Breasi-CRISPR: an efficient genome-editing method to interrogate protein localization and protein-protein interactions in the embryonic mouse cortex

In developing tissues, knowing the localization and interactors of proteins of interest is key to understanding their function. Here, we describe the Breasi-CRISPR approach (Brain Easi-CRISPR), combining Easi-CRISPR with in utero electroporation to tag endogenous proteins within embryonic mouse brains. Breasi-CRISPR enables knock-in of both short and long epitope tag sequences with high efficiency. We visualized epitope-tagged proteins with varied expression levels, such as ACTB, LMNB1, EMD, FMRP, NOTCH1 and RPL22. Detection was possible by immunohistochemistry as soon as 1 day after electroporation and we observed efficient gene editing in up to 50% of electroporated cells. Moreover, tagged proteins could be detected by immunoblotting in lysates from individual cortices. Next, we demonstrated that Breasi-CRISPR enables the tagging of proteins with fluorophores, allowing visualization of endogenous proteins by live imaging in organotypic brain slices. Finally, we used Breasi-CRISPR to perform co-immunoprecipitation mass-spectrometry analyses of the autism-related protein FMRP to discover its interactome in the embryonic cortex. Together, these data demonstrate that Breasi-CRISPR is a powerful tool with diverse applications that will propel the understanding of protein function in neurodevelopment.

Universal use of surgical masks is tolerated and prevents respiratory viral infection in stem cell transplant recipients

Prevention of respiratory viral infection in stem cell transplant patients is important due to its high risk of adverse outcome. This single-centre, mixed methods study, conducted before the severe acute respiratory syndrome coronavirus-2 pandemic, explored the barriers and facilitators to a policy of universal mask use by visitors and healthcare workers, and examined the impact of the first year of introduction of the policy on respiratory viral infection rates compared with preceding years, adjusted for overall incidence. Education around universal mask use was highlighted as being particularly important in policy implementation. A significant decrease in respiratory viral infection was observed following introduction.

Conditional Myh9 and Myh10 inactivation in adult mouse renal epithelium results in progressive kidney disease

Actin-associated nonmuscle myosin II (NM2) motor proteins play critical roles in a myriad of cellular functions, including endocytosis and organelle transport pathways. Cell type–specific expression and unique subcellular localization of the NM2 proteins, encoded by the Myh9 and Myh10 genes, in the mouse kidney tubules led us to hypothesize that these proteins have specialized functional roles within the renal epithelium. Inducible conditional knockout (cKO) of Myh9 and Myh10 in the renal tubules of adult mice resulted in progressive kidney disease. Prior to overt renal tubular injury, we observed intracellular accumulation of the glycosylphosphatidylinositol-anchored protein uromodulin (UMOD) and gradual loss of Na⁺ K⁺ 2Cl^– cotransporter from the apical membrane of the thick ascending limb epithelia. The UMOD accumulation coincided with expansion of endoplasmic reticulum (ER) tubules and activation of ER stress and unfolded protein response pathways in Myh9&10-cKO kidneys. We conclude that NM2 proteins are required for localization and transport of UMOD and loss of function results in accumulation of UMOD and ER stress–mediated progressive renal tubulointerstitial disease. These observations establish cell type–specific role(s) for NM2 proteins in regulation of specialized renal epithelial transport pathways and reveal the possibility that human kidney disease associated with MYH9 mutations could be of renal epithelial origin.

Adult mouse renal epithelium specific knockout of Myh9 and Myh10 genes result in kidney disease.

Energy of the quasi-free electron in H2, D2, and O2: Probing intermolecular potentials within the local Wigner-Seitz model

We present for the first time the quasi-free electron energy V0(ρ) for H2, D2, and O2 from gas to liquid densities, on noncritical isotherms and on a near critical isotherm in each fluid. These data illustrate the ability of field enhanced photoemission (FEP) to determine V0(ρ) accurately in strongly absorbing fluids (e.g., O2) and fluids with extremely low critical temperatures (e.g., H2 and D2). We also show that the isotropic local Wigner-Seitz model for V0(ρ)--when coupled with thermodynamic data for the fluid--can yield optimized parameters for intermolecular potentials, as well as zero kinetic energy electron scattering lengths.

