The relationship between lung volume and standard scalar ECG parameters in normal subjects.

Although the relationship between abnormalities in the ECG and lung volumes has been well described in patients with chronic obstructive lung disease, little is known about this relationship in normal subjects. We investigated this relationship in normal, supine subjects at lung volumes ranging from residual lung volume to total lung capacity. We found that there was a significant right shift in the frontal axis with increasing lung volume. Over the precordium, R wave amplitude decreased mainly at the lateral leads and S wave amplitude increased chiefly at the anterior leads. These results are consistent with a normal vertical shift and clockwise rotation of the heart with increasing lung volume.

Changes in thecal and granulosa cell LH and FSH receptor content associated with follicular fluid and peripheral plasma gonadotrophin and steroid hormone concentrations in preovulatory follicles of mares.

Individual antral follicles from 11 horse mares were studied at three stages of the oestrous cycle to determine the characteristics of the presumptive ovulatory follicle. Mares were ovariectomized (ovex) during the late luteal phase on Day 14 after ovulation (Group 1) and on the 1st (Group 2) or 4th (Group 3) day of oestrus. Every follicle greater than 5 mm in diameter was dissected from each ovary; follicles greater than or equal to 15 mm in diameter were analysed separately while others were pooled by size for subsequent analyses. The presumptive ovulatory follicle possessed the following characteristics: in Groups 2 and 3 they were the largest in size; in all groups they contained the largest amount of protein in the granulosa cell component; they were the most vascular; they contained the highest follicular fluid oestradiol concentration; and they possessed the highest granulosa cell LH/hCG receptor content. In 9 mares, there was one such follicle present. In 2 mares, there were 2 such follicles present and one of these mares had a history of repeated double ovulations. The presumptive ovulatory follicle of Group 1 mares contained more thecal LH receptor than did non-ovulatory follicles. There were no differences in granulosa FSH receptor content amongst follicles, although smaller follicles tended to have increased FSH receptor content. Follicular fluid FSH and LH reflected peripheral hormone concentrations with follicular fluid LH being highest in presumptive ovulatory follicles of Group 3 mares. Follicular fluid progesterone concentrations tended to be higher in presumptive ovulatory follicles when compared with small follicles. Within a class of follicle, follicular fluid androstenedione and testosterone concentrations were lower in follicles of Group 1 mares than in follicles from Group 2 and 3 mares, reflecting endogenous stimulation of androgen biosynthesis by LH. Elevated follicular-fluid oestradiol occurred only in the presumptive ovulatory follicle with concentrations at least 30-50-fold higher than in non-ovulatory follicles. These results demonstrate that the presumptive ovulatory follicle in horse mares has been selected by at least Day 14 after ovulation and can be identified at this time by its various biochemical characteristics. Only after the first day of oestrus were physical characteristics such as size accurately able to predict ovulatory follicle status. These results clearly demonstrate the relationship between LH stimulation of androgen biosynthesis in vivo regardless of follicle size or status (ovulatory or non-ovulatory).(ABSTRACT TRUNCATED AT 400 WORDS)

Intrapericardial teratoma: a continuing challenge.

Intrapericardial teratoma is a rare entity that presents a diagnostic and therapeutic challenge. The authors describe the case of an 18-month-old boy with this condition who was successfully managed by resection of the mass. Computerized axial tomography, radionuclide scanning and angiography are important aids in the preoperative assessment of intrapericardial masses. However, all are nonspecific. Definitive diagnosis can only be established by thoracotomy, resection and microscopic examination of the specimen. The long-term prognosis is good.

The use of radioreceptor assay for the detection of pregnancy in the mare.

Jugular blood samples were collected between 42-45 days from the last breeding for measurement of pregnant mare serum gonadotropin (PMSG) and progesterone in 46 pregnant mares. A radioreceptor assay (RRA) was developed to measure human chorionic gonadotropin (hCG) and subsequently modified to measure PMSG. Highly purified hCG was iodinated using a lactoperoxidase enzymatic procedure and served as the labeled antigen for both the hCG and PMSG RRA. Standard curves were generated using purified hCG or PMSG. Bovine corpora lutea served as the receptor source. The assay was conducted at 37 degrees C for one hour with a total elapsed time from preparation of the luteal cell homogenate until final results were calculated of 2.5 hours. Twelve of the 46 mares failed to maintain their pregnancy, returned to estrus and reovulated after 45 days post-breeding (non-foaling mares). Thirty-four of the 46 mares delivered foals following a gestation of normal length. Mean concentrations of PMSG in the foaling mares was higher than in non-foaling mares. A concentration of 6.9 I.U. of PMSG/ml was used as the lowest concentration necessary for the confirmation of pregnancy. Five of the mares delivering foals had low concentrations of PMSG and were called non-pregnant. Thus, the incidence of false negatives by RRA was 14.7%. All of the non-foaling mares were correctly diagnosed non-pregnant for an error rate (false positive) of 0.0. Mare Immunological Pregnancy (MIP) tests on the 12 non-foaling mares indicated three false positives - an error rate of 25%. Of the 34 foaling mares, the MIP test indicated 8 inconclusive or false negatives, an error rate of 23.5%. At day 42-45, there was no significant difference in progesterone concentrations (determined by RIA) between foaling and non-foaling mares. RRA is a quick, accurate and quantitative method for measuring PMSG in the mare and can be used to diagnose pregnancy at 42-45 days post-ovulation. Plasma progesterone concentrations at this time were not associated with subsequent pregnancy maintenance as were plasma PMSG concentrations.

Validity of computer interpretation of the electrocardiogram.

Evaluation of the accuracy of computer interpretation of 2019 standard 12-lead ECG's has been carried out. In 762 records defined as normal by the cardiologist the computer agreed in 41%, found 49% with minor "abnormalities" and read 10% as having gross abnormalities.There were 1257 abnormal records. The computer read 43 of these as normal including five with infarction and three with LVH. Agreement in the various abnormal categories ranged from 31% to 85% and even after review disagreement remained in 33% of cases.

Surdo-cardiac syndrome: incidence among children in schools for the deaf.

This is a report on a survey of 1126 deaf children in three schools for the deaf in the Province of Ontario. One case of the surdo-cardiac syndrome previously reported is included. There were four other children who had a history of syncope but no prolongation of the Q-T interval on the ECG. It is possible that these may represent a variant of the syndrome. Five more children had a prolonged Q-T interval but no fainting spells.