Are Surgeons Going to Be Left Holding the Bag? Incisional Hernia Repair and Intra-Peritoneal Non-Absorbable Mesh Implant Complications

Ventral incisional hernias are common indications for elective repair and frequently complicated by recurrence. Surgical meshes, which may be synthetic, bio-synthetic, or biological, decrease recurrence and, resultingly, their use has become standard. While most patients are greatly benefited, mesh represents a permanently implanted foreign body. Mesh may be implanted within the intra-peritoneal, preperitoneal, retrorectus, inlay, or onlay anatomic positions. Meshes may be associated with complications that may be early or late and range from minor to severe. Long-term complications with intra-peritoneal synthetic mesh (IPSM) in apposition to the viscera are particularly at risk for adhesions and potential enteric fistula formation. The overall rate of such complications is difficult to appreciate due to poor long-term follow-up data, although it behooves surgeons to understand these risks as they are the ones who implant these devices. All surgeons need to be aware that meshes are commercial devices that are delivered into their operating room without scientific evidence of efficacy or even safety due to the unique regulatory practices that distinguish medical devices from medications. Thus, surgeons must continue to advocate for more stringent oversight and improved scientific evaluation to serve our patients properly and protect the patient-surgeon relationship as the only rationale long-term strategy to avoid ongoing complications.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

In vitro measurement of internal hoof strain

REASONS FOR PERFORMING STUDY

Strains during stance on the hoof wall surface have been measured by a number of authors in vitro and in vivo. Histological structure and mechanical properties vary through the wall thickness (radially); radial strain measurements may therefore aid the understanding of mechanical function of the capsule and adjacent tissues.

OBJECTIVES

To develop instrumentation capable of measuring internal hoof strain, and to carry out a preliminary comparison of normal and laminitic hooves.

METHODS

Six forelimbs from 4 horses, including 2 with laminitis from the same horse, were tested using an Instron test rig designed to simulate the walk at impact, midstance and breakover. Internal strains were measured at a dorsal site using strain gauges moulded into a plug made of 007 fast-set structural adhesive. In addition, kinetic and kinematic data were collected from each specimen.

RESULTS

When simulating the walk, a significant (P<0.0001) increase in gradient of radial tensile strain was found in a normal hoof wall, from 5.6 +/- 73.9 microepsilon at the outer gauge to 418.5 +/- 170.6 microepsilon at the inner gauge. However, radial strains measured at the inner gauge site in limbs with laminitis were found to be significantly (P<0.0001) compressive, with values of -406.7 +/- 156.3 and -109.9 +/- 72.4 microepsilon for Specimens 1 and 2, respectively.

CONCLUSIONS AND POTENTIAL RELEVANCE

These preliminary data indicate that a marked redistribution may well occur in the wall of laminitic hooves. With a larger sample size, the results should have relevance to the treatment and management of laminitis.

Prevalence of type-specific HPV infection by age and grade of cervical cytology: data from the ARTISTIC trial

Human papillomavirus (HPV) infection causes cervical cancer and premalignant dysplasia. Type-specific HPV prevalence data provide a basis for assessing the impact of HPV vaccination programmes on cervical cytology. We report high-risk HPV (HR-HPV) type-specific prevalence data in relation to cervical cytology for 24 510 women (age range: 20–64; mean age 40.2 years) recruited into the ARTISTIC trial, which is being conducted within the routine NHS Cervical Screening Programme in Greater Manchester. The most common HR-HPV types were HPV16, 18, 31, 51 and 52, which accounted for 60% of all HR-HPV types detected. There was a marked decline in the prevalence of HR-HPV infection with age, but the proportion due to each HPV type did not vary greatly with age. Multiple infections were common below the age of 30 years but less so between age 30 and 64 years. Catch-up vaccination of this sexually active cohort would be expected to reduce the number of women with moderate or worse cytology by 45%, but the number with borderline or mild cytology would fall by only 7%, giving an overall reduction of 12% in the number of women with abnormal cytology and 27% in the number with any HR-HPV infection. In the absence of broader cross-protection, the large majority of low-grade and many high-grade abnormalities may still occur in sexually active vaccinated women.

Liquid-based cytology can improve efficiency of cervical smear readers: evidence from timing surveys in two NHS cytology laboratories

OBJECTIVE

Cervical screening programmes in England and Wales were advised by the National Institute for Clinical Excellence in 2003 to adopt liquid-based cytology (LBC) in place of conventional Papanicolaou (Pap) cytology to facilitate laboratory efficiency. Pilot evaluations in England and Scotland monitored daily or weekly workloads of smear readers and concluded that LBC could increase hourly throughput rates. This study, instead, used timing surveys to determine screening rates.