Epithelial-specific A2B adenosine receptor signaling protects the colonic epithelial barrier during acute colitis

Central to inflammatory bowel disease (IBD) pathogenesis is loss of mucosal barrier function. Emerging evidence implicates extracellular adenosine signaling in attenuating mucosal inflammation. We hypothesized that adenosine-mediated protection from intestinal barrier dysfunction involves tissue-specific signaling through the A2B adenosine receptor (Adora2b) at the intestinal mucosal surface. To address this hypothesis, we combined pharmacologic studies and studies in mice with global or tissue-specific deletion of the Adora2b receptor. Adora2b(-/-) mice experienced a significantly heightened severity of colitis, associated with a more acute onset of disease and loss of intestinal epithelial barrier function. Comparison of mice with Adora2b deletion on vascular endothelial cells (Adora2b(fl/fl)VeCadCre(+)) or intestinal epithelia (Adora2b(fl/fl)VillinCre(+)) revealed a selective role for epithelial Adora2b signaling in attenuating colonic inflammation. In vitro studies with Adora2b knockdown in intestinal epithelial cultures or pharmacologic studies highlighted Adora2b-driven phosphorylation of vasodilator-stimulated phosphoprotein (VASP) as a specific barrier repair response. Similarly, in vivo studies in genetic mouse models or treatment studies with an Adora2b agonist (BAY 60-6583) recapitulate these findings. Taken together, our results suggest that intestinal epithelial Adora2b signaling provides protection during intestinal inflammation via enhancing mucosal barrier responses.

A stochastic mathematical model of the within-herd transmission dynamics of Porcine Reproductive and Respiratory Syndrome Virus (PRRSV): fade-out and persistence

A stochastic, mathematical model of a farrow-finish pig herd was developed and used to investigate the within-herd transmission dynamics of PRRSV, and to examine patterns of on-farm persistence and fade-out. The model was structured to represent the management of a typical European pig herd. Three parameters determining the natural history of infection were derived from the literature. Transmission parameters were chosen using PRRSV antibody data from a cross-sectional study of 103 pig herds (Evans et al., 2008). The seroprevalence by age was generated from the model at 21-day intervals and was compared to the cross-sectional field data using log-likelihood, accounting for the accuracy of the ELISA test used. The model was run for various isolation practices of purchased gilts, contact structure, herd size and the frequency of re-introduction of infectious gilts. The time-dependent log-likelihood patterns varied between herds in a similar way to patterns observed from serological values from the 103 farms. Essentially they indicated two patterns of seroprevalence: herds in which PRRSV was stably persistent, and herds in which PRRSV was unstable, either recently introduced or recently faded-out. With a herd size of 327 sows with identical management, fade-out of virus occurred within 4 weeks in 21.9% of simulations. Without isolation of gilts from sows, fade-out within 250 days decreased from 81.6% to 14.3% and for herd sizes of 75, 150, 300 and 600, the probability of persistence of virus for >1200 days was 4%, 13.4%, 20.4% and 18.2%, respectively. Introduction of virus at a rate of approximately 0.37 times per year resulted in virus persisting for >1200 days in 32.4% of simulations, compared with 17.6% for no re-introduction. Fade-out of virus was most likely to occur within breeding females before virus reached young stock. Persistence was more likely once PRRSV was present in piglets which in turn infected rearing-pigs. The probability of persistence was higher with increased herd size, increased contact between different age groups and increased re-introduction of infectious gilts. The ability of the model to capture the variability in cross-sectional, age-related serological patterns suggests that the processes of re-introduction, persistence and fade-out of PRRSV play critical roles in PRRSV epidemiology. The potential importance to pig production and transmission of virus between herds is discussed.

Energy of the Quasi-Free Electron in Supercritical Krypton near the Critical Point

Field ionization measurements of high-n CH(3)I and C(2)H(5)I Rydberg states doped into krypton are presented as a function of krypton number density along the critical isotherm. These data exhibit a decrease in the krypton-induced shift of the dopant ionization energy near the critical point. This change in shift is modeled to within +/-0.2% of experiment using a theory that accounts for the polarization of krypton by the dopant ion, the polarization of krypton by the quasi-free electron that arises from field ionization of the dopant, and the zero point kinetic energy of the free electron. The overall decrease in the shift of the dopant ionization energy near the critical point of krypton, which is a factor of 2 larger than that observed in argon, is dominated by the increase in the zero point kinetic energy of the quasi-free electron.

Evaluation of extracorporeal shock wave therapy in Peyronie's disease

OBJECTIVES

To evaluate the results of extracorporeal shock wave therapy (ESWT) in patients with Peyronie's disease.

