Effect of timing of insemination, numbers of spermatozoa and extender components on the pregnancy rate in mares inseminated with frozen stallion semen. Fertilization rate was highest in mares inseminated with frozen semen within 12 hr of ovulation. Foaling rate was improved (P less than 0-05) by increasing the number of motile spermatozoa inseminated from 40 X 10(6) to 80 X 10(6) but was not further improved by increasing the number to 160 X 10(6) or by increasing the frequency of insemination from once to twice daily. The fertilizing capacity of spermatozoa frozen in one of the hydrogen ion extenders studied was dependent upon relative osmotic pressure and method of freezing (ampoules or pellets). Adjusting glycerol concentration from 7% to 2%, addition of glycerol 15 min before freezing and freezing 2 hr after extension all enhanced the fertilizing capacity of spermatozoa. Pregnancy rate per mare service period was higher (P less than 0-01) for mares inseminated with unextended semen (75%) than for extended semen containing no glycerol (50%) or extended semen containing 7% glycerol (35%). Although wide variability in the fertilizing capacity of spermatozoa from individual stallions was observed when semen was extended or extended and frozen, pregnancy rate was depressed in all stallions. It was concluded, therefore, that hydrogen ion extenders depress fertilizing capacity of stallion spermatozoa immediately after extension and show little promise as semen extenders for short- or long-term storage of stallion semen.


Ejaculatory disorders of the stallion.

Ejaculatory disorders of the stallion. Ejaculatory disorders of the stallion seem to occur more frequently than hitherto accepted. The condition is manifested differently in individual stallions from normal copulation without ejaculation to an abnormal pattern of copulation without or with occasional ejaculation. The condition is probably caused by a functional disturbance of the nervous mechanism which controls the ejaculatory process, and may be caused by environmental or other factors. Eleven cases of ejaculatory disorders in normal healthy stallions were investigated and three of these animals recovered after simple correction of environmental factors, including the number of mares served. Of the eight stallions which did not respond to environmental changes, one recovered after treatment with pilocarpine and one after treatment iwth ephedrine. Possible causes of failure of the nervous regulation of the reproductive tract are discussed.


Abnormalities of mating behaviour in domestic stallions. Experimental and clinical observations were made to treat abnormal sexual behaviour. The most common cause of abnormality was mismanagement of the animal; over-use and rough treatment at service and too-frequent ejaculation during winter had a detrimental effect on the behaviour of young stallions. Pain due to injury incurred at copulation or when associated with mounting attempts was also a common cause of impotence. Most impotent stallions responded well to re-training and recovery can be achieved without pharmacological treatment in most cases.


Reproduction in feral horses.

Reproduction in feral horses. A behavioural study of feral horses was conducted on the Pryor Mountain Wild Horse Range in the western United States. All 270 horses on the Range were identified individually. The sex ratio was nearly balanced. Foal to adult female ratio was 43-2:100. Morality was concentrated among foals and old horses. Horses were organized as forty-four harem groups each with a dominant stallion, one to two immature stallions, one to three immature mares, one to three adult mares and their yearling and foal offspring, and 23 bachelor groups of one to eight stallions. Harem groups were quite stable year-round because of dominance and leadership by the stallions and group fidelity by mares and their offsring. Most changes occurred during the breeding season and involved immature females. Defeat of dominant stallions was infrequent. Immature males were tolerated because of their submissive behaviour. Bachelor stallion groups were inherently unstable. Mares came into heat after foaling in May/June, and were mated by harem stallions only.


Immature germ cells in the semen of thoroughbred stallions. Small but significant numbers of primary and secondary spermatocytes and spermatids have been observed in the semen of some Thoroughbred stallions. Extensive histological examination of the testes of affected animals has not been undertaken but in one young stallion which died as the result of a leg injury, the premature dehiscence of these cells seemed to be related to segmental defects within the seminiferous tubules. The causes of lesions leading to premature shedding of germ cells are discussed.


Recent observations concerning Klebsiella infections in stallions. A high incidence of Klebsiella contamination in German 'Warmblut' and Thoroughbred stallions is reported. The organism was recovered from the nostrils, prepuce, pre-ejacultory secretion and, in some cases, on the body surface, in the faeces and on the ground of the covering (mating) yard. Fertility was not affected. However, differences of virulence were observed and Type 5 proved to be the most pathogenic.


Diagnosis and treatment of haemospermia in the stallion. Haemospermia caused infertility in the stallion and frequently results from a urethritis in the area of the ejaculatory ducts. Urethroscopic examination, urethrography, bacterial and viral cultures, biopsy, surgery of the urethra and histocytological examination should be used for diagnosis and it is essential that the exact cause and location of the haemorrhage be known before treatment is initiated. Optimal treatment includes sexual rest and appropriate antibiotics used systemically in conjunction with local medication of the urethra. Cauterization of the urethra with silver nitrate solution should be avoided.


The oestrous cycle of the mare.

The oestrous cycle of the mare. In eleven non-pregnant mares examined for 2 years, oestrous cycle length was 20-6 days (range 13 to 34) excluding any anoestrous periods. The duration of oestrus was 5-7 days (range 1 to 24); from February to May it was 7-6 days (range 2 to 24) and from May to November 4-8 days (range 1 to 10). The majority of ovulations occurred between 16.00 and 08.00 hours and 78% of the mares ovulated within 48 hr of the end of oestrus. Mean follicular diameter was 45 mm on the day of ovulation and there was a 25-5% incidence of multiple ovulations. It was uncommon for oestrus to occur without ovulation, whereas ovulation without oestrus occurred in 6/11 mares, including one mare which ovulated without oestrus on 32/34 occasions. The CL was palpable after ovulation for 8-9 days (range 1 to 18). Dioestrus averaged 15-4 days (range 6 to 25). Ovulations during dioestrus, unaccompanied by signs of oestrus, occurred in 10/11 mares but cycle length was not affected. A syndrome of spontaneous prolongation of the CL, accompanied by follicular activity, without any signs of oestrus for periods of 2 to 3 months was observed in six of the mares.


A review of the influence of nutrition upon the oestrous cycle and early pregnancy in the mare. Attention is drawn to the beneficial effect of improved nutrition during winter and early spring on the ovarian activity of mares. Furthermore, the necessity of an adequate plane of nutrition during early pregnancy to prevent embryonic resorption is stressed.


Relationship between the morphology of and progesterone production by the corpus luteum of the mare. The histology of the growing, secreting and regressing CL of thirty-five cycling and early pregnant mares with known breeding histories was studied by light microscopy. Thecal cells are best developed a few days before ovulation. They regress very quickly and within 24 hr after ovulation all remaining thecal cells are in an advanced stage of degeneration. Hypertrophy and luteinization of the granulosa cells commences 10 hr after ovulation and maximum size (37-5 mum) is reached later. The luteal tissue enlarges mainly through hypertrophy of the lutein cells. Two types of lutein cells are found in the CL, a large light-staining cell and a small dark-staining cell. Degeneration of the lutein cells in the non-pregnant mare commences on Day 12 after ovulation and in the pregnant mare on Day 38 after ovulation. The primary CL of pregnancy regresses after the secondary CL are formed. The progesterone concentration in the peripheral plasma is closely correlated with the morphological changes in the CL.


Relationship between luteal function and metabolic clearance and production rates of progesterone in the mare. The functional activity of the equine CL was measured by its ability to convert [4-14C]3beta-hydroxy-5-en-20-one to [4-14C]pregn-4-en-3,20-dione. The capacity of homogenates of CL of different ages followed the temporal pattern of plasma progestagen concentrations. In ten mares which ovulated twice at intervals of 0 to 9 days in the same cycle, the conversion capacity of the CL from the second ovulation was similar to that from the first ovulation. After adjusting for age, the CL from the first of two ovulations had a similar conversion capacity as that resulting from a single ovulation. Plasma metabolic clearance rates of progesterone were similar on the 8th day after ovulation in mares having one and two ovulations. Progesterone production rates were also similar in mares with one and two ovulations. A two-component disappearance curve was observed following cessation of the [3H]progesterone infusion in mares that ovulated once or twice in the same cycle.


Effect of exogenous progesterone on its endogenous levels: biological half-life of progesterone and lack of progesterone binding in mares. The disappearance rate of progesterone from blood plasma of an ovariectomized mare was rapid and occurred in three phases. The half-life of the first component was 2-5 min and that of the second was 20 min; the half-life of the much slower third component was not measured. Progesterone, administered to ovariectomized and deeply anoestrous mares at the rate of 150 or 300 mg/day, maintained maximal peripheral levels of 6 to 8 ng/ml. Physiological levels were reached in 21 days using a dose of 150 mg and in 11 days with 300 mg daily. After withdrawal, circulating levels dropped rapidly. Blood plasma of mares appears to lack progesterone-specific binding proteins. It is concluded that the problem of habitual abortion and its treatment in mares need re-evaluation.


The cycle of oestrus, ovulation and plasma levels of hormones in the mare. The duration of the oestrous cycle and day of ovulation were recorded in six mares which were used for concurrent assay of plasma levels of sex steroids and pituitary LH concentration. Peak of progesterone were reached during dioestrus and those of oestradiol and androstenedione occurred 2 days before ovulation and were in decline on the day of ovulation. Plasma oestrone remained constant (between 9 and 12 pg/ml) throughout the cycle. Plasma LH rose to a maximum near to the time of ovulation, and thereafter decreased gradually until mid-dioestrus. The pattern of secretion is compared with that reported in other domesticated animals.


The evaluation of stallion semen in aspects of fertility control and its use for artificial insemination. Choice of the best methods for semen examination is dictated by the purpose of the examination, whether it be to assess the fertility of an individual stallion or to evaluate individual semen samples for routine purposes. In the author's experience of examining stallion semen, emphasis should be placed upon morphological examination, sperm cinematography and survival tests in vitro. Special problems concerning examination of frozen semen are discussed and the ultrastructure of spermatozoa frozen in the presence and absence of glycerol is described.


