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Biomedical subjects

W H Johnson

Publications and source records attributed to W H Johnson.

At least 91 records · Page 5Linked to original sources
PubMed1989

Spontaneous rupture of the esophagus: a 30-year experience.

This retrospective review of 34 patients with spontaneous rupture of the esophagus, which spans a 30-year period, attempts to identify areas in diagnosis and therapy that might alter the dismal prognosis. The diagnosis and definitive surgical repair of Boerhaave's syndrome were frequently delayed. Delay resulted in a significant increase in complication rates. Pain (85%) and vomiting (71%) were the only common historical events suggesting the diagnosis. Physical examination was of aid in the diagnosis in only the 9 patients (27%) who demonstrated cervical or mediastinal emphysema. The initial chest roentgenogram was abnormal in 97% of the patients, but was interpreted as "compatible with perforation of the esophagus" in only 27%. Esophagography was diagnostic in 23 of 24 patients in whom it was used. Thoracentesis was of little diagnostic aid, but pleural fluid pH was measured in only 15% of the patients. Prompt surgical repair, regardless of time after onset, appears to be the indicated therapy.

Adult↗
PubMed1989

Surgery for angina pectoris--historical aspects.

The history of surgery for ischemic heart disease is presented beginning with procedures to ablate nerves to the heart in the early part of this century. The evolution of surgical techniques to primary coronary artery bypass grafting is illustrated. Included are subtotal thyroidectomy, pedicle grafting of muscle, omentum, lung, stomach, and jejunum to the pericardium and heart, cardiopericardiopexy, ligation of the great cardiac vein, grafting from aorta to coronary sinus, implantation of arteries into the myocardium, coronary artery bypass grafting, and percutaneous transluminal coronary angioplasty.

Angina Pectoris↗
PubMed1988

Assessment of immunoregulation by cultured, pre-attachment bovine embryos.

The possibility that the viability of bovine embryos might be predicted by measuring their release of immunoregulatory substances during culture has been investigated. Bovine embryos between days 2 and 19 of gestation were cultured for 24-48 h, the embryo-conditioned medium was harvested and studied for suppression of PHA-stimulated bovine leukocyte cultures. Medium incubated in the absence of any conditioning tissues served as control. Artefactual immunosuppression was detected in incubated control material that could be attributed, in part, to the mixing of different tissue culture media, the type of plastic-ware employed for incubation and supplementation of media with additional L-glutamine. It was observed that day-2 to day-9 bovine embryos, cultured in medium able to support the lymphocyte proliferation assay, did not release immunosuppressive substances. Medium conditioned by day-10 to day-12 embryos produced variable immunosuppression while that conditioned by trophoblastic vesicles derived from day-14 to day-19 embryos was consistently highly suppressive. Since bovine embryo transfer is normally conducted at 6-8 days of gestation, it is unlikely that measuring the immunosuppressive products released from bovine embryos will be of value for predicting their viability.

Animals↗
PubMed1988

Reproductive performance of dairy cows following treatment with cloprostenol 26 and/or 40 days postpartum: a field trial.

One hundred and seventy Holstein Friesian cows were randomly assigned to receive either 500 ug cloprostenol or saline placebo on Day 26 postpartum followed by 500 ug cloprostenol or saline on Day 40 postpartum. Four treatment groups were formed: Group 1-saline (Day 26)/saline (Day 40); Group 2-cloprostenol/(Day 26) saline (Day 40); Group 3-saline (Day 26)/cloprostenol (Day 40); Group 4-cloprostenol (Day 26)/cloprostenol (Day 40). Double blind techniques were used in administering treatments and in assessing the response to treatment. Palpation of the reproductive tract per tectum and uterine biopsies were performed on 92 cows prior to each treatment at Day 26 and Day 40 postpartum. Progesterone concentrations were determined on milk samples collected prior to treatment. There were no significant differences among treatment groups with respect to services per conception, number of heats detected before first service and culling for infertility. Cloprostenol treatment at Day 26 appeared to delay the first estrus, but it reduced the number of days to conception after the first service. Cows receiving cloprostenol at Days 26 and/or 40 had a decreased calving-to-conception interval compared to controls (P=0.01). Sequential therapy with two doses of cloprostenol resulted in slightly better reproductive performance than either treatment on Day 26 or 40 alone. Treatment with cloprostenol resulted in a decrease in the subsequent incidence of pyometra (P<0.05). It is concluded that in the herd studied, cloprostenol therapy at Day 26 and/or 40 postpartum was beneficial to reproductive performance. Although it was anticipated that cloprostenol would be more effective in cows with elevated progesterone levels, the opposite was observed at the Day 26 cloprostenol treatment. Uterine biopsy at Days 26 and/or 40 had a detrimental effect on subsequent reproductive performance.