METHODS

This study included 42 patients (mean age 55.4 years, range 32 to 72, SD 9.92) with Peyronie's disease. The mean duration of disease was 16.5 months (range 3 to 60, SD 13.31). Before treatment, the degree of angulation was assessed artificially by injection of 10 to 20 microg alprostadil, and Polaroid photographs were taken. Patients were also questioned about pain on erection, whether sexual intercourse was possible, and the quality of erections. All were initially treated with three sessions of ESWT (3000 shock waves). After three sessions, patients who believed that improvement had resulted or who wanted to undergo additional treatment went on to have further sessions. The mean duration of follow-up was 5.9 months (range 2 to 18, SD 4.4), after which the results were analyzed.

RESULTS

Those who believed that improvement in angulation had resulted were asked to provide Polaroid photographs to assess the improvement objectively. Six (14%) said that they had excellent results, 21 (50%) had significant improvement, 7 (17%) had slight improvement, and 8 (19%) had no change. Of the 25 who had pain on erection before treatment, 21 (84%) reported complete or near complete relief after treatment. Five patients said that the quality of the erections had improved after treatment. Eight patients complained of mild and one of severe pain during or immediately after treatment; 2 of these 9 patients had both pain and bruising.

CONCLUSIONS

The initial results with ESWT are promising, with minimal complications. The long-term results need to be evaluated.

Effects of dexamethasone on antigen-induced airway eosinophilia and M(2) receptor dysfunction

In antigen-challenged guinea pigs, airway hyperreactivity is due to recruitment of eosinophils to the airway nerves and dysfunction of M(2) muscarinic receptors. M(2) receptor dysfunction is caused by eosinophil major basic protein, which is an allosteric antagonist at the receptor. Because glucocorticoids inhibit airway hyperreactivity in humans and in animal models of asthma, we tested whether dexamethasone treatment (6 microg. kg(-)(1). d(-)(1) for 3 d, intraperitoneal) before antigen challenge prevents M(2) receptor dysfunction and airway hyperreactivity. Guinea pigs were sensitized to ovalbumin via intraperitoneal injections, and were challenged with ovalbumin via inhalation. Twenty-four hours later, hyperreactivity and M(2) receptor function were tested. Antigen-challenged animals were hyperreactive to vagal stimulation, and demonstrated loss of M(2) receptor function. Dexamethasone pretreatment prevented hyperreactivity and M(2) receptor dysfunction in antigen-challenged guinea pigs. Antigen challenge resulted in recruitment of eosinophils to the airways and to the airway nerves. Dexamethasone prevented recruitment of eosinophils to the airway nerves but did not affect total eosinophil influx into the airways. These results demonstrate that dexamethasone prevents antigen-induced hyperreactivity by protecting neuronal M(2) muscarinic receptors from antagonism by eosinophil major basic protein, and this protective mechanism appears to be by specifically inhibiting eosinophil recruitment to the airway nerves.

Pre-reactive complexes in mixtures of water vapour with halogens: characterisation of H2O...ClF and H2O...F2 by a combination of rotational spectroscopy and ab initio calculations

Complexes H2O...ClF and H2O...F2 were detected by means of their ground-state rotational spectra in mixtures of water vapour with chlorine monofluoride and difluorine, respectively. A fast-mixing nozzle was used in conjunction with a pulsed-jet, Fourier-transform microwave spectrometer to preclude the vigorous chemical reaction that these dihalogen species undergo with water. The ground-state spectra of seven isotopomers (H2 16O...35ClF, H2 16O...ClF, H2 18O...35ClF, D2 16O... 35ClF, D2 16O...37ClF, HDO...35ClF and HDO...37ClF) of the ClF complex and five isotopomers (H2O...F2, H2 18O...F2, D2O...F2, D2 18O...Fi and HDO...F2) of the F2 complex were analysed to yield rotational constants, quartic centrifugal distortion constants and nuclear hyperfine coupling constants. These spectroscopic constants were interpreted with the aid of simple models of the complexes to give effective geometries and intermolecular stretching force constants. Isotopic substitution showed that in each complex the H2O molecule acts as the electron donor and either CIF or F2 acts as the electron acceptor, with nuclei in the order H2O...ClF or H2O...F2. For H2O...ClF, the angle phi between the bisector of the HOH angle and the O...Cl internuclear line has the value 58.9(16)degrees, while the distance r(O...Cl)= 2.6081(23) A. The corresponding quantities for H2O...F2 are phi = 48.5(21)degrees and r(O...Fi) = 2.7480(27) A, where Fi indicates the inner F atom. The potential energy V(phi) as a function of the angle phi was obtained from ab initio calculations at the aug-cc-pVDZ/MP2 level of theory for each complex by carrying out geometry optimisations at fixed values of phi in the range +/-80degrees. The global minimum corresponded to a complex of Cs symmetry with a pyramidal configuration at O in each. The function V(phi) was of the double-minimum type in each case with equilibrium values phie = +/-55.8degrees and +/-40.5degrees for H2O...ClF and H2O...F2, respectively. The barrier at the planar C2v conformation was V0= 174cm(-1) for H2O...ClF and 7cm(-1) for H2O...F2. For the latter complex, the zero-point energy level lies above the top of the barrier.

