Comparison of Hounsfield units and vertebral bone quality score for the prediction of time to pathologic fracture in mobile spine metastases treated with radiotherapy

OBJECTIVE

Spine metastases are commonly treated with radiotherapy for local tumor control; pathologic fracture is a potential complication of spinal radiotherapy. Both Hounsfield units (HUs) on CT and vertebral bone quality (VBQ) on MRI have been argued to predict stability as measured by odds of pathologic fracture, although it is unclear if there is a difference in the predictive power between the two methodologies. The objective of the present study was to examine whether one methodology is a better predictor of pathologic fracture following radiotherapy for mobile spine metastases.

METHODS

Patients who underwent radiotherapy (conventional external-beam radiation therapy, stereotactic body radiation therapy, or intensity-modulated radiation therapy) for mobile spine (C1-L5) metastases at a tertiary care center were retrospectively identified. Details regarding underlying pathology, patient demographics, and tumor morphology were collected. Vertebral involvement was assessed using the Weinstein-Boriani-Biagini (WBB) system. Bone quality of the non-tumor-involved bone was assessed on both pretreatment CT and MRI. Univariable analyses were conducted to identify independent predictors of fracture, and Kaplan-Meier analyses were used to identify significant predictors of time to pathologic fracture. Stepwise Cox regression analysis was used to determine independent predictors of time to fracture.

RESULTS

One hundred patients were included (mean age 62.7 ± 11.9 years; 61% male), of whom 35 experienced postradiotherapy pathologic fractures. The most common histologies were lung (22%), prostate (21%), breast (14%), and renal cell (13%). On univariable analysis, the mean HUs of the vertebrae adjacent to the fractured vertebra were significantly lower among those experiencing fracture; VBQ was not significantly associated with fracture odds. Survival analysis showed that average HUs ≤ 132, nonprostate pathology, involvement of ≥ 3 vertebral body segments on the WBB system, Spine Instability Neoplastic Score (SINS) ≥ 7, and the presence of axial pain all predicted increased odds of fracture (all p < 0.001). Cox regression found that HUs ≤ 132 (OR 2.533, 95% CI 1.257-5.103; p = 0.009), ≥ 3 WBB vertebral body segments involved (OR 2.376, 95% CI 1.132-4.987; p = 0.022), and axial pain (OR 2.036, 95% CI 0.916-4.526; p = 0.081) predicted increased fracture odds, while prostate pathology predicted decreased odds (OR 0.076, 95% CI 0.009-0.613; p = 0.016). Sensitivity analysis suggested that an HU threshold of ≤ 132 and a SINS of ≥ 7 identified patients at increased risk of fracture.

CONCLUSIONS

The present results suggest that bone density surrogates as measured on CT, but not MRI, can be used to predict the risk of pathologic fracture following radiotherapy for mobile spine metastases. More extensive vertebral body involvement and the presence of mechanical axial pain additionally predict increased fracture odds.

Updates in the Management of Metastatic Spine Disease

The number of cancer diagnoses continues to increase each year in the United States, and given the propensity for bone metastases from solid organ malignancies, orthopaedic spine surgeons will inevitably encounter patients with metastatic spine disease and need to have a framework for approaching the evaluation and treatment of these complex patients. Many patients seeking care for spinal metastases already have a history of disseminated malignancy, but metastatic spine disease itself will be the presenting symptom of cancer in approximately 20% of patients. Because the first presentation of cancer may be to a spine surgeon, an appropriate strategy for the initial evaluation of a patient with a new spinal lesion is critical to establish the diagnosis of metastatic disease before undergoing treatment. Once the diagnosis of metastatic spine disease is confirmed, decisions regarding treatment should be made in coordination with a multidisciplinary team including radiation oncology and medical oncology. Spinal metastases are most often treated with radiation therapy. Direct circumferential decompression of the spinal cord with postoperative radiation therapy is considered for high-grade epidural spinal cord compression to preserve neurologic function. Mechanical spinal instability is another potential indication for surgery. When considering surgery, the patient's medical fitness, systemic burden of cancer, and overall prognosis all must be accounted for, and the importance of multidisciplinary evaluation and shared decision making cannot be overstated.

Improving R0 Resection Rates With a Posterior-First, 2-Stage Approach for En Bloc Resection of Locally Advanced Primary and Recurrent Anorectal Cancers Involving the Deep Pelvic Sidewall

BACKGROUND

Using standard anterior approaches, consistent R0 resection of locally advanced primary and recurrent rectal and anal cancer involving the deep pelvic sidewall may be unattainable. Therefore, to improve R0 resection rates, we have used a posterior-first, then anterior 2-stage approach to resection of tumors in this location.

OBJECTIVE

To assess the R0 resection rate and surgical outcomes of the first 10 patients operated on using this approach.

DESIGN

We conducted a retrospective case series review of our prospectively maintained surgical pathology and tumor registries.

SETTING

This study was conducted at the Mayo Clinic in Rochester, Minnesota.

PATIENTS

Ten patients (6 female individuals, median age 53.5 years) with primary or recurrent anal or rectal cancer treated with a posterior-first, then anterior 2-stage approach were identified.

MAIN OUTCOME MEASURES

The primary outcome measures were the R0 resection rate and surgical outcomes.

RESULTS

An R0 resection was achieved in all 10 patients. Nine patients developed 1 or more 30-day Clavien-Dindo grade III complications. Nine patients developed gluteal wound complications ranging from superficial wound dehiscence to flap necrosis. During the follow-up period, 4 patients were found to have metastatic disease and 1 patient had local re-recurrence.

LIMITATIONS

Small cohort with heterogeneous tumors and a short follow-up duration.

CONCLUSION

A posterior-first, then anterior 2-stage approach has allowed us to achieve consistent R0 resection margins in locally advanced primary and recurrent rectal and anal cancers involving the deep pelvic sidewall. Poor wound healing of the posterior gluteal incision is a common complication. See Video Abstract.

MEJORANDO LAS TASAS DE RESECCIN R CON UN ABORDAJE DE DOS ETAPAS PRIMERO POSTERIOR PARA LA RESECCIN EN BLOQUE DE CNCERES ANORRECTALES PRIMARIOS Y RECURRENTES LOCALMENTE AVANZADOS QUE AFECTAN LA PARED LATERAL PLVICA PROFUNDA