Journal Article↗
PubMed1988

Ultrastructural assessment of a blastocyst recovered from a cow with subclinical purulent endometritis.

A blastocyst was recovered from a cow with subclinical purulent endometritis from which Actinomyces pyogenes was isolated. Ultrastructurally the blastocyst appeared viable, although the zona pellucida and pervitelline cell debris were undergoing phagocytosis by neutrophils. An increase in lysosomal activity was observed in the inner cell mass, which may represent sublethal injury due to inflammatory alteration of the uterine milieu. It was concluded that the embryo was resistant to the bystander effect of the suppurative inflammation but that the altered uterine microenvironment may have caused sublethal blastocyst injury.

Journal Article↗
PubMed1988

The recovery of ureaplasmas from bovine embryos following in vitro exposure and ten washes.

Twenty-six unhatched embryos and ova were exposed to Ureaplasma diversum strain 2312 in vitro for 16 h and subsequently washed ten times. Fifteen of the embryos and their wash fluids were cultured for ureaplasmas. Of the remaining 11 embryos, six were incubated with rabbit anti-Ureaplasma immunoglobulin (RAI) and five were incubated with serum from naive rabbits(NRS), after which all were incubated with protein A gold and prepared for electron microscopy. On ultrastructural examination, ureaplasmas were observed on the outer surface of the zona pellucida of all 11 embryos. The ureaplasmas on the six embryos incubated with RAI were labeled with gold particles, while those on the five embryos incubated with NRS were not labeled. Ureaplasmas were recovered from all 15 of the cultured embryos and all of the first and second wash fluids as well as intermittently from the third, fourth, sixth, seventh, eighth and ninth wash but not fom the fifth or tenth wash. It was concluded that viable ureaplasmas adhered to the zona pellucida during in vitro exposure of bovine embryos and were not removed by ten washes.

Journal Article↗
PubMed1987

The effect of a peptide aldehyde reversible inhibitor of elastase on a human leucocyte elastase-induced model of emphysema in the hamster.

The peptide aldehyde Ro 31-3537, N alpha-(1-adamantanesulphonyl)-N epsilon-(4-carboxybenzoyl)-L-lysyl-L-alanyl-L- valinal, is a reversible competitive, hydrophilic, specific inhibitor of elastase. Its Ki against human leucocyte elastase is 6 x 10(-8) M. The effect of this compound has been studied on a model of emphysema in the hamster induced by multiple sequential intratracheal doses of human leucocyte elastase. Concomitant intratracheal dosing of 200 micrograms of inhibitor with the enzyme significantly reduces lung damage as measured by quasi-static lung compliance and by histological assessment of the emphysema.

Adamantane↗
PubMed1987

Pharmacological interventions for motion sickness: cardiovascular effects.

Motion sickness (MS) was provoked in healthy volunteers subjected to simultaneous rotation through the vertical axis with head movements (HM). Arterial blood pressure (BP), heart rate (HR) and forearm blood flows (BF) were intermittently monitored. Forearm BF was measured by venous occluding plethysmography. Rotation at 20 rpm and cyclic HM were continued for 10 min or until the subject requested cessation of HM because of imminent emesis. There were no consistent changes in BP or HR, but marked increases in BF were observed with MS. There was an inverse correlation between duration of HM tolerance and increments in BF. Antimotion sickness medications scopolamine:d-amphetamine (0.4:5.0 mg) or promethazine:ephedrine (25:60 mg) failed to significantly increase the duration of HM; the latter mixture, however, did significantly reduce the HM-induced-hyperemic responses. Administration of naproxyn (275 or 550 mg) did not significantly alter HM duration or BF responses. These studies suggest that BF changes may be an objective index of MS susceptibility.

