Biomedical subjects
Publications and source records attributed to R E Kennedy.
We demonstrate an ytterbium gain band self-induced modulation instability laser. A highly nonlinear holey fiber is used to provide the anomalous dispersion required for bright soliton generation at 1 microm. The all-fiber integrated source yields a 40 GHz train of 4 ps pulses at a wavelength of 1064 nm.
We report on the development of a 2.5 microm core photonic crystal fiber with a substantially reduced water-peak loss around 1.38 microm, which allows extended Raman-soliton supercontinuum generation up to 1.55 microm with a cw ytterbium fiber laser pump source. The resulting broadband, high-spectral-power-density, low-coherence light source can be employed for advanced, submicrometer resolution optical coherence tomography.
We demonstrate an ultrashort all-fiber-integrated chirped-pulse amplification system yielding 1-ps pulses with 20 kW of peak power. 40-ps initial pulses generated by an externally modulated laser diode are chirped by self-phase modulation in a conventional fiber, amplified, and compressed in 110 m of air-core photonic bandgap fiber. The compressed pulses are frequency doubled in a periodically poled KTP crystal with up to 48% efficiency and applied to supercontinuum generation in a holey fiber, resulting in a high-power uniform continuum that stretches from 430 to 1450 nm.
1. The localization of choline acetyltransferase messenger RNA has been studied using a digoxigenin-tailed complementary oligodeoxynucleotide probe for in situ hybridization. 2. Putative cholinergic cells of the rat and ferret spinal cord and the ferret retina were labeled. 3. This technique affords superior resolution compared to radioactively labeled probes, with apparently equal sensitivity.
Facial asymmetry and cosmetic deformity can occur following enucleation. The effect of enucleation on the growth of the orbit can be demonstrated in the rabbit and cat by early enucleation, X-ray study and dry skull measurements. In 42 human patients the anophthalmic orbital changes are determined by roentgenograms. The influencing factors of age and the use of implants are discussed as to changes in the rim, orbital walls and volume, and optic foramina measurements. Growth retardation due to roentgen ray therapy and other clinical aspects are considered which would influence the appropriate clinical management.
Indications for the mutilating operation of exenteration are enumerated. They usually involve a malignant neoplasm of the orbital contents, primary, direct extension, or adnexal tissue that cannot be controlled by simple excision or irradiation. Surgically, subtotal exenteration with partial preservation of lids and even conjunctiva may be achieved occasionally. However, total exenteration may be lifesaving. Techniques and precautions are discussed. Advantages and disadvantages of skin grafting that influence the post-operative care are noted.
Nonocular melanoma rarely metastasizes to the orbit. We report the case of a melanoma presumably arising from an axillary lymph node sinus that metastasized to the left medial rectus muscle causing proptosis, diplopia, and reduced saccadic velocity measurements. Clinical, radiographic, and histopathologic data are presented and discussed.
Between 1982 and 1987, 32 patients with severe aortorenal atherosclerosis had simultaneous aortic and bilateral renal revascularization. All patients were hypertensive. Eighteen patients (56%) had renal insufficiency with a mean serum creatinine (SC) of 2.8 mg/dl. Nine patients had an aortic aneurysm; the remaining 23 patients had aortoiliac occlusive disease of varying severity. Aortic reconstruction was done with either a straight (six patients) or bifurcated (26 patients) Dacron graft. Renal revascularization was accomplished with either bypass (60 arteries) or transaortic endarterectomy (four arteries). One patient died of pulmonary embolism (operative mortality rate 3%). Beneficial blood pressure response was achieved in 28 of 31 survivors, (90%). Among the 18 patients with renal insufficiency, mean SC was 2.80 +/- 1.18 mg/dl preoperatively and 1.65 +/- 0.48 mg/dl postoperatively (p less than 0.001). Among eight patients with severe renal dysfunction before surgery (SC greater than 3 mg/dl), mean SC was 3.90 +/- 0.85 mg/dl before and 1.79 +/- 0.69 mg/dl after operation (p less than 0.001). In follow-up extending to 58 months (mean 27.6 months), five late deaths occurred; cumulative survival was 94% at 2 years and 60% at 4 years. There were no instances of worsening hypertension; one patient had deteriorating renal function. These results indicate that severe aortorenal atherosclerosis can be managed with simultaneous aortic reconstruction and bilateral renal revascularization at low operative risk. In addition, there can be high expectation of significant and persisting benefit in both hypertension and renal dysfunction after operation.
