P11.09.B Chemotherapy is an efficient treatment in primary CNS MALT lymphoma

Background

Mucosae-associated lymphoid tissue (MALT) lymphomas are a rare and still poorly understood form of primary central nervous system lymphoma (PCNSL). The aim of this study was to better describe these tumors and their management, and to better appreciate their long-term prognosis after treatment.

Material and Methods

Adult immunocompetent patients with primary CNS MALT lymphoma (PCNSML) were retrospectively selected from the database on PCNSL of the Pitié-Salpêtrière Hospital. All cases had double-read for pathology.

Results

Eleven PCNSML representing 1.7% of the 662 PCNSL included in the database were selected, There were 9 women and two men, all immunocompetent. Their median age was 56 years (min 29; max 78). The median time from first symptoms to diagnosis was 13 months and the median KPS at diagnosis was 90. Location was dural in 8 cases, suggestive of meningioma in 7 cases and of subdural hematoma in 1 case, and parenchymal in 3 cases. The disease was unifocal/localized in 4 cases and multifocal/diffuse in 7 cases. In 3 cases, it was the second reading that allowed making the diagnosis. In first-line treatment, all patients received chemotherapy (CT): “systemic” CT, i.e usually used in systemic MALT lymphomas, in 7 cases (n=7) and “CNS” CT, i.e usually used in CNS lesions in 4 cases. CT was preceded by surgery in 4 cases. No patient received radiotherapy in first line. According to the IPCG (International PCNSL Collaborative Group) criteria, the overall response rate was 7/11 (64%). At latest news, 5 patients had a persistent contrast enhancement, stable without any treatment since a median of 57 months, raising the question of complete response despite persisting contrast enhancement. No patient developed neurotoxicity except for one of the 2 patients who subsequently received radiotherapy. The median follow-up was 109 months. The median progression-free survival was 78.0 months (95% CI [43.4;NA[) and the 10-year overall survival rate was 90% (95% CI [0.7;1[).

Conclusion

This series confirms the classical clinical and radiological presentation of PCNSML. Compared to the literature where the treatment was based on radiotherapy in almost two thirds of cases, the therapeutic approach presented here appears unconventional. This is the first series demonstrating that chemotherapy is an efficient treatment in PCNSML, with an excellent long-term outcome and the absence of neurotoxicity, and calling into question the relevance of the IPCG criteria for the evaluation of their therapeutic response.

Benefits, issues, and recommendations for personalized medicine in oncology in Canada

The burden of cancer for Canadian citizens and society is large. New technologies have the potential to increase the use of genetic information in clinical decision-making, furthering prevention, surveillance, and safer, more effective drug therapies for cancer patients. Personalized medicine can have different meanings to different people. The context for personalized medicine in the present paper is genetic testing, which offers the promise of refining treatment decisions for those diagnosed with chronic and life-threatening illnesses. Personalized medicine and genetic characterization of tumours can also give direction to the development of novel drugs. Genetic testing will increasingly become an essential part of clinical decision-making. In Canada, provinces are responsible for health care, and most have unique policies and programs in place to address cancer control. The result is inconsistency in access to and delivery of therapies and other interventions, beyond the differences expected because of demographic factors and clinical education. Inconsistencies arising from differences in resources, policy, and application of evidence-informed personalized cancer medicine exacerbate patient access to appropriate testing and quality care. Geographic variations in cancer incidence and mortality rates in Canada-with the Atlantic provinces and Quebec having higher rates, and British Columbia having the lowest rates-are well documented. Our purpose here is to provide an understanding of current and future applications of personalized medicine in oncology, to highlight the benefits of personalized medicine for patients, and to describe issues and opportunities for improvement in the coordination of personalized medicine in Canada. Efficient and more rapid adoption of personalized medicine in oncology in Canada could help overcome those issues and improve cancer prevention and care. That task might benefit from the creation of a National Genetics Advisory Panel that would review research and provide recommendations on tests for funding or reimbursement, guidelines, service delivery models, laboratory quality assurance, education, and communication. More has to be known about the current state of personalized cancer medicine in Canada, and strategies have to be developed to inform and improve understanding and appropriate coordination and delivery. Our hope is that the perspectives emphasized in this paper will stimulate discussion and further research to create a more informed response.

Evaluation of Bacillus subtilis and coliphage MS2 as indicators of advanced water treatment efficiency

The assessment of water treatment facilities for their efficiency using alternate indicators is of paramount importance. Current methods for assessing efficiency are limited by the specific characteristics of the microorganisms, such as their different sensitivities to disinfectants. A pilot study was carried out to compare different treatment scenarios for the future upgrade of the Sergio Cuevas Water Treatment plant (the largest in the Caribbean) in San Juan, Puerto Rico. The treatment units under investigation included a coagulation-flocculation-sedimentation unit, dual-media filters, micro-filtration units, intermediate ozone injection and contact columns as well as a biological filtration unit. The plant was challenged at different stages of treatment with Bacillus subtilis spores and MS2 coliphages in an attempt to test them as possible alternate indicators of treatment plant performance. These organisms were chosen because of their resistance to disinfection and desiccation, their low analysis costs and ease of detection. The removal of spores and coliphages by each treatment unit tested was calculated by seeding a known concentration (5-7 log10) of spores and coliphages and following the removal or disinfection rates. The seeded indicators were detected using traditional culture techniques. Ballasted clarification was shown to be highly efficient at removing 99.1% (approximately 3 log10) of the spores and 85.1% (approximately 0.86 log10) of MS2. Ozone treatment inactivated 80.37% (approximately 1.4 log10) spores and 99.95% (approximately 3.07 log10) coliphages. The coliphage inactivation rate obtained confirmed data obtained by previous studies indicating that MS2 was less resistant to ozonation than B subtilis spores. The membrane technology had the best efficiency in terms of physical removal of spores achieving over 99.9% (> 3 log10) removal. Coliphage removal mechanisms remain to be determined and will be a future focus of the study. Preliminary results indicate that aerobic spores and coliphages may be useful as indicators to determine the efficiency of different drinking water treatment technologies.

