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Biomedical subjects

J Heath

Publications and source records attributed to J Heath.

At least 19 recordsLinked to original sources
PubMed1992

Enzymic activity of salivary amylase when bound to the surface of oral streptococci.

The enzymatic activity of salivary amylase bound to the surface of several species of oral streptococci was determined by the production of acid from starch and by the degradation of maltotetraose to glucose in a coupled, spectrophotometric assay. Most strains able to bind amylase exhibited functional enzyme on their surface and produced acid from the products of amylolytic degradation. These strains were unable to utilise starch in the absence of salivary amylase. Two strains failed to produce acid from starch, despite the presence of functional salivary amylase, because they could not utilise maltose. Strains that could not bind salivary amylase failed to produce acid from starch. In no case was all the bound salivary amylase active, and two strains of Streptococcus mitis which bound amylase did not exhibit any enzyme activity on their cell surface. The ability to bind amylase may confer a survival advantage on oral bacteria which inhabit hosts that consume diets containing starch.

Acids↗
PubMed1992

Influence of morbid obesity and non-insulin-dependent diabetes mellitus on high-density lipoprotein composition and subpopulation distribution.

The chemical composition, subpopulation distribution and peak hydrated density of high-density lipoprotein (HDL) were examined in 18 morbidly obese women with either normal glucose tolerance or with non-insulin-dependent diabetes mellitus (NIDDM), and in 15 age-matched lean control subjects. Similar measurements were made in the morbidly obese subjects after gastric bypass surgery for weight loss. In the diabetic group, HDL was relatively protein-enriched and cholesterol- and cholesterol ester-poor compared with the lean controls. The same trend was seen in the nondiabetic group, although the cholesterol ester difference was not significant. In both cases, both electrophoretic and density gradient analysis showed that plasma HDL contained more of the HDL3 and less of the HDL2 subfractions than that for the lean controls. Following surgery in the diabetic group, the protein percentage of HDL decreased, and that of cholesterol ester increased; for the nondiabetic group, the protein decreased and phospholipid increased. In the diabetic group, a shift of the electrophoretic HDL subpopulation distribution toward more HDL2 accompanied these changes. Average hydrated peak density of HDL shifted from the HDL3 to the HDL2 range for the diabetic group following surgery; for the nondiabetic group the peak density also decreased but still remained within the HDL3 range. In all cases, the differences seen were more pronounced among the diabetic patients. These changes in the properties of HDL after gastric bypass surgery may favorably influence the risk for coronary heart disease usually associated with diabetes.

Adult↗
PubMed1992

Baculovirus expression of the nucleoprotein gene of measles virus and utility of the recombinant protein in diagnostic enzyme immunoassays.

A recombinant baculovirus that expresses the nucleoprotein gene of measles virus (Edmonston vaccine strain) under the transcriptional control of the polyhedrin promoter was generated. The expressed protein (B-MVN) comigrated with the authentic viral nucleoprotein as observed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and it was phosphorylated. The B-MVN protein proved to be reactive with monoclonal antibodies in radioimmunoprecipitations, and it was immunogenic, eliciting in mice antisera that recognized the native nucleoprotein. In addition, the B-MVN protein was evaluated as a replacement source of antigen for whole virus in enzyme immunoassays (EIAs) for detection of measles virus-specific immunoglobulin M (IgM) and IgG antibodies. A capture IgM EIA with the B-MVN protein as antigen detected specific IgM antibodies in 18 (72%) acute- and all convalescent-phase specimens from 25 clinical measles cases and exceeded 99% specificity with 120 control specimens. An indirect IgG EIA with the B-MVN protein detected specific IgG antibodies in 129 of 131 (98%) serum specimens with antibodies to measles virus, and results obtained from testing 268 additional serum specimens were better correlated with measles virus-neutralizing antibodies than those obtained with a commercial EIA.

Antibodies, Viral↗
PubMed1992

Early detection of water intoxication.

1. It has been estimated that between 3% and 6% of patients in psychiatric treatment settings are affected by water intoxication. Water intoxication with consequent hyponatremia can result in disturbing clinical conditions. 2. Early detection is an important factor because of the insidious nature and rapid development of this syndrome. 3. A risk analysis for the early detection of this serious condition has been developed. It is easily administered and effective in categorizing a patient's level of risk.

Adult↗
PubMed1990

Sterile water used for humidification in low-flow oxygen therapy: it is necessary?

