Management of bone metastasis and cancer treatment-induced bone loss during the COVID-19 pandemic: An international perspective and recommendations

Optimum management of patients with cancer during the COVID-19 pandemic has proved extremely challenging. Patients, clinicians and hospital authorities have had to balance the risks to patients of attending hospital, many of whom are especially vulnerable, with the risks of delaying or modifying cancer treatment. Those whose care has been significantly impacted include patients suffering from the effects of cancer on bone, where delivering the usual standard of care for bone support has often not been possible and clinicians have been forced to seek alternative options for adequate management. At a virtual meeting of the Cancer and Bone Society in July 2020, an expert group shared experiences and solutions to this challenge, following which a questionnaire was sent internationally to the symposium's participants, to explore the issues faced and solutions offered. 70 respondents, from 9 countries (majority USA, 39%, followed by UK, 19%) included 50 clinicians, spread across a diverse range of specialties (but with a high proportion, 64%, of medical oncologists) and 20 who classified themselves as non-clinical (solely lab-based). Spread of clinician specialty across tumour types was breast (65%), prostate (27%), followed by renal, myeloma and melanoma. Analysis showed that management of metastatic bone disease in all solid tumour types and myeloma, adjuvant bisphosphonate breast cancer therapy and cancer treatment induced bone loss, was substantially impacted. Respondents reported delays to routine CT scans (58%), standard bone scans (48%) and MRI scans (46%), though emergency scans were less affected. Delays in palliative radiotherapy for bone pain were reported by 31% of respondents with treatments often involving only a single dose without fractionation. Delays to, or cancellation of, prophylactic surgery for bone pain were reported by 35% of respondents. Access to treatments with intravenous bisphosphonates and subcutaneous denosumab was a major problem, mitigated by provision of drug administration at home or in a local clinic, reduced frequency of administration or switching to oral bisphosphonates taken at home. The questionnaire also revealed damaging delays or complete stopping of both clinical and laboratory research. In addition to an analysis of the questionnaire, this paper presents a rationale and recommendations for adaptation of the normal guidelines for protection of bone health during the pandemic.

Risk of recurrent stillbirth: a cohort study

OBJECTIVES

To evaluate the recurrence risk of stillbirth.

DESIGN

Retrospective cohort study.

SETTING AND POPULATION

All births 1992-2017, Alberta, Canada.

METHODS

Retrospective cohort study.

MAIN OUTCOME MEASURES

Stillbirth was defined as the death in utero of a fetus with gestational age ≥20 weeks or weighing ≥500 g. Stillbirths were further subdivided into those occurring before labour and those in labour.

RESULTS

We identified 744 897 births from 308 478 women. Of these, 3698 women experienced a stillbirth and, of these, 97.7%, experienced only one. For women with a small-for-gestational- age stillbirth in the first birth, their risk of a subsequent antepartum stillbirth was increased substantially: 4.09%, relative risk (RR) 10.39, 95% CI 5.81-18.59. For women with a first birth appropriate-for-gestational-age stillbirth with no risk factors such as pregnancy induced hypertension, the risk with pre-existing diabetes mellitus or hypertension was also increased but to a much lesser degree (RR 2.46, 95% CI 1.23-4.91). For women who had experienced a first birth intrapartum stillbirth, the risk of another intrapartum stillbirth was very high (3.59%, RR 36.50, 95% CI 20.17-66.05). Most of these births also occurred prior to 24 weeks' gestation: 83% (10/12).

CONCLUSIONS

The risk of recurrent antepartum stillbirth is low. The increase in risk in instances where the antepartum stillbirth was not growth-restricted is not clinically meaningful. Given the very low risk in any given gestational week, fetal surveillance is unlikely to be effective and may lead to unnecessary interventions. Intrapartum stillbirth has a very high recurrence risk but may not be preventable.

TWEETABLE ABSTRACT

Stillbirth recurrence is rare.

Vaccination protects rats from methamphetamine-induced impairment of behavioral responding for food

(+)-Methamphetamine (METH) addiction is a chronic disease that interferes with fundamental brain-mediated behaviors and biological functions like eating. These studies present preclinical efficacy and safety profiles for a METH conjugate vaccine (IC(KLH)-SMO9) designed to treat METH abuse. ICKLH-SMO9 efficacy and safety were assessed over a 16-week period by monitoring general health and stability of responding in a food maintained behavioral paradigm. Male Sprague-Dawley rats were trained to lever press for food reinforcers until stable behavior was established. Rats (n=9/group) were then immunized with 100 μg of a control antigenic carrier protein (IC(KLH)-Cys) or IC(KLH)-SMO9 in Alhydrogel adjuvant, with booster immunizations at 4, 8 and 12 weeks. Health, immunization site and behavior were assessed daily. No adverse effects were found. During weeks 14-16, when antibody titers and METH affinity (K(d)=13.9 ± 1.7 nM) were maximal, all rats received progressively higher METH doses (0.3-3.0 mg/kg) every 3-4 days, followed by behavioral testing. Even though the lower METH doses from 0.3 to 1.0 mg/kg produced no impairment in food maintained behavior, 3.0-mg/kg in control rats showed significantly (p<0.05) reduced response rates and number of reinforcers earned, as well as reduced food intake. In sharp contrast, the IC(KLH)-SMO9 group showed no changes in food maintained behavior at any METH dose, even though METH serum concentrations showed profound increases due to anti-METH antibody binding. These findings suggest the IC(KLH)-SMO9 vaccine is effective and safe at reducing adverse METH-induced effects, even at high METH doses.