METHODS

Two National Health Service cytology laboratories in Manchester and Stockport were partially converted to the LBC ThinPrep process for a cervical screening trial. Three 1-week timing surveys were conducted over 7 months. The surveys covered all LBC-trained staff. The first survey in Manchester also covered staff undertaking conventional Pap screening. The smear readers used timers to record time taken for examining and reporting each slide.

RESULTS

In Manchester, in the first survey, nearly 1 minute per slide was saved by the LBC method during primary microscopy. In both laboratories, the mean microscopy time for primary screening of LBC slides was reduced by almost 1 minute between the first and second surveys. There was no difference between the second and third surveys. Microscopy by cytopathologists was also 1 minute per slide quicker with LBC than conventional Pap. The LBC inadequate rates for both laboratories were <2.0%. Organizational factors impacted on the hourly LBC primary screening rates in the laboratories, the rate for Stockport being higher than the rates in the pilot evaluations.

CONCLUSIONS

The timing surveys confirm that the LBC ThinPrep technology can improve laboratory efficiency. However, decision-makers should also consider the overall costs and benefits of introducing the technology in screening programmes, including the capital investment and workforce implications.

Tracing the first stars with fluctuations of the cosmic infrared background

The deepest space- and ground-based observations find metal-enriched galaxies at cosmic times when the Universe was less than 1 Gyr old. These stellar populations had to be preceded by the metal-free first stars, known as 'population III'. Recent cosmic microwave background polarization measurements indicate that stars started forming early--when the Universe was < or =200 Myr old. It is now thought that population III stars were significantly more massive than the present metal-rich stellar populations. Although such sources will not be individually detectable by existing or planned telescopes, they would have produced significant cosmic infrared background radiation in the near-infrared, whose fluctuations reflect the conditions in the primordial density field. Here we report a measurement of diffuse flux fluctuations after removing foreground stars and galaxies. The anisotropies exceed the instrument noise and the more local foregrounds; they can be attributed to emission from population III stars, at an era dominated by these objects.

Does crew resource management training work?

INTRODUCTION

Effective crew resource management (CRM) may play a major role in decreasing the number of accidents and increasing overall safety of air medical programs. The purpose of the study was to compare the responses of crew members, in a variety of situations, who received CRM training and those who did not. The numerical results of the responses were used to evaluate the effectiveness of CRM in increasing crew awareness and promoting team concepts.

METHOD

During a 12-month period, crew members of randomly selected air medical programs (fixed- and rotor-wing) were surveyed by questionnaire. Participants were asked if they had received CRM, effective communication, and team-building training. The next 15 questions pertained to crew interaction/communication in everyday and emergent situations and were scored on a Likert scale (1 = strongly agree and 5 = strongly disagree). A lower total score indicated a greater understanding of team awareness and effective communication.

RESULTS

The mean score of crew members who received the three identified areas of training (initial CRM, team-building, effective communications) (37.96, SD +/- 7.67) was found to be significantly lower than the mean score of those who had received none of the training (44.13, SD +/- 5.0) and P < .05.

CONCLUSION

Based on the results, CRM training increases crew awareness and promotes team concepts in both everyday and emergent situations.

Efficacy of community-based second trimester genetic ultrasonography in detecting the chromosomally abnormal fetus

We sought to assess prospectively the efficacy of community-based genetic ultrasonography in detecting chromosomally abnormal fetuses in a high-risk population and determine independent markers of aneuploidy. Patients 18 years old and older who were between 14 and 24 weeks' gestation were included if referred for maternal age greater than 35 years, increased risk of Down syndrome or trisomy 18 by second trimester serum screen, or prior affected offspring. All women had a targeted ultrasonographic examination between April 1997 and June 1999 and were offered fetal chromosomal analysis. Markers of aneuploidy and pregnancy outcomes were recorded prospectively. The primary outcome was prenatally or postnatally detected chromosomal abnormalities. Of the 1030 fetuses seen during the study, 789 had outcome data available and constituted the study group. In this group, 694 (87.9%) ultrasonograms were normal, 73 (9.2%) had one marker present, 17 (2.2%) had two markers present, and 5 (0.6%) had three or more markers present. Fourteen of 17 (82.3%) aneuploid fetuses had an abnormal ultrasonogram (one or more markers present), including 5 of 7 (71.4%) with Down syndrome. Logistic regression showed abnormal four-chamber view, structural anomaly, and intracardiac echogenic focus to be significant aneuploidy markers. The amniocentesis rate was 334 of 1030 (32.4%), and it increased with the number of sonographic markers noted (0 = 29.9%, 1 = 60.2%, 2 = 70.6%, 3 or more = 80%). Genetic ultrasonography is highly effective in identifying chromosomally abnormal fetuses in a community-based practice.

