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Biomedical subjects

G B Davis

Publications and source records attributed to G B Davis.

At least 37 records · Page 2Linked to original sources
PubMed1988

Perfusion scan findings understate the severity of angiographic and hemodynamic compromise in chronic thromboembolic pulmonary hypertension.

Major vessel chronic thromboembolic pulmonary hypertension is potentially remediable by thromboendarterectomy. The diagnosis often has been delayed because a lung perfusion scan demonstrated modest defects thought to be incompatible with severe vascular obstruction. To define the relationships between perfusion scan abnormalities, angiographic findings, and hemodynamic data, we analyzed 25 consecutive patients with chronic major vessel thromboembolic pulmonary hypertension who subsequently underwent thromboendarterectomy. We found that the perfusion lung scan consistently caused us to underestimate the severity of pulmonary arterial obstruction as defined by pulmonary angiography. Furthermore, there was no significant correlation between the severity of hemodynamic compromise and the extent of obstruction defined by perfusion scan or angiogram. These findings suggest that, when pulmonary hypertension is known or suspected, the diagnosis of correctable, chronic major vessel obstruction should be pursued by angiography and hemodynamic assessment even though the perfusion scan may demonstrate only two segmental defects.

Adult↗
PubMed1987

Thrombosed dialysis grafts: efficacy of intrathrombic deposition of concentrated urokinase, clot maceration, and angioplasty.

Forty-one thrombosed polytetrafluoroethylene hemodialysis grafts in 26 patients were treated by a modified method of fibrinolytic therapy and transluminal angioplasty. The modifications included the use of highly concentrated urokinase, intrathrombic injection of urokinase into mechanically macerated thrombi, use of a crossed two-catheter technique, observation of the patient in the angiography suite during the entire procedure, and transluminal angioplasty to correct underlying stenosis immediately after partial or complete thrombolysis. Lysis was initially successful in 37 (90%) of 41 procedures. Successful treatment, defined as a functional graft for longer than 6 months without intervening surgery, was achieved in 16 (62%) of 26 patients. In comparison with previous transluminal or surgical regimens, this modified method permits marked acceleration of thrombolysis, immediate transluminal angioplasty, and sparing of potential future graft sites.

Angioplasty, Balloon↗
PubMed1986

A defect in thyroglobulin synthesis in an inherited ovine goitre: possible neonatal respiratory distress syndrome.

A ram lamb with congenital goitre showed signs of respiratory distress at birth. All previously affected lambs from this flock bad been born dead or bad died soon after birth. The serum free-thyroxine level at 1 birth was low (9.8 pmol/l) but treatment with oral L-thyroxine resulted in an increase in thyroxine blood levels to above normal and regression of the goitre. Four weeks after withdrawal of thyroid supplementation and when the lamb was eight weeks old, the radio iodide uptake mechanism of the thyroid glands was shown to be intact but the iodide was not organified. Low normal peroxidase activity was demonstrated in fresh thyroid tissue but gel electrophoresis demonstrated an absence of normal thyroglobulin from extracts of the goitrous thyroid. This lamb and the other affected lambs of this flock have an inherited defect in thyroglobulin synthesis and it is likely that the respiratory distress was associated with the low levels of thyroid hormone affecting foetal lung development.

Journal Article↗
PubMed1985

Renal osteodystrophy with facial hyperostosis and 'rubber jaw' in an adult dog.

A nine-year-old male Sheltie dog was presented with bilaterally symmetrical maxilliary swelling, loose teeth and flexible mandibles. The condition was progressive over a period of two months. Biochemical and histopathological examinations supported a diagnosis of renal osteodystrophy with facial hyperostosis and 'rubber jaw'.

Journal Article↗
PubMed1984

Tuberculosis in a kiwi (Apteryx mantelli).

Generalised tuberculosis was found in a captive kiwi (Apteryx mantelli) at autopsy. Sequential faecal sampling of the other kiwis and falcons (Falco novaeseelandiae) held in the aviary revealed an excretor of Mycobacterium avium.

Journal Article↗
PubMed1983

Case 43, Part I.

Explore the source record for details and available documents.

Adolescent↗
PubMed1983

Vaccination against ovine pneumonia: a progress report.