The risk of unexplained antepartum stillbirth in second pregnancies following caesarean section in the first pregnancy

OBJECTIVE

To determine if a previous caesarean section increases the risk of unexplained antepartum stillbirth in second pregnancies.

STUDY DESIGN

Retrospective cohort study.

SETTING

Large Canadian perinatal database.

POPULATION

158 502 second births.

METHODS

Data were obtained from a large perinatal database, which supplied data on demographics, pregnancy complications, maternal medical conditions, previous caesarean section and pregnancy outcomes.

MAIN OUTCOME MEASURES

Total and unexplained stillbirth.

RESULTS

The antepartum stillbirth rate was 3.0/1000 in the previous caesarean section group compared with 2.7/1000 in the previous vaginal delivery group (P= 0.46). Multivariate logistic regression modelling, including terms for maternal age (polynomial), weight >91 kg, smoking during pregnancy, pre-pregnancy hypertension and diabetes, did not document an association between previous caesarean section and unexplained antepartum stillbirth (OR 1.27, 95% CI 0.92-1.77).

CONCLUSION

Caesarean section in the first birth does not increase the risk of unexplained antepartum stillbirth in second pregnancies.

Response to intensity of reproduction in mouse lines resistant or susceptible to fescue toxicosis

Our objective was to examine whether mouse lines divergently selected for response to fescue toxicosis differed in the impact of increasing reproductive intensity on growth, final weight or first and second parity reproduction. Resistant (R) and susceptible (S) females were never mated (NR), mated only once (low reproduction, LR), mated after their first litter was weaned (moderate reproduction, MR) or paired continuously with a male (high reproduction, HR), allowing concurrent pregnancy and lactation. Final weight was significantly higher in mated than in not mated females (31.6 +/- 0.6, 35.9 +/- 0.6, 36.8 +/- 0.6 and 37.2 +/- 0.5 g for NR, LR, MR and HR females respectively), but the effect of increasing reproductive intensity was similar in both lines. Neither genetic line, reproductive treatment (LR and MR versus HR) nor their interaction affected first parity traits of dams or pups. In second parity, S dams produced larger litters at birth and weaning and heavier litters at birth than R dams, and MR dams produced more pups and heavier litters than HR dams. As with first litters, however, line by reproductive treatment interactions were not significant or important. Concurrent pregnancy and lactation (the HR treatment) had a similar dampening impact on the expected increase in litter size between first and second parity of both lines. Thus, lines divergently selected for toxicosis response did not differ significantly in the impact of increasing reproductive intensity on dam or pup growth, reproductive output through two parities or mature size. This conclusion should not be generalized. Selection responses in livestock should be monitored to ensure that improvement in one trait does not lead to deterioration in others.

Efficacy of intramammary infusion of ceftiofur hydrochloride at drying off for treatment and prevention of bovine mastitis during the nonlactating period

This study evaluated the efficacy of intramammary infusion of ceftiofur hydrochloride for the treatment of intramammary infections present at the last milking of lactation and for prevention of new intramammary infections during the nonlactating period. Cows were randomly assigned to five treatments (untreated negative control, 125, 250, and 500 mg of ceftiofur, and a positive control group receiving 300 mg cephapirin benzathine). A dose of 125 mg of ceftiofur per mammary quarter was effective for treatment of existing infections present at the time of milk cessation, but only the 500-mg dose of ceftiofur per mammary quarter was effective for both treatment of existing intramammary infections at the time of milk cessation and for prevention of new intramammary infections during the nonlactating period.

The risk of stillbirth in pregnancies before and after the onset of diabetes

AIMS

There is significant controversy as to whether or not stillbirth is increased in pregnancies prior to the onset of diabetes. An observed increase may be indicative of risks associated with untreated gestational diabetes. It is generally accepted that the risk of stillbirth in pregnancies that occur after the onset of diabetes has been diminished by modern obstetric care. However, the degree of residual risk is not well quantified. This study sought to examine the rates of stillbirth before and after the onset of diabetes compared with the general population.

METHODS

Retrospective cohort and nested case-control study. The study population was drawn from the UK-based General Practice Research Database, comprising some 300 practices, with data collection from the late 1980s until September 1999. From the base population, 913 diabetic women who had had a pregnancy were identified and 10,000 subjects without diabetes were randomly chosen as controls. Stillbirth was defined as death in utero after 20 weeks or with birth weight >500 g.