Placebo-controlled trial of 13-cis-retinoic acid activity on retinoic acid receptor-beta expression in a population at high risk: implications for chemoprevention of lung cancer

PURPOSE

To establish the incidence of abnormalities in the expression of retinoic acid receptor-beta (RARbeta) in bronchial cells and determine the capacity of 13-cis-retinoic acid (13-CRA) to correct such abnormalities.

PATIENTS AND METHODS

One hundred eighty-eight smokers had a medical indication for bronchoscopy and were studied with bronchial brushings. Bronchial brushing samples were obtained for cytology analysis and for molecular analysis. After RNA was extracted, RARbeta sequences were amplified by reverse transcriptase polymerase chain reaction and Southern blots were performed to assess RARbeta expression. Forty-four eligible individuals with diminished RARbeta expression consented to double-blind randomization to receive a placebo or 13-CRA 30 mg orally daily for 6 months. A second bronchoscopy was performed at the end of the treatment period. An analysis of variance was used to analyze changes in RARbeta expression before and after treatment.

RESULTS

The 6-month treatment course was completed by 27 patients, and results were obtained for a total of 18 patients (eight patients treated with 13-CRA and ten treated with the placebo). In the placebo group, there was no difference between the results of RARbeta expression before and after treatment (P =.43). In the 13-CRA group, there was an upregulation of RARbeta expression at the end of 13-CRA treatment (P =.001). Cytologic changes were uncommon. Toxicities were primarily of grade 1. Palatal brushings were compared with bronchial brushings in 40 smokers. A perfect correlation of the results of RARbeta expression was obtained from 27 patients.

CONCLUSION

RARbeta expression is frequently decreased in the bronchial epithelium of smokers and is upregulated at the end of 13-CRA treatment. These results support undertaking a phase III chemoprevention trial of 13-CRA treatment for lung cancer.

Developmental and genetic disorders in spermatogenesis

The most common cause of male infertility is idiopathic. Fresh insights based on genetic and molecular analysis of the human genome permit classification of formerly unexplained disorders in spermatogenesis. In this article, we review new procedures that expand diagnostic and therapeutic approaches to male infertility. Recombinant DNA technology makes it possible to detect specific chromosomal and/or genetic defects among infertile patients. The identification of genes linked to disorders in spermatogenesis and male sexual differentiation has increased exponentially in the past decade. Genetic defects leading to male factor infertility can now be explained at the molecular level, even though the germ cell profile of infertile patients is too variable to permit classification of the clinical phenotype. Increasing knowledge of genes that direct spermatogenesis provides important new information about the molecular and cellular events involved in human spermatogenesis. Molecular analysis of chromosomes and/or genes of infertile patients offers unique opportunities to uncover the aetiology of genetic disorders in spermatogenesis. Increasing numbers of cases, previously classified as idiopathic, can now be diagnosed to facilitate the treatment of infertile men. Advanced knowledge also poses ethical dilemmas, since children conceived with assisted reproductive technologies such as intracytoplasmic sperm injection (ICSI) are at risk for congenital abnormalities, unbalanced complements of chromosomes and male infertility.

Double-blind, randomized comparison of the effect of carbetocin and oxytocin on intraoperative blood loss and uterine tone of patients undergoing cesarean section

OBJECTIVES

A double-blind randomized study involving pregnant women undergoing cesarean section was conducted to compare the effectiveness of a single 100 micrograms intravenous injection of the long-acting oxytocin analog, carbetocin, with that of a standard infusion of oxytocin with respect to intraoperative blood loss. The two treatments also were compared for safety and ability to maintain adequate uterine tone.

STUDY DESIGN

The study drug was administered to 57 women during elective cesarean section after placental delivery; blood was collected until abdominal closure. Intraoperative blood loss was calculated with a sensitive colorimetric method. Position, tone of the fundus, and vital signs were assessed up to 24 hours after the operation. The need for additional uterotonic agents was recorded.

RESULTS

A single 100 micrograms intravenous injection of carbetocin was as effective as a continuous 16 hour infusion of oxytocin in controlling intraoperative blood loss after placental delivery. Mean blood loss after carbetocin administration was 29 ml less than after oxytocin administration (p = 0.3). Subset analysis deleting two patients who received oxytocic intervention in the operating room and one extreme outlier revealed a mean blood loss of 41 ml less in the carbetocin group (p = 0.14) with lower variances (p = 0.02). The percentage of patients with blood loss of 200 ml or less was greater with carbetocin (79% vs 53%; p = 0.041). Carbetocin enhanced early postpartum uterine involution. The fundus was below the umbilicus in more patients who received carbetocin at 0, 2, 3, and 24 hours on the ward (p < 0.05). There were no significant differences in uterine tone or type or amount of lochia. Additional oxytocin was used to treat three patients for postpartum hemorrhage or persistent uterine atony. All interventions were in the oxytocin group. Vital signs and hematologic values were comparable in each group, confirming similar safety profiles.

CONCLUSIONS

A single 100 micrograms intravenous injection of carbetocin is as effective and more reliable than a standard continuous infusion of oxytocin in maintaining adequate uterine tone and preventing excessive intraoperative blood loss during cesarean section after delivery of the placenta. Patients receiving carbetocin required less intervention. Carbetocin was well tolerated.

