Sex differences in suicide mortality in Newfoundland and Labrador: An observational study with medical examiner data from 1997 to 2016

BACKGROUND

Globally, the suicide rate is two times higher for males than for females. Previous studies in Newfoundland and Labrador did not examine age-specific rates by sex. The objectives of this study were to determine suicide rates by sex and age group and to compare the demographic and clinical characteristics of males and females who died by suicide.

DATA AND METHODS

This observational study analyzed a routinely collected dataset based on all medical examiner-determined suicide deaths among people aged 10 years and older in Newfoundland and Labrador, Canada, between 1997 and 2016. Age-standardized and age-specific suicide rates and rate ratios were calculated based on the number of deaths during the period, and descriptive statistics were used to compare demographic and clinical characteristics between males and females.

RESULTS

The age-standardized suicide rate was 4.6 times higher among males than females and was higher for males in most age groups. Rates were highest in the young adult age groups for males (20 to 24 years) and females (35 to 39 years). Males who died by suicide were more likely to be from a rural community and to have died by firearm; females were more likely to die by self-poisoning and to have had a mental illness or substance use history.

INTERPRETATION

The results are broadly consistent with previous research, though this is the first study to report age-specific suicide rates among females across the life course in Newfoundland and Labrador. The results underscore the need to design public health and clinical interventions that account for sex differences in suicide risks.

Suicide in Newfoundland and Labrador, Canada: a time trend analysis from 1981 to 2018

BACKGROUND

The suicide rate in Canada decreased by 24% during the past four decades. However, rates vary between provinces and territories, and not all jurisdictions experienced the same changes. This study examined suicide rates over time in the province of Newfoundland and Labrador.

METHODS

We used cross-sectional surveillance data from the Canadian Vital Statistics Death Database to examine suicide rates in Newfoundland and Labrador from 1981 to 2018. We calculated annual age-standardized suicide mortality rates and used joinpoint regression to estimate the average annual percent change (AAPC) in suicide rates overall and by sex, age group, and means of suicide.

RESULTS

From 1981 to 2018, 1759 deaths by suicide were recorded among people in Newfoundland and Labrador. The age-standardized suicide mortality rate increased more than threefold over the study period, from 4.6 to 15.4 deaths per 100,000. The suicide rate was higher among males than females, and accounted for 83.1% of suicide deaths (n = 1462); the male-to-female ratio of suicide deaths was 4.9 to 1. The average annual percent change in suicide rates was higher among females than males (6.3% versus 2.0%). Age-specific suicide rates increased significantly for all age groups, except seniors (aged 65 or older); the largest increase was among youth aged 10 to 24 years old (AAPC 3.5; 95% CI, 1.6 to 5.5). The predominant means of suicide was hanging/strangulation/suffocation, which accounted for 43.8% of all deaths by suicide.

CONCLUSIONS

The suicide rate in Newfoundland and Labrador increased steadily between 1981 and 2018, which was in contrast to the national rate decline. The disparity between the provincial and national suicide rates and the variations by sex and age underscore the need for a public health approach to prevention that accounts for geographic and demographic differences in the epidemiology of suicide.

Rural family physician perspectives on communication with urban specialists: a qualitative study

OBJECTIVE

Communication is a key competency for medical education and comprehensive patient care. In rural environments, communication between rural family physicians and urban specialists is an essential pathway for clinical decision making. The aim of this study was to explore rural physicians' perspectives on communication with urban specialists during consultations and referrals.

SETTING

Newfoundland and Labrador, Canada.

PARTICIPANTS

This qualitative study involved semistructured, one-on-one interviews with rural family physicians (n=11) with varied career stages, geographical regions, and community sizes.

RESULTS

Four themes specific to communication in rural practice were identified. The themes included: (1) understanding the contexts of rural care; (2) geographical isolation and patient transfer; and (3) respectful discourse; and (4) overcoming communication challenges in referrals and consultations.

CONCLUSIONS

Communication between rural family physicians and urban specialists is a critical task in providing care for rural patients. Rural physicians see value in conveying unique aspects of rural clinical practice during communication with urban specialists, including context and the complexities of patient transfers.

