actually have a significant change in temperature (delta T greater than or equal to 2.4 degrees F) which is not recognized because of a low baseline temperature.

DESIGN

Retrospective chart review for cases of infection that met specific criteria and for chart-recorded baseline and infection temperatures. Chart-recorded baseline temperatures were prospectively compared with re-measurement of morning temperatures.

SETTING

Nursing Home Care Unit of the VAMC West Los Angeles.

PATIENTS

Random review of 40 residents' charts resulted in the detection of 69 infections among 26 residents over a 20-month period. Fifty randomly selected residents prospectively underwent comparison of chart-determined and actual re-measurement of baseline temperatures.

RESULTS

In 50 randomly selected residents, the mean oral baseline temperature of 97.4 +/- 0.2 (degrees F +/- SEM) closely approximated the mean nurse-recorded measures in the charts (97.6 +/- 0.1). Chart review detected 69 infections among 26 residents, with 53 episodes having a temperature recorded during the infection. The mean maximum temperature (Tmax) during an infection was 101.3 +/- 0.3 (degrees F +/- SEM) but 47% (25/53) of the episodes had a "blunted" fever response (Tmax less than 101 degrees F). Of the 25 "blunted" fevers (Tmax less than 101 degrees F), about one-fourth demonstrated an adequate change in temperature from baseline (delta T greater than or equal to 2.4 degrees F) but failed to reach 101 degrees F because of a low baseline. Most infections (89%) had a Tmax greater than 99 degrees F.

CONCLUSION

Establishing a nursing home patient's basal temperature and monitoring for changes in temperature (delta T greater than 2.4 degrees F) and/or lowering the threshold for recognition of fevers (to 99 degrees or 100 degrees F) in nursing home residents with a change in function should assist in early recognition of infections.

Posttranslational cleavage of rat intestinal lactase occurs at the luminal side of the brush border membrane

The intestinal sucrase-isomaltase precursor is cleaved at the brush border membrane by luminal proteases. Whether the lactase precursor also is cleaved by luminal proteases is uncertain. Lactase synthesis and processing was studied in 0- and 15-day-old rats after IP administration of [35S]methionine, and changes in precociously cortisone-induced sucrase-isomaltase were used as an internal control. Mucosal lactase and sucrase-isomaltase were separately immunoprecipitated and analyzed by autoradiography after electrophoresis. In both 0- and 15-day-old rats, mucosal lactase appeared as a 200K lactase precursor band at 30 minutes and as 200K and 225K lactase precursor bands at 60 minutes and was cleaved to form a 130K lactase band 120-240 minutes after labeling; sucrase-isomaltase similarly appeared as 210K and 220K bands at 30-60 minutes and was cleaved to form 140K I and 120K S subunits by 240 minutes in day 15 rats. To determine the role of luminal proteases, intestinal segments were isolated in situ and the luminal contents were flushed 30 minutes after labeling. Unflushed segments were used as controls. Only lactase precursor and sucrase-isomaltase precursor were present 240 minutes after labeling in flushed intestinal segments, but lactase precursor and sucrase-isomaltase precursor were cleaved in unflushed segments. Addition of trypsin or elastase into the lumen of flushed segments resulted in partial cleavage of lactase precursor but not of sucrase-isomaltase precursor. Luminal contents collected from the small intestine of day 15 rats 120 and 240 minutes after labeling showed 35S-labeled 130K and 80K polypeptides in lactase immunoprecipitates. It is concluded that intestinal lactase is synthesized as lactase precursor and transported to brush border membrane and cleaved by luminal proteases, and the amino end polypeptide cleaved from lactase precursor is released into the lumen.

