Cranial Pole Research Articles

The surgical anatomy of the stifle joint in sheep.

To provide a detailed description of the surgical anatomy of the stifle joint in sheep. The results from analysis of cadaveric dissections (14 stifle joints) and stifle radiographs (8 sets of mediolateral and craniocaudal radiographs) are presented. Skeletally mature ewes of mixed breeds. Although the anatomy of the ovine stifle joint is similar to that of the human knee joint, a number of unique features were identified. These included the presence of the tendon of the m. extensor digitorum longus on the craniolateral aspect of the stifle joint, the absence of a cranial meniscofemoral ligament (ligament of Humphrey) in the caudal joint space, and attachment of the patellar tendon to the cranial pole of the patella (rather than to the distal pole, as in humans). The implications of these differences are discussed with reference to the suitability of the ovine stifle as a surgical model for the human knee joint.

The pig kidney as an endourologic model: anatomic contribution.

We present detailed anatomic findings on collecting system anatomy and renal morphometry in the pig and compare these findings with previous findings in humans. We studied three-dimensional polyester resin corrosion endocasts of the pelviocaliceal system obtained from 100 kidneys (50 pigs). Eighty kidneys were evaluated morphometrically, considering length, cranial pole width, caudal pole width, thickness, and weight. The pig collecting system was classified into two major groups (A and B). Group A (40%) was composed of kidneys in which the mid-zone is drained by calices dependent on the cranial or the caudal caliceal group or both. Group B (60%) kidneys have the mid-zone drained by calices independent of the polar groups. Group B includes two subtypes (B-I and B-II). The pig collecting system showed only angles smaller than 90 degrees between the caudal (lower) infundibulum and the renal pelvis. Renal morphometric measurements revealed the following means: length 11.8 cm, cranial pole width 5.64 cm, caudal pole width 5.35 cm, thickness 2.76 cm, and weight 98 g. As in human kidneys, one may group the pig collecting system into two groups. Nevertheless, in pigs, we did not find a subdivision of Group A. The incidence of collecting systems in Groups A and B and the subtypes of Group B in pigs are different from those in humans. Also different from humans, in pigs, we found only angles smaller than 90 degrees between the caudal (lower) infundibulum and the renal pelvis. Except for the length, the means of the other morphometric measurements of the pig kidney are smaller than those of humans. From an anatomic standpoint, despite the differences pointed out, we conclude that the pig kidney is a good animal model for endourologic research and training.

Androgen action during male sex differentiation includes suppression of cranial suspensory ligament development.

The cranial suspensory ligament is located on the border of the cranial (mesonephric) mesentery in adult female mammals, which runs between the cranial pole of the internal genitalia and the dorsal abdominal wall. Absence of the cranial suspensory ligament in male mammals depends upon exposure of its primordium to fetal testicular androgens and is a prerequisite for testis descent. Female rats were exposed to 5alpha-dihydrotestosterone propionate at different stages of genital development, and cranial suspensory ligament development was studied in neonatal and in adult animals. Androgens suppressed cranial suspensory ligament development when exposure started during the early stages of genital development, until day 19 postconception (pc). Androgen receptor expression was immunohistochemically detected in the cranial mesentery of both sexes from day 16 pc onwards. A decrease of androgen receptor expression in female fetuses from day 18 pc onwards coincided with the appearance of a differentiated cranial suspensory ligament, as evidenced by the expression of two cell differentiation markers: alpha-smooth muscle (alpha-SM) actin and desmin. alpha-SM actin was located on the outer border of the cranial mesentery of both sexes at day 17 pc, and expression increased only in female fetuses. On day 19 pc, desmin expression was also detectable in the a-SM actin-positive cells. Proliferation and apoptosis indices of cells in the cranial mesentery, as analysed by 5'-bromodeoxyuridine incorporation and by detection of DNA strand breaks (TUNEL method) respectively, did not show any difference between the sexes, neither on day 17 nor on day 18 pc. Since primordial cells of the cranial suspensory ligament highly express the androgen receptor during the period of gestation when androgens can suppress cranial suspensory development, altered morphogenesis of these cells may be a direct consequence of androgen action.