The clients' perspective--do military uniform and rank impact on the therapeutic relationship between military mental health clients and clinicians

OBJECTIVE

To measure the perception of military mental health clients of the impact of wearing military uniform on the therapeutic relationship between client and clinician and to ascertain if uniform and rank is perceived as a barrier.

METHOD

A brief questionnaire was distributed to Departments of Community Mental Health to be disseminated to their mental health clients to measure their responses.

RESULTS

282 responses from mental health clients were collected over a 30 day period regarding the impact that military uniform makes to the therapeutic relationship with the clinician. 63% (n = 178) regarded uniform as negatively influencing their relationship with the clinician, 37% (n = 104) responded that it did not. 39% (n = 111) believed rank to be a barrier, whereas 61% (n = 171) did not believe it affected the relationship.

CONCLUSION

The majority of military mental health clients regard the wearing of uniform as negative to the therapeutic relationship and a significant minority have similar feelings about rank. Military mental health practitioners should consider the impact of these results on the therapeutic relationship with military patients.

Do military uniform and rank impact on the therapeutic relationship between military mental health clients and clinicians?

OBJECTIVE

to measure the perceptions of military staff of the impact of wearing military uniform on the therapeutic relationship with mental health clients.

METHOD

a brief questionnaire was distributed to all military clinicians in Departments of Community Mental Health to measure their attitudes.

RESULTS

there was a 67.9% (n=70) response rate regarding the impact of uniform on the therapeutic relationship. 20% of responses were positive, 31% negative, 37% mixed and 12% gave no answer.

CONCLUSION

there was no clear pre-existing literature on this issue. Overall, the wearing of uniform appeared to be perceived positively positive. There is a need to assess clients' points of view in future studies.

Atypical presentation of scabies among nursing home residents

BACKGROUND

Scabies epidemics are not uncommon in nursing homes. Effective treatment is enhanced by prompt clinical diagnosis and early intervention. The clinical presentation of scabies may vary in older, immunocompromised or cognitively impaired persons.

METHODS

We performed a retrospective study of all residents diagnosed with scabies in a multilevel long-term care geriatric facility. The duration of the outbreak was from May to September 2000.

RESULTS

Fifteen residents contracted scabies during the outbreak. All affected residents had predominantly truncal lesions. Twelve residents had diffuse erythematous, papulosquamous lesions. Pruritus occurred in only 5 residents. Three residents with severe dementia and notably impaired functional status failed to respond to Permethrin cream (5%). All 3 residents responded to treatment with oral Ivermectin.

CONCLUSION

Older nursing home residents with scabies may present with atypical skin lesions. Residents with cognitive impairment and restricted mobility may be treatment resistant. The diagnosis of scabies should be considered in any nursing home resident with an unexplained generalized rash. Residents with dementia and severe functional impairment that fail to respond to Permethrin cream (5%) may benefit from treatment with oral Ivermectin.

Pigmented uveal tumours in a transgenic mouse model

AIMS/BACKGROUND

The authors have developed transgenic mouse strains at the Arizona Cancer Center using a tyrosinase promoter to target expression of the mutated T24 Ha-ras gene in melanin producing cells. Histopathology and electron microscopy (EM) were performed to characterise the intraocular tumours observed phenotypically.

METHODS

Transgenic TPras mice (n = 8) and normal, age matched control mice (n = 6) were sacrificed at 3 weeks, 6 weeks, 7 weeks, 4 months, 5 months, 9 months, and 11 months. Six were processed in formalin for light microscopic examination and eight in a glutaraldehyde/formalin solution for electron microscopic examination.

RESULTS

Six of the TPras mice were found to have bilateral pigmented melanocytic/RPE proliferations of the uveal tract. The cytological characteristics of the tumours included low nuclear to cytoplasmic ratios (N:C ratios), bland nuclei, and abundant intracytoplasmic melanin. By EM two populations of cells were identified, including spindle-shaped cells with round to oval melanin granules and cuboidal cells with apically located, cigar-shaped, melanin granules, and basement membrane formation. A 3 week and an 11 month old TPras mouse had a higher grade, bilateral, melanocytic proliferation of the uveal tract which, although not metastatic, was morphologically melanoma. Cytological features included increased N:C ratios, nuclear pleomorphism, and prominent nucleoli. The uveal tract was normal in both eyes in all of the control animals.

