Search PubMed⌕ Search

Biomedical subjects

J Grimes

Publications and source records attributed to J Grimes.

At least 37 records · Page 2Linked to original sources
PubMed1994

Hydrochloric acid denaturation of colorectal tumour tissue infiltrated with bromodeoxyuridine.

The thymidine analogue, bromodeoxyuridine, is substituted into DNA during DNA synthesis and can be used to identify those cells which have passed through the S-phase of the cell cycle. Incorporated bromodeoxyuridine can be detected using anti-bromodeoxyuridine monoclonal antibodies which bind to the exposed bromodeoxyuridine in single-stranded DNA after a suitable denaturation step. Hydrochloric acid is the most commonly employed denaturation agent in bromodeoxyuridine monoclonal antibody methodologies. This preliminary study was to validate the hydrochloric acid denaturation step for colorectal tumour tissue infiltrated in vivo with bromodeoxyuridine. Standard immunohistochemistry and flow cytometric techniques using Bu20a were employed across a range of hydrochloric acid concentrations. Although high labelling indices were achieved using acid concentrations of 0.10 M HCl, the optimal hydrochloric acid concentration was not the same in all tumours. Sensitivity of DNA to hydrochloric acid denaturation should be carefully considered in bromodeoxyuridine methodologies using the monoclonal antibody Bu20a.

Antibodies, Monoclonal↗
PubMed1994

Three-dimensional computerised analysis of epithelial cell proliferation in the gastrointestinal tract.

This study describes a new technique for the visualisation and quantitation of glandular epithelial cell proliferation in gastrointestinal mucosa using computerised three-dimensional reconstruction. The tissue used in this study was colorectal biopsy tissue infiltrated in vitro with bromodeoxyuridine (BrdU), although the method could be applied to any gastrointestinal site labelled with any specific marker for cell proliferation. The method is as follows. Five-micron-thick serial sections (> 100) were cut from colorectal biopsies infiltrated in vitro with BrdU. After labelling all the sections for BrdU-positive cells using standard immunohistochemistry, colorectal glands were identified which were completely sectioned within the series. Each microscopic image of the sectioned gland was orientated, digitised and stored using a Kontron image analyser. On each of the stored images, the crypt profile, the positive cells and the negative cells were interactively marked and digitally stored. Using three-dimensional (3-D) reconstruction software, the outer surface of the crypt, the total positive and the total negative fractions could be viewed in three dimensions. The total BrdU-positive cell number could be automatically calculated for the complete crypt or, alternatively, compartmental analysis of the labelling pattern within the crypt could be obtained. This represents a powerful technique: it does not require orientation, it can be carried out on complex glandular structures and is not affected by the biases involved in measuring labelling indices from single tissue sections.

Bromodeoxyuridine↗
PubMed1993

Creating a conditional mutation of Wnt-1 by antisense transgenesis provides evidence that Wnt-1 is not essential for spermatogenesis.

We have used mice transgenic for an antisense construct for Wnt-1 to study the role of this gene in post-meiotic sperm development. The human PGK-2 promoter provided levels of Wnt-1 antisense mRNA in testes in 5 transgenic lines greatly in excess of Wnt-1 mRNA concentrations, and Wnt-1 mRNA levels were greatly decreased in the lines, by 98% in three of them. There was a general correlation between copy number of the insert, levels of antisense RNA, and decreases in mRNA. There was little effect of the antisense transgene on fertility or testicular histology suggesting that normal levels of Wnt-1 transcript are not essential for spermatogenesis.

Animals↗
PubMed1993

Women's participation in community health education: an empirical study.

This study identifies reasons for participation in community health education and determines if selected sociodemographic variables correlate with reasons for participation. The subjects were women (N = 400) who had attended hospital-based health education programs in a midwest urban area. An instrument was developed containing 36 items describing the concept "reasons for participation." Factor analysis revealed six interpretable factors: social acceptance, professional/personal advancement, personal insight, personal satisfaction, fulfillment of responsibilities, and self-enrichment. Age, marital status, occupation, number of children, educational attainment, and family income correlated with three of the six factors.

Adult↗
PubMed1992

Respiratory system stability and abnormal carbon dioxide homeostasis.

