Techniques for high-resolution MR imaging of atherosclerotic plaque

Atherosclerotic cardiovascular disease is the most common cause of death in the United States. Investigation of atherosclerotic plaque morphology and composition is important because the findings may be useful in predicting prognosis or response to therapy. This study presents high-resolution magnetic resonance (MR) imaging techniques developed on a 1.5-T whole-body imager with a custom-built surface coil, for characterizing the composition and morphology of plaque removed at carotid endarterectomy. The initial comparison of MR imaging and histologic results showed good correlation. In conjunction with MR angiography, these techniques could be used in in vivo imaging to define the size, location, and contents of atherosclerotic plaque at the carotid bifurcation.     

Necessary optimality conditions for a generalized problem of production scheduling

This communication concerns a derivation and study of necessary optimality conditions for production scheduling. The continuous-time optimal control problem is stated for the analysis of extremal behaviour of a flexible flow shop. This is accomplished by means of the maximum principle, which is applied to the problem with irregular constraints and three typical forms of objective function.     

Self-inflicted orbital and intracranial injury with a retained foreign body, associated with psychotic depression: Case report and review

Reports of intracranial self-multilation by psychotic individuals are associated with severe mental disorders, criminality, or both. We describe a psychotically depressed male who drove a ballpoint pen through his right medial canthus and into his intracranial compartment. The patient developed a cavernous sinus syndrome and a traumatic dissection of the cavernous portion of the carotid artery. The pen was removed intraoperatively. Postoperatively, the patient was placed on a course of broad-spectrum antibiotics, antidepressants, and antipsychotic medications, and he has received long-term psychiatric follow-up. The literature related to these unusual cases is reviewed, and relevant surgical, medical, and psychiatric aspects of treatment are discussed.     

Outcomes of 829 neonates with complete transposition of the great arteries 12-17 years after repair.

OBJECTIVE: Between 1985 and 1989, the surgical management of neonates with complete transposition (TGA) underwent a transition from atrial to arterial repair. We sought to examine the intermediate outcomes and their associated risk factors in neonates repaired during the era of transition. PATIENTS AND METHODS: Twenty-four institutions entered 829 neonates age less than 15 days in a prospective study. Diagnosis was simple TGA (n=631), TGA with ventricular septal defect (VSD) (n=167), TGA with VSD and pulmonary stenosis (TGA/VSD/PS) (n=30), or TGA with PS (n=1). Repair was by arterial switch (n=516), atrial repair (Senning=175, Mustard=110) or Rastelli (n=28). Time-related events were analysed by parametric hazard function modeling and incremental risk factors for mortality, re-intervention, and late functional assessment were sought. RESULTS: Survival estimates at 6 months, 5, 10, and 15 years are 85, 83, 83, and 81%, respectively. The hazard function for death after repair has two phases: an early rapidly declining phase and an ongoing constant one. Constant phase mortality is less likely after the arterial switch operation and in children with simple TGA. During follow up, at least one re-intervention was required in 167 children (pacemaker, n=35; percutaneous intervention, n=32; baffle re-intervention, n=27; re-operation, n=125). Freedom from re-intervention at 6 months, 5, 10 and 15 years is 93, 82, 77, and 76%, respectively. Of survivors, 87% have been followed up to the last 3 years, including an assessment of functional ability of 562 children (83%). Functional class 15 years after repair is class I in 76%, II in 22%, III in 2%. The proportion in functional class I decreased over time. Psychosocial deficits, especially learning disorders are prevalent. CONCLUSIONS: Survival 15 years after TGA repair is good with most children functioning well, and results are best after an arterial switch operation. There is an ongoing risk of death that is less after the arterial switch operation. With the exception of Rastelli patients, the likelihood of survivors needing re-intervention after 5 years is low. There is need for improved neurodevelopmental outcomes.     

Harvey Cushing's postoperative sketches of pediatric brain tumors

Harvey Cushing was a man of many talents. Not only was he a premier surgeon and scientist, but a prolific author and artist as well. In this paper, we present two postoperative sketches of pediatric brain tumors drawn by Dr. Cushing. These sketches are representative of drawings which accompany many of his operative notes at the Peter Bent Brigham Hospital. About 25% of Cushing's surgical sketches depict operations performed on children. The most commonly drawn childhood tumors were craniopharyngiomas and gliomas of the brain stem and cerebellum. These drawings reveal how Cushing maintained detailed records of his surgical experience. It is clearly evident from these records that Dr. Cushing gained substantial experience in the treatment of pediatric brain tumors.     

Simultaneous M-mode echoesophagram and manometry in the sheep esophagus

We report the simultaneous measurement of esophageal wall layer thickness and intraluminal pressure in the sheep esophagus using a miniature suction device incorporating a high-frequency ultrasound transducer and a manometry system. Transnasal placement of the device into the distal esophagus of a conscious sheep allowed observation of 133 swallowing events during three trials, each lasting from 45 to 60 minutes. In a fourth trial, 11 sequential dry and 23 sequential wet swallows were compared. Maximum manometric pressure, esophageal wall layer thickness, and duration of contraction were measured. All swallowing events produced simultaneous increases in intraluminal pressure and esophageal wall thickness. Mean maximal pressures were lower for dry swallows (18 ± 2.1 mm Hg) than wet swallows (22 ± 3.0 mm Hg) (p < .01). Thickness of the inner (circular) muscle layer increased above baseline by 124% for dry swallows and 161% for wet swallows (p < .01). We conclude that thickening of the esophageal inner (circular) muscle layer may be important in the generation of intraluminal esophageal pressure in the sheep esophagus. (Gastrointest Endosc 1995;41:582-6.)     

NGF Augmentation rescues trigeminal ganglion and principalis neurons,but not brainstem or cortical whisker patterns,after infraorbital nerve injury at birth

Prior studies indicate that neonatal nerve injury kills many trigeminal (V) first- and second-order cells, and interrupts pattern formation in the brainstem and cerebral cortex. Yet it is not known whether effects upon cell survival and pattern formation are causally related. To determine whether axotomized V ganglion cells can be rescued by an exogenous trophic agent, rats received 5 mg/kg of nerve growth factor (NGF) prior to, and every day after, infraorbital nerve section on the day of birth until sacrifice on postnatal day (PND) 1, 3, 5, 7, or 14. Other animals received identical lesions without NGF. Ganglion cell numbers were significantly reduced by PNDl in pups not given NGF, while NGF-treated rats displayed no significant cell loss through PND7. However, NGF did not permanently rescue V neurons because ganglion cell numbers were reliably reduced by PND14. Cell numbers in V nucleus principalis were reduced by PNDl in pups not given NGF, while NGF-treated animals displayed no cell loss through PND14. NGF's rescue of second-order cells is probably an indirect effect of NGF actions upon V ganglion cells because, in other newborns, NGF failed to maintain principalis cells after direct lesion of the left V ganglion. To determine whether preventing cell death permits whisker-related pattern formation, other rats also received NGF prior to and after infraorbital nerve section at birth. After 3–14 days, patterns were assessed in the brainstem and cortex with cytochrome oxidase histochemistry and serotonin immunocytochemistry. Whisker-related patterns failed to develop as in cases not given NGF. These data indicate that communication with the periphery is necessary for the maintenance of central whisker-related patterns. They also suggest that V ganglion cells can be rescued, albeit temporarily, from rapid injury-induced death by NGF, thereby delaying injury-induced cell death in nucleus principalis. However, the mechanism(s) responsible for injury-induced pattern alterations in the developing V system remains to be elucidated. © 1993 Wiley-Liss, Inc.