Rehabilitation of dogs with surgically treated cranial cruciate ligament-deficient stifles by use of electrical stimulation of muscles

SUMMARY Objective To determine effect of electrical muscle stimulation (EMS) on rate and degree of return to function of the limb and development of degenerative joint disease (DJD) after surgical creation and subsequent stabilization of the cranial cruciate ligament (CrCL)-deficient stifle. Animals 12 clinically normal adult large (19.5 to 31.5 kg) dogs. Procedure Dogs were anesthetized, and the right CrCL was severed via arthrotomy, destabilizing the stifle. After 3 weeks, the stifle was surgically stabilized. Three weeks later, 6 dogs were subjected to an EMS treatment protocol for the thigh muscles. At 5, 9, 13, and 19 weeks after stifle destabilization, treated (n = 6) and control (n = 6) dogs were evaluated for return of stifle function. Gross and histologic evaluations of the stifles were performed at 19 weeks after stifle destabilization. Results Treated dogs had significantly (P = 0.001) better lameness score than did control dogs. There was less palpable crepitation of the stifle in treated dogs (P = 0.06); treated dogs also had significantly (P = 0.01) fewer radiographic signs of bone changes. Thigh circumference was significantly (P = 0.02) larger in treated dogs.There was less gross cartilage damage (P = 0.07) in the EMS-treated dogs, but more medial meniscal damage (P = 0.058, cranial pole; P = 0.051, caudal pole). Conclusions Improved lameness scores, larger thigh circumference, and decreased radiographically apparent bony changes observed for the treated group of dogs support the hypothesis that dogs treated by EMS after surgical stabilization of the CrCL-deficient stifle had improved limb function, with less DJD, than did dogs treated with the currently accepted clinical protocol of cage rest and slow return to normal activity. However, results of force plate evaluation did not support the hypothesis. Increased meniscal damage in dogs treated by EMS may be cause for concern. (Am J Vet Res 1997;58:1473–1478)

Anatomy of medullary and peripheral autonomic neurons innervating the neonatal porcine heart

Gross and microscopic anatomical investigations were carried out in 14 piglets aged from 4 to 66 days. True Blue (7–50 μl) and Diamidino Yellow (7–50 μl) were injected individually into 2 different cardiac sites (the right atrial ganglionated plexus, the inferior vena cava, inferior atrial ganglionated plexus, the right atrium or the right ventricle). Gross anatomy: Globular superior cervical and nodose ganglia, elongated stellate ganglia, multiple small middle cervical ganglia and multiple small mediastinal ganglia along the course of cardiopulmonary nerves were identified. Microscopic anatomy: Neurons innervating specific cardiac regions or intrinsic cardiac ganglionated plexuses were distributed relatively evenly among stellate (primarily in their cranial poles) and middle cervical ganglia bilaterally, fewer labeled neurons being located in the superior cervical and mediastinal ganglia bilaterally. Parasympathetic efferent preganglionic neurons associated with either intrinsic cardiac ganglionated plexus studied were identified primarily throughout the ventrolateral region (the external formation) of the nucleus ambiguus bilaterally. Labeled neurons were also identified throughout the right and left nodose ganglia. Individual neurons did not project axons to different cardiac regions, as no double-labeled neurons were identified. No correlation between age and the numbers and locations of labeled neurons was apparent. Thus, porcine sympathetic efferent neurons which innervate individual cardiac regions, including intrinsic cardiac ganglionated plexuses, lie scattered primarily throughout the right and left mediastinal and middle cervical ganglia as well as the cranial poles of stellate ganglia at birth, apparently changing little during the first 2 months of age. Porcine cardiac parasympathetic efferent preganglionic neurons are located primarily in the external formation of the nucleus ambiguus bilaterally at birth. The numbers of afferent cardiac neurons distributed throughout the nodose ganglia bilaterally also change little during that time. It is concluded that most of the autonomic neurons which innervate the heart are in place at birth.

Targeted disruption of the estrogen receptor gene in male mice causes alteration of spermatogenesis and infertility.