Substance P-induced airway hyperreactivity is mediated by neuronal M(2) receptor dysfunction

Neuronal muscarinic (M(2)) receptors inhibit release of acetylcholine from the vagus nerves. Hyperreactivity in antigen-challenged guinea pigs is due to blockade of these M(2) autoreceptors by eosinophil major basic protein (MBP) increasing the release of acetylcholine. In vivo, substance P-induced hyperactivity is vagally mediated. Because substance P induces eosinophil degranulation, we tested whether substance P-induced hyperreactivity is mediated by release of MBP and neuronal M(2) receptor dysfunction. Pathogen-free guinea pigs were anesthetized and ventilated. Thirty minutes after intravenous administration of [Sar(9),Met(O(2))(11)]- substance P, guinea pigs were hyperreactive to vagal stimulation and M(2) receptors were dysfunctional. The depletion of inflammatory cells with cyclophosphamide or the administration of an MBP antibody or a neurokinin-1 (NK(1)) receptor antagonist (SR-140333) all prevented substance P-induced M(2) dysfunction and hyperreactivity. Intravenous heparin acutely reversed M(2) receptor dysfunction and hyperreactivity. Thus substance P releases MBP from eosinophils resident in the lungs by stimulating NK(1) receptors. Substance P-induced hyperreactivity is mediated by blockade of inhibitory neuronal M(2) receptors by MBP, resulting in increased release of acetylcholine.

A student-directed community project to support sexually abused women veterans suffering from post-traumatic stress disorder

While awareness of post-traumatic stress disorder (PTSD) and sexual abuse continues to grow, it has only been during the past few years that the military has realized the prevalence and impact of sexual abuse inflicted upon women while on active military duty. Though Veteran Administration (VA) agencies throughout the United States have given concerted attention to this problem, published resources specific to PTSD and military sexual abuse have been limited. In this article the authors present the results of a 2(1/2)-year endeavor to address the problem of PTSD and military sexual abuse at the Tulsa VA Outpatient Clinic. The project started with a research study and the subsequent initiation of a PTSD women veterans support group, and culminated in the development of resource manuals for both professional staff and women veterans.

Antigen-induced hyperreactivity to histamine: role of the vagus nerves and eosinophils

M2 muscarinic receptors limit acetylcholine release from the pulmonary parasympathetic nerves. M2 receptors are dysfunctional in antigen-challenged guinea pigs, causing increased vagally mediated bronchoconstriction. Dysfunction of these M2 receptors is due to eosinophil major basic protein, which is an antagonist for M2 receptors. Histamine-induced bronchoconstriction is composed of a vagal reflex in addition to its direct effect on airway smooth muscle. Because hyperreactivity to histamine is seen in antigen-challenged animals, we hypothesized that hyperreactivity to histamine may be due to increased vagally mediated bronchoconstriction caused by dysfunction of M2 receptors. In anesthetized, antigen-challenged guinea pigs, histamine-induced bronchoconstriction was greater than that in control guinea pigs. After vagotomy or atropine treatment, the response to histamine in antigen-challenged animals was the same as that in control animals. In antigen-challenged animals, blockade of eosinophil influx into the airways or neutralization of eosinophil major basic protein prevented the development of hyperreactivity to histamine. Thus hyperreactivity to histamine in antigen-challenged guinea pigs is vagally mediated and dependent on eosinophil major basic protein.