CONCLUSION

Pigmented intraocular tumours developed in transgenic strains of mice that express a mutated Ha-ras gene in melanin producing cells. The morphology was most consistent with a melanoma in two of the mice and a benign melanocytic/RPE proliferation in the remaining mice.

Prevalence and causes of undernutrition in medical outpatients

PURPOSE

To assess the prevalence, common causes, and frequency of recognition and treatment of undernutrition in older and younger medical outpatients using a cross-sectional survey design with 2-year follow-up of undernourished subjects.

PATIENTS AND METHODS

Charts of 1017 adult patients attending a hospital outpatient department were reviewed for the presence of undernutrition, and 85 patients meeting inclusion criteria for undernutrition were evaluated and followed for 2 years. An initial evaluation focused on nutritional, cognitive, and affective status and on nutritional attitudes using two subscales of the EAT-26 eating disorder inventory. After 2 years, initial data plus outpatient records were evaluated by 2 independent reviewers to determine a primary cause of undernutrition and to assess the recognition and treatment of undernutrition by the primary physician.

RESULTS

Undernutrition was identified in 46 (11%) and 44 (7%) of older and younger subjects respectively; odds ratio (OR) (95% [confidence interval (CI)]) for older versus younger=1.65 (1.06 to 2.51). The primary cause of undernutrition differed between age groups but was deemed treatable in nearly 90% of all subjects. Undernutrition was recognized in 19 (43%) older subjects and 5 (12%) younger subjects (OR=5.47 [1.87 to 16.0]), and appropriate intervention(s) were instituted in 6 (14%) and 2 (5%) of older and younger subjects, respectively (OR=3.08 [0.668 to 14.21]). Older subjects scored higher on the EAT-26 oral control subscale than did younger subjects (4.7 versus 2.5, P=0.004) but similarly on the EAT-26 dieting subscale (5.2 versus 6.3, P=0.332); these relationships did not change with control for potentially confounding variables.

CONCLUSIONS

In this study, undernutrition was relatively common, usually amenable to treatment, but frequently undetected and undertreated in both older and younger medical outpatients. Older undernourished subjects exhibited higher oral control needs than younger persons, which may have implications for the pathophysiology and treatment of their malnutrition. Further improvement in detection and intervention is warranted in both younger and older age groups.

Fine-needle aspiration cytology of pleuropulmonary blastoma: case report and review of the literature

This report describes the fine-needle aspiration (FNA) cytology of a case of pleuropulmonary blastoma in a 3-yr-9-mo-old male. Pleuropulmonary blastoma is considered by most authors to be distinct from pulmonary blastoma and is a rare malignant tumor of the intrathoracic cavity. FNA smears were cellular with numerous small ovoid to spindled cells with oval to elliptical nuclei exhibiting finely granular chromatin and inconspicuous nucleoli. The cytoplasm was scant and eosinophilic with indistinct borders. Focal chondroid material and blastema-like cells were noted. The differential diagnosis suggested by the cytologic findings included rhabdomysosarcoma, teratoma, neuroblastoma, malignant mesenchymoma, pleuropulmonary blastoma, and metastatic tumor. To our knowledge, this is the first report of the cytology of this tumor.

Left atrial myxomas--a case report

A 49-year-old woman presented with symptoms of congestive cardiac failure. Cardiac auscultation revealed a crunching sound difficult to characterise in addition to a pansystolic murmur maximally audible in the 4th left intercostal space. The ausculatory findings varied from day to day but were unaffected by posture or exercise. A clinical impression of left atrial myxoma was confirmed by two dimensional echocardiography which revealed a well circumscribed mass almost completely filling the left atrium with a pedicle attached to the interatrial septum. The patient's cardiac failure improved with conservative management using frusemide and digoxin. The patient, however, refused cardiac surgery which is the definitive management of this disease.