Cost-utility analysis of second-line hormonal therapy in advanced breast cancer: a comparison of two aromatase inhibitors to megestrol acetate

Randomized trials comparing the aromatase inhibitors, anastrozole and letrozole, to megestrol acetate (MA) in postmenopausal women with advanced breast cancer demonstrated that both agents are better tolerated than MA with comparable efficacy. In addition, one trial revealed that tumor response and time to treatment failure were significantly better with letrozole. Since oncologists are faced with a choice between three agents with at least comparable efficacy but different toxicity profiles and cost, a cost-utility analysis was conducted to quantify these differences and to determine if the new agents are more cost-effective than MA. In the absence of a randomized three-arm trial, a decision model was developed to simulate the most common therapeutic outcomes. The clinical data were obtained from an overview analysis of randomized trials. Total hospital resource consumption was collected from 87 patients with advanced disease that had failed second-line hormonal therapy. Utility estimates were obtained from interviewing a random sample of 25 women from the general public and 25 female health care professionals using the Time Trade-Off technique. The model suggested a similar duration of quality-adjusted progression-free survival between drugs (letrozole 150 days, anastrozole 153 days and MA 146 days). Letrozole had an overall cost of Can$2949 per patient which was comparable to MA at Can$2966 per patient. In contrast, anastrozole was slightly more costly than MA at $Can3149 per patient, respectively. The analysis revealed that letrozole has comparable overall costs relative to MA while providing at least equivalent quality-adjusted progression-free survival. These outcomes were largely related to its higher tumor response rate, which translated to a lower proportion of patients requiring chemotherapy. Anastrozole was slightly more costly than MA and did not demonstrate superiority in quality-adjusted progression-free survival in this palliative setting.

A preliminary study of sonographic grading of fetal intracardiac echogenic foci: feasibility, reliability and association with aneuploidy

OBJECTIVES

To prospectively and quantitatively grade intracardiac echogenic focus/foci (ICEF) using sonographic gain reduction and to determine the association of ICEF by grade with fetal aneuploidy.

METHODS

Women referred for raised maternal age (> or = 35 years), or > 18 years of age and with a Down syndrome risk > or = 1/270, increased trisomy 18 risk by second trimester serum screen or a prior aneuploid offspring were included in this institutionally approved protocol. Only pregnancies of gestational age between 14 and 24 weeks were included. All women had a targeted ultrasound and were offered fetal chromosome analysis. The classification of ICEF was made from a four-chamber view of the fetal heart. The echo amplitude of the ICEF was compared to that of the thoracic spine and categorized according to the comparative gain setting at which the image of the relevant structure disappeared: Grade O = no ICEF present, Grade 1 = ICEF image lost before thoracic spine when gain was reduced, Grade 2 = ICEF image lost at same gain setting as thoracic spine, Grade 3 = thoracic spine image lost before ICEF. The primary outcome was a prenatally or post-natally detected chromosomal abnormality.

RESULTS

A total of 885 eligible women were examined during the 21-month study period. ICEF were seen in 29 (3.3%) fetuses: 24(83%) in the left ventricle and five (17%) in the right ventricle. A chromosome abnormality was identified in 13/671 (1.9%) fetuses without ICEF (Grade 0) and 0/21 (0%) fetuses with Grade 1 ICEF. In contrast, two of five (40%) fetuses with Grade 2 ICEF were aneuploid (P = 0.005). No Grade 3 ICEF were observed. Additional sonographic abnormalities were seen in both aneuploid fetuses with Grade 2 ICEF. Interobserver agreement on ICEF grading was noted in 50/50 (100%) examinations (kappa = 1.0).

CONCLUSIONS

Sonographic grading of ICEF is feasible and highly reliable. Grade 2 ICEF, especially when accompanied by additional sonographic markers of a chromosomal abnormality, are associated with aneuploidy significantly more frequently than Grade 1 ICEF.