Currently it is standard practice in many acute care hospitals to use only sterile water in humidifier reservoirs for the delivery of low-flow oxygen therapy. This practice is based primarily on the Centers for Disease Control's 1982 "Guideline for the Prevention of Nosocomial Pneumonia." The present study was designed to investigate and compare the bacterial contamination of tap water and sterile water used to fill clean (nonsterile) disposable oxygen humidifier reservoirs. Disposable oxygen humidification reservoirs were assembled weekly according to standard protocol and regulated to deliver oxygen, 4 to 6 L/min, continuously for 5 consecutive days. Each of 48 reservoirs was filled with either tap water (24) or sterile water (24) and cultured daily. All disposable equipment was discarded after the final culture on the fifth day. An aliquot of water was obtained daily from each reservoir and plated to trypticase soy agar pour plates and to a matched trypticase soy broth. Bacterial growth was observed on trypticase soy agar pour plates from 54 (45.0%) of 120 sterile water reservoir cultures and from 38 (31.7%) of 120 tap water reservoir cultures (p greater than 0.05). Bacterial growth from the matched trypticase soy broth cultures was observed only from two sterile water reservoirs. The microorganisms identified from the sterile water reservoirs included Enterobacter agglomerans and Serratia and Bacillus spp. The use of tap water for low-flow oxygen humidification was determined to be safe at our hospital by the infection control committee. This procedural change contributed approximately $6000 to the cost reduction efforts of the respiratory therapy department.

Centers for Disease Control and Prevention, U.S.↗
PubMed1990

Influence of obesity, impaired glucose tolerance, and NIDDM on LDL structure and composition. Possible link between hyperinsulinemia and atherosclerosis.

The possible causes of the enhanced risk for coronary heart disease (CHD) were examined in morbidly obese women with normoglycemia, impaired glucose tolerance (IGT), and non-insulin-dependent diabetes mellitus (NIDDM) before and after gastric bypass surgery. Compared with age-matched lean women, plasma lipid and apolipoprotein concentrations of the obese women before surgery favored atherogenesis. The risk for CHD may further be exacerbated in the IGT and NIDDM groups by the prevalence of smaller and denser low-density-lipoprotein (LDL) particles. LDL size correlated negatively with plasma insulin levels independent of triglyceride levels, age, or body mass index (BMI). After surgery, BMI, plasma insulin, and triglyceride levels decreased, but LDL size increased, and LDL density decreased. Neither cholesterol nor LDL cholesterol levels were affected after surgery, but high-density-lipoprotein cholesterol was increased in all patients after surgery. Although the mechanisms underlying the changes in the properties of LDL could not be determined from this study, these changes appear to be of benefit in reducing CHD risk in these patients.

Adult↗
PubMed1989

Osteocalcin as an index of osteoblast function during and after ovine pregnancy.

Fetal and neonatal calcium requirements impose heavy demands on maternal bone and mineral homeostasis. The functional response of maternal osteoblasts to this stress is poorly understood. Therefore, plasma osteocalcin (OC) levels were measured by homologous RIA in age-matched nonpregnant, pregnant, and postpartum ewes to evaluate osteoblast function. In pregnant ewes from day 35 of gestation to term, the plasma OC level was suppressed to 8.2 +/- 0.5 micrograms/liter (mean +/- SEM; n = 36) compared with age-matched nonpregnant ewes (18.3 +/- 1.1 micrograms/liter; n = 39; P less than 0.0005). Plasma OC rose to the nonpregnant value by day 20 postpartum and was elevated above this level for the following 40 days (e.g. 44.0 +/- 5.0 micrograms/liter at 48-53 days; P less than 0.0005). The timing of changes in plasma OC levels and weaning did not correlate. The validity of plasma OC measurement as a marker of osteoblast function was assessed by determining the OC plasma production and clearance rates using an [125I]ovine OC infusion method. The OC plasma production rates in matched controls (n = 6), pregnant (n = 9), and 48-53-day postpartum sheep (n = 7) were 1.5 +/- 0.2, 0.5 +/- 0.04 (P less than 0.001 vs. control), and 3.6 +/- 0.6 mg/day (P less than 0.005 vs. pregnant sheep), respectively. In one ewe studied longitudinally, the OC plasma production rate increased by 15 days after parturition and achieved a 10-fold elevation at 49 days postpartum. The OC plasma clearance rate (3.3 +/- 0.3 liters/h) was the same in control, pregnant, and postpartum ewes. It is concluded that 1) changes in plasma OC levels during and after ovine pregnancy reflected changes in OC production, 2) plasma OC measurements are likely to be a useful index of osteoblast function in pregnancy, and 3) osteoblast function appears to be depressed during ovine pregnancy and enhanced markedly in the interval 20-60 days postpartum. The relationship between osteoblast function, as indicated by OC production, and bone formation remains to be clarified.