RESULTS

The stillbirth rates were higher in prediabetic pregnancies (19.7/1000), and in those occurring after the diagnosis of diabetes (33.7/1000), compared with the non-diabetic population (5.5/1000). Stillbirths were matched to four live births by maternal age and year of birth. Prediabetic pregnancy and pregnancy after the onset of diabetes were strongly associated with stillbirth: odds ratio (OR)=4.68 (1.67, 13.08) and OR=4.39 (2.22, 8.64), respectively.

CONCLUSIONS

The risk of stillbirth was increased in both prediabetic and post-diabetic pregnancy.

Medical management of missed abortion: a randomized clinical trial

OBJECTIVE

To estimate the efficacy of vaginal misoprostol for medical management of missed abortion.

METHODS

Fifty women with missed abortion were randomized to treatment with up to two 800 microg [DOSAGE ERROR CORRECTED] doses of misoprostol vaginally or a placebo. Participants were reviewed daily for 2 days, then again at 1 week. A blood sample for hemoglobin and serum beta-human chorionic gonadotropin (beta hCG) was obtained on day 1 and the hemoglobin level checked again on day 7. Complete abortion was defined as expulsion of the products of conception without dilation and curettage (D&C) and a negative follow-up urine beta hCG test after 4 weeks, or as no products of conception obtained at D&C in cases of suspected incomplete abortion.

RESULTS

The rate of complete abortion was 80% (20 of 25) in the misoprostol group and 16% (four of 25) in the placebo group, relative risk 0.20 (0.08, 0.50), P <.001. The rate of D&C was 28% (seven of 25) in the misoprostol group and 84% (21 of 25) in the placebo group, relative risk 0.33 (0.17, 0.64), P <.001. One participant in the misoprostol group had an emergency D&C for heavy bleeding. No participants required blood transfusion. The mean reduction in hemoglobin from day 1 to day 7 was 3.2 g/L in the misoprostol group versus 4.3 g/L in the placebo group, P = .72. Patient satisfaction with misoprostol treatment was high with 19 of 21 participants reporting they would try medical management again if they experienced another missed abortion.

CONCLUSION

Medical management of missed abortion is effective, reduces the need for D&C, and is associated with high levels of patient satisfaction.

Shetland Sheepdog leukodystrophy

Three litters of Shetland Sheepdog pups born to the same bitch and 2 different sires were studied because of uncontrollable seizures or progressive neurologic dysfunction. Four pups from the 1st litter, 1 from the 2nd litter, and 4 from the 3rd litter had severe diffuse spongy degeneration of the white matter of the brain and spinal cord. An inherited basis for this syndrome was suspected. The purpose of this study was to evaluate the pups with currently available screening tests for the metabolic, biochemical, infectious, and toxicologic causes of leukodystrophy seen in humans and animals. Computed tomography scans revealed diffuse hypomyelination in the affected pup. Complete postmortem examination, including histopathology and electron microscopy, delineated a leukodystrophy resembling human Canavan's disease, but amino acid and organic acid metabolism abnormalities were not detected. No etiology for Shetland Sheepdog leukodystrophy has been found, but this condition represents another familial disease in the purebred dog population.

Improved synchrony of estrus and ovulation with the addition of GnRH to a melengestrol acetate-prostaglandin F2alpha synchronization treatment in beef heifers

The objective of this experiment was to determine the effect of a GnRH injection within a melengestrol acetate (MGA)-PGF2alpha (PGF) estrus synchronization protocol on follicular dynamics and synchronization of estrus. Pubertal crossbred beef heifers (n = 34) were randomly assigned to one of two treatments. Both treatment groups were fed MGA (0.5 mg x hd(-1) x d(-1)) for 14 d and injected (i.m.) with PGF (25 mg of Lutalyse) 19 d after MGA withdrawal. Melengestrol acetate was delivered in a feed supplement of 1.8 kg x hd(-1) x d(-1). Seventeen heifers received an injection of GnRH (100 microg Cystorelin) 12 d after MGA withdrawal and 7 d before PGF. The control group (n = 17) received only MGA-PGF. Estrus was detected four times/d for 7 d beginning on the day PGF was injected. Transrectal ultrasonography was performed daily on eight heifers from each treatment to monitor ovarian activity and characterize changes in follicular dynamics after MGA withdrawal and until ovulation after PGF. Each of the GnRH-treated heifers either ovulated or had a luteinized dominant follicle following GnRH and subsequently initiated a new follicular wave (8/8, 100%). All GnRH-treated heifers (17/17, 100%) and 94% of controls (16/17) exhibited estrus after PGF. Estrus was exhibited over a 132-h period (12 to 144 h) for control heifers compared with 60 h (48 to 108 h) for GnRH-treated heifers. The peak synchronized period for both treatments was between 48 and 72 h after PGF, during which time 76% (13/17) of the GnRH-treated heifers exhibited estrus compared with 63% (10/16) for controls. Seventy-one percent (12/17) of the GnRH-treated heifers exhibited estrus from 48 to 60 h after PGF, compared with 38% (6/16) for controls (P < 0.05). In summary, injection of GnRH within a 14- to 19-d MGA-PGF protocol increased the synchrony of estrus during the synchronized period and concentrated the period of detected estrus. This protocol may offer potential for the fixed-time insemination of replacement beef heifers.

