Biomedical subjects
Publications and source records attributed to M E Morton.
Therapeutic measures used in the management of osteoradionecrosis (ORN) of the jaws are reviewed with reference to clinical case material. The development of rational treatment regimes designed to deal with the underlying pathological problem are discussed.
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Cerebrospinal fluid dynamics were studied in eight dogs during normal, hydrocephalic, and postoperative phases. Radionuclide-labeled substances introduced into the normal ventricular system flow out of the exits from the fourth ventricle to the convexity subarachnoid spaces superiorly to be absorbed in the sagittal sinus, and basorostrally to the exits from the perineural olfactory sheath into the nose to produce physiological cerebrospinal fluid (CSF) rhinorrhea. Serial radionuclide ventriculography of the head following intraventricular isotope injection of labeled proteins and chelate into the kaolin-induced hydrocephalic system shows a high degree of ventricular stasis with no perineural olfactory nerve flow (rhinorrhea). An operative transcerebral fistula, fashioned from a dilated lateral ventricle to the convexity subarachnoid space, reestablishes perineural olfactory flow of CSF into the nose, as demonstrated by the radionuclide ventriculography studies. This suggests a potential method for treatment of hydrocephalus. Serial imaging studies in this surgically modified system clearly demonstrate radionuclide flow through the patent fistula to distal absorption sites, thereby bypassing the basal obstruction. Moreover, augmented CSF pressures associated with obstructive hydrocephalus can be controlled by such treatment. The application of this method in treating clinical hydrocephalus is discussed with emphasis on fistula arachnoid closure to assure fistula patency.
A rare case, where excessive pneumatization of the sphenoid sinus resulted in a clinically obvious swelling of the temporal region and proptosis of the globe on the affected side, is reported. The relevant literature is discussed.
The diagnostic accuracy of hepatobiliary radionuclide imaging using 99mTC-labeled para-isopropyl acetanilido-iminodiacetic acid (99mTc-PIPIDA) in patients with hepatobiliary disorders was assessed in 50 patients. Thirty of the study group were jaundiced; the remaining 20 had other clinical features suggestive of some hepatobiliary disorder. The findings using PIPIDA proved to be correct in 22 (73%) of the 30 jaundiced patients and in 18 (90%) of 20 patients without jaundice. There appears to be a close relationship between the diagnostic accuracy of the test and the level of serum bilirubin. Thus, the diagnosis indicated by the PIPIDA test was correct in 30 (88%) of 34 patients in whom the serum bilirubin was less than 5 mg./dl. but only in 10 (62%) of 16 patients whose serum bilirubin exceeded 5 mg./dl. It is concluded from these observations that: 1. PIPIDA is diagnostically useful in the evaluation of hepatobiliary disorders, especially when the serum bilirubin is less than 5 mg./dl. and 2. the accuracy of this test is not absolute and the findings are not always definitive.
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Eight normal dogs were studied and then made hydrocephalic (kaolin induced) to demonstrate and compare the use of R131ISA and 99mTcDTPA in cerebrospinal fluid (CSF) bulk flow studies. The radioisotopes were simultaneously injected into the CSF space in the cisterna magna of normal dogs and into the lateral ventricles of hydrocephalic dogs after an equal volume of CSF had been removed. The average dose of RISA was 100 muCi, and for TcDTPA it was 7 mCi. A bag of lactated Ringer's solution (500 ml) was used as a control phantom after being injected with the same dose of isotope as used in the animals. Brain scans were obtained with the gamma ray camera at 4 and 24 hours after injection. We used four criteria to evaluate results: clinical state of the animal, CSF ventricular pressures with challenges, percentage of retained isotope in counts per minute, and ventricular size at postmortem examination. The results demonstrate that the amount of isotope retention over 20 hours and the clinical state of the dog are better correlated when RISA is used than when TcDTPA is used. The study indicates that RISA is more reliable than TcDTPA as an indicator of CSF bulk flow in both normal and hydrocephalic dogs.
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Cardiac output, renal and hepatic blood flows, arterial lactate concentration, and minute volume were measured before, during, and after 40 min of rest induced either by the practice known as "transcendental meditation" (TM) or by an ordinary eyes-closed rest-relaxation period. Two groups of normal young adults were studied: one group consisted of regular practitioners of TM and the other of similar individuals studied prior to learning this technique. Marked declines of renal blood flow were noted in both groups. Decline of hepatic blood flow, increased cardiac output, decreased arterial lactate, and minute volume were also recorded in the TM-induced rest period. These changes imply a considerable increase of nonrenal, nonhepatic blood flow during TM (44%) and, to a lesser extent, during rest (12%). Increased cerebral and/or skin blood flow is hypothesized to account for part of the redistributed blood flow in the practitioner.
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Two patients subjected to cardiopulmonary resuscitation with chest massage and direct-current cardioversion had positive activity on myocardial scintiscans using radioactive 99mtechnetium pyrophosphate. Possible explanations are offered, and recent reports of false-positive findings on scans due to organic disease, as well as iatrogenic causes, are discussed briefly.
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To determine the relationship between minimal increases in pulmonary wedge pressure (PWP), arterial PO2s, single breath diffusing capacity (DLCO), and lung perfusion pattern (as determined by semiupright lung scans), we elevated PWP by 61.8+/-4.1% from baseline values of 5.5+/-0.4 mm Hg. At the end of 30 min PaO2 increased by 13.2+/-1.4% (p less than 0.001) from baseline values of 81.7+/-3.1 mm Hg; DLCO decreased by 15.5+/-1.2% (p less than 0.01) to 0.98+/-0.10 ml/min/mm Hg/kg. Lung perfusion changes in the right lung apical zone increased by 28.0+/-4.2% (p less than 0.001) and decreased in the basal zone by 6.2+/-0.8% (NS). In the left lung the apical perfusion increased by 14.9+/-1.1% (p less than 0.01) and basal perfusion decreased by 8.6/+-1.4% (NS). We conclude that minimal elevation of PWP in dogs leads to improvement in PaO2s through alterations in the lungs perfusion pattern.
In an attempt to determine whether dehydration (intravascular fluid depletion) alters the radiologic or histologic picture of segmental Streptococcus pneumoniae pneumonia, we induced pneumonia in 2 groups of dogs, group 1 (normally hydrated) and group 2 (dehydrated). Five hours after the intrabronchial instillation of a brain-heart-Streptococcus pneumoniae mixture, all chest radiographs of dogs in group 1 and 2 were compatible with segmental alveolar pneumonia. Histologic lung sections obtained as early as 2.5 hours after infusion of the brain-heart-Streptococcus pneumoniae mixture revealed intra-alveolar edema with a minimum of leukocytes. By 24 hours after infusion, both groups showed marked intra-alveolar collections of edema fluid, fibrin, and leukocytes. We conclude that in a canine model, moderate dehydration has no effect on the radiologic or histologic features of Streptococcus pneumoniae pneumonia.
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