ANTECEDENTES:Utilizando abordajes anteriores estándares, la resección R0 consistente del cáncer de recto y ano primario y recurrente localmente avanzado involucrando la pared lateral pélvica profunda puede ser inalcanzable. Por lo tanto, para mejorar las tasas de resección R0, hemos empleado un abordaje de 2 etapas primero posterior y luego anterior para la resección de tumores en esta ubicación.OBJETIVO:Este estudio tuvo como objetivo evaluar la tasa de resección R0 y los resultados quirúrgicos de los primeros 10 pacientes operados con este abordaje.DISEÑO:Realizamos una revisión retrospectiva de series de casos de nuestros registros de patología quirúrgica y tumores mantenidos prospectivamente.AJUSTE:Este estudio se realizó en la Clínica Mayo en Rochester, Minnesota, EE. UU.PACIENTES:Se identificaron diez pacientes (6 mujeres, mediana de edad 53.5 años) con cáncer anal o rectal primario o recurrente tratados con un abordaje de dos etapas, primero posterior y luego anterior.PRINCIPALES MEDIDAS DE RESULTADO:Las medidas de resultado primarias fueron la tasa de resección R0 y los resultados quirúrgicos.RESULTADOS:Se logró una resección R0 en los 10 pacientes. Nueve pacientes desarrollaron una o más complicaciones de grado III de Clavien-Dindo a los 30 días. Nueve pacientes desarrollaron complicaciones de la herida del glúteo que variaron desde dehiscencia superficial de la herida hasta necrosis del colgajo. Durante el período de seguimiento, se encontró que 4 pacientes tenían enfermedad metastásica y un paciente tuvo recurrencia local.LIMITACIONES:Cohorte pequeño con tumores heterogéneos y corta duración de seguimiento.CONCLUSIÓN:Un abordaje en 2 etapas, primero posterior y luego anterior, nos ha permitido lograr márgenes de resección R0 consistentes en cánceres de recto y anal primarios y recurrentes localmente avanzados que afectan la pared lateral pélvica profunda. La mala cicatrización de la incisión glútea posterior es una complicación común. (Traducción-Dr. Aurian Garcia Gonzalez).

Risk factors for sacral fracture following en bloc chordoma resection

OBJECTIVE

The purpose of this study was to analyze risk factors for sacral fracture following noninstrumented partial sacral amputation for en bloc chordoma resection.

METHODS

A multicenter retrospective chart review identified patients who underwent noninstrumented partial sacral amputation for en bloc chordoma resection with pre- and postoperative imaging. Hounsfield units (HU) were measured in the S1 level. Sacral amputation level nomenclature was based on the highest sacral level with bone removed (e.g., S1 foramen amputation at the S1-2 vestigial disc is an S2 sacral amputation). Variables collected included basic demographics, patient comorbidities, surgical approach, preoperative radiographic details, neoadjuvant and adjuvant radiation therapy, and postoperative sacral fracture data.

RESULTS

A total of 101 patients (60 men, 41 women) were included; they had an average age of 69 years, BMI of 29 kg/m2, and follow-up of 60 months. The sacral amputation level was S1 (2%), S2 (37%), S3 (44%), S4 (9%), and S5 (9%). Patients had a posterior-only approach (77%) or a combined anterior-posterior approach (23%), with 10 patients (10%) having partial sacroiliac (SI) joint resection. Twenty-seven patients (27%) suffered a postoperative sacral fracture, all occurring between 1 and 7 months after the index surgery. Multivariable logistic regression analysis demonstrated S1 or S2 sacral amputation level (p = 0.001), combined anterior-posterior approach (p = 0.0064), and low superior S1 HU (p = 0.027) to be independent predictors of sacral fracture. The fracture rate for patients with superior S1 HU < 225, 225-300, and > 300 was 38%, 15%, and 9%, respectively. An optimal superior S1 HU cutoff of 300 was found to maximize sensitivity (89%) and specificity (42%) in predicting postamputation sacral fracture. In addition, the fracture rate for patients who underwent partial SI joint resection was 100%.

CONCLUSIONS

Patients with S1 or S2 partial sacral amputations, a combined anterior-posterior surgical approach, low superior S1 HU, and partial SI joint resection are at higher risk for postoperative sacral fracture following en bloc chordoma resection and should be considered for spinopelvic instrumentation at the index procedure.

The Role of 3D Printing in Treatment Planning of Spine and Sacral Tumors

Three-dimensional (3D) printing technology has proven to have many advantages in spine and sacrum surgery. 3D printing allows the manufacturing of life-size patient-specific anatomic and pathologic models to improve preoperative understanding of patient anatomy and pathology. Additionally, virtual surgical planning using medical computer-aided design software has enabled surgeons to create patient-specific surgical plans and simulate procedures in a virtual environment. This has resulted in reduced operative times, decreased complications, and improved patient outcomes. Combined with new surgical techniques, 3D-printed custom medical devices and instruments using titanium and biocompatible resins and polyamides have allowed innovative reconstructions.

Preoperative Patient-reported Outcomes are not Associated With Sagittal and Spinopelvic Alignment in Degenerative Lumbar Spondylolisthesis

STUDY DESIGN

Prospective cohort study.

OBJECTIVE

The aim of this study was to evaluate whether sagittal and spinopelvic alignment correlate with preoperative patient-reported outcomes (PROs) in degenerative lumbar spondylolisthesis (DLS) with spinal stenosis.

SUMMARY OF BACKGROUND DATA

Positive global sagittal balance and spinopelvic malalignment are strongly correlated with symptom severity in adult spinal deformity, but this correlation has not been evaluated in DLS.

METHODS

Patients were enrolled in the Canadian Spine Outcomes Research Network (CSORN) prospective DLS study at seven centers between January 2015 and May 2018. Correlation was assessed between the following preoperative PROs: Oswestry Disability Index (ODI), numeric rating scale (NRS) leg pain, and NRS back pain and the following preoperative sagittal radiographic parameters SS, PT, PI, SVA, LL, TK, T1SPI, T9SPI, and PI-LL. Patients were further divided into groups based on spinopelvic alignment: Group 1 PI-LL<10°; Group 2 PI-LL ≥10° with PT <30°; and Group 3 PI-LL ≥10° with PT ≥30°. Preoperative PROs were compared among these three groups and were further stratified by those with SVA <50 mm and SVA ≥50 mm.

RESULTS

A total of 320 patients (61% female) with mean age of 66.1 years were included. Mean (SD) preoperative PROs were: NRS leg pain 7.4 (2.1), NRS back pain 7.1 (2.0), and ODI 45.5 (14.5). Preoperative radiographic parameters included: SVA 27.1 (33.4) mm, LL 45.7 (13.4°), PI 57.6 (11.9), and PI-LL 11.8 (14.0°). Weak but statistically significant correlations were observed between leg pain and PT (r = -0.114) and PI (ρ = -0.130), and T9SPI with back pain ( r  = 0.130). No significant differences were observed among the three groups stratified by PI-LL and PT. No significant differences in PROs were observed between patients with SVA <50 mm compared to those with SVA ≥50 mm.

CONCLUSION

Sagittal and spinopelvic malalignment do not appear to significantly influence baseline PROs in patients with DLS.

LEVEL OF EVIDENCE

Prognostic level II.

Effectiveness of Surgical Decompression in Patients With Degenerative Cervical Myelopathy: Results of the Canadian Prospective Multicenter Study

BACKGROUND

Conflicting evidence exists regarding the effectiveness of surgery for degenerative cervical myelopathy (DCM), particularly in mild DCM.

OBJECTIVE

To prospectively evaluate the impact of surgery on patient-reported outcomes in patients with mild (modified Japanese Orthopaedic Association [mJOA] ≥ 15), moderate (mJOA 12-14), and severe (mJOA < 12) DCM.

