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Biomedical subjects

J E Bauman

Publications and source records attributed to J E Bauman.

At least 19 recordsLinked to original sources
PubMed2001

Efficacy of the GnRH analogue deslorelin for suppression of oestrous cycles in cats.

The aim of this study was to develop a method for long-term but reversible inhibition of oestrous cycles in female cats by downregulation of GnRH receptors with deslorelin released from a long-acting implant. In a blind study with mature cats (n = 20), a 6 mg deslorelin implant was administered s.c. to ten cats and a placebo implant was administered to ten cats. Occurrence of oestrus and general health were observed daily, and individual faecal samples were collected at 3 day intervals for 14 months and analysed for oestradiol content. All the placebo-treated queens continued to undergo normal oestrous cycles during the study. Oestrus was accompanied by peaks in oestradiol concentrations of > or = 20 ng g-1 faeces. Treatment with deslorelin initially stimulated oestradiol release, which accompanied treatment-induced ovulations. Thereafter, oestradiol concentrations decreased to 1-10 ng g-1 faeces and remained low for extended periods. Observations of small increases in oestradiol concentrations in one cat led to a second treatment with 6 mg deslorelin in five cats on day 155 after first treatment. Faecal oestradiol concentrations remained < 20 ng g-1 faeces in the five single treatment cats for 8.0, 8.5, 11.0 and 14.0 (two cats) months. Cats receiving two implants had the first oestradiol peak > 20 ng g-1 faeces after treatment at 7.5, 11.0 (two cats), 11.5 and 14.0 months. After 14 months, two cats had returned to normal cyclic activity, two had irregular small oestrogen peaks and six showed no cyclic activity. For months 2-5, 6-10 and 11-14, oestrogen values in treated cats were significantly different from control values (P < 0.001, 0.05 and 0.02, respectively). Differences in oestrogen concentration between control cats and cats that were treated twice were significant (P < 0.001) during months 6-10 only. The general health of treated cats was unchanged throughout the study. These results confirm that deslorelin can effectively suppress ovarian activity in domestic cats, but that the duration of suppression varies among individuals.

Animals↗
PubMed1998

Platelet adhesion and aggregation in pulsatile shear flow: effects of red blood cells.

An in vitro test system was developed to examine the effects of red blood cells (RBC) on shear-induced platelet adhesion (SIPAD) and platelet aggregation (SIPAG). Suspensions of human platelets labeled with Mepacrine and suspended in citrated plasma were exposed to single, continuous or repetitive (120-300x) one second shear stress pulses of varying amplitude (15-100 dyn/cm2) in a cone-plate viscometer in the presence or absence of fresh, untreated (intact) RBC or glutaraldehyde (GLA)-fixed, rigid, adenosine diphosphate (ADP)-depleted (GLA)-RBC. SIPAG was expressed as percent loss of single platelets. SIPAD was assessed by measuring the amount of Mepacrine-related fluorescent material remaining on glass disks in the plate of the viscometer after washing with EDTA-saline to remove platelet aggregates. Intact RBC were twice as effective as GLA-RBC in potentiating SIPAG at all shear stress levels. Potentiation of SIPAD by intact RBC was markedly less than that observed with GLA-RBC at stresses below 50 dyn/cm2. These findings are consistent with the concept that while both physical and chemical (ADP) mechanisms are substantially involved in potentiation by RBC of SIPAG, RBC support SIPAD largely by enhancement of platelet transport from the bulk flow to the bounding surfaces. The findings also indicate that it is feasible to assess SIPAD and SIPAG in the same flow system simultaneously. A less complicated version of the method described here should prove useful in the evaluation of patients with platelet functional disorders, and in the evaluation and monitoring of antiplatelet agents.

Blood Platelets↗
PubMed1997

Protection of dogs against canine distemper by vaccination with a canarypox virus recombinant expressing canine distemper virus fusion and hemagglutinin glycoproteins.

