External Parathyroids Research Articles

HISTOLOGICAL STUDY OF THE THYROID AND PARATHYROID GLANDS IN IRAQI BUFFALO "BUBALUS BUBALIS" WITH REFERRING TO THE SEASONAL CHANGES

The present study included the collection of thyroid and parathyroid glands from the abattoirs of middle of Iraq in Summer and Winter seasons 2006-2007. The samples were fixed by 10% formalin and processed by the routine histological techniques, then stained by H and E, PAS and Van Gieson stain, then studied under light microscope. Dimensions were measured by ocular micrometer. Analysis of data was done by T-test. The most striking result declared that the thyroid gland showed no differences in histological characters between both seasons as the buffalo was poor thermoregulator animal. It is tempting to speculate that the thyroid gland provide an adaptive advantage for survival of the buffalo in the nature arid environment. The parafollicular cells (C-cells) were sparse and found singly in the thyroid glands. Flat dark nuclei of myoepithelial cells were recognized around the thyroid follicles. This study was referred to the presence of accessory thyroid gland which contains simple follicular epithelium, and little amount of the colloid. Our current study revealed the presence of internal and external parathyroids. The oxyphilic cells in the internal parathyroid gland were not observed. Note: this work in part of Master Science Thesis, submitted to the College of Veterinary Medicine, Baghdad University.

Topography and identification of the parathyroid glands in the calf.

There is considerable controversy in the literature concerning the topography of the parathyroid glands in the calf. In the present study, the position of the parathyroids III (external parathyroids) and of the parathyroids IV (internal parathyroids) was examined in 25 young calves, 10 veal calves and 5 adult oxen. Detailed data for the recognition and the collection of these glands are provided. The parathyroids III are well suited for removal in a fresh state, since they can readily be located. They are situated medial to the carotid bifurcation and ventrolateral to the vagus nerve, where the latter gives off the cranial laryngeal nerve. In all young calves and in most veal calves, they lie embedded in the sub-basilar portion of the thymus, from which they can usually be differentiated easily by their color. However, they should not be confused with lymph nodes and hemal nodes, which are located in the neighborhood. Light-microscopical substantiation is therefore advisable. The parathyroids IV are not suited for collection, since they cannot be distinguished macroscopically from the adjacent thyroid gland.

Uptake of3H-labelled Toluidine Blue and Neutral Red in the Parathyroids of the Dog

The parathyroid uptake of 3H-labelled toluidine blue and neutral red following i. v. injection in dogs has been studied. At different time intervals, the external parathyroids and samples from reference organs were removed for radioactivity determination. The mean uptake ratio per gram parathyroid/ thyroid of toluidine blue was approximately 3. The mean ratio of para thyroid concentration to that of blood and muscles was 10:1. For neutral red, the mean parathyroid/thyroid ratio was 1.3:1. It is suggested that 75Se-labelled toluidine blue may prove useful as a scanning agent for the parathyroids.

Some Results of Parathyroidectomy of Calves1,2

Summary This was a study of reactions of calves to removal of the internal parathyroids along with the thyroid glands, removal of the external parathyroids, and thyroparathyroidectomy. When only the internal parathyroids and the thyroid glands or the external parathyroids were removed, there was no tetany and little effect on the serum calcium and plasma inorganic phosphorus. Thyroparathyroidectomy resulted in an abrupt, marked lowering of the serum calcium, a less marked lowering of the inorganic plasma phosphorus, tetany, and death. An elevation of the inorganic plasma phosphorus occurred just prior to death.