Fetal intracardiac echogenic foci: current understanding and clinical significance

The detection of fetal intracardiac echogenic foci (ICEF) by ultrasound was first reported in 1987. Despite many investigations, the relationship of ICEF with congenital heart malformations and chromosomal abnormalities remains unclear. This review describes the current understanding of ICEF based on a literature search from 1980 to the present. ICEF are observed in 0.5 to 20 percent of fetuses, with an overall frequency of 5.6 percent. These small, discrete structures near the papillary muscles and chordae tendinae move in synchrony with the intraventricular valves. They likely represent microcalcification of the papillary muscles. ICEF are most commonly seen in the left ventricle and occasionally in the right ventricle or bilaterally. Intra-atrial or diffuse ICEF are rare. In the chromosomally normal fetus, ICEF are not associated with congenital heart defects. The presence of ICEF in fetuses at high risk for chromosomal abnormalities suggests an increased possibility of aneuploidy, especially if other sonographic markers are noted. A similar association is observed with trisomy 21 in particular. The significance of ICEF in fetuses at low risk for aneuploidy is less clear and represents an area for future research.

Twin vaginal birth after cesarean

OBJECTIVE

To determine both success rate and maternal-fetal outcome of vaginal birth after cesarean in twin gestations.

METHODS

We identified all women from a single center attempting vaginal birth of twins after cesarean from 1988-98. Twin pairs were excluded for delivery < or = 25 weeks gestation, monoamnionicity, nonvertex twin A, or major anomaly or death of either twin. Cases were matched to the next three consecutive twin gestations attempting vaginal delivery without a prior cesarean. Variables matched were gestational age at delivery (+/- 1 week), presentations of both fetuses, labor onset (spontaneous or induced), and prior vaginal delivery (yes or no). The primary outcome was successful vaginal delivery of both fetuses. Secondary maternal outcomes included chorioamnionitis, hemorrhage requiring transfusion, hysterectomy, uterine rupture, and length of stay. Neonatal outcomes included one and five minute Apgars, NICU admission, and length of NICU stay.

RESULTS

Twelve parturients were matched to 36 controls. There were no differences between the groups with respect to maternal demographics, intrapartum variables, fetal genders, birthweights, or chorionicity. Women with a prior cesarean (10/12) delivered both twins vaginally compared to 31/36 parturients without a prior cesarean (P = 1.0). There were no differences between cases and controls with respect to maternal morbidity (1/12 vs 4/36, P = 1.0), or postpartum stay (2.5 +/- 1.0 vs 2.5 +/- 2.3 days, P = .25). Neonatal outcomes were similar by birth order, except that second-born twins of cases had significantly longer NICU stays than controls (22.7 +/- 3.8 vs 10.4 +/- 7.8 days, P = .04).

CONCLUSION

Twin trial of labor after cesarean is associated with a high success rate of vaginal delivery but may be associated with a more lengthy NICU stay for the second twin.

Effectiveness of a writing improvement intervention program on the readability of the research informed consent document

BACKGROUND

Problems with the comprehensibility of human research informed consent have been documented since the 1970s, and efforts aimed at rewriting consents have not been successful in consistently producing more readable consents. This study employed researched principles of reading comprehension research to create writing intervention program designed to help the research writer produce more comprehensible informed consent documents. The purpose of this study was to determine if this intervention program was effective.

METHOD

The key component of the writing improvement intervention packet was a newly formatted consent form that contained annotated instructions for researchers on how to write each section for optimum comprehension. The resulting consent forms were evaluated using a Readability and Processability Form (RPF). The RPF is based on reading research and includes the Fry Scale, which yields an approximate grade reading level. The RPF assigned points to each of the 20 areas of comprehension analysis according to strict scoring criteria, and target scores were established by the authors in consultation with the hospital institutional review board.

RESULTS

We evaluated 66 post-intervention informed consents. The mean readability and processability score was 62, resulting in the RPF classification of "good." The established readability and processability target range was good to excellent or 61-100 points; 66% of the forms scored in this range. In our 1995 pre-intervention study, the corresponding score was 12%. The target range for grade reading level was 8th grade: 53% scored in that range as compared with 4% in 1995. A question-by-question analysis of each of the 20 checklist items on the RPF identified important aspects of the consent writing that improved and others that were still weak and needed improvement.

CONCLUSIONS

The Hartford Hospital writing improvement intervention program was associated with the production of more comprehensible informed consent documents. Using the intervention materials, investigators from a variety of departments could function independently to produce readable consent forms. This program may help others who wish to assist their research departments in creating consents that are written for optimal reading comprehension.