OBJECTIVES: To evaluate the safety and efficacy of a live canarypox virus recombinant-canine distemper virus (CDV) combination vaccine against virulent CDV challenge exposure, and to document lack of interference among the other modified-live virus (MLV) components. ANIMALS: 33 specific-pathogen-free (SPF) Beagle pups (7 to 10 weeks old). PROCEDURE: A canarypox virus recombinant-CDV combination vaccine was tested for safety and efficacy along with MLV components (canine adenovirus type 2, canine coronavirus, canine parainfluenza virus, and canine parvovirus) in 26 SPF Beagle pups. The combination vaccine was rehydrated with either Leptospira canicola-L icterohaemorrhagiae combination bacterin (vaccine 1) or sterile diluent (vaccine 2). An additional group of 7 seronegative SPF pups received the control MLV components devoid of the combination vaccine (vaccine 3). Two vaccinations were administered 21 days apart, either IM or SC. The dose of the combination vaccine used to inoculate these pups was 40 times lower than the recommended commercial dose. At 21 days after the booster vaccination, all pups were challenge exposed with a virulent CDV strain, then were observed for 21 days to record morbidity and mortality. RESULTS: Adverse local or generalized reactions were not induced by vaccinations. All vaccinates seroconverted to CDV. Serum antibody titers to MLV components were not different, with or without inclusion of the combination vaccine. After challenge exposure, morbidity and mortality in vaccinates were 0% (0/26); in control dogs, values were 100% morbidity and 86% mortality (6/7). Brain impression smear slides made from all dogs that did not survive challenge exposure were CDV positive by use of a direct fluorescein isothiocyanate method. CONCLUSIONS: The canarypox virus-CDV combination vaccine, administered SC or IM, is a safe product that elicits CDV seroconversion, does not interfere with other vaccine components, and protects vaccinated pups against virulent CDV challenge exposure.

Animals↗
PubMed1996

Ovulatory cycles and anovulatory periods in the addax (Addax nasomaculatus).

Changes in serum oestradiol and progesterone were measured to study their dynamics during ovulatory cycles in six female addax, an endangered antelope. Blood was collected three times per week, during chute restraint, for 3 months (November to February) before introduction of a male, and continued until pregnancy was diagnosed with ultrasound. Serum was analysed by enzymeimmunoassay. Mean luteal phase, interluteal phase, and cycle durations were 22.7 +/- 2.0, 8.78 +/- 0.5 and 32.3 +/- 1.7 days, respectively. Ultrasonography revealed coiled uterine horns and maximum follicle and corpus luteum diameters of 15 and 27 mm, respectively. Each female experienced an anovulatory period, during which oestradiol continued to fluctuate, but progesterone remained below 2 ng ml-1. These periods ranged from 39 to 131 days and were not synchronous; ovulatory cycles resumed spontaneously in all females. All four females placed with a male conceived. Because addax give birth all year round, they are not considered seasonal breeders. The sporadic periods of anovulation that occurred during the winter months of this study suggest a possible seasonal effect. However, systematic sampling has not been conducted during summer and early autumn and will be necessary to address this question.

Anestrus↗
PubMed1991

Combined aspirin and sulfinpyrazone in the prevention of recurrent hemodialysis vascular access thrombosis.

We carried out a pilot study in 15 hemodialysis patients with recurrent vascular access thrombosis to examine whether the combination of low dose aspirin (85 mg once daily) and sulfinpyrazone (200 mg three times daily) is safe and effective in the prevention of vascular access thrombosis. Hemostatic measurements were performed prior to and after four weeks of starting the drug combination. Baseline values for fibrinopeptide A were elevated in all patients while those for platelet factor 4, fibrinogen, antithrombin III and protein C were generally within normal limits. A major reduction in the frequency of vascular access thrombosis from 0.114 per month to 0.04 per month was noted during combined drug treatment (p less than 0.001). Although in vitro platelet aggregation to various stimuli was markedly suppressed and platelet thromboxane B2 formation was almost completely inhibited in patients on aspirin/sulfinpyrazone, this was not associated with a significant further prolongation of the bleeding time. A relatively high rate of complications, particularly mild gastrointestinal bleeding, was noted in patients on aspirin/sulfinpyrazone that could not be predicted on the basis of pre-treatment hemostatic test results.

