A comparison of intravenous and intracoronary streptokinase in acute myocardial infarction

A randomised study of intravenous and intracoronary streptokinase therapy was carried out in 20 subjects with acute myocardial infarction and angiographically confirmed complete obstruction of the associated coronary artery. Two dose levels of therapy were used. Although more recanalisations occurred with intracoronary than intravenous therapy at the low dose levels, overall there was not a significant difference between the two groups; one million IU intravenously over 20 minutes recanalised four of five arteries. While seven of nine recanalisations with intracoronary therapy occurred within an hour, only two of five with intravenous therapy did so. Hence prolonged angiographic observation is necessary to document recanalisation with intravenous therapy adequately. Nevertheless, the time disadvantage of large dose intravenous therapy is not great and it may yet prove as effective as, and more practical than, intracoronary therapy.

Transvenous ablation of atrioventricular conduction for refractory or malignant supraventricular arrhythmias

In nine patients with recurrent disabling supraventricular arrhythmia refractory to, or intolerant of, multiple drug combinations, and two patients with Wolff-Parkinson-White (WPW) syndrome and documented malignant atrial fibrillation, transvenous ablation of atrioventricular (AV) conduction, utilising synchronised unipolar DC shocks delivered by catheter to the AV node-His bundle or to the accessory AV pathway, was attempted. One to two 200-300 J discharges produced complete heart block in all of the nine patients, with markedly improved symptomatic status at one to ten month follow-up including the one patient with recovery of modified AV conduction. Single 100-150 J shocks ablated pre-excitation for five to fifteen minutes in the two WPW patients without subsequent modification of accessory pathway conduction. There were no complications. This simple technique has great potential and may supplant some open-heart procedures. With refinement it may be possible to slow rather than to ablate AV-His conduction, to ablate conduction via accessory AV pathways permanently and to interrupt ventricular re-entrant circuits.

Cigarette smoking and ventricular arrhythmia in coronary heart disease

With use of 24-hour ambulatory electrocardiographic monitoring, the effect of 1 hour of cigarette smoking on cardiac rhythm in 73 patients with coronary heart disease was studied. Fifteen subjects had no arrhythmia; 37 subjects had fewer than 2 atrial or ventricular premature complexes (APCs or VPCs)/hour, with APCs possibly related to smoking in 2 and VPCs related to smoking in 1. Nineteen subjects had more than 2 VPCs/hour (range 4 to 368) and had 16 +/- 29 VPCs/hour (+/- standard deviation) less during than before smoking (p less than 0.05), associated with an increase in heart rate of 4.6 +/- 6.8 beats/min (p less than 0.01). In none of the 9 subjects with unifocal VPCs did multiform beats develop during or after smoking, whereas 3 of 10 subjects with multiform VPCs had only unifocal beats during and immediately after smoking. In 1 of these 19 subjects, frequent APCs developed during smoking. One other subject had frequent APCs unaffected by smoking and another had sinoatrial block, which disappeared during smoking on 1 of 3 monitorings. In conclusion, no sustained or high-grade ventricular arrhythmia was provoked by smoking; although APCs may have been related to smoking in a few persons, the frequency and complexity of VPCs tended to be reduced in these subjects with coronary artery disease.

Fluctuations in susceptibility to noise-induced temporary threshold shift as influenced by the menstrual cycle

The relationship between the menstrual cycle and changes in HTL and in TTS (from exposure to "magenta" noise at 115 dBA for 10 min) was studied bidaily over 40 days in 9 normal-hearing (HTLs less than or equal to 15 db at .5-8 kc/s) aged from 20-30 years. All HTLs pre- and post-exposure were estimated from interrupted-tone, fixed-frequency Bekesy tracings. The analysis used was a technique developed to study such biological rhythms, a least-squares regression to a cosine function. An F ratio from the bivariate normal distribution was used to evaluate whether significant fluctuations across sessions occurred either in pre-exposure HTLs (2-8 kc/s) or in TTS (2,3,4, and 6 kc/s). No effects were frequency-dependent. For the pre-exposure HTLs 24 of 63 total measures showed a significant (p less than .05) fluctuation, ranging from 1.6 to 6.8 db. For the TTS data, 14 of 36 measures showed a significant fluctuation, ranging from 2.4 to 9.1 db. In general, pre-exposure HTLs were highest (poorer hearing) and TTS was least during menses.