Receptor binding and biological activity of mammalian expressed sensory and motor neuron-derived factor (SMDF)

Sensory and motor neuron-derived factor (SMDF) is a member of the neuregulin family of proteins. SMDF is structurally characterized by a novel N-terminal domain. Using the signal sequence and N-terminal 28 amino acids (the "epitope") of herpes simplex virus type 1 glycoprotein D (gD), we have expressed SMDF as an epitope-tagged protein (gD-SMDF) in 293 cells, and purified it to > 98% homogeneity on a monoclonal anti-gD column. gD-SMDF stimulates human Schwann cell growth and 3H-thymidine incorporation in MCF-7 and T47D human breast tumor cells in vitro. The biological activity of gD-SMDF is consistent with its ability to compete with 125I-labeled heregulinbeta1 peptide (rHRGbeta1(177-244)) to bind to soluble dimeric ErbB receptor-IgG fusion proteins. gD-SMDF binds with low affinity to homodimeric ErbB3-IgG and ErbB4-IgG but with higher affinity to heterodimeric ErbB2/ErbB3-IgG and ErbB2/ErbB4-IgG. Using a SMDF-IgG(Fc) fusion protein we generated a monoclonal antibody (3G11) which binds SMDF, crossreacts with rHRGbeta1(177-244), and neutralizes the in vitro activities of gD-SMDF and rHRGbeta1(177-244) in human Schwann cells.

The role of cultured Schwann cell grafts in the repair of gaps within the peripheral nervous system of primates

With recent advances in cell culture techniques it is possible to isolate human SCs from adult peripheral nerves, expand and purify their number in cell culture, and construct a cellular prosthesis from the cultured cells. The current study was designed to ascertain whether these techniques could be used to repair nonhuman primate nerve injuries. In 12 adult female cynomologous monkeys, the musculocutaneous (msk) nerve was divided and prevented from regenerating and the brachioradialis nerve (brach) was exposed bilaterally (n = 24 nerves) and injured so that a 15-mm gap existed within the nerve. The brach nerves were either repaired with sural nerve autografts (n = 6), guidance channels which contained monkey SCs (120 x 10(6) cells/ml; n = 6), or guidance channels without SCs (n = 6). The remaining brach nerves (n = 6) had either no injury or an injury to the nerve without a repair. Autologous expanded primate SCs were increased in number at least 10-fold over a 2-week period at which time the SC purity exceeded 99.9%. Monkeys in each group, including the control group, regained some degree of elbow flexion after 3 months despite sectioning both the mask nerve and the brach nerve; therefore, we were unable to determine simply on clinical grounds which repair was the most effective in promoting functional recovery. Brach nerves repaired with sural nerve grafts were superior to both the channels which contained SCs and empty channels in regards to the number of myelinated axons proximal, within, and distal to the repair site (P < 0.05). Electrophysiologic results closely paralleled the histologic data with evidence of reinnervation of the brachioradialis muscle based on the compound muscle action potential in both sural nerve graft and monkey SC channel repair groups.

Activin signaling through activin receptor type II causes the cachexia-like symptoms in inhibin-deficient mice

Activins and inhibins, members of the transforming growth factor-beta superfamily, are involved in diverse physiological and developmental processes. We have previously shown that mice deficient in alpha-inhibin develop gonadal sex cord-stromal tumors at an early age. The tumor development is rapidly followed by a wasting syndrome that includes severe weight loss, hepatocellular necrosis around the central vein, and depletion of the parietal cells in the glandular stomach. The liver histology in inhibin-deficient mice is similar to the pathological effects of short-term treatment of rats and mice with recombinant activin A. Consistent with these findings, we have shown that the gonadal tumors in the inhibin-deficient mice secrete high levels of activins. In addition, Northern blot analysis has localized activin receptor type II (ActRII) to the liver. Based on these studies, we postulated that tumor-produced activins act through ActRII to cause the wasting syndrome in inhibin-deficient mice. To test this hypothesis and determine the significance of elevated levels of activin signaling through ActRII in vivo, we generated compound homozygous mutant mice deficient in both alpha-inhibin and ActRII. Despite the continued development of gonadal sex cord-stromal tumors and elevated serum levels of activin A and B, the compound homozygous mutant mice suffered no unusual weight loss, and the stomachs and livers of the majority of the mice were histologically normal. These results demonstrate that increased levels of activin signaling through ActRII in hepatocytes and the glandular stomach causes the hepatocellular necrosis and depletion of parietal cells in the glandular stomach as well as the severe weight loss in vivo.

