Biomedical subjects
R A Holmes
Publications and source records attributed to R A Holmes.
Lines from the president. Alliance not reliance.
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Effects of repeated Strongylus vulgaris inoculations and concurrent ivermectin treatments on mesenteric arterial lesions in pony foals.
Eight of 10 pony foals reared under helminth-free conditions were inoculated PO with 50 Strongylus vulgaris infective larvae/week for 4 weeks, at which time 1 foal died of acute verminous arteritis. Inoculation of 7 remaining foals continued at 2-week intervals for 20 weeks. Of the 7 foals, 3 were treated with ivermectin (0.2 mg/kg of body weight) in an oral paste formulation at experiment weeks 8, 16, 24; 4 foals were not treated. Two foals were not inoculated or treated and served as controls. After the first ivermectin treatment, ivermectin-treated foals had fewer days (12 +/- 2.9) with rectal temperatures greater than 38.6 C than did nontreated foals (23.3 +/- 3.8). Mean baseline rectal temperatures were 38 +/- 0.2 C. Adverse clinical reactions to ivermectin treatment were not observed in foals. Foals were euthanatized and necropsied 3 weeks after the last ivermectin treatment (week 24). Ivermectin was effective in reducing S vulgaris arterial larval and intestinal adult parasite numbers by 100% in 3 treated foals. Strongylus vulgaris arterial larvae and/or adults were recovered from all 4 nontreated inoculated foals. One nontreated inoculated foal lacked arterial larvae or active arterial lesions, indicating that protective resistance had developed in this individual. Marked gross and histopathologic lesions typical of chronic S vulgaris infection were observed in the 3 nontreated inoculated foals with arterial larvae. Repeated killing of intra-arterial S vulgaris fourth-stage larvae in ivermectin-treated foals did not exacerbate lesions associated with verminous arteritis or induce unique lesions associated with repeated destruction of arterial larvae.(ABSTRACT TRUNCATED AT 250 WORDS)
Sequential mesenteric arteriography in pony foals during repeated inoculations of Strongylus vulgaris and treatments with ivermectin.
Semiselective mesenteric arteriography was performed at regular intervals (inoculation weeks [IW] 0, 11, 18, and 24) in 9 of 10 pony foals raised to be free of parasites. Fifty infective larvae (L3) of Strongylus vulgaris were administered weekly for 4 weeks, then every 2 weeks through the 20th week. Three ponies were given ivermectin (oral paste, 0.2 mg/kg of body weight) treatment at IW 8, 16 and 24. Four ponies were inoculated, but did not receive ivermectin, and a third group of 2 ponies acted as uninoculated controls. Control ponies did not have gross or arteriographic lesions, whereas the inoculated untreated ponies had gross and progressive arteriographic lesions typical of verminous arteritis. Arteriographic lesions in the ivermectin-treated inoculated ponies were not as severe those in the untreated inoculated group, and there was either a partial resolution or a lack of progression of arteriographic lesions in all treated ponies. One untreated inoculated pony did not have progressive arterial lesions as did the 3 others in the group, and may develop resistance to the parasite.
Recurring tetraparesis attributable to a heartworm in the epidural space of a dog.
Recurring nonambulatory tetraparesis caused by a heartworm in the epidural space was diagnosed in a dog. On myelography and digital subtraction imaging, the parasite appeared as a large extradural mass. Surgical removal of a mature, female Dirofilaria immitis resulted in resolution of the neurologic signs.
Coexistence of cerebral infarct and arteriovenous malformation demonstrated by Tc-99m HMPAO and Tc-99m RBC SPECT imaging.
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Diagnosis of a liver abscess with Ga-67 and radiocolloid tomography.
A 46 year-old white male with fever of unknown origin demonstrated a multiloculated hepatic cyst on abdominal CT. Persistent fever and leukocytosis prompted Tc-99m Sulfur colloid liver-spleen and gallium-67 citrate imaging to identify a possible liver abscess. SPECT imaging provided pertinent clinical information that allowed the diagnosis of abscess to be made.
Discordant radioaerosol/radioperfusion in drug-induced maternal pulmonary edema.
A case of pulmonary edema in a 34-year-old pregnant woman on corticosteroids and beta adrenergics yielded an unusual radioaerosol/radioperfusion lung image. The image showed normal perfusion but multiple bilateral penetration defects on the radioaerosol study. Factors contributing to this unique pattern include the combined action of corticosteroids and beta-adrenergic agonists, local airway irritation caused by the drying effect of nebulized oxygen, sepsis, or a combination of these factors.
Human pharmacokinetics of samarium-153 EDTMP in metastatic cancer.
Samarium-153 ethylenediaminetetramethylene phosphonic acid ([153Sm]EDTMP) has been proposed to palliate pain resulting from osteoblastic metastatic bone cancer. Encouraging results in dogs with primary malignant bone cancer provided the catalysis for human biodistribution studies in five patients with metastatic skeletal carcinoma. The objective was to assess the preferential localization of [153Sm]EDTMP in bony lesions and compare it to the 99mTc-labeled phosphonates. Blood clearance of [153Sm]EDTMP was rapid with minimal accumulation in nonosseous tissues. Both radiopharmaceuticals showed identical lesion uptake in 23 paired lesions (p greater than 0.05). This indicates that the two radiopharmaceuticals concentrate in metastatic skeletal lesions by the same mechanism and since [153Sm]EDTMP emits beta radiation it may be therapeutically useful in ameliorating metastatic bony cancer pain.