[The in vitro induction of antibody responses of human lymphocytes and its application to hybridoma production]

Sources of immunized lymphocytes constitute one of the main obstacles in the production of human monoclonal antibodies. We tried to get them through in vitro immunization. Cells from excised tonsils or trauma spleens were used for the induction of antibody responses in vitro. Antibodies to different antigens including sheep red blood cells, ovalbumin, tetanus toxoid, and hepatitis B surface antigens were induced in 7-14 days' cultures. Taking tetanus toxoid as antigen, we analysed the various factors required for antibody induction with statistics analysis, which included cell separation method, T cell conditioned medium, antigen dosage, serum content, and concentration of mitogen PWM and LPS. The results showed: (1) The cell separation method influenced the antibody production significantly in comparison with other factors. It signified that immune cells' combination was the most influential factor. (2) Serum also constituted quite important influencing factor especially in the later period of culture. However, it did not make much differences if it attended 10% or so. The antigens and mitogens tended to be used at low concentration. (3) Due to the significant variation among individuals and among different antigens, it is suggested to set up the culture system with some flexibility so as to adapt to the variation in cells and antigens from different sources. The present culture system we use includes nylon wall column separation of cells, suitable range of antigens (three doses instead of one), and either 10% T cell conditioned medium or a mixture of 1 microgram PWM/ ml + 0.1 microgram LPS/ml. The human B lymphocytes stimulated in vitro with tetanus toxoid were used for the construction of human hybridomas.

Thyroxine and cortisone cooperate to modulate postnatal intestinal enzyme differentiation in the rat

Interactions of cortisone and thyroxine (T4) in modulating jejunal sucrase and lactase expression were studied in rats during early postnatal life. Cortisone (50 micrograms/g body wt) precociously induced sucrase activity in days 5-16 rats and enhanced activity thereafter until day 22. T4 (1 microgram/g) plus cortisone evoked greater sucrase expression in day 9 or younger rats. T4 did not induce sucrase expression until day 13. Lactase activity was enhanced in rats younger than day 9 by cortisone, and this effect was abolished when T4 was added. In days 19 and 22 rats, cortisone depressed lactase; with T4, lactase activity was further decreased. T4 alone did not suppress lactase activity until day 19. Quantitation of jejunal enzyme content showed that sucrase catalytic activity was higher in day 22 than 19 or younger rats and lower in rats given T4 than cortisone. In contrast, lactase activity remained constant in all animal groups. In vivo [35S]methionine-labeling studies using day 9 rats showed that cortisone induced de novo synthesis of sucrase and increased 35S incorporation into lactase. Cortisone plus T4 increased 35S incorporation into sucrase further and significantly increased 35S incorporation into lactase. We conclude that 1) cortisone and T4 cooperatively stimulate sucrase expression and reduce lactase activity during early postnatal life and 2) reduction in lactase activity accompanied by increase in lactase synthesis suggests that cortisone and T4 regulate lactase activity at posttranslational level.

Intestinal lactase expression and epithelial cell transit in hormone-treated suckling rats

Cortisone- and/or thyroxine (T4)-induced changes in jejunal lactase activity and epithelial cell migration were studied to determine the relationship of these two events. In suckling rats given a single dose of cortisone on day 6, jejunal lactase activity increased by 37% and cell turnover rate by 95% 3 days later, whereas T4 alone induced no changes. After cortisone plus T4, jejunal lactase activity decreased by 23% while cell turnover rate increased by 176%. Among all animal groups, the patterns of lactase expression along the crypt-villus (C-V) axis were similar, being low at the C-V junction, increasing to a high plateau at the mid- or third quarter villus level, and decreasing slightly at the villus tip. The calculated epithelial cell age at half maximum lactase expression in cortisone-treated and cortisone plus T4-treated rats was 30 and 53% younger than in control rats. Maximum lactase activity in villus cells was approximately 45% higher in cortisone-treated than in control or cortisone plus T4-treated rats. Parallel measurements of sucrase and lactase activities along C-V axis showed elevated lactase activity at higher villus positions than lead sucrase activity, suggesting that cortisone action occurs in villus cells. Thus jejunal lactase expression may be modulated by 1) adjusting villus cell age required for maximum expression, 2) altering the level of lactase activity in villus cells, and 3) changing the turnover rate of lactase containing epithelial cells.