Pretreatment with antibody to eosinophil major basic protein prevents hyperresponsiveness by protecting neuronal M2 muscarinic receptors in antigen-challenged guinea pigs

In antigen-challenged guinea pigs there is recruitment of eosinophils into the lungs and to airway nerves, decreased function of inhibitory M2 muscarinic autoreceptors on parasympathetic nerves in the lungs, and airway hyperresponsiveness. A rabbit antibody to guinea pig eosinophil major basic protein was used to determine whether M2 muscarinic receptor dysfunction, and the subsequent hyperresponsiveness, are due to antagonism of the M2 receptor by eosinophil major basic protein. Guinea pigs were sensitized, challenged with ovalbumin and hyperresponsiveness, and M2 receptor function tested 24 h later with the muscarinic agonist pilocarpine. Antigen-challenged guinea pigs were hyperresponsive to electrical stimulation of the vagus nerves compared with controls. Likewise, loss of M2 receptor function was demonstrated since the agonist pilocarpine inhibited vagally-induced bronchoconstriction in control but not challenged animals. Pretreatment with rabbit antibody to guinea pig eosinophil major basic protein prevented hyperresponsiveness, and protected M2 receptor function in the antigen-challenged animals without inhibiting eosinophil accumulation in the lungs or around the nerves. Thus, hyperresponsiveness is a result of inhibition of neuronal M2 muscarinic receptor function by eosinophil major basic protein in antigen-challenged guinea pigs.

Stingray hickey

A large number of injuries from stingrays are reported each year in the United States. Usually these injuries are inflicted by the stingray's tail, after the resting stingray is stepped on. The tail has a stinger that can cause puncture wounds with envenomation. We report a case in which an injury from a stingray was due to its bite.

Supporting future surgical innovation. Lung transplantation as a case study

OBJECTIVE

Using lung transplantation as a case study, this article addressed the problem of supporting innovative clinical surgery in an era of increasing pressures for cost containment.

SUMMARY BACKGROUND DATA

After sporadic attempts at lung transplantation during the 1960s and 1970s, its clinical development began in earnest during the early 1980s. As a result of a wide range of incremental advances, the results have improved significantly. The Health Care Financing Administration, however, has not yet issued a national policy covering lung transplants and has left the coverage decision to the discretion of its regional contractors.

METHODS

The authors surveyed the major commercial insurers, the Blue Cross Blue Shield Association, and a sample of Medicare intermediaries to evaluate the coverage of lung transplantation. They also interviewed the National Heart, Lung, and Blood Institute and industrial firms about their support for clinical research.

RESULTS

Government and industry funding were limited, and the development and assessment of lung transplants have been financed predominantly by academic institutions through cross-subsidization from patient care and teaching funds. The major private payers and Blue Cross Blue Shield decided to cover this procedure in the early 1990s. Coverage decisions by Medicare intermediaries, however, revealed considerable variability. Moreover, the absence of a specific diagnosis-related group for lung transplants had considerable consequences for institutions in all-payer states, in which payments appeared to be considerably lower than the mean costs of a transplant procedure (about $110,000).

CONCLUSIONS

This analysis indicated that there was a growing disparity between the increasing demand for outcomes data about new procedures and the limited resources available for supporting the development and assessment of new operations. It this disparity is not addressed, the rate of surgical innovation may be jeopardized, and timely outcomes data may not be acquired. It was concluded that provisional coverage within a predetermined research protocol may be a promising mechanism to remedy this situation, providing timely assessment of new procedures before widespread application.

Activation of lamina propria T cells induces crypt epithelial proliferation and goblet cell depletion in cultured human fetal colon

An organ culture model has been used to study the effects of T cell activation in the human colon. Lamina propria T cells in explant cultures of human fetal colon (11 to 23 weeks gestation) were activated in situ using pokeweed mitogen or an anti-CD3 monoclonal antibody, and compared with unstimulated controls. After three days of culture, there was a two to four-fold increase in crypt epithelial cell proliferation in T cell stimulated explants of more than 15 weeks gestation, associated with a fall in crypt goblet cell numbers of up to 20-fold. By three days, the surface epithelium of stimulated explants appeared thin with loss of goblet cells, and by day 7, severe and extensive mucosal damage was observed by light and electron microscopy. These changes did not occur in control cultures and explants deficient in T cells (less than 16 weeks gestation), and were inhibited by cyclosporin A. These experiments indicate that the increase in epithelial cell proliferation and accompanying goblet cell depletion observed in colorectal crypts in chronic inflammatory bowel disease may be mediated by activated T cells.

Nursing salaries: a new strategy

Salary inconsistencies in the nursing department of the Mecklenburg Medical Group were becoming a significant problem. This case study explains how the group implemented a system to bring nurses' salaries in line with the rest of the community.

Three hundred sixty-five days post-HMO

Carolina Medical Care was conceived as a physician-owned HMO. Two-and-a-half years later, it was declared insolvent and shut down. As a founding member of the HMO, a third of its 15,000 patients were capitated to the Mecklenburg Medical Group. This case study examines the efforts to keep those patients following dissolution of the HMO.