Interaction of endophyte-infected fescue and heat stress on ovarian function in the beef heifer

The objective of the experiment was to examine the interaction of endophyte-infected tall fescue and environmental temperature on follicular and luteal development and function in beef heifers. Heifers were fed endophyte-free or endophyte-infected tall fescue seed at thermoneutral or heat stress temperatures (n = 6/treatment) 4 wk before and 3 wk after synchronized ovulation. All heifers were subjected to thermoneutral conditions (19 degrees C, 50% relative humidity) from Days -7 to -2; temperature increased incrementally from Days -1 to 0 and cycled between 25 degrees C and 31 degrees C between Days 1 and 20 for heat-stressed heifers. Serum was collected and ovaries monitored every other day after induced luteolysis between Days 1 and 23 or until ovulation. Size and location of follicles >4 mm and corpora lutea were recorded. Serum concentrations of prolactin were reduced in heat-stressed heifers fed infected seed and both heat stress and infected seed decreased total cholesterol. Rectal temperature and respiration rate were greatest in heifers fed the infected seed when exposed to maximal temperatures. Heat stress led to reduced diameter of the corpus luteum and serum progesterone compared with thermoneutral conditions. Progesterone was reduced more so in heifers fed infected seed. The combination of infected seed and heat stress was associated with reduced diameter of the preovulatory dominant follicle, and consumption of infected seed led to fewer large follicles during the estrous cycle. Both stressors led to reduced serum estradiol. Impaired follicle function may explain reduced pregnancy rates commonly observed in heifers grazing infected tall fescue pasture.

Prediabetes and perinatal mortality

OBJECTIVE

The association between gestational diabetes mellitus (GDM) and perinatal outcome is largely based on case series and retrospective studies that found an increased risk of perinatal mortality and stillbirth as the onset of diabetes approached. Our objective was to assess the relationship between latency to diabetes and perinatal outcome of prediabetic pregnancies in a contemporary population of women with adult-onset diabetes.

RESEARCH DESIGN AND METHODS

A population of 403 diabetic women from two recruitment sites completed a pretested questionnaire.

RESULTS

Details of 1,181 pregnancy outcomes were obtained. This comprised 1,024 live births, 22 stillbirths, and 8 early neonatal deaths. Crude analysis suggested a relationship between time to diabetes (latency) < or =20 years and both perinatal death and stillbirth: odds ratio (95% CI), 2.41 (1.17-4.95) and 2.15 (0.93-4.98). Generalized additive modeling revealed a nonlinear relationship between the variables time to diabetes, and maternal age and perinatal outcome. Final logistic regression analysis was then performed for the outcomes perinatal death and stillbirth, with maternal age as a second-degree polynomial, year of birth as a continuous variable, and time to diabetes dichotomized < or =20 years to diagnosis and >20 years. This final analysis documented a significant association between time to diabetes < or =20 years and both perinatal death (4.06 [1.79-9.36]) and stillbirth (3.35 [1.25-9.05]).

CONCLUSIONS

There appeared to be an increased risk of perinatal death and stillbirth in pregnancies occurring in the last 20 years before the diagnosis of diabetes.

Uterine rupture during induced trial of labor among women with previous cesarean delivery

OBJECTIVE

This study was undertaken to compare the rates of uterine rupture during induced trials of labor after previous cesarean delivery with the rates during a spontaneous trial of labor.

STUDY DESIGN

All deliveries between 1992 and 1998 among women with previous cesarean delivery were evaluated. Rates of uterine rupture were determined for spontaneous labor and different methods of induction.

RESULTS

Of 2119 trials of labor, 575 (27%) were induced. The overall rate of uterine rupture was 0.71% (15/2119). The uterine rupture rate with induced trial of labor (8/575; 1.4%) was significantly higher than with a spontaneous trial of labor (7/1544; 0.45%; P =.0004). Uterine rupture rates associated with different methods of induction were compared with the rate seen with spontaneous labor and were as follows: prostaglandin E(2) gel, 2.9% (5/172; P =.004); intracervical Foley catheter, 0.76% (1/129; P =.47); and labor induction not requiring cervical ripening, 0.74% (2/274; P =.63). The uterine rupture rate associated with inductions other than with prostaglandin E(2) was 0.74% (3/474; P =.38). The relative risk of uterine rupture with prostaglandin E(2) use versus spontaneous trial of labor was 6.41 (95% confidence interval, 2. 06-19.98).

CONCLUSION

Induction of labor was associated with an increased risk of uterine rupture among women with a previous cesarean delivery, and this association was highest when prostaglandin E(2) gel was used.

Effects of anesthesia, surgery, and intravenous administration of fluids on plasma antidiuretic hormone concentrations in healthy dogs

OBJECTIVE

To evaluate effects of anesthesia, surgery, and intravenous administration of fluids on plasma concentrations of antidiuretic hormone (ADH), concentration of total solids (TS), PCV, arterial blood pressure (BP), plasma osmolality, and urine output in healthy dogs.

ANIMALS

22 healthy Beagles.