We have tested the hypothesis that interactions among eight parameters of the respiratory and cardiovascular systems that determine the loop gain (LG) of the respiratory CO2 feedback control system might account for the degree of stability or instability of breathing patterns in healthy sleeping volunteers as well as in familial dysautonomia (FD) and congenital central hypoventilation syndrome (CCHS) patients. The predictability of cycle duration was tested as well. We measured the values of CO2 sensitivity, CO2 delivery capacity in the circulation, circulation delay, mean lung volume for CO2, and mixed venous PCO2 in 8 FD patients, 2 CCHS patients, and 19 healthy controls. The values of these parameters were used in a mathematical model to compute the LG of the respiratory control system during sleep for each epoch of respiration analyzed. The strength of the ventilatory oscillations (R) was quantified using power density spectra of the ventilation time series. All subjects were studied at inspiratory O2 concentrations (FIO2) of 0.21 and 0.15; CCHS patients and controls were also studied at 0.12 FIO2 to examine the effect of steady-state hypoxia on respiratory system stability. In 2 FD patients, LG was elevated at both levels of FIO2 and periodic breathing was observed; the values of R were elevated. Elevated mixed venous PCO2 and reduced CO2 delivery capacity were chiefly responsible for the abnormally high LG observed. In three healthy volunteers, high LG and unstable patterns were associated with high chemosensitivity. The CCHS patients, however, remained stable even at 0.12 FIO2 because LG remained equivalent to zero due to a lack of chemosensitivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Effect of short-term fasting/refeeding on epidermal growth factor content in the gastrointestinal tract of suckling rats.

Epidermal growth factor (EGF) is trophic for varying regions of the developing gastrointestinal tract (GIT) of suckling rats. The presence of large amounts of EGF in milk from various species, combined with low production of EGF by suckling animals, led to speculation that milk is a major source of EGF for suckling rats. We report that short-term fasting (8 hr) of 12-day-old suckling rats resulted in a significant decrease in the levels of immunoreactive EGF (irEGF) in the GIT. Pups refed by lactating mothers for 1 to 4 hr exhibited an increase in irEGF to original levels, whereas pups fed a rat milk substitute by gastric gavage did not have an increase in irEGF content. The irEGF levels in the GIT of pups that were manually fed normal rat milk, or rat milk substitute supplemented with EGF, returned to the prefasted levels. Fasted suckling rats refed 2 ml of rat milk in 2 h exhibited significantly higher level of irEGF in the GIT than did those refed with 0.5 ml in 45 min. Since rat milk irEGF exists in three distinct forms (A, B, and C; C is equal to authentic submandibular gland EGF, the irEGF forms in the GIT were characterized by native polyacrylamide gel electrophoresis. In the stomach luminal contents of the fed suckling rats, only the larger form, Peak B, was observed. Both the luminal content and the mucosa scrapings of all other segments of all groups contained only Form D (comigrating with desarginyl EGF), a metabolic derivative of EGF. All forms were immunoreactive, exhibited receptor binding, and stimulated DNA synthesis in growth-arrested fibroblasts. The rapid changes in EGF within the GIT of suckling rats suggest the EGF can acutely modify some GIT functions of suckling rats.

Animals↗
PubMed1991

Detection of mutations associated with zidovudine resistance in human immunodeficiency virus by use of the polymerase chain reaction.

A sensitive and specific polymerase chain reaction (PCR)-based assay was developed for four mutations in the reverse transcriptase gene of human immunodeficiency virus type 1 that have been associated with zidovudine resistance. These mutations were correlated in 366 specimens with zidovudine chemotherapy and resistance. Mutations at these four codons were detected only after zidovudine therapy. The usual sequence of appearance of mutations was codons 215, 70, 67, and 219, although individual variations occurred. The degree of resistance was proportional to the number of mutations present, although variable susceptibilities with identical patterns of mutations suggested the likelihood that additional mutations contribute to resistance. The existence of both phenotypic and genotypic mixtures was documented as was the occasional selection of subpopulations with passage of virus in vitro. The many complexities of zidovudine resistance render the assay of limited use for application to individual patients; however, it could prove useful for correlating disease or therapy with the emergence of resistance.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Regional differences in gastrointestinal processing and absorption of epidermal growth factor in suckling rats.

Gastrointestinal processing and absorption in vivo of 125I-labeled epidermal growth factor (125I-EGF) was studied in isolated stomach, jejunum, and ileum of 12-day-old suckling rats. Dose dependency and regional differences in the processing and absorption of EGF were determined. At 60 min after administration of 125I-EGF into the isolated gastric lumen, greater than 90% of radioactive material was recovered from gastric wall and lumen in both suckling and weanling rats. On the other hand, a considerable amount of EGF was absorbed (in immunoreactive and receptor active form) from isolated jejunum and ileum of suckling rats. The absorption of EGF from isolated jejunum and ileum increased linearly with the dose of EGF administered up to 1 microgram/rat; absorption of orogastrically administered EGF was also increased linearly with the dose of EGF administered (up to 5 micrograms/rat). Reverse-phase high-performance liquid chromatographic analysis of tissue extracts demonstrated that 125I-EGF is stable in gastric lumen but only partially stable in the jejunal lumen. Carboxy-terminally processed forms of EGF were detected in the luminal flushings of jejunum and ileum and in the wall of the stomach, jejunum, and ileum. 125I-des(48-53)EGF was found in ileal flushings and in the walls of the stomach, jejunum, and ileum, whereas 125I-des(53)EGF and 125I-des(49-53)EGF were detected in jejunal flushings. Receptor binding of 125I-des(53)EGF was significantly greater (by 57%) than that of intact 125I-EGF, but receptor binding of 125I-des(49-53)EGF and 125I-des(48-53)EGF was greatly diminished by 57 and 86%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorption↗
PubMed1991