Aspirin↗
PubMed1989

Motor vehicles as a site of accidental poisonings.

Although most poisonings occur within the home, the toxic agents involved are customarily transported there by motor vehicles. Over a 9-month period, all potentially toxic exposures reported to a poison information center that occurred in a motor vehicle were collected. Common toxins were identified and associated incidence and risk were assessed; 68% were pediatric exposures and the remainder were in adults. The adult exposures were dermal and via inhalation, whereas the pediatric exposures were predominantly inhalation (44%) and ingestion (36%). Inhalant toxins included carbon monoxide (CO) (13%), fire extinguishers (48%), and hydrocarbons (17%). Ingested toxins were comprised of medications (36%), automotive products (14%), and cosmetics (14%). 26% of the exposures were treated in Emergency Departments and the remainder at home. 79% of the patients were asymptomatic or had only a mild outcome; 21% suffered moderate toxicity. Toxic exposures in motor vehicles pose a significant threat to both driver and occupants. Children are at high risk from products improperly stored in the car (shopping bags, purses, glove compartment) and resulting from the care giver's inattention while driving. These results can be used to promote community awareness of this problem.

Accidents↗
PubMed1988

A programmable, computer-controlled cone-plate viscometer for the application of pulsatile shear stress to platelet suspensions.

Described is a special purpose cone-plate viscometer that is capable of acceleration or deceleration through a step change in speed in less than 0.7s. The speed of the rotating cone is controlled by a microcomputer which can be programmed to generate speed vs time ramp functions of variable slope. Prior calibration of motor power required to shear Newtonian fluids of known viscosity at various speeds provides the basis for determination of apparent suspension viscosity and enables the viscometer automatically to compensate for changing sample viscosity during shear. The viscometer was used to carry out a series of preliminary studies in which platelet-rich plasma (PRP) was subjected to continuous and pulsatile shear stress at 37 degrees C. Shear-induced platelet aggregation (SIPAG) was significantly greater in response to pulsatile versus continuous shearing except at the lowest applied stress (10 dyn/cm2). Increases ranged from about 40 percent at a stress amplitude of 25 dyn/cm2 to nearly 55 percent at dyn/cm2. This increasing trend with stress amplitude might be interpreted as a positive correlation between SIPAG and the loading rate. Dense granule release, as indicated by serotonin release, was dependent on both stress amplitude and number of pulses even at the higher stress where SIPAG was independent of pulse number.

Blood Platelets↗
PubMed1987

Deaggregation of in vitro-degranulated human platelets: irreversibility of aggregation may be agonist-specific rather than related to secretion per se.

Based on studies with thrombin, it has been proposed that human platelets exposed to strong release-inducing agents undergo irreversible aggregation and cannot be deaggregated without the use of proteolytic enzymes. We tested the hypothesis that irreversible human platelet aggregation occurs as a result of thrombin-specific platelet alterations rather than induction of the release reaction per se. Washed human platelets were exposed to either thrombin (THR) or the aminophospholipid N-(7-Nitro-2,1,3-benzoxydiazol-4-yl) phosphatidylserine (NBD-PS) for 20 seconds. Both agents caused similarly extensive release of platelet dense- and alpha-granule contents. After neutralization of thrombin and NBD-PS, and addition of PGE1 and apyrase, the platelets were sedimented, resuspended and incubated at 37 degrees C with gentle agitation. Single, disc-shaped, degranulated platelets which were recovered in both systems were capable of aggregation in response to a second exposure to aggregating and release-inducing stimuli. Deaggregation was more rapid, more extensive, and more reproducible with NBD-PS- than with THR-degranulated platelets. Platelets exposed to thrombin for longer than 20 seconds showed a progressive loss of deaggregability which was not observed after prolonged incubation with NBD-PS. These findings do not support the concept that extensive secretion per se causes irreversible aggregation of human platelets. Instead it appears that formation of irreversible linkages between platelets involves the specific, time-dependent interaction of THR with platelets, released fibrinogen and possibly one or more other substances secreted from platelets.