Adult↗
PubMed1987

In vitro exposure of bovine morulae to Ureaplasma diversum.

Ureaplasma diversum has been associated with infertility in the cow experimentally and in naturally occurring cases. However, the pathogenic mechanism is undetermined. The purpose of this study was to determine whether ureaplasmas are pathogenic for bovine morulae in vitro. Twenty-one morulae were recovered from three superovulated, mature, Holstein cows six or seven days postestrus. The embryos were divided into three groups (A,B,C) and incubated for 16 hours at 37 degrees C in humidified air with 10% CO2. Group A was incubated in embryo culture medium alone, Group B was incubated in culture medium with sterile ureaplasma broth added and Group C was incubated in culture medium containing 1.7 X 10(6) colony forming units Ureaplasma diversum strain 2312. After incubation, the morulae were examined using an electron microscope. Structures morphologically identical to U. diversum were present on the outer surface of the zonae pellucidae of all the morulae exposed to the organism and none were present on the unexposed control embryos. No other morphological differences were observed in either the ureaplasma-exposed embryos or the two groups of control embryos. Ureaplasma diversum was isolated from three of the five embryos incubated in culture medium with sterile ureaplasma broth added. These three embryos were recovered from one donor cow which cultured positive for U. diversum from the vulva and flush fluid. This finding suggests that the contaminating organisms entered the embryo culture wells either in the embryo collection medium or attached to the embryos.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Asymmetric otolith function and increased susceptibility to motion sickness during exposure to variations in gravitoinertial acceleration level.

Von Baumgarten and his colleagues (23,24) have suggested that asymmetries in otolith function between the left and right labyrinths may result from differences in otoconial mass and could play a role in space motion sickness. Such asymmetries would be centrally compensated for under terrestrial conditions but on exposure to weightlessness the persisting central compensation would produce a central imbalance that could lead to motion sickness. We have used ocular counterrolling as a way of measuring the relative "efficiency" of the left and right otoliths and have compared the ocular counterrolling scores of individuals with their susceptibility to motion sickness during passive exposure to variations in Gz in parabolic flight maneuvers. The experimental findings indicate that large asymmetries in counterrolling for leftward and rightward body tilts are associated with greater susceptibility to motion sickness in parabolic flight.

Acceleration↗
PubMed1986

The use of real-time ultrasound rectally for early pregnancy diagnosis in sheep.

Three groups of ewes (n=64) were tested for pregnancy using a real-time ultrasound system rectally, beginning at Day 25 after breeding. The ewes were examined while standing, using a 5 mH(3) transducer designed for equine rectal use. Each examination required less than one minute and produced no apparent distress. The results of the test compare favorably with other methods of early pregnancy detection with a predictive value of a positive test of 97%, a predictive value of a negative test of 80% and an accuracy of 91%.

Journal Article↗
PubMed1985

A new class of inhibitors of human leucocyte elastase.

Studies of the inhibition of elastases at a molecular level have resulted in the identification of protected dipeptides which are reversible and highly specific inhibitors of human leucocyte elastase (HLE). These have been further developed by increasing their hydrophilicity and potency to give a new family of elastase inhibitors, typically N alpha-(1-adamantanesulphonyl)-N epsilon-(4-carboxybenzoyl)-L-lysyl-L-alanyl-L-valinal. These compounds are active in pharmacological models designed to detect compounds of potential therapeutic value in the treatment of emphysema.

Adamantane↗
PubMed1985

Damage to the middle ear and the inner ear in underwater divers.

Postmortem human tissue from recently deceased divers was processed histologically to assess any inner and middle ear damage that could have resulted from the effects of pressure during diving. The following new findings are particularly noteworthy. In one diver, ascent while breath holding resulted in the rupture of the ear drum and blood in the middle ear, in addition to pulmonary barotrauma. In a second diver, following inner ear decompression sickness, new bone growth, similar to that described earlier in experimental studies with the squirrel monkey, was observed in the arms of one of the semicircular canals. These observations are further confirmation that otologic disorders can be a serious threat to divers.

Barotrauma↗