The reproductive system of male mice homozygous for a mutation in the estrogen receptor (ER) gene (ER knock-out; ERKO) appears normal at the anatomical level. However, these males are infertile, indicating an essential role for ER-mediated processes in the regulation of male reproduction. Adult ERKO male mice have significantly fewer epididymal sperm than heterozygous or wild-type males. Although spermatogenesis is occurring in some seminiferous tubules of 3- to 5-month-old ERKO males, other tubules either have a dilated lumen and a disorganized seminiferous epithelium with few spermatogenic cells or lack a lumen and contain mainly Sertoli cells. There are no obvious differences in seminiferous tubules at 10 days of age between wild-type and ERKO mice, but the lumen in ERKO males is dilated in all seminiferous tubules by 20 days. However, spermatogenesis progresses and similar numbers of sperm are present in the cauda epididymis of ERKO and wild-type males until 10 weeks of age. Disruption of spermatogenesis and degeneration of the seminiferous tubules become apparent after 10 weeks in the caudal pole of the testis and progresses in a wave to the cranial pole by 6 months. However, the seminal vesicles, coagulating glands, prostate, and epididymis do not appear to be altered morphologically in ERKO mice. Serum testosterone levels are somewhat elevated, but LH and FSH levels are not significantly different from those in wild-type males. Sperm from 8- to 16-week-old mice have reduced motility and are ineffective at fertilizing eggs in vitro. In addition, ERKO males housed overnight with hormone-primed wild-type females produce significantly fewer copulatory plugs than do heterozygous or wild-type males. These results suggest that estrogen action is required for fertility in male mice and that the mutation of the ER in ERKO males leads to reduced mating frequency, low sperm numbers, and defective sperm function.

ULTRASONOGRAPHY OF ADRENAL GLANDS IN NORMAL FERRETS

The adrenal glands of 20 normal ferrets were imaged with ultrasound. Of the forty glands, only 4 (three right and one left) could not be clearly identified. Mean (±standard deviation) dimensions of the right (7.6 ± 1.8 mm length by 2.6 ± 0.4 mm width) and left (7.2 ± 1.8 mm length by 2.8 ± 0.5 mm width) glands were similar. Both adrenal glands were wider (p<0.05) sonographically in males than females. Measured length and width of the right gland positively correlated (p<0.05) with body weight. The glands had a hypoechoic outer zone and hyperechoic central region, were elongate to avoid in shape and located medial and, variably, at the level of the cranial pole of the ipsilateral kidney. This study demonstrates that normal adrenal glands can be imaged in ferrets.

Sexual differentiation of the urogenital system of the fetal and neonatal tammar wallaby, Macropus eugenii.

In male tammar wallabies, the scrotum is the first organ to become sexually differentiated, 4-5 days before birth (day 22 of gestation). This is followed by enlargement of the gubernaculum and processus vaginalis one day before birth. However the indifferent gonad does not show any signs of testicular cord formation or androgen production until later, at around the time of birth; this is more pronounced at 2 days post-partum (p.p.), when the testis takes on a characteristic rounded appearance. Primordial germ cells proliferate throughout the testis at this time, although the testis does not become significantly heavier than the ovary until around 80 days p.p.. In females, the appearance of the mammary glands is the first sign of sexual differentiation 4-5 days before birth. The indifferent gonad first shows signs of developing an ovarian cortex and medulla 7 days after birth. The migrating germ cells are confined to the cortex, and first start to enter meiosis about 25 days after birth. The Wolffian (mesonephric) ducts are patent to the urogenital sinus in fetuses at day 21 of gestation. In the female they have started to regress by 10 days p.p. and only rudiments remain by day 25 p.p.. The Müllerian (paramesonephric) ducts develop adjacent to the cranial pole of the mesonephros at about day 25 of gestation and grow caudally to meet the urogenital sinus between days 2 and 7 p.p.. The Müllerian duct of the female develops a prominent ostium abdominale by day 9 p.p., but this structure has completely regressed in males by day 13 p.p.. The testis and ovary both migrate caudally, together with the adjacent mesonephros, at about day 10 p.p.. The ovaries remain around the level of lumbar vertebra 4 after about day 7 p.p., while the testes continue to descend. The testes enter the internal inguinal ring at about day 25 p.p., about the time that prostatic buds first appear in the urogenital sinus, and are in the inguinal canal from days 25 to 36 p.p.. They enter the scrotum at around day 36 p.p., and testicular descent is complete by days 65-72 p.p.. Melanin develops in the tunica vaginalis 72 days after birth. The overall development of the urogenital system in this marsupial is similar to that of eutherians but the sequence of events differs, with some aspects of genital differentiation preceding gonadal differentiation, apparently because they are directly controlled by X-linked genes, rather than indirectly controlled by gonadal steroids.

