Biomedical subjects
Publications and source records attributed to R F Young.
Vertebral hemangiomas have usually been treated by resection following preoperative arterial embolization. A case is presented in which no feeding tumor vessels were demonstrable angiographically. The tumor was resected by an anterolateral transthoracic approach without preoperative embolization. There was progressive postoperative improvement of the myelopathy.
Unilateral trigeminal tractotomy was carried out at the level of the obex, just rostral to the subnucleus caudalis, in five young adult Macaca fascicularis monkeys. The animals had been trained previously to perform a behavioral shock avoidance task in response to electrical stimulation of dental pulp and facial skin. Tractotomy produced an elevation in the stimulus strength which elicited escape behavior when facial skin was stimulated but not when the tooth pulp was stimulated. Unit activity, evoked by electrical stimulation of the tooth pulp and facial skin as well as innocuous and noxious mechanical stimulation of orofacial regions, was recorded from neurons in the trigeminal main sensory nucleus and the subnuclei oralis and interpolaris of the spinal nucleus 8 to 12 weeks after tractotomy. Primary afferent input to these nuclei is unaffected by the tractotomy which is located more caudally. The tractotomy interrupts primary afferent input into the trigeminal nucleus caudalis and also intranuclear connections between caudalis and the more rostral nuclei. Forty-one units contralateral and 47 ipsilateral to the tractotomy were studied. Thirty-six of the units responded only to low-threshold mechanical or electrical stimulation of orofacial zones, 46 were responsive to innocuous mechanical and electrical stimulation of orofacial zones and also to electrical stimulation of the dental pulp. Six units responded only to dental pulp stimulation. No statistically significant differences between the populations of neurons ipsilateral and contralateral to the tractotomies were found relating to the size or location of the peripheral receptive fields, latencies, thresholds, mean firing densities, or responsiveness to the various forms of stimulation. The behavioral results suggest that trigeminal relay neurons rostral to the obex are able to signal dental pain sensation, and the physiological studies confirm that the firing of such neurons is unaffected by tractotomy. The physiological studies demonstrate that the firing patterns of relay neurons activated by natural and electrical cutaneous facial stimuli and which are located in trigeminal brain-stem nuclei rostral to the obex are also not affected by tractotomy. The cutaneous facial analgesia observed after tractotomy thus appears to be due to deafferentation of relay neurons in trigeminal nucleus caudalis rather than to alterations in coding patterns in rostrally located trigeminal neurons due to interruption of the intratrigeminal pathway between the caudal and rostral nuclear groups.
Near the right end of phage lambda DNA, between gene Rz and the cos site, are 2050 bp of apparently non-coding DNA. We have cloned a lambda DNA fragment containing this DNA into a plasmid and constructed a deletion, omega l, extending from a site within the Rz gene to a site about 560 bp from cos. This deletion could be recombined into viable lambda phage at a frequency equal to that observed for the undeleted sequence. Recombinant phage lambda carrying the omega l deletion were demonstrated to have the same burst size and kinetics of phage production as undeleted lambda. The omega l deletion can be used to extend the capacity of lambda cloning vectors and to provide a region for the insertion of heterologous DNA which should exhibit controllable high level expression from the lambda late promoter, p'R.
Forty-eight patients underwent electrical stimulation of the brain for treatment of chronic pain between 1978 and 1983. Average pain duration prior to treatment was 4.5 years. Before selection for this procedure patients underwent pain treatment in a multidisciplinary pain center, intensive psychological and psychiatric evaluation, and assessment of pain responsiveness to intravenous administration of placebo, morphine, and naloxone. A total of 71 electrodes were placed in the 48 patients at a variety of stimulating targets, including the periaqueductal gray matter, periventricular gray matter, thalamus, and internal capsule. Seventy-two percent of patients experienced complete or partial pain relief. In addition, 59% of patients were able to discontinue narcotic usage. Twenty-five percent of patients returned to normal physical activities and another 33% showed marked improvement in functional capacity. Follow-up periods ranged from 2 to 60 months; with a mean follow-up period of 20 months. A variety of relatively minor complications occurred, but no mortality or permanent sequelae were experienced. No patient's pain was made worse as a result of electrical stimulation. Electrical stimulation of the brain offers a safe and relatively effective method for the treatment of chronic pain in appropriately selected patients, who are unresponsive to other forms of therapy.