TUMORS OF THE PARATHYROID GLAND

During recent years the parathyroid glands have come into rather special prominence owing to their apparent functional connection with calcium metabolism and tetany. In consequence, parathyroid tumors, instead of being pathologic curiosities, have assumed a more important clinical role. I have recently observed two cases of these fairly rare tumors, but before giving the details I will give a short synopsis of the present clinical aspects of the parathyroids and their pathology. The parathyroids were first accurately described in 1880 by Sandstrom, 1 who apparently, however, held the view that they were undeveloped embryonic thyroid tissue. In 1898, Gley 2 showed that tetany following parathyroidectomy did not occur unless the external parathyroids were removed, although they were still considered as part of the thyroid gland. The parathyroids may be intrathyroid or extrathyroid. According to Guleke 3 the human parathyroid may occur in three types: (1) the compact type, as seen

RELATION OF THE PARATHYROIDS TO THE HEALING OF A FRACTURE AS CONTROLLED BY THE ROENTGEN RAYS

Since Sandstrom's discovery of the external parathyroids in 1880, the parathyroid glands have been discussed extensively. There are two schools of thought, one being that these glands influence calcium metabolism, and the other that they exert a detoxicating effect on guanidin bodies. The balance of opinion seems to favor the former, and in 1925, definite evidence as to their influence on calcium metabolism was established by Collip, 1 and by Collip, Clark and Scott. 2 While engaged in an attempt to produce by means of partial parathyroidectomies a condition in the bones of experimental animals analogous to idiopathic osteopsathyrosis in man, it occurred to me that it would be interesting to note the effect of parathyroidectomy, partial or complete, on the healing of fractures. Morel 3 (1909-1910) working with cats, and Canal (1919) working with rats, asserted that removal of the parathyroids causes a delay in the healing of fractures.

Autoplastic and homoplastic parathyroid transplantation

Six cats were thyroparathyroidectomized and autoplastically grafted with the two external parathyroids. In four animals the glands were implanted into a pocket cut in the sternohyoid muscle; the remaining two cats were transplanted in the rectus abdominis muscle. The parathyroids were dissected free from all investing membranes, the dissection being done in a half and half mixture of warm, sterile Ringer's solution and blood serum of the animal from which the glands were taken. In some instances the parathyroids remained in the solution for fifteen minutes before implantation. Table I summarizes the principal results of the experiment.In a series of homoplastic transplantations, twenty-eight cats were used, the donor of the glands being of the same sex as the recipient, and as nearly the same age as possible. The grafts were of two types with respect to the time when made: (1) immediately following the onset of tetany symptoms; (2) simultaneous or criss-cross operations in which the parathyroids of two ca...

Autoplastic and homoplastic parathyroid transplantation.

Six cats were thyroparathyroidectomized and autoplastically grafted with the two external parathyroids. In four animals the glands were implanted into a pocket cut in the sternohyoid muscle; the remaining two cats were transplanted in the rectus abdominis muscle. The parathyroids were dissected free from all investing membranes, the dissection being done in a half and half mixture of warm, sterile Ringer's solution and blood serum of the animal from which the glands were taken. In some instances the parathyroids remained in the solution for fifteen minutes before implantation. Table I summarizes the principal results of the experiment.In a series of homoplastic transplantations, twenty-eight cats were used, the donor of the glands being of the same sex as the recipient, and as nearly the same age as possible. The grafts were of two types with respect to the time when made: (1) immediately following the onset of tetany symptoms; (2) simultaneous or criss-cross operations in which the parathyroids of two ca...

A preliminary survey of the effects of ultra violet light on normal rabbits.

With no prejudice regarding the results to be obtained we have exposed five series of normal rabbits to the quartz mercury arc lamp daily for periods of three to seven weeks and observed at autopsy the weights of certain endocrine glands in relation to the body weights of the animals. It was expected that this survey might orient us for further studies in the biophysics of ultra violet light. The survey was made possible by the cordial cooperation of Doctors Brown, Pearce, and Van Allen, who placed at our disposal unpublished figures from similar examinations on a large number of normal rabbits covering a period of two years. Many controls are required because of individual and especially seasonal variations in the gland/body weight ratio. Light colored or albino male rabbits, with ears shaved and backs clipped, in groups of eight (two controls), were exposed to the unfiltered radiations of a quartz mercury arc lamp for 30 minutes daily at a distance of one meter. This arbitrary dosage was probably too large at first and relatively ineffective during the final periods, when pigmentation had occurred. It caused a marked erythema with some desquamation, followed by moderate pigmentation. At the expiration of the chosen periods the rabbits were etherized and bled from the aorta. The following glands were weighed and examined in gross and microscopically: pineal, hypophysis, external parathyroids, thyroid, thymus, adrenals, and testicles. The weights of these glands were recorded in milligrams per kilogram net body weight after removel of the gastro-intestinal tract and its contained food and feces, and the expression of bladder urine. The changes in weight, per cent, compared with the figures for 15 to 36 normal control rabbits examined at the same season of the year are shown in the accompanying table.