Glutaraldehyde: an alternative to formocresol for vital pulp therapy

Based on the limited results of this eight-week comparison of formocresol and glutaraldehyde, it would appear that glutaraldehyde may offer distinct advantages over formocresol, in the treatment of cariously exposed primary and young permanent teeth. In particular, due to its chemical structure, it is more active in fixing the surface tissues and is more rapidly limited in its depth of penetration through these tissues. Glutaraldehyde does not exhibit as significant an ability to induce the total loss of vitality, in the radicular pulp tissues. The progression of formocresol treated pulps to apparent fibrotic replacement via granulation-tissue ingrowth, through the apex, does not occur with the glutaraldehyde-treated pulp tissues. There may, however, be a slow progression of fibrotic replacement of the glutaraldehyde fixed tissue, in the coronal portion of the radicular pulp. Perhaps most importantly it would seem that since the glutaraldehyde does not perfuse the tissues to the apex, it will not demonstrate systemic distribution and other extradental phenomena, as have been identified with the use of formocresol

Histologic evaluation of gingival curettage facilitated by sodium hypochlorite solution

Gingival curettage has long been used as a modality in periodontal therapy. Recent longitudinal studies have shown that diligent curettage of periodontal pockets may aid in maintaining the attachment levels around periodontally involved teeth. This study was designed to histologically evaluate the controlled use of concentrated sodium hypochlorite solution to facilitate gingival curettage therapy. The results indicate that the action of sodium hypochlorite solution may be adequately controlled to provide predictable chemolysis of the soft tissue wall of a periodontal pocket with minimal effect upon the adjacent tissues. The action of the solution appears to have no detrimental effect upon healing. Reduction of inflammation prior to the procedure and careful technique are important to assure predictability. The use of gingival curettage augmented by sodium hypochlorite solution may aid in the management of patients undergoing periodontal maintenance.

Microvascular pressure distribution and responses of pulmonary allografts and cheek pouch arterioles in the hamster to oxygen

Despite extensive investigations of the pulmonary circulation using both in vitro and in vitro preparations, few direct microcirculatory studies have been made. Consequently, the mechanisms involved in the response of the pulmonary microvasculature to changes in oxygen tension remain unclear. The present study represents the first direct observation of the responses in pulmonary microvessels to alterations in oxygen tension. Neonatal lung tissue was transplanted into the hamster cheek pouch using a chamber technique. Both tissues were characterized with respect to their microvascular pressure profile and vascular response to hypoxia. The results showed the two tissues to be remarkably different. Small pulmonary and cheek pouch arterioles exhibited opposite responses to changes in oxygen environment; hypoxia elicited a constriction of pulmonary arterioles, but a dilation of cheek pouch arterioles. Pulmonary capillary pressure, although comparable to that measured in the intact lung (13 mm Hg), was substantially lower than cheek pouch capillary pressure, which was within the range of that described for several systemic vascular beds. The microcirculatory effects of oxygen on both tissues were confined to the arteriolar segments. The characteristics of this pulmonary microcirculation are such that it is a unique model for further physiological and pharmacological studies.

Responses of pulmonary allograft and cheek pouch arterioles in the hamster to alterations in extravascular pressure in different oxygen environments

The responses to changes in transmural pressure were investigated in pulmonary allograft and cheek pouch arterioles in two oxygen environments. Neonatal hamster lung tissue was transplanted into adult hamster cheek pouches. After vascularization (8-10 days), pulmonary and cheek pouch vessels were observed by intravital microscopy in hamsters anesthetized with pentobarbital. By gassing the suffusion solution (bicarbonate-buffered Ringer's) (pH 7.4 at 35-37 degrees C) with either low oxygen (95% N2/5% CO2) or high oxygen (75% N2/5% CO2/20% O2) and after sealing the top of the chamber, extravascular pressure was altered by varying the fluid volume of the closed chamber. Changes in arteriolar diameters in response to positive and negative square-wave pressure pulses were quantified using a video micrometer and close-circuit TV system. Pulmonary arterioles showed a passive dilation or constriction in response to increases or decreases in transmural pressure (+/-20 mm Hg). These responses were not altered either by changes in PO2 or nitroprusside. In contrast, cheek pouch arterioles showed myogenic responses by constricting when transmural pressure was increased and vice versa. These responses were potentiated at high PO2 and abolished with nitroprusside. It is concluded that a myogenic response is dominant in cheek pouch arterioles but not in pulmonary arterioles under these conditions. These latter observations are consistent with results obtained from isolated, intact lung.