Serum concentrations of FSH, LH and progesterone during the oestrous cycle and early pregnancy in the mare. Heterologous radioimmunoassays were developed for equine FSH and LH. Serum concentrations were measured in twenty-three mares throughout the oestrous cycle and early pregnancy. FSH concentrations were raised fivefold by 'surges' rather than 'spiked', occurring at 10- to 11-day intervals during the oestrous cycle and early pregnancy. The late oestrous/early dioestrous surge of FSH appeared to initiate development of up to twenty follicles. The mid-dioestrous surge may be important for the further development of follicles destined to ovulate 10 to 13 days later. Levels of LH were increasing by the onset of oestrus and reached their maximum 1 to 2 days after ovulation. This rise in LH may stimuate maturation of the follicle throughout oestrus. An inverse relationship between progesterone and LH levels occurred, suggesting a negative feedback, but there was no such relationship between FSH and progesterone concentrations.


Levels of LH, prolactin and oestrogens in the serum of post-partum mares. The levels of LH, prolactin and oestrogen were measured by radioimmunoassay in serum obtained from six mares during the post-partum period, and LH was also assayed in blood samples collected at 6-hr intervals from four normal cyclic mares during oestrus and at daily intervals during dioestrus. The concentrations of oestrogen and LH suggested that the mares were having ovulatory cycles during the post-partum period irrespective of behavioural oestrus, and the levels of prolactin seemed to rise in association with probable ovulatory LH peaks. In these mares levels of LH had increased significantly (P less than 0-05) by Day 4 of oestrus and reached a peak (140 +/- 48 ng/ml) about 1 day before the end of oestrus. They then declined rapidly and remained at basal levels (10 to 20 ng/ml) during dioestrus.


Plasma LH levels in the mare during the oestrous cycle. Plasma levels of LH were determined by heterologous radioimmunoassay utilizing highly purified equine LH as standard. Samples were taken regularly from eleven mares for twenty-six oestrous cycles over a period of 10 weeks. The mean cycle length was 20-5 +/- 3-1 (S.D.) days, and ovulation occurred on average 4-3 +/- 1-6 (S.D.) days from the time heat was first detected. Levels of LH were persistently low from Days 5 to 16 of the cycle (ovulation = Day 0). They then increased slowly over a number of days and continued to rise beyond the levels observed at any time during the immediate preovulatory period or the day of ovulation. A significant decrease from peak levels was not observed until the 3rd day after ovaulation, from which time levels continued to decline toward dioestrous values by an apparent first-order decay process with a half-life of 1-8 days. The pattern of plasma LH in the mare differs from that reported for other species and it is suggested that persistance of high concentrations of LH results from a long half-life of the endogenous LH. This in turn may be responsible for the relatively large number of second ovulations detected in many oestrous cycles.


Urinary oestrogen and plasma progesterone levels in non-pregnant mares. Eight mares were observed clinically for 14 months to detect oestrus and ovarian activity, and assays of urinary oestrogens and plasma progesterone were performed. Cyclical ovarian activity occurred during 60% of the experimental period. Persistent luteal activity was found over 20% of the period and for the rest of the time activity was absent. Cyclical activity was characterized by the alternation of periods of low and high progesterone levels corresponding to the follicular and luteal phases of the ovarian cycle. During the follicular phase, urinary oestrogen levels increased to a maximum of 463 +/- 296 ng/ml 2 days before ovulation. The duration of the interval from complete luteolysis to ovulation (6-3 +/- 2-7 days) was correlated with oestrone peak values (r = 0-44) and with oestrone levels at the beginning of the low progesterone phase (r = -0-36). High oestrogen levels were recorded during persistent luteal activity which occurred more frequently in summer. Ovarian inactivity was more frequent in winter and was characterized by very low progesterone and low oestrogen (less than 50 ng/ml urine) levels. Some individual and seasonal effects were studied.


Oestrogen excretion in mares in relation to various reproductive states. The rate of urinary oestrogen excretion was studied in four ovariectomized mares. In two animals ovariectomized when urinary oestrogen concentration was high, levels fell to a minimun within 48 hr. Intramuscular injection of oestradiol-17beta produced maximum urinary oestrogen levels within 3 to 6 hr and a return to minimum detectable levels within 24 hr. The major urinary oestrogen in mares was oestrone. In nine maiden mares studied between September and June, the cycle, the durations of dioestrus and oestrus, and the time of ovulation were similar in autumn (September to December) and spring (January to June). All nine mares had periods of anoestrus and 'shallow' and 'deep' forms of this condition were observed. In all cyclic mares, urinary oestrogen excretion showed a gradual rise from dioestrous levels beginning 6 to 7 days before ovulation. A rapid and highly significant (P less than 0-001) fall in oestrogen excretion occurred on the day of ovulation and the day after. Maximum urinary oestrogen levels were twice as high in spring than in autumn cycles.


Influence of intrauterine saline infusion upon the oestrous cycle of the mare. The effect of intrauterine saline on reproductive function was studied by infusion of mares in anoestrus, dioestrus, oestrus and prolonged dioestrus. Anoestrous mares were unaffected except near the beginning and end of the breeding season when anovulatory heats were induced. Dioestrous mares infused between Days 5 and 9 returned to heat an average of 3-8 days earlier than expected, and infusions during dioestrus were followed by ovulatory heats of normal fertility. Three mares in prolonged dioestrus showed ovulatory heats within 3 to 9 days of infusion. Infusions during oestrus had no appreciable effect. Repeated infusions were clinically harmless but post-infusion bacteriological swabs from the uterus were positive. In two cases studied, infusion was followed by a fall in peripheral plasma progestagen concentrations. Evidence was obtained that vaginal and cervical dilatation and oxytocin were not involved in the mechanisms and it is postulated that the luteolytic effect of intrauterine saline is mediated by prostaglandin.


The influence of intrauterine saline infusion on luteal function and cyclical activity in the mare. Intrauterine saline infusion in the dioestrous mare shortened the ovulatory interval by inducing premature luteolysis. Plasma progestagen levels began to decrease approximately 1 day after the infusion and had declined to less than 1-0 ng/ml in 4 days. The CL, including others formed from ovulations during dioestrus, must be 4 to 5 days old before intrauterine saline will induce luteolysis. Of 10 mares infused on Day 4 or 5 after ovulation, only six had a shortened ovulatory interval. Of 10 mares infused on Day 6 or 7 after ovulation, seven had a shortened ovulatory interval and three failed to respond due to the occurrence of a dioestrous ovulation near the time of infusion. In those mares which responded to treatment, the interval from saline infusion to the beginning of oestrus and to ovulation was 5 to 6 days and 9 to 10 days, respectively.


Effects of artificial light on the oestrous cycle of the mare. Two groups, each of seven pony mares, were maintained from 17 October to 15 February (120 days) in the University Biotron where temperature and daily photoperiod were regulated to simulate normal conditions for that period (control group) or those normally applicable from 1 March to 1 July (treated group). Follicular growth, ovulation rate and oestrous behaviour were determined daily by rectal palpation, and by teasing with a stallion. By Day 69 of treatment, all ovarian end-points (number of follicles greater than 10 mm, number of follicles greater than 20 mm, average follicle diameter and diameter of the largest follicle) were significantly greater in treated than control mares. Oestrous behaviour was evident in all the mares in the treated group, but was not recorded in any of the control group mares; two of the treated mares ovulated. After removal from the environmental control chambers, the experimental and control mares first ovulated on an average of 147 days and 227-6 days, respectively, after the beginning of the project. Mares in both groups cycled regularly after the first ovulation and were in anoestrus again at about the same time in the following winter.


The use of prostaglandin F2alpha-tham salt in mares in clinical anoestrus. Seventy-three Standardbred and Thoroughbred mares in clinical anoestrus during the breeding season were treated with PGF2alpha. The mares were divided into four categories; foaling, barren, maiden and unknown. The response was consistent in all groups. Mares at Days 2 to 4 of dioestrus showed no decrease in plasma progesterone levels, and those at Days 6 to 8 showed a return of progesterone to baseline levels (less than 1 ng/ml) in 24 to 48 hr after treatment. Plasma progesterone levels returned to basal levels in 24 to 48 hr in 93% of mares; progesterone levels had not changed by 96 hr in 7% of the treated mares. Behavioural oestrus was detected in 71% of treated mares an average of 4-4 days after treatment, and ovulation occurred in 86% at an average of 8-9 days. Pregnancy occurred in 55-5% of the PGF2alpha-treated mares after an average of 1-7 services during the induced oestrus.


Oestrus, ovulation and plasma hormones after prostaglandin F2alpha in mares. The luteolytic effect of PGF2alpha, administered by intrauterine infusion or subcutaneous injection during early dioestrus, was observed in mares of mixed breeds. An infusion of 10 mg on Days 7 to 9 after ovulation caused a sharp fall in plasma progesterone levels and induced oestrus and ovulation. Oestrus was significantly longer than in the natural cycle but the time of ovulation in relation to the end of oestrus was normal. The time of return to oestrus following luteolysis was not dependent on the amount of PGF2alpha within the range of doses given. Luteolysis could be induced as early as Day 5 following natural ovulation.


Effects of prostaglandin F2alpha on the oestrous cycle and pregnancy in mares. Several experiments indicated that prostaglandin F2alpha (PGF2alpha) has luteolytic and abortifacient properties in mares. A single subcutaneous injection of 1-25 mg PGF2alpha on Day 6 of dioestrus was as effective as 10 mg PGF2alpha in inducing luteolysis. Oestrus and ovulation appeared to be synchronized when a single injection of 1-25 mg PGF2alpha was given on Days 7, 10 or 13 after ovulation but not on Days 1 or 4 after ovulation or on Day 2 of oestrus. Intramuscular administration was as effective as subcutaneous administration and 1-25 mg PGF2alpha was the minimal effective systemic dose to induce luteolysis. Administration of PGF2alpha into the uterus or directly into the CL did not improve the luteolytic efficacy of the intramuscular injection of PGF2alpha. All thirteen mares aborted following injections of 2-5 mg PGF2alpha at 12-hr intervals; an average of 3-7 injections were given before abortion occurred.


The use of prostaglandin F2alpha in controlling the oestrous cycle of the mare and steroid changes in the peripheral blood. Prostaglandin F2alpha (PGF2alpha), administered by untrauterine infusion and intramuscular injection, was used to induce oestrus and ovulation in non-cyclic mares. A satisfactory response rate (80% or more) was obtained and the dose (2-5--7-5 mg) and the time taken for ovulation to occur (up to 9 days) was the same irrespective of the route of administration. Only about one-half of the mares conceived to mating at the induced oestrus but the low conception rate could be attributed to the infertile condition of the mares. Plasma progesterone remained at basal levels after PGF2alpha and oestrogen levels were inconsistent. The use of PGF2alpha in the treatment of severe endometritis was successful in one mare.