Analysis of GPT activity in mammalian cells with a chromosomally integrated shuttle vector containing altered gpt genes

The molecular mechanisms of reversion in mammalian cells were studied utilizing the pZipGptNeo shuttle vector, with the bacterial gpt gene in the vector integrated into the chromosomal DNA of mouse cells. From mutant cell lines containing gpt genes with single base changes, revertants were selected for the reappearance of GPT activity. The copy number and expression of the gpt genes in such revertants were analyzed, and the GPT activity encoded by revertant genes in both mammalian cells and bacteria characterized. Revertants with wild-type amino acid sequence had, on average, the highest levels of GPT activity. Revertants with amino acid sequences different from the original mutants but not corresponding to wild-type had, on average, approximately half the level of GPT activity as wild-type revertants. Revertants that still contained the original mutation in the gpt gene had even lower levels of activity. These revertants were found to have amplified mutant gpt genes, which, when transferred into bacteria, were seen to encode for GPT polypeptides with partial enzymatic activity. A revertant in which the original mutation that destroyed the AUG translational start codon was retained but in which there was a secondary mutation upstream of the start codon also was characterized. The second mutation generated an in-frame CUG codon that apparently functioned as an alternative, upstream translational start codon.

A search for anomalies in the zeta, alpha, beta, and gamma globin gene arrangements in normal black, Italian, Turkish, and Spanish newborns

Globin gene mapping analyses of DNA from numerous Black babies, and from newborns from Sardinia, Sicily, Turkey, and Spain have identified the following: A high incidence of alpha-thalassemia-2 heterozygotes among Black babies with less than 1% Hb Bart's at birth and a high incidence of alpha-thalassemia-2 among Sardinians, but not among Sicilian, Turkish, and Spanish babies. A relatively high incidence of zeta-thalassemia was present among Black babies only, while triplicated zeta was seen in four of the five populations. Two Black babies were each found to have a different theta 1 deletion; two Sardinian babies had a newly discovered approximately 2.5 kb deletion between zeta and psi zeta; four babies had the rare Bgl II polymorphism between psi zeta and psi alpha; and one Black baby lacked the Eco RI site 3' to zeta. Quantitation of the zeta chain by reversed phase high performance liquid chromatography showed that two-thirds of the babies with four alpha genes (alpha alpha/alpha alpha) had levels between 0.1 and 1.0%, while nearly 90% of the babies with -alpha/alpha alpha had similar levels (averaging 0.2% for alpha alpha/alpha alpha; 0.35% for -alpha/alpha alpha; 0.75% for -alpha/-alpha). Additional data indicated that the occurrence and level of zeta are related to the level of beta, i.e. the gestational age. The presence of a zeta triplication did not affect the level of zeta in cord blood. The extensive search for gamma-globin gene anomalies resulted in the discovery of a chromosome with five gamma genes. gamma-Thalassemia was rare in all populations, while the -G gamma-G gamma- gene arrangement was mainly observed among Black babies; this arrangement is primarily responsible for high G gamma levels in cord blood samples. The strong correlation between the presence or absence of a C----T mutation at position -158 (measured in Xmn I digests) and the level of G gamma was confirmed for adult blood samples. A search for possible anomalies in the -delta-beta- region through gene mapping with Eco RV gave negative results except for the discovery of a polymorphic site 5' to delta in one of the 371 Black babies tested.

Effects of vasoactive intestinal peptide on canine prostatic contraction and secretion

Vasoactive intestinal peptide (VIP)-like immunoreactivity was found in intrinsic autonomic ganglion cells and nerve fibers located at the surface and within the canine prostate. In anesthetized dogs, porcine VIP (100-3,000 ng/kg iv) decreased arterial pressure and increased heart rate but did not result in the release of fluid from the prostate, indicating that VIP neither contracted glandular smooth muscle to expel fluid nor provoked secretion. Intravenous infusions of VIP at 10, 50, 100, and/or 200 ng X kg-1 X min-1 produced dose-related decreases in arterial pressure, increases in heart rate, and potentiation of the secretory response to the intravenous administration of pilocarpine and to electrical stimulation of the hypogastric nerves at 2 but not at 20 Hz. VIP at 1 microgram/ml neither contracted isolated strips of prostate nor modified their contraction by norepinephrine. It is unlikely that VIP mediates hypogastric nerve-induced prostatic contraction or secretion in the dog, but VIP may serve as a neuromodulator of nerve-induced secretion.