METHODS

Prospective, multicenter cohort study of patients with DCM who underwent surgery between 2015 and 2019 and completed 1-yr follow-up. Outcome measures (mJOA, Neck Disability Index [NDI], EuroQol-5D [EQ-5D], Short Form [SF-12] Physical Component Score [PCS]/Mental Component Score [MCS], numeric rating scale [NRS] neck, and arm pain) were assessed at 3 and 12 mo postoperatively and compared to baseline, stratified by DCM severity. Changes in outcome measures that were statistically significant (P < .05) and met their respective minimum clinically important differences (MCIDs) were deemed clinically meaningful. Responder analysis was performed to compare the proportion of patients between DCM severity groups who met the MCID for each outcome measure.

RESULTS

The cohort comprised 391 patients: 110 mild, 163 moderate, and 118 severe. At 12 mo after surgery, severe DCM patients experienced significant improvements in all outcome measures; moderate DCM patients improved in mJOA, NDI, EQ-5D, and PCS; mild DCM patients improved in EQ-5D and PCS. There was no significant difference between severity groups in the proportion of patients reaching MCID at 12 mo after surgery for any outcome measure, except NDI.

CONCLUSION

At 12 mo after surgery, patients with mild, moderate, and severe DCM all demonstrated improved outcomes. Severe DCM patients experienced the greatest breadth of improvement, but the proportion of patients in each severity group achieving clinically meaningful changes did not differ significantly across most outcome measures.

Is focused magnetic resonance imaging adequate for treatment decision making in acute traumatic thoracic and lumbar spine fractures seen on whole spine computed tomography?

PURPOSE

To assess whether a focused magnetic resonance imaging (MRI) limited to the region of known acute traumatic thoracic or lumbar fracture(s) would miss any clinically significant injuries that would change patient management.

STUDY DESIGN/SETTING

A multicenter retrospective clinical study.

PATIENT SAMPLE

Adult patients with acute traumatic thoracic and/or lumbar spine fracture(s).

OUTCOME MEASURES

Pathology identified on MRI (ligamentous disruption, epidural hematoma, and cord contusion), outside of the focused zone, an alteration in patient management, including surgical and nonsurgical, as a result of the identified pathology outside the focused zone.

METHODS

Records were reviewed for all adult trauma patients who presented to the emergency department between 2008 and 2016 with one or more fracture(s) of the thoracic and/or lumbar spine identified on computed tomography (CT) and who underwent MRI of the entire thoracic and lumbar spine within 10 days. Exclusion criteria were patients with >4 fractured levels, pathologic fractures, isolated transverse, and/or spinous process fractures, prior vertebral augmentation, and prior thoracic or lumbar spine instrumentation. Patients with neurologic deficits or cervical spine fractures were also included. MRIs were reviewed independently by one spine surgeon and one musculoskeletal fellowship-trained emergency radiologist for posterior ligamentous complex (PLC) integrity, vertebral injury, epidural hematoma, and cord contusion. The surgeon also commented on the clinical significance of the pathology identified outside the focused zone. All cases in which pathology was identified outside of the focused zone (three levels above and below the fractures) were independently reviewed by a second spine surgeon to determine whether the pathology was clinically significant and would alter the treatment plan.

RESULTS

In total, 126 patients with 216 fractures identified on CT were included, with a median age of 49 years. There were 81 males (64%). Sixty-two (49%) patients had isolated thoracolumbar junction injuries and 36 (29%) had injuries limited to a single fractured level. Forty-seven (37%) patients were managed operatively. PLC injury was identified by both readers in 36 (29%) patients with a percent agreement of 96% and κ coefficient of 0.91 (95% CI 0.87-0.95). Both readers independently agreed that there was no pathology identified on the complete thoracic and lumbar spine MRIs outside the focused zone in 107 (85%) patients. Injury outside the focused zone was identified by at least one reader in 19 (15%) patients. None of the readers identified PLC injury, cord edema, or noncontiguous epidural hematoma outside the focused zone. Percent agreement for outside pathology between the two readers was 92% with a κ coefficient of 0.60 (95% CI 0.48-0.72). The two spine surgeons independently agreed that none of the identified pathology outside of the focused zone altered management.

CONCLUSIONS

A focused MRI protocol of three levels above and below known thoracolumbar spine fractures would have missed radiological abnormality in 15% of patients. However, the pathology, such as vertebral body edema not appreciated on CT, was not clinically significant and did not alter patient care. Based on these findings, the investigators conclude that a focused protocol would decrease the imaging time while providing the information of the injured segment with minimal risk of missing any clinically significant injuries.

Study on physical properties of Ayurvedic nanocrystalline Tamra Bhasma by employing modern scientific tools

Background

Tamra Bhasma is derived from metallic copper that is recommended for different ailments of liver and spleen, dropsy, abdominal pain, heart disease, colitis, tumors, anemia, loss of appetite, tuberculosis, as well as eye problems.

Objectives

The knowledge of crystallite size and active ingredients in Bhasma materials is limited restricting its use as nanomedicine in the modern era. Also, the 2015 Nobel prize in medicine has motivated many researchers towards traditional medicines. Therefore, the different chemical and physical properties of prepared Tamra Bhasma has been studied by modern experimental tools (XRD, VSM, SEM, FTIR and PL spectrometer) and the preliminary testing of Tamra Bhasma nanoparticles was examined on bacteria.

Materials and methods

Bhasma is prepared by metals and minerals using three step procedures e.g. Shodhana, Bhavana and Marana. In the present work, for the preparation of Tamra Bhasma, pulverized copper wire was used and prepared by the principle of Puta (incineration) in an Electrical Muffle Furnace (EMF).

Results

X-ray diffraction analysis and scanning electron microscopy results revealed that the crystallite size of Bhasma powder was less than 100 nm and nanocrystallites of aglomerated size in micrometer. Magnetometer measurement supports its medicinal value. Photoluminescence (PL) properties of nanocrystalline Bhasma powder was investigated in UV-NIR region and shows luminescence in visible region. The antimicrobial study of Tamra Bhasma shows effectiveness on bacteria and, may be useful to control the bacterial infection disease.

Conclusion

Scientific data obtained using modern scientific tools and evidence would support in utilizing the ancient Indian wisdom of Ayurveda for the development of newer drugs as a modern nanomedicine and in other possible technological applications.

Surgical management of Gorham-Stout disease of the pelvis refractory to medical and radiation therapy

Gorham-Stout disease (GSD) is a rare condition characterized by spontaneous idiopathic bone resorption that can affect any part of the skeleton. Treatment is aimed at halting osteolysis and alleviating complications associated with bone loss. Often this can be achieved via observation and supportive management, medical treatment, and/or radiation therapy. We report a case of GSD of the pelvis that was refractory to medical and radiation therapy and was managed successfully with surgery. A 30-year-old man presented to our clinic 3 years after being diagnosed at an outside institution with GSD of the pelvis that was managed with medical treatments and radiation therapy. Despite aggressive, multimodality treatment, he was unable to ambulate without crutches and was in significant pain. The patient opted for intralesional surgery and spinopelvic fusion. Sixteen months after surgery, the patient had only mild pain and was able to ambulate with a cane. Very few cases have been reported of GSD involving the pelvis that necessitated surgical management. Significant functional impairment can occur as a result of pelvic osteolysis, and traditional management strategies focused on halting resorption may not be adequate. Surgical stabilization of the affected areas is an important treatment strategy for patients who have exhausted other options.