Eine isolierte fetale Nierenzyste als ein Zeichen für ein kongenitales Neuroblastom

As a normal scan at 20 weeks of gestation a pregnant woman was referred at 36 weeks because of a cystic tumour in the fetal kidney. The cyst, 27 mm in diameter, was localised at the cranial pole of the right kidney. A fetal neuroblastoma was suspected. At the fourth day after birth adrenalectomy was performed and the histological finding confirmed the prenatal diagnosis. Two years later the child is healthy. In review of the literature we found that sonographic pattern and localisation of fetal neuroblastoma are different, but in all cases the detection was performed in the third trimester of gestation.

The ovarian-uterine vasculature in relation to unilateral endometrial growth in flying foxes (genus Pteropus, suborder Megachiroptera, order Chiroptera)

The ovarian-uterine vasculature was examined in three Australian species of flying fox (Pteropus scapulatus, P. poliocephalus and P. alecto). Vascular casts and histological sections were used to determine the relationship between the blood supply and the localized endometrial reaction, which occurs ipsilateral to the ovulating ovary. The ovarian artery coils extensively just cranial to the ovary, gives off a branch to the ovary and continues caudally as the major vessel supplying the cranial tip of the uterus, where it anastomoses with the smaller uterine artery. The coil of the ovarian artery is completely enclosed by a venous sinus that drains the cranial pole of the ovary. The ovary is heavily encapsulated, with primordial follicles restricted to the caudal pole; thus, the corpus luteum is completely internal and placed cranially, close to the coil of the ovarian artery. This arrangement would allow countercurrent or crosscurrent transfer of ovarian steroids from ovarian vein to ovarian artery and on to the cranial tip of the ipsilateral uterine horn. The steroids could thus reach high concentrations locally and generate localized endometrial growth. Cranial to the coil, the ovarian artery is enclosed in a venous sinus that derives from uterine as well as ovarian veins. This would allow countercurrent transfer of bioactive substances from uterus to ovary.

Conjoined twin piglets with duplicated cranial and caudal axes.

Twins with doubling of the cranial and caudal poles, yet having a single thorax, are rare. One set of diprosopus, dipygus porcine conjoined twins was studied. In addition to the conjoining anomaly, these twins also exhibited ambiguous internal reproductive features. The twins had two snouts, three eyes, a single thorax, and were duplicated from the umbilicus caudally. Radiography indicated a single vertebral column in the cervical region. The vertebral columns were separate caudally from this point. There was a total of six limbs--one pair of forelimbs and two pairs of hindlimbs. Many medial structures failed to develop in these twins. Medial cranial nerves V-XII were absent or displaced although apparently normal laterally. The medial palates were present but shortened, whereas the medial mandibular rami had folded back on themselves rostrally to form a midline mass between the two chins. Each twin had only one lateral kidney and one lateral testis. Medial scrotal sacs were present but devoid of a testis. There was a midline, "uterine"-like structure which crossed between the twins. However, histological analysis of this structure revealed it to be dysplastic testicular tissue. The relationship between the abnormal reproductive features in these twins and the conjoining is unclear. The anatomy of these twins, in addition to the literature reviewed, illustrates the internal anatomical heterogeneity of grossly similar conjoined twins. A review of the literature also suggests that conjoined twinning may be more common in swine than was previously suspected.

The influence of variations of the coracoacromial arch on the development of rotator cuff tears.