The hospital records of 78 patients who underwent surgical therapy for fungal infections of the central nervous system (CNS) between 1964 and 1984 are summarized. Nine different fungal types were identified, but Coccidioides immitis and Cryptococcus neoformans accounted for most (67.1%) of the infections. A variety of clinical syndromes were seen, including chronic basal meningitis (45 patients), intracranial mass lesions (12 patients), and communicating hydrocephalus (six patients). Thirteen patients had rhinocerebral forms of fungal infection, and two presented with spinal involvement. Delays in diagnosis were frequent and ranged from 2 months to 11 years. In 31 patients the CNS lesion was the first indication of a fungal infection, and lesion biopsy or cerebrospinal fluid (CSF) examination confirmed the diagnosis. A total of 144 surgical procedures were carried out, including lesion biopsy or excision in 13 patients, primary CSF shunting in 22, and placement of an Ommaya reservoir for administration of intraventricular or intracisternal antifungal agents in 48. All patients received parenteral and, in some cases, intrathecal or oral antifungal chemotherapy in addition to surgical therapy. Overall mortality was 43.6% (34 deaths). With prompt diagnosis and treatment, the mortality rate was 39% whereas, when appropriate treatment was delayed, the mortality rate was 64%. An additional 14 surviving patients (17.9%) exhibited permanent morbidity due to neurological deficits, seizure disorders, or renal toxicity following treatment with amphotericin B. The combined mortality and morbidity rate was 62.8%. Clinical symptoms were resolved completely in 29 patients, although in 10 evidence of disease persisted and chemotherapy was continued. Fungal infections of the CNS are being recognized with increased frequency. It is suggested that a high index of suspicion, aggressive attempts to obtain a diagnosis, and early and vigorous therapy may reduce the unfortunate outcome seen in a relatively high proportion of patients with CNS fungal infections.
Five patients were treated in whom gas within an intracranial abscess cavity was identified by plain roentgenogram, computed tomographic scan, or both. Management by aspiration in three patients was unsuccessful. Total excision of the abscess cavity was eventually required in all five patients, and a persistent extracranial communication was identified and closed in each. One patient died secondary to transtentorial herniation and severe brainstem injury; the other four recovered fully. Although certain anaerobic organisms may produce gas in the absence of a communication to the outside of the body, such production is uncommon. Total surgical excision is recommended for gas-containing abscesses because it allows removal of the mass lesion and identification and closure of possible persistent extracorporal communication.
Eleven Macaque monkeys underwent a variety of lesions in the trigeminal afferent system; namely, tractotomy, rhizotomy, and radiofrequency destruction of various components of the bulbospinal trigeminal nuclear complex. Behavioral responses were evaluated before and after the lesions using a quantitative paradigm which measured lever-pressing in response to electrical stimulation of the dental pulp or facial skin, and by assessing adversive responses to facial cutaneous and intraoral pin-scratch. Thresholds for lever-pressing in response to cutaneous facial stimulation were elevated by tractotomy, elevated further by a combination of tractotomy and rhizotomy of the seventh, ninth, and 10th cranial nerves and cervical dorsal roots C1-3, and maximally elevated by complete radiofrequency destruction of the trigeminal nucleus caudalis. These lesions also abolished adversive responses to cutaneous facial pin-scratch. None of these lesion combinations, however, altered lever-pressing responses to dental pulp stimulation. Radiofrequency destruction of the trigeminal nuclei principalis, oralis, and interpolaris caused elevations of lever-pressing thresholds in response to dental pulp stimulation, and also smaller but statistically significant elevations on cutaneous electrical stimulation. Mild reductions in adversive responses to cutaneous pin-scratch were also produced by these rostral nuclear lesions, suggesting analgesia. The experiments suggest that primary afferent fibers for dental pain perception travel only in the trigeminal nerve and that these fibers relay via the trigeminal brain-stem nuclei principalis, oralis, and interpolaris. Primary afferent fibers for cutaneous facial pain perception travel in the trigeminal, facial, glossopharyngeal, and vagus nerves, and the upper cervical dorsal and ventral roots, and these afferents relay mainly in the trigeminal nucleus caudalis.