PROCEDURE

11 dogs did not receive fluids, and 11 received 20 ml of lactated Ringer's solution/kg of body weight/h. Plasma ADH adn TS concentrations, PCV, osmolality, and arterial BP were measured before anesthesia (T0) and after administration of preanesthetic agents (T1), induction of anesthesia (T2), and 1 and 2 hours of surgery (T3 and T4, respectively). Urine output was measured at T3 and T4.

RESULTS

ADH concentrations increased at T1, T3, and T4, compared with concentrations at T0. Concentration of TS and PCV decreased at all times after administration of preanesthetic drugs. Plasma ADH concentration was less at T3 in dogs that received fluids, compared with those that did not. Blood pressure did not differ between groups, and osmolality did not increase > 1% from To value at any time. At T4, rate of urine production was less in dogs that did not receive fluids, compared with those that did.

CONCLUSIONS AND CLINICAL RELEVANCE

Plasma ADH concentration increased and PCV and TS concentration decreased in response to anesthesia and surgery. Intravenous administration of fluids resulted in increased urine output but had no effect on ADH concentration or arterial BP. The causes and effects of increased plasma ADH concentrations may affect efficacious administration of fluids during the perioperative period in dogs.

S49 cells endogenously express subtype 2 somatostatin receptors which couple to increase protein tyrosine phosphatase activity in membranes and down-regulate Raf-1 activity in situ

S49 cells expressed type 2 somatostatin receptors (sstr2) by immunoblotting. Analysis by reverse transcription and polymerase chain reaction (RT-PCR) methodologies showed that S49 cells express predominantly sstr2A and sstr2B mRNAs; other subtypes were either not detected, in the case of sstr1, sstr3, sstr4, or variably detected, in the case of sstr5. No mutations were present in S49 cells at codon 12, 13, or 61 of the N-, K-, or H-ras genes. Nevertheless, randomly growing S49 cells contained Raf-1 activity by specific immune complex kinase assays. Treatment of S49 cells with somatostatin transiently inactivated the basal activity of Raf-1, but not that of B-Raf. Addition of somatostatin plus guanyl-5'-yl imidodiphosphate (GMPPNP) to S49 membranes stimulated PTPase activity. The concentration dependence for stimulation of PTPase activity correlated with high affinity binding of [125I-Tyr11]somatostatin-14. Both the effect of somatostatin to stimulate PTPase activity and to inactivate Raf-1 were abrogated by PTx. PTPase activity stimulated by somatostatin plus GMPPNP was recovered in a peak of high apparent M(r) (670,000) after solubilisation with Triton X-100 and Superose 6 chromatography. Furthermore, addition of activated, brain G alpha i/o subunits to fractions from control membranes stimulated PTPase activity in the high M(r) peak. Thus, S49 membranes contain a G-protein regulated PTPase (PTPase-G), and PTPase-G in these cells may reside in a high molecular weight complex.

Activation in vitro of somatostatin receptor subtypes 2, 3, or 4 stimulates protein tyrosine phosphatase activity in membranes from transfected Ras-transformed NIH 3T3 cells: coexpression with catalytically inactive SHP-2 blocks responsiveness

Somatostatin receptors (sstr) subtypes 1-5 were transiently expressed in NIH 3T3 cells stably transformed with Ha-Ras(G12V) to assess the ability of each receptor to stimulate protein tyrosine phosphatase (PTPase) activity in vitro. Treatment of membranes from sstr2-, sstr3-, or sstr4-expressing cells with somatostatin-14 plus guanyl-5'-yl imidodiphosphate (GMPPNP) increased PTPase activity, and this stimulation was pertussis toxin-sensitive. Somatostatin alone, GMPPNP alone, or somatostatin plus GDP were ineffective under these conditions. sstr1 and sstr5 failed to increase PTPase activity although both receptors were expressed, as assessed by appearance of high-affinity binding sites for [125I-Tyr11]somatostatin-14. Somatostatin plus GMPPNP stimulated PTPase activity in vitro when sstr2 was coexpressed with wild type PTP1B or a Cys to Ser (C/S), catalytically inactive PTP1B or with wild type SH2-domain containing PTPase SHP-2. However, coexpression with catalytically inactive C/S SHP-2 abrogated this response. Thus, three of the five cloned sstr's can couple to activate PTPase in this cellular background. Abrogation of the response by C/S SHP-2 strongly suggests, but does not prove, a role for SHP-2 in the mechanism.

Evaluation of the twin peak or lambda sign in determining chorionicity in multiple pregnancy

OBJECTIVE

To assess prospectively the diagnostic capabilities of ultrasound assessment, using the twin peak or lambda sign, in determining chorionicity in multiple pregnancy.

METHODS

Fifty-five cases of multiple pregnancy were assessed. Real-time ultrasound scans of the origin of the inter-twin membrane for the presence or absence of the twin peak/lambda sign were performed and permanent images recorded. Chorionicity was determined by placental pathologic analysis.