In order to define the geometry of the coracoacromial arch in both its bony and soft parts and to bring it into relationship with rotator cuff tears, 54 cadaver shoulders (from subjects aged 47-90 years) were dissected and X-rayed (anteroposterior projection and supraspinatus outlet view). Partial rotator cuff tears were assessed additionally by transillumination and polarized microscopy. After transfixation of the coracoacromial arch with a polyurethane mould, sections were made along the coracoacromial ligament. The morphology of the acromion was described following the classification of Bigliani et al. [5]. Amongst other parameters, measurements were taken between the long axis of the scapula, the spina, and the acromion. In 19 of 22 cases, a traction osteophyte was associated with rotator cuff tears. In incomplete tears, spurs were completely encased within the ligament and did not impair the subacromial space. The number of rotator cuff tears was significantly increased in shoulders with "curved" acromia, flat acromial slope, and increased angle between the scapular plane and the spina (intact, mean 58 degrees; tears, mean 47 degrees). The morphology of the subacromial space was secondarily determined by this angle. In contrast to Bigliani et al. we were unable to find a "hooked" acromion. These results indicate that the combination of a flat and curved acromion or a position of the acromioclavicular joint above the cranial pole of the glenoid must be regarded as considerable risks for the development of rotator cuff tears. The concept of anterior acromioplasty is supported by our results.

Nodular Dermatofibrosis and Renal Cystadenomas in a Golden Retriever

Abstract— The clinical and histologic features of a 2‐year‐old intact male golden retriever with nodular dermatofibrosis and renal cystadenomas are described. The skin lesions failed to respond to antibiotic and glucocorticoid therapy. Abdominal ultrasound revealed a wedge‐shaped area of hyperechoic mottled echogenicity at the cranial pole of the left kidney and a small right kidney. Euthanasia was performed thirty‐six months following initial presentation, owing to progressive enlargement of the dermal and subcutaneous nodules and gross deformity of the left hind limb secondary to fibrous tissue deposition and lymphatic obstruction. Necropsy confirmed the presence of bilateral renal cystic hyperplasia and multifocal renal cystadenomas. This is the first confirmed report of nodular dermatofibrosis and renal cystadenomas in a breed other than the German shepherd dog.

Hyperadrenocorticism associated with adrenocortical tumor or nodular hyperplasia of the adrenal gland in ferrets: 50 cases (1987-1991)

Summary Adrenocortical adenoma, nodular hyperplasia, or carcinoma was diagnosed in 50 ferrets. Thirty-five (70%) ferrets were female and 15 (30%) were male. The mean age at which clinical signs were first noticed was 3.4 years (range, 1 to 7 years). Clinical signs included large vulva (n = 31; 89% of females), alopecia (n = 43; 86%), pruritus (n = 20; 40%), and increased consumption of water and increased urine output (n = 4; 8%). A mass was palpated at the cranial pole of the kidney during physical examination of 17 (34%) ferrets. Ultrasonography, performed on 39 of 50 ferrets, revealed a unilateral adrenal gland mass in 19 (49%). Four ferrets were anemic, and 2 ferrets were thrombocytopenic. Baseline plasma concentrations of cortisol and corticosterone were within or below the reference range in all 17 ferrets tested, whereas baseline plasma estradiol concentrations were high in 4 of the 11 ferrets (36%) tested. After adrenocorticotropic hormone (acth) administration, only 1 ferret had a slightly exaggerated response on the basis of plasma cortisol concentrations, and all 17 had normal responses on the basis of plasma corticosterone concentrations. There was little or no increase in plasma estradiol concentrations after acth administration. Of the 50 ferrets, 39 were treated by adrenalectomy. Unilateral adrenalectomy was performed in 34 ferrets in which 1 adrenal gland was large, whereas subtotal bilateral adrenalectomy was performed in 5 ferrets with bilateral adrenal disease. Five ferrets died in the immediate postoperative period, and follow-up information was available for the remaining 34, 1 to 34 months after surgery. A decrease in vulvar size was generally noticed by 2 days after surgery, and complete hair regrowth was noticed by 2 months. Because clinical signs resolved after adrenalectomy, it was likely that the adrenocortical tumors and nodular hyperplasias of the adrenal gland were hyperfunctional. However, these ferrets did not have excessively high circulating concentrations of cortisol. At present, we recommended that diagnosis of adrenocortical disease in ferrets be made on the basis of characteristic clinical signs, results of abdominal ultrasonography, and finding large adrenal glands during surgery. Results of acth stimulation tests, with determination of plasma cortisol or corticosterone concentrations, were of no value in the diagnosis.