Cerebrovascular status of severe closed head injured patients following passive position changes

Nursing care of the severe closed head injured patient has two primary goals: (1) the prevention of secondary brain injury associated with intracranial hypertension, and (2) the prevention of complications associated with immobility. This study examined the effects of six body position changes, performed as part of routine nursing care interventions, on the cerebrovascular status of 18 severely head injured patients. These changes included turning and positioning in bed, head rotation, range of motion exercises, and raising and lowering of the head of the bed. All subjects had baseline mean intracranial pressures of less than or equal to 15 mm/Hg, and cerebral perfusion pressures of greater than or equal to 50 mm/Hg. Over 200 observations of the effects of position changes on heart rate (HR), mean arterial blood pressure (MABP), mean intracranial pressure (MICP), and cerebral perfusion pressure (CPP) were recorded and analyzed. With the exception of the intervention raising the head of the bed, all position changes produced increases in HR, MABP, MICP, and CPP. Typically, the physiologic changes were transient and showed recovery toward baseline values in one-minute postintervention measurements. The results of this study suggest that passive position changes may be performed safely upon severe closed head injured patients with baseline MICPs less than or equal to 15 mm/Hg, provided CPPs are maintained above 50 mm/Hg throughout each position change and provided multiple fractures do not preclude these position changes.

Urea movement across erythrocyte membrane during artificial kidney treatment

Previous work by other investigators indicates that erythrocyte urea and creatinine in uremic whole blood leaving the hemodialyzer do not move down the concentration gradients established by loss of these solutes across the dialyzer membrane. This puzzling disequilibrium is at odds with work indicating ready movement of both solutes across the erythrocyte membrane of nonuremic erythrocytes studied in vitro. The present study shows that contact with the dialyzer does not noticeably alter the erythrocyte membrane of the uremic patient, so that urea distribution between plasma and erythrocyte water is the same as that in the blood of normal control subjects. Furthermore, urea does not show a disequilibrium in concentration across the erythrocyte membrane in response to 50% dilution with a modified Ringer's solution but rather equilibrates swiftly and completely.

Nycterohemeral difference in inhibition of stress-induced ACTH in adrenalectomized rats

To determine the interactions among the determinants of ACTH secretion, we examined the influence of circadian rhythmicity on glucocorticoid suppression of ACTH. Adrenalectomized rats were injected with the same amount of corticosterone at 0900 and 1800 h, and plasma ACTH concentrations were determined under basal conditions and after a standard ether stress. At 0900 h, corticosterone suppressed both basal and stress-induced plasma ACTH concentrations. At 1800 h, the same treatment suppressed basal ACTH secretion but not the stress-induced rise. Although the same amount of corticosterone was injected at both times of day, the plasma corticosterone concentration 5 min after injection was higher at 1800 h than at 0900 h. This study indicates that there is a nycterohemeral difference in feedback suppression of stress-induced ACTH secretion by a given dose of corticosterone. The daily variation in feedback inhibition may be due to the additive effect of the evening surge stimulus and the stress stimulus that together override the feedback signal.

Hippocampal inhibition of pituitary-adrenocortical function in female rats

To assess the influence of the hippocampus on ACTH secretion, plasma ACTH concentrations were compared in hippocampectomized and control rats under conditions of differing plasma corticosterone concentrations. In the PM, hippocampectomized rats had higher basal and 2-min ether-stress-induced ACTH concentrations than did cortex-removed controls. Basal PM plasma corticosterone concentrations were also significantly elevated in the hippocampectomized group. In the AM, there were no between-group differences. Adrenalectomy abolished the PM differences between cortical-control and hippocampectomized rats. PM hypersecretion of ACTH in the absence of the hippocampus suggests that this structure contributes an inhibitory component to the neural mechanisms regulating ACTH release. The fact that this increase in hormone concentrations is limited to the PM indicates that there is a circadian variation in hippocampal action.