Synchronization of oestrus in mares with a prostaglandin analogue and HCG. Following an initial observation period of 13 days when plasma progesterone levels were determined, synchronization of oestrus and ovulation was investigated in thirty-three mares treated with a prostaglandin analogue ('Equimate') and HCG. Two courses of treatment were given 8 days apart and each consisted of a single intramuscular injection of Equimate (250 mug) followed 6 days later by an intramuscular injection of HCG (2500 i.u.). The first course was designed to remove all luteal tissue and to induce ovulation of any follicles that developed in response to the withdrawal of progesterone. The second course had the effect of synchronizing oestrus and ovulation following luteolysis of the induced CL in all the mares. A high proportion of treated mares responded by ovulation within 24 and 72 hr after the second HCG injection and provided fertility was not disturbed, the prognosis for a high success rate by the double treatment was good. The plasma progesterone level is a reliable criterion of ovulation and would replace the need for the clinical procedures normally employed to determine the onset of oestrus and follicle rupture.


The effect of rectal palpation on the fertility of cyclic mares. The effect of rectal palpation of fertility of non-lactating, normal cyclic mares was studied over 3 years. During the first year (1971), the conception rates in mares after daily paplaption during oestrus only, and during oestrus and the first 50 days of pregnancy, were not significantly lower (P greater than 0-05) than the conception rates recorded in mares not palpated. No abortions could be attributed to palpation. Oestrus lasted longer (P less than 0-05) in non-palpated than palpated mares. During the second year (1972), first-cycle pregnancy rates in two groups of mares palpated daily during oestrus were lower (P less than 0-05) than those of mares not palpated. Daily palpation and insemination on the palpator's recommendation resulted in fewer (P less than 0-05) inseminations per cycle than in mares inseminated every other day of oestrus. During the third year (1973), the difference of first-cycle conception rates between mares palpated on alternate days of oestrus and those not palpated was not significant. Throughout the three years of the study, first-cycle conception rates following insemination with undiluted semen were higher (P less than 0-025) in non-palpated mares than in palpated mares (45-7 versus 79-2%).


Effects of progesterone on reproductive function in mares after parturition. The injection of 100 mg of progesterone/day from Days 5 to 14 after foaling blocked or delayed oestrus and ovulation in 6/9 mares; the remainder ovulated during treatment without showing oestrus. Urinary oestrogen concentrations in these mares were highest between Days 9 and 15 after foaling but the peak levels were only about half those seen in untreated mares during the post-partum oestrus and ovulation. The injection of 200 mg progesterone/day blocked oestrus and ovulation in two mares but did not depress oestrogen excretion maxima any further. Follicles prevented from developing beyond a cricital stage lost their ability to ovulate after progesterone withdrawal. No significant histological differences were found in endometrial biopsies taken from progesterone-treated and control mares on Days 5, 10 and 15 after foaling. Injection of 100 mg progesterone between Days 1 and 10 after foaling delayed oestrus and ovulation in all six mares. Conception occurred in 8/12 progesterone-treated mares as the result of mating at oestrous periods which were delayed until Days 15 to 28 after foaling.


The effect of HCG on duration of oestrus, ovulation time and fertility in mares. Two experiments were conducted to determine the effects of HCG on duration of oestrus, dioestrus, the length of the oestrous cycle, the time of ovulation and fertility in non-lactating mares. In the first experiment, the injection of HCG was repeated for three successive cycles. Mares injected with 2000 i.u. HCG on Day 2 of oestrus during their first cycle had a shorter oestrus and ovulated sooner than untreated control mares, but in the third cycle, treated mares had a longer oestrus and ovulated longer after the onset of oestrus than controls. In the second experiment, one intramuscular injection of 3300 i.u. HCG was given 24 hr before the first insemination in the first cycle. Oestrus was shortened by 3-1 days, but there was no difference in pregnancy rate between treated and control mares (61-1 versus 63-9%). During the two cycles following injection, the conception rate in the treated mares was higher. The number of inseminations/cycle to effect fertility was significantly less over three cycles in the treated mares.


Some clinical observations on the effect of an implant of oestradiol benzoate in brood mares. The clinical effects and therapeutic value of a 500 mg implant of oestradiol benzoate was observed in thirty-nine Thoroughbred brood mares showing various abnormalities of the ovary and/or the reproductive tract. Sixteen similarly affected, untreated mares acted as controls. The implant was inserted during the early part of the normal anoestrous period and was removed 6 to 10 weeks later. The conception rate among the treated group (59%) during the onset of the ensuing breeding season was significantly higher (P less than 0-02) than that in the control group. The value of this form of treatment in septic endometritis and as an anabolic aid in cases of immaturity is also discussed.


The frequency of infertility in thoroughbred mares. In a group of 852 Thoroughbred mares, 69-7% had foals which survived beyond 6 weeks, 7-1% had dead, premature or full-term foals and 1-1% had foals which died within 6 weeks after birth. Possible factors which may have influenced these data are mentioned.


Control of fertility in Thoroughbred horses in West Germany. A central control system for German Thoroughbred horses is described. Autumn examination of mares and stallions enables them to be classified according to breeding potential. The results of 25 years of study are reported.


Survey of reproductive efficiency in the Quarter-horse and Thoroughbred. Reproductive efficiency was evaluated for 838 Quarter-horse mare-years on five farms and 939 Thoroughbred mare-years on seven farms over 4 years. The pregnancy  rate from first service was 51% for Quarter-horse mares and 43% for Thoroughbred mares (P less than 0-05). The cumulative pregnancy rate after five services was 85% for Quarter-horse and 77% for Thoroughbred mares (P less than 0-05). First-service-period pregnancy rates were 44, 40 and 54% for maiden, barren and foaling mares, respectively. Cumulative pregnancy rates after five service-periods were 84, 74 and 84% for maiden, barren and foaling mares, respectively. The pregnancy rate for foaling mares served during foal heat was lower (P less than 0-05) than the first-servicd pregnancy rate of foaling mares served after the foal heat. Less than 40% of the maiden mares, less than 50% of the barren mares and less than 30% of the foaling mares were submitted for their first-service-periods by the end of March.


Pelviscopy in the mare.

Pelviscopy in the mare. A method of endoscopic examination of the internal genital (pelvic) organs of the mare is described. Special emphasis is placed on the induction of artificial pneumoperitoneum and the installation of an endoscopic peritoneal fistula device for prolonged observation. The potential of pelviscopy in the mare as a diagnostic aid, a new device for research in equine reproduction and as an auxillary aid to teaching is discussed.


The distribution of delta5-3beta-hydroxysteroid dehydrogenase in the graafian follicle of the mare. Graafian follicles of various sizes obtained from mares at different stages of the oestrous cycle were examined histologically and histochemically for delta5-3beta-hydroxysteroid dehydrogenase (3beta-HSD) activity and related enzymes. The 3beta-HSD activity was not found in the theca interna of any follicles but was present in the membrana granulosa of well-vascularized large follicles in the late luteal phase of the cycle and at oestrus. These findings indicate that pregnenolone cannot be converted into progesterone in the theca interna. It is suggested that this conversion occurs in the membrana granulosa and that progesterone then passes into the theca interna where it is converted into oestrogen. Participation of both granulosa and thecal cells in oestrogen production is also discussed from a morphological view-point.


The site of ovulation in the mare.

The site of ovulation in the mare. Serial photography of the ovary of a mare by periodic surgical exteriorization of the ovary and peritonescopy in situ revealed that the ovulatory fossa is the site of ovulation in this species.


Clinical management of equine ovarian neoplasms. The rarity of equine ovarian neoplasms is attested to by the lack of reports in the literature. However, sixteen cases have been diagnosed at the Iowa State University Veterinary Hospital in the last 3 years and, of these, the granulosa-cell tumour was the most common. A study of the clinical and subsequent histories of these and other mares reveals some common findings as to age, breed, reproductive status, clinical signs, and post-surgical reproductive capability.


Selected pathological changes of the mare uterus and ovary. Focal enlargements of the uterus are palpable through the rectal wall and have various aetiology. Aspects of their diagnosis, possible pathogenesis, significance and treatment are presented. Lymphatic lacunae appear to be quite common in older mares and may occasionally give rise to large endometrial cyst, but more frequently cause widespread change throughout the uterine horns. Three unusual ovarian abnormalities are presented, a large, oestrogen-producing granulosa cell tumour, an oestrogen-producing large follicle in a 4-month-old filly, and an ectopic progesterone-producing adrenal structure bordering on neoplasia.


Endometrial biopsy as a guide to diagnosis of endometrial pathology in the mare. A safe and simple technique of endometrial biopsy is described which the results suggest is a useful adjunct to the diagnosis of suspected pathological conditions of the uterus. In conjunction with other clinical data and a knowledge of the breeding history, histopathological findings form a basis for prognosis and treatment of the subfertile mare. A system of classification is presented as a basis for continuing work on the correlation of endometrial histopathology with fertility and breeding potential.


Candida infection of the genital tract in thoroughbred mares. This paper describes sixteen cases of Candida infection of the genital tract in Thoroughbred mares. Clinical signs and histopathological lesions of the disease are described and the results of treatment with Lugol's solution and Nystatin are given.


Endometritis, a common cause of infertility in mares. Infertility, resulting from failure to conceive during the preceding breeding season, was caused by various forms of endometritis in forty-four mares of Highland and Arabian breeds in Yugoslavia. Chronic mucopurulent and latent catarrhal endometritis occurred most frequently. Douching of the uterus on alternate days for 9 days with warm and cold sterile salt solutions (ranging from 7% to 1% w/v) in the early autumn resulted in conception in 47-7% of mares at an average of 15-2 days after the onset of treatment, and another 36-7% becoming pregnant in the following spring. Mating at the wrong stage of the oestrous cycle and too frequent mating during oestrus were judged to be the most common causes of endometritis in the mares examined.


Cytogenetic studies of three equine hybrids. A detailed investigation of testicular meiosis in a mule, a hinny and a Przewalski horse/domestic horse hybrid were made. Abnormalities of pairing were observed in the mule and hinny in most germ cells at the pachytene stage of meiotic prophase, and spermatogenesis was alsmot totally arrested. A few mature spermatozoa were recovered from the ejaculate and epididymal flushings of the hinny. The Przewalski horse/domestic horse hybrid was fertile and showed normal spermatogenesis. Chromosome banding studies showed a close homology between the karyotypes of the Prezwalski horse (Equus przewalskii, 2n = 66) and the domestic horse (E. caballus, 2n = 64), and it is evident that a single Robertsonian translocation has occurred transforming four acrocentric chromosomes of E. przewalskii into two metacentric chromosomes in E. caballus. The investigations showed that a trivalent is formed at meiosis in the hybrid (2n = 65), segregation from which gives two classes of genetically balanced spermatozoa. Both of these are capable of producing normal offspring if they fertilize the eggs of a domestic mare.