Induction of intestinal differentiation by systemic and not by luminal corticosterone in adrenalectomized rat pups

Potential effects of corticosterone (cort) from maternal milk on intestinal differentiation were studied using adrenalectomized (adx) rat pups fed a formula containing differing amounts of cort. Formula cort concentrations in the range found in milk (0.1-0.5 micrograms/ml) increased the survival of adx rats, but did not induce intestinal differentiation. Formulae containing 1.0-50.0 micrograms/ml cort caused a dose-dependent elevation of serum cort concentrations and jejunal maltase activity and precocious jejunal sucrase induction. Adx rats receiving the formula containing 10 micrograms/ml cort showed serum cort concentrations similar to those in day 15 control rats and jejunal sucrase and maltase activities equivalent to those in day 18-20 control rats, suggesting that the rise in serum cort that occurs during postnatal development suffices to modulate intestinal differentiation. To distinguish between direct local and systemic effects of luminal cort on intestinal differentiation, expression of sucrase was determined in jejunal isografts and in host jejunum from adx rats fed luminal cort. Jejunal isografts and host jejunum expressed similar sucrase activities and showed similar immunofluorescent staining. Moreover, administration of cort by continual ip infusion was more effective than continual intragastric infusion in inducing intestinal sucrase and maltase activities. These data imply that luminal cort is absorbed and transported into the systemic circulation before inducing intestinal epithelial cell differentiation through the systemic route.

Differential effects of thyroxine and cortisone on jejunal sucrase expression in suckling rats

Effects of thyroxine (T4) and cortisone (C) on developmental expression of jejunal immunoreactive sucrase-isomaltase (S-I) and sucrase activity in suckling rats were studied to determine whether these hormones have distinctive actions. Immunoreactive S-I and sucrase activity were absent in infant rats and appeared simultaneously on days 16-18, when cells expressing S-I protein were detected at the villus base. By day 22, the entire jejunal mucosal surface was covered by new cells expressing immunoreactive S-I. Jejunal S-I content surged to adult levels on day 22, whereas the sucrase activity of immunoreactive S-I protein increased continuously until day 32. Administration of 12.5 nmol of T4 or 1.25 mumol of C on day 12 induced precocious expression of jejunal sucrase activity on day 15. T4 also induced sucrase activity in adrenalectomized rats without increasing serum corticosterone concentrations. Both T4 and C appeared to exert their effects in crypt cells, since immunoreactive S-I protein appeared only in villus base cells 24 h after administration. Pulse labeling of [14C]leucine showed that both hormones evoked de novo synthesis of S-I. The S-I induced by C had significantly higher sucrase activity than that induced by T4. We conclude that postnatal development of sucrase activity results from de novo synthesis of S-I with progressively higher catalytic activity until day 32 and these developmental processes are sequentially modulated by thyroid and adrenocortical hormones.

Hormonal regulation of adaptive intestinal growth in artificially reared rat pups

Adaptive growth and precocious expression of sucrase activity occur in the small intestine of artificially reared (AR) rat pups fed a hormone-free diet. The physiological mechanisms underlying adaptive intestinal growth were studied. Day 12 rat pups that received jejunal isografts subcutaneously on day 0 were subjected to artificial feeding and were killed on day 16. Crypt cellularity and DNA labeling index in isografts from AR, but not from mother-fed, rats increased significantly to levels found in in situ host jejunum of AR rats, indicating that humoral regulatory mechanisms are responsible for intestinal cell proliferation in AR pups. Radioimmunoassays of serum corticosterone, thyroxine, insulin, and gastrin and of gastric gastrin contents revealed that only serum corticosterone concentrations were significantly elevated, suggesting that corticosterone plays a critical role for intestinal growth. To examine this possibility directly, day 12 rats were adrenalectomized (ADX) and AR by continuous infusion of diets containing 0, 10, or 50 micrograms/ml corticosterone. Serum corticosterone concentrations paralleled the infused doses of corticosterone. Jejunal DNA labeling index increased in all ADX AR rats at day 13 in a dose-dependent manner. Increased jejunal DNA labeling index was maintained on day 14 in intact AR rats and ADX AR rats fed 10 micrograms/ml corticosterone but not in ADX AR rats receiving 0 or 50 micrograms/ml. We conclude that endogenous corticosterone is one of the systemic factors responsible for the adaptive increase in intestinal growth of AR rats.

Hydrolethalus (Salonen-Herva-Norio) syndrome: further clinicopathological delineation

Two brothers with severe CNS abnormalities, cleft lip/palate, polydactyly, and lung hypoplasia are reported as examples of the hydrolethalus syndrome, an autosomal recessive disorder. Death from cardiopulmonary arrest occurred in patient 1 at age 4 months and in patient 2 at age 17 days. Detailed radiological and neuropathological description is provided on patient 2. We recommend realtime ultrasonography and, when indicated, fetoscopy for antenatal detection of the craniofacial and limb malformations associated with this syndrome.