The results of three field trials of a live, cold-adapted, parainfluenza virus type 3 vaccine supported the hypothesis that infection with this virus initiates some ovine pneumonias. The serological response following vaccination was poor and only 22-44% of vaccinates developed a serum antibody response by two weeks after vaccination. Nevertheless, the prevalence of pneumonia was lower in vaccinated lambs in all three trials at the time that natural infection with PI3 was detected in the non-vaccinated lambs hut the differences were significant in only one trial. In some of the trials the number of deaths and the number of carcases downgraded or condemned because of severe pleural lesions were also lower and growth rates were higher in vaccinated lambs. The vaccine was specific for PI3; thus there was little effect on the prevalence of pneumonias occurring at other times in the absence of new PI3 infections. Nevertheless, this is the first direct evidence that any virus has a role in naturally occurring ovine pneumonias and the first indication that the prevalence of the naturally occurring disease may be reduced by vaccination.

Journal Article↗
PubMed1983

The prevalence and microbiology of pneumonia in a flock of lambs.

A flock of New Zealand Romney lambs on a property in Hawkes Bay was examined from August 1978 to June 1979. In November, the lambs in the flock were allocated to groups as follows: 600 lambs from which groups were selected for slaughter by commercial criteria each month (selected groups); 700 lambs which were subdivided into 8 groups (random groups), one of which was sent for slaughter each month; and 25 lambs to monitor serological responses to viral infections (surveillance group). At slaughter, lesions in the anterior lobes of the lungs were classified into small, large or mottled lesions while those in the posterior regions of the diaphragmatic lobes comprised a separate group. The prevalence of the pneumonic and pleural lesions was recorded in all groups of lambs. Pneumonic lesions in lambs from the random groups were further classified after microscopic examination. The prevalence of infections with parainfluenza virus type 3, adenoviruses, Mycoplasma spp., and Pasteurella haemolytica was also recorded in the random groups. Average carcase weights of all groups of lambs were also recorded. The prevalence of large lesions in the anterior lobes, pleural lesions and devaluation of carcases due to pleural lesions was significantly lower in the selected than in the random groups. In the random groups, the prevalence of small lesions in the anterior lobes of the lungs was high and was not always associated with infections with the viruses, P. haemolytica or Mycoplasma spp. Microscopically, these lesions could he divided into four types as previously described. The prevalence of large lesions in the anterior lobes was low in November but increased to peak levels in February and March and then declined to intermediate levels. The prevalence of large lesions was associated with that of infections with the micro-organisms and significantly more large lesions contained P. haemolytica and Mycoplasma spp. than did small lesions or normal lungs. The prevalence of large lesions also appeared to be inversely related to the average carcase weights of the lambs. Most large lesions were similar on microscopy to those of "enzootic" or "atypical" pneumonia but were divided into four types on the basis of exudative and proliferative features. The prevalence of mottled lesions in the anterior lobes was low throughout the period of observation but peaks were observed in January and May. The peaks were associated with adenovirus infection and elevated prevalence of infection with P. haemolytica and Mycoplasma spp. Significantly more mottled lesions contained P. haemolytica than did small lesions or normal lungs. Microscopically, most mottled lesions were similar to exudative large lesions. Lesions in the posterior diaphragmatic lobes were most numerous in November and from April to June. Their prevalence appeared to be related to anthelminthic treatment and environmental conditions. Microscopically, these lesions were typical of those following infection with Dictyocaulus filaria.

Journal Article↗
PubMed1983

Activation of Sendai virus infectivity by an enzyme in chicken amniotic fluid.

Sendai virus grown in LLC-MK2 cells is known to have low infectivity, no detectable haemolysing ability and predominantly uncleaved F glycoprotein. Treatment of such virus with chicken amniotic fluid resulted in a 10(3)- to 10(4)-fold increase in infectivity, the development of haemolysing ability, and cleavage of the F glycoprotein. The 'Sendai activating enzyme' (SAE) responsible for these effects required the presence of 1 mM-Ca2+ ions for maximum activity. It was inhibited by phenylmethylsulphonyl fluoride and soybean trypsin inhibitor but was unaffected by sulphydryl-blocking agents. The results of gel filtration tests suggested that the molecular weight of SAE was about 55 000. SAE may be the natural proteolytic activator of Sendai virus in a soluble form.

Allantois↗
PubMed1983

Streptokinase and transluminal angioplasty in the treatment of acutely thrombosed hemodialysis access fistulas.