Screening impotence by home nocturnal tumescence self-monitoring

Twenty subjects complaining of impotence were assessed using nocturnal penile tumescence (NPT), neurological, vascular and hormonal analysis. Subjects undertook NPT in both home and hospital environments: 10 hospital first and 10 home first. There were high levels of agreement between diagnosis using NPT in the two conditions and diagnosis from the physiological tests. There was a high correlation of frequency of erections between the home and hospital conditions, together with a high consecutive night reliability when using the monitor in the home condition (r = .94, p = .001).

Surgery for Crohn's disease in childhood: influence of site of disease and operative procedure on outcome

Factors influencing outcome after surgery have been studied in 67 children requiring bowel resection or diversion of the faecal stream for Crohn's disease. Patients were divided into four groups on the basis of disease location at time of surgery, and mean follow-up was 4.5 years. All three children with panenteric disease (group 1) have relapsed. Best results were observed in cases with disease confined to the small bowel (group 2) and ileocaecal region (group 3), in whom surgery was followed by sustained remission in six out of seven and 24 out of 30 patients respectively. In the 27 children with colitis (group 4), results were mixed. Six of the seven patients who had staged colonic resections with a primary anastomosis relapsed, as did three out of four patients given a loop ileostomy to divert the faecal flow; in contrast, 15 out of 16 children who had a subtotal colectomy with ileostomy as the primary procedure have remained well, with only minor problems involving the rectal stump. An acceleration in growth velocity was observed during the first year after operation in 89 per cent of 40 children studied. Outcome after surgery for Crohn's disease in childhood depends mainly on disease location, but is influenced by the type of primary operation performed. In addition to symptomatic relief the principal early benefit of surgery is improved growth.

Disability insurance: merging group and individual policies

This case study explains how the Mecklenburg Medical group, after discovering a gap in the disability insurance for its physicians, followed through by negotiating a new plan which also covered non-physician employees.

Epidural versus general anaesthesia for elective caesarean section. Effect on Apgar score and acid-base status of the newborn

Elective Caesarean section deliveries over a 5-year period were studied to compare the effect of epidural block with general anaesthesia on the condition of the infant at birth. The Apgar score and umbilical arterial acid-base status were used as determinants of the latter. Epidural block was used in 139 (22.8%) mothers while 471 (77.2%) were performed under general anaesthesia. No babies in the epidural group were severely depressed (Apgar less than 4), compared with 6.2% in the general anaesthesia group. Only 4.3% of the epidural sections were moderately depressed (Apgar 4-6), compared with 15.4% of the others. These differences remained highly significant when infants of less than 2500 g were excluded, and when matched groups were compared. Mean umbilical arterial pH was similar within the two groups (pH 7.28), and was not consistent with asphyxia in almost 90% of the depressed infants. The findings suggest that general anaesthesia, rather than asphyxia or aortocaval compression, is responsible for most of the depressed infants born by elective Caesarean section. This may involve over 20% of babies delivered in this manner, so greater use of epidural block for elective Caesarean section is recommended. Further investigations are required to improve results with general anaesthesia.

Amoxycillin-clavulanic acid (Augmentin) antibiotic prophylaxis against wound infections in renal failure patients

A randomized, controlled trial of the use of amoxycillin with clavulanic acid (Augmentin) for prophylaxis against wound infections following major surgery, including transplantation, in patients with chronic renal failure, was undertaken. Six of 22 control patients developed wound infections (27%) whereas no patient in the treatment group (24) developed a wound infection (P less than 0.05). After the termination of this trial, the next 35 consecutive patients received prophylactic amoxycillin/clavulanate; of these only two developed wound infections associated with leakage from their pancreatic anastomoses. All the wound infections were shown to be caused by bacteria sensitive to amoxycillin/clavulanate. Pharmacokinetic studies in patients have shown that a bactericidal concentration of the drugs was present for up to 20 h post-operatively in patients on dialysis, and in recipients of non-functioning renal transplants. In patients with normal renal transplant function excretion of the drug within 12 h was observed.

Bulbocavernosus reflex latency in the investigation of diabetic impotence

Impotence in males is a well recognised complication of diabetes mellitus, commonly held to be due to an autonomic neuropathy. The aim of this study was to determine the incidence of periphero-conus neuropathy in diabetic impotence. Nineteen diabetic males seeking treatment for loss of potency had bulbocavernosus reflex latency (BCRL) and sacral reflex latencies (SRLs) performed. The conduction studies indicated that impotence in these cases was associated with peripheral neuropathy in 21% of patients and that BCRL and SRLs are sensitive and useful diagnostic tests.