4-Chloro-7-nitrobenzofurazan↗
PubMed1986

Lung mechanics, cellularity, and surfactant after prenatal starvation in guinea pigs.

Prenatal starvation in the guinea pig causes reduced pulmonary diffusing capacity and retarded alveolarization among neonates. To study the impact of such starvation on biochemical and mechanical properties of the neonatal lung, pregnant guinea pigs were fed ad libitum throughout gestation or starved with 50% rations during their last trimester. Neonatal body weight was 35% less due to starvation, and dry lung weight, DNA, and protein contents were decreased 26, 36, and 31%, respectively (P less than 0.001 for all). Hematological data indicated no anemia, hypoproteinemia, or altered glucocorticoid levels due to starvation. Total surfactant phospholipids in these neonates were reduced 61% in lavage and 35% in the neonatal lung tissue, although surfactant compositions were similar to controls. Specific lung compliance in the air-filled lungs was not altered, but the saline-filled lungs were more distensible over deflation pressures of 9-18 cmH2O (transpulmonary). Although starvation retarded both lung cellularity and surfactant, only that portion of lung elastic recoil attributable to tissue forces was affected.

Animals↗
PubMed1985

Activation of human platelets by N-substituted aminophospholipids.

N-(7-nitro-2,1,3-benzoxadiazol-4-yl) phosphatidylserine (NBD-PS), a fluorescent phospholipid synthesized from phosphatidylserine by reaction with NBD-chloride, caused platelet shape change and aggregation when added at micromolar concentrations to suspensions of washed human platelets in the absence of added fibrinogen. Platelet aggregation by NBD-PS was accompanied by thromboxane synthesis and secretion of contents from dense, alpha-, and lysosomal granules in the absence of appreciable platelet damage. Indomethacin completely inhibited NBD-PS-induced thromboxane synthesis, but platelet aggregation and [14C]serotonin secretion were only slightly inhibited. Neither inhibition of the ADP-dependent pathway with creatine phosphate/creatine kinase plus ATP, alone or in combination with indomethacin, nor maximum elevation of cyclic AMP by treatment with prostaglandin I2 and theophylline completely inhibited NBD-PS-induced platelet aggregation or [14C]serotonin secretion. Platelet effects of NBD-PS were specific in that neither phosphatidylserine nor lyso-NBD-PS were similarly active. The activation of platelets by NBD-PS is not attributable to the NBD moiety exclusively since acylation of the amino group with 5-dimethylaminonaphthalene-1-sulfonyl-chloride yielded a similarly active derivative. Dansylated phosphatidylethanolamine was also active. The findings indicate that NBD-PS and other N-substituted aminophospholipids can activate a central pathway of platelet secretion and aggregation that is independent of released ADP and thromboxane formation and is only partially controlled by platelet cyclic AMP.

4-Chloro-7-nitrobenzofurazan↗
PubMed1982

Vaginal organic acids and hormonal changes in the menstrual cycle.

Twenty-seven women not using oral contraceptives (OCs) and 22 women using OCs were studied during one complete menstrual cycle. Twenty-four-hour vaginal secretions, collected on alternate days by a tampon method, were analyzed for acetic and other short-chain aliphatic acids and for lactic acid. Daily blood samples were analyzed for estrogens, progesterone (P), and luteinizing hormone (LH). No difference was found between OC users and nonusers in either amount or variability of vaginal aliphatic acids throughout the menstrual cycle. Aliphatic acids did not correlate with estrogen of P levels. A significant positive correlation was found between vaginal lactic acid and blood estrogens in those subjects not using OCs.