RESULTS

Presence or absence of the twin peak/lambda sign as determined by real-time ultrasound correctly predicted chorionicity in 34 of 36 dichorionic and seven of eight monochorionic twin pregnancies: sensitivity for dichorionicity 94%, specificity 88%, positive predictive value 97%, and negative predictive value 78%. Real-time assessment was superior to analysis of permanent films.

CONCLUSION

Ultrasound assessment of chorionicity using the twin peak/lambda sign has high sensitivity and specificity, but accuracy may not be sufficient to guide clinical management in all cases.

Immunohistochemical identification of B and T lymphocytes in formalin-fixed, paraffin-embedded feline lymphosarcomas: relation to feline leukemia virus status, tumor site, and patient age

The lymphocyte phenotype of 70 formalin-fixed, paraffin-embedded feline lymphosarcomas (LSAs) was determined immunohistochemically using a T cell polyclonal antibody, and a B cell monoclonal antibody. Forty-seven of 70 (67%) tumors were T cell, 19/70 (27%) were B cell, and 4/70 (6%) did not stain with either marker. Thirty-eight of 70 (54%) tumors were positive for feline leukemia virus (FeLV) antigen by immunohistochemistry (IHC), and 52/70 (74%) tumors were positive for FeLV DNA using the polymerase chain reaction (PCR). B cell tumors were as frequently FeLV-positive as T cell tumors using either IHC or PCR. Intestinal tumors were more likely to be B cell than T. The incidence of B and T cell tumors was not different among young (< or = 3 y), middle-aged (> 3 y to < or = 8 y), and old (> 8 y) cats. Both B and T cell tumors from old cats were FeLV-positive more often by PCR than by IHC. Feline leukemia virus DNA but not antigen, was detected in B cell tumors and intestinal tumors from cats > 8 y as often as it was detected in B cell tumors and intestinal tumors from cats < or = 8 y. Previously, most B cell and intestinal tumors from old cats were considered to be negative for FeLV. Here, the results suggest involvement of latent or replication-defective forms of the virus in such tumors from old cats. This study supports a role for FeLV in feline B cell as well as T cell tumorigenesis.

Activation of a protein tyrosine phosphatase and inactivation of Raf-1 by somatostatin

Human somatostatin receptor 3 ('hsstr3') was transiently expressed in NIH 3T3 cells stably transformed with Ha-Ras (G12V). Somatostatin activated a protein tyrosine phosphatase and inactivated the constitutively active, membrane-associated form of the Raf-1 serine kinase present in these cells in vivo and in vitro.

Inactivation of raf-1 by a protein-tyrosine phosphatase stimulated by GTP and reconstituted by Galphai/o subunits

A membrane-associated form of Raf-1 in v-Ras transformed NIH 3T3 cells can be inactivated by protein phosphatases regulated by GTP. Herein, a distinct protein-tyrosine phosphatase (PTPase) in membrane preparations from v-Ras transformed NIH 3T3 cells was found to be activated by guanyl-5'-yl imidodiphosphate (GMPPNP) and was identified as an effector for pertussis toxin (PTx)-sensitive G-protein alpha subunits. PTPase activation was blocked by prior treatment of cells with PTx. PTPase activation by GTP, but not GMPPNP, was transient. A GMPPNP-stimulated PTPase (PTPase-G) co-purified with Galphai/o subunits during Superose 6 and Mono Q chromatography. PTPase-G activity in Superose 6 fractions from GDP-treated membranes was reconstituted by activated Galphai/o, but not G beta gamma, subunits. PTPase-G may contribute to GMPPNP-stimulated inactivation of Raf-1 in v-Ras cell membranes because Raf-1 inactivation was PTx-sensitive and PTPase-G inactivated exogenous Raf-1.

Canine distemper virus-like infection in a captive African lioness

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Specificity and localization of lipolytic activity in adult Drosophila melanogaster

The triacylglycerol lipases present in adult Drosophila melanogaster have been investigated. Different lipase activities are present in various tissues in the fly. In particular, an abundant lipase activity is present in the male accessory gland. An esterase null mutant was used to confirm that the enzyme activity was due to a distinct lipase and not non-specific activity from esterase 6 which is also abundant in accessory glands. The properties of the accessory-gland lipase were investigated, and pH optima and substrate utilization suggest that it has some similarities to vertebrate bile-salt-stimulated lipase. Lipase activity is significantly reduced in males and increased in females shortly after mating. This finding suggests that lipase activity is transferred to the female and may be important in mating and reproduction in Drosophila.

