Distribution of SP- and CGRP-like immunoreactive nerve fibers in the lower respiratory tract of neonatal foals: evidence for loss during development

The lungs of neonatal foals contain many nerves immunoreactive for substance P and calcitonin gene-related peptide. These nerves are closely associated with the epithelium, bronchial and pulmonary vessels and the airway smooth muscle of all intrathoracic airways, including non-cartilaginous bronchioles. Activation of sensory nerves in the respiratory epithelium could thus potentially affect, via local axon reflexes, vascular and respiratory smooth muscle in neonatal equine airways. Nerves immunoreactive for these peptides are much more widely distributed within the lung than in adult horses; they may thus play a trophic role before birth, or contribute to the post-natal adaptation to breathing.     

Processing of frequency-modulated sounds in the cat's posterior auditory field

Single-neuron activity was recorded from the posterior auditory field (PAF) in the cortex of gas-anesthetized cats. Tone bursts and broadband complex sounds were used for auditory stimulation. Responses to frequency-modulated (FM) sounds, in particular, were studied systematically. Linear FM sweeps were centered around the best frequency (BF) of a neuron and had an excursion large enough to cover its whole frequency tuning range. Rate and direction of change of the FM sweeps were varied. In the majority of PAF neurons (75%) the FM response seemed not to be linear, i.e., their best instantaneous frequency (BIF) varied by more than one octave at different FM rates (FMR). When the difference between BIF and BF at each FMR was used as a measure of linearity, it was within one-third octave only at five or fewer FMR in most PAF neurons (74%). The majority of PAF neurons (70%) preferred moderate FM rates (<200 Hz/ms). Fifty-four percent of all neurons in this area showed band-pass behavior with a clear preference in the middle range of FM rates in at least one direction. Overall, neurons with high-pass behavior in both directions made up only a minor portion (22%) of PAF neurons. When both directions of an FM sweep (low-to-high and high-to-low frequency) were tested, 50% of the neurons were clearly selective for one direction, i.e., the response to one FM direction was at least twice as large as that to the other direction. This selectivity was not necessarily present at the preferred FM rate. In general, FM direction selectivity was equally distributed over FM rates tested. The selectivity of PAF neurons for the rate and direction of FM sounds makes these neurons suitable for the detection and analysis of communication sounds, which often contain FM components with a moderate sweep rate in a particular direction.     

Carcinoma in situ of the larynx

A retrospective study of carcinoma in situ of the larynx at the British Columbia Cancer Institute indicates that radiotherapy, using a tumoricidal dose of Co 60, is the treatment of choice for this condition. Between 1940 and 1972, 43 patients with carcinoma in situ of the vocal cords were seen. A follow-up of five years or more was possible in 28 of these cases. Twenty-two were treated primarily with a tumoricidal dose of radiotherapy. Twenty-one of the 22 were free of disease for at least five years. This study, therefore, shows a five-year cure rate of almost 100 percent for patients treated with radiotherapy. It also brings out two further points regarding carcinoma in situ of the larynx; namely, an apparent increase in its incidence, and the presence of co-existing invasive carcinoma in some cases. We feel that since the incidence of laryngeal carcinoma has not increased, this apparent increase probably represents a greater awareness by both the pathologist and the clinician. We have also achieved more accurate diagnosis since the introduction of routine microlaryngoscopy. The single radiotherapy failure in our series was due to failure to diagnose co-existing invasive carcinoma. This would seem to be the most likely cause of similar failures reported in the literature.     

Antioxidant function of the mitochondrial protein SP-22 in the cardiovascular system

The mitochondrial protein SP-22 has recently been reported to be a member of the thioredoxin-dependent peroxide reductase family, suggesting that it may be one of the antioxidant systems in mitochondria, which are the major site of reactive oxygen intermediate generation. The aim of this study was to examine whether SP-22 is involved in mitochondrial antioxidant mechanisms and whether its expression is induced by oxidative stresses, particularly those in mitochondria. The expression of SP-22 protein was enhanced by about 1.5-4.6-fold when bovine aortic endothelial cells (BAEC) were exposed to various oxidative stresses, including mitochondrial respiratory inhibitors which increased the superoxide generation in BAEC mitochondria. The expression of SP-22 mRNA increased 2.0-3.5-fold with a peak at 3-6 h after exposure to Fe2+/dithiothreitol or a respiratory inhibitor, antimycin A. BAEC with an increased level of SP-22 protein caused by pretreatment with mild oxidative stress became tolerant to subsequent intense oxidative stress. On the other hand, BAEC that had been depleted of SP-22 with an antisense oligodeoxynucleotide against SP-22 mRNA became more labile to oxidative stress than control BAEC. The induction of SP-22 protein by oxidative stress in vivo was demonstrated in an experimental model of myocardial infarction in rat heart. These findings indicate that SP-22 functions as an antioxidant in mitochondria of the cardiovascular system.     