Testicular germ cell populations in the adult rat after continuous in-vivo testicular infusion of inhibin-A and activin-A

This study investigated the in-vivo effects of inhibin-A and activin-A on germ cell subpopulations in the adult rat testis. Each animal received a total of 2 micrograms (dose 5 ng/0.5 microliter/h) of activin, inhibin or 0.1% bovine serum albumin (vehicle control) delivered intratesticularly into the left testis via a cannula connected to an abdominal minipump implant. To establish whether the hormones exerted any effect on procarbazine-induced germ cell depletion, a single intraperitoneal dose of this agent was given to a group of the rats 24 h after the start of testicular infusion of activin or inhibin. Rats were killed 14 days later. Inhibin treatment caused a reduction in the number of round spermatids without altering serum FSH levels. In procarbazine-treated rats, infusion of inhibin reduced the number of pachytene spermatocytes and reduced blood FSH levels simultaneously. Infusion of activin had no significant effect on the numbers of germ cells, but reduced the number of dead cells in the seminiferous tubules of procarbazine-treated rats. The data would therefore suggest that the effects of inhibin and activin on the seminiferous epithelium are influenced by the testicular microenvironment, and that they are capable of influencing the growth and survival of germ cells by both FSH- and non FSH-mediated mechanisms. Further experiments are needed to identify the physiological role(s) of inhibin and activin in spermatogenesis.

Scheduled inspection of electromedical equipment. Planning and assessment

Scheduled inspections help ensure the safety and efficacy of medical equipment. To ensure the regular checking of all items we developed a practical and realizable protocol consisting of basic safety and functional tests. Non-productive time spent searching for equipment was reduced enlisting the help of ward staff. Record keeping was simplified using monthly checklists detailing the tests to be performed. Clear labels distinguished items checked and the ward was informed about missing items. The effectiveness of the programme was assessed by auditing the number of items due for inspection, the average time per inspection, the number of faults found, and the incidence of breakdown repairs. The average inspection time per item was reduced to half an hour and the number of items due for inspection to below 10%. The programme was effective in fault detection (7% of items checked) and the incidence of breakdown repairs decreased from 75 to 53%.

Retinal and preretinal localisation of epidermal growth factor, transforming growth factor alpha, and their receptor in proliferative diabetic retinopathy

A number of growth factors have been implicated in the development and perpetuation of preretinal fibrovascular membranes in patients with proliferative diabetic retinopathy (PDR). The aim of this study was to determine the potential role of epidermal growth factor (EGF), transforming growth factor alpha (TGF-alpha), and their receptor (EGF-R) in PDR development. Immunostaining for EGF, TGF-alpha, and EGF-R was compared between normal retina, PDR retina, and PDR preretinal membranes. Weak staining for EGF and EGF-R was observed throughout the neural retina from non-diabetic eyes while weak to moderate staining for TGF-alpha was observed in the ganglion cell layer and the inner and outer nuclear layers. In contrast, intense staining for EGF and TGF-alpha and moderate staining for EGF-R were observed throughout the PDR retina. Immunoreactivity for EGF, TGF-alpha, and EGF-R was seen in the majority of the 11 excised membranes studied and, though variable, was generally greater than that observed in normal retinas. These results suggest an autocrine/paracrine role for EGF, TGF-alpha, and EGF-R in PDR.

Quantitative two-site enzyme-linked immunosorbent assays for inhibin A, activin A and activin B

We have developed three specific enzyme-linked immunosorbent assay (ELISA) formats which quantitate inhibin A in conditioned media and serum. The assays are sensitive in a range 0.078-5.0 ng/ml and have been characterized in terms of cross-reactivity to inhibin related proteins. The CK:CK assay format recognizes inhibin A, inhibin B and inhibin-related molecules, while the 9A9:CK assay format recognizes inhibin A and inhibin A precursors, but not free alpha-subunit. The 11B5:CK assay appears to recognize only mature 32 kDa inhibin A. Additionally, we have developed separate, specific ELISA formats which quantitate activin A and activin B. The assays have a range of 0.2-50 ng/ml and 0.4-50 ng/ml for activin A and recombinant activin B, respectively. These assays are presently being used to examine the concentration of inhibin A, activin A and activin B in clinical serum samples.

Pharmacokinetic profile of recombinant human (rh) inhibin A and activin A in the immature rat. II. Tissue distribution of [125I]rh-inhibin A and [125I]rh-activin A in immature female and male rats

The tissue distribution of recombinant human inhibin A (rh-inhibin A) and rh-activin A was determined in immature female Sprague Dawley-derived rats after iv administration of radiolabeled proteins. [125I]rh-Inhibin A and [125I]rh-activin A diverge in their distribution to tissues of the immature female rat as examined histologically (whole body autoradiography and thin section analysis) and by computing the percent dose and tissue to blood ratios for individual tissues. [125I]rh-inhibin A accumulated in the spleen, adrenal, bone marrow, and ovary after iv injection. Iodinated rh-inhibin A was also found in the anterior and posterior pituitary. [125I]rh-activin A was found in the ovary and pituitary after iv injection. Little specific binding was found in the spleen or adrenal. The bone marrow accumulated some [125I]rh-activin A which was competed by rh-activin A. The primary route of excretion for radioactivity was the kidney, with the label appearing in the bladder by 10 min after iv injection. Not only do rh-inhibin A and rh-activin A have different pharmacokinetics, but fewer tissues accumulate radioactive rh-activin A than rh-inhibin A.