Aging↗
PubMed1987

Embryonal carcinoma-derived growth factor activates protein kinase C in vivo and in vitro.

We have recently reported that a polypeptide mitogen, the embryonal carcinoma-derived growth factor (ECDGF), induces phosphorylation of the epidermal growth factor (EGF) receptor in intact C3H 10T 1/2 mouse fibroblasts with concomittant loss of high affinity EGF binding sites. This phenomenon appears to be mediated through an activation of protein kinase C. Several groups have described an acidic 80,000 dalton protein substrate of protein kinase C. In this paper, we demonstrate that the addition of ECDGF or the phorbol ester TPA to intact C3H 10T 1/2 cells results in the enhanced phosphorylation of this 80 kd protein in vivo. Furthermore, this response is demonstrable in vitro. Thus the addition of ECDGF, the phorbol ester TPA, protein kinase C or phosphoinositidase C to crude membranes prepared from C3H 10T 1/2 cells resulted in the enhanced phosphorylation of this protein. Data obtained by phosphopeptide mapping of the 80 kd protein show that the ECDGF-induced activation of protein kinase C in our membrane preparations is comparable with that obtained in vivo. The availability of an in vitro system in which this response is preserved should now allow a detailed biochemical analysis of the steps between binding of a mitogen to its receptor and the activation of protein kinase C.

Animals↗
PubMed1987

Airway involvement in ulcerative colitis.

Two patients with ulcerative colitis developed progressive obstructive pulmonary disease. In one, the abnormality was a sclerosing peribronchiolitis confined to small airways, while the other demonstrated a large airway fibrotic obliterative bronchitis. A review of airway involvement in ulcerative colitis and a discussion of the possible similarity to another extraintestinal manifestation of ulcerative colitis, sclerosing cholangitis, are presented.

Adult↗
PubMed1985

Myelin-associated glycoprotein and other proteins in Trembler mice.

The myelin-associated glycoprotein (MAG) and other myelin proteins were quantitated in homogenates of whole sciatic nerve from adult and 20-day-old Trember mice. In the nerves of adult mice, the concentration of MAG was increased from 1.1 ng/micrograms of total protein in the controls to 1.4 ng/micrograms protein in the Tremblers. By contrast, the concentrations of P0 glycoprotein and myelin basic proteins were reduced to 27% and 20% of control levels, respectively. Immunoblots demonstrated that P2 was also greatly reduced in the Trembler nerves. The specific activity of 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP) was 65% of the control level. Immunoblot analysis showed that MAG had a higher than normal apparent Mr in the sciatic nerves of the Trembler mice, but its apparent Mr was normal in the brains of these mutants. In 20-day-old Tremblers, the P0 and myelin basic protein were reduced slightly less to about 40% of the level in the nerves of age-matched controls. CNP and MAG levels were not significantly different from those in controls, and MAG exhibited a shift toward higher apparent Mr similar to that in the adults. The maintenance of high MAG levels despite the severe deficit of myelin, as reflected by the decrease of the major myelin proteins, is consistent with the immunocytochemical localization of MAG in periaxonal Schwann cell membranes, Schmidt-Lantermann incisures, lateral loops, and the outer mesaxon and its absence from compact myelin. The abnormal form of MAG in the peripheral nervous system (PNS) of the Trembler mice may contribute to the pathology in this mutant.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1979

The effects of radiotherapy on immunity in patients with localized carcinoma of the cervix uteri.

To assess the effects of radiotherapy on immune status, a wide range of assessments have been performed on patients with localized carcinoma of the cervix uteri undergoing and initially responding clinically to radical pelvic radiotherapy. Neutrophil function was essentially unchanged by treatment. Absolute neutrophil and lymphocyte counts fell after treatment and remained depressed 3 and 12 months following treatment. The proportions of T and B cells dropped with treatment but recovered to near-presentation levels during the follow-up period even though absolute counts remained depressed. In vitro tests of cellular immunity were depressed by treatment and remained so 3 and 12 months following treatment whereas skin test responses remained normal throughout the assessments. Inhibitory plasma effects were observed in phytohaemagglutinin lymphocyte transformation studies on 4 untreated patients; at follow-up these effects were not evident. A variable response in immune indices has therefore been observed in patients in remission after treatment of localized carcinoma cervix stressing the importance of assessing several aspects of immune function and implying that persistent depression of certain indices does not adversely affect the host tumor response. In two patients relapsing after apparently good initial response all aspects of immunological assessment (except serum immunoglobulin levels and neutrophil function) deteriorated.

Cell Migration Inhibition↗