Aneurysmectomy prognosticators by equilibrium multi-gated cardiac blood pool scintigraphy.
Non-invasive assessment of left ventricular aneurysm (LVA) resection prognosticators was obtained in 13 multigated cardiac blood pool scintigrams by applying Fourier analysis to identify regions of interest. Results were compared to contrast ventriculograms performed at recent cardiac catheterization. Excellent correlation of the contractile section ejection fraction (CSEF) was found between the two techniques, r = .92 (P less than or equal to .0001). The CSEF correlated inversely with the left ventricular end diastolic pressure (LVEDP), r = .83 (P less than or equal to .0004), implying that LVEDP is not an independent prognosticator. The relative LVA size expressed as a fraction of the left ventricle in end diastole (LVASF) correlated less strongly with LVASF derived from contrast ventriculography, r = .67 (P = .012). This was probably due to additive inherent errors in contrast ventriculography geometric assumptions. Paradoxical stroke steal fraction (PSSF) defined as the reverse stroke lost in the LVA divided by the left ventricular forward stroke, was calculated from subtraction images. We propose a resectability score utilizing the product of the scintigraphically derived CSEF X LVASF X PSSF X 1,000 to obtain non-invasive pre-operative prognostication of LVA resection and post-operative evaluation.
Retention of [99mTc]-d,l-HM-PAO in rat brain: an autoradiographic study.
The regional cerebral distribution pattern of [99mTc]-d,l-HM-PAO in rat brain was studied by autoradiography. The regional cerebral uptake of this tracer is related to regional cerebral blood flow (rCBF); however, the ratio of retained radioactivity (determined by digital imaging techniques) in gray matter compared to white matter is lower than that reported for the blood flow ratio. Considerable inhomogeneity is observed in cortical gray matter for at least 60 min postinjection, demonstrating that minimal, if any, cerebral redistribution of this agent occurs.
Serendipitous detection of intrarenal abscesses on technetium-99m MDP imaging while evaluating a foot ulcer.
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Mastocytosis: scintigraphic findings with bony involvement.
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Microcomputer-based digital image analysis system for quantitative autoradiography.
A computerized image processing system utilizing an IBM-XT personal microcomputer with the capability of performing quantitative cerebral autoradiography is described. All of the system components are standard computer and optical hardware that can be easily assembled. The system has 512 horizontal by 512 vertical axis resolution with 8 bits per pixel (256 gray levels). Unlike other dedicated image processing systems, the IBM-XT permits the assembly of an efficient, low-cost image analysis system without sacrificing other capabilities of the IBM personal computer. The application of this system in both qualitative and quantitative autoradiography has been the principal factor in developing a new radiopharmaceutical to measure regional cerebral blood flow.
Kinetic analysis of technetium-99m d,1-HM-PAO decomposition in aqueous media.
Technetium-99m-d,1-hexamethylpropyleneamine oxime [99mTc]d,1-HM-PAO) is a neutral-lipophilic chelate formed from a kit in high yield by stannous reduction of Na99mTcO4-. Of three methods used to analyze the purity of the 99mTc complexes, a single strip method using ether as the developing solvent was the most rapid and simple to perform. The lipophilic chelate converts to 99mTcO4- and other hydrophilic products with time and this limits the useful lifetime of the preparations. The rate of decomposition of [99mTc]d,1-HM-PAO increased in the presence of excess stannous ion and at pH greater than 9.
Echocardiogram calculations for the dog using Lotus 123.
A microcomputer (IBM-PC or compatible) program using the spreadsheet program, Lotus 123 was developed to calculate the 95% confidence intervals for the normal canine echocardiographic dimensions. Other cardiac function parameters are also calculated, but confidence intervals have not been determined.
Indocyanine green pharmacokinetics calculations using Lotus 123 spreadsheet.
Indocyanine green (ICG; Cardio Green, Hynson, Westcott & Dunning, Baltimore, MD) is a cholephilic dye that is commonly used as a liver function test. In order to obtain the pharmacokinetic values of ICG needed for liver function determinations, a linear and a log-linear regression must be done in addition to other calculations. Results can be obtained graphically, but are not as accurate as mathematical calculations. To obtain accurate results and expedite calculation time, a program was developed using the Lotus 123 spreadsheet program (Lotus 123, Lotus Development Corporation, Cambridge, MA) and an IBM compatible computer to do these calculations.
The production of 99mTc-labeled conjugated antibodies using a cyclam-based bifunctional chelating agent.
A bifunctional chelating agent (BFCA) based on a macrocyclic amine, cyclam, was used to form specifically 99mTc labeled rabbit-anti-HSA-antibodies. This study demonstrates the feasibility of forming a highly stable cyclam-based 99mTc-BFCA with its subsequent conjugation to antibodies.