Modulation of immunoreactive epidermal growth factor levels in the submandibular gland, pancreas, liver, kidney and gastrointestinal tract of suckling rats by cortisone and tri-iodothyronine.

Suckling rats exhibit age-dependent differences in epidermal growth factor (EGF) levels in several organs. The present studies evaluated the effects of two hormones known for their maturative effect on suckling rats, cortisone and tri-iodothyronine (T3), on immunoreactive EGF levels in specific organs. Suckling rats were administered cortisone (5 mg/100 g body weight per day) or T3 (50 micrograms/100 g body weight per day) on days 8, 9, 10 and 11 after birth, and killed on day 12. Submandibular glands, kidneys, pancreas, liver and gastrointestinal tract mucosa and lumen were assayed for immunoreactive EGF by a species-specific radioimmunoassay. Low levels of EGF in the submandibular glands were increased slightly by both T3 and cortisone treatment. Cortisone evoked a tenfold increase in EGF in the pancreas, but had no effect on levels in the kidney or liver. In contrast, T3 evoked a sixfold increase in the EGF level in the kidney, but had no effect on levels in the pancreas or liver. Hormonal administration had no effect on EGF levels in the stomach. Within the intestinal tract, cortisone had no effect on the luminal EGF content of the duodenum, jejunum or ileum, but caused a decrease in the midjejunum. T3 evoked a decrease in the luminal EGF content of the ileum. The effect of cortisone on mucosal EGF content varied between regions; an increase was seen in the duodenum with a decrease in the midjejunum and ileum. T3 administration resulted in a significant decrease in EGF only in the mucosa of the ileum.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Identification and partial characterization of multiple forms of biologically active EGF in rat milk.

Milk from lactating Sprague-Dawley rats was assayed for epidermal growth factor (EGF)-like activities. A homologous radioimmunoassay (RIA) indicated the presence of immunoreactive material that competed in a nonparallel fashion with submandibular gland rat EGF (sm-r-EGF). The activity in the milk was extracted using antibodies to sm-r-EGF covalently linked to acrylamide beads. This activity was characterized by RIA, nondenaturing polyacrylamide gel electrophoresis, enzymatic digestion, radioreceptor assay, and ability to stimulate incorporation of [3H]thymidine into cultured fibroblasts. The presence of three distinct immunoreactive forms of EGF in rat milk were detected that competed with 125I-labeled r-EGF for binding to the EGF receptor and stimulated DNA synthesis in growth-arrested fibroblasts. Two of the forms are converted to the sm-r-EGF species by tryptic digestion as determined by RIA and migration rates in a nondenaturing polyacrylamide gel. The biological activities are stable to heating in 0.1 M acetic acid and also are stable at pH 9.0. Levels of r-EGF equivalents in milk were low at time of birth (6.3 +/- 1.7 ng/ml) and rose to 35.4 +/- 14.6 by days 4 to 6.

Animals↗
PubMed1990

Dietary modification with dairy products for preventing vertebral bone loss in premenopausal women: a three-year prospective study.

The effect of dietary calcium on vertebral bone mass in women is controversial. In a randomized study we have investigated the effect of dietary modification in the form of dairy products on vertebral bone mass in 30- to 42-yr-old premenopausal women over a 3-yr period. Twenty women increased their dietary calcium intake by an average of 610 mg/day (P less than 0.03) for 3 yr, while 17 age- and weight-matched women served as controls. Calcium intake was monitored by 3-day diet histories and 24-h urinary calcium excretion. The consumption of the dairy products did not alter serum calcium or PTH levels or the fasting urinary calcium to creatinine ratio. Twenty-four-hour urinary calcium excretion increased by 28% (P less than 0.03) in the supplemented women. Dairy product intake was accompanied by increased dietary fat intake, but there were no statistically significant changes in serum cholesterol, low density lipoprotein cholesterol, or high density lipoprotein cholesterol levels. The vertebral bone density in the women consuming increased calcium did not change over the 3-yr period (-0.4 +/- 0.9%). In contrast, the vertebral bone density in the control women declined (-2.9 +/- 0.8%; P less than 0.001) and was significantly lower than that in the supplemented group at 30 and 36 months. The study suggests that dietary modification in the form of dairy products retards vertebral bone loss in premenopausal women. Therefore, increased calcium intake in estrogen-replete premenopausal women may prevent age-related bone loss.