Response of the normal human ankle joint to imposed sinusoidal movements

Ankle joints were subjected to sinusoidal movements at a range of amplitudes and frequencies. Records were made of electromyograms (e.m.g.s) in calf muscles, and of the forces at the joints. When the leg is relaxed, the ankle joint resists an imposed sinusoidal movement with a small approximately sinusoidal force. It is stiffer in its resistance to small movements than to large ones, and this resistance is greater when the joint is dorsiflexed than when it is plantarflexed. If the subject exerts a steady mean flexing force, the imposed sinusoidal movement generates reflex activity which may be recorded as a modulation of the gastrocnemius and soleus e.m.g.s. The e.m.g. response to the sinusoidal movement occurs later in cycles of movement at high than at low frequencies, as one could expect of a reflex pathway that involves a delay. The results suggest that this delay is between 50 and 60 ms, and we conclude that under these circumstances spinal stretch reflexes are playing the important part. The relation of the resisting force to the movement has been displayed as a vector. As the frequency changes, this vector describes the circular path that is characteristic of a system which includes delays or lags; this path enables one to draw conclusions about the amplitude and timing of the reflex resistance to the movement. When a subject exerts a moderate flexing force against the sinusoidal movement for some minutes, the reflex response becomes progressively potentiated. A subject whose reflex responses are normally slight may then exhibit a vigorous reflex response to the movement of that ankle. This enhancement of spinal reflex activity was accompanied by an increase in the myotatic reflex response at the ankle. Reflex responses to sinusoidal movement were most clearly seen when the subject exerted a mean flexing force that amounted to about one-fifth of his maximum. Very small movements (+/- 0.5 degrees) generated little or no reflex response. With large amplitudes of movement there was more reflex activity, but at some amplitude (which varied from subject to subject and from time to time) the reflex mechanism appeared to 'saturate', and further increases in amplitude were not accompanied by comparable increases in the reflex response. With movements at 10-15 Hz the e.m.g. response often became large in alternate cycles, with less activity in the intervening cycles.(ABSTRACT TRUNCATED AT 400 WORDS)

The importance of urodynamic investigation following spontaneous rupture of the bladder

We report a case of spontaneous intraperitoneal rupture of the bladder. Followup urodynamic studies revealed unsuspected detrusor bladder neck dyssynergia that was treated by unilateral endoscopic bladder neck incision. The pathogenesis of spontaneous bladder rupture is discussed and we recommend urodynamic evaluation in all cases of spontaneous rupture.

Production of tolerance and physical dependence in the rat by simple administration of morphine in drinking water

1 Rats are capable of consuming solutions of morphine sulphate in drinking water ad libitum in the absence of taste-masking chemicals and without the need for scheduled provision or prior parenteral administration of the drug. 2 The success of this method depends on the initial provision of a 0.1 mg/ml solution of morphine sulphate. 3 When the drug concentration is increased to 0.4 mg/ml, the rats achieve an average daily intake of 50 mg/kg body wt. each. 4 Daily intake of morphine may be increased by at least about three fold by increasing the drug concentration to 1.2 mg/ml. 5 Oral morphine administration causes only a moderate loss in body weight. 6 Rats whose daily intake of the drug is 50 mg/kg exhibit tolerance to the analgesic action of morphine and show a drastic loss in body weight at 24 h after withdrawal and most of the behavioural symptoms of the naloxone-precipitated withdrawal syndrome. 7 It is suggested that this simple method of morphine administration is suitable for further biochemical and behavioural studies of the actions of the drug.

Critical evaluation of direct vision urethrotomy by urine flow measurement

Fifty-two male patients were studied prospectively to assess the results of direct vision urethrotomy in the treatment of urethral strictures. The prognosis was found to be significantly worse in those patients who had received extensive previous treatment. A catheter is recommended for at least 3 days and for 4 weeks in patients who have had minimal previous treatment or who have impaired detrusor function. The use of a urine flowmeter is essential for determining the success of treatment and stricture recurrence. Measurement of the recurrence-free period is important for assessing progressive improvement following repeat urethrotomy and for determining which patients cannot be cured by direct vision urethrotomy.