Prostaglandin E2 primes naive T cells for the production of anti-inflammatory cytokines

In addition to their capacity to induce pain, vasodilatation and fever, prostaglandins E (PGE) exert anti-inflammatory activities by inhibiting the release of pro-inflammatory cytokines by macrophages and T cells, and by increasing interleukin (IL)-10 production by macrophages. We here report that PGE2, the major arachidonic acid metabolite released by antigen-presenting cells (APC), primes naive human T cells for enhanced production of anti-inflammatory cytokines and inhibition of pro-inflammatory cytokines. Unfractionated as well as CD45RO- CD31+ sort-purified neonatal CD4 T cells acquire the capacity to produce a large spectrum of cytokines after priming with anti-CD3 and anti-CD28 monoclonal antibodies (mAb), in the absence of both APC and exogenous cytokines. PGE2 primes naive T cells in a dose-dependent fashion for production of high levels of IL-4, IL-10 and IL-13, and very low levels of IL-2, interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, and TNF-beta. PGE2 does not significantly increase IL-4 production in priming cultures, whereas it suppresses IL-2 and IFN-gamma. Addition of a neutralizing mAb to IL-4 receptor in primary cultures, supplemented or not with PGE2, prevents the development of IL-4-producing cells but does not abolish the effects of PGE2 on IL-10 and IL-13 as well as T helper (Th)1-associated cytokines. Addition of exogenous IL-2 in primary cultures does not alter the effects of PGE2 on naive T cell maturation. Thus PGE2 does not act by increasing IL-4 production in priming cultures, and its effects are partly IL-4 independent and largely IL-2 independent. Together with the recent demonstration that PGE2 suppresses IL-12 production, our results strongly suggest that this endogenously produced molecule may play a significant role in Th subset development and that its stable analogs may be considered for the treatment of Th1-mediated inflammatory diseases.

Abnormal fetal cardiac axis in the detection of intrathoracic anomalies and congenital heart disease

In a 14-month period, 409 women with singleton gestations referred for perinatal ultrasound consultation underwent evaluation of the fetal cardiac axis. Cardiac and intrathoracic anomalies were confirmed either by neonatal echocardiography or autopsy. Overall, 32 fetuses had an abnormal axis (nine, smaller axis than normal; 23, larger axis than normal). Of the 29 found to have cardiac (n = 24) or intrathoracic (n = 5) anomalies, 23 had an abnormal axis. The median cardiac axis of the normal group (44.0 degrees) was significantly smaller than that of the cardiac/intrathoracic anomaly group(60.0 degrees) (p = 0.002). The cardiac axis was independent of gestational age. The mean interobserver variation was 1.3 +/- 1.8 degrees. The sensitivity of an abnormal axis (< 28 degrees or > 59 degrees) in detecting congenital heart disease or intrathoracic anomalies was 23/29 (79.3%), with specificity of 371/380 (97.5%), positive predictive value of 23/32 (71.9%), and negative predictive value of 371/377 (98.4%). Of those with a cardiac anomaly and an abnormal axis (n = 18), five were felt to have an initial normal four-chamber view. An abnormal fetal cardiac axis, either larger or smaller than normal, is suggestive of a cardiac or intrathoracic anomaly and requires further investigation, such as fetal echocardiography. The cardiac axis should be considered with the four-chamber view in fetal ultrasound evaluation.

Efferent innervation of the rat testis

Previous assessments of the autonomic nerve supply of the male genital tract concluded that the testis received sympathetic input primarily from paraaortic ganglia, particularly the spermatic ganglion. We challenged this consensus by using retrograde axonal tracing to examine the source and distribution of efferent fibers reaching the testis of adult rats. We also used immunohistochemical methods to assess putative neurotransmitters in testicular neurons of the abdominal and pelvic ganglia. The results indicate the majority of retrogradely labeled cell profiles were localized within the major pelvic (38%) and pelvic accessory ganglia (37%), and only a few labeled cell profiles were present in the paraaortic and spermatic ganglia. Injection of FluoroGold and Fast Blue dyes into the respective right and left testis demonstrated that 17% of the neurons in pelvic ganglia were labeled when tracers were microinjected beneath the capsule of the contralateral testis. About 8% of the neurons were labeled both with FluoroGold and Fast Blue, suggesting that certain neurons can provide simultaneous input to the left and right testicles. Immunohistochemical results showed that tyrosine hydroxylase, a marker for noradrenergic fibers, was present in over 33% of the cell profiles labeled with either FluoroGold or Fast Blue. Some 27% of the fluorescent-labeled cell profiles were positive for neuropeptide Y, while 22% were immunoreactive for vasoactive intestinal polypeptide. No evidence for vasoactive intestinal polypeptide immunoreactivity was detected within the testis, but neuropeptide Y-immunoreactive fibers were present in the tunica albuginea and testicular vasculature. Catecholamine fluorescent fibers were distributed sparsely throughout the periphery of the testis in association with the capsule, vasculature, and interstitium.(ABSTRACT TRUNCATED AT 250 WORDS)

Dysfunctional uterine bleeding in adolescents

This retrospective, multicenter analysis was conducted on all adolescents admitted to three pediatric hospitals in Montreal, Quebec, Canada, over a 10-year period (1981-1991) with a primary diagnosis of dysfunctional uterine bleeding. The purpose was to assess the frequency of underlying medical disorders and their response to medical therapy. Sixty-one patient charts were identified. Newly diagnosed hematologic abnormalities were found in two patients (one with immune thrombocytopenic purpura and one with acute promyelocytic leukemia). Furthermore, all patients who were evaluated had normal factor VIII levels, partial thromboplastin times and prothrombin times. Twenty-nine percent of the patients had a past history of a significant medical problem. The mean age at presentation was 13.8 +/- 2.1 (SD) years. More than 50% of the patients had a history of irregular bleeding. Most patients (93.4%) responded to medical management. Only five (8.2%) required dilation and curettage. The history of irregular cycles, the early presentation after menarche, the infrequency of hematologic problems but high frequency of significant medical problems led us to conclude that the etiology of dysfunctional uterine bleeding in adolescence is often related to persistent immaturity of the hypothalamic-pituitary-ovarian axis. Medical therapy is highly effective in controlling such bleeding. Dilation and curettage is rarely required.