The effect of the expulsion phase of Trichinella spiralis on Hymenolepis diminuta infection in rats

The effect of the intestinal changes brought about by the expulsion of Trichinella spiralis in rats was studied in relation to the growth and survival of a concurrent infection with Hymenolepis diminuta, a cestode not normally rejected by the rat in low-level infections. Growth of H. diminuta was stunted in rats given T. spiralis just before, or after, infection with H. diminuta, the stunting being more pronounced when the cestode was given closer to the period of inflammation. There was no loss of the cestode from dual-infected rats and no evidence for destrobilation was found. Lower T. spiralis burdens had a correspondingly weaker effect on growth of H. diminuta, and stunting was abolished by administration of the anti-inflammatory drug cortisone acetate. It is concluded that the stunting of H. diminuta is probably due to the non-specific inflammatory component of the rat's response to T. spiralis infection.

T and B cells in the transfer of immunity against Trichinella spiralis in mice

Enriched populations of T or B cells, prepared by nylon wool filtration of mesenteric node lymphocytes from mice infected with Trichinella spiralis, were capable of transferring immunity to normal and irradiated syngeneic mice. In cell recipients there was an early loss of fecundity by the worms and an accelerated expulsion from the intestine. Treatment with anti-Thy 1.2 serum, to deplete contaminating T cells, severely reduced or abolished the protective activity of enriched B-cell fractions. Replacement of contaminating T cells by normal T cells restored the capacity of B-cell fractions to reduce worm fecundity but did not result in worm expulsion. As it was shown that comparatively small numbers of T cells (3 x 10(6)) alone were effective in transferring immunity to irradiated mice it is suggested that the T cells act not as helper cells, but are involved in the generation of changes in the intestinal environment that are detrimental to worm survival.

Transplantation of adult Trichinella spiralis between hosts: worm survival and immunological characteristics of the host--parasite relationship

A technique for the transplantation of Trichinella spiralis worms directly into the host intestine is described. Infections established by the direct transfer of adult worms were essentially normal both in terms of their survival and reproduction and in their stimulation of, and susceptibility to, host immune responses. Worms transplanted from NIH mouse donors at intervals after infection had an equal ability to survive in the recipient, even when taken from the donor shortly before or during the process of worm expulsion, showing that expulsion does not require worms to be irreversibly damaged. It was noted, however, that after 7 days in the donor the ability of the worm to reproduce in the recipient was temporarily impaired.

The effect of concurrent infection with Trichinella spiralis on Hymenolepis microstoma in mice

The intestinal changes brought about by rejection of Trichinella spiralis from mice were studied in relation to their effects on a concurrent infection with Hymenolepis microstoma, a cestode not normally rejected from mice. The rejection phase of T. spiralis was associated with a marked stunting of growth of H. microstoma given just before, during, or just after rejection of the nematode. The survival of H. microstoma was affected only when rejection of T. spiralis coincided with the intestinal phase of the cestode: if T. spiralis rejection was timed to occur after the scolex of the cestode had entered the bile duct there was no loss of H. microstoma. It is suggested that the adverse effects on growth and establishment of H. microstoma were due to the non-specific inflammatory component of the host's response to infection with T. spiralis.

Transfer of immunity to Trichinella spiralis in the mouse with mesenteric lymph node cells: time of appearance of effective cells in donors and expression of immunity in recipients

Cells capable of transferring immunity to Trichinella spiralis, i.e. of accelerating adult worm expulsion, were present in the mesenteric lymph nodes of mice infected for 4, 6 or 8 days, but not in mice infected for only 2 days. The time-course of worm expulsion in mice infected on the day of transfer was similar in recipients of day 4 or day 8 cells, expulsion becoming marked only when the recipients had been infected for at least 6 days. Transfer of cells 4 or 6 days after infection did not result in an accelerated worm expulsion; transfer 1 or 2 weeks before infection did not enhance the level of immunity in recipient mice. In contrast to the results obtained with mesenteric lymph node cells (MLNC) on immunity was transferred when recipients were given spleen cells taken from donors infected for 8 days. It is suggested that MLNC do not cause worm expulsion directly, but cooperate with another component of the host's defence mechanism. Accelerated expulsion in recipients of cells was accompanied by a premature decline in fecundity of female worms. Evidence is presented to show that worm expulsion and impaired reproduction may represent independent aspects of the immune response to T. spiralis.