THE INTERNAL SECRETION OF SANDSTROEM’S GLANDS. PARATHYROID HYPOFUNCTION AND ECLAMPSIA

In 1896, Vassale and Generali (1) demonstrated experimentally that the parathyroids, which were discovered in 1890 by Sandstroem, and which were believed to be an embryonic residue of the thyroid, are indispensable to life, the abolition of their function causing death from tetany. Afterwards Massaglia (2) completed this study. Operating on puppies, he was able to remove the thyroid without disturbing the two external parathyroids (sometimes in the dog these glands are situated at the anterior poles of the thyroid). In these experiments the animal later developed myxedema, but never developed tetany. In the litter control the removal of both the external and one of the internal parathyroids produced no morbid symptoms, and the animal remained normal. The experiment shows clearly that the thyroid and Sandstroem’s glands have different functions. The former exerts a trophic action on the metabolic changes of the body; when this function is abolished, myxedema follows. The latter exercise an antitoxic action

AGE AS A FACTOR IN THE EFFECTS WHICH FOLLOW THYROIDECTOMY AND THYROPARATHYROIDECTOMY IN THE SHEEP

1. Removal of the thyroid with the contained internal parathyroids in thirteen adult sheep and sixteen lambs from seven to eight months old, led to practically no ill effects.2. As the result of a similar operation, three lambs about two months old became typical cretins.3. The complete operation (thyro‐parathyroidectomy) in four adult sheep was followed by no symptoms during the time (three to four months) they were under observation.4. The same operation (thyro‐parathyroidectomy) in four young lambs (five to seven weeks) resulted early in acute and fatal tetany.5. Removal of the two external parathyroids from the three cretins when about one year old was followed by only slight symptoms.With regard to the effects both of thyroidectomy and of parathyroidectomy in the sheep, age is a very important factor.

The influence of experimental cretinism upon nitrogenous metabolism in the sheep

The object of the investigation was to determine whether athyroidism in sheep is associated with any striking abnormality of intermediary metabolism, such as might be revealed by the nitrogen partition of the urine. The subjects were three sheep which have already been described before this Society by Simpson. At the age of two months they had suffered the loss of the thyroid and internal parathyroid glands, and had subsequently developed into typical cretins. One year after the first operation the external parathyroids also had been removed. While the later condition was of course not that of uncomplicated athyroidism, symptoms referable to the loss of the parathyroids were but slightly marked. Tetany, in particular, was never observed. When the animals came under my care they were one and a half to two years old. To furnish a basis of comparison two normal sheep, nearly four years of age, were included in the investigation. As the most convenient way of avoiding the difficulties caused by variable appetite, etc., all five animals were starved. The urine was collected as voided. The normal animals endured fasts of five days'duration with little apparent distress or enfeeblement. Of the others two rapidly weakened, and succumbed within six days; the third was in excellent condition after seven days without food. Below is shown the ascertained distribution of nitrogen in the urine of one normal and one operated animal. The records of the others were of corresponding character. Nitrogen partition in the urine of the normal sheep is seen to follow the general mammalian type, the only point worthy of special note being the comparatively small proportion of purine nitrogen excreted as allantoin. In the urine of the thyroidectomized animal the only constituents apparently affected are ammonia and creatine.