Variability of ischemia during spermatic cord torsion in the rat

Testicular torsion affects prepubertal males and causes testicular infarction and subfertility. Animal models of spermatic cord torsion have been used in an attempt to study the mechanism of testicular injury from torsion. Although standardized animal models of torsion have been proposed, their reliability in producing testicular ischemia has not been documented. Dynamic enhanced magnetic resonance imaging (MRI) of the testis was used in a rat model with surgically induced, unilateral, 720 degrees torsion to quantify the severity of ischemia. Intravenous dysprosium diethylenetriaminepentaacetic acid-bis methylamide (Dy-DTPA-BMA) was injected as a bolus followed by serial dynamic Turbo GRASS images. Region of interest (ROI) measurements were obtained within the testicular parenchyma during contrast enhancement and washout. Perfusion abnormalities ranging from minimal delay in contrast enhancement in the torqued testicle to complete absence of intraparenchymal blood flow were documented with dynamic enhanced MRI. Reperfusion scans 1 hour after surgical reduction of torsion showed normalization of testicular blood flow in all animals. Dynamic enhanced MRI appears to be a useful method of documenting the perfusion deficit arising from torsion of the testis. Standard animal models of torsion produce inconsistent results because they do not reliably reproduce testicular ischemia. The ability of MRI to quantify perfusion abnormalities in the testis may provide additional information in the evaluation of human patients with symptoms of testicular torsion.

Dynamic enhanced magnetic resonance imaging of testicular perfusion in the rat

Magnetic Resonance Imaging (MRI) has several theoretical advantages in the evaluation of spermatic cord torsion and testicular ischemia. The technique uses no ionizing radiation, has both excellent spatial and temporal resolution and, when used with an intravenous bolus of a paramagnetic contrast agent, provides a semiquantitative assessment of tissue perfusion and vascular injury. In clinical instances of testicular torsion, accurate estimates of tissue perfusion are desirable since testicular salvage is inversely related to the duration of torsion and the degree of tissue ischemia. Perfusion imaging of the rat testis was used as a model to demonstrate the potential use of MRI in the experimental and clinical analysis of disorders that affect blood flow to the testis.

Distribution of somatostatin immunoreactivity in the forebrain of the squirrel monkey: Basal ganglia and amygdala

The distribution of somatostatin immunoreactivity in the basal ganglia and amygdala of the squirrel monkey (Saimiri sciureus) was studied with specific polyclonal antibodies directed against somatostatin-28 and somatostatin-28(1-12). Both antibodies gave similar results with regard to the distribution of somatostatin-immunoreactive neuronal profiles. A moderately dense and highly heterogeneous network of somatostatin-positive fibers was observed throughout the striatum. A dorsoventral gradient of increasing immunoreactivity was noted in the striatum and the caudate nucleus was found to strain generally less intensely than the putamen. The immunoreactive fibers within the striatum were mostly thin and varicose and formed patches corresponding to the striosomes, as visualized on adjacent sections immunostained for calbindin. Although some somatostatin cell bodies rimmed the striosomes, most of the positive cells were rather uniformly scattered in the striatum. These medium-sized cells were significantly smaller in the caudate nucleus (93 microns2, S.D. = 26 microns2) than in the putamen (122 microns2, S.D. = 39 microns2), but their density was significantly higher in the caudate nucleus (29.7 cells/mm2, S.D. = 8.8 cells/mm2) than in the putamen (20.5 cells/mm2, S.D. = 7.0 cells/mm2). The nucleus accumbens stained moderately and positive cell bodies were evenly dispersed throughout this structure. In contrast, the olfactory tubercle displayed a heavily stained neuropil but positive neurons were encountered only in its polymorph layer. In the sublenticular region, dense fiber plexuses appeared in register with nonreactive cell clusters of the nucleus basalis of Meynert and of the nucleus of the anterior commissure. More caudally, a dense bundle of positive fibers was observed at the level of the ansa lenticularis, the inferior thalamic peduncle, and the adjoining bed nucleus of the stria terminalis. Several fibers contributing to this bundle were of the woolly type. Woolly fibers also coursed in the substantia innominata between the ventral aspect of the globus pallidus and the optic tract, and ascended in the internal medullary lamina separating the internal and external segments of the globus pallidus. Somatostatin-immunoreactive cell bodies were uniformly scattered throughout the substantia innominata. The various nuclei of the amygdala showed a wide range of immunoreactivity. The central nucleus was lightly reactive, whereas the intercalated masses displayed a moderate staining. A dorsoventral gradient of immunostaining was noted in the ventrolateral portion of the amygdala, the lateral nucleus being moderately to densely stained and the basal nucleus very lightly to lightly immunoreactive.(ABSTRACT TRUNCATED AT 400 WORDS)

Microvascular pressure distribution in the hamster testis

Convective transport is a critical element in the regulation of steroidogenesis and spermatogenesis in the testis. Steroid hormones are distributed to their target cells within seminiferous tubules via interstitial fluid. The movement of interstitial fluid and lymph, which transports protein hormones and many of the substrates required for spermatogenesis and steroidogenesis, is driven by capillary filtration. Despite the importance of convective transport in testicular function, however, the mechanisms regulating transvascular exchange in the testis are unknown. As a first step in understanding this process, we measured directly the microvascular hydrostatic pressure distribution in the hamster testis (pentobarbital sodium, 70 mg/kg ip). Using a servo-null transducer, intravascular pressure was measured in all vessel types accessible beneath the surface of the testis of 19 animals. Systemic arterial pressure averaged 89 +/- 2 (SE) mmHg. The most significant observations were that mean capillary pressure was extremely low (10.1 +/- 0.8 mmHg) and remarkably constant (range 8.2-13.3 mmHg), despite a 45 mmHg range in systemic mean arterial pressure among the animals observed. The maintenance of a low hydrostatic pressure in testicular capillaries may serve to sustain fluid filtration at a rate that prevents washout of essential solutes while preserving convective transport. Unfortunately, the anatomical and functional characteristics that determine this unique microvascular environment may also expose the testis to significant pathological risks. For example, the large pre- to postcapillary resistance ratio observed suggests that testicular capillaries must be highly susceptible to increases in venous pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Heparinase treatment suggests a role for the endothelial cell glycocalyx in regulation of capillary hematocrit