The multifunctional role of hormone-sensitive lipase in lipid metabolism

Hormone sensitive lipase (HSL) is an enzyme of relatively broad specificity, having the ability to hydrolyze tri-, di- and mono-acylglycerols as well as cholesterol esters and small water-soluble substrates. This broad specificity allows HSL to perform a variety of functions in several tissues. A key feature of HSL is its ability to be activated via phosphorylation by cyclic AMP-dependent protein kinase. In addition it is phosphorylated at a second site by several kinases, notably AMP-activated protein kinase. Phosphorylation of this site apparently plays a role in rendering the enzyme hormone-insensitive, in that prior phosphorylation at site 2 prevents phosphorylation and activation at site 1 by cyclic AMP-dependent protein kinase. Investigation of the protein phosphatases responsible for dephosphorylation of these sites has indicated that phosphatase 2A plays a predominant role but also that protein phosphatase 2C is a significant phosphatase targeted against both phosphorylation sites. Evidence indicates that HSL has at least three functional domains which contain (a) the phosphorylation sites which control activity, (b) the active site responsible for the catalytic activity and (c) a lipid binding site responsible for anchoring the lipase at the water-lipid interface. Using limited proteolytic studies we have found that it is possible to cleave HSL into several fragments including a stable domain of M(r) approximately 17.6 kDa which contains the active site serine residue. Digestion under similar conditions also generates a stable domain of M(r) approximately 11.5 kDa containing both phosphorylation sites. Furthermore, under appropriate conditions it is possible to digest HSL and retain activity against water-soluble substrates but with the concomitant loss of activity against triacylglycerol, implying that a lipid binding domain is lost during this procedure. HSL is responsible for the neutral cholesterol esterase activity in macrophages and it may play a role in the accumulation of cholesterol esters which occur during the development of foam cells. HSL activity is reduced in macrophage foam cells, at least partly due to increased activity of a cytosolic HSL inhibitor protein. A finding unexplained for many years has been that, although lipolysis can be stimulated 50-100-fold in adipocytes by lipolytic hormones, HSL can apparently only be activated 2-3-fold via phosphorylation in vitro by cyclic AMP-dependent protein kinase. One possibility to explain this discrepancy is that an additional anchoring protein is missing from the in vitro system and indirect evidence is now accumulating for such a protein.

The protein phosphatases responsible for dephosphorylation of hormone-sensitive lipase in isolated rat adipocytes

The levels of the cytosolic serine/threonine protein phosphatases (PP) in rat adipocyte extracts have been determined, by using both reference substrates and hormone-sensitive lipase (HSL) as substrates. Adipocytes contain significant levels of both PP1 and 2A (1.6 and 2.0 m-units/ml of packed cells respectively), with lower levels of PP2C and virtually no PP2B activity. PP2A and 2C exhibit similar degrees of activity against HSL phosphorylated at site 1, together accounting for 92% of the total. In contrast, site 2 is dephosphorylated predominantly by PP2A (over 50% of total activity), whereas PP1 and PP2C contribute approx. 20% and 30% respectively to the total phosphatase activity against that site. Total phosphatase activity in the adipocyte extracts was 2-3-fold higher against site 2 than against site 1. The possible significance of these findings to the regulation of HSL activity in adipose tissue in vivo is discussed.

Reverse chromosome painting: a method for the rapid analysis of aberrant chromosomes in clinical cytogenetics

We describe a method, termed reverse chromosome painting, which allows the rapid analysis of the content and breakpoints of aberrant chromosomes. The method involves the sorting of small numbers of the aberrant chromosome from short term blood culture preparations or cell lines by using bivariate flow karyotype analysis. The sorted chromosomes are amplified and biotin labelled enzymatically using a degenerate oligonucleotide-primed polymerase chain reaction (DOP-PCR), the product annealed to metaphase spreads from normal subjects, and hybridisation detected using fluorescence in situ hybridisation (FISH). We show the usefulness of this method for routine clinical cytogenetics by the analysis of cases involving an insertion, a deletion, a translocation, and two cases of a chromosome with additional material of unknown origin. The method has particular application for the rapid resolution of the origin of de novo unbalanced chromosome duplications.

Do you want an articulation plan? This is how the Colorado Model was developed

Directors and faculty members of all the Colorado LPN, ADN, and BSN programs have joined together to formulate a model for statewide nursing program articulation. All schools will activate the model by January, 1992. The process by which this was accomplished is discussed in this article.

Hemogram changes in lactating dairy cows given human recombinant granulocyte colony stimulating factor (r-MethuG-CSF)

As a prelude to mammary gland challenge experiments, this investigation was implemented to assess the hematologic changes in lactating dairy cattle induced by two dosage regimes of human recombinant colony stimulating factor (Hr-GCSF). This study documents the capability of the human recombinant colony stimulating factor to produce hematologic changes in both a time and dose dependent manner when administered to the adult lactating bovine. A screening dose of 1 microgram/kg of Hr-GCSF administered to three study subjects produced a three- to four-fold increase in peripheral blood mature neutrophil counts (P less than 0.043) by day 12 of the trial. The priming dose treatment group of four lactating cows (3 micrograms/kg of Hr-GCSF) exhibited a three- to five-fold increase in peripheral blood mature neutrophil counts (P less than 0.05) and two- to three-fold increases in white blood cell counts by day 5 of the trial. Hematologic examinations of the control group (n = 4; no Hr-GCSF administration) did not detect significant changes in their neutrophil counts over baseline values. The milk somatic cell counts did not statistically shift over baseline values in any of the control or Hr-GCSF treatment groups. When attempting to alter the course of infectious disease processes, potential applications of colony stimulating factors provide interesting speculations about new therapeutic modalities.