While the number of orbital surgeons is limited, it is hoped these can be recognized and patients referred to them by ophthalmologists not interested or trained in that specialty. Let the orbital surgeon determine whether he can handle the problem in 1 to 2 days, or whether a neurosurgeon should do the procedure or make it a joint effort. It may well involve other specialty team effort approaches. It is essential to have an understanding of x-rays, CT, angiography, and MRI techniques and films. Sit with these specialists to learn more and help to avoid negative, misdiagnosis reports in the interest of the patient. Use judgement in helping the patient decide on ophthalmic or the more extensive neurosurgical approach after careful study and what is in their best interest. The team approach is used in well established medical centers with the ophthalmologist and neurosurgeon (or other specialist) working together in the best interest of the patient. This is more interesting and keeps the ophthalmologist in the mainstream of medicine.
Eight hundred twenty clinical orbital cases have been reviewed as seen over a 34-year period. These are tabulated as to classification, numbers, and percentages. They include biopsy-proven (450 cases) and other clinical cases. These are patients seen by ophthalmologists practicing in an average community area rather than a large referral center and thus may be more truly representative of what might be encountered in practice. Any series has a certain bias. The advantage of a biopsy-proven series is recognized for the certainty and prognostic aspect. A clinical series represents a wider practical correlation and may include cases not likely to be biopsied, such as hemangioma. It is hoped that the percentage figures of these types of cases will help the clinician in his diagnostic evaluation of patients with orbital lesions. In this series 34% of the orbital lesions were malignant which warrants an aggressive approach for such cases rather than conservative supervision. Because of the very limited number or absence of some types of cases even in a large clinical or biopsy-proven series, I feel it warrants the development of a standard classification of lesions to be used by everyone. Also, assembling the data on infrequent types of lesions from a number of medical centers would give a much larger series and would have a more meaningful prognostic significance. This might be accomplished through one of our national ophthalmologic societies.
The extremely rare occurrence of sibling brothers with left pulsating exophthalmos has been presented with very similar plain film and CT scan findings. Other patients presented demonstrate the strong familial trend of neurofibromatosis, the multiplicity of lesions, the progression of lesions. Genetic counseling is indicated, together with educating the patient and family as to further neurologic deficits which may develop. On-going evaluation at intervals is indicated. Significant cases should only be approached surgically with the realization of the seriousness of what both the patient and doctor may encounter. Surgery, unfortunately, usually cannot offer much help. An interdisciplinary approach with the surgeon, plastic surgeon, neurosurgeon, and ophthalmologist offers a safer approach.
Indications for the mutilating operation of exenteration are enumerated. They usually involve a malignant neoplasm of the orbital contents, primary, direct extension, or adnexal tissue that cannot be controlled by simple excision or irradiation. Surgically, subtotal exenteration with partial preservation of lids and even conjunctiva may be achieved occasionally. However, total exenteration may be lifesaving. Techniques and precautions are discussed. Advantages and disadvantages of skin grafting that influence the postoperative care are noted.
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A patient with multiple orbital hemangiomas benefitting from the adjunct treatment of transcatheter selective arterial embolization has been presented. The interdisciplinary team effort for this relatively new modality of treatment is called to the attention of the ophthalmologist for consideration in management with difficult or inoperable orbital vascular lesions or arteriovenous malformations with or without intracranial manifestations.
Decreased orbital development following enucleation is a well recognized condition in the young person and is lessened by orbital implantation at the time of inital surgery. Pfeiffer, some 30 years ago, suggested that bone changes as well as the soft tissue changes could also continue to take place in the adult resulting in added orbital changes. While this has been questioned, the findings originally reported by Pfeiffer are firmly substantiated by roentgenograms and documented in this report. If there has been a significant interval of time following the enucleation, careful roentgenographic evaluation prior to cosmetic oculoplastic revision of the orbit should be done even in the adult.
Biochemical and electron microscope studies were conducted to determine the effects of traumatic shock on rabbit alveolar macrophages. Both resting and phagocytosing macrophages from the shocked animals, in comparison to comparable control macrophages, showed increased release of acid phosphatase from the cells into medium upon incubation in vitro, but decreases in the total content of acid phosphatase and beta-glucuronidase. Studies by electron microscopy showed ultrastructural alterations in macrophages from shocked animals consisting of a reduction in the number or a complete absence of lysosomes and, in some cases, increased amounts of rough endoplasmic reticulum and free ribosomes. In vitro incubation of macrophages from shocked animals with Pseudomonas aeruginosa showed that the process of bacterial ingestion was not impaired nor were the numbers of bacteria ingested decreased as compared to control macrophages. However, the ability of macrophages from shocked animals to destroy ingested bacteria appeared to be significantly altered. Extensive degradation of Pseudomonas was observed within phagocytic vacuoles of control macrophages after 15 minutes of incubation. In contrast, the majority of ingested organisms in macrophages from shocked animals showed no evidence of degradative changes.
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