Physiological stimuli induce rapid and unexplained increases in the number of red blood cells within capillaries of skeletal muscle. We hypothesized that such alterations in intracapillary red cell numbers might be due to an undefined interaction between one or more components of blood and the luminal surface of the capillary. This proposition was tested by in situ microperfusion of capillaries with enzymes directed against macromolecules likely to be expressed on the surface of endothelial cells. The instantaneous fractional volume of red blood cells within a capillary (tube hematocrit) was used as an index of a capillary's response to enzyme microperfusion. Five to 8 min of perfusion with enzyme vehicle (0.25% albumin-Ringer solution) produced no significant alteration in capillary tube hematocrit. Perfusion with solutions containing heparinase raised the tube hematocrit at least twofold (P less than 0.05) without a significant change in red cell velocity. Heat-denatured heparinase and other enzymes such as neuraminidase, hyaluronidase, papain, pronase E, and clostripain had no detectable effect on the tube hematocrit (P greater than 0.05). After enzyme treatment, application of adenosine (10(-4) M) or oxygen caused brisk vasomotor responses in arterioles feeding perfused capillary units, but the usual changes in the tube hematocrit were not observed. Thus heparinase treatment results in a sustained elevation in the capillary tube hematocrit and a dissociation of the typical relationship between vasomotor changes and red cell distribution in capillaries. These findings suggest that physiological stimuli which alter the number of red blood cells within capillaries may operate by modifying interactions between plasma and one or more components on the luminal surface of capillaries.

Water availability affects reproduction in deer mice

Water restriction impaired sperm production in deer mice, a seasonally breeding mammal that encounters aperiodic droughts in its natural habitat throughout North America. Water-induced spermatogenic responses were sorted into three categories based upon epididymal sperm numbers: aspermic, oligospermic, and euspermic. Average gonadal mass was reduced after 10 wk of limited water consumption. Inter-individual variation in gonadal response to a simulated drought was similar to phenotypic differences in reproductive function in response to other environmental cues that direct annual reproductive cycles. Our findings suggest that water availability may act as a cue to suppress gametogenesis in deer mice independently from food, temperature, and day length.

Capillary Hematokrit - What Does It Mean?

The hematocrit of capillary blood bears little relation to the hematocrit of arterial blood. Capillary hematocrits are lower than arterial values, and, most importantly, the capillary hematocrit fluctuates in parallel with tissue metabolic activity and the contractile state of the arterioles. This suggests that the capillary hematocrit could be a controlled variable with a central role in the regulation of tissue oxygenation.

Microvessel hematocrit: measurement and implications for capillary oxygen transport

Microvascular preparations of the hamster cheek pouch and cremaster muscle were used to establish the relationship among three measures of red cell distribution: 1) the systemic hematocrit defined as the volume percentage of red cells sampled from a toe clip; 2) the tube hematocrit defined as the instantaneous volume fraction of red cells in a microvessel segment of measured length and diameter; and 3) the discharge hematocrit defined as the volume percentage of red cells that flowed into micropipettes inserted into microvessels. The results show the tube hematocrit is low and highly variable in the presence of a nearly constant systemic hematocrit. The discharge hematocrit, in contrast, consistently approximated systemic values in blood taken from arterioles or venules with diameters of 6-98 micron. Indeed, the mean ratio of the discharge to the systemic hematocrit did not differ from unity (P greater than 0.25). The observed similarity between the discharge and systemic hematocrit indicates that red cells are distributed uniformly across capillary networks. Differences between the absolute value and variance of the tube hematocrit compared with the discharge hematocrit imply that the anatomical volume of a microvessel can differ from the volume available to cells and plasma within a microvessel. Thus moment-to-moment variation in the tube hematocrit or capillary red cell spacing may be indicative of a change in the effective capillary flow cross section and not solely on the inflow hematocrit.

Pulsatile release of luteinizing hormone and testosterone in male ferrets

The temporal organization of LH and testosterone secretion was examined in male European ferrets. Hormone levels were measured in frequent blood samples taken via an indwelling jugular cannula from sexually mature and castrated ferrets. Intact ferrets discharge LH and testosterone in discrete pulses, but the frequency and amplitude of these pulses vary within and between individual males. The average frequency of LH pulses was 1.14 +/- 0.25 pulses/h, with an amplitude of 1.59 +/- 0.23 ng/ml in 11 ferrets. Testosterone pulse frequency and amplitude were 0.62 +/- 0.04 pulses/h and 16.96 +/- 2.5 ng/ml, respectively. The frequency, amplitude, and duration of hormone pulses were similar during the light and dark phases of the light-dark cycle. LH and testosterone peaks were temporally coupled with LH pulses preceding testosterone pulses by 10-20 min. However, not all LH pulses evoked a rise in testosterone. Frequently, trains of 2 or more LH pulses gave rise to a single testosterone pulse. Castration provoked a rapid increase in the frequency of LH pulses, and the interpulse interval became strikingly uniform within hours after orchidectomy. The amplitude of LH pulses, in contrast, increased gradually over the first 6 postcastration days and then plateaued at about 4.5 ng/ml. These findings demonstrate that LH pulses constitute functionally important signals to the testis, as evidenced by temporally related increments in testosterone secretion. Moreover, distinct differences in the development of the postcastration rise in the frequency and amplitude of LH pulses suggest that testosterone operates via multiple mechanisms to regulate LH release in the adult male. Finally, this study emphasizes the utility of the ferret as an animal model to study neural determinants of LH release in the male.

Genetic selection for reproductive photoresponsiveness in deer mice

Seasonal breeding is common in mammals, particularly in habitats outside the tropics. Climate and availability of food are the ultimate factors that usually dictate the optimal time of year for a mammal to breed; however, day length (photoperiod) often serves as the proximal cue to signal the onset or cessation of seasonal reproduction. Some individuals in some populations of deer mice are reproductively responsive to photoperiod, while other individuals in the same population are not. As shown here, selection can dramatically alter the frequency of photoresponsiveness in a laboratory population in only two generations. To our knowledge this is the first demonstration of selection for reproductive photoresponsiveness in any mammal. By implication, some wild populations of deer mice must use multiple, genetic-based reproductive strategies, and the degree to which each such strategy is exhibited must be subject to rapid change in response to both seasonally and momentarily changing climatic and dietary conditions.