The evaluation and treatment of minor head injuries are reviewed, with particular emphasis on those problems of head injury commonly seen by family physicians. Clinical history, physical examination, and radiologic studies that are of value in diagnosing minor head injuries are highlighted.
Illness analysis, according to one aspect of the Parsons deviance framework, proposes dysfunction to the family system and society. Largely accepted for many years, there are important deficiencies of the conceptualization which are not present in another theoretical stance. This latter formulation focuses on adaptive responses of families to stress and can be envisioned as adding an emphasis on mutuality of family-illness encounters. It is offered as a tool for theoretical enrichment which can supplement the original framework, broaden the analytic base and be applied in clinical settings by practitioners in medical and therapy fields who wish to investigate positive versus negative consequences of the family-illness intermesh.
The cases of 2 patients with postoperative ventriculitis due to Bacillus species bacteria are presented. Bacillus licheniformis was isolated from one patient following removal of an intraventricular meningioma, and Bacillus cereus from another patient following placement of a ventriculoperitoneal shunt. Both isolates were resistant to a variety of antibiotics, but both were sensitive to gentamicin and chloramphenicol. These cases emphasize several points; (a) Bacillus species, usually thought to be nonpathogenic, may produce intracranial infections; (2) species identification is important for epidemiological purposes and for the selection of appropriate chemotherapeutic agents; and (3) in cases of suspected ventriculitis, chloramphenicol or gentamicin should be considered for Gram's staining revealing gram-positive bacilli. In addition, we recommend that when planning antibiotic prophylactic regimens, consideration should be given to including one of these agents to assure coverage of Bacillus species.
Two patients with intractable pain of the head and neck due to cancer underwent trigeminal tractotomy and rhizotomy of the ninth and 10th cranial nerves, as well as an upper cervical dorsal rhizotomy. Postoperatively, cutaneous analgesia ws present ipsilaterally in peripheral portions of the face and the neck, but paramedian facial regions and the oral mucosa were hypalgesic. The procedures had no significant effect on dental pain perception in these patients, as tested electrically and thermally. These results are similar to those in recent reports of dental sensation after trigeminal tractotomy in animals. The results raise questions about the validity of the commonly espoused hypothesis that trigeminal nucleus caudalis is the exclusive locus for processing of orofacial nociceptive information. The findings are consistent with the idea that the entire spinal trigeminal nucleus serves as a site for integration of pain-related information from orofacial structures that are supplied by afferent fibers in the fifth, seventh, ninth, and 10th cranial nerves and the upper cervical nerve roots.
The transport of protein molecules by axoplasmic flow has been used to trace axonal projections in the trigeminal system of the cat. Autoradiography with tritiated amino acid labeling of synthesized proteins and the transport of the enzyme horseradish peroxidase have been employed. The latter method has enabled demonstration of afferent axons within the portio minor, some of which are of cutaneous origin. The trigeminal "motor root" thus appears to be homologous with spinal ventral roots in possessing a potentially significant sensory function. The presence of such afferent fibers in nerve roots thought previously to have an exclusively motor function may explain instances of preserved sensation or failure to relieve pain following rhizotomy of the trigeminal portio major.