Lapatinib-based therapy for women with advanced/metastatic HER2 positive breast cancer

BACKGROUND

Lapatinib alone or in combination with other agents, mostly capecitabine is used for patients with advanced/metastatic HER2 positive breast cancer (HER2(+)BC) after progression on trastuzumab based therapy. Here we report our experience with lapatinib based therapy in this setting.

MATERIAL AND METHODS

67 consecutive patients received lapatinib based therapy. 58 (86.6%) received lapatinib + capecitabine (LC), 7 (10.4%) with other agents and 2 (3.0%) as single agent lapatinib. Data was collected from patients' records retrospectively.

RESULTS

Objective response to lapatinib based therapy in 64 evaluable patients was 64.0% in all patients and 64.0% in patients who received LC. Median progression free survival and overall survival were 10 and 27 months in all patients and 10 and 17 months in patients who received LC, respectively. 16 (24.0%) patients had dose delay > 1 week and/or dose reduction.

CONCLUSION

Lapatinib based therapy is an effective treatment for women with advanced/metastatic HER2(+)BC after prior exposure to trastuzumab. It yields meaningful response rates, progression free and overall survival. Some patients require dose adjustments.

What are the functional results and complications from allograft reconstruction after partial hemipelvectomy of the pubis?

BACKGROUND

In patients undergoing hemipelvectomies including resection either of a portion of the pubis or the entire pubis from the symphysis to the lateral margin of the obturator foramen while sparing the hip (so-called Dunham Type III hemipelvectomies), reconstructions typically are not performed given the preserved continuity of the weightbearing axis and the potential complications associated with reconstruction. Allograft reconstruction of the pelvic ring may, however, offer benefits for soft tissue reconstruction of the pelvic floor and hip stability, but little is known about these reconstructions.

QUESTIONS/PURPOSES

(1) What is the postoperative functional status after allograft reconstruction of Type III pelvic defects? (2) What are the rates of hernia, infection, and hip instability?

METHODS

In this case series, we reviewed all patients with Type III pelvic resections (with or without anterior acetabular wall resections) who underwent allograft reconstruction between 2005 and 2013 at one center (N = 14). During the period in question, reconstruction was the general approach used in patients undergoing these resections; during that time, three other patients were treated without reconstruction as a result of either surgeon preference or the patient choosing to not have reconstruction after a discussion of the risks and benefits. Of the 14 patients treated with reconstruction, complete followup was available at a minimum of 1 year in 11 (other than those who died before the end of the first year; median, 19 months; range 16-70 months among those surviving), one was lost to followup before a year, and two others had partial telephone or email followup. Patient demographics, disease status, functional status, and complications were recorded. For a portion of the cohort (four patients) later in the series, we used a novel technique for anterior acetabular wall reconstruction using the concave cartilaginous surface of a proximal fibula allograft; the others received either a long bone (humerus or femur) or hemipelvis graft. Seven patients died of disease; two had local recurrence, and five died of metastatic disease.

RESULTS

All patients remained ambulatory Pain at 12 months after surgery was reported as none in five, mild in two, moderate in two, and severe in one. Operative complications included infection in two, symptomatic hernia in one, hip instability in one, dislocated total hip arthroplasty on the first postoperative day in one, and graft failure in one.

CONCLUSIONS

Allograft reconstruction after Type III pelvic resections can provide functional reconstruction of the pelvic ring, pelvic floor, and, in certain patients with partial anterior acetabular resections, the resected anterior acetabulum. This has implications in preventing the occurrence of hernia and hip instability in this patient population that is classically not reconstructed, although longer-term outcomes in a larger number of patients would help to better delineate this because infection, hernia, hip instability, and graft nonunion still remain concerns with this approach. The most important unanswered question remains whether, on balance, any benefits that may accrue to these patients as the result of reconstruction are offset by a relatively high likelihood of undergoing secondary or revision surgery.

alpha-Fetoprotein levels in fullterm and very low birthweight infants

Plasma alpha-fetoprotein (alpha-FP) levels were determined in fullterm and very low birthweight (VLBW) infants in the first week of life and serially in a cohort of VLBW infants for the first 24 weeks after delivery. A rapid decline in alpha-FP levels was observed in both the fullterm and VLBW infants initially. Beyond 2 weeks of age, there was a gradual, linear decline until 6 weeks, followed by a more rapid period of decline from 6 to 16 weeks. The decline in the ensuing weeks demonstrated an asymptotic pattern. The half-life of alpha-FP was 7.5 days in the first week of life in both fullterm and preterm infants, 28.7 days from 2 to 6 weeks of life and 11.9 days from 6 to 16 weeks of life in VLBW infants.

The PGE2 vaginal film: an alternative to conventional induction in multiparae with poor cervical scores

In a study involving 50 multiparous subjects with poor cervical scores (less than or equal to 3), induction of labour by conventional amniotomy and oxytocin was compared with preinduction cervical ripening using a single administration of prostaglandin E2 (850 micrograms) in a new vaginal film formulation. Indications for elective delivery, maternal characteristics and distribution of cervical scores in the two groups were similar. Significant changes in mean cervical score were achieved within 12 hours of film insertion. In this group, 11 subjects (45.8%) established labour within 12 hours and a further 8 (33.3%) did so before 24 hours so that only 5 cases required amniotomy and oxytocin. Instrumental delivery was less in this group and none of these subjects required Caesarean section for a failure of induction. No adverse maternal or fetal side effects were observed. Convenience, ease of administration and stability of this new prostaglandin formulation make it a useful alternative to conventional induction of labour in the multiparous patient with a poor cervical score.

Preinduction cervical priming in high risk pregnancy--experience with a new sustained release PGE2 vaginal film

Experience with a new sustained release PGE2 formulation is presented. 111 high risk primiparae with very poor cervical scores (less than 3) were studied. In 59 patients, labour was induced by forewater amniotomy and I.V. oxytocin. In the remaining 52 patients, film containing 850 ug of PGE2 was inserted into the vagina to ropen the cervix 24 hours prior to induction of labour. Indications for elective delivery and maternal characteristics were similar in both groups. There were significant changes in the cervical state within 12 hours of vaginal insertion. By 24 hours, 19 patients receiving vaginal film (36.5%) had established labour of whom 13 proceeded to vaginal delivery. Significantly fewer patients in the priming group required Caesarean delivery. No untoward maternal or fetal side effects were observed. Safety, ease of administration and efficacy make this new PGE2 formulation a useful agent for priming of the very poor primiparous cervix prior to induction of high risk labour.

Plasma levels of 13,14-dihydro-15-keto PGE2 after vaginal application of a new PGE2 film

To determine the release and absorption profile of prostaglandin E2 from a new vaginal film formulation containing 850 micrograms PGE2, serial plasma levels of 13,14-dihydro-15-keto PGE2 were measured by radioimmunoassay in pregnant women between 16 and 18 weeks gestation. A control group, using placebo vaginal film was included in the study. There was a somewhat uniform increase in the plasma levels of the PGE2 metabolite, reaching peak levels between 4 and 6 hours after application of the film. The findings suggest that this drug formulation could be used clinically when slow constant release of the prostaglandin is required over a period of hours such as in pre-induction cervical ripening of term pregnancy.