Physical and metabolic correlates of sexual inactivity in aged male mice

The object of this study was to identify specific syndromes of sexual loss in aged male mice. Emphasis was placed on uncovering syndromes that involve physical as opposed to motivational deterioration. To this end, 30-mo-old CBF1 male mice were subjected to a large battery of tests, each of which was designed to detect sensory, neuromuscular, metabolic, or sexual deficits. Over 50 measures were obtained on each of 63 males. A group of 23 6-mo-old males were studied simultaneously to establish base lines of normal performance. Old males routinely showed evidence of deterioration in some tests but not in others. Some old males actually performed as well as young males in some tests, including an exhaustive test of sexual capacity. Ten nonsexual measures were significantly correlated with sexual activity. Further analyses then suggested seven distinct syndromes of reproductive loss, each with its own specific cause and unique manifestation. Six of these syndromes manifested themselves as behavioral deficits; one was related to a failure to eject sperm. Our data also suggest the possible existence of two more syndromes, but these remain to be verified more fully. Although additional syndromes undoubtedly will be found in male mice, the present testing paradigm can be exploited to isolate and study the functional bases of each of these specific facets of reproductive loss.

Photic cues induce multiple neuroendocrine adjustments in testicular function

Neuroendocrine responses were evaluated in an outbred population of deer mice (Peromyscus maniculatus nebrascensis) after exposure to an inhibitory photoperiod (8:16 light-dark) for 10 wk. Deer mice were chosen as an animal model for this study because they are typical of naturally selected species that rely on environmental factors to signal the onset or cessation of annual reproductive effort. Short photoperiods induced multiple neuroendocrine adjustments as judged by three types of spermatogenic responses: normal, intermediate, and azoospermic individuals. Plasma concentrations of luteinizing hormone and testosterone coincided with gradations in spermatogenic activity. In contrast, plasma concentrations of follicle-stimulating hormone were unaffected. Prolactin secretion was lowered in all mice exposed to short day lengths, regardless of sperm count. These results demonstrate that short photoperiods engage at least three types of neuroendocrine adjustments: 1) a suppression in luteinizing hormone and testosterone secretion accompanying spermatogenic arrest, 2) a reduction in prolactin secretion independent of changes in testicular function, and 3) a null response in gonadotrophic hormone secretion in which spermatogenesis is unimpaired by short day lengths. The neuroendocrine subsets identified in this model provide new evidence that photic cues induce three types of adjustments in pituitary-testicular function. These subsets are readily identified, and they can be easily exploited to dissect and manipulate the suite of neural, endocrine, and metabolic adaptations triggered by environmental lighting among mammals with annual reproductive strategies.

Differential effects of food restriction on pituitary-testicular function in mice

The reproductive responses of two species of wild rodents, house mice and deer mice, were evaluated following a 30% reduction in food intake for 5 wk. These animal models were chosen as prototypes of other rodent species because each employs unique functional adjustments when confronted with reduced resources in their natural habitats. Modest inanition failed to alter pituitary-testicular function in house mice; neither spermatogenesis nor plasma concentrations of luteinizing hormone (LH) and testosterone were modified. In sharp distinction, deer mice exposed to restricted food intake showed significant reductions in plasma LH and testosterone and an accompanying loss in spermatogenesis. Reduced food intake also caused pronounced shifts in the temporal organization and amount of wheel-running activity in both animal models, albeit in a dichotomous fashion. House mice exhibited the same amount of wheel-running activity throughout inanition, but the diel periodicity of locomotor behavior was shifted from the dark to the light period. Deer mice, in comparison, significantly curtailed wheel-running activity during the dark hours but ran in precise phase relationship with the light-dark cycle. Taken together, our results establish that the male reproductive system and its supporting neuroendocrine and behavioral correlates can be disrupted by modest levels of food restriction in certain animal models.

Testicular function and sexual activity in senescent mice

The steroidogenic potentials of testes from 6-mo-old and approximately 28-mo-old CB6F1 mice were compared by measuring the secretion rate of 11 steroids produced by testes perfused in vitro. Testes from 6- and 28- to 30-mo-old mice secreted similar amounts of testosterone, but marked differences in the secretion of testosterone biosynthetic intermediates were discovered. Testes of old mice produced significantly more (P less than 0.01) delta 5-steroids than young male mouse testes. The presence or absence of sexual activity among old male mice was not correlated with changes in testicular steroidogenesis or plasma steroid levels. The results suggest that selected alterations in androgen biosynthesis occur during aging, but that the decline in reproductive performance among old mice is not attributable to deficits in testicular steroidogenesis. Rather, age-associated losses in sexual activity may be mediated by disturbances in the central nervous system.

Mapping episodic fluctuations in plasma LH in orchidectomized rats

Reports of the frequency of pulsatile LH release in orchidectomized rats are surprisingly variable. Estimates of the period between LH pulses vary from 18.5 to 250 min in nine reports from six laboratories, published in 1981-1983. In these studies, blood samples were drawn at intervals ranging from 2.5 to 60 min. We examined the relationship between estimated LH pulse frequency and blood-sampling interval. Six castrated male rats were cannulated, and blood samples were drawn at 2.5-min intervals through 4 h. Plasma LH levels were determined by radioimmunoassay. Using the data obtained at 2.5-min intervals, we simulated blood-sampling intervals of 5, 7.5, 10, 12.5, and 15 min by sequentially deleting data points. The original and simulated data sets were analyzed by both the PULSAR and Cycle Detector computer programs. The results show that as the sampling interval increased from 2.5 to 15 min, the apparent period of pulsatile LH release rose steadily from about 20 min to about 100 min. We found a high, positive correlation between blood-sampling interval and the apparent period of LH pulses. Estimates of LH pulse frequency in castrated male rats vary directly with the frequency at which blood samples are taken. Sampling intervals greater than 5 min in orchidectomized rats yield an LH pulse period that is most likely exaggerated.