Tuberculosis of the larynx

Laryngeal tuberculosis was diagnosed in two men, a 73-year-old man Dutch by birth and a 40-year-old one Turkish by birth. In the former patient it was probably primary tuberculosis, in the latter secondary (he had lung tuberculosis as well). The clinical picture was highly suggestive of laryngeal carcinoma in both patients. They both recovered with chemotherapy. Laryngeal tuberculosis may mimic laryngeal carcinoma. The diagnosis is based on Ziehl-Neelsen staining, culture and polymerase chain reaction (PCR) on Mycobacterium tuberculosis. Because laryngeal tuberculosis is highly infectious, the patient has to be nursed in isolation and people in his or her environment have to be screened. The response of laryngeal tuberculosis to chemotherapy is good.     

Chondrosarcoma of the larynx

Cartilaginous tumors of the larynx are rare, and of those reported, most are chondromas. To date, approximately 157 cartilaginous tumors of the larynx have been reported, but only 37 have been chondrosarcomas. A review of the records of the past 25 years (1948-1974) of the Johns Hopkins University Hospital and the Greater Baltimore Medical Center was made and revealed only two previous cartilaginous tumors, both chondromas. A case of an exceptionally large chondrosarcoma of the larynx which appeared as a neck mass invading the thyroid cartilage in a patient with a six-month history of hoarseness is presented. A complete review of the literature was made which shows that most chondrosarcomas occur in middle-aged males originating most often from the posterior cricoid lamina, next from the thyroid cartilage. Misdiagnosis has been a problem with low-grade tumors, and although wide local excision has been stated as being the treatment of choice, the authors emphasize the need for more aggressive surgery because of the high recurrence rate discovered in the literature.     

CT findings in chondroradionecrosis of the larynx

PURPOSE: Our goal was to describe the CT findings before and after radiation therapy in a series of patients with laryngeal chondroradionecrosis. METHODS: The CT studies obtained before and after radiation therapy in nine patients with the diagnosis of laryngeal chondroradionecrosis were reviewed retrospectively. RESULTS: CT scans revealed abnormalities in all patients. A variable degree of laryngeal soft-tissue swelling was seen in eight of the patients. In four patients, cartilaginous abnormalities were visible initially, and appeared in three of four other patients who had further follow-up CT studies. Six patients had involvement of the thyroid cartilage; collapse of the thyroid cartilage was seen in two cases and gas bubbles were visible adjacent to the thyroid cartilage in three cases. Four patients with involvement of the thyroid cartilage eventually underwent total laryngectomy, and one died suddenly in severe respiratory distress. In all three patients with arytenoidal involvement, anterior dislocation of this cartilage was seen; in two of these patients, the adjacent part of the cricoid cartilage showed some sclerosis. Two patients with arytenoidal necrosis (both with cricoidal sclerosis) kept a functional larynx. In one case, cricoidal sclerosis was seen in association with lysis of the thyroid cartilage. CONCLUSION: The CT appearance of laryngeal chondroradionecrosis is nonspecific, but the diagnosis can be strongly suggested in cases of sloughing of the arytenoid cartilage, fragmentation and collapse of the thyroid cartilage, and/or in the presence of gas bubbles around the cartilage.     

Rheumatoid nodules of the larynx

A 67-year-old woman with rheumatoid arthritis was hospitalized because of dysphagia and severe nodulosis. Over a two-year period the patient had been treated with methotrexate. A computed tomography (CT) scan of the neck showed a 2 x 2 cm large tumour behind the top left lateral thyroid cartilage. A biopsy taken during direct laryngoscopy showed it was a rheumatic nodule. Treatment with colchicine reduced the patient's dysphagia. As methotrexate is used increasingly in the treatment of rheumatoid arthritis and as this particular drug causes rheumatic nodules in five to 10 per cent of the patients, it must be foreseen that the incidence of nodules in the upper airways will increase.     