Anencephaly: a retrospective analysis in Singapore. 1976 to 1980

Records of 93 cases of anencephaly from three maternity hospitals in Singapore between 1976 and 1980 were analysed. The incidence was 0.54 per 1000 births. No significant correlation between anencephaly and local seasonal conditions could be found for Singapore.

Cord plasma alpha-fetoprotein values and neonatal jaundice

Umbilical cord plasma alpha-fetoprotein (AFP) values were determined in 127 infants with hyperbilirubinemia (56 glucose-6-phosphate dehydrogenase (G-6-PD) deficient and 71 G-6-PD normal) and 136 control subjects (73 G-6-PD deficient and 63 G-6-PD normal). The mean alpha-fetoprotein value of 173 +/- 35.2 (SD) mg/L for the group of infants with hyperbilirubinemia was significantly greater than that (122 +/- 21.7 mg/L) for the control infants (P less than .001). G-6-PD status and sex did not significantly affect the alpha-fetoprotein values. Using an alpha-fetoprotein level of 130 mg/L as a "cut-off" value, the incidence of false-positive results was 25.5% and the incidence of false-negative results was 11.8%. This test can be used as a screening procedure to detect infants at high risk for hyperbilirubinemia.

Thromboxane A2 and prostacyclin levels in molar pregnancy

Plasma levels of thromboxane (TX) A2 and prostacyclin (PGI2), as measured by radioimmunoassay of their respective stable metabolites TXB2 and 6-keto PGF1 alpha, were studied in six molar pregnancies immediately before, immediately following and 24 h after evacuation of the uterus. The mean (SD) levels for TXB2 were 150 (41), 137 (32) and 125 (25) pg/ml respectively, and for 6-keto PGF1 alpha the respective values were 225 (52), 226 (127) and 213 (49) pg/ml. There was no significant difference in the levels of prostanoids between the samples taken at the various time intervals. The concentration of these prostanoids in molar intravesicular fluid was also determined. Their respective mean (SD) pg/ml values were 3682 (760) for TXB2 and 2969 (744) for 6-keto PGF1 alpha. In 15 normal pregnancies of equivalent gestation, the mean amniotic fluid levels of TXB2 and 6-keto PGF1 alpha were 34 (17) and 146 (86) pg/ml respectively. The ability of molar trophoblast to generate the prostanoids from [14C]arachidonic acid in vitro was also demonstrated. Mean (SD) values for TXB2 and 6-keto PGF1 alpha were 12.2 (2.6) and 13.2 (1.8) pg/mg protein/min, respectively. It is likely that the high concentrations of prostanoids in vesicular fluid reflect the synthesizing ability of the villus vesicles. The mole contributes little to the circulatory prostanoids possibly because its villi are deficient in blood circulation.

Epidemiologic analysis of fetal death in utero in Singapore

Records on 1777 cases of missed abortion and 1001 cases of intrauterine fetal death in three major maternity hospitals in Singapore between 1976 and 1980 were analyzed. The overall incidence of these two conditions was 10.35 and 5.82 per 1000 births, respectively. During the 5-year period, the incidence of missed abortion increased consistently, from 8.05 to 12.76 per 1000 births. In contrast, during the same period, the incidence of intrauterine fetal death declined steadily from 6.44 to 4.68 per 1000 births. Missed abortions occurred more frequently in the early part of the year, especially in the months of March, April and May. The incidence of missed abortion and its correlation with possible environmental factors are discussed.

Maternal plasma estradiol and progesterone levels during therapeutic abortion induced by 16, 16 dimethyl PGE2 p-benzaldehyde semicarbazone ester

Estradiol and progesterone levels in maternal plasma after administration of 16, 16-dimethyl-PGE2 p-benzaldehyde semicarbazone ester (16,16-PGE2) 6 hourly for abortion were studied in 27 women in the second trimester of pregnancy and in 49 patients with fetal death in utero. Basal maternal plasma levels of estradiol and progesterone measured before prostaglandin injection were significantly lower in cases of fetal death in utero than in the other subjects. After 16,16-PGE2 injection, plasma levels of estradiol and progesterone fell more rapidly and to a greater extent in cases of fetal death in utero than those with normal pregnancy at corresponding gestations; the decline of plasma estradiol levels was quicker and more marked than that of progesterone. Thus, 16,16-PGE2 appears to exert a differential effect on estradiol and progesterone biosynthesis.

A comparison of some pharmacological actions of prostaglandin E1, 6-oxo-PGE1 and PGI2

Some pharmacological actions of prostaglandin E1 (PGE1), 6-oxo-PGE1 and PGI2 have been studied. 6-oxo-PGE1 and PGE1 relaxed guinea-pig tracheal muscle in vitro and increased nasal patency in normal volunteers and in subjects with vasomotor rhinitis whereas PGI2 produced opposite effects. All three compounds produced bronchodilatation in the anaesthetised guinea-pig and relaxed human respiratory tract muscle in vitro. PGI2 was several times more potent than either 6-oxo-PGE1 or PGE1 against ADP-induced aggregation of human and baboon platelets in vitro. Intravenous 6-oxo-PGE1 in the baboon caused an ex vivo inhibition of platelet aggregation, but the EC50 was 7.7 times that of PGI2. As a vasodepressor in the baboon 6-oxo-PGE1 and PGI2 were equipotent. Thus with the exception of the vasodepressor effect, the actions of 6-oxo-PGE1 qualitatively and quantitatively resembled those of the structurally related PGE1 rather than those of PGI2.

Inhibition of platelet aggregation and antagonism of vasopressin-induced ECG changes in primates by a carboprostacyclin analogue, ZK 36374

A chemically stable carboprostacyclin analogue, ZK 36374 has been compared with two other prostacyclin derivatives with respect to ADP-induced in vitro aggregation of baboon and human platelets and ex vivo platelet aggregation in the baboon. ZK 36374 was also tested on the systemic arterial blood pressure of the baboon and against vasopressin-induced ECG changes in primates. Compared to the other two compounds, ZK 36374 displayed enhanced anti-platelet aggregating activity; there was dissociation between this property and its hypotensive potency. ZK 36374 antagonized the vasopressin-induced ECG changes. These results indicate that ZK 36374 possesses therapeutic potential in vascular disease including that affecting the coronary vessels.

Cholinoreceptors in the corpus cavernosum muscle of the human penis

Acetylcholine produced contraction, relaxation or a biphasic effect on corpus cavernosum muscle strips of human penis. These effects were antagonized by atropine but were modified by hexamethonium or tetrodotoxin suggesting the presence of excitatory and inhibitory muscarinic receptors in the human penis. Nicotine and DMPP also produced contraction or relaxation of the corpus cavernosum muscle strips. These effects were presumably indirect as they were abolished by hexamethonium and tetrodotoxin. Contractions produced by nicotine or DMPP were abolished by atropine whereas the relaxations produced by these agents were only partially blocked by atropine. Hence, the receptors mediating these relaxations are unlikely to be entirely muscarinic.