Orchidectomy unleashes pulsatile luteinizing hormone secretion in the rat

We charted the development of pulsatile luteinizing hormone (LH) secretion as a function of the time elapsed after removal of the testes. On seven occasions between the moment of castration and 80 days afterwards, we obtained consecutive blood samples at frequent (2.5- to 5-min) intervals from cannulated male rats. Orchidectomy increased both the amplitude and frequency of LH release within 1 day after surgery. Amplitude: From 19 h through 80 days postcastration, peak LH levels rose steadily, and LH pulses grew progressively more pronounced in nadir-to-peak amplitude. Frequency: Our findings offer new evidence establishing an increase in LH pulse frequency from less than 1 per h to 2-3 per h within 1 day after orchidectomy. Once deprived of testicular influences, the frequency of pulsatile LH discharges remained static through 80 days. The sudden onset (less than 1 day after castration) and temporal uniformity of high-frequency LH pulses demonstrate that LH release is governed by an intrinsic, 20- to 30-min neural periodicity in castrate rats. Most important, these findings imply that the testes mask or modulate the expression of an intrinsic, 20- to 30-min neural generator directing the periodic discharge of LH in the intact male rat.

Spermatogenesis is modified by food intake in mice

Spermatogenesis is generally viewed as being resistant to reduced food intake in inbred strains of adult mammals. This consensus stems from studies that have failed to place testicular responses within the context of a species' reproductive characteristics. We exposed two species of wild rodents, house mice and deer mice, to a mild but sustained food restriction (30% reduction of ad libitum consumption for 5 weeks). Reproductive adjustments made by each species to inanition were strikingly different. Food restriction failed to modify spermatogenesis in house mice, but evoked a continuum of testicular responses in deer mice ranging from normal spermatogenesis to azoospermia. These findings have several novel implications: 1) modest food restriction evokes species-specific adjustments in testicular function, and 2) intraspecific variation in spermatogenesis suggests robust individual differences in sensitivity to alterations in food intake. Taken together, our findings underscore the importance of considering the effects of food intake on male reproduction within the framework of a species' physiological and evolutionary background.

Development and characterization of a homologous radioimmunoassay for deer mouse (Peromyscus maniculatus bairdii) prolactin

A highly specific and sensitive homologous radioimmunoassay has been developed for the secreted form of prolactin from the deer mouse Peromyscus maniculatus bairdii. Peromyscus serum and pituitary homogenates displayed parallel dilution response curves, and no cross reaction was seen with either mouse prolactin, mouse growth hormone or rat prolactin. The assay was sensitive to 25 picograms per tube and the intra- and inter-assay coefficients of variation were 5 and 3.6%, respectively. In addition, we have demonstrated that Peromyscus prolactin does not show parallel displacement in a homologous radioimmunoassay utilized for measuring prolactin in the common laboratory mouse.

Control of pulsatile LH release in male rats

Distinct, short-term pulses of pituitary luteinizing hormone (LH) release are a characteristic feature of tonic LH secretion in normal rats. LH pulses are more pronounced, more frequent, and more regular in castrated rats. Using castrated rats, we sought to identify the basis of the pulsatile discharge of LH by the pituitary gland. Indwelling atrial cannulae were used to obtain frequent blood samples through 3-4 h from three cohorts of conscious, freely moving, orchidectomized male rats. Rats were (1) untreated castrates, (2) infused with ovine antiserum to LHRH or control serum, or (3) infused with a luteinizing hormone releasing hormone (LH-RH) analog, [D-pGlu1,D-Phe2, D-Trp3,6]-LH-RH. Castrates exhibited a pulsatile pattern of circulating LH levels; the mean (+/- SE) peak level of LH pulses was 640 +/- 15 ng/ml, with a mean (+/- SE) pulse period of 18.5 +/- 0.8 min. LH-RH antiserum arrested pulsatile LH secretion immediately, leaving plasma LH levels at 80-120 ng/ml. The LH-RH analog caused a similar suppression of LH release, although this effect was of a shorter duration than the suppression of LH pulses induced by LH-RH antiserum. The obliteration of LH pulses by anti-LH-RH and suppression of LH release by an LH-RH antagonist indicate that the pulsatile secretion of LH is due to corresponding stimulation of the pituitary gland by hypothalamic LH-RH. Anti-LH-RH and an LH-RH antagonist are identified as valuable probes for the experimental dissection of blood-borne signals within the rat hypothalamic-pituitary-testicular axis.

Steroid secretion by mouse testes perfused in vitro

We determined the concentration of steroids in blood plasma of CBF1 male mice and the steroidogenic potential of the mouse testis. Steroid secretion rates are based on measuring selected C18, C19, and C21 steroids in the venous effluent of testes perfused with a defined medium containing luteinizing hormone. Steroids were isolated by thin-layer and/or column chromatography and quantified by radioimmunoassay. These include pregnenolone, 17 alpha-hydroxypregnenolone, dehydroepiandrosterone, androstenediol, progesterone, 17 alpha-hydroxyprogesterone, androstenedione, testosterone, dihydrotestosterone, 3 alpha-androstanediol, and 3 beta-androstanediol. Testosterone is the primary steroid secreted by mouse testes perfused in vitro and is the chief androgen present in blood plasma. Pregnenolone, an obligatory intermediate in steroid synthesis, is converted to testosterone via two separate steroidogenic pathways in approximately equal proportions. This is unlike other species in which testosterone biosynthesis proceeds preferentially via either the delta 4 or the delta 5 pathway. Our results, taken together, provide the first comprehensive assessment of Leydig cell steroidogenic activity in the mouse, demonstrate putative enzymatic pathways subserving androgen biosynthesis, and establish the predominant steroids in the peripheral circulation of adult mice.

Somatic tissue responses of male rhesus monkeys treated with a contraceptive steroid formulation

Rhesus monkeys (Macaca mulatta) were treated with testosterone (100 micrograms/kg/day) plus estradiol (0.5 micrograms/kg/day) via subcutaneous polydimethylsiloxane (PDS; Silastic) implants for thirteen months. This steroid regimen inhibited dramatically spermatogenesis. Gross and histopathological examination of the musculoskeletal, circulatory, endocrine (excluding the testis), central nervous, gastrointestinal and respiratory systems failed to uncover any untoward effects of the long-term exposure due to the contraceptive formulation. Similarly, no remarkable effects were observed in the ionic, chemical and formed elements of blood or secondary sex structures. Failure to detect secondary complications attributed to the steroid treatment offers further justification for evaluating a contraceptive strategy based on administering naturally occurring steroids at sustained rates approximating those at which they are produced endogenously in the human male.