Enhancement of parathyroid hormone-responsive renal cortical adenylate cyclase activity by a cytosol protein activator from rat reticulocytes

The effects of the cytosol activator protein obtained from rat reticulocytes (RCAP) were investigated in a heterologous membrane system--partially purified cell membranes from dog renal cortex. RCAP enhanced the response of dog renal cortical adenylate cyclase to bovine parathyroid hormone (1-34) [bPTH (1-34)] from two- to three-fold. RCAP also enhanced the response to 5 microM arginine vasopressin, 10 microM glucagon, and 10 microM isoproterenol. Analysis of double-reciprocal plots of substrate concentration and enzyme activity indicated that bPTH (1-34) alone and together with RCAP increased the Vmax of the adenylate cyclase enzyme and did not alter the apparent Km of the enzyme for MgATP. Membranes from dog renal cortex contain 42K and 39K proteins that are ADP-ribosylated by cholera toxin and pertussis toxin, respectively, and appear to be the stimulatory (Ns) and inhibitory (Ni) guanine nucleotide binding proteins described in many other hormone-responsive membrane preparations. Similar to its effects in rat reticulocytes, RCAP inhibited ADP-ribosylation of Ns and enhanced ADP-ribosylation of Ni. The muscarinic agonist, carbachol, inhibited PTH-responsive adenylate cyclase activity in dog renal cortical membranes and this inhibition was reversed by RCAP. These results indicate that RCAP enhances stimulation of adenylate cyclase by a variety of hormones in a heterologous membrane preparation and supports the hypothesis that RCAP's site of action is common to all adenylate cyclase systems. RCAP may facilitate coupling between Ns and the catalytic unit of adenylate cyclase by a pertussis toxin-like effect to inactivate Ni. The dual effects of RCAP upon ADP-ribosylation of Ni and Ns alpha subunits suggest that a binding site for RCAP may exist at a site of homology between Ns alpha and Ni alpha.

Reticulocyte cytosol activator protein: effects on the stimulatory and inhibitory regulatory proteins of adenylate cyclase

Rat reticulocytes contain a cytosol activator protein (RCAP) that augments hormone-sensitive adenylate cyclase activity in the rat reticulocyte and other systems. In a previous publication, using a highly purified preparation of RCAP, we reported that the stimulatory guanine nucleotide-binding protein (Ns) was required for the actions of RCAP. We investigated this possibility by studying the actions of RCAP on cholera toxin-dependent ADP ribosylation of Ns. RCAP decreased cholera toxin-dependent ADP ribosylation of the 42,000-dalton subunit of Ns of reticulocyte [40.2 +/- 3.7 (+/-SEM) to 26.5 +/- 3.8 fmol/mg; n = 10; P less than 0.001], S49 wild-type (33.9 +/- 2.4 to 24.9 +/- 2.8 fmol/mg; n = 9; P less than 0.01), and UNC (25.3 +/- 3.5 vs. 17.6 +/- 3.1; n = 5; P less than 0.02) membranes. In contrast, pertussis toxin-dependent ADP-ribosylation of the inhibitory guanine nucleotide binding protein, Ni in reticulocyte, S49 wild-type lymphoma, and its UNC and cyc- variant membranes were all significantly augmented by RCAP. Moreover, when reticulocyte Ni was functionally ablated by exposure to pertussis toxin, RCAP no longer enhanced isoproterenol-responsive adenylate cyclase activity in reticulocyte membranes. These results suggest that RCAP stimulates adenylate cyclase activity by inhibiting Ni function, thus permitting enhanced Ns coupling to the adenylate cyclase enzyme (C).