Control of gonadotrophin secretion by steroid hormones in male castrates: site of oestradiol action

Four normal healthy castrated male transsexuals who were not on hormone therapy for at least 4 months volunteered for this study. Each subject received 3 infusions at weekly intervals--the first consisting of LHRH alone, the second of LHRH and oestradiol and the third of oestradiol alone. Venous blood samples were collected at 20-minute intervals 1 hour before the start and during the whole period of infusion. Plasma concentrations of FSH, LH and oestradiol were measured by radio-immunoassay. On an average, 100 micrograms of LHRH enhanced the area under the LH secretion curve by 177% and under the FSH curve by 68%. Oestradiol had a differential effect on the endogenous secretion of LH and FSH, suppressing them by 53% and 18%, respectively. Similarly, the LHRH-stimulated release of LH was significantly inhibited to a greater extent (42%) than that of FSH (23%, P less than 0.05; paired t test). Such an observation and in the light of our acceptance of the single releasing hormone theory, suggests that the differential actions of oestradiol on the secretions of FSH and LH are due to mechanisms residing in the pituitary.

Evidence for cleavage of [26-14C]cholesterol side-chain by human foetal membranes in vitro

With a view to establish the hitherto undescribed role of cholesterol in foetal-membranous steroidogenesis, homogenates of term chorion pars reflexa and amnion pars reflexa and pars placentaris collected from 6 women after spontaneous labour at term (38 to 41 weeks gestation) were incubated with [26-14C]cholesterol. Using reverse-isotope dilution analysis, [14C]isocaproic acid was isolated and characterized. This conversion constitutes strong evidence that C-20, 22-desmolase activity, normally present in the adrenal, gonadal and placental tissues, is present in the homogenates of both membranes. The efficiency of the enzymic conversion suggests that the chorion possesses a more active desmolase system compared to that of the amnion.

Inhibition of platelet aggregation with intravenous and oral administration of a carboprostacyclin analogue, 15-cyclopentyl-omega-pentanor-5(E)-carbacyclin (ONO 41483) in man

Intravenous and oral administration of a chemically stable carboprostacyclin analogue, 15-cyclopentyl-omega-pentanor-5(E)-carbacyclin (ONO 41483), resulted in ex-vivo inhibition of ADP-induced platelet aggregation in man. The maximum tolerated intravenous dose was 2.5 ng/kg/min for 1 hour and this produced a mean of 27.1% inhibition in 3 volunteers. For oral administration the tolerated single dose was 200 microgram. At this dose, there was 56.3% inhibition of aggregation (mean of 3 results). High oral (400 microgram) and intravenous doses (5 and 10 ng/kg/min for 1 hour) of ONO 41483, which caused marked inhibition of aggregation (ranging 39-100%), was accompanied by flushing of face and extremities, headache and phlebitis. However, none of the doses tested produced significant changes in arterial blood pressure or heart rate.

A randomised comparative evaluation of the copper 7, multiload copper 250 and T copper-22OC IUDs

Two new Cu-IUDs, the TCu-22OC and Multiload Cu250, were evaluated against the Cu7 in 1,199 subjects in a randomised, multicentric trial using a common study protocol. During the 2 years following insertion, cumulative first-segment rates for total use-related terminations showed no significant differences between the 3 devices; however, the Cu7 had a significantly higher termination rate for accidental pregnancy compared to the TCu-22OC and its expulsion rate was significantly higher than the ML Cu250. The rate of accidental pregnancy was higher and the expulsion rate lower with the ML Cu250 compared to the TCu-22OC but these differences were not significant. The results are discussed in relation to IUD design and their application in family planning.

Review: significance of the inhibition by prostaglandins and cyclic GMP of oxytocinase activity in human pregnancy and labour

The uterotonic action of oxytocin has been known for many decades. This neurohypophysial hormone is thought to play a functional role in human parturition. Since 1968, prostaglandins have also been implicated in parturition. These two groups of uterotonic agents have now a recognized therapeutic role, and are widely used in the induction of labour and in fertility control. However, the mechanism of action and the interrelationship between these endogenous compounds in pregnancy are poorly understood. In this article, the role and interaction of oxytocin, oxytocinase and prostaglandins in human pregnancy and labour have been reviewed. Inhibition of oxytocinase activity by prostaglandins has been suggested as a mechanism in parturition. Possible involvement of cyclic GMP in the initiation of labour has also been discussed.

Induction of labour with prostaglandin E2 and amniotomy--a multicentre, three dose schedule study in 1533 patients

Prostaglandin E2 administered orally and combined with amniotomy was used for induction of labour at or near term in 1533 patients. The study was carried out as a collaborative project between the University Departments of Obstetrics and Gynaecology in Singapore, Medan (Indonesia) and Kuala Lumpur (Malaysia). The overall success rates for Medan, Kuala Lumpur and Singapore were 95.6%, 88.1% and 84.7% respectively.

Termination of pregnancy in cases of intrauterine fetal death, missed abortion, molar and anencephalic pregnancy with intramuscular administration of 2a 2b dihomo 15(S) 15 methyl PGF2 alpha methyl ester--a multicentre study

2a 2b dihomo 15(S) 15 methyl PGF2 alpha methyl ester (dihomo 15 me PGF2 alpha) in intramuscular doses of 0.5 mg 8 hourly was used in 631 patients with abnormal intrauterine pregnancy comprising 282 cases of intrauterine fetal death, 233 cases of missed abortion, 34 and 82 cases respectively anencephalic and molar pregnancies. The study was carried out as a collaborative project between the University Departments of Obstetrics and Gynaecology in Singapore (Singapore), Medan (Indonesia) and Kuala Lumpur (Malaysia) during the period June 1974 and November 1979. Six hundred patients (95.1%) aborted or delivered in a mean time of 11.3 hours (S.D. +/- 7.0) with an average of 1.8 injections of the prostaglandin analogue per patient. Side effects included vomiting (23.6%; mean 0.45 episodes per patient), diarrhoea (44.4%; mean 1.00 episode per patient), cold and shivering (11.9%) and pyrexia (12.4%). One patient sustained a cervical laceration which did not require repair. There were no complications.

Cigarette smoke-induced cholesterol C-20, 22-desmolase inhibition in pregnancy

In an attempt to demonstrate the physiological importance of cholesterol C-20, 22-desmolase regulation of pregnenolone formation in maternal cigarette smoking during pregnancy, the in vitro effect of cigarette smoke extract on corpus luteal and placental desmolase ability to cleave (26-14C) cholesterol to (14C) isocaproic acid, was studied. Using the reverse-isotope dilution technique, (14C) isocaproic acid was isolated and characterized. With the homogenates of corpora lutea of pregnancy (4 to 9 weeks gestation) the maximal inhibitory effect (98.3%) on desmolase efficiency became evident at equivalent of 4 cigarettes. In response to concentrations of the extract at 1/2, 1, 2 and 4 cigarette equivalents on the preparations of placentae (18 to 20 weeks gestation), a dose-dependent pattern of inhibitory effect was observed (29.1 to greater than 95.1%). These results are consistent with the interpretation that decreased supply of pregnenolone for the biosynthesis of progestational and oestrogenic hormones may be causally related to changes characteristic of cigarette-smoke induced pathologic state. It is suggested that similar studies directed towards alteration in biosynthetic capacity of steroidogenic enzymes may provide the basis for our understanding of molecular events initiated in response to the common insult.