Contraceptive efficacy of testosterone-estradiol implants in male rhesus monkeys

Rhesus monkeys (Macaca mulatta) were treated with testosterone (100 micrograms/kg/day) plus estradiol (0.5 micrograms/kg/day) via subcutaneous polydimethylsiloxane (PDS, Silastic) implants. This treatment caused a striking reversible sterility. No pregnancies were observed in females bred to the steroid-treated males. In contrast, there was no difference in pregnancy rate of females bred to control and steroid-treated monkeys for 14 weeks, beginning 17 weeks after removal of the steroid-filled implants.

Testis function in rhesus monkeys treated with a contraceptive steroid formulation

Rhesus monkeys (Macaca mulatta) were treated with testosterone (100 micrograms/kg/day) plus estradiol (0.5 micrograms/kg/day) via subcutaneous polydimethylsiloxane (PDS;Silastic) implants for thirteen months. This steroid regimen inhibited LH but not FSH secretion by the anterior pituitary, inhibited testicular testosterone and estradiol production and drastically reduced the numbers of vigorously motile spermatozoa in the ejacula. Importantly, these effects on testis function were achieved at dosages of testosterone and estradiol which approximate the amount of these two steroids produced daily in normal rhesus males.

In vitro perfusion of isolated mouse testes: a model system for investigating testicular steroidogenesis

1. A procedure was developed to perfuse isolated mouse testes in vitro and investigate testosterone secretion. 2. The perfused testis preparation was validated by determining organ edema, glucose uptake, enzymatic and morphological indices of cellular integrity, and testosterone secretion in the absence and presence of LH and other pituitary peptides. 3. The results establish that this procedure can be exploited as a model system to investigate biochemical, physiological, and genetic aspects of steroidogenesis and Leydig cell function in the mouse, and presumably other small rodents as well.

Vasculature of the mouse, rat, and rabbit testis-epididymis

The arrangement of blood vessels serving the testis-epididymis vas investigated microscopically in the mouse, rat, and rabbit. Blood vessels were visualized by infusing liquid silicone rubber into the vessels and subsequently clearing the surrounding tissue. Comprehensive illustrations of the vasculature were prepared from three-dimensional examinations. Arterial and venous vessels serving the testis-epididymis follow similar routes in all three species. However, the arrangements and characteristics of the blood vessels demonstrate dramatic species differences. For example, arteries within the testes have tight coils in the mouse and artery-artery anastomoses in the rat. Veins form vascular pathways that connect the testis and efferent ductules in all three species but also form a connection between the testis and cauda epididymidis in the rabbit only. Testosterone concentrations were determined in blood obtained by micropuncture of selected testis-epididymal veins. The measurements establish that the highest levels of testosterone are found in testicular surface veins. Also, vas deferential veins of the rabbit had significant amounts of testosterone. Studies of the blood-vessel volumes suggested that the volumes of arteries and veins in the testis are similar, whereas venous volumes exceed arterial volumes in all of the other organs examined. The studies provide comprehensive information about the architecture and physiology of blood vessels serving the testis-epididymis in the mouse, rat, and rabbit. Each species exhibits diversity in the vasculature and testosterone content of the veins. Veins connecting the testis to the efferent ductules and cauda epididymidis may provide for the preferential delivery of testicular secretions to androgen-dependent organs before the secretions are metabolized or diluted in the systemic blood.

Endocrine responses to sexual arousal in male mice

The endocrine correlates of sexual arousal were explored in male mice. Using indwelling atrial cannulae, temporal changes in the blood levels of six hormones were monitored in sexually rested vs. sexually sated males before and during their exposure to receptive females. The vaginae of some test females were artificially occluded to assess separately the impact of intromission on hormone levels. Sexually rested males responded to receptive females with dramatic increases in their blood levels of corticosterone, epinephrine, and norepinephrine. These changes occurred independently of intromission. Blood titers of these three hormones did not change in sexually sated males when they encountered a receptive female. Both sexually sated and sexually rested males discharged LH in a reflex-like manner immediately upon perceiving a test female. PRL was released only in response to ejaculation, and FSH titers were unaffected by the presence of a female. In general, a receptive female elicits a variety of hormonal responses in a male mouse. Some hormones seem to be discharged in response to sexual arousal per se, whereas others are released with varying degrees of independence of this process. Viewed from another perspective, the present results allow the presentation of a relatively detailed scheme that temporally relates sensory input to hormonal response during the sexual interactions of male mice.

Luteinizing hormone and testosterone secretion in young and old male mice

This study documents, for the first time, the temporal pattern of luteinizing hormone (LH) release and the relationship between plasma LH concentrations and testicular androgenic responses in young and aged male mice. Both LH and testosterone were measured in the same samples of blood plasma withdrawn at frequent intervals over 9 h from awake, mobile mice through intra-atrial cannulae. The results demonstrate unequivocally that LH and testosterone are discharged into the circulation in discontinuous pulses in this important animal model. Robust episodes of LH release occur at infrequent intervals and increments of circulating LH occasion time-delayed elevations of plasma testosterone. Thus, the frequency of LH release is the major factor determining peripheral concentrations of this gonadotropins. The obvious one-to-one coupling between intermittent LH discharges and testosterone secretion has significant functional and investigative implications. The reduction in circulating testosterone concentrations observed in old male mice is a consequence of fewer LH discharges, which is due most likely to the slowing of a neural GnRH pulse generator. However, age-related declines in copulatory behavior were not associated with altered patterns of hormone secretion. Hence, we suggest that deficits in sexual behavior and episodic LH release in old males result from neural senescence rather than diminished testicular support of reproduction.