In vitro ligand binding of 125I-recombinant human activin A to the female rat brain

Activin has been localized within cells and terminals in the brain. However, little is known about the site of action of this hormone within the brain. In the present study in vitro ligand autoradiography was used to determine the distribution of high affinity binding sites for 125I-rh activin A in rat brain. The highest density of binding sites were concentrated in the amygdala and other forebrain limbic structures. Binding was saturable in selected amygdala nuclei with an apparent Kd of approximately 0.2 nM. 125I-rh activin A binds specifically in regions known to contain terminals immunoreactive for this hormone, and also at sites distinct from the location of activin A containing neuronal terminals (e.g. the ventral limbic system).

Characterization of recombinant human factor VIII

Recently, complete human factor VIII DNA clones have been obtained and subsequently expressed in baby hamster kidney cells (Wood, W. I., Capon, D. J., Simonsen, C. C., Eaton, D. L., Gitschier, J., Keyt, B., Seeburg, P. H., Smith, D. H., Hollingshead, P., Wion, K. L., Delwart, E., Tuddenham, E. G. D., Vehar, G. A., and Lawn, R. M. (1984) Nature 312, 330-337). The recombinant factor VIII (rVIII) protein secreted from these cells has now been purified allowing its structural analysis and comparison to plasma-derived factor VIII (pdVIII). Analysis of purified rVIII by sodium dodecyl sulfate-polyacrylamide gel electrophoresis shows that it consists of multiple polypeptides with relative mobilities (Mr) ranging from 80,000-210,000. The same pattern of polypeptides is also observed for pdVIII resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The proteins associated with rVIII are recognized by pdVIII antibodies in a Western blot. When rVIII and pdVIII are subjected to isoelectric focusing they are resolved into a similar pattern of protein bands. Thrombin, factor Xa, and activated protein C, which modulate factor VIII activity by proteolysis, process rVIII in the same manner they do pdVIII. As is the case for pdVIII, thrombin activation of rVIII coagulant activity correlates with the generation of subunits with Mr of 73,000, 50,000 and 43,000. These subunits appear to form a metal-(perhaps Ca2+) linked complex. EDTA inactivates thrombin-activated rVIII and pdVIII, with the activity being regenerated after the addition of a molar excess of MnCl2. The results suggest that rVIII is structurally and functionally very similar to pdVIII.

Construction and characterization of an active factor VIII variant lacking the central one-third of the molecule

The primary structure of factor VIII consists of 2332 amino acids that exhibit 3 distinct structural domains, including a triplicated region (A domains), a unique region of 909 amino acids (B domain), and a carboxy-terminal duplicated region (C domains), that are arranged in the order A1-A2-B-A3-C1-C2. The B domain (residues 741-1648) of factor VIII is lost when factor VIII is activated by thrombin, which proteolytically processes factor VIII to active subunits of Mr 50,000 (domain A1), 43,000 (domain A2), and 73,000 (domains A3-C1-C2). To determine if the B domain is required for factor VIII coagulant activity, a variant was constructed by using recombinant DNA techniques in which residues 797-1562 were eliminated. This shortened the B domain from 909 to 142 amino acids. This variant factor VIIIdes-797-1652 was expressed in mammalian cells and was found to be functional. The factor VIIIdes-797-1562 protein was purified and shown to be processed by thrombin in the same manner as full-length factor VIII. The factor VIIIdes-797-1562 variant also bound to von Willebrand factor (vWF) immobilized on Sepharose. These results indicate that most of the highly glycosylated B domain of factor VIII is not required for the expression of factor VIII coagulant activity and its interaction with vWF.