RENAL SONOGRAPHIC MEASUREMENTS IN THE DOG PRECEDING AND FOLLOWING UNILATERAL NEPHRECTOMY

The purpose of this study was to establish sonographic baseline values for normal kidneys initu and to document sonographic changes following unilateral nephrectomy. Normal canine renal measurements were determined sonographically prior to and following unilateral nephrectomy. These included: cortical thickness (cranial, caudal, dorsal, ventral, lateral and medial), medullary measurements (cranial and caudal) and measurements of the renal silhouette (length, height and width). The latter group of measurements was obtained to determine renal volume. Normal parameters were obtained from sixteen healthy dogs prior to nephrectomy; the unilateral nephrectomy group was comprised of eight of these animals, the remaining eight dogs were part of an allo‐transplant study.1 The mean sonographic value for the length of the kidney was 60.3 mm ± 6.4 (n = 26) while the widths and heights were 34.7 ± 3.8 (n = 27) and 27.8 mm ± 3.3 (n = 26) respectively. Renal cortical measurements were found to be smallest dorsally and ventrally on sagittal and transverse sonograms. The largest volumes were the cranial pole on sagittal scans and the lateral pole on the transverse scans. Pearson correlation coefficient for volume resulted in r values of 0.88, 0.78 and 0.72 for length, height and width (n = 25, dif = 24) respectively.

ULTRASONOGRAPHIC EVALUATION OF THE PARATHYROID GLANDS IN HYPERCALCEMIC DOGS

Two hyperplastic parathyroid glands and three solitary parathyroid adenomas were identified using high‐resolution ultrasonography in five adult dogs with persistent hypercalcemia. Ultrasonographic features of parathyroid adenomas included visualization of a round or oval, 5 mm or larger, hypoechoic mass in the cranial pole of one thyroid lobe. Each mass had well‐defined margins between the thyroid gland and parathyroid adenoma, reduced echogenicity of the adenoma compared to surrounding thyroid parenchyma, and distal enhancement. Ultrasonographic features of the hyperplastic parathyroid glands included hypoechogenicity, compared to surrounding thyroid parenchyma, and a size of approximately 2 mm. Hyperplastic parathyroids were well marginated in one dog and poorly marginated in another dog.

Oxytocin modulation of intrathoracic sympathetic ganglionic neurons regulating the canine heart

Substance P and vasoactive intestinal peptide are known to activate intrathoracic sympathetic neurons which regulate the heart. In the present series of experiments, when 1 I.U. of oxytocin in 0.1 cc of normal saline was administered into the cranial poles of stellate or the middle of middle cervical ganglia cardiac rate and force were augmented. The locations of ganglionic loci which, when injected, resulted in cardiac changes varied between animals. Twenty active sites were identified in the 12 dogs investigated. When the vehicle (0.1 cc of normal saline) was injected into these active sites minimal cardiac responses were induced in one instance. When 1 or 2 I.U. of oxytocin was administered into the superior vena cave of seven animals slight systemic hypotension occurred in two of these animals. Cardiac responses were induced when oxytocin was reinjected into active intrathoracic ganglionic sites after whole body administration of hexamethonium (10 mg/kg IV), but not after local administration of timolol into the ganglia. Thus, it appears that oxytocin can activate intrathoracic ganglionic neurons involved in efferent sympathetic cardiac regulation. That such responses persist in the presence of nicotinic blockade, but not following beta-adrenergic blockade of ganglionic neurons, indicates that oxytocin modifies beta-adrenergic and not nicotinic receptors on neurons in these ganglia.

Testicular migration, spermatogenesis, temperature regulation and environment of the sheath-tail bat, Taphozous georgianus.

The testes of the common sheath-tail bat of tropical Australia undergo a seasonal migration between the abdomen and the scrotal pouches, while each cauda epididymidis is permanently maintained in the scrotal pouch. Straps of smooth muscle attach to both the cranial and caudal poles of the testes, and these extend cranially to the diaphragm and caudally to the cauda epididymidis. The testicular arteries are not coiled. Among the environmental factors investigated, maximum temperature correlated most significantly with testicular descent, and the number of spermatogonia per bat also correlated most significantly with maximum temperature. Body temperature of a captive bat ranged from 25 to 38 degrees C and this was closely related to body weight and ambient temperature. It seems likely that the scrotal pouch provides a temperature slightly below that of the body and so facilitates sperm storage in the permanently scrotal cauda epididymidis. Migration of the testes probably serves to ameliorate the seasonal temperature fluctuations to which they are exposed while the relatively high correlation between maximum environment temperature and spermatogonial numbers suggests that temperature may be a proximate influence on reproduction in the sheath-tail bat.

Vaginal sonography of intact pregnancy in the first trimester

The experiences in vaginal sonography in early pregnancy are reported and the first results concerning the dimensions of various structures in relation to gestational age are given. Intra-uterine structures can be identified and evaluated from a measured minimum diameter of 2-3 mm. Visualization of the chorionic cavity which proves an intra-uterine pregnancy, is possible with 4 complete weeks p.m. With 10 weeks p.m., it reaches a mean diameter of nearly 50 mm. The yolk sac which normally measures 4-5 mm and excludes a blighted ovum, is reliably seen from 5 to 10 weeks p.m. The embryo and its cardiac action which proves viability of the gestation, is recognized with 6 weeks p.m. With 10 weeks p.m., the crown-rump-length measures approx. 40 mm. Thus with vaginal sonography, the mentioned important parameters of early gestation are visible 1-2 weeks earlier than with abdominal ultrasound examination. Furthermore, other structures like amnion, umbilical cord, cranial pole of the embryo etc., can be identified earlier and in more detail. The corpus luteum is frequently recognized in the ovary as an echo-free structure with a more echo-dense border. If a non-viable early pregnancy is suspected, long hospitalization and expensive hormonal investigations are avoided by the early demonstration of a viable intra-uterine pregnancy.

Intratesticular injection as a method to assess the potential toxicity of various agents and to study mechanisms of normal spermatogenesis.

To better understand, to optimize, and to validate the technique of intratesticular (i.t.) injection, several parameters related to i.t. injection were examined. Volumes exceeding 50 microliters could be injected i.t.; however, testes frequently became excessively turgid and backflow of injected fluids occurred. Thus, a volume of 50 microliters or less was deemed optimal for injection. To determine the rate of distribution of substances throughout the testis, trypan blue was injected i.t. near the caudal pole of the testis, and the movement of dye was monitored. Within 2 min, the dye had spread approximately 1 cm from the site of injection, and in 5 min it had spread twice that distance. In 2 h, the dye had become distributed throughout the testis except at its extreme cranial pole. Seminiferous tubules did not take up dye, indicating that the spread of dye was via peritubular lymphatics. Seminiferous tubule histology appeared virtually unaffected by i.t. injection, even at regions adjacent to the site of injection, when a sterile 26-gauge or smaller bore needle was utilized. To determine disappearance from the testis, radiolabeled inulin was injected i.t. Half time for absorption was achieved at 1.75 h. Potential vehicles were explored in which compounds with a variety of physical properties could be injected. Gum tragacanth, normal saline, ethylene glycol, dimethyl sulfoxide (DMSO) mixed 1:1 with normal saline, sesame oil, and propylene glycol were found to be suitable injection vehicles, whereas ethanol, dissolved in normal saline in concentrations as low as 0.5% was found unsuitable. To assess vehicle efficiency, various vehicles were utilized with a known testicular toxin (taxol) and injected into one testis, and the histology was compared with the contralateral testis injected with vehicle alone. All vehicles, found suitable above, allowed dispersion of taxol to influence areas distant from the site of injection. Intratesticular injection assesses the potential of agents to directly affect the testis, and systemic metabolism is avoided. Their rapid spread throughout the lymphatics of the testes allows seminiferous tubules to be exposed to agents in innocuous vehicles more rapidly and in higher concentration than is often possible when using systemic injections.