Clinical applications of prostaglandins in Obstetrics and Gynaecology

Although a number of potential practical uses of prostaglandins have been identified, these compounds have so far found clinical applications mainly in Obstetrics and Gynaecology. It is almost 15 years since a prostaglandin was first used for the induction of term labour and prostaglandin E2 is now commercially available for this purpose in many countries. For the termination of second trimester pregnancy, prostaglandins have almost completely replaced other methods previously in use. Other areas where prostaglandins are routinely used or where their uses are being developed, include menstrual induction, preevacuation dilatation of the cervix in the first trimester, termination of pregnancy in cases of missed abortion, intrauterine fetal death and other types of abnormal pregnancies, control of post-partum haemorrhage, treatment of post-partum or post surgical urine retention and ripening of the cervix prior to induction of labour at term. In early studies, prostaglandins E2 and F2 alpha were used for all the applications listed above. In order to increase efficacy and reduce side effects, a number of synthetic analogues were later evaluated for application in selected areas. Those with modification in the 15 and 16 positions of PGE2 and PGF2 alpha molecules have undergone extensive clinical trials and some of these analogues are now in routine use. The current status of the practical applications of prostaglandins in Obstetrics and Gynaecology is reviewed.

Hydatidiform mole in Singapore

A five year retrospective analysis of 198 cases of hydatidiform mole recorded in three maternity hospitals in Singapore is presented. The incidence was 1 in 868 deliveries. The number of molar pregnancies in the first half of the year was higher than in the subsequent six months. The incidence of hydatidiform mole and its correlation with possible environmental factors is discussed.

Inhibition of platelet aggregation and reversal of vasopressin-induced ECG changes by a carboprostacyclin analogue, ONO 41483, in primates

15-cyclopentyl-omega-pentanor-5(E)-carbacyclin (ONO 41483), a chemically stable carboprostacyclin analogue, was 3.3 times less active than prostacyclin but was 2.6 times more active than carboprostacyclin in inhibiting aggregation of ADP-induced baboon platelet in vitro. On human platelets in vitro, ONO 41483 was 9.4 times less active than prostacyclin and 12.7 times more active than carboprostacyclin. ONO 41483 was 3.7 times less active than prostacyclin but was 2.2 times more active than carboprostacyclin in producing a fall in arterial blood pressure in anaesthetised baboons. Intravenous and oral administration of ONO 41483 in baboons produced ex vivo inhibition of ADP-induced platelet aggregation at doses that did not affect blood pressure or heart rate. In addition, bolus intravenous doses (3 to 10 micrograms/kg) of ONO 41483 reversed vasopressin-induced ECG changes in the monkey, suggesting an ability of the compound to relieve coronary spasm.

Research and development in obstetrics & gynaecology in the Department of Obstetrics & Gynaecology at the National University of Singapore

This is a review of the research and achievements of the Department of Obstetrics and Gynaecology, National University of Singapore since 1949. The research activities reviewed are Fertility Control, Subfertility, Reproductive Endocrinology, In-Vitro Fertilization, Trophoblastic Disease, Prostaglandins and Perinatal Medicine. The University Department has kept abreast with the Singapore norm of two-child families by providing the most sophisticated technology and expertise. The perinatal mortality and stillbirth rates have been reduced to 11 and 6 per thousand births. Prostaglandin research in the Department includes an investigation of the involvement of these substances in various physiological processes, pharmacological studies with different prostaglandins and development of clinical applications. Between 1974 and 1981 we had studied 12 intrauterine contraceptive devices, both on a departmental basis and in conjunction with international agencies. The newer medicated devices have proved to offer significant advantages over the original inert plastic configuration. Metabolic changes in Singapore women on the oral pill and injection Depoprovera were studied. Impaired glucose tolerance and raised fasting total lipids were found in women on the pill. Marginal changes in carbohydrate metabolism only were found in women on injection Depoprovera. Hypercoagulation changes in the blood occurring in Singapore women varied with the dose of the synthetic or natural oestrogen medication. Initially, the fibrinolytic activity was enough to compensate for these changes; however after two years there were signs of decompensation. Progestogens affect coagulation via their influence on the liver functions. Hypercoagulation changes also occurred in pregnancy and was of a greater magnitude than oestrogen or progestogen medication. In many obstetric disorders, including hydatidiform mole, there was evidence of intravascular coagulation. The introduction of endocrine function tests has greatly improved patient care in our Department, in particular those related to endocrine disorders. Application of the immunoassays to basic research has shown that physiological levels of oestradiol exert a negative feedback effect on both FSH and LH secretions in men. The greater suppression of LH than of FSH secretion by pharmacological doses of estradiol is possibly due to different control mechanisms in the pituitary for the synthesis and release of both gonadotrophins. Physiological level of testosterone per se has a definite negative feedback effect on the secretion of LH but not on FSH. Pharmacological doses of the 5-alpha-reduced metabolites of testosterone have been shown to suppress both LH and FSH indicating that some of the actions of testosterone could be medicated by these metabolites of which the 3 alpha-androstanediol and 3 beta-androstanediol are the more likely candidates.

Reversal of vasopressin-induced coronary vasoconstriction by a PGE1 analogue (ONO 1206) in primates

17 (S)methyl-omega-homo trans delta 2 PGE1 (ONO 1206) an analogue of PGE1 was studied on vasopressin-induced ECG changes in four male monkeys and three female baboons. Bolus intravenous doses of vasopressin (0.8 I.U. to 1.0 I.U./kg) produced flattening of the T wave (2 monkeys) elevation of ST segment (1 baboon and 1 monkey) and inversion of T wave (1 baboon). Inverted T waves were also present in one baboon and one monkey prior to any drug administration. In four out of seven animals, boLus intravenous doses (5 to 15 micrograms/kg) of ONO 1206 reversed the ECG changes produced by vasopressin and in one animal ONO 1206 reversed the existing inverted T wave. These findings indicate that vasopressin is a suitable agent for the induction of coronary vasoconstriction in primates and that ONO 1206 is able to reverse this effect.

Termination of second trimester pregnancy with laminaria and intramuscular 16 phenoxy-omega-17, 18, 19, 20 tetranor PGE2 methylsulfonylamide (sulprostone)-A randomised study

16 phenoxy-omega-17, 18, 19, 20 tetranor PGE2 methylsulfonylamide (Sulprostone) was used for termination of second trimester pregnancy in four groups of 30 patients. The drug was administered in intramuscular doses of either 0.5 mg four hourly or 1.0 mg 8 hourly. In two groups of 30 patients a medium size sterile laminaria was inserted into the cervical canal eight hours before the start of prostaglandin treatment. In the group treated with 1.0 mg sulprostone eight hourly, 96.7% of those with laminaria and 86.7% without laminaria aborted in respective mean times of 11.2 hrs and 17.5 hrs. All 30 patients (100%) in the laminaria group treated with 0.5 mg sulprostone four hourly aborted within 30 hours in a mean time of 10.4 hours compared with 26 patients (86.7%) in a mean time of 16.7 hours in the group without laminaria. One patient receiving 0.5 mg sulprostone four hourly (no laminaria) sustained a cervical tear requiring repair. The incidence of nausea, vomiting, diarrhoea, cold and shivering was low an similar in the four groups.