Intrapartum asphyxia in the preterm fetus less than 2000 gm

The incidence of intrapartum asphyxia in the preterm fetus less than 2000 gm (6%) is greater than that in the mature fetus (2%). Severe antepartum hemorrhage is the only clinical marker predictive of asphyxia in the preterm fetus. Marked deceleration patterns and particularly late decelerations may be of predictive value for asphyxia. However, many intrapartum asphyxial episodes are not identified on the basis of clinical observations. Consistent diagnosis of intrapartum asphyxia in the preterm fetus requires routine umbilical cord blood gas and acid-base assessment at delivery.

Primary congenital glaucoma

Primary congenital glaucoma is a rare but potentially devastating disorder that family physicians must recognize as early as possible in infants and young children. Symptoms, which may not be present at birth, classically include photophobia, excessive tearing and blepharospasm. The cornea may be enlarged and hazy. Increased intraocular pressure rapidly damages the optic nerve in infants. Treatment includes surgery with regular follow-up evaluation.

A unique postmarket outpatient surveillance program of cimetidine: report on phase II and final summary

A unique outpatient surveillance program consisting of an initial phase (phase I) and a follow-up phase (phase II) was initiated 7 months after FDA approval of cimetidine. The methodology used in this extensive postmarket surveillance program provided information on adverse effects in a large number of patients both on an acute and chronic (up to 12 months) basis. Phase I gathered data on 9907 patients from 1049 physicians over a 3-month period. The overall incidence of adverse effects in this phase was 4.4%, and they did not differ in type from those of premarketing controlled studies. Six months after termination of phase I, phase II was initiated, and follow-up data were requested on the same group of patients from the same 1049 physicians. Case report forms were received from 905 physicians on 7248 patients representing 9763 courses of cimetidine therapy. A total of 162 adverse effects were reported by 138 patients for an incidence of 1.8%. As in postmarket surveillance I, the adverse effects reported in postmarket surveillance II were not different from those previously reported in clinical studies, published reports, or via the spontaneous reporting system. This postmarket surveillance program designed and successfully tested methodology useful for future surveillance studies, and confirmed the safety of cimetidine in a large cohort of patients which remains a valuable source for future data accumulation.

Impulse conduction in inhomogeneous axons: effects of variation in voltage-sensitive ionic conductances on invasion of demyelinated axon segments and preterminal fibers

Conduction in inhomogeneous axons may be blocked by several mechanisms. Conduction in demyelinated axons may fail since normal internodal membrane is inexcitable, because values of sodium conductance are too low to support impulse conduction. In addition, focal loss of myelin causes increased current leakage which slows or blocks invasion of impulses into the demyelinated zone due to inadequate current density. Similar considerations apply to the invasion of non-myelinated preterminal axons from myelinated parent fibers, where conduction can be blocked as a result of inadequate current density. A cable model of an axon is presented which allows myelinated regions, regions without myelin, and variable length transition zones of redistributed channel densities, to be studied. Action potentials and membrane currents were studied. Computer simulations using this model show that the safety factor for invasion is dependent on temperature. These studies also show that small changes in axon membrane properties, at the transition region between the myelinated zone and the region without myelin, may promote invasion of the region without myelin. In particular, increasing sodium conductance (gNa) or decreasing potassium conductance (gK) promotes invasion. Because of the non-linear behavior of excitable membranes the spatial distribution of channels is shown also to have significant effects on invasion. Thus, relatively small degrees of membrane reorganization may lead to functional changes with respect to the invasion of demyelinated axon regions. Similarly, the properties of the heminode at the distal part of the parent myelinated fiber may determine the invasion characteristics of non-myelinated terminal axons.

Conduction of trans of impulses in uniform myelinated fibers: computed dependence on stimulus frequency

The conduction of trains of action potentials in myelinated fibers was studied using computer simulations based on a modification of the Hodgkin-Huxley equations. Stimulation at short but regular interstimulus intervals caused some stimuli to fail to elicit propagated action potentials. Propagated impulse trains observed close to the stimulation site, elicited by high frequency stimulus trains, took the form of "clusters" of impulses, e.g. doublets or triplets. When these impulse trains were observed at distances farther from the stimulation site, interspike intervals were more uniform. For interstimulus intervals of less than 10 ms, distant intervals between impulses were relatively insensitive to the temporal patterning of impulses at the initiation zone and tended toward regular intervals corresponding to the average interstimulus intervals for propagated stimuli. This tendency toward uniform intervals between impulses was also observed for lower average frequency stimulus trains with irregular interstimulus intervals. Moreover, for the first two stimuli in a train, there was a very tendency toward impulse entrainment. These results indicate that intervals between impulses along unbranched myelinated axons are not fixed, but vary according to the site along the conduction pathway where they are observed. The tendency toward entrainment, and regularization of intervals, may represent a factor limiting the frequency with which interval-coded impulses are initiated.

A real-time on-line digital computer method for monitoring myocardial supply: demand ratio

The Myocardial Supply: Demand Ratio reflects the ratio of subendocardial perfusion to subendocardial oxygen demands. A method is described for calculating and continuously monitoring the Myocardial Supply: Demand Ratio using digital computer in real-time.