A review of cytogenetics in equine reproduction. The karyotype of the horse consists of 64 chromosomes; 18 pairs have a terminal centromere and 13 pairs a non-terminal centromere. Identification of individual chromosomes is enhanced by the use of band-staining techniques which allow recognition of minor structural rearrangements of chromatin material. Seven previously reported cases of male pseudohermaphroditism with chromosome studies are reviewed. Three were genetic females, one was basically an XX/XY chimaera, one was an XX/XXY chimaera, and one was an XXXY. Also reviewed is an infertile mare with 63 chromosomes and no distinguishable sex chromosomes and a mare with juvenile genitalia and XO/XX sex chromosomes. It is postulated that, in the future, additional chromosome abnormalities will be found associated with maldevelopment of the equine reproductive system and as a cause of early embryonic death and abortion.


An intersex (male pseudohermaphrodite) horse with 64XX/XXY mosaicism. The clinical, pathological and chromosomal findings in a male pseudohermaphrodite horse are reported. This animal appeared to be a female but showed strong male sexual behaviour. A small penis emerged from a rudimentary vagina. Two small testes were present in the abdomen and undifferentiated seminiferous tubules contained only supporting cells. No uterus was found. Culture of peripheral blood leucocytes revealed a 64XX/65XXY mosaicism.


Chromosome abnormalities as a cause of infertility in mares. Chromosomal abnormalities have been detected in seven mares isolated by their poor reproductive performance. All had small or rudimentary gonads and absent or irregular oestrous cycles. Two mares had an XO genotype, one was a 65,XXX female and another a 64,XY sex-reversed female. Two other mares were sex chromosome mosaics of the 63,X/64,XX type. The seventh mare showed a normal female karyotype but a small extra autosomal fragment was found in a few cells.


Gonadal dysgenesis in the mare.

Gonadal dysgenesis in the mare. Five phenotypically normal but infertile mares were studied; four had karyotypes of 63XO, and one was a 25,64XX/13,63XO mosaic. The mares exhibited small uteri and has small ovaries that lacked germ cells and consisted primarily of undifferentiated ovarian stroma. These cases demonstrate that chromosome analysis is an important technique for the diagnosis of some forms of equine infertility.


Origin and histogenesis of equine endometrial cups. Biochemical and morphological studies were carried out to determine the origin and histogenesis of endometrial cups in mares. A wide range of fetal and maternal tissues were cultured in vitro and their ability to secrete gonadotrophin (PMSG) was monitored. High levels of PMSG were produced in culture only by cells from the restricted area of the equine trophoblast known as the chorionic girdle which is an annular band of highly specialized cells at the junction of the allantois and the regressing yolk sac. The morphological appearance of girdle cells after cultivation in vitro and after allogeneic grafting to the uterus or testis was identical to that of endometrial cup cells. Firm attachment between the cells of the chorionic girdle and the adjacent endometrium occurs on Day 36. Girdle cells then rapidly invade and phagocytose the endometrial epithelium, and migrate into the endometrial glands and the uterine stroma where they differentiate into large, sessile endometrial cup cells.


The ultrastructure of endometrial cups in pregnant mares. Electron microscopy and immunofluorescence techniques were used to study the various epithelial cells in the endometrial cups of ten pregnant mares, and in the uterine epithelium of one non-pregnant mare. Evidence was obtained which suggested that epithelial gland cells within the endometrial cups, as distinct from the hypertrophied decidual-like cells in the cup, may synthesize PMSG. The suggestion does not agree with the findings of other workers in the fetal origin (chorionic girdle cells) of this gonadotrophin.


The influence of fetal genotype upon endometrial cup development and PMSG and progestagen production in equids. The influence of fetal genotype upon gonadotrophin (PMSG) and progestagen production in mares and donkeys during the first half of pregnancy was examined. The production of PMSG was greatly reduced in mares carrying mule conceptuses and greatly increased in donkeys carrying hinny conceptuses. Fetal genotype had no obvious influence upon progestagen production in mares, but donkeys carrying hinny conceptuses showed extremely high peripheral plasma progestagen concentrations when serum PMSG levels were elevated. Fetal genotype profoundly influences the intensity and rate of success of the maternal leucocyte response directed against the endometrial cups. The suggestion is advanced that PMSG may constitute an immuno-protective barrier around endometrial cup cells which partly protects the cells from attack by sensitized maternal lymphocytes.


Some aspects of endometrial cup formation and PMSG production. Two females of heterosexual pairs of chimaeric horse twins were fertilized by their co-twin brother and PMSG production examined during gestation. Four pregnancies developed in one mare and two in the other. The levels of PMSG were high in both mares and remained detectable in the peripheral blood until 220 and 265 days of gestation. The fetal membranes of one mare contained remnants of cup secretion with PMSG activity at term. The findings support the thesis of Allen & Moor (1972) that the endometrial cups are of fetal origin and that they are destroyed by immunological mechanisms.


Plasma progestagens in pregnant mares.

Plasma progestagens in pregnant mares. Peripheral plasma progestagens were quantified by a competitive protein-binding assay throughout pregnancy. The level of progesterone increased significantly between Days 0 and 8 (P less than 0-05) and again between Days 28 and 44 and reached a maximum on Day 64. Subsequently, it fell slowly until about Day 300 and then rose again during the last 30 days before reaching a minimum on the day after foaling. Very low concentrations of 17alpha-hydroxyprogesterone were found except between Days 40 and 120 and during the last 30 days before birth. Two unidentified compounds, one eluting slightly before and one after progesterone on Sephadex LH-20 columns, first appeared in plasma between Days 30 and 60 of gestation, and increased gradually to Day 300. Both compounds increased significantly (P less than 0-05) at about 5 days before birth and were not detectable on the day after foaling.


Ovarian changes during early pregnancy in pony mares in relation to PMSG production. The ovaries of twenty pregnant mares were examined daily, per rectum, for the first 4 months of gestation and note was made of their estimated size and follicular content. Serial blood samples from sixteen of the mares were assayed for PMSG. A marked seasonal effect was noted on ovarian size, follicular content and ovulation rate during pregnancy but there was no such effect on PMSG production. It is concluded that PMSG is synergistic with gonadotrophins of pituitary origin and that the latter hormone are the primary stimulus on the ovary of the pregnant horse.


Follicular and luteal development in pregnant mares. Examination of the ovaries of mares at various stages of pregnancy and after hysterectomy, together with measurement of progesterone concentrations in the peripheral plasma of pregnant and hysterectomized mares and in uterine and ovarian venous plasma of pregnant mares, demonstrated that the primary CL of pregnancy remains functional until at least Day 160 of gestation. The results showed that primary and secondary CL, and the placenta or uterus, all contribute to the total progesterone pool in mares during pregnancy. Similarities and differences in ovarian function observed between pregnant and hysterectomized mares suggested that, while PMSG does not appear to stimulate follicular development, it does prolong the life-span and stimulate the secretory activity of the primary CL, and induces ovulation and/or luteinization of secondary follicles in pregnant mares.


Plasma progestagens in the pregnant mare in the first and last 90 days of gestation. Plasma progestagens were measured in eighteen pregnant mares to establish normal levels in the first and last 90 days of gestation. Progestagens increased from 25 ng/ml at 90 days before birth to 60 ng/ml at 10 days before birth, decreased to 58 ng/ml at 5 days before, and were 3 ng/ml or less by 5 days after perturition. During the first 90 days of pregnancy, progestagens reflected luteal activity with an increase in plasma levels from Day 30 to Day 60.


Plasma progestagens in cyclic, pregnant and post-partum mares. The pattern of plasma progestagen levels during the oestrous cycle was similar to that previously reported except for lower peak levels. The lack of significant difference (p less than 0-01) between CPBA and RIA values suggests that progesterone itself is the major component during the oestrous cycle. Progesterone levels during the first and second post-parturient oestrous cycles were similar to those observed during the cycle of the non-pregnant mare. During pregnancy there were two peaks of plasma progestagens. The first, which occurred during the 3rd month, coincided with high levels of PMSG and was probably produced by the endometrial cups or the secondary CL. The second peak occurred in the 11th month and probably represented the secretion of placental progestagens. At least two unknown progesterone (?) metabolites were present which cross-reacted in the CPBA and RIA systems and probably contributed to the high progestagen values obtained in late pregnancy when chromatography was excluded from the assay procedures. Progestagen levels dropped precipitously after parturition and was probably due to placental separation from the endometrium. The higher progesterone levels in the newborn foal and other evidence suggests that this hormone is produced by the fetal gonads.


Endocrine patterns of the mare at term.

Endocrine patterns of the mare at term. The levels of progesterone and total progestins increased during late pregnancy and then fell dramatically during the last few days before parturition, although birth occurred in the presence of significant amounts of plasma progesterone. Oestrogen levels decreased slowly but insignificantly until birth occurred, and then remained at a low level until the post-partum oestrus 10 to 12 days later. Total 11beta-hydroxycorticosteroids were unchanged from Day 45 before to Day 15 after birth. The endocrine pattern of one ovariectomized pregnant mare during the last month of gestation was similar to that of the intact mares. A normal cyclic progesterone and total progestin pattern was observed at the post-partum ovulation. Oestrogen levels did not change significantly but corticosteroid levels increased significantly between Days 15 and 22 post partum. Progestin, oestrogen and corticosteroid levels during the first 24 hr after birth were consistently higher in the foal than in the maternal plasma.


Oestrogens, LH, PMSG, and prolactin in serum of pregnant mares. Levels of oestrone, equilin and equilenin (E1), oestradiol (E2) LH, PMSG and prolactin were measured by radioimmunoassay in serum from pregnant mares. Levels of E1 were always greater than those of E2. Both E1 and E2 remained at low levels until Day 80, increased significantly (P less than 0-05) by Day 120 to reach peak levels at Day 210 or 240 and then declined until parturition. Maximum levels of oestrogens observed in this study were 828 +/- 151 pg/ml for E1 and 71 +/- 18 pg/ml for E2 at Days 210 and 240 respectively. Spikes of LH release were observed in early pregnancy in most mares. Levels of PMSG were first detectable at Days 32 or 36 and reached a peak of 67-1 i.u./ml 64 days after the last mating. Levels of LH were very low (often non-detectable) from Day 210 of gestation until parturition. Levels of prolactin were extremely variable and showed no clear fluctuating patterns during pregnancy.