Trigeminal tractotomy near the level of the obex was carried out in 10 macaque monkeys. Behavioral responses were evaluated by a quantitative paradigm measuring lever-press responses to electrical stimulation of the dental pulp or facial skin, and by assessing facial response to cutaneous pin-scratch before and after the tractotomy. Two pharmacological agents, strychnine and L-dopa, were administered and their effect on behavioral responses to these stimuli was studied. Tractotomy did not produce dental analgesia. Thresholds for escape from cutaneous electrical stimulation of facial skin, however, were elevated, consistent with marked hypalgesia to pin-scratch. The adversive responses to pin-scratch were absent in peripheral portions of the face, but near the midline and inside the oral cavity they were usually decreased or normal. Pharmacological agents caused a reduction in escape thresholds to cutaneous electrical stimulation and a shrinkage or abolition of the zone of analgesia to pin-scratch. The results imply that trigeminal nucleus caudalis, which undergoes deafferentation by tractotomy, may not be essential for processing of nociceptive information from the teeth, oral cavity, and midline facial zones. This findings is contrary to long-held hypotheses concerning facial pain mechanisms. The ability of strychnine and L-dopa to alter nociceptive escape thresholds is consistent with the idea, suggested by Denny-Brown, that facial nociception depends on central summation in the entire spinal trigeminal nucleus from overlapping afferent inputs contained in the trigeminal nerve, other cranial nerves, and the upper cervical nerve roots.
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Four cases of acute cerebellar hemorrhage in childhood are reported. Two were related to the rupture of arteriovenous malformations, one was a hemorrhage within a cerebellar tumor, and one (in a neonate) was of an undetermined etiology. Three of the cases were treated surgically, whereas the neonatal hemorrhage was managed medically. The latter case seems to be the only reported case of acute cerebellar hemorrhage in childhood that resolved spontaneously. Computed tomographpy proved to be invaluable in the diagnosis, management, and follow-up of the patients. Although surgical treatment is indicated when identifiable lesions cause the hemorrhage, nonsurgical approaches may be satisfactory when lesions are not discernible. Our cases, in addition to those reported previously, suggest a better prognosis for children than for adults with acute cerebellar hemorrhage, regardless of the etiology.
Spinal neurological complications caused the admission of 17 patients with achondroplasia to the UCLA affiliated hospitals between 1955 and 1979. These patients constituted 41% of all achondroplastic patients admitted during that period. The spinal stenotic syndromes could be divided into three groups: Group I: thoracolumbar stenosis (10 patients); Group II: foramen magnum and upper cervical stenosis (five patients); and Group III: generalized spinal stenosis (two patients). Eleven patients underwent a total of 18 decompressive operative procedures for treatment of paraparesis, quadriparesis, sensory deficits, and sphincter dysfunction. Excellent results were obtained with patients in Group I and II, 77% of whom were ambulatory and continent postoperatively. Two patients in Group III fared less well, showing steady neurological deterioration despite multiple operative procedures. The spectrum of spinal neurological manifestations secondary to achondroplasia is reviewed. Problems with conventional radiological studies and the potential role of computerized tomographic analysis of such patients are discussed. Recommendations for surgical technique are made. Early recognition, prompt clinical evaluation, and safe and accurate radiological analysis of spinal neurological complications of achondroplasia will allow appropriate decompressive surgical procedures to be performed. Excellent results may be anticipated in the reversal and prevention of neurological deficit secondary to achondroplasia with such an approach.
Metastases to the spinal epidural space with compression of the spinal cord or cauda equina are commonly encountered by physicians in a variety of clinical field. In the recent past, decompressive laminectomy followed by radiotheray was thought to be the best available treatment. More recently, radiotherapy alone has been advocated as an alternative treatment mode with a similar rate of effectiveness. This study compares laminectomy followed by radiotherapy to radiotherapy alone in the treatment of spinal epidural metastases in a randomized, prospective clinical trial. No significant difference was found in the effectiveness of the two treatment methods in regard to pain relief, improved ambulation, or improved sphincter function. Patients with an incomplete myelographic block fared well regardless of treatment, and those with a complete block fared poorly. Because of the limited size of this study and because of certain unforeseen design defects, the results are suggestive but not conclusive. Suggestions are made for a future randomized, prospective multicenter study that would conclusively answer the perplexing question as to the most efficacious method for treating spinal epidural metastases.