Adolescent↗
PubMed1982

Hyperprolactinemia and sexual disorders in men.

One hundred and thirty-six men, who presented at Masters & Johnson Institute for treatment of impotence, ejaculatory incompetence, and inhibited sexual desire, underwent endocrine screening. Eleven men (8.1%) were found to be hyperprolactinemic: three had a mild degree of hyperprolactinemia while eight had markedly elevated serum prolactin levels in conjunction with subnormal serum testosterone levels. The markedly hyperprolactinemic men, all of whom were subsequently found to have prolactin-secreting pituitary adenomas, presented with diverse histories of sexual disorders which were similar to those of men with psychogenic sexual dysfunctions. All eight experienced some degree of improvement of sexual function following a 2-week course of intensive psychotherapy, although full restoration of libido was contingent on reduction of circulating prolactin to normal or near-normal levels. Measurement of prolactin levels should be routinely performed in all men presenting with the above sexual disorders and depressed testosterone levels.

Bromocriptine↗
PubMed1981

Basal body temperature: unreliable method of ovulation detection.

Basal body temperature (BBT) charts for menstrual cycles of 98 women were evaluated by six experienced physicians. The time of ovulation as estimated from the charts by a consensus of at least five of the evaluators coincided with the luteinizing hormone (LH) peak +/- 1 day in only 17 (22.1%) of the 77 cycles that were determined by endocrine profiles to be ovulatory and to have adequate luteal phases. An additional 22.1% of these cycles were thought to have monophasic patterns by a consensus of the physicians. Extreme caution in interpretation is urged when BBT is used for clinical or research evaluations of ovulation or menstrual cycle dynamics.

Adolescent↗
PubMed1978

Failure of nocturnal prolactin suppression by methysergide to entrain changes in testosterone in normal men.

In order to investigate further the postulated relationship between the secretion of PRL and testosterone, 10 normal young men were studied during polygraphically recorded sleep. Concentrations of LH and testosterone were measured in plasma every 20 min, and the results were analyzed in relation to sleep parameters and previously reported (J Clin Invest 56: 690, 1975) concentrations of PRL. All subjects were studied on a control night after placebo administration and on an experimental night after ingestion of the serotonin receptor blocker, methysergide. Analysis of variance revealed that concentrations of testosterone rose gradually during sleep on both nights, as has been noted in previous studies. Highest LH values occurred during stage 1 sleep, but were only 25% higher than the lowest values, which were seen in stage 4. As shown previously, PRL concentrations were markedly suppressed by methysergide treatment. However, no significant change in testosterone values were observed on the methysergide nights as compared to the control nights. When the data were analyzed by a correlational approach, again, no significant relation between concentrations of PRL and testosterone was found. Although these data do not support the concept that PRL-stimulated testosterone secretion occurs during the night in normal men, this study does not rule out the possibility that such a mechanism may be operative during daytime hours, or under conditions of PRL stimulation rather than PRL suppression.

Humans↗
PubMed1975

An XX male: cytogenetic and endocrine studies.

A 3 year old black male with ambiguous genitalia had a 46, XY karyotype in a bone marrow culture and an intermediate buccal smear result, suggestive of a mosaic of chromatin positive and chromatin negative cells. Upon re-evaluation at age 15 years, he has a 30% positive buccal smear and a 46, XX karyotype in cultures of peripheral blood lymphocytes, skin fibroblasts, bone marrow, and testis. No Y-body fluorescence was detectable in interphase cells from the testicular biopsy or the various cultures. The testicular biopsy appeared similar to that of XXY males, and primary hypogonadism was documented by elevated LH (107 mIU/ml) and FSH (57 mIU/ml) levels in conjunction with low testosterone (142 ng/100 ml). Administration of hCG produced qualitatively normal acute responses of testosterone and estrogens. The cytogenetic data provide support for the theory that at least some XX males once had a Y-containing cell line which was subsequently lost.

Adolescent↗