Cytosol activator protein from rat reticulocytes requires the stimulatory guanine nucleotide-binding protein for its actions on adenylate cyclase

Rat reticulocytes contain a cytosol activator protein (RCAP) that augments catecholamine-sensitive adenylate cyclase activity in reticulocyte membranes. A highly purified preparation of RCAP, obtained by Sephacryl S-200 chromatography, was used to elucidate further its mechanism of action. The specific activity of the S-200 fraction to augment isoproterenol responsiveness was increased approximately 1,100-fold over the starting material, from 1.2 to 1,300 nmol cAMP formed per mg RCAP. The mol wt of RCAP is approximately 20,000. The effect of RCAP to enhance isoproterenol responsiveness was apparent within 20 sec, virtually abolishing the normal lag time of hormone-activated adenylate cyclase. In addition to its effects on catecholamine-responsive adenylate cyclase, RCAP significantly increased basal [21 +/- 3 (+/- SEM) to 41 +/- 4 pmol/mg protein X 30 min; P less than 0.02], guanyl-5'-yl-imidodiphosphate-associated (3173 +/- 213 to 4339 +/- 365 pmol/mg X 30 min; P less than 0.03), and fluoride-associated (5152 +/- 64 to 5807 +/- 58 pmol/mg X 30 min; P less than 0.05) adenylate cyclase activities. RCAP also altered the characteristics of agonist binding to the beta-adrenergic receptor of reticulocyte membranes, causing an increase in the apparent IC50 for isoproterenol from 0.7 +/- 0.2 to 7.9 +/- 1.6 microM (P less than 0.001). Similar to its effects on reticulocytes, RCAP enhanced isoproterenol- and prostaglandin E2-sensitive adenylate cyclase activity in the wild-type S49 lymphoma cell and shifted the binding isotherm for isoproterenol rightward. In cyc-, the mutant that lacks the stimulatory guanine nucleotide-binding protein (Ns) and in UNC, the mutant in which receptors are uncoupled from N, RCAP was ineffective. Moreover, RCAP decreased agonist affinity for the beta-adrenergic receptor in wild-type S49 cells, but not in cyc- or UNC cells. These observations suggest that RCAP requires a functional Ns unit for its effects on hormone-sensitive adenylate cyclase activity.

Glutamic dehydrogenase from rat heart mitochondria. I. Purification and physical properties including molecular weight determination

Glutamic dehydrogenase extracted with tris buffer from fresh freeze-thawed rat heart mitochondria was purified by ammonium sulphate fractionation, affinity chromatography on GTP agarose, hydroxyapatite chromatography and concentration using a molecular sieve. The final specific activity is 80 units/mg protein. Thin gel SDS electrophoresis of the purified enzyme preparation after reduction with dithiothreitol shows a major band with a molecular weight of 38 000 Daltons. Two minor bands are also present. Sucrose density gradient centrifugation reveals a molecular weight of 230 000 Daltons for unreduced mitochondrial GDH activity. By gel filtration rat heart mitochondrial glutamic dehydrogenase has a major peak at 230 000 Daltons, a minor peak at 300 000 Daltons and some larger molecular weight species. Rat liver mitochondrial glutamic dehydrogenase has a minor peak at 230 000, a major peak at 300 000 and some larger molecular weight species. The rat liver mitochondrial glutamic dehydrogenase predominance at 300 000 is unchanged by incubation, extraction and purification with rat heart mitochondria. The purified GDH is stable frozen at -10 degrees C in tris-HCl buffer with EDTA. It loses activity at 4 degrees C especially when stored in 0.2 M phosphate buffer. It also loses activity when dialyzed for 24 h. This loss of activity is not completely prevented by adding nucleotides to the buffer (AMP or ADP) but is decreased by their presence.

Glutamic dehydrogenase activity in rat heart: demonstration of two forms of enzyme activity

Glutamic dehydrogenase (GDH) activity in rat heart was found to be 2.1 U/g of heart (wet wt). The mitochondrial glutamic dehydrogenase activity accounted for only 18% of the total. This percentage of the total activity in heart mitochondria was not altered by nagarse treatment, acetone extraction, sonication in Triton X-100, and extraction with buffer containing a protease inhibitor. The remainder of the activity was present in the cytosol. Cytosolic GDH activity differed from mitochondrial GDH activity by its pH curve, stability to heat, Arrhenius plot, and the effect of different nucleotides. Acetone extraction of the mitochondria resulted in GDH that was stable to heat and had a shallow temperature activation curve resembling cytosolic GDH. Acetone extraction of cytosolic GDH inactivated it. The cytosolic activity was purified 288-fold and the mitochondrial activity 100-fold. Purified cytosolic and mitochondrial GDH enzymes had different monomeric molecular weights on sucrose density gradient centrifugation. Gel filtration of cytosolic and mitochondrial GDH also showed different monomeric molecular weights. We conclude that rat heart GDH exists in two forms with different physical and kinetic characteristics. The majority of GDH activity in rat heart is cytosolic. The mitochondrial enzyme has a lipid-soluble component that can be removed with acetone without destroying its activity.