Ratoon Stunting Disease of Sugarcane: Isolation of the Causal Bacterium

A small coryneform bacterium was consistently isolated from sugarcane with ratoon stunting disease and shown to be the causal agent. A similar bacterium was isolated from Bermuda grass. Both strains multiplied in sugarcane and Bermuda grass, but the Bermuda grass strain did not incite the symptoms of ratoon stunting disease in sugarcane. Shoot growth in Bermuda grass was retarded by both strains.

The syndrome of painful ophthalmoplegia. A case with intraorbital mass and hypervascularity

A patient diagnosed as having Tolosa-Hunt syndrome on clinical grounds was found by arteriography to have an intraorbital mass with hypervascularity. To our knowledge, this radiologic finding has not previously been reported in either Tolosa-Hunt syndrome or in the syndrome of orbital pseudotumor, and supports the proposition that these two conditions are anatomical variants of the same pathological process.

Pierce's Disease of Grapevines: Isolation of the Causal Bacterium

A Gram-negative, rod-shaped bacterium has been consistently isolated from grapevines with Pierce's disease. Grapevines inoculated with the bacterium developed Pierce's disease, and the bacterium was reisolated from the plants. The bacterium was serologically and ultrastructurallv indistinguishable from the one in naturally infected plants, and also indistinguishable from a bacterium isolated from almonds with almond leaf scorch disease.

Mast cell distribution in oral tissues of germ-free vs. conventional beagle dogs

Light microscopic examination of the mast cell distribution in various oral tissues in germ-free and conventional beagle dogs revealed no differences between the two animals. Mast cells were observed in all tissues examined, with an increasing order of incidence as follows: cervical lymph node, parotid and submandibular glands, marginal gingivae, buccal mucosa and the middle one-third of the tongue. All four types (round, oval, elongated, and pseudopodial) of mast cells cell shapes previously described in the literature were observed. The marginal gingivae associated with the mandibular, second bicuspids was examined by light microscopy and was classified as to degree of inflammatory involvement. In a comparison of germ-free and conventional animals, the distribution of the degree of inflammation proved to be random. Correlation between mast cell densities and the degree of inflammatory infiltration was not statistically significant. However, mast cells tended to decrease as the inflammation became more severe. Electron microscopic examination of mast cells in the buccal mucosa revealed no difference in morphology of cells from germ-free or conventional animals. Cytoplasmic granules were of two basic types, one exhibited an amorphous matrix of uniform density and the other consisted of laminated coils of various sizes and densities.

Trichinosis: severe myopathic involvement with recovery

A case of clinically severe trichinosis following ingestion of commercially prepared pickled pigs' feet is reported. An unusual finding on muscle biopsy was a larval count of 4,046 per gram of muscle, the second highest density of muscle invasion recorded to date. Survival has not been reported previously in patients with greater than 1,000 trichinae per gram of muscle. Complete symptomatic recovery followed combined corticosteroid and thiabendazole administration.

International dosimetry: an evaluation of treatment planning in clinical trials

A tissue-equivalent phantom containing thermoluminescent dosimeters was mailed in succession to Mount Vernon Hospital, Northwood, Middlesex, England, to Groote Schuur Hospital, Capetown, South Africa, and to Winnipeg General Hospital, Winnipeg, Canada, to determine the accuracy and consistency in treatment for carcinoma of the cervix under hyperbaric oxygen conditions. (Protocol of the Medical Research Council's Working Party on Radiotherapy and Hyperbaric Oxygen.) The data were analysed by the Radiological Physics Center, Houston, Texas, and substantiate uniformity at and between the participating institutions.