Oestrone and equilin in the plasma of the pregnant mare. A method for the extraction of oestrone and equilin from the plasma of the pregnant mare is described, and the levels obtained for eighty-two samples from fourteen Welsh Mountain Ponies at different stages of pregnancy are recorded. Oestrone (fifteen samples) and equilin (three samples) were not found before Day 120. From Day 120 to 240, oestrone levels exceeded 100 ng/ml and then declined to parturition. The high concentrations of oestrone in mid-pregnancy were associated with gradually increasing concentrations of equilin which tended to plateau after Day 180 at just under 100 ng/ml and declined significantly only in the last month of pregnancy. Evidence is presented that both oestrone and equilin occur in peripheral plasma largely as sulphates.


Biochemistry of stallion semen.

Biochemistry of stallion semen. Stallion semen has several chemical characteristics not commonly encountered in other animals. It contains very little fructose and the spermatozoa possess only limited fructolytic ability under anaerobic conditions. By determining some of the characteristic constituents such as ergothioneine, citric acid, glycerylphosphorylcholine and certain glycosidases, it is possible to obtain a quantitative measure of the secretory contribution of the ampulla, seminal vesicle and epididymis, respectively, towards the final composition of the whole ejaculate. By analysing separately the various fractions of a split ejaculate, including the so-called tail-end sample, it is possible to detect and pinpoint abnormalities in the functional state of the various male accessory organs and in the entire process of ejaculation.


Factors influencing foaling percentages in Australian mares. Foaling figures for Thoroughbred mares in Australia show a puzzling disparity between conception and foaling rates in the second half of the 22 years of official data collection between 1950 and 1972. In the first 9 years of the survey, the live foal percentages rose in parallel with conception rates, but then a divergence of the figures occurred with the conception rate continuing to improve by 6-25% while the foaling rate improved by only 0-01% over the same period. An hypothesis supported by data from two studs is considered that stress factors additional to those experienced by mares in the earlier years may be responsible for the regression of the foaling figures.


Early pregnancy testing and its relationship to abortion. A total of 487 Standardbred and Thoroughbred mares at two studs were manually tested for pregnancy at 20 to 24, 30 to 34, and greater than 42 days after service and the abortion rate compared to that obtained in previous years when only the greater than 42-day test was performed. The results indicated that early manual pregnancy testing does not increase the abortion rate if undertaken carefully and enables non-pregnant mares to be re-mated earlier in the same season.


Comparison of the methods of rectal palpation and haemagglutination-inhibition assay for diagnosis of pregnancy in mares. The diagnostic value of rectal palpation and immunological assay of PMSG was tested at different stages of pregnancy in mares inseminated with frozen semen in three separate studies. The results were based on foaling success and particular attention was paid to the numbers of inconsistent results obtained by the two tests. Generally, the number of false positive diagnoses was lower for the immunological assay than for palpation in early pregnancy (Days 40 to 60) and the relationship became reversed later in gestation.


Embryological studies on the dartmoor pony during the first third of gestation. A sequence of ten known-age embryos recovered from Dartmoor Ponies during the first 4 months of gestation is described. Changes in size, shape and vascularity of the conceptus are recorded, as well as the growth and decline of the yolk-sac and the succeeding establishment of the allantochorion. The progress of equine somatogenesis is compared with that of the pig which it lags on average of about 4 days. Some quantitative data are presented.


Development of the equine fetus and placenta. Prenatal specimens from mares with known breeding dates were used to characterize morphological changes in the fetus and placenta of pony mares. Prenatal characteristics and the day on which each was first found and weights of different components of the equine conceptus are summarized.


Retention of tubal eggs in mares.

Retention of tubal eggs in mares. Genital tracts from 227 mares slaughtered in various reproductive states were investigated to study egg retention in the oviducts. Eggs were found in 88-2% of 212 non-pregnant mares; the number/mare ranged from 0 to 21, and averaged 4-34. Retained eggs were twice as common in heavy as in light breeds and were found more frequently in early than in late pregnancy. Eggs were not found in the oviducts of two anovulatory post-partum mares. A few globular masses, probably consisting of desquamated tubal mucosa, were frequently lodged in the distal region of the ampulla and appeared, to some extent to cause the retention of more eggs.


A survey of eggs in the oviducts of mares. A total of 424 eggs was recovered from flushings of 176 pairs of oviducts. Of these eggs, 324 were in a state of advanced degeneration (Type 4) and ten appeared to have been recently ovulated (Type 1). The number of eggs/oviduct varied from 0 to 13, most being up to 3 eggs, but fifty oviducts contained no eggs. It is widely believed that unfertilized ova are selectively retained in the oviducts but an alternative explanation for their presence is put forward.


A surgical technique applied to the study of tubal eggs in the mare. An efficient surgical technique of collecting eggs from the oviducts of mares is described. Within 6 days after ovulation recovery was successful in 22/29 mares. The technique has been used to investigate the retention and ageing of eggs in the oviducts and to determine the origin and the nature of the accessory CL during pregnancy.


Surgical and non-surgical egg transfer in horses. Surgical and non-surgical methods used for the recovery and transfer of fertilized horse eggs are described. Sixteen of the twenty-three zygotes recovered surgically between Days 1 to 6 after ovulation from thirty donor mares were transferred surgically to synchronized recipients; seven pregnancies resulted. Seven of the eleven zygotes recovered non-surgically between Days 6 to 8 after ovulation from twenty-eight donor mares were transferred non-surgically to synchronized recipients; five pregnancies resulted.


Spermatogenesis and duration of transit of spermatozoa through the excurrent ducts of stallions. The cycle of the seminiferous epithelium was divided into eight stages on the basis of meiotic divisions, shape of the spermatid nuclei and location of the spermatids with elongated nuclei. Duration of this cycle was 12-2 days (S.E. +/- 0-1) as determined by [3H]thymidine injections and autoradiography. The life-span of primary spermatocytes was 19-0 days, secondary spermatocytes 0-7 days, spermatids with round nuclei 8-7 days, and spermatids with elongated nuclei 10-1 days. Labelled spermatozoa entered the caput epididymidis 35 days, and appeared in the ejaculate 39-9 days, after the isotope injection. The mean minimal time required for spermatozoa to pass through the excurrent ducts was 4-9 days. However, the average transit time was estimated to be between 8 and 11 days. Variation in the duration of the cycle between species is discussed.


Observations on reproductive performance in the yearling mare. Reproductive performance was studied in 137 yearling mares run with stallions in small groups for 3 months between June and August in 1968 to 1971 (four breeding seasons). Pregnancy diagnosis by repeated rectal palpation and qualitative tests for PMSG, showed that ninety-five mares conceived of which forty-four aborted spontaneously between Days 30 and 160 of gestation. Laboratory examination of twenty-one aborted fetuses failed to show any infectious agents. Serial quantitative and qualitative tests for PMSG in aborting animals gave results similar to those observed in mares with normal pregnancies. Plasma progestagen assays showed marked individual variations although the loss of the conceptus was always associated with a drop in progestagen level. The high incidence of early pregnancy loss in these pubertal mares may also be related to immaturity, inadequate nutrition and physical stress.


Germ cell development and the meiotic prophase in the fetal horse ovary. A histological study of the developing germinal epithelium in the fetal horse ovary shows an enormous wastage of oocytes during the meiotic phase, between Days 73 and 150 of pregnancy. The first groups of oocytes to enter this phage undergo mass degeneration and eventually disappear; few, if any, oocytes develop to primordial follicles. Peripheral oogonia, dividing by mitosis, give rise to more oocytes which pass through the same changes and are also reduced by degeneration, but by Day 150 primordial follicles are fairly common.


Development of pituitary and adrenal glands in the fetal horse. The various cell types in the adult anterior pituitary may be distinguished at the ultrastructural level of the sizes of the secretory granules within the cytoplasm. In the fetal adenohypophysis, with the exception of prolactin-producing cells, all types may be identified after Day 100 of gestation. Morphological evidence suggests that they are producing and secreting trophic hormones. The three constituent layers of the adrenal cortex are also discernible by Day 100 of pregnancy. The cells of the zona glomerulosa have large numbers of darkly stained inclusions within the cytoplasm. The zona fasciculata shows changes consistent with the production and secretion of steroid hormones.


An ultrastructural and histochemical study of the interstitial cells in the gonads of the fetal horse. Gonadal tissue obtained at about 50-day intervals from Days 60 to 300 of gestation was examined histologically, histochemically and in the electron microscope. The marked enlargement of the gonads (ovaries or testes) reached a peak around Day 250 and was caused by hypertrophy and hypoplasia of interstitial cells. These cells had all the ultrastructural characteristics of a steroid-secreting cell but delta5-3beta-hydroxysteroid dehydrogenase (3beta-HSD) was not detected at any stage of their development. There was no significant change in the ultrastructure of the interstitial cells between Days 100 and 250 except for a progressive increase in the number of dense bodies. By Day 300 the fetal gonads had begun to regress and degenerative changes were apparent in the interstitial cells. The possible mechanisms controlling the growth of the fetal gonads and their function in steroidogenesis is discussed.


Fine structure of the gonads of the horse and its functional implications. Light and electron microscopic studies of the gonads of the fetal horse have shown that, in their hypertrophic condition which begins during the 3rd month, the interstitial cells contain large amounts of smooth endoplasmic reticulum, suggesting a secretory activity. Hydroxylating activity which was cytochrome P-450-dependent was observed in the fetal testis and may be involved in steroid biosynthesis.


A histochemical study of steroid metabolism in the equine fetus and placenta. The distribution of several hydroxysteroid dehydrogenases (HSD) was examined in a variety of equine placental and fetal tissues. The main points of interest were: (a) the lack of dehydrogenase activity in the gonad, (b) the appearance of a variety of HSDs in the trophoblast as early as 13 days of gestation, (c) the histochemical similarity between the cells of the trophoblast and the endometrial cup, and (d) the restriction of the strong endometrial 17beta-HSD reaction to those parts of the uterine epithelium directly apposed to the trophoblast.