Evidence for the involvement of a bone marrow-derived cell population in the immune expulsion of Trichinella spiralis

When mice were irradiated immediately before infection with Trichinella spiralis there was a profound and long-lasting interference with their ability to expel adult worms from the intestine. Irradiation given after the fifth day of infection was progressively less effective in this respect. The ability to expel worms was not restored when mesenteric lymph node cells (MLNC) were transferred (a) on the day of infection in mice irradiated one day previously, or (b) on day 7 of an infection in mice irradiated on day 6, even though the MLNC transferred immunity to intact recipients. Transfer of bone marrow (BM) alone was also without effect. However, worm expulsion was restored if, following irradiation and injection of BM, 10 days were allowed for BM differentiation before transfer of MLNC. This restoration was effective even after lethal levels of irradiation and was clearly dependent upon a donor-derived BM component cooperating with, or responding to, the activity of the transferred MLNC. The possibility that the BM component is non-lymphoid in nature is discussed.

Evidence for a free-running circadian rhythm in pituitary-adrenal function in blinded adult female rats

To study the eyes' role in maintaining the circadian rhythm in pituitary-adrenal function, 24-h patterns of corticosterone levels were compared in intact and blinded adult female rats. Rats were blinded by optic enucleation at approximately 80 days of age. Nonstress plasma corticosterone levels were determined fluorometrically in serial blood samples obtained from a tail vein at 4-h intervals for 44-h periods, 3 and 10 weeks after surgery. At 3 weeks after surgery, blinded and intact rats demonstrated comparable rhythms in corticosterone levels. At 10 weeks, steroid fluctuations in individual blinded rats still had an approximate 24-h periodicity. However, these fluctuations were no longer synchronized with the light-dark cycle or with those of other rats. These findings suggest that rats blinded as adults have a free-running pituitary-adrenal circadian rhythm.

Absence of a circadian rhythm in persisting corticosterone fluctuations following surgical isolation of the medial basal hypothalamus

To determine whether the circadian rhythm in pituitary-adrenal function is abolished after interruption of neural connections of the medial basal hypothalamus (MBH), corticosterone patterns were examined in individual adult female rats following surgical isolation of the MBH (MBHI rats). Non-stress plasma corticosterone levels were assessed fluorometrically in blood samples obtained from a tail vein of each rat at 4-h intervals for 44 h, 7-8 weeks after surgery. The highest corticosterone levels for most intact and sham-operated controls were obtained in samples collected at the period of light-dark transition. Individual MBHI rats demonstrated steroid excursions of normal amplitude that were not linked with time of day; these patterns appeared asynchronous and devoid of a 24-h cycle. The data indicate that major excursions in plasma corticosterone levels persist following surgical interruption of connections of the MBH, but circadian rhythmicity is abolished.

A9145, a new adenine-containing antifungal antibiotic: fermentation

A9145 is a basic, water-soluble, antifungal antibiotic which is produced in a complex organic medium by Streptomyces griseolus. The metabolite has a molecular weight of 510, and contains adenine as well as sugar hydroxyl and amino groups. Although glucose, fructose, glucose polymers, and some long-chain fatty acid methyl esters supported biosynthesis, oils were superior, with cottonseed oil being preferred. Several ions and salts, especially Co(2+), PO(4) (3-), and CaCO(3), were stimulatory. Adenine, nucleosides, and some amino acids increased the accumulation of A9145 in shaken-flask fermentors. Enrichment of the culture medium with tyrosine afforded maximal enhancement of antibiotic production in both flask and tank fermentors. Control of the dissolved O(2) level was also critical, the optimal concentration being 3 x 10(-2) to 4.5 x 10(-2) mumole of O(2)/ml. Optimization of various fermentation parameters increased antibiotic titers approximately 135-fold in shaken flask fermentors and 225-fold in stirred vessels.