Elevated intravesicular fluid luteinizing hormone concentration in hydatidiform mole

Concentrations of human chorionic gonadotrophin (beta-hCG), follicle-stimulating hormone (FSH), luteinizing hormone (LH) and prolactin (PRL) were measured by radioimmunoassay in the serious fluid of hydatid vesicles obtained from 27 patients with hydatidiform mole. High amounts of all four hormones were found in every case. The mean concentrations +/- SEM were 710.8 +/- 100.8 i.u./1 X 10(-3) for beta-hCG, 13.8 +/- 0.3 i.u./1 for FSH, 302.2 +/- 34.5 i.u./1 X 10(-3) for LH and 2610.8 +/- 562.1 m-i.u./1 for PRL. It is suggested that aberrations in the mechanisms controlling the synthesis and release of luteinizing hormone-releasing factor (LH-RF) could result in chronically elevated LH levels leading to changes characteristic of the disease.

pH dependent inhibition of serum oxytocinase activity by prostaglandins and cyclic GMP

The effect of pH in the range 6.2 to 7.7 on the inhibition of serum oxytocinase (EC 3.4.11.3) activity by various compounds was studied using S-benzyl-L-cysteine-p-nitroanilide (BCN) as substrate. Prostaglandins E1, E2, F2 alpha, 8-bromo-cGMP, cGMP, indomethacin and polyphloretin phosphate (PPP) produced a dose related pH dependent inhibition of serum oxytocinase. Their effect was maximum at pH 6.2 and minimum at pH 7.7. Hypertonic urea and saline also caused pH dependent inhibition; saline being most active at pH 6.2, and urea at pH 7.7. A similar pH dependent inhibition was found when these compounds were examined for their effect on the hydrolysis of L-leucine-p-nitroanilide (LN) by serum aminopeptidases at pH between 6.2 and 7.7. Although the inhibitors were more effective against the hydrolysis of LN than BCN substrate, cGMP and its 8-bromo derivative were more active against the BCN hydrolysis. cAMP, 8-bromo-cAMP, dibutyryl (db)-cAMP, db-cGMP, AMP, ADP, ATP, GDP, GTP, aspirin, sodium salicylate, paracetamol, theophylline and isobutylmethylxanthine (IBMX) at comparable concentrations and within the same pH range had no effect on the hydrolysis of either substrate. It is concluded that in serum obtained during pregnancy, the hydrolysis of LN may largely be attributed to oxytocinase activity. Thus, inhibition of LN hydrolysis by prostaglandins and other substances may be regarded as inhibition of oxytocinase activity.

Recovery of hypophyseal-testicular function from sex steroid treatment and the pituitary response to castration in male transsexuals

Twenty-one male transsexuals who had been on steroid hormone therapy for at least 1 year volunteered for this investigation. Their hormone profiles after stopping sex steroid hormone treatment for periods ranging from 2 to 70 days were examined. Based on their testosterone levels before the sex-reassignment operation which includes castration, penectomy and the construction of an artificial vagina, two separate groups can be distinguished; those with low (group A) and the other with normal (group B) levels. The gonadotrophins levels in group A and group B were (respectively) significantly (P less than 0.05) lower and higher than corresponding levels in a group of normal males. Castration had caused elevations of FSH and LH in both groups. Although the increment rates were different, both groups attained the same maximum levels of FSH and LH. Within each group, the patterns of FSH and LH responses to castration were similar. However, differences in rates and time of significant elevation of FSH and LH were noted. These observations indicate that there is a delay between the cessation of steroid treatment and the recovery of testicular and hypophyseal functions. Testicular function seems to be altered by steroid treatment since excessive secretions of FSH and LH are needed to produce normal testosterone levels. The secretions of FSH and LH are controlled in some ways by the same mechanisms, while they, in other respects, are controlled by different factors.

Control of gonadotrophin secretion by steroid hormones in castrated male transsexuals. II. Effects of androgens alone and in combination with oestradiol on the secretions of FSH and LH

Twenty-nine infusions in twenty castrated male transsexual volunteers were carried out over a period of 7 h with subjects lying in the supine position. The effects of different doses of testosterone and its 5 alpha-reduced metabolites as well as the effect of testosterone in combination with oestradiol on gonadotrophin secretion were evaluated. Different and varying degrees of suppression of plasma levels of FSH and LH were observed. The infusions of 2.4 mg testosterone, 5 alpha-androstan-3 alpha-17 beta-diol (3 alpha-diol), 5 alpha-androstan-3 beta-17 beta-diol (3 beta-diol) but not dihydrotestosterone (DHT) caused significant suppression of LH. FSH, on the other hand was not significantly inhibited by the androgens at this rate. At higher doses all four androgens suppressed LH secretion significantly. FSH was similarly suppressed by the androgens except by DHT. A differential effect on FSH and LH secretions was noted with the combined regime of testosterone and oestradiol. The combined regime did not cause a significantly higher degree of FSH suppression compared with either 200 microgram of oestradiol or 12 mg of testosterone infused alone. The level of LH, however, was suppressed to a greater extent than either of the hormones when given alone. The inhibitory effect of testosterone demonstrated in this study could be due to the parent hormone or its 5 alpha-reduced metabolites. Pharmacological doses of testosterone could exert a greater degree of LH suppression through its conversion to oestradiol. It is likely that oestradiol and testosterone act on gonadotrophin secretion through different mechanisms and that they have an additive suppressive effect on the secretion of LH but not FSH. The potencies for the androgens to suppress gonadotrophin secretion can be ranked as: 3 alpha-diol = 3 beta-diol greater than testosterone greater than dihydrotestosterone.

Adrenoreceptors in the human penis

1. Adrenaline, noradrenaline and phenylephrine caused contraction of the corpus cavernosum muscle of the human penis. These sympathomimetic amines did not product inhibitory effects even in the presence of the alpha-adrenoreceptor blocker, phentolamine. The effect of dopamine was similar to that produced by these three sympathomimetic amines. Higher doses of isoprenaline and salbutamol also contracted this preparation. 2. Cocaine and guanethidine enhanced the motor response to adrenaline, noradrenaline and phenylephrine while the action of dopamine was blocked by these two drugs. 3. The motor response to adrenaline, noradrenaline and phenylephrine was antagonized by phentolamine and often potentiated by the beta-adrenoreceptors blocking drug, propranolol. The contractions produced by high doses of salbutamol and isoprenaline were also abolished by phentolamine. These findings indicate that the motor response to sympathomimetic amines is the result of activation of alpha-adrenoreceptors in the corpus cavernosum muscle. 4. At low doses, isoprenaline and salbutamol relaxed the corpus cavernosum muscle strip. The inhibitory action was blocked by low concentrations of the beta-adrenoreceptor antagonist, propranolol but not by practolol (beta 1-adrenoreceptor antagonist) and butoxamine (beta 2-adrenoreceptor antagonist). beta-adrenoreceptors are present in the corpus cavernosum muscle but these are unlikely to be either of the beta 1 or beta 2 type. The possible existence of a third type of beta-adrenoreceptor is suggested.