Streptokinase was selectively infused into nine thrombosed hemodialysis access fistulas in eight patients. Lysis occurred in all but one case. Of the eight infusions producing lysis, seven resulted in some clinical benefit. Three grafts functioned adequately for 2 to 6 months after streptokinase infusion alone. A fourth patient had good function for over 11 months after streptokinase treatment and transluminal angioplasty. In a fifth patient, graft function was partially restored, but a persistent arterial defect led to elective graft replacement. Moderate fibrinolysis in the sixth case was of no clinical benefit; rethrombosis developed promptly after SK was discontinued because of bleeding from a recent puncture site. In cases 7 and 8, fibrinolysis restored arterial inflow to the graft, but surgery was needed to revise partially obstructed venous outflow. It is concluded that selective streptokinase infusion, with or without transluminal angioplasty and operation, is often effective in the treatment of acutely thrombosed vascular access fistulas.

Adult↗
PubMed1982

Arterioportal communications: observations and hypotheses concerning transsinusoidal and transvasal types.

Arterioportal shunting is observed angiographically in a wide variety of pathologic conditions. The route of flow has classically been considered to be via the hepatic sinusoids (transsinusoidal). This route occurs in cases of cirrhosis or the Budd-Chiari syndrome, and results in retrograde hepatofugal flow in portal branches. More recently, a transvasal route has been recognized angiographically, in which portal flow often remains hepatopetal. The transvasal route occurs in cases of hepatocellular carcinoma, metastases, shock, hepatic arterial obstruction, and many other conditions. Histologic confirmation of this route has been sought for many years, with other partial success. Nevertheless, angiographic evidence, as presented here, is sufficiently compelling to justify description of this pathway and its significance. Arterioportal flow may also occur via a post-traumatic fistula (disruption of adjacent portions of hepatic artery and portal vein), and via benign tumor vessels in hemangioma or hemangioendothelioma.

Adult↗
PubMed1982

Cholecystokinin cholecystography, sonography, and scintigraphy: detection of chronic acalculous cholecystitis.

Because the efficacy of cholecystokinin cholecystography in the detection of chronic acalculous cholecystitis remains in doubt, the procedure is rarely used in clinical practice. However, the ability to observe gallbladder contraction with sonography and 99mTc-para-isopropylacetanilido-iminodiacetic acid cholescintigraphy (PIPIDA) offers a possibility to improve the sensitivity of the test. To determine if the degree of gallbladder contraction after cholecystokinin is the same as measured by the three techniques and if it differs in symptomatic patients compared to the normal population, cholecystokinin cholecystography, cholecystokinin sonography, and cholecystokinin PIPIDA were performed in 10 symptomatic patients and 10 normal volunteers. The mean maximum contraction of the gallbladder during the three studies was 63%, 61%, and 68%, respectively, for the volunteers, and 72%, 63%, and 73%, respectively, for the patients. The mean maximum gallbladder contraction during all three procedures was 64% +/- 26% SD in the volunteers and 74% +/- 17% SD in the patients. The differences were not statistically significant. Although there was good correlation in the degree of maximum gallbladder contraction among cholecystokinin cholecystography, cholecystokinin sonography, and cholecystokinin PIPIDA, marked variation in both the volunteers and the patients makes it unlikely that the degree of contraction as observed by any of these techniques can be used to indicate the presence of chronic acalculous cholecystitis.

Biliary Dyskinesia↗
PubMed1981

Campylobacter colitis: a common infectious form of acute colitis.

A case of acute ulcerating colitis due to Campylobacter fetus is presented. The radiographic and endoscopic findings are indistinguishable from those of idiopathic acute ulcerative colitis. The clinical and bacteriological data relating to Campylobacter are discussed.

Adult↗
PubMed1981

Oriental cholangiohepatitis: preoperative radiographic and ultrasonographic diagnosis.

The recent influx of immigrants from Southeast Asia into the United States has increased the likelihood of encountering unusual diseases heretofore rarely seen in this country. Among these disorders is Oriental cholangiohepatitis, a potentially life-threatening process whose early diagnosis is facilitated by roentgenographic findings. Ultrasonography can also provide useful information, although potential pitfalls in diagnosis should be recognized.

Adult↗
PubMed1980

Angiomyoma of the palate.

Oral tumors of smooth muscle origin are rare. Most oral leiomyomas are believed to be derived from vascular smooth muscle. The leiomyomas are divided into angiomyomas and leiomyomas depending on the degree of vascularity. Differentiation must be made from neurofibromas and other spindle cell tumors, as well as leiomyosarcomas.

Hemangioma↗