Ultrastructural development of the equine placenta. Microcotyledons, which are a distinctive feature of the mature equine placenta, are fully formed by Day 150 of gestation. The fetal component of each microcotyledon is developed from several primary folds of trophoblast which become elaborately subdivided as gestation proceeds. These changes are reflected in the structure of the maternal crypts, which receive the fetal villi. Between Days 60 and 150 of gestation the maternal epithelium is greatly reduced in height. No such change occurs on the fetal side of the placenta, but between Days 100 and 250 a progressive indentation of the epithelium by fetal capillaries reduces the effective thickness of the placental barrier. The ultrastructural characteristics of fetal and maternal epithelia are described.


Anatomy of the placental barrier in the mare. The study of the equine placenta, which began in Venice in 1598, has a long but discontinuous history. Early observations were purely morphological, but new techniques have stimulated a broader and more functional approach. Histological and ultrastructural observations at various stages of pregnancy have shown that the fetal side of the placenta comes to acquire certain features in common with the air-blood barrier of the mammalian lung. These changes may reflect the increasing O2 requirements of the fetus as gestation proceeds.


The use of intravascular catheters for long-term studies on the mare and fetus. Methods developed for the insertion of catheters into the umbilical artery and vein and the uterine vein of the pregnancy mare are described. The technique requires careful anaesthesia and the maintenance of normal blood gas tensions, pH and arterial blood pressure. Fetal survival was variable: three mares delivered live foals and six fetuses survived more than 15 days with a maximal period of 41 days. The erythrocytes sedimentation rate (ESR) of the fetal foal was always very low at operation but subsequently increased slightly; a sudden large rise in ESR usually indicated imminent fetal death. The relatively sudden death in utero of catheterized fetuses maintained for 10 days or more remains unexplained. Nevertheless, the stability and relatively long duration of some of these preparations are sufficient to investigate various aspects of placental exchange and the endocrine climate of the fetus.


Characteristics of the successive jets of ejaculated semen of stallions. The use of an 'open' artificial vagina made it possible to separate the individual jets in the ejaculate of the stallion. A total of 132 jets were collected in this way from twenty-one ejaculates. After macro- and microscopic examination and sperm counting, glycerylphosphorylcholine (GPC), ergothioneine and fructose levels were determined for every jet. The values obtained for the first three jets were similar and accounted for about 76% of all spermatozoa, and 70% of GPC. These jets also contained the highest concentration of ergothioneine and fructose.


Ontogeny of equine haemoglobins.

Ontogeny of equine haemoglobins. Studies were made of the O2 affinities of fetal and maternal haemoglobins in the horse, and correlations were found with erythrocytic levels of 2,3-diphosphoglycerate.


Morphology and pathology of the equine umbilical cord. A brief description is given of the morphology of the umbilical cord and some variations encountered. In 95% of normal Thoroughbred foals the cord measures less than 84 cm. Factors which govern cord length are not known. Seven pathological conditions involving the umbilical cord are described. Increased length is the most common abnormality and predisposes to three potentially lethal conditions, strangulation of the cord around the fetus, excessive torsion, and allantochorionic necrosis at the cervical pole.


Plasma progestagens and oestrogens in fetus and mother in late pregnancy. Normal Thoroughbred and catheterized Pony mares and their fetuses were used. Fetal oestrogen and progestagen concentrations in late gestation were much higher than maternal values. A major feature of the umbilical steroid concentrations was a large venous-arterial difference in progestagens and total oestrogens throughout late gestation which may indicate a metabolic cycle in the fetus between progesterone and other steroid metabolites. Metabolites of 20alpha-dihydroprogesterone were present in high concentrations in maternal and fetal plasma. In Thoroughbreds, and to a lesser extent in Pony mares, plasma progestagens rose towards parturition while total plasma oestrogen fell. The only oestrogen which showed a rise in concentration near term was oestradiol-17beta. In one Pony mare and fetus, fetal plasma progestagen fell 24 to 36 hr before parturition when maternal peripheral progestagen concentrations remained high.


Studies on fetal, neonatal and maternal cortisol metabolism in the mare. Fetal plasma cortisol concentrations (mean +/- S.E.M.) in ten animals with indwelling umbilical catheters ranged from 13-9 +/- 1-5 ng/ml (227 to 244 days) to 18-1 +/- 2-2 ng/ml (290 to 310 days). Maternal values did not change over this period (15-9 +/- 1-7 ng/ml). Fetal cortisol production rates in two fetuses were 3-6 and 3-8 mg/kg/day at 291 days; there was little placental transfer of cortisol. In three fetuses (319 to 321 days) plasma cortisol values 1 to 10 days before birth were higher (30 to 50 ng/ml) than in any other group, and at birth the values were comparable with those found in intact Thoroughbred foals at birth. After birth plasma cortisol concentrations fell rapidly in most foals, but very high values were found in two foals with postnatal convulsions. Plasma cortisol levles remained low in two Thoroughbred foals born prematurely: similar values were found in one catheterized foal both before and after parturition.


Sperm transport and distribution in the mare. Fifty mares were inseminated on Days 2, 4, 7, 11 or 17 of the oestrous cycle with spermatozoa from one of three stallions to observe the distribution of the spermatozoa in various parts of the reproductive tract 12 hr later (Days 3, 5, 8, 12 and 18). Only 0-06 to 2-21% of inseminated spermatozoa were recovered from the tract. More (P less than 0-05) spermatozoa were recovered from the cervix and uterus on Day 12 than on Days 3, 5, 8 and 18. The mean number of spermatozoa recovered from either or both oviducts was significantly greater (P less than 0-10) on Days 5 and 8 than on Days 3, 12 and 18. More spermatozoa were recovered from the right than the left oviduct and the number recovered from the oviducts was significantly (P less than 0-05) influenced by the stallion.


Studies on mild composition and lactogenic hormones in the mare. Small samples of mammary secretion were collected from eight Thoroughbred mares during the last week of pregnancy, at foaling and after 1 week of lactation. Specific assays showed the presence of both lactose and triglyceride in all samples before birth and progressive increases in their concentrations in colostrum and in milk. Levels of 6-0 g lactose/100 ml and 1-8 g triglyceride/100 ml were present in milk at 7 to 9 days post partum. The secretory capacity of the udder is thus normally established well before parturition in the mare. Attempts to demonstrate the occurrence of a placental lactogen and to measure lactogenic hormones in plasma have been unsuccessful.


The effect of a corticosteroid (dexamethasone), progesterone, oestrogen and prostaglandin F2alpha on gestation length in normal and ovariectomized mares. Dexamethasone (100 mg/day) injected from Days 318 to 324 of pregnancy induced parturition. Progesterone (500 mg/day) administered daily from Day 318 of pregnancy also shortened gestation while oestrogen (50 mg/day) administered on the same schedule as progesterone had no such effect. Dexamethasone treatment superimposed on the oestrogen or progesterone treatments shortened gestation. Prostaglandin F2alpha alone did not induce parturition, unlike PGF2alpha with dexamethasone, or PGF2alpha given to ovariectomized mares.


Induction of parturition in mares.

Induction of parturition in mares. Thirty-seven induced parturitions involving thirty-one mares were studied over a 2-year period using various doses of oestrogen and oxytocin. The time of appearance and degree of expression of the major clinical signs of parturition, and the time for completion of delivery and the passage of the placenta were significantly influenced by increasing doses of oxytocin. Oestrogen was useful in softening and relaxing the cervix when it was tight, but was not essential to induction when the cervix was already soft and dilating. Fertility was not adversely affected by induced parturition.


Patterns of urinary oestrogen excretion in individual pregnant mares. Urine collections (24 hr) were made at weekly intervals from four Pony mares from the 3rd or 4th month of pregnancy until parturition. Separation of oestrogens on Celite columns was followed by Kober measurements of oestrone and equilin. Individual differences were noted in peak amounts of total oestrogens excreted (200 to 800 mg/day), when oestrone constituted 80 to 95% at the 6th to 7th months. Although equilin increased in later gestation, oestrone remained the major product. Total oestrogen values decreased rapidly from the peak and then more gradually towards the end of pregnancy. During the last 3 weeks the decline in the ratio of oestrone to equilin was reversed in all mares.


The development of the lung and its surfactant in the foal and in other species. The development of the lung from the glandular through the canalicular to the alveolar stages in the horse fetus is described. Traces of surfactant and occasional lamellated osmiophilic bodies representing intracellular surfactant were found at 150 days of gestation, some 40 to 60 days before the transition to the canalicular stage. During this transition some of the cuboidal cells of the glandular rosettes are transformed into cells of Types I and II, but the surfactant is not fully developed until 300 days or, in some foals, until after delivery.


Surfactant studies in the fetal and neonatal foal. Phospholipids in embryonic lung tissue, pulmonary washings and amniotic fluid were measured to study the development of lyng surfactant in the horse. A significant increase in the concentration of total phospholipids in lung tissue and a concomitant rise in the amount of dipalmitoyl lecithin in amniotic fluid between 100 and 150 days of gestation indicated the initial formation of surfactant in the fetal lung during this period.


Postnatal lung growth and function in the foal. Respiratory function in newborn foals is discussed with particular reference to the important part played by functional residual capacity and chest wall compliance in maintaining blood gaseous exchange within normal limits.


Studies on pressure-volume relationships in excised equine lungs. Forty-eight lungs from fetal and neonatal horses were examined for pressure-volume relationships between pressures of 0 and 40 cmH2O. The inflation-deflation curves obtained were analysed by four different methods and the stability of the lung assessed in terms of hysteresis, stability indices and volume of air retained at maximal pressure (Vmax). Differences in the shape of the deflation curve between ventilated and non-ventilated lungs were similar to findings in other species. It is postulated that breathing alters lung-tissue elasticity during the neonatal period, as demonstrated by a significant increase in Vmax in specimens from foals breathing for more than 24 hr compared with those from stillborn foals or those aged less than 24 hr. Also, stability indices, such as those expressed by the % of air retained in the lungs on deflation from Vmax to 10 or 5 cmH2O pressure, are related to interfacial factors.


Aspects of respiration in anaesthetized newborn foals. The arterial oxygen tension (PaO2) in clinically normal newborn foals at 1300 m above sea-level is considerably lower (less than 60 mmHg) than in similarly aged foals at lower altitudes. This figure is further reduced to less than 50 mmHg without adverse effect in newborn foals at 1300 m maintained under pentobarbitone anaesthesia for prolonged periods. Measurement of O2 dissociation curves indicates that haemoglobin becomes saturated at a lower blood O2 tension in newborn foals than adult horses.