Alternate approach to the analysis of solar photometer data

The standard technique of analyzing solar photometer data to determine atmospheric optical depth and the spectral solar constant is shown to inadvertently weight the data unequally. A new approach is proposed which equally weights all the data. Assuming that the deviations of the data points result from real random variations of optical depth during the period of the measurements, this latter approach is shown to yield more reliable results.

Cystic fibrosis and the month of birth

A bimodal birth distribution and seasonal trend has been previously reported in cystic fibrosis. The present study of 412 cases in Manchester and Bristol does not confirm the presence of a seasonal trend or any cyclic variation, and in general the trends in the present study are the reverse of those in the previous reports.

Inhibition of rat brain tryptophan metabolism by ethanol withdrawal and possible involvement of the enhanced liver tryptophan pyrrolase activity

1. Chronic ethanol administration to rats was previously shown to enhance brain 5-hydroxytryptamine synthesis by increasing the availability of circulating tryptophan to the brain secondarily to the NAD(P)H-mediated inhibition of liver tryptophan pyrrolase activity. 2. At 24h after ethanol withdrawal, all the above effects were observed because liver [NAD(P)H] was still increased. By contrast, all aspects of liver and brain tryptophan metabolism were normal at 12 days after withdrawal. 3. At 7--9 days after withdrawal, brain 5-hydroxytryptamine synthesis was decreased, as was tryptophan availability to the brain. Liver tryptophan pyrrolase activity at these time-intervals was maximally enhanced. 4. Administration of nicotinamide during the withdrawal phase not only abolished the withdrawal-induced enhancement of tryptophan pyrrolase activity on day 8, but also maintained the inhibition previously caused by ethanol. Under these conditions, the withdrawal-induced decreases in brain 5-hydroxytryptamine synthesis and tryptophan availability to the brain were abolished, and both functions were enhanced. Nicotinamide alone exerted similar effects in control rats. 5. It is suggested that ethanol withdrawal inhibits brain 5-hydroxytryptamine synthesis by decreasing tryptophan availability to the brain secondarily to the enhanced liver tryptophan pyrrolase activity. 6. The results are discussed in relation to the possible involvement of 5-hydroxytryptamine in dependence on ethanol and other drugs.

A controlled trial of different treatment regimens in patients with urinary tract infections after lower urinary tract surgery

One hundred and four patients who developed urinary tract infections after catheterization for acute retention of urine and surgery of the bladder or urethra were randomly allocated to four treatment groups. Analysis of the results in 65 patients showed that co-trimoxazole and 1 g cephradine administered twice daily for 1 week were successful in eradicating the urinary tract infections in 93% and 88% of the patients, respectively. The same dose of cephradine administered 4-times a day eradicated 64% of the infections. In patients for whom no treatment was given, the original infection did not clear in 65%. Escherichia coli and coagulase-negative staphylococci were the commonest infecting organisms. The in vitro sensitivity testing of antibiotics did not correlate well with the successful eradication of the infecting organism.

Traffic of lymphocytes in the thoracic duct and renal lymph after allotransplantation and in immunosuppression

A marked rise is seen in the number of white blood cells in the lymph leaving the sheep kidney after allografting; the number of lymphocytes leaving the kidney rising in direct relation to the degree of damage from acute rejection. No such rise is demonstrable in the number of lymphocytes in the thoracic duct lymph of sheep with rejecting kidney allografts. Indeed, there is an apparent decrease in the number of lymphocytes in the thoracic duct lymph of sheep with rejecting kidney allografts. Indeed, there is an apparent decrease in the number of circulating lymphocytes in the body when acute rejection is fully developed. Animals on immunosuppressive regimens show no alteration in the number of lymphocytes collected on thoracic duct cannulation, but immunosuppression appears to reduce the lymphocyte traffic through the kidney.

The value of provocative and acute urography in patients with intermittent loin pain

Twenty-two patients with intermittent loin pain thought to be typical of primary pelvic hydronephrosis but with normal appearances at standard excretion urography were subjected to diuretic urography using Frusemide-induced diuresis. If this was normal, acute urography was performed when the patient had pain. Abnormal appearances were shown in only 15 patients. In 4, only the erect films revealed the hydronephrosis. Dilatation occurred in response to a diuretic load in 9 and the abnormality was shown at the time of an attack of pain in 4. The hydronephrosis was shown only during the attack of pain in 2, a diuretic urogram having been normal. In 2 patients the nephrographic signs of acute obstruction were shown to be due to occlusion of the pelvi-ureteric junction at the time of an attack of pain. The importance of sequential examination, the value of erect films and acute urography are stressed.