Glutamic dehydrogenase from rat heart mitochondria. II. Kinetic characteristics

Glutamic dehydrogenase purified from rat heart mitochondria has been characterized with regard to its substrate kinetics and the influence of nucleotides and potassium phosphate on its kinetic properties. The enzyme had characteristics similar to liver mitochondrial glutamic dehydrogenase. These included several double reciprocal plots which were biphasic, indicating homotropic interaction; inhibition by GTP, which was overcome by ADP and phosphate; and activity with both NAD(H) and NADP(H). There were a number of significant differences however, in the specific kinetic properties of heart mitochondrial glutamic dehydrogenase. The Vmax of reductive amination was four-fold greater with NADH than with NADPH. The maximum rate of oxidative deamination was ten-fold greater with NAD compared to NADP. The differences also included: saturating levels of NADH and NADPH were stimulatory rather than inhibitory; ammonia was stimulatory at millimolar levels; NADP and alpha-ketoglutarate were both inhibitory at saturating levels; and ADP increased reductive amination 30% at lower levels of NADH but inhibited at higher (stimulatory) levels of NADH.

Pulsatile administration of gonadotropin-releasing hormone for induction of ovulation

Chronic pulsatile administration of gonadotropin-releasing hormone (GnRH) was used to induce ovulation in 12 women with various ovulatory disorders. In the first group of eight patients with normal to low baseline levels of gonadotropin, seven responded favorably to the treatment. Follicular maturation was observed in 57% of the treated cycles, and normal ovulatory cycles were induced in 24% of the patients. Two patients became pregnant. The intravenous route of administration was more effective than the subcutaneous one, possibly in response to the GnRH profile after each pulse. (The amplitude of GnRH peaks after an intravenous pulse was four times that seen after a subcutaneous one.) In contrast, follicular maturation and ovulation could not be induced in four women of a second group of patients with normal baseline levels of follicle-stimulating hormone but with high and frequent pulses of luteinizing hormone. The conclusion reached was that pulsatile administration of GnRH can be a new therapeutic tool in the treatment of ovulatory disorders in women who have an insufficient endogenous release of GnRH.

Reticulocyte cytosol activator protein: its actions upon the beta adrenergic receptor and the N-proteins of adenylate cyclase

Rat reticulocytes contain a cytosol activator protein (RCAP) that augments catecholamine-sensitive adenylate cyclase activity in reticulocyte membranes. A partially purified preparation of RCAP was obtained by Sephacryl S-200 chromatography and used to elucidate further its mechanism of action. The specific activity of the S-200 fraction to augment isoproterenol responsiveness is increased approximately 1100-fold over the starting material from 1.2 nmoles to 1300 nmoles cyclic AMP formed per milligram of RCAP. The molecular weight is approximately 20,000. In addition to its effects on catecholamine-responsive adenylate cyclase, RCAP is associated with significant increases in basal (0.9 +/- 0.2 to 1.5 +/- 0.4 nmol/mg; p less than 0.02), guanyl-5'-yl imidodiphosphate [Gpp(NH)p]; (3.9 +/- 0.9 to 4.4. +/- 1.1 nmol/mg; p less than 0.005) and fluoride (4.1 +/- 0.6 to 4.8 +/- 0.6 nmol/mg; p less than 0.005) associated activities. RCAP stimulates isoproterenol responsiveness in wild type S49 cell membranes but is inactive in the mutant line, cyc-. RCAP alters the characteristics of agonist binding to the beta-adrenergic receptor of reticulocyte and wild S49 cell membranes, causing a significant increase in the IC50 for isoproterenol. Direct assessment of Ns and Ni components of the adenylate cyclase complex demonstrates that RCAP inhibits cholera toxin-specific ADP-ribosylation of the 42K subunit of Ns and stimulates pertussis toxin-specific ADP ribosylation of the 39K subunit of Ni.