Neuropathology of the convulsive foal syndrome. Brains from eighteen Thoroughbred foals suffering from the convulsive foal syndrome were examined neuropathologically and compared with brains from nine foals dying from different causes. In the brains of nine convulsive foals there was necrosis of the cerebral cortex, accompanied in three by severe necrosis of the diencephalon and brain stem; haemorrhage into the cerebral cortex was also present in most of this group. In the other nine brains from convulsive foals there was haemorrhage, often severe, especially in the white and grey matter of the cerebral cortex and in the cerebellum. Minimal haemorrhage occurred in the brains of the control group of animals, except in that from one Caesarian-delivered premature foal that suffered severe haemorrhage into the brain stem and cerebellum. Both types of lesion in the convulsive foal appeared to be related to events occurring just before, during or after birth.


Preliminary observations on cranial cardiovascular changes during asphyxia in the newborn foal. This paper describes preliminary experiments designed to test the hypothesis that cerebral damage is caused by cardiovascular events involving explosive changes in cerebral blood flow during birth. These events may be responsible for the convulsive episodes of foals suffering from the neonatal maladjustment syndrome.


Social organization and reproduction in equids. There are two distinct types of social organization and, accordingly, two types of mating systems in equids. In the horse, Plains zebra and Mountain zebra, the adults live in non-territorial and cohesive one-male groups and in stallion groups. The family stallions have exclusive mating rights which are respected by all others. In Grevy's zebra and in the African and Asiatic wild asses, the stallions are permanently territorial and have exclusive mating rights within their territories. Ecological and evolutionary aspects are discussed.


Postnatal changes in total and free thyroxine and triiodothyronine in foal serum. Total tyhroxine (TT4), free thyroxine (FT4), total triiodothyronine (TT3) and free triiodothyronine (FT3) concentrations in foal umbilical cord blood were respectively 14, 5 7 and 3 times the concentrations of these hormones in adult horse blood. The TT4 levels in foals declined rapidly to reach adult concentrations by Day 16 and FT4 levels declined steadily during the first 3 months of life. Foal TT3 levels rose during the first 10 hr after birth and thereafter declined, although they were still X2-5 higher than adult levels at 3 months of age. Levels of FT3 similarly increased after birth becoming X8 higher than adult levels at 3 days of age. They declined after this time but were still twice the normal adult levels at 3 months of age. Associated with these age changes were an increase in the free hormone percentage and a decrease in binding protein concentration. The very high levels of thyroid hormones in newborn foals may be responsible for their extremely high thermogenic capacity and rapid pre- and post-natal rates of growth, especially of the musculo-skeletal and nervous systems.


The development and distribution of mucosal enzymes in the small intestine of the fetus and young foal. Lactase and cellobiase were detectable in the fetal intestine by the 3rd month of gestation, and although there was little change by the 9th month, maximal levels were reached at birth and steadily declined after 4 months. Conversely maltase, sucrase and trehalase were barely discernible in the fetus, maltase being present at low levels at birth, but all increased during the suckling period to attain adult levels by 7 months of age. Alkaline phosphatase activity matured earlier than did disaccharidase activity. Mucosal enzymes other than alkaline phosphatase were virtually absent from meconium and the large intestine. Continued ingestion of lactose could be detrimental in foals suffering from severe diarrhoea.


Babesiosis in the newborn foal.

Babesiosis in the newborn foal. A short account is given of babesiosis (equine biliary fever) caused by the tick-borne protozoan Babesia equi and B. caballi, endemic in the Cape Province of South Africa. The clinical picture, diagnosis and treatment are described. In the absence of any prophylactic measures, prognosis is poor; control of the parasites in the tick-infested areas is essential.


The transfer of passive immunity to the foal and its relation to immune status after birth. The mechanism of transfer of maternal immunity to the foal is reviewed. Maximal efficiency of macromolecular absorption by specialized cells of the small intestine exists soon after birth. The absorptive cells are progressively replaced by more mature-looking cells incapable of taking up large molecules and the rate of absorption is reduced in a linear decline and ceases completely within 24 hr. Passive antibody levels fall rapidly in the first 4 weeks of life to less than half their original values and have usually completely disappeared by 6 months of age. The foal shows immunological competence soon after birth although appreciable levels of autogenous immunoglobulins are not usually attained until 2 to 3 months of age.


Immunoglobulins produced by the antigenized equine fetus. The foal is born without detectable antibody and except for small amounts of IgM is devoid of immunoglobulins. Intrafetal administration of either Venezuelan equine encephalomyelitis virus (VEE-TC83) or ovine erythrocytes elicited IgGa, IgGb and a trace of IgG(T). The fetal blood VEE-TC83 neutralization titre was higher than the neutralization titre elicited by the same preparation in older horses.


Immunoglobulin metabolism in the neonatal foal. The proteins IgG and IgG(T) are the predominant immunoglobulins in equine colostrum. Their distribution and catabolism were studied in the newborn foal using an isotopic tracer technique. More precise quantitation of the absorption of these immunoglobulins from colostrum is now possible.


The gnotobiotic foal in the study of infectious diseases. A method of rearing germ-free gnotobiotic foals is described. To date, four foals have been infected with rhinopneumonitis and the only clinical signs of infection have been a transient fever and leukopaenia; no detailed results are, as yet, available.


Semen characteristics in thyroidectomized stallions. Three Quarter-horse stallions were surgically thyroidectomized at 18 months of age. Weekly semen collections were made from these and three control stallions from 25 to 39 months of age. Although the induced state of hypothyroidism in young stallions has a depressing effect on libido and general animation and can be corrected by thyroprotein supplementation, semen characteristics, testicular histology and fertility are not affected by the operation.


A study of the morphology of stallion semen during the breeding and non-breeding seasons. Season was shown to markedly influence semen characteristics of stallions in Holland, including ejaculate volume, sperm motility, total number of spermatozoa/ejaculate and the percentage of spermatozoa showing morphological abnormalities. Maintenance of normal stallions in continuous light during the winter months and administration of a vitamin and mineral supplement to sub-fertile stallions before the start of the breeding season appeared to improve spermatogenesis significantly.


Studies on the preservation of raw and frozen horse semen. Retention of high motility of horse spermatozoa preserved at 4 degrees C was improved by a semen extender. Raw semen preserved for 2 to 8 hr at 4 degrees C gave an average conception rate of 67-3% but preservation for 1 to 2 days gave an extremely low conception rate. The conception rate from deep-frozen semen during 8 years was 56-3%.


[Tumorous form of acute myeloid leukemia (author's transl)]. The author describes a rare tumorous form of acute myeloid leukemia in a boy aged 4 and a half years. It appeared as unobtrusive swelling of the left upper lid and led to the diagnosis of leukemia. After the beginning of cytostatic therapy the swelling disappeared. In the preterminal state an excessive protrusio of the left globe occured which made the closure of the lid impossible. The right eye was never involved.


Combination of membrane oxygenator support and pulmonary lavage for acute respiratory failure. A 24-year-old woman with chronic granulocytic leukemia and alveolar proteinosis required extracorporeal membrane oxygenator support for respiratory failure refractory to conventional therapy. During perfusion, each lung was lavaged with 10 L. of normal saline. The lavage led to marked clearing of the lungs and improvement in pulmonary function. Extracorporeal support was terminated successfully after 54 hours. The patient died 2 weeks later with bone marrow insufficiency and overwhelming sepsis. Pulmonary lavage is technically feasible during venovenous oxygenator bypass, and may be of value, since such lavage debrides alveoli as well as the bronchial tree. Because pulmonary lavage provides a possible means of improving pulmonary function, it seems worthy of consideration as an adjunct to membrane oxygenator support.


[Classification of skeletal neoplasms (author's transl)]. Complete documentation of the pathological spectrum of a great many similar cancer patients requires interdisciplinary coordination and the absence of ambition of any particular branch. The application of a TNM system devised by the authors for the classification of skeletal neoplasms showed in a retrospective study of 600 cases that the degree of infiltration into the periosteum and soft tissue, which opens more lymphatics to metastasizing tumor cells, is a more relevant parameter of the TNM system than the size of the tumor itself.


[Bone scintigraphy in the diagnosis of primary bone tumors (author's transl)]. Bone scintigraphy has improved greatly since the introduction of bone-seeing short-lived radionuclides. The main field of interest is the search for metastases into bone. The uncharacteristic accumulation of radiopharmaceutical agents in different bone lesions makes specific diagnostic evaluations unlikely. With careful selection of cases, however, scintigraphy can also be used in primary bone tumors as a supplementary means of diagnosis as well as having a positive effect on treatment. Clinical examples are presented to demonstrate the range of application of bone scintigraphy.


[The role of radiotherapy in the treatment of malignant bone tumors (author's transl)]. The role of radiotherapy and adjuvant chemotherapy in the primary treatment of osteogenic sarcomas and of Ewing's sarcoma is reviewed. In osteosarcoma radiotherapy can take the form of prophylactic total irradiation of the lung, but preoperative irradiation of the primary tumor has not proved successful. On the other hand, in Ewing's sarcoma primary and local irradiation is the therapy of choice, and is followed by adjuvant polychemotherapy over a long period.


[Surgical treatment of malignant bone tumors (author's transl)]. The most important therapeutic principles for the surgical treatment of malignant bone tumors are listed, and the technique and value of biopsy are described in detail. General surgical principles of exochleation, resection, amputation, and exarticulation are given. Reconstructuve measures are touched on briefly, and delayed amputation is rejected. Treatment for metastatic disease is described. The most important malignant bone tumors are discussed, together with the most rational treatment for the, including cytostatic and radiation treatment.


[Malignant bone tumours in childhood (author's transl)]. Of the malignant bone tumors that occur in childhood, chondrosarcoma, osteosarcoma, and Ewing's sarcoma are of special interest with regard to therapeutic approach. Whereas in chondrosarcoma radical surgery is the treatment of choice, due to its resistance to radiation, the most efficient treatment for osteosarcoma and Ewing's sarcoma has not yet been clearly defined. In the light of recepnt developments, delayed surgery following initial radiation in osteosarcoma, as advocated by Cade in 1947, has now been superseded by immediate amputation. In Ewing's sarcoma, radiation appears to be superior to surgical intervention, according to recent publications.