Functional damage of the larynx

INTRODUCTION: The basic mechanism of the development of functional voice disorders is an excessive collision pressure between the vocal folds during phonation, which occurs between the membranous folds, and/or the vocal processes. Functional-traumatic lesions of the vocal folds appear mainly at the junction between the anterior and the middle thirds of the vocal folds, slightly below the free edge. This is the "predilection site" of the vocal folds, which is the most active part of the vocal folds during phonation, and is therefore mostly exposed to functional-traumatic changes. This study is aimed at establishing the most frequent benign lesions of the vocal folds, which appear at the predilection sites of the vocal folds, and discussing their functional-traumatic aetiology. MATERIAL AND METHODS: During the past 10 years 1550 patients underwent various microsurgical procedures for benign lesions of the vocal folds. They were studied for the precise localization of the lesions by the use of indirect videostroboscopy or microstroboscopy, and direct microlaryngoscopy related to the technique which has been used in each particular patient. In this way an overall number of lesions was established, which were located at the predilection sites of the vocal folds, indicating their functional-traumatic aetiology. RESULTS: It has been established that 1068 lesions (68.6%) were located at the predilection site of the vocal folds (Table 1). Namely, these were nodular lesions, polyps, cysts, and haematoma. Contact hyperplasia appeared at the posterior third of the vocal folds due to a special mechanism of its development. DISCUSSION: Functional-traumatic lesions are mucous stranding, nodular lesions, polyps, cysts, contact hyperplasia and haematoma. All these lesions are either of functional origin or functional voice disorders which contribute, to some degree, to their development.     

Crohn's disease of the larynx

Extraintestinal involvement of Crohn's disease is becoming more readily identified. Laryngeal involvement by Crohn's disease, however, has been reported in only five cases in the medical literature. We present the sixth case as well as an analysis of the prior reports.     

Fungal infections of the larynx

Some generalizations regarding fungal infections of the larynx can be made. The reader is cautioned to refer to discussions of the individual infections for exceptions to these generalizations. For the most part, the mycoses are organisms of low pathogenicity emerging as opportunistic organisms thriving in a compromised host. The isolated fungal infections of the larynx reported are exceptions to the rule. Involvement of the larynx and other body sites outside the lung generally indicates a widely disseminated form of the disease. Fungal infections most commonly occur in the immunocompromised patient, including those afflicted with AIDS, cancer, leukemia, and other lymphoreticular neoplasms, patients on long-term corticosteroid therapy, patients with chronic systemic diseases, including diabetes mellitus and severe pulmonary disease, and patients who have undergone successful organ transplantation, which depends on immunologic suppression. Although specific fungi are characteristically found in designated endemic areas, the diseases may surface in remote areas in persons who have recently traveled through the endemic sites. The pathologic picture can be confusing, and pseudoepitheliomatous changes at times resemble malignancy. When atypical features occur in a patient with a suspicious history, special stains and cultures as well as skin tests and serologic studies may be helpful in establishing the diagnosis. For the most part, amphotericin B has been the mainstay of therapy, although the introduction of the newer azole drugs (ketoconazole, itraconazole and fluconazole) may present a breakthrough in the future therapy of these lesions. Ketoconazole has been proven efficacious in certain fungal infections. Itraconazole has recently been released for clinical use. Because of its lower incidence of toxic side effects, it may replace ketoconazole in the therapy of these diseases. Finally, fluconazole, taken orally, effectively crosses the blood-brain barrier; appropriate clinical trials may prove it to be an acceptable agent for those fungi commonly affecting the central nervous system.     

粉末冶金钛合金SP-700的制备

以Ti、Fe、Mo元素粉及60A140V中间合金粉为原料,通过混料、模压和真空烧结,制备粉末冶金SP-700钛合金,系统研究粉末原料、压制压力及烧结温度等工艺参数对合金相对密度、组织和性能的影响。结果表明,随着压制压力增加,SP-700压坯与烧结体的相对密度均提高;用平均粒度低、氧含量高的Ti粉为原料制备的压坯密度低,而烧结体密度高;烧结温度升高使烧结体密度略微增大。SP-700烧结体组织为晶界和晶内旺层片分布在β基体上;烧结体的性能受粉末原料及烧结温度的强烈影响。与Ti-6Al-4V合金相比,SP-700具有更加细小的组织和更优异的性能。制备SP-700烧结体的最佳工艺以及制品的性能参数为：采用低氧钛粉（0．15％O,平均粒度为73．6μm）,在500MPa压力下压制成形、在1260℃真空烧结5h;相对密度达96．3％,抗拉强度为1008MPa,屈服强度为931MPa,伸长率达4.3％。     

Oncocytic cysts of the larynx

Oncocytic cysts make up a pathologically well-defined sub-group of cystic lesions in the larynx. As a rule they originate from the ventricle and occur in middle-aged or elderly persons. Clinically these tumours are uncharacteristic. Such oncocytic cysts are interpretable as retention cysts rather than actual new growths. The question concerning their rare occurrence is discussed on the basis of 5 cases diagnosed within a period of 2 months.     

Foreign bodies in the larynx in infancy

Three cases of foreign bodies in the larynx are described. The mode of presentation, management, and the importance of early diagnosis to decrease the number and severity of complications are stressed.