Adult↗
PubMed1989

Hemodynamic and oxygen transport effects of pentastarch in burn resuscitation.

If nonprotein colloid plasma expanders could be demonstrated to be safe and efficacious in burn resuscitation, a significant cost benefit would result. This study was a randomized cross-over comparison of 500 ml of 5% albumin and 500 ml of 10% pentastarch, a new hydroxyethyl starch, in acute burn resuscitation. Pentastarch was an effective plasma expander, resulting in increases of preload, cardiac output, oxygen delivery, and oxygen consumption; the hemodynamic effects of pentastarch infusion were equal or superior to those of albumin. Both albumin and pentastarch infusions resulted in increased bleeding and clotting times; these effects were most likely dilutional. Pentastarch is a promising plasma substitute for burn resuscitation; the effects of a 500 ml infusion are equal or superior to those of albumin. Further study is necessary to assess the safety of larger infusion volumes.

Adult↗
PubMed1989

EGF content in the gastrointestinal tract of rats: effect of age and fasting/feeding.

Immunoreactive rat epidermal growth factor (EGF) was measured in the pancreas and in the mucosa and lumen of the stomach, duodenum, jejunum, midjejunum, ileum, and colon of fed or fasted 5- and 12-day-old suckling, and 3- to 4-month-old adult male rats using a homologous radioimmunoassay. The EGF levels in the pancreas in sucklings were lower than in adults and were unaffected by fasting. Both gastrointestinal mucosal and luminal EGF levels were higher in suckling rats than in adults. Fasting caused a significant decrease in gastrointestinal levels of EGF in the suckling rats but resulted in minimal changes in the adults. Our results show that the content of EGF in gastrointestinal tract is dependent on both age and dietary status. Together with the fact that milk contains a large amount of EGF (O. Koldovský and W. Thornburg, J. Pediatr. Gastro. Nutr. 6: 172-196, 1987) and that labeled EGF is absorbed to a considerable extent by the gastrointestinal tract of suckling rats (P.A. Gonella et al., J. Clin. Invest. 80: 22-32, 1987: W. Thornburg et al., Am. J. Physiol. 246: G80-G85, 1984), our present study implicates milk as an important source of EGF in the suckling period.

Age Factors↗
PubMed1989

Breath-by-breath respiratory timing and volume control during periodic breathing.

We examined the control of respiratory pattern during non-rapid-eye-movement sleep-related periodic breathing (PB) in adults, with and without hypoxia. We analyzed 186 cycles of PB from 18 epochs occurring in eight subjects; the mean (+/- SD) cycle duration was 30.8 +/- 8.4 s. Significant oscillations occurred in inspired tidal volume (VT), inspiratory duration (TI), mean inspired flow, inspired minute ventilation, and expiratory duration (TE) (P less than 0.005). For each epoch of PB, moving cross-correlation (MCC) functions were employed to describe the time-dependent intervariable relationships between 1) TI vs. TE, 2) VT vs. TE, and 3) VT vs. breath duration (TT) as synchronization, a strong and consistent intervariable correlation; relative coordination (RC), a weaker interaction characterized by an unstable MCC function oscillating at a subharmonic of the PB frequency; or as independence, with no statistical evidence of interaction. Fourteen epochs showed RC between TI and TE, 11 and 12 of which also showed RC between VT and TE, and VT and TT, respectively. In 4 epochs negative synchronization was exhibited by all three variable pairs. In no case were the oscillations between any pair of variables independent. The modes of coupling between variables were not correlated to O2 saturation, end-tidal CO2 levels, or inspired O2 level. We conclude that during sleep-related PB a nonrandom but weak coupling usually exists between TI and TE, VT and TE, and VT and TT.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1989

Effect of selected anthelmintics on three common helminths in the brown pelican (Pelecanus occidentalis).

The effect of selected anthelmintics (albendazole, fenbendazole, piperazine dihydrochloride and clorsulon) against three major helminths (Contracaecum multipapillatum, Mesostephanus appendiculatoides, and Phagicola longus) were studied in 29 brown pelicans (Pelecanus occidentalis). Albendazole and fenbendazole were highly effective against all three parasites. Clorsulon had moderate effect against M. appendiculatoides and poor effect against C. multipapillatum and P. longus. Piperazine dihydrochloride had no effect against these helminths.

Albendazole↗