Identification and possible function of pro-opiomelanocortin-derived peptides in the testis

Using antibodies against peptides derived from different portions of the POMC molecule, immunocytochemical evidence suggests that this precursor and/or the peptides present within it are localized in testicular Leydig cells of at least five species. There is no evidence for the localization of these peptides or their precursor in any other cell type in this organ. Examination of testicular extracts by gel filtration, SDS-PAGE, and RP-HPLC indicate that the testis contains low concentrations of POMC-derived peptides relative to brain. Further analysis indicates that POMC is processed to alpha-MSH and beta-endorphin similar to its processing in intermediate pituitary lobe and brain. The relative mobilities of immunoreactive alpha-MSH and beta-endorphin on RP-HPLC columns indicate that they are in the unacetylated state as in brain and in contrast to the acetylated forms in the intermediate pituitary lobe. The potential for Leydig cells to synthesize POMC and its peptides was suggested by the demonstration of POMC-like mRNA in total testis and Leydig cell cultures. The size of the POMC-like mRNA is approximately 150 base pairs shorter than anterior or intermediate pituitary POMC mRNA. POMC-like mRNA activity has also been localized to Leydig cells in sections of testes using in situ hybridization. Immunostainable beta-endorphin and other POMC-derived peptides are present in testicular Leydig cells during fetal life and following puberty at times when testosterone secretion is maximal. The accumulation of immunostainable POMC-derived peptides in Leydig cells is dramatically increased by LH and hCG. A variety of observations suggests that testicular cells can respond to POMC-derived peptides. ACTH and the MSHs stimulate growth and cAMP accumulation in Sertoli cells. By contrast, studies using antagonists suggested that beta-endorphin and/or another testicular opioid inhibit Sertoli cell proliferation and ABP secretion. These observations are consistent with the postulate that different portions of the POMC molecule may have opposite effects on Sertoli cell function and suggest a mechanism by which Leydig cells could modulate Sertoli cell activity. Intratesticular administration of opiate antagonists inhibits testosterone secretion both in vivo and in vitro. These observations suggest that Leydig cell-derived beta-endorphin may facilitate testosterone secretion either directly or indirectly. The finding of POMC and its derivative peptides in testis, ovary, adrenal, and placenta suggests that all steroid hormone-secreting organs in mammals may utilize this peptidergic system.

Status of geriatric medicine in the United States

Geriatrics has experienced a gradual and cyclical evolution in the United States. A considerable amount of attention has recently been focused on the status of geriatric medicine and the issue of specialty recognition. Numerous organizations within established medicine have developed position documents and are in the process of re-examining their status. In the United Kingdom, physicians can now be designated as having a special interest in geriatric medicine, and Canada is proceeding with the development of a certificate of special competence in geriatric medicine under the auspices of the Division of Medicine, Royal College of Physicians and Surgeons. This paper presents hypotheses to account for the lack of organization status in geriatrics, and arguments are examined regarding the need for specialty recognition. There is general consensus that geriatrics has an identifiable body of knowledge and skills and that there is need for a cadre of academic geriatricians and educators in geriatrics for students and residents. However, specialty recognition introduces conflict within established specialties that consider care of the elderly crucial to their existence. The options for special recognition, including a certificate of special competence, are described with their advantages and disadvantages. Substantial arguments favor some form of specialty recognition.

Method for the removal of selected cells from cytological smear preparations for transmission electron microscopy

The method described depends on fixing additional cytology smear preparations with glutaraldehyde to be used, if needed. Removal of cells from the slide makes use of partially polymerised resins in the usual way but a paper marker is used to localise the area in the resin block which contains the cells to be examined. Slides are placed in a freezing cabinet to facilitate easy separation of the resin block.

Demonstration of papilloma virus particles in cervical and vaginal scrape material: a report of 10 cases

The finding of virus particles by transmission electron microscopy (TEM) in fixed cervical and vaginal scrape material and their identification as papilloma viruses by negative staining is described. The colposcopic, cytological, and histological appearances in a group of 10 patients in whom virus particles were seen are discussed and the possibly considered of an association between papilloma virus infection and the development of cervical intraepithelial neoplasia (CIN) and multifocal intraepithelial neoplasia of the female lower genital tract.

Mouth lesions in iron-deficient anemia: relationship to Candida albicans in saliva and to impairment of lymphocyte transformation

The atrophic glossitis and angular chilosis in patients with iron-deficient anemia are associated with infection of the mouth by Candida albicans. Saliva from these patients contained more Candida and supported the growth of Candida better than did saliva from a control group. The possibility that growth of Candida may be due to impaired lymphocyte function was investigated by measuring transformation of lymphocytes stimulated with phytohemagglutinin. Transformation was depressed in iron-deficient subjects and returned to normal after correction of their iron status. The lymphocyte count in the peripheral blood was also depressed and corrected by additional iron. Impaired lymphocyte function did not explain the mouth lesions and growth of Candida in saliva since lymphocyte transformation was equally depressed in patients with and without mouth lesions. A local factor, such as an effect of lack of iron on the resident vacterial flora of the mouth, may be important.