[Thrombocythaemia - is there a primary form? ((author's transl)]. Within 5 years 11 patients with thrombocythaemia were admitted to the Department of Internal Medicine, University of Erlangen-Nuremberg. All cases were secondary forms in the course of other myelo-proliferative disorders. In one patient thrombocythaemia preceded the primary disorder for some time. There are some doubts whether the primary form of thrombocythaemia is an entity sui generis.


Adult-onset acid maltase deficiency. Morphologic and biochemical abnormalities reproduced in in cultured muscle. We established muscle-tissue cultures from biopsy of a patient with adult-onset acid maltase deficiency. Morphologically and biochemically, the newly grown fibers of the cultured muscle showed the same abnormalities as those of the biopsied muscle. Light microscopy showed multiple vacuoles filled with acid-phosphatase-positive material; on ultrastructural examination there was abnormal accumulation of glycogen in membrane-bound sacs (secondary lysosomes), some of which also contained dark membranous of homogeneous material. Acid maltase (pH 4.0), a lysosomal enzyme, was undetectable in either cultured or biopsied muscle by maltose hydrolysis, whereas acid phosphatase, also a lysosomal enzyme, was increased in both sources of muscle cells. Cultured muscle fibers demonstrate the same morphologic and biochemical abnormalities characteristic of biopsied muscle, supporting the concept of a biochemically distinct primary myopathy in man.


Dihydrofolate reductase deficiency causing megaloblastic anemia in two families. To determine the cause of severe megaloblastosis detected at birth and at four weeks in two unrelated infants their bone marrow and liver cells were studied. Both patients had abnormal deoxyuridine suppression tests, corrected to normal by 5-formyl tetrahydrofolic acid. Liver-cell homogenate from one patient had a previously undetectable level of dihydrofolate reductase restored to normal by high cation concentration in the assay. Activity of the liver-cell homogenate from the other patient, which was one quarter of the normal level, was restored to only half normal activity by high cation concentration. Dihydrofolic acid reductase deficiency prevents this conversion of folic acid to tetrahydrofolic acid; the enzyme activity appears to differ in each patient. A satisfactory clinical response in both patients followed parenteral therapy with 5-formyl tetrahydrofolic acid. One sibling in each family died of a similar illness. Autosomal recessive inheritance is probable.


[Bone scintigraphy in neurosurgical practice (author's transl)]. Skeletal scintigraphy employing the new 99mTc-labelled compounds-99mTc-diphosphonate and 99mTc-polyphosphate-has proved to be a reliable technique for the detection of primary and metastatic tumors as well as non-neoplastic conditions of the skeletal system including the skull and spine. Recent experiences in 26 consecutive neurosurgical patients are reported. The bone scintigraphy seems to be most valuable in the clinical management of patients suspected of harboring metastatic deposit in the nervous system. In patients with malignancies elsewhere, the incidence of bone metastases is unexpectedly high, but the radiographic survey often fails to reveal the lesions in the initial stage. Bone scintigraphy, on the other hand, is highly reliable in detecting the bone metastases in its earliest stage, and the routine use of bone scintigraphy in such cases would be expected to help avoiding the unnecessary surgical intervention, or changing the plan of management, for example, from surgery to the systemic chemotherapy. Futhermore, bone scintigraphy seems to be useful in selecting the suitable site for biopsy, or in determining the targets for radiation treatment.


The diagnosis of organic tricuspid valve disease. Diagnostic features of organic tricuspid valve disease are discussed with emphasis on clinical features. Cardiac catheter data show considerable differences in assessment as do the chest radiographs. Measurement of the right atrial border from the vertebral edge is a reliable guide to diagnosis.


Sexual activity and contraception use in young adults. 241 (57 male and 184 female), well-educated, largely urban, young persons, voluntarily attended a lecture on sex; after the lecture they completed an anonymous questionnaire on their background, and attitudes to sex. A majority believed that premarital sexual activity was acceptable if there was some affectional tie between the couple. Most of the men were sexually active, while only a third of the women were so. However, a quarter of the sexually inexperienced men and women were engaging in forms of sexual stimulation which would seem to carry a high possibility of ending in intercourse. Knowledge of contraception, while high, tended to over-estimate the efficacy of the safe period and vaginal methods. Half the sexually active group had used contraception at sexual initiation but only a third had used reliable methods. Subsequent contraceptive practice however, was high (90 percent), with the pill being the most frequently used method. Twenty percent of the sexually active women had already been pregnant: of these only a quarter had carried their pregnancies to term. The limitations of the study are discussed and some suggestions for preventing pregnancy in the unmarried drawn.


Ethanolamine oleate and acute renal failure. Two patients suffered from acute renal failure following the use of a larger than usual volume of ethanolamine oleate during the injection of varicose veins. Prominent symptoms of headache, nausea and epigastric pain were associated with the onset of acute renal failure. Spontaneous recovery occurred.


The evaluation of continuing medical education. To use the limited time available for the most benefit, practising doctors need presentations of maximal educational effectiveness. This effectiveness can be assessed by methods which are practical and acceptable. We can evaluate the educational process itself by assessing each presentation using selected criteria, by examining the appropriateness of programme content, and by obtaining the opinions of participants. We can evaluate changes in the knowledge of participants by seeking opinions from them and by building evaluation into educational sessions. We can look at patient-outcome in relation to education by seeking the opinions of informed observers and by building evaluation into clinical work.


New Zealand trends in rheumatic fever: 1885-1971. National statistics of rheumatic fever in New Zealand show falling mortality over the past 30 years. However, morbidity remains high, especially among Maori children. Community-based studies are under way to elucidate this important public health problem.


Infrarenal dissection of the aorta.

Infrarenal dissection of the aorta. Three patients with infrarenal aortic dissection are described and the pathogenesis, investigation and treatment of this condition briefly discussed.


Late recurrence following acute haematogenous osteomyelitis. The results of the treatment of 168 children with acute osteomyelitis in Auckland between 1951 and 1955 were reviewed with a particular interest in late recurrence. The early failure rate of 20 percent is comparable with other recent series. Follow-up of the 134 apparent cures revealed five late recurrences, an incidence of 3.0 percent but follow-up was incomplete (44 cases) and the late recurrence may be higher.


Acute leukemia in advanced ovarian carcinoma after treatment with alkylating agents. Two cases of advanced ovarian carcinoma treated with chlorambucil and terminating in acute leukemia are presented and the literature reviewed. The first patient was diagnosed by laparotomy as having Stage III ovarian carcinoma, and total abdominal hysterectomy and bilateral salpingo-ophorectomy were performed. After 7 years and 2 months of chemotherapy, acute myeloblastic leukemia was diagnosed, and the patient expired 4 months later. At autopsy no residual ovarian tumor was found. The second patient had a right oophorectomy after the diagnosis of Stage III ovarian carcinoma had been made. After 5 years and 9 months of chemotherapy she developed acute myelomonocytic leukemia and expired 2 months later, with residual ovarian tumor present on autopsy. The benefits of surgical reexploration in occasional cases of good clinical remission after chemotherapy are discussed in view of potential carcinogenicity of cytostatic agents.


In vivo fluorine uptake in human enamel following treatment with a varnish containing sodium fluoride. Fluorine concentrations were determined in three successive enamel layers (approximately 10, 10 and 25 microns in width) of 21 pairs of contralateral teeth, by etching with perchloric acid. The F-concentrations in five untreated pairs of teeth were measured and compared (Group I). A decrease in the F-content from about 1100 ppm in the outer layer to 400 ppm at 40 microns from the enamel surface was found. The differences in F-concentrations between contralateral teeth extracted from the same mouth were small and not statistically significant. In five teeth (Group II) th F-uptake was determined one day after a single topical application of a varnish which contained 5% NaF (Duraphat), and compared with the corresponding control contralateral teeth. A significantly increased concentration of F was observed in all analysed enamel layers of the treated teeth: 3270 +/- 128 (1048 +/- 145), 1520 +/- 97 (596 +/- 61), 567 +/- 52 (296 +/- 14) ppm. Values within brackets denote concentrations in control teeth. In another five teeth (Group III) the fluorine concentration was determined one week after a single application of Duraphat. A significant increase in the F-concentrations in three enamel layers of the test-teeth was found as compared to the control-teeth: 1732 +/- 156 (884 +/- 101), 904 +/- 82 (464 +/- 79) and 524 +/- 88 (296 +/- 24) ppm F. The test-teeth in this group contained less fluorine in the outermost enamel than did the teeth in group II. The difference was significant for the outer two layers. Approximately the same concentration of fluorine was found in test-teeth analysed five weeks after treatment as observed at one week, using same varnish (Group IV). The respective values were: 1795 +/- 410 (907 +/- 216), 749 +/- 135 (369 +/- 90), 382 +/- 88 (166 +/- 40) ppm. The F-increase was significant for all enamel layers analysed.


Proton activation analysis studies on fluorine and nitrogen content of developing dental enamel. Proton activation analysis, using the reactions 19F(p, alpha gamma)16O and 15N(p, alpha gamma)12C, was employed to study the fluorine and nitrogen content of developing rat molar enamel at various stages of maturation. Four groups of rats were utilized: Group I -- injected intraperitoneally at 6 days of age with 20 mg F/kg b.w. as sodium fluoride solution and terminated at 30 minutes and 1, 5 and 9 days postinjection; Group II -- injected in a similar way at 7 days of age and terminated 30 minutes and 1, 4 and 8 days postinjection; Group III -- injected with 10 mg F/kg, at 6, 15 and 19 days of age and terminated 30 minutes later; Group IV -- control animals injected with distilled water at 6 and 15 days of age respectively and terminated 30 minutes later. Analysis reflected decreasing nitrogen content in the enamel as maturation proceeded. However, fluorine concentrations were highest in all groups at the earlier stages of enamel development.


Structural studies on polysaccharides synthetised from sucrose by soluble enzymes in human dental plaque material. Soluble enzymes in human dental plaque material were shown to synthetise a polysaccharide material when incubated with sucrose. The polysaccharide mixture was fractionated by gel chromatography and the major fraction (Mw congruent to 95,000) was characterised as a mixture of a alpha-(1 leads to 6)-linked glucan with branches linked alpha-(1 leads to 3) to the main chain and a beta-(2 leads to 6)-